This invention relates to an infrared detecting element and also an infrared imaging device.
Some infrared detectors use Si crystals and detect infrared rays having wavelengths equal to or longer than several micrometers. Such infrared detectors are of two types, the first type being produced by doping impurities into the Si crystals and the second type using heterojunction barriers.
Infrared Detectors II, Chapter 2, Semiconductors and Semimetals, written by P. R. Bratt, published from Academic Press in 1977, discloses the first-type infrared detectors.
Japanese published unexamined patent application 61-241985 discloses the second-type infrared detector. The documents "3P79" of the lecture in the thirty-third spring meeting of Applied Physical Society of Japan in 1986 also discloses the second-type infrared detector.
These two types of infrared detectors are useful for infrared two-dimensional imaging devices of a monolithic type. The first-type infrared detectors have the following drawback. Since the quantity of doped impurities is limited, the detector sensitivity is low and the detected wavelength is fixed in dependence on the type of the impurities. Accordingly, it is impossible to maximize the detector sensitivity at an arbitrary wavelength. The second-type infrared detectors are free from such a drawback.


1. Field of the Invention
The present invention relates generally to modern control systems and, more particularly, to negative feedback loops in such systems.
2. Description of the Art
FIG. 1 illustrates a known control system utilizing a negative feedback loop in a low drop-out (LDO) amplifier application 100. This particular application 100 is configured as an LDO regulator circuit. An LDO regulator is a circuit that provides a well-specified and stable DC voltage. The lowest value of differential (input/output) voltage at which the control loop stops regulating is called the dropout voltage. Modern applications such as communication electronics and other battery-powered portable devices require a low dropout voltage and low quiescent currents for increased power efficiency. LDO regulators meet both of these design needs.
At the input stage, a reference input signal VREF is fed into the inverting input of a dual stage amplifier 104. The output from the amplifier controls a field effect transistor (FET) Q1 that acts as a switch for supplying current from the power source VDD to the load (modeled as a resistor RL in the figure). Some of the current flowing between the source and the drain of Q1 is then fed back through a simple RC filter network into the non-inverting input of the amplifier 104. This feedback signal is called VFB. The RC filter network comprises capacitor C1 and resistors R1 and R2. C1 AC-couples the output back into amplifier 104. Resistors R1 and R2 are configured in a voltage divider with R2 connected to ground. The ratio between the values of R1 and R2 may be adjusted to set the output voltage, VOUT, to a desired value.
VOUT is fed back through the RC filtering network yielding signal VFB at the non-inverting input of the amplifier. Typically, differential amplifiers are used in modern electronic circuits. Differential amplifiers amplify the voltage difference between two input signals. When the output of a differential amplifier is connected to its inverting input and a reference voltage signal is applied to the non-inverting input, the output voltage of the op-amp closely follows that reference voltage. As the amplifier output increases, that output voltage is fed back to the inverting input, thereby acting to decrease the voltage differential between the inputs. When the input differential is reduced, the amplifier output and the system gain are also reduced. In FIG. 1, because amplifier 104 is a dual-stage amplifier, the reference signal is shown connected to the inverting input rather than the non-inverting input. Nevertheless, because the output is fed back in a manner that reduces the system gain, the result is negative feedback, sometimes called degenerative feedback.
Negative feedback is often employed to stabilize a control system when the system exhibits a gain from the input to the output. The output stage 120 in this LDO application is modeled by load resistor RL and an output capacitor C0 which is needed to deliver an instantaneous current to a dynamic load. C0 has a characteristic equivalent series resistance (ESR) modeled by a series resistor RESR. ESR is an effective resistance that is used to describe the resistive part of the impedance of certain electrical components such as capacitors.
An important characteristic of this type of control circuit is the ratio between the output and input signal amplitudes, known as the transfer function. The transfer function for any given system is used to model the gain of the system as a function of the input signal frequency. Such control systems are often designed to meet the specifications of a transfer function. The frequency response of the control system is completely described by its transfer function. As such, the stability of a system over a range of input signal frequencies may be predicted based upon properties of its transfer function known as poles and zeros. A pole is a root of the polynomial denominator of a transfer function; a zero is a root of the polynomial numerator.
In designing stable systems, one important consideration is the shift in phase that a signal undergoes as it passes through the system. Poles and zeros are associated with these shifts in phase. If the signal accumulates a shift in phase of 180 degrees, the shift causes the negative feedback to become positive feedback. This is problematic when the system is operating at greater than unity gain as positive feedback will drive the system to an unstable oscillatory state. In order to maintain the stability of the control system, designers often build in a phase shift buffer, called a phase margin. For example, a 50 degree phase margin ensures that the signal never undergoes a phase shift of more than about 130 degrees (i.e. it never comes within approximately 50 degrees of a 180 degree phase shift). 50 degrees is a typical value of a phase margin in an LDO design; however, a 50 degree phase margin is not a requirement for stability and smaller phase margins of 45 degrees or lower may suffice. Furthermore, although a design goal may be to maintain a particular phase margin, the actual performance of a system may be less than the nominal phase margin value. The nominal value of the phase margin is chosen to meet the specifications of a particular design and may vary significantly.
Both poles and zeros can be introduced into the transfer function describing the control loop by inserting various electronic components into the loop. For example, a dual-stage amplifier will create two poles in the transfer function. The addition of poles and zeros into the frequency response of a system must be taken into account in order to design a system with a bounded (finite) output. Unwanted or unavoidable poles and zeros can create significant challenges when trying to stabilize a control system over a range of operating frequencies.
Previously, efforts have been made to stabilize a control system by designing the system so that troublesome poles only affect the system negligibly over the operating frequency range. This approach limits the designer to specific component values and configurations. For example, an output stage may include a capacitor having an ESR which adds a zero to the transfer function at a certain frequency. In order to realize a stable system, the capacitor must be limited to values such that the added zero does not interfere with the system response over the input frequency range. For this reason, small variations in the value of the ESR in an output capacitor can have a significant destabilizing effect on the entire system. A major goal of electronic system design is to avoid limiting circuit components to a precise value or range of values, allowing for easy replacement and substitution of components.
Another previous effort to stabilize control systems involves raising the quiescent current. The quiescent current, sometimes called the leakage current, is the portion of the input current that does not contribute to the load current. In other words, it is the current that the system consumes when no load current is being supplied. By raising the quiescent current, non-dominant poles in the system can be pushed to much higher frequency levels outside the system's normal operating range. A drawback of this stabilization method is that a higher quiescent current drains the batteries that power the system. For this reason many modern applications demand a low quiescent current for increased battery lifetime.


The present invention relates to memory cell layout of CMOS-type SRAM (Complementary Metal Oxide Semiconductor Static Random Access Memory) among semiconductor memory devices.
The SRAM memory cell that comprises six transistors and is made by a typical semiconductor CMOS process is widely used for system LSIs and so on.
The prior art layout pattern of the CMOS-type SRAM memory cell will be described below with reference to FIG. 8.
The prior art SRAM memory cell comprises nMOS drive transistors TN1 and TN2, nMOS access transistors TN3 and TN4, pMOS load transistors TP1 and TP2, polysilicon wires PL1, PL2, PL3 and PL4, wiring layers AL1 and AL2, and contacts CN1, CN2, CL1 and CL2.
The nMOS drive transistor TN1 and the nMOS access transistor TN3 are formed on an n-type diffusion region DN1 and the nMOS drive transistor TN2 and the nMOS access transistor TN4 are formed on an n-type diffusion region DN2. The pMOS load transistor TP1 is formed on a p-type diffusion region DP1 and the pMOS load transistor TP2 is formed on a p-type diffusion region DP2.
Gates of the nMOS drive transistor TN1 and the pMOS load transistor TP1 are connected to each other with the polysilicon wire PL1 and drains of them are connected to each other with the wiring layer AL1 via contact, thereby forming a first inverter (CMOS structure). Gates of the nMOS drive transistor TN2 and the pMOS load transistor TP2 are connected to each other with the polysilicon wire PL2 and drains of them are connected to each other with the wiring layer AL2 via contact, thereby forming a second inverter (CMOS structure). The wiring layer AL1 as an output node of the first inverter is connected to PL2 as an input node of the second inverter, and the wiring layer AL2 as an output node of the second inverter is connected to PL1 as an input node of the first inverter. Thereby a latch circuit for holding data is formed.
A drain of the nMOS access transistor TN3 is connected to the wiring layer AL1 as the output node of the first inverter and source thereof is connected to a bit line (not shown) extending longitudinally via the contact CN1. A drain of the nMOS access transistor TN4 is connected to the wiring layer AL2 as the output node of the second inverter and source thereof is connected to another bit line (not shown) extending longitudinally via the contact CN2. Gates of TN3 and TN4 are connected to a word line (not shown) extending transversally via the contacts CL1 and CL2, respectively.
With such memory cell layout, long lateral distance allows a wide interval between two bit lines so that coupling capacitance between bit lines, which may cause a problem in micro process, can be reduced. Therefore, such memory cell layout is advantageous to speeding-up.
Next, relationship between capability ratio of drive transistors and access transistors and stability of data holding in the SRAM memory cell will be explained with reference to FIGS. 9, 10 and 11.
FIG. 9 shows a memory cell circuit diagram for evaluating stability of data holding. This circuit assumes the situation that the access transistors TN3 and TN4 turns on when the word line is in VDD level for a reading operation, and the bit line is raised to precharge level.
FIG. 10 shows input/output characteristics of two inverter circuits (INV1, INV2) in the latch circuit.
Ain-Aout and Bin-Bout represent characteristics of INV1 and INV2, respectively and it is plotted so as to be Ain=Bout and Bin=Aout. Cross points P1 and P2 in this drawing are stable points and each point corresponds to memory data 0 or 1. In the plot, as area surrounded by two curved lines becomes larger, stability of data holding at P1 and P2 improves. Here, when driving capability of the access transistors TN3 and TN4 becomes greater than that of nMOS transistors (drive transistors) TN1 and TN2 in the inverter circuits, input/output characteristics of the inverter circuits change as shown in FIG. 11. The reason is that the access transistors transmit VDD level of the bit line to the latch nodes more easily, so that area surrounded by two curved lines becomes smaller. When noise voltage is applied into the memory cell having such characteristics, cross points are reduced to be only P2xe2x80x2 and therefore the memory cell can hold only either data. That is, in the case where data other than P2xe2x80x2 (i.e. P1xe2x80x2) is held, the data is destroyed. Thus, maintaining a constant ratio of access transistors to drive transistors in driving capability is important for holding memory cell data stably. Generally, driving capability of access transistors is set to be 50 to 70% of that of drive transistors.
In the prior art SRAM memory cell, channel width of drive transistors is set to be larger than that of access transistors, thereby generating a difference between them in driving capability.
In the prior art SRAM memory cell in which channel width of the drive transistors is set to be larger than that of the access transistors, thereby generating a difference between them in driving capability, the diffusion regions necessarily include some bent parts and end parts. For example, in FIG. 8, the bent parts that produce round-offs as shown by dashed lines DL3 and DL4 are generated by difference between the nMOS drive transistors TN1 and TN2 and the corresponding nMOS access transistors TN3 and TN4 in channel width.
With such layout, at the bent parts of the diffusion regions, finish pattern is rounded off as shown by dashed lines DL1, DL2, DL3 and DL4 in the figure. As a result, a problem arises that transistor width of the nMOS transistors TN1, TN2, TN3 and TN4 becomes larger than required. Moreover, at the end parts of the diffusion regions, finish pattern is retreated as shown by dashed-lines DL5 and DL6. As a result, there arises a problem of reduction in overlap margin of the p-type diffusion region with respect to the contact as well as variation in channel width of the pMOS transistors TP1 and TP2.
Furthermore, system mounted on a semiconductor chip has increasingly become large scale. In connection with this, there is a tendency that the block of SRAM with a large scale in bit capacity is mounted on the chip. In order to meet these requests on the system side, it is desired to further reduce the size of SRAM memory cell. Although it is effective to use a MOS transistor with smaller channel width for the purpose of reducing cell size, such small-sized pattern is prone to undergo great variations in characteristics due to processing fluctuations. Therefore, reduction in cell size makes stable design by sufficient operational margin difficult. On the other hand, with recent micro process, it is more difficult to obtain desirable processed form and round-off or retreat of pattern tend to take place. Moreover, there often causes the phenomenon that even the same pattern form changes in finished form due to peripheral pattern form.
To suppress such changes of processed form, it has already been implemented to correct mask pattern in consideration of bend up and bend down of layout pattern concerned and in consideration of the peripheral layout pattern in recent micro process. Such process, however, is sensitive to apparatus used in semiconductor diffusion process and processing conditions. Further, correction value must be modified each time processing conditions in diffusion process are changed, adding a burdensome operation.
The present invention is made to solve the above-mentioned problems. With the memory cell layout of the semiconductor memory device according to the present invention, it is possible to lay out diffusion regions in linear shapes without any bent part by generating a difference between access transistors and drive transistors in driving capability without changing their channel width. As a result, processed form of diffusion areas of the SRAM memory cell is hard to change, thereby suppressing variations in characteristics of transistors so that transistors with narrow channel width can be used. An object of the present invention is to provide a highly integrated semiconductor memory device by use of such transistors with narrow channel width
A semiconductor memory device according to one aspect of the present invention has a SRAM memory cell comprising: a first inverter including a first nMOS transistor and a first pMOS transistor; a second inverter including a second nMOS transistor and a second pMOS transistor; a third nMOS transistor; and a fourth nMOS transistor, wherein an input node of the first inverter is connected to an output node of the second inverter; and an input node of the second inverter is connected to an output node of the first inverter; either of drain and source of the third nMOS transistor is connected to the output node of the first inverter; the other of drain and source thereof is connected to a first bit line; and gate thereof is connected to a word line; either of drain and source of the fourth nMOS transistor is connected to the output node of the second inverter; the other of drain and source thereof is connected to a second bit line; and gate thereof is connected to the word line; a first diffusion region forming the first nMOS transistor and the third nMOS transistor and a second diffusion region forming the second nMOS transistor and the fourth nMOS transistor, respectively, are arranged in linear shapes without having any bent part, and current driving capability of the first and second nMOS transistors is higher than that of the third and fourth nMOS transistors.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that gate length of the third and fourth nMOS transistors is longer than that of the first and second nMOS transistors.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that threshold voltage characteristics of the third and fourth nMOS transistors are higher than those of the first and second nMOS transistors.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that a gate oxide film of the third and fourth nMOS transistors are thicker than that of the first and second nMOS transistors.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that driving voltage of the word line is lower than power supply voltage supplied to the first and second inverters.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that a third diffusion region forming the first pMOS transistor and a fourth diffusion region forming the second pMOS transistor are arranged in linear shapes without having any bent part and located in parallel to the first and second diffusion regions.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device further comprising: a third pMOS transistor formed adjacent to drain of the first pMOS transistor on the third diffusion region; and a fourth pMOS transistor formed adjacent to drain of the second pMOS transistor on the fourth diffusion region, wherein gates of the first nMOS transistor, the first pMOS transistor and the fourth pMOS transistor are connected in succession via a first polysillicon wire; and gates of the second nMOS transistor, the second pMOS transistor and the third pMOS transistor are connected in succession via a second polysillicon wire; and absolute value of threshold voltage of the third and fourth pMOS transistors is higher than power supply voltage supplied to the first and second inverters.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that n-type diffusion regions are provided on the opposite side of the diffusion region of the third pMOS transistor to the first pMOS transistor and on the opposite side of the diffusion region of the fourth pMOS transistor to the second pMOS transistor to fix potential of N-well region forming pMOS transistors.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that, in a memory cell array in which the SRAM memory cells are arranged in a grid pattern, a substrate contact region for fixing well potential is provided at regular intervals in the extending direction of the first and second diffusion regions; a diffusion region forming the substrate contact region is arranged in a linear shape without any bent part on the extension of the first diffusion region and the second diffusion region of the memory cell; and a fifth nMOS transistor is provided at the boundary of the memory cell and the substrate contact region wherein gate potential thereof is fixed so as not to become ON state.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that, in a memory cell array in which the SRAM memory cells are arranged in a grid pattern, a substrate contact region for fixing well potential is provided at regular intervals in the extending direction of the third and fourth diffusion regions;, a diffusion region forming the substrate contact region is arranged in a linear shape without any bent part on the extension of the third diffusion region and the fourth diffusion region of the memory cell; and a fifth pMOS transistor is provided at the boundary of the memory cell and the substrate contact region wherein gate potential thereof is fixed so as not to become ON state.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that the first pMOS transistor is formed on the third diffusion region; the second pMOS transistor is formed on the fourth diffusion region; and the first, second, third and fourth diffusion regions are arranged at equally spaced intervals in the longitudinal direction of connect line of transistor gate.
A semiconductor memory device according to another aspect of the present invention is an above-mentioned semiconductor memory device characterized in that the first pMOS transistor is formed on the third diffusion region; the second pMOS transistor is formed on the fourth diffusion region; and the first, second, third and fourth diffusion regions are arranged so as to have same width measured in the longitudinal direction of connect line of transistor gate.
As a means of generating a difference in transistors"" capability without changing channel width, channel length of the access transistors is set to be longer than that of the drive transistors. This enables memory cell data to be held stably. In the prior art difference in capability has been generated from difference in channel width. Therefore, even if minimum width of diffusion region, which is possible in processing, can be applied to the access transistors, the drive transistors cannot be laid out at minimum width. According to the present invention, however, minimum width of diffusion region can also be applied to the drive transistors. In typical transistors, channel width is longer than channel length, and therefore reduction in channel width in the present invention probably can reduce cell size.
However, in the prior art memory cell layout as shown in FIG. 8, because of its long sideways structure, longer channel length, which increases cell height, weakens the effect of reducing area by reduction in channel width of the drive transistor. Accordingly, in the present invention, as another means of generating a difference in transistors"" capability, threshold voltage of the access transistor is set to be greater than that of the drive transistor. Further, as other means, gate oxide film of the access transistor is set to be thicker than that of the drive transistor. By use of these means, the access transistor and the drive transistor have different capability while having the same channel length and width so that the effect of reducing area can be obtained. In the case that the above-mentioned means for changing characteristics of the access transistor are employed, it is necessary to add a supplementary process, suffering a slight increase in process costs. Therefore, as another means according to the present invention, power supply voltage supplied to a word line driving circuit for driving the gate of the access transistor is set to be lower than that supplied to a latch circuit in the memory cell. As a result, it is possible to generate a capability difference between the access transistor and the drive transistor having the same size and characteristics, thereby holding process costs down.
As for the p-type diffusion region, removing end parts that exist in the prior art layout is employed. The p-type diffusion regions are arranged in linear shapes, and for the separation of pMOS load transistor devices between vertically adjoining cells, a pMOS separating transistor having an absolute value of threshold voltage greater than power supply voltage and being in OFF state at any time irrespective of gate potential is formed. This suppress changes of processed form in channel width of the load transistor due to retreat of pattern that occurs at the end part in the prior art, and also allows a sufficient overlap of the diffusion region with respect to the contact in the drain of load transistor. Looking from the aspect of the n-type diffusion region, the p-type diffusion region always lies next to the n-type diffusion region as its peripheral layout form. In the prior art layout, as the p-type diffusion region does not exist partly next to the n-type diffusion region, the processed form of the n-type diffusion region changes a part and the change must be corrected on the mask data. According to the present invention, the processed form of the n-type diffusion region can be improved without any correction.
Furthermore, fixing potential of N well forming the pMOS transistors by applying n-type diffusion on the opposite side of a pMOS separating transistor to load transistor is employed. Therefore, vacant region in the memory cell can be used effectively as substrate contact region. The substrate contact region for fixing potential of P well may be separately formed outside of the memory cell. Nevertheless, as potential of N well can be definitely fixed, latch-up resistance is improved. Moreover, a potential-fixed region of P well that formed separately can be set at larger intervals, thereby enabling area of the memory cell array to be suppressed.
Considering the layout of the whole memory cell array, it is necessary to provide the potential-fixed region of P well at regular intervals in the vertical direction of aligning memory cells. With the prior art layout, diffusion regions of memory cells above and under the potential-fixed region are necessarily separated. According to the present invention, by providing transistors whose gates are fixed in OFF state above and under the potential-fixed region both in n-type diffusion region and p-type diffusion region, the above-mentioned potential-fixed region of N well can be arranged in a linear shape in contiguous to the diffusion region of the memory cell. In this way, over the whole memory cell array, diffusion regions can be laid out in linear shapes without any bent part and partial separation, so that change in characteristics of transistors above and under the potential-fixed region can be suppressed.
Furthermore, in the present invention, placing each diffusion region at the same interval is employed. As mentioned above, in recent micro process, finished processed form changes due to peripheral layout form. In the case of plural placement intervals, it becomes difficult to shape plural diffusion regions into desired interval and width. Maintaining a constant placement interval facilitates keeping forms of these diffusion regions constant. Similarly, placing each diffusion region at the same width is employed. It also facilitates keeping width and forms of these diffusion regions constant.
The novel features of the invention are set forth with particularity in the appended claims. The invention as to both structure and content, and other objects and features thereof will best be understood from the detailed description when considered in connection with the accompanying drawings.


Folding frames having four or more pivot points may be relatively easy to design. Folding frames having three pivot points exactly may be rather difficult to design but may result in functional structures that have the added benefit of being aesthetically pleasing to many eyes.


Surfboards may generally be described as water planing devices used to ride waves. The term “surfboard” may include boogie boards, wind surfing boards, and other hulled craft which are maneuvered by shitting the weight borne by the craft relative to the craft's center of gravity. Surfboards may be constructed of various lengths, width, shapes and thicknesses. Initially, surfboards had a single vertical fin located along the centerline of the surfboard at the rear that provided directional stability. Later designs added additional smaller fins of various sizes and shapes along the sides of the surfboard to improve the stability and maneuverability of the surfboards.
In terms of its design, a surfboard fin is analogous to a “fixed wing.” The surface curvature of conventional fins reflects architecture similar to that of a “fixed wing” aircraft. When the physics are applied to an aqueous environment, the “fixed wing” is termed a “hydrofoil” or sometimes simply a “foil.”
Holding all other variables constant and for a constant hydrofoil speed, the velocity of water passing over the top surface of the hydrofoil wing is greater than that which passes below the flat bottom surface. With an increase in water velocity over the top of the hydrofoil wing, the pressure of the water over this surface is reduced when compared to the pressure below the hydrofoil wing. This difference in pressure tends to push the hydrofoil wing toward the side of lowest pressure of the pressure gradient. The velocity of the water over the top surface of the wing is forced to rise with increased velocity because (a) water is essentially incompressible and (b) the distance a water molecule must travel for a given linear distance is longer due to the curvature of the wing over the hydrofoil surface as compared to the straight line distance enjoyed by water molecules passing below the hydrofoil wing. The upward force generated through relative motion between the wing and the environment through which it travels, in this case water, is proportional to the velocity of the water over the wing surfaces and the surface area of the wing's bottom surface. The velocity of a surfboard is largely a function of wave height, wave velocity, and gravity.
A reduction in lift may be expected from “turbulence” or “cavitation” that could theoretically develop over the wing surface. For example, turbulence may be created by high surface friction coefficients and disrupt desired laminar flow. Cavitation is a phenomenon whereby gasses actually come out of solution in the surrounding water mass due to significant pressure reduction. Similar to opening a carbonated beverage, and under the appropriate temperature and pressure conditions, air bubbles may form in the low pressure zones over the wing's surface. Cavitation may disrupt laminar flow and will also produce aquatic sounds as the bubbles collapse and return to solution.
The single vertical fin is generally speaking, a type of hydrofoil, whose function is to provide lift or some other force to the surfboard in reaction to its motion through the water. The single vertical fin is usually a symmetrical foil (a “50/50” foil) with both sides convex, which provides for even water flow on both sides of the fin such that a single vertical fin promotes stability and control. If the hydrofoil has a convex, top surface and a flat bottom surface, the velocity of water flow over the top surface of the hydrofoil is increased, thus creating a water pressure differential between the bottom and top surfaces and producing Sift or thrust in the direction of the pressure differential toward the area of lowest pressure.
The performance of a surfboard is affected by the design, placement, and number of fins affixed to the surfboard. For example, a fin may be defined by its dimensions: its base, its depth, its sweep, its flex, and its cant, and changes in these dimensions affect the performance characteristics of the surfboard. As for the hydrofoil effects, the fin may be the aforementioned symmetrical foil or a flat foil having one flat side and one convex side, which promotes maneuverability and fast transitions between turns. Other fins may combine the characteristics of a symmetrical foil and a flat foil in various proportions dependent on the desired performance characteristics of the surfboard. For optimum foil performance, flexibility in design characteristics is necessary, as well as the ability to modify these design characteristics as surfing conditions change.
Therefore, as competitive surfers attempt more challenging maneuvers and ride bigger waves, there is need for improved fin designs that improve the lift, maneuverability, and other performance characteristics of the surfboards.


There are over nine million dairy cows in the United States and Canada, and over twenty million worldwide. The dairy industry is a very competitive marketplace, and the pregnancy status of the herd is critical to maximizing profits. It is estimated that a non-pregnant cow costs the industry approximately five dollars per day. An accurate, rapid test for determining the pregnancy status of a herd would have a very important economic impact on ranch or farm operations and would increase milk production of the dairies, resulting in increased profitability for the dairies.
A number of antigens are known to be present in cows and sheep during pregnancy, and pregnancy has been evaluated by a variety of methods. Bovine Antigen Glycoprotein (U.S. Pat. No. 4,755,460, issued Jul. 5, 1988, and U.S. Pat. No. 4,895,804, issued Jan. 23, 1990) can be measured about 12-15 days after breeding. Early Pregnancy Factor (EPF) (U.S. Pat. No. 4,877,742, issued Oct. 31, 1989, and WO 00/51520, published Sep. 8, 2000) levels can be measured at about 20-40 days after breeding, such as with KEMS BioTest Ltd. (Littleton, Colo.) Animal Rapid Test for Bovine Pregnancy.
Interferon-tau is produced by bovine trophoblast tissue between days 15-24 of bovine gestation and prevents luteolysis by suppressing endometrial PGF2α secretion. Interferon-tau induces or upregulates expression of a number of proteins in pregnant animals.
Proteins that are induced by IFN-T include granulocyte chemotactic protein (GCP-2) (WO 94/12537, published Jun. 9 1994 and Staggs, K. L. et al. [1998] “Complex Induction of Bovine Uterine Proteins by Interferon Tau” Biol. Reprod. 59:293-297), 2′,5′-oligoadenylate synthetase (Short, E. C. et al. [2001] “Expression of antiviral activity and induction of 2′,5′-oligoadenylate synthetase by conceptus secretory proteins enriched in bovine trophoblast protein-1” Biol. Repro. 44:261-268), β2-microglobulin (Vallet, J. L. et al. [1991] “A low molecular weight endometrial secretory protein which is increased by ovine trophoblast protein-1 is a β2-microglobulin-like protein,” J. Endocrinology 130:R1-R4), IFN regulatory factors 1 (IRF-1) and 2 (IRF-2) (Spencer, et al. [1998] Biol. Reprod. 58:1154-1162; and Binelli M. et al. [2001] Biol. Reprod. 64(2):654-665), GCP-2 (Teixeira, M. G. et al. [1997] Endocrine 6:31-37); and 1-8U, 1-8D, and Leu-13/9-27 (Pru, J. K. et al. [2001] “Pregnancy and Interferon -T Upregulate Gene Expression of Members of the I-8 Family in the Bovine Uterus” Biol. Reprod. 65:1471-1480; and Pru, J. K. [2000] “Regulation of bovine uterine proteins and prostaglandin F2a release by interferon-tau” Ph.D. Thesis, University of Wyoming). Leu-13 is the name of the protein encoded by the 9-27 gene. Cyclooxygenase-2 (COX-2) (Xiao, CW et al. [1998] “Regulation of COX-2 and prostaglandin F2a synthase gene expression by steroid hormones and IFN-T in bovine endometrial cells,” Endocrinol. 139:2293-2299 and Thatcher, W. W. et al. [2001] A Uterine-conceptus Interactions and Reproductive Failure in Cattle” Theriogenology 56:1435-1450) and PLA2 (Binelli, M. et al. [2000] “Interferon-tau modulates phorbol ester-induced production of prostaglandin and expression of cyclooxygenase-2 and phospholipase-A2 from bovine endometrial cells” Biol. Repro. 63:417-424) are also regulated by IFN-T.
Teixeira, M. G. et al. (1997) “Bovine Granulocyte Chemotactic Protein-2 is Secreted by the Endometrium in Response to Interferon-tau,” Endocrine 6(1):31-37 report that bovine 1-8 transcripts were detected on Days 15 and 18 of pregnancy and were absent on Day 12 of pregnancy and during the estrus cycle. Bovine 1-8 gene family members are not known to be secreted. This reference also reported that polyclonal antibodies to a GCP-2 peptide, were generated in sheep, and used to demonstrate that GCP-2 is secreted by cultured endometrial cells, representing Day 14 of the estrus cycle, when dosed with IFN-T.
Mx encodes a monomeric GTPase and is induced by IFN-T (Ott, T. L. et al. [1988] “Effects of the Estrous Cycle and Early Pregnancy on Uterine Expression of Mx Protein in Sheep (Ovis aries)” Biol. Reprod. 59:784-794). In Ott et al. (1998), ovine Mx protein was detected using a monoclonal antibody directed against the amino terminus of human MxA (1319.35.126, supplied by M. Horisberger, Novartis, Basel Switzerland) and a Super ABC Mouse/Rat Kit (Biomeda, Foster City Calif.). U.S. patent application Ser. Nos. 60/299,553 and 10/166,929 describe a method of determining pregnancy status of an animal by assaying the level of Mx and comparing it to the level of Mx in a non-pregnant animal. Mx protein was detected with ovine Mx peptide antiserum (#90618-2). Yankey, S. J. et al. (2001) “Expression of the antiviral protein Mx in peripheral blood mononuclear cells of pregnant and bred, non-pregnant ewes” J. of Endocrinology 170:R7-R11, describes the presence of Mx in peripheral blood mononuclear cells of pregnant ewes at Day 15 of pregnancy. Mx protein can also be used to detect viral infection (EP 0 725 081, published Aug. 7, 1996) using monoclonal antibodies to human Mx. Antibodies to human Mx and immunoassays for Mx have been described (Staeheli, P. and Haller, O. [1985] “Interferon-induced human protein with homology to protein Mx of Influenza virus-resistant mice” Mol. Cell. Biol. 5(8):2150-2153; Towbin H. et al. [1992] “A Whole Blood Immunoassay for the Interferon-Inducible Human Mx Protein” J. Interferon Res. 12(2):67-74; U.S. Pat. Nos. 5,869,264, issued Feb. 9, 1999; U.S. Pat. No. 5,739,290, issued Apr. 14, 1998; and U.S. Pat. No. 6,180,102 issued Jan. 30, 2001). Antibodies to mouse Mx are described in Staeheli, P. et al. (1985) Mol. Cell Biol. 5:2150-2153; Staeheli, P. et al. (1985) J. Biol. Chem. 260(3):1821-1825; and Horisberger, M. A. et al. (1985) J. Biol. Chem. 260(3):1730-1733. One of the monoclonal antibodies in Towbin (1992) is reported to react with other species' Mx proteins (mouse, rat, bovine, and porcine), in addition to human Mx.
Another IFN-T-induced protein is ubiquitin cross-reactive protein (UCRP), which was first identified in humans (Farrell, P. J. et al. [1979] Nature 279:523-525) and later characterized (Koran, B. D. [1984] “Interferon-induced Proteins” J. Biol. Chem. 259(23):14835-14839; Blomstrom, D. C. et al. [1986] J. Biol. Chem. 261:8811-8816; and Knight E. Jr. et al. [1988] J. Biol. Chem. 263:4520-4522). Human UCRP (hUCRP) and mouse UCRP encode proteins that are processed to 17 kDa but that migrate as 15 kDa on PAGE gels (Potter, J. L. et al. [1999] “Precursor processing of pro-ISG15/UCRP, an interferon-beta-induced ubiquitin-like protein” J Biol. Chem. 274:25061-25068). These proteins are similar to ubiquitin, and are upregulated by interferon (IFN), hence they are also known as interferon-stimulated gene 15 (ISG15). ISG15 is involved in the viral response and in the recognition of pregnancy (Bebington, C. et al. [1999] “Localization of Ubiquitin and Ubiquitin Cross-Reactive Protein in Human and Baboon Endometrium and Decidua During the Menstrual Cycle and Early Pregnancy” Biol. Reprod. 60:920-928, and Bebington, C. et al. [1999] “Ubiquitin Cross-Reactive Protein Gene Expression is Increased in Decidualized Endometrial Stromal Cells at the Initiation of Pregnancy” Molecular Human Reproduction 5(10):966-972). Like ubiquitin, ISG15 becomes covalently attached to targeted intracellular proteins via a C-terminal LRGG amino acid sequence. Proteins that are coupled to ubiquitin often are degraded through the 26 S proteasome (Baboshina, O. V. [1996] “Novel multiubiquitin chain linkages catalyzed by the conjugating enzymes ESEPF and RAD6 are recognized by 26 S proteasome subunit 5,” J Biol. Chem. 271:2823-2831). Ubiquitin is conjugated to other proteins by E2-conjugating enzymes (Tanaka, K. et al. [1998] “The ligation systems for ubiquitin and ubiquitin-like proteins” Mol. Cell 8:503-512).
The 17 kDa bovine analog of hUCRP (ISG15) was identified as bovine UCRP (bUCRP) or ISG17 (Austin, K. J. et al. [1996] “Ubiquitin Cross-Reactive Protein is Released by the Bovine Uterus in Response to Interferon During Early Pregnancy,” Biol. Reprod. 54:600-606; Austin, K. J et al. [1996] “Complementary Deoxyribonucleic Acid Sequence Encoding bovine Ubiquitin Cross-Reactive Protein,” Endocrine 5(2):191-197; and Perry, D. J. et al. [1999] “Cloning of Interferon-Stimulated Gene 17: The Promoter and Nuclear Proteins That Regulate Transcription,” Molecular Endocrinology 13:1197-1206). ISG17 becomes covalently linked to targeted intracellular proteins, is released from endometrial cells, and may function as a paracrine modulator. Unlike ISG15, ISG17-conjugated proteins continue to accumulate rather than be degraded. Two of the 1-8 gene family members, bovine 1-8U and bovine Leu-13, have high homology with the E2-conjugating enzymes, and they retain critical amino acids for function. It has been suggested that they may function by conjugating ISG17 to proteins.
A normal bovine estrus cycle is about 21 days in length. ISG17 has been detected by Day 15 of pregnancy. It continues to increase to Day 17, and remains high through Day 26 (Hansen, T. R. et al. [1997] “Transient Ubiquitin Cross-Reactive Protein Gene Expression in the Bovine Endometrium,” Endocrinology 138(11):5079-5082; and Spencer, T. E. et al. [1999] “Differential Effects of Intrauterine and Subcutaneous Administration of Recombinant Ovine Interferon Tau on the Endometrium of Cyclic Ewes,” Biol. Reprod. 61:464-470). ISG17 was not detectable above background during the estrus cycle of non-pregnant bovine.
One ISG17 function is to become cross-linked to cellular proteins, as does ubiquitin. Conjugation of ISG17 to endometrial cytosolic proteins was observed by Western Blotting using a polyclonal antibody to an ISG17 polypeptide (Johnson, G. A. et al. [1998] “Pregnancy and Interferon-Tau Induce Conjugation of Bovine Ubiquitin Cross-Reactive Protein to Cytosolic Uterine Proteins,” Biol. Reprod. 58:898-904). The peptide used to generate the polyclonal antibodies corresponds to amino acids 82 to 99 of ISG17. This polypeptide was chosen because it had a high antigenic index, 78% identity with ISG15, and low identity (22%) with ubiquitin. Attempts to use the antiserum to develop a pregnancy test met with limited or no success (Pru, J. K. [2000] “Regulation of bovine uterine proteins and prostaglandin F2a release by interferon-tau” Ph.D. Thesis, University of Wyoming, Appendix 1, page 1). Another antibody which has been utilized in the study of ISG17 is monoclonal antibody 5E9 (Pru, J. K. [2000] “Regulation of bovine uterine proteins and prostaglandin F2a release by interferon-tau” Ph.D. Thesis, University of Wyoming, Appendix 1).
The Johnson polyclonal antibody to ISG17 amino acids 82-89 was also used to study ISG17 induction by IFN-T by Western blotting (Staggs, K. L. et al. [1998] “Complex Induction of Bovine Uterine Proteins by Interferon Tau,” Biol. Reprod. 59:293-297).
ISG17 also can induce expression of IFN-T in peripheral blood mononuclear cells (PMBCs) (Pru, J. K. et al. [2000] “Production, Purification, and Carboxy-Terminal Sequencing of Bioactive Recombinant Bovine Interferon-Stimulated Gene Product 17,” Biol. Reprod. 63:619-628).
Ovine UCRP (oUCRP) has been cloned (Charleston, B. and Stewart, H. J. [1993] “An interferon-induced Mx protein: cDNA sequence and high level expression in the endometrium of pregnant sheep,” Gene 137:327-331). Ovine UCRP is reported to be detectable by Day 13, and to remain high through Day 19 of ovine pregnancy (Johnson, G. A. et al. [1999] “Expression of the Interferon Tau Inducible Cross-Reactive Protein in the Ovine Uterus,” Biol. Reprod. 61:312-318). Western blotting of oUCRP was performed using a polyclonal antibody to human UCRP.
Other factors, in addition to IFN-T, may be responsible for the induction of UCRP (Johnson, G. A. et al. [2000] “Interferon-tau and Progesterone Regulate Ubiquitin Cross-Reactive Protein Expression in the Ovine Uterus,” Biol. Reprod. 62:622-627.
Estrone sulfate was found to be increased around day 50 in bovine peripheral blood. (Hirako, M. and Takahashi, H. [2000], “Oestrone sulfate commences an increase around 50 days of gestation in bovine peripheral blood,” Reprod. Fertil. Dev. 12(7-8):351-354. Estrone sulfate analysis in urine or serum after Day 100 has also been used to confirm pregnancy (Holdsworth et al. [1982] J. Endocrin. 95:7-12 and Warnick et al. [1995] Theriogenol. 44:811-825).
PSP60 is disclosed in Mialon, M. M., et al. (1993), “Peripheral concentration of a 60-kDa pregnancy serum protein during gestation and after calving and in relationship to embryonic mortality in cattle,” Reprod. Nutr. Dev. 33(3):269-82, to be present in peripheral blood from day 27 after artificial insemination until and beyond the end of pregnancy. Mialon, M. M., et al. (1994), “Detection of pregnancy by radioimmunoassay of a pregnancy serum protein (PSP60) in cattle,” Reprod. Nutr. Dev. 34(1):65-72 discloses that testing 349 cows for PSP60 28, 35, 50 and 90 days post-insemination gave accurate results compared with other known tests. Patel, O. V., et al. (1998), “Effect of stage of gestation and fetal number on plasma concentration of a pregnancy serum protein (PSP-60) in cattle,” Res. Vet. Sci. 65(3):195-199 discloses that PSP60 increased from day 20 post-oestrus to 20 days pre-partum.
Pregnancy-associated glycoprotein 1 (PAG-1) is disclosed in Xie, S., et al. (1991), “Identification of the major pregnancy-specific antigens of cattle and sheep as inactive members of the aspartic proteinase family,” Proc. Nat'l Acad. Sci. USA 88(22):10247-10251. This article teaches that pregnancy in cattle and sheep can be diagnosed by the presence of this conceptus-derived antigen in maternal serum. Zoli, A. P., et al. (1992), “Radioimmunoassay of a bovine pregnancy-associated glycoprotein in serum: its application for pregnancy diagnosis,” Biol. Reprod. 46(1):83-92 discloses a double-antibody radioimmunoassay for bovine PAG-1 which was detected in maternal peripheral blood beginning at day 22 of pregnancy and increasing progressively to day 270, and becoming undetectable by day 100 postpartum. Xie, S. et al. (1997), “The diversity and evolutionary relationship of the pregnancy-associated glycoproteins, an aspartic proteinase subfamily consisting of many trophoblast-expressed genes,” Proc. Nat'l Acad. Sci. USA 94(24):12809-12816, teaches that cattle, sheep and probably all ruminant artiodactyla possess up to 100 or more pregnancy-associated glycoprotein genes, many of which are placentally expressed. Szenci, O. et al. (1998), “Evaluation of false ultrasonographic diagnoses in cows by measuring plasma levels of bovine pregnancy-associated glycoprotein 1,” Vet. Rec. 142(12):304-306 taught that this antigen showed that before day 31 ultrasonographic scanning was not very sensitive because six of the 30 calving cows were incorrectly diagnosed as non-pregnant. 0.5 ng/ml was used as the cut-off point to determine pregnancy. Pregnancy Associated Glycoproteins (PAGs) can also be detected during early pregnancy (WO 99/47934, published Sep. 23, 1999). Szenci, O. et al. (1998) “Comparison of Ultrasonography, Bovine Pregnancy-Specific Protein B, and Bovine Pregnancy-Associated Glycoprotein 1 Tests for Pregnancy Detection in Dairy Cows” Theriogenology 50:77-88, describes a comparison of bovine pregnancy tests for days 26 to 58 after artificial insemination (AI). Green, J. et al. (2000), “Pregnancy-associated bovine and ovine glycoproteins exhibit spatially and temporally distinct expression patterns during pregnancy,” Biol. Reprod. 62(6):1624-1631, discloses that pregnancy-associated glycoproteins in sheep and cows are expressed in the trophectoderm or binucleate cells. Those expressed predominantly in bovine binucleate cells are expressed weakly if at all by day 25 placenta, but are present at the middle and end of pregnancy. Others, such as PAG-4, -5 and -9 are present at Day 25 and at earlier stages. Roberts, R. M., et al. (1995), “Glycoproteins of the aspartyl proteinase gene family secreted by the developing placenta,” Adv. Exp. Med. Biol. 362:231-240, teaches that pregnancy in cattle and sheep can be diagnosed by the presence of placentally-derived antigens (pregnancy-associated glycoproteins or PAG-1) in maternal serum soon after implantation begins at about day 20 following conception.
Pregnancy-specific Protein B (PSPB) is disclosed in U.S. Pat. Nos. 4,554,256, issued Nov. 19, 1985; 4,705,748, issued Nov. 10, 1987; European Patent No. 0132750, published Feb. 13, 1985; and Sasser, R., et al. (1986), “Detection of pregnancy by radioimmunoassay of a novel pregnancy-specific protein in serum of cows and a profile of serum concentrations during gestation,” Biol. Reprod. 35(4):936-942. Serum concentrations of PSPB exceeded 1 ng/ml by 30 days post-breeding and increased gradually through three months, six months, and nine months of gestation, declining steadily to less than 78 ng/ml by 21 days postpartum. PSPB could be measured in most cows by 24 days after breeding. Szenci, O. et al. (1998), “Comparison of ultrasonography, bovine pregnancy-specific protein B, and bovine pregnancy-associated glycoprotein 1 tests for pregnancy detection in dairy cows,” Theriogenology 50(1):77-88, teaches that at days 26 to 58 after artificial insemination, pregnancy testing with PSPB-diagnosed pregnant cows as accurately as measuring of PAG-1 or ultrasound; however, there were fewer false positive diagnoses with the PSPB test than the PAG-1 test. PSPB has also been tested in llamas (Drew, M. I. et al. [1995] “Pregnancy determination by use of pregnancy-specific protein B radioimmunoassay in llamas” JAVMA 207(2):217-219); deer (Willard, S. T. et al. [1998] “Early pregnancy detection and the hormonal characterization of embryonic-fetal mortality in fallow deer” Theriogenology 49:861-869; and sheep (Willard, J. M. et al. [1995] “Detection of fetal twins in sheep using a radioimmunoassay for PSPB” J. Anim. Sci. 73:960-966) for detection of twins. PSPB is also detectable after calving (Kiracofe, G. H. et al. [1993] “PSPB in serum of postpartum beef cows” J. Anim. Sci. 71:2199-2205). Polyclonal antibodies against PSPB are described in U.S. Pat. No. 4,705,748 and Humblot et al. (1988), “Pregnancy-specific protein B, progesterone concentrations and embryonic mortality during early pregnancy in dairy cows,” Reprod. Fertil. 83(1):215-223.
Progesterone is an antigen which is present throughout pregnancy. Progesterone levels have been measured in milk or blood samples collected from cattle after 22-24 days, such as offered at Rocky Mountain Instrumental Laboratories Inc. (Fort Collins, Colo.), but measurements of progesterone in milk at days 18-22 yield unacceptably high rates of false positives (Oltenacu et al. [1990] J. Dairy Sci. 73:2826-2831 and Markusfeld et al. [1990] Br. Vet. J. 146:504-508). Moriyoshi, M. et al. (1996), “Early pregnancy diagnosis in the sow by saliva progesterone measurement using a bovine milk progesterone qualitative test EIA kit,” J. Vet. Med. Sci. 58(8):737-741 discloses that pregnancy could be diagnosed 17-24 days after last mating in sows. Polyclonal antibodies to progesterone are commercially available from many different sources including Research Diagnostics, Inc., Flanders, N.J., and are described in Humblot, F., et al. (1988) “Pregnancy-specific protein B., progesterone concentrations and embryonic mortality during early pregnancy in dairy cows,” Reprod. Fertil. 83(1):215-223. Monoclonal antibodies to progesterone are available commercially through OEM Concepts, Tom's River, N.J.
Johnson, G. A. et al. (1998) “Pregnancy and Interferon-Tau Induce Conjugation of Bovine Ubiquitin Cross-Reactive Protein to Cytosolic Uterine Proteins,” Biol. Reprod. 58:898-904, discloses polyclonal antibodies to ISG17. The peptide used to generate the polyclonal antibodies corresponds to amino acids 82 to 99 of ISG17, LVRNDKGRSSPYEVQLKQ. This polypeptide was chosen because it had a high antigenic index, 78% identity with ISG15, and low identity (22%) with ubiquitin. Attempts to use the antiserum to develop a pregnancy test met with limited or no success (Pru, J. K. [2000] “Regulation of bovine uterine proteins and prostaglandin F2a release by interferon-tau” Ph.D. Thesis, University of Wyoming, Appendix 1, page 1). Another antibody which has been utilized in the study of ISG17 is monoclonal antibody 5E9 (Pru, J. K. (2000) “Regulation of bovine uterine proteins and prostaglandin F2a release by interferon-tau” Ph.D. Thesis, University of Wyoming, Appendix 1). U.S. patent application Ser. No. 60/393,615 discloses cDNAs believed to be associated with early bovine pregnancy.
Prior bovine pregnancy tests have tested only single antigens. However, false positives may occur when single antigens are tested, since positive test results may occur for these antigens when certain viruses are present. Some antigens such as progesterone are present in lactating cows. Thus a test is needed which will reliably determine bovine pregnancy with minimal false positive results.
Methods of making assay devices are described in Millipore's Short Guide for Developing Immunochromatographic Test Strips (2nd ed). Other assay devices and methods are described in U.S. Pat. Nos. 4,313,734, 4,376,110, 4,435,504, 4,486,530, 4,703,017, 4,740,468, 4,855,240, 4,954,452, 5,028,535, 5,075,078, 5,137,808, 5,229,073, 5591645, 5,654,162, 5,798,273, and in EP 0810436A1, and WO 95/16207. Assay devices containing more than one test strip are described at the Unitec, Inc. website.
In cows, the estrus cycle is about 21 days. To determine when a cycling cow is ready for breeding, the cow can be observed for behavioral estrus. Alternatively, a cow can be induced or forced into estrus with effective hormone therapies. Estrus of an entire herd can be synchronized (U.S. Pat. Nos. 3,892,855 issued Jul. 1, 1975, and 4,610,687 issued Sep. 9, 1986). Estrus synchronization, or preferably ovulation synchronization, is used in timed AI (TAI) breeding programs. TAI breeding programs involve precise estrus synchronization which allows for timed breeding without monitoring for behavioral estrus. Examples of methods for forcing estrus include U.S. Pat. No. 5,589,457 (issued Dec. 31, 1996), Ovsynch (Pharmacia Animal Health, Peapack, N.J.), Cosynch, Select Synch, Modified Select Synch, MGA/PGF, and Syncro-Mate-B. Such methods typically employ hormones such as prostaglandins, e.g. PGF2α (Lutalyse7, Pharmacia Upjohn, Peapack, N.J.; Bovilene7, Syntex; Animal Health, Des Moines, Iowa; and Estrumate7 Haver Lockhart, Shawnee, Kans.), and gonadotropin-releasing hormone (GnRH). Ovsynch involves a GnRH injection followed by a prostaglandin injection one week later, followed by a second GnRH injection 48 hours later. Insemination is ideally then performed at 12-18 hours, preferably about 16 hours, after the second GnRH injection. Ovsynch is maximally effective when implemented between Days 18-20 of a 20-day bovine estrus cycle (Thatcher, W. W. et al. [2000] “New Strategies to Increase Pregnancy Rates” at the website nab-css.org/education/Thatcher.html. Presynch (Pharmacia Animal Health, Peapack, N.J.) can be used to synchronize heifers before implementing Ovsynch. Presynch involves two prostaglandin injections. Some of the above-mentioned methods are also used on non-cycling cows to induce cycling, such as in lactating dairy cows. After precise estrus synchronization, animals need not be monitored for behavioral estrus and may be bred by appointment. Some animals may need estrus presynchronization before estrus synchronization. Melengestrol acetate (MGATM) in feed (Imwalle, D. B. et al. (1998) “Effects of melengestrol acetate on onset of puberty, follicular growth, and patterns of luteinizing hormone secretion in beef heifers” Biol. Repro. 58:1432-1436) or implants (U.S. Patent Publication No. 2001/0041697, published Nov. 15, 2001) can be used for presynchronizing estrus in heifers. Resynch is a program whereby animals are synchronized and bred, and then those animals that are determined to be open (not pregnant) are again synchronized and rebred.
Prostaglandin alone has been administered sequentially or simultaneously with artificial insemination to reduce the number of insemination administrations per herd required for achieving pregnancy (WO 02/04006, published Jan. 17, 2002).
Prostaglandin can be used as a single injection. An injection of about 2-5cc of Lutalyse (prostaglandin PGF2α) will induce an animal with a mature corpus luteum to come into estrus in about 48-96 hours. Cattle typically have a functional corpus luteum during Days 5-18 of the cycle (Estrus Synchronization of Cattle, Publication F-3163, Oklahoma Cooperative Extension Service, Oklahoma State University). Animals induced into estrus can be bred at 2-5 days following a prostaglandin injection. Single injection prostaglandin programs are often used with estrus synchronization, corpus luteum palpation, or behavioral heat detection because only animals in certain stages of the estrus cycle will respond by going into estrus. Breeding by appointment with a standard prostaglandin program has not been recommended because the interval from injection to estrus varies depending on the stage of the cycle when prostaglandin is administered. For example, if a cow is at cycle Day 7-8 or Day 15-17, timed AI can be performed at about 72-80 hours after the injection (O'Connor, M. L. discussion found at the website inform.umd.edu/EdRes/topic/AgrEnv/ndd/reproduce and das.psu.edu/reproduction/check/pdf/synchron.pdf. A risk of using prostaglandin injection for forcing estrus is that prostaglandin can cause abortion when given to pregnant animals. Estrus and ovulation synchronization allows cattle managers to concentrate heat detection efforts in a relatively short period of time or allows for TAI, which requires no heat detection (see the website ianr.unl.edu/beef/g741.htm).
There is a need in the art to determine pregnancy status during the breeding of livestock. In cattle, conception rates are low (Streenan and Diskin, Eds. [1986] Embryonic Mortality in Farm Animals, Martinus Nijhoff Publishers, 1-11) and spontaneous abortion rates are high, making pregnancy/non-pregnancy determination and rebreeding/inseminating important management tools. Particularly there is a need to determine pregnancy/non-pregnancy status during the estrus cycle in which insemination occurs or the first estrus cycle after insemination so that animals that are not pregnant can be most economically rebred. This need is particularly strong when raising livestock such as cattle, especially on dairy farms.
There is a need in the art for tests that determine pregnancy, and particularly non-pregnancy, status of animals during the estrus cycle in which insemination occurs or during the first estrus cycle after insemination. Knowing which animals are non-pregnant allows efforts to be directed towards forcing non-pregnant animals into estrus and/or watching for signs of estrus, in preparation for insemination, to decrease the time an animal is not pregnant. Pregnancy is dependent, not only on conception/fertilization but also on maternal recognition of pregnancy during the critical period, which allows for implantation. Up to 40% of total embryonic losses are estimated to occur between Days 8 and 17 of pregnancy in cattle (Thatcher, W. W. et al. [1994] “Embryo Health and Mortality in Sheep and Cattle,” J. Anim. Sci. 72(Suppl. 3):16-30). In the absence of reliable pregnancy tests, the earliest time at which a non-pregnant animal can be identified is at the beginning of a new estrus cycle, by observation of behavioral estrus. Optimally, pregnancy/nonpregnancy status is determined towards the end of or after the critical period when pregnancy is maintained, Days 15-17 according to Binelli, M. et al. (2001) “Antiluteolytic Strategies to Improve Fertility in Cattle,” Theriogenology 56:1451-1463, but before the end of the first estrus cycle, Days 18-20, allowing timed artificial insemination programs to be maximally effective. This reference discloses that pregnancy/non-pregnancy status is optimally determined during Days 17-18.
Additional technology relating to pregnancy testing in cows and other animals is disclosed in U.S. Provisional Patent Application Nos. 60/377,987, 60/377,166, 60/380,043, 60/377,921, 60/377,165, 60/377,355, 60/377,829, and 60/380,042, all filed May 2, 2002.
All references cited herein are incorporated herein by reference in their entirety to the extent that they are not inconsistent with the disclosure herein. Citation of the above documents is not intended as an admission that any of the foregoing is pertinent prior art. All statements as to the date or representation as to the contents of these documents is based on subjective characterization of the information available to the applicant, and does not constitute any admission as to the accuracy of the dates or contents of these documents.


The invention relates to portable screen systems.
Previously, it has been known to provide portable screen systems for separating fine material from coarse material wherein the frame of the unit is lowered flush onto preferably flat level ground, and material to be processed which overflows beyond side ends of the screen builds up along end sides of the unit. A set of wheels are made movable relative to the frame from an operative position for transporting the apparatus to an inoperative position for resting the frame flush on the ground. Such a unit is shown, for example, in U.S. Pat. Nos. 4,197,194, Des. 263,836, 4,237,000, and 4,256,572.
There are significant disadvantages with such a system. If the ground onto which the frame is rested in flush fashion is not level and/or bumpy and undulating, the vibrating screen will not be level side-to-side, and the material placed on the vibrating screen will be inefficiently processed and tend to shift more to one side of the screen than the other and thus be unevenly distributed. Accordingly, with the aforementioned unit, the ground on which the frame is positioned in flush manner should be level and not bumpy or undulating.
A further disadvantage is that during operation of the aforementioned unit, overflow material to the sides of the unit builds up around the wheels and the side walls and can interfere with removal of the unit from the site due to such build-up of overflow material. Also, build-up of material where the frame sits flush on the ground may impede removal during freezing weather if such material were to freeze and trap the frame.
Another disadvantage of the above described unit is that if the frame resting on the ground settles unevenly during operation, the unit may become tilted, particularly if a rock was in contact with one small portion of the frame.


1. Field of the Invention
The present invention relates to a printed circuit board (PCB) antenna and, more particularly, to a PCB antenna capable of receiving four operating bands.
2. Description of Related Art
Recently, wireless communication products have gradually become a part of regular living. For example, mobile communication devices such as cell phones, have advanced to the “Third Generation” (3G) while ‘bluetooth’ products, providing great flexibility of PC devices etc, are becoming commonplace. The design of modem wireless communication products places great emphasis compactness, versatility, portability and aesthetics. However, when integrating a wireless communication product with a contemporary antenna, the size and appearance of the antenna seriously detract from the aesthetics of the communication product. Furthermore, the antenna can receive only a single band signal, which is not satisfactory. Currently, commercial wireless applications are approaching maturity, especially in reference to the computer information industry such that change from a wired network to a wireless network is well under way. However, in response to 2.4 GHz˜2.5 GHz/5.15 GHz˜5.25 GHz/5.25 GHz˜5.35 GHz/5.725 GHz˜5.85 GHz frequency bands being opened by the global wireless local network market, it has become necessary to integrate a number of different band antennas into a single wireless communication product. This integration will occupy too much space in the communication products and reduce convenience and reliability in use.
Therefore, it is desirable to provide an improved antenna to mitigate and/or obviate the aforementioned problems.


1. Field of the Invention
The present invention is generally directed to an improved apparatus and method for intermittent manufacturing nitrogen gas, separated from air by using a permeable membrane in an automatic and unattended process. Particularly, the improved method and device adds a gas flow measuring device in a gas conduit downstream from the permeable membrane. The gas flow measuring device indirectly monitors nitrogen gas purity by measuring normal gas flow and detects deviation from desired nitrogen purity levels by measuring changing gas flow from the permeable membrane. The nitrogen and vent gas flow rates from the permeable membrane relate to the nitrogen purity so monitoring either or both the nitrogen and/or vent gas flow indirectly monitors the nitrogen gas purity. The automated process allows non-skilled people to use nitrogen gas from an automatic nitrogen producing apparatus. These people need assurances that the nitrogen gas meets purity requirements.
2. Description of the Prior Art
Nitrogen manufacture from air by separating the oxygen and nitrogen has been accomplished by selective absorbent materials, distillation of liquid air, and membrane separation. These processes produce nitrogen for industrial uses such as chemical manufacture, inert gas welding, purging of explosive environments prior to electric arc cutting or welding, and food preservation. Also, these processes are mostly continuous nitrogen production to the industrial process or to continually fill large storage containers. The prior art is referenced in U.S. Pat. No. 5,588,984.
This U.S. Pat. No. 5,588,984, describes a method and apparatus to intermittently manufacture and dispense nitrogen. Air is filtered, compressed, and enters a module containing a permeable membrane that selectively separates nitrogen from the air and discharges vent oxygen and other gases. Automated temperature and pressure monitors allow the permeable membrane to separate air components. A discharge hose permits use of the nitrogen product for a variety of intermittent applications including vending for inflation of tires, filling portable nitrogen vessels, and use in manufacturing processes.
During the use of this apparatus, debris, moisture, or oil collecting in the membrane may affect the permeable membrane efficiency of separating nitrogen from air. The membrane may need cleaning or other possible malfunctions from the air compressor, temperature, or pressure controls would change the apparatus efficiency or nitrogen purity. In large production and continuous manufacturing of nitrogen for storage or commercial use, a direct purity analysis method uses oxygen analyzers to indicate and monitor nitrogen purity. These oxygen analyzers directly determine the percent of oxygen, using electrochemical fuel cells thereby relating nitrogen purity to oxygen purity. One oxygen analyzer, manufactured by Teledyne, uses an expensive replaceable cell, needs monthly calibration, and is warranted for only six months while having a one year life. The analyzer is not rugged and would present a reliability problem for intermittent nitrogen production. An information sheet concerning these analyzers is enclosed. Oxygen gas analyzers usually require monitoring by manufacturing personnel to maintain the purity of nitrogen in constant flow nitrogen manufacture.
For automatic, intermittent operation by users of nitrogen, unfamiliar with the apparatus, a method and device for signaling an alarm and/or automatic shutdown of the nitrogen manufacturing apparatus is needed if the nitrogen purity is unacceptable. To replace the direct oxygen purity analysis equipment, an indirect monitor device using simple, reliable, and long life flow indicators, pressure monitors, and/or flow switches are used in intermittent apparatus operation down stream of the permeable membrane to monitor the purity of nitrogen gas. These gas flow devices do not require maintenance/and last appreciably longer than one year.


The present invention relates to a data handling system having a redundant storage configuration. More particularly, the present invention relates to a data storage suitable for averaging workload and for matching contents between storage devices having duplicate data, respectively, and constituting a redundant storage arrangement.
Japanese Published Patent Application No. 06-259336 discloses a technique for matching contents between a master extended storage device and a sub extended storage device both of which constitute a redundant storage configuration. The disclosed technique involves matching the order in which to perform store operations on the master and the sub extended storage devices in order to keep contents identical between the master and the sub extended storage devices. However, the disclosure contains no reference to fetch operations on the master and the sub extended storage devices.


1. Field of the Invention
The inventive arrangements relate generally to the field of projection television receivers and displays and more particularly to projection television receivers and displays that employ imagers such as liquid crystal on silicon imagers.
2. Description of Related Art
There have been many new developments in various types of electronic displays and video imaging devices. One example of such technology is liquid crystal on silicon (LCOS). As is known in the art, an LCOS imager generally contains an array of row and column electrodes such that the pixels of the LCOS imager can be addressed by selection of these row and column electrodes.
Typically, a video input signal is selectively fed to each of the column electrodes, and selection of a row electrode enables each cell corresponding with the pixels to be charged to a desired pixel voltage. This permits video to be written to each of the rows of pixels. The video input signal is transferred to the column electrodes from a bus and through a number of switches connected to the bus and the column electrodes. These switches remain closed only for brief periods of time. A particular cell remains lighted with the same intensity until the video input signal changes that cell thereby acting as a sample and hold. That is, the pixel does not decay, as is the case with the phosphors in a cathode ray tube. Notably, many imagers permit the row electrodes to be selected in a sequential fashion, and some permit the row electrodes to be selected in a non-sequential manner.
Current LCOS imagers, however, suffer from a significant drawback known as column memory. As the video input signal is transferred to a column electrode and the switch through which the input signal is passing opens, a charge remains on the column electrode. Thus, when the next row electrode is activated, the charge that is left over from the previous charging of the column electrode remains on the column electrode until the switch is closed again to write video to the new row of pixels. This residual charge can result in scene content from the previously written row being displayed in the new row being written thereby causing a phenomenon known as “ghosting.” The ghosting effect can be particularly troublesome if rows are selected in a non-sequential manner, as the voltage levels on the column electrodes from the previous row selection may be significantly different from the current row selection. Thus, it is desirable to eliminate the ghosting effect without significantly increasing system costs or complexity.


In an automatic transaction machine such as an automated teller machine, generally configuration is made, as shown in FIG. 5A and FIG. 5B, such that a rear door 102 is unlocked and opened, and an opening-and-closing cover 101 provided for example to an operation panel is opened by removing screws from the rear so as to enable maintenance such as of internal units.
A cover opening-and-closing support mechanism is provided at an automatic transaction machine such as an automated teller machine in order to facilitate opening of the heavy opening-and-closing cover 101 when performing maintenance. A gas spring 91 shown in FIG. 5B assists raising of the opening-and-closing cover 101. A gas spring stopper 92, described later, also locks the gas spring 91 such that the opening-and-closing cover 101 cannot be closed.
In order to close the opening-and-closing cover 101 after maintenance has been completed the cover opening-and-closing support mechanism is configured so as to close slowly when the gas spring stopper 92 is pressed and released.
A cover opening-and-closing support mechanism of such a related automatic transaction device 100 is configured, as shown in FIG. 4, with a gas spring 91 and a gas spring stopper 92.
The gas spring 91 is configured with a cylinder section 91c and a rod section 91d. A gas spring pivot point 91a is provided to the gas spring 91 at the top end of the cylinder section 91c, this being on the side of the opening-and-closing cover 101. A gas spring pivot point 91b is provided at the bottom end of the rod section 91d, this being on the side which is fixed to the cabinet of the automatic transaction device 100.
The gas spring stopper 92 is configured from a stopper portion 92a, a limiter portion 92b, and a spring 93. The stopper portion 92a locks the gas spring 91. The limiter portion 92b is provided so that the stopper portion 92a does not contact the rod section 91d of the gas spring 91 and damage the rod section 91d. The spring 93 is a biasing member for biasing the gas spring stopper 92 towards the gas spring 91 as indicated by arrow A, so as to cause the stopper portion 92a to contact the gas spring 91 as shown in the intermittent lined Region a.
Such a gas spring is attached to the opening-and-closing cover in order for example to push against the weight of the opening-and-closing cover during opening and closing. However, the reaction force from the gas pressure decreases as the gas spring 91 ages. The gas spring stopper 92 is therefore provided to prevent the opening-and-closing cover 101 from sagging. A stopper profile is provided at the gas spring stopper 92 that utilizes the difference between the external profiles of the cylinder section 91c and the rod section 91d of the gas spring 91.
Examples of biasing members include a tension coil spring, as shown in FIG. 4, a compression coil spring that similarly presses the gas spring stopper 92 in the arrow A direction, and torsion springs that are for example attached to the gas spring pivot point 91a and bias in the arrow A direction (see for example Japanese Patent Application Laid-Open (JP-A) No. 10-115340).


A structure of a 3GPP LTE (3rd Generation Partnership Project Long Term Evolution; hereinafter, referred as “LTE”) system which is an example of a wireless communication system to which the present invention may be applied will be described.
FIG. 1 illustrates a schematic structure a network structure of an evolved universal mobile telecommunication system (E-UMTS). An E-UMTS system is an evolved version of the UMTS system and basic standardization thereof is in progress under the 3rd Generation Partnership Project (3GPP). The E-UMTS is also referred to as a Long Term Evolution (LTE) system. For details of the technical specifications of the UMTS and E-UMTS, refer to Release 7 and Release 8 of “3rd Generation Partnership Project; Technical Specification Group Radio Access Network”.
Referring to FIG. 1, the E-UMTS includes a User Equipment (UE), base stations (or eNBs or eNode Bs), and an Access Gateway (AG) which is located at an end of a network (E-UTRAN) and which is connected to an external network. Generally, an eNB can simultaneously transmit multiple data streams for a broadcast service, a multicast service and/or a unicast service.
One or more cells may exist for one BS. The cell provides a downlink or uplink transmission service to several UEs using any one of bandwidths of 1.25, 2.5, 5, 10, 15 and 20 MHz. Different cells may be set to provide different bandwidths. A BS controls data transmission or reception to or from a plurality of UEs. The BS transmits downlink scheduling information to a UE with respect to downlink (DL) data so as to inform the UE of time/frequency domain, coding, data size, Hybrid Automatic Repeat and reQuest (HARQ) associated information of data to be transmitted, or the like. The BS transmits uplink scheduling information to a UE with respect to uplink (UL) data so as to inform the UE of time/frequency domain, coding, data size, HARQ associated information used by the UE, or the like. An interface for transmitting user traffic or control traffic can be used between BSs. A Core Network (CN) may include the AG, a network node for user registration of the UE, or the like. The AG manages mobility of a UE on a Tracking Area (TA) basis. One TA includes a plurality of cells.
Wireless communication technology has been developed to reach the LTE based on Wideband Code Division Multiple Access (WCDMA), but demands and expectations of users and providers have continuously increased. In addition, since other aspects of wireless access technology continue to evolve, new advances are required to remain competitive in the future. There is a need for reduction in cost per bit, service availability increase, the use of a flexible frequency band, a simple structure and an open type interface, appropriate power consumption of a UE, etc.


1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, a printer and a multifunction machine, and, moreover, to a sheet stacking device stacking a sheet (recording medium) formed with an image, and a sheet processing device performing post processing of a sheet.
2. Description of the Related Art
A sheet processing device with the following configuration has been well known as a sheet processing device into which a sheet with an image formed in an image forming apparatus is conveyed. The sheet processing device has a buffer roller through which, when the sheet processing device receives sheets, which have been formed with an image, and have been discharged from an image forming apparatus main body, the received sheets are superimposed for temporary waiting before the sheets are conveyed to a post processing mechanism such as a stapling machine and a saddle stitching machine. That is, while a preceding sheet bundle is processed in a processing tray, first several sheets of the succeeding sheet bundle are on the buffer roller for temporary waiting. When the preceding sheet bundle, which has been processed, is discharged from the processing tray, the succeeding several sheets, which have been delivered from the buffer roller, are conveyed to the processing tray. A brief explanation of a sheet post-processing device with the above-described configuration will be given, referring to FIG. 9A through FIG. 9C.
A plurality of sheets P1, P2, . . . are superimposed one on top of another and wrapped around a buffer roller 5 to form a wrapping path 32. For example, three sheets P1, P2, and P3 are superimposed one on top of another, delivered from the path 32 after temporary waiting, conveyed, and conveyed to a processing tray 101 through a discharge roller 7, bundle discharge rollers 180a, and 180b. When the rear ends of the sheets pass the discharge roller 7, the bundle discharge rollers 180a and 180b rotate in the reverse direction in such a way that the sheet bundle of three sheets P1, P2, and P3 is returned in the direction in which the sheets abut against a rear-end stopper 3 of the processing tray 101. Alignment is performed in such a way that the bundle discharge roller 180b is separated from the bundle discharge roller 180a just before the rear end of the sheet bundle abuts against the rear-end stopper 3 and the sheet bundle abuts against the rear-end stopper 3 by moving inertia. At this time, alignment in a direction perpendicular to the conveyance direction is performed, using aligning plates.
When all the sheets of the first sheet bundle are aligned on the processing tray 101 in such a manner, a swinging guide 150 is lowered and the bundle discharge roller 180b sits atop the sheet bundle to perform stitching processing of the sheet bundle, and the like, using a processing machine such as a stapling machine indicated by a reference number 4 in FIG. 9A.
According to the above-described procedures, a first plurality of sheets of the succeeding second sheet bundle are wrapped around the buffer roller 5 as a temporary accumulating unit for waiting until processing for the first sheet bundle is completed. Thereby, a high-speed image forming apparatus by which sheets are discharged from the main body of an image forming apparatus at a small interval may be realized. Incidentally, the varieties of the quality and the size of sheets have been further increased in recent years. But the sheet processing device shown in FIG. 9A through FIG. 9C may hardly treat sheets, for example, special paper such as coated paper, the surface of which is treated, thick one, and large-sized one.
Even if these kinds of sheets may be surely aligned one by one, it is difficult to align a plurality of the sheets in a state in which the sheets are superimposed. That is, the rear ends of a plurality of the sheets with a special quality, or with a special sheet size is run into the rear-end stopper 3 on the processing tray 1. In this case, there is generated a state in which all the three sheets P1, P2, and P3 with a large coefficient of friction, such as that of coated paper, are not completely returned to the rear end of the stopper 3. Especially, it is serious that the sheet P2 such as the second sheet of the superimposed ones is incompletely or faultily returned, that is, the quality of the post processing is deteriorated, and, consequently, the productivity is reduced. Moreover, when a plurality of sheets such as a thick one, and a large-sized one are superimposed and moved, there is caused larger inertia than the one caused in a case in which one sheet is moved. Accordingly, there is a case in which non-aligning is caused, because the sheets are vigorously run into the rear-end stopper 3 and bound. Moreover, there is a possibility that the end portion of the sheet buckles, and is damaged.


Many computing systems today utilize multiple processing units, resulting in a computer architecture generally referred to as multiprocessing. Multiprocessing systems are often used for transaction processing, such as airline and banking systems. Transaction processing refers generally to a technique for organizing multi-user, high volume, on-line applications that provides control over user access and updates of databases. A transaction refers to the execution of a retrieval or an update program in a database management system. Transactions originating from different users may be aimed at the same database records. This situation, if not carefully monitored, may cause the database to become "inconsistent". Where all transactions are executed one after the other, the database will remain in a consistent state.
To maintain transaction indivisibility, either all database updates in a transaction processing system or none of the updates are applied to the database. In prior art systems, database management systems have retained a copy of the existing data whenever the transaction requests a database update. If the transaction proceeds to a stable point, all new updates are secured to the database by the database management system. If the transaction does not proceed to a stable point because a failure occurs before the updates are secured to the database, none of the updates are applied. The prior art systems typically use control messaging between various components in the transaction processing system to ensure that each database transaction request is processed once and only once. If this complex synchronization between these various components is not maintained, the data in the database can become inconsistent. However, the synchronization between these components is very complex, and causes undesirable system overhead inefficiencies.
Therefore, it is desirable to provide a system for providing transaction indivisibility without the complex synchronization between various system components. The present invention provides a solution to this problem by providing a centralized system accessible by all components, where an indivisibility analysis can be performed for all source messaging, regardless of which terminal or associated host processor initiated the transaction. The present invention therefore provides a solution to the aforementioned and other problems, and offers other advantages over the prior art.


Conventionally, in the coating of an automobile body, midcoat coating, baking, overcoat base coating, overcoat clear coating and baking are sequentially performed on a coated product on which electrodeposition coating serving as an undercoat and baking are performed. In other words, since a total of three rounds of baking are needed, a reduction in the number of times baking is performed has been required in terms of reducing the amount of CO2 discharged and saving energy.
Hence, a coating method has been proposed in which, in the coating of an automobile body, baking is not performed after midcoat coating, wet-on-wet overcoat coating is performed, and a midcoat coating film and an overcoat coating film are baked and cured simultaneously (see, for example, Patent Document 1). This coating method is a so-called 3-coat 2-bake (hereinafter referred to as “3C2B”) coating method in which a total of three rounds of coating (undercoat, midcoat and overcoat) and a total of two rounds of baking are performed.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2005-177631


Enterprises employ a vast number of protocols for internal and/or external communications and information transfer in order to ensure reliability, security and compliance with particular policies. For example, internal and/or external communications and information transfer can include, but are not limited to instant messaging (IM), electronic mail (email), Internet Protocol (IP) telephony, web mail, web-browsing, text messaging over a network of two or more computers (or network connectable, processor-based devices), and the like. These electronic communication media are popular as they provide inexpensive, easy, point-to-point communication that is less intrusive than traditional techniques and/or disparate non-electronic communications. There is an abundance of other benefits, for example, instant messaging (IM) is an electronic communication that easily enables one-to-many communication, there is no need to synchronize participants and the content can be planned more easily, among other things. Unfortunately, these media have adversaries and/or protocols that threaten the convenience of and confidence in their use, namely spam, viruses, malware, etc.
A variety of systems and techniques have been developed and employed to combat spam and malicious code related to electronic communication media. With an increase in malicious activity involving spam, viruses, malware, and the like, enterprises are continuously searching for efficient techniques to secure networks and respective data communications associated therewith. Thus, conventional techniques (e.g., content-based filters, IP address-based filters, etc.) are becoming ineffective in recognizing and blocking disguised spam messages in relation to electronic communications. The integrity of enterprises and data communications is imperative to success in which improvements are necessary to ensure security and/or protective techniques are less vulnerable, stronger, and more difficult to penetrate.


A person's “cognitive load” is the degree to which the person's working memory is engaged in processing information. The more working memory is used, the higher the cognitive load. The higher a person's cognitive load, the greater the chances that “distracted operating” will impact the person's performance in operating a piece of equipment.
For instance, a person driving an automobile while operating a hand-held electronic device (e.g., text messaging on a cellular device) will experience an elevated cognitive load as the person tries to operate both the automobile (the equipment) and the hand-held electronic device at the same time. This impact on performance can be generally referred to as one type of “distracted driving.”
According to the National Highway Traffic Safety Administration (NHTSA), “distracted driving” is a dangerous epidemic on America's roadways, as evidenced by the fact that in 2009 alone, it is estimated that nearly 5,500 people were killed, and 450,000 people were injured in distracted driving crashes.
“Distracted operating” isn't limited to distractions caused by the utilization of hand-held electronic devices while operating equipment. Many other activities, events and situations can elevate a person's cognitive load. For instance, other activities, events and/or situations which can elevate a person's cognitive load include, but are not limited to, stress, mood, grief, the person's physical and/or mental health, the person's age, the person's maturity, cigarette smoking, eating, drinking, emergencies, sleepiness, weather conditions, the presence of hazards, “multi-tasking” (e.g., operating the equipment while also utilizing social media, playing games, watching television, listening to music, and/or talking on the telephone).
“Impaired operating” (e.g., under the influence of alcohol, under the influence of illegal drugs, under the influence of prescription drugs) is likewise a concern. For instance, the impact of alcohol on a person's performance in operating an automobile is well known.
Therefore, a need exist for methods of, and apparatuses for, determining if a person operating equipment is experiencing an elevated cognitive load.


In vehicles using electric traction motors, alternating current (AC) motor drives are used to provide a requested torque to the motor shaft. In practice, the amount of torque produced by the motor is directly related (although not perfectly proportional) to the amount current provided to the motor. Therefore, by regulating and precisely controlling the input current to the electric motor, the amount of torque produced by the electric motor may be more accurately controlled. In response to a changing torque command, the motor torque response is smoother and/or faster when the amount of current provided to the electric motor is adjusted based on the torque command.
For purposes of efficiency, particularly in hybrid and/or electric vehicles, it is desirable to maximize the ratio of the output torque to the input motor current. However, in many systems, the input motor current is not directly controlled. For example, many electric motors are operated using pulse-width modulation (PWM) techniques in combination with an inverter (or another switched-mode power supply) to control the voltage across the motor windings, which in turn, produces the desired current in the motor. In response to a requested torque (or commanded torque), most prior art systems determine a desired input motor current for producing the requested amount of torque and utilize a closed loop control system to control the current through the motor windings and thereby regulate the amount of torque produced the motor. One or more sensors are used to measure the actual motor current, which is then compared to the desired input motor current. Based on the outcome of the comparison, the PWM commands for the inverter are adjusted to increase and/or decrease the voltage across the motor windings, such that the actual measured motor current tracks the desired input motor current.
However, when a current sensor does not accurately measure the motor current, these closed-loop control systems can no longer effectively control the motor torque. For example, without accurate motor current information, the control system may cause the motor to produce insufficient torque, excessive torque, or varying or oscillating amounts of torque. Furthermore, as a preventative measure in some prior systems, in response to a current sensor error, the control system may cease providing current and/or voltage to the electric motor, or drastically reduce the amount of current and/or voltage provided to the electric motor. As a result, in prior art systems, when a current sensor error occurs, the use and enjoyment of a particular vehicle is adversely affected.


(a) Field of the Invention
The present invention relates to a variable valve apparatus.
(b) Description of the Related Art
A typical combustion chamber of an automotive engine is provided with an intake valve, for supplying an air/fuel mixture, and an exhaust valve, for expelling burned gas. The intake and exhaust valves are opened and closed by a valve lift apparatus connected to a crankshaft.
A conventional valve lift apparatus has a fixed valve lift amount due to a fixed cam shape. Therefore, it is impossible to adjust the amount of gas that is introduced or exhausted. However, valve timing and amount of lift should ideally be optimized for different driving speeds.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.