The present invention relates to a biaxially stretch-oriented multilayer film essentially comprising a propylene homopolymer, comprised of a highly pigmented base layer and a thin modified top layer applied to one or both of its surfaces. The invention also relates to the manufacture and use of the film.
Decorative laminate panels are widely used for producing furniture, e.g., kitchen and office furniture, but also for outdoors applications, e.g., as windowsills, etc. Special types are used under extremely severe conditions, e.g., in shower cubicles or bathrooms or as benches in chemical laboratories. The last mentioned applications, in particular, require panels which are extraordinarily resistant to scratches, to organic and aqueous solvents and to detergents. Apart from imparting a special optical appearance, the surface texture is of particular importance in respect to these characteristic features.
Laminate boards of the type described above have, for example, been disclosed by German Offenlegungsschrift No. 34 18 282. As a rule, the core layer of a laminate panel is comprised of a multilayer structure comprising a plurality of paper webs impregnated with a phenolic resin. A cellulose paper which is impregnated with a melamine resin and which may be unicolored or printed with a multicolored pattern, is usually applied to this core layer as a top layer.
Prior to the actual pressing of the top layer(s) and the core layer, the resin-impregnated papers of the core and top layers are dried and thereby partially condensed. The subsequent actual pressing is in general performed by means of heatable or coolable, automatically controlled multi-level pressing units where up to 40 laminate panels can be produced simultaneously. So-called high pressure laminates (H.P.L.) are compressed at pressures of between 70 and 100 bar and temperatures of between 140.degree. and 160.degree. C. During the compression, the resins flow and are cured, whereby a compact, non-meltable, rigid, crosslinked product is formed. Suitable presses include intermittently and continuously working units and through-feed units.
If a plurality of panels are stacked on top of one another in the presses, which is economically advantageous for low-thickness core layers, the individual panels must be separated by separators. To produce smooth surfaces, polished metal sheets having plane high-gloss surfaces are used as separators. If the laminate panels are to exhibit a textured or matte surface (for example, resembling veining or fabric texture), appropriately textured templates are required.
In order to prevent a sticking-together of the templates and resinous surfaces in those cases where textured templates are used, an additional release sheet must be inserted between the actual separator and the surface of the laminate. Apart from paper and aluminum foil, biaxially stretch-oriented polypropylene foil has been increasingly used for this purpose in recent times.
When clear (transparent) stretch-oriented polypropylene films are employed as release sheets, high-gloss surface finishes are obtained. If, however, matte surface finishes are desired, the manufacturers have to fall back on brushed aluminum foils. More recently, highly pigmented, biaxially stretch-oriented polyester films have also been employed. It is a common disadvantage of these two release films, which are used to produce matte or structured surfaces, that they are relatively expensive.
Attempts have been made to employ a highly pigmented, i.e., opaque, polyolefin film as a release film, instead of the expensive, highly pigmented polyester films. Polyolefin films of this type are, for example, described in German Offenlegungsschrift No. 28 14 311 (equivalent to U.S. Pat. No. 4,303,708). There is, however, the risk that the surfaces of the laminate panels stick to these release films.


The present invention relates to a flame retardant resin material and a flame retardant resin composition, and more particularly to a flame retardant resin material and a flame retardant resin composition which are improved in flame retardancy, thermal stability or thermal decomposition resistance, and moisture resistance.
In order to prevent flame, it is required that resin compositions has a flame retardancy. Usually, halogen flame retardants are used as flame retardants whilst antimony trioxide is used as a co-flame retardant co-used along with the flame retardant. The halogen flame retardants generate harmful halogen substances, typically dioxins. The antimony trioxide as the co-flame retardant has a chronic toxicity. For those reasons, the above substances raise a problem in safety in fire or waste disposal. Phosphoric flame retardants such as red phosphorus and ester phosphate are effective to avoid the above problem. Those phosphoric flame retardants provide influences to moisture resistance of the resin compositions. Particularly, insulators for electronic components are required to have a high reliability. Those phosphoric flame retardants are a problem in use for the insulators for electronic components.
On the other hand, epoxy resin compositions are superior in mechanical properties, adhesive property, chemical resistance property, heat resistance and insulating properties, for which reason the epoxy resin compositions are used in various fields in adhesive, coating materials, laminated plates, molding materials and injection materials. In case of the epoxy resin compositions, halogen flame retardants are used as flame retardants whilst antimony trioxide is used as a co-flame retardant. If the flame retardant and the co-flame retardant are used for the epoxy resin composition, problems in not only safety but also corrosion of metals are raised. If those epoxy resin compositions are used as insulators for the electronic components, corrosion resistance to interconnections under high temperature is lowered, whereby reliability of the electronic device is deteriorated. For this reason, it had been required to develop other epoxy resin compositions free from the halogen flame retardant and antimony trioxide.
It was investigated to improve the flame retardancy of the resin material by introducing a triazine ring into a molecular structure of an epoxy resin or a phenol resin. In Japanese laid-open patent publication No. 8-311142, it is disclosed that mixtures of phenols with compounds having triazine rings and with aldehydes or phenol condensates such as phenol triazine resins are used as a hardening agent for the epoxy resin compositions. In Japanese laid-open patent publication No. 10-279657, it is disclosed that a phenol triazine epoxy resin obtained by glycidyl-etherification of the above described phenol triazine resin is used as a main component of the epoxy resin composition.
There is, however, the following problem in introducing the triazine rings into the molecular structures of the epoxy resins and the phenol resins.
The flame retardancy of the resin compositions including the phenol triazine resins and the phenol triazine epoxy resins is exhibited due to a flame reducing mechanism by flame resistant gases which contain, as a main component, nitrogen compounds generated by decomposition of triazines. If in order to emphasize the flame reducing effect, a content of nitrogen in the resin composition is increased, then the resistance to the thermal decomposition of the resin composition is deteriorated, whereby the flame retardancy is thus deteriorated. Since triazines have hydrophilicity, the increase in content of the triazines (nitrogen) in the resin composition causes a remarkable reduction in moisture resistance.
Consequently, it is difficult to further improve the flame retardancy of the resin composition by introducing nitrogen compounds into the molecular structure of the resin composition.
In the above circumstances, it had been required to develop a novel flame retardant resin material and a novel flame retardant resin composition free from the above problems.
Accordingly, it is an object of the present invention to provide a novel flame retardant resin material free from the above problems.
It is a further object of the present invention to provide a novel flame retardant resin material having a high frame retardancy.
It is a still further object of the present invention to provide a novel flame retardant resin material having a high thermal stability or a high thermal decomposition resistance.
It is yet a further object of the present invention to provide a novel flame retardant resin material having a high moisture resistance.
It is further more of the present invention to provide a novel flame retardant resin composition free from the above problems.
It is moreover object of the present invention to provide a novel flame retardant resin composition having a high frame retardancy.
It is another object of the present invention to provide a novel flame retardant resin composition having a high thermal stability or a high thermal decomposition resistance.
It is still another object of the present invention to provide a novel flame retardant resin composition having a high moisture resistance.
The present invention provides a flame retardant phenol resin material which includes a phenol condensate, wherein a poly-aromatic compound obtained by a reaction of phenols (A) to aromatics (B) except for phenols and a heterocyclic compound (C) including nitrogen as heteroatom are condensed via aldehydes (D).
The present invention also provides a flame retardant epoxy resin material which includes an epoxy resin obtained by glycidyl-etherification of at least a part of phenolic hydroxyl groups of a poly-aromatic compound obtained by a reaction of phenols (A) to aromatics (B) except for phenols and a heterocyclic compound (C) including nitrogen as heteroatom are condensed via aldehydes (D).
The present invention also provides a flame retardant resin composition including a flame retardant phenol resin material which includes a phenol condensate, wherein a poly-aromatic compound obtained by a reaction of phenols (A) to aromatics (B) except for phenols and a heterocyclic compound (C) including nitrogen as heteroatom are condensed via aldehydes (D).
The present invention also provides a flame retardant resin composition including a flame retardant epoxy resin material which includes an epoxy resin obtained by glycidyl-etherification of at least a part of phenolic hydroxyl groups of a poly-aromatic compound obtained by a reaction of phenols (A) to aromatics (B) except for phenols and a heterocyclic compound (C) including nitrogen as heteroatom are condensed via aldehydes (D).
The above and other objects, features and advantages of the present invention will be apparent from the following descriptions.


Field of the Invention
Embodiments of the present invention generally relate to performing capacitance sensing while updating a display, or more specifically, to performing capacitance sensing when display updating is paused.
Description of Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).


1. Field of the Invention
The present invention relates to a power saving method in a wireless LAN system, and more particularly, to a power saving method in a wireless LAN system conforming to IEEE802.11.
2. Description of the Related Art
Power saving in a wireless LAN system conforming to IEEE802.11 is performed in sequences illustrated in FIGS. 1A, 1B, for example, as disclosed in IEEE Std 802.11, 9.7 Frame exchange sequences Table 21 Frame sequence.
FIG. 1A is a sequence chart illustrating a sequence of operations when no data destined to a terminal station is stored in a base station. The terminal station transmits PS-Poll, which is a control packet for prompting the base station to transmit data, to the base station for requesting the base station to transmit downlink data destined thereto after the terminal station has transitioned to an active mode, in which a transmission/reception function turns on (step 101). Upon receipt of PS-Poll without error, the base station transmits a successful reception notification signal ACK (step 102). The terminal station transitions to a doze state in which the transmission/reception function turns off after it has completed the transmission of ACK.
FIG. 1B is a sequence chart illustrating a sequence of operations when data destined to the terminal station has been stored in the base station. The terminal station transmits PS-Poll to the base station, after it has transitioned to the active mode, for requesting the base station to transmit downlink data destined thereto (step 111). Upon receipt of PS-Poll without errors, the base station transmits a data frame (step 112). Upon receipt of the data frame without errors, the terminal station transmits ACK (step 113). The terminal station transitions to the doze state after it has completed the transmission of ACK.
FIG. 2 is a flow chart illustrating the operation of the terminal station in the foregoing situation. As the terminal station starts a receiving operation, it transitions to an active state (step 201). Next, the terminal station transmits PS-Poll to the base station for requesting the base station to transmit data destined to the terminal station (step 202). Next, the terminal station determines whether a response to PS-Pall from the base station is ACK or data (step 203). If the terminal station fails to receive either ACK or data, the terminal station again transmits PS-Pall (step 202). Upon receipt of ACK, the terminal station determines that there is no data destined thereto stored in the base station, and transitions to the doze state (step 205). Upon receipt of data, the terminal station transmits ACK to the base station (step 204), and transitions to the doze state (step 205), followed by termination of the receiving operation.
In the foregoing sequence of operations, when data destined to the terminal station is stored in the base station, the base station returns a data frame when it receives the PS-Poll signal from the terminal station without errors. However, conventional general wireless LAN base stations are often configured to return ACK to a terminal station in response to PS-Poll from the terminal station irrespective of the presence or absence of data to the terminal station. This is because it takes long time to complete the transmission of the data frame so that the base station informs, as a temporary measure, the terminal station that the PS-Poll signal has been received without errors. IEEE802.11 also approves that ACK is returned.
FIGS. 3A, 3B illustrate sequence charts when a base station returns ACK to a terminal station in response to PS-Poll from the terminal station irrespective of the presence or absence of data destined to the terminal station.
FIG. 3A is a sequence chart when no data destined to a terminal station is stored in the base station. The terminal station transmits PS-Poll to the base station after it has transitioned to the active mode for requesting the base station to transmit downlink data destined thereto (step 301). Upon receipt of PS-Poll without errors, the base station transmits ACK (step 302).
FIG. 3B is a sequence chart when data destined to a terminal station is stored in a base station. The terminal station transmits PS-Poll to the base station after it has transitioned to the active mode for requesting the base station to transmit downlink data destined thereto (step 311). Upon receipt of PS-Poll without errors, the base station transmits ACK to the terminal station (step 312). When data destined to the terminal station is stored in the base station, the base station further transmits a data frame to the terminal station (step 313). Upon receipt of the data frame without errors, the terminal station transmits ACK (step 314).
In this way, data communications in a power save mode in a general wireless LAN differs in a frame sequence chart between the terminal station and base station depending on the presence or absence of data destined to the terminal station stored in the base station. Then, as illustrated in FIGS. 3A, 3B, when the base station returns ACK to the terminal in response to PS-Poll from the terminal station irrespective of the presence or absence of data destined to the terminal station, the terminal station experiences difficulties in determining whether to transition to the doze state when no data is stored in the base station, resulting in difficulties in a reduction in power consumption. This is because the terminal station cannot determine the presence or absence of data destined thereto at the time it receives ACK, and therefore cannot promptly transition to the doze state. This is because the terminal station does not know whether or not data destined thereto is present in the base station at the time it receives ACK. Therefore, even if there is no data destined to the terminal station, the terminal station cannot transition to the doze state immediately after the receipt of ACK.


In recent years, a network facsimile device for communicating facsimile image information by use of electronic mail on the Internet has been developed.
The document RFC(Request For Comments) 2301˜2306 published by the organization responsible for collecting technologies relating to the Internet referred to as IETF(Internet Engineering Task Force), prescribes the technical contents of a communication protocol, etc. employed in such a network facsimile device.
In the Internet, a delivery system has been developed for delivering electronic mail to a sending terminal for confirming the delivery of electronic mail to a destination terminal. This type of e-mail is hereinafter referred to as “a delivery confirming mail”. This type of delivery confirming mail system is capable of confirming whether electronic mail has been delivered to the address of the communication partner to which it has been addressed. This is an expanded function of the electronic mail system.
In such a delivery confirming mail system, the electronic delivery confirming mail is created both when the electronic mail has been delivered to the mail address to which it was sent and when the electronic mail has not been successfully delivered to the mail address to which it has been sent. In each case, electronic delivery confirming mail is created and delivered to the communication partner which sent the electronic mail.
In the above-mentioned network facsimile device, however, there presently exists no method of surely knowing whether electronic mail which is used for carrying the image information has been delivered to the address of the communication partner to which it is to be delivered. Accordingly, other ways of confirming the delivery of the image information must be considered.
However, confirming the delivery of image information by a network facsimile device which uses e-mail delivery presents its own unique problems. For example, when the network facsimile device receives electronic mail addressed to itself, the network facsimile device performs local processing on the electronic mail. Consequently, if a delivery confirming mail were used to confirm delivery of the electronic mail sent from the network facsimile device, the network facsimile device would record and output the contents of the delivery confirming mail. However if, all of the contents of the delivery confirming mails are recorded and outputted, there arises the problem of wasteful consumption of recording paper. In addition, a user would need to be present at the network facsimile device to read the delivery confirming mail to determine whether the delivery was successful. These and other problems need to be addressed and solved.


1. The Field of the Invention
The present invention generally relates to Reliable Messaging protocols for Web Services. More specifically, the present invention provides for a mechanism that leverages characteristics of Reliable Messaging protocols for Web Services (RM-WS) for verifying and maintaining connection liveliness in a sequence session.
2. Background and Related Art
Computer networks have enhanced our ability to communicate and access information by allowing one computer or device to communicate over a network with another computing system using electronic messages. When transferring an electronic message between computing systems, the electronic message will often pass through a protocol stack that performs operations on the data within the electronic message (e.g., parsing, routing, flow control, etc.). The Open System Interconnect (OSI) model is an example of a network framework for implementing a protocol stack.
The OSI model breaks down the operations for transferring an electronic message into seven distinct layers, each designated to perform certain operations in the data transfer process. While protocol stacks can potentially implement each of the layers, many protocol stacks implement only selective layers for use in transferring data across a network. When data is transmitted from a computing system, it originates at the application layer and is passed down to intermediate lower layers and then onto a network. When data is received from a network it enters the physical layer and is passed up to the higher intermediate layers and then is eventually received at that application layer. The application layer—the upper most layer—is responsible for supporting application and end-user processing. Further, within the application layer there may reside several other layers (e.g., the Simple Open Access Protocol (SOAP) layer). Another layer incorporated by most protocol stacks is the transport layer. An example of a transport layer is the Transmission Control Protocol (TCP).
Web Services (WS) have been a driving force in advancing communications between computing systems and are turning the way we build and use software inside-out. Web Services let applications share data and—more powerfully—invoke capabilities from other applications without regard to how these applications where built; what operating systems or platform they run on; and what devices are used to access them. Web Services are invoked over the Internet by means of industry-standard protocols including SOAP, XML (extensible Markup Language), UDDI (Universal, Description, Discovery and Integration), WSDL (Web Service Description Language), etc. Although Web Services remain independent of each other, they can loosely link themselves into a collaborating group that performs a particular task.
Current WS technologies offer direct SOAP-message communication between an initiator (e.g., a client) and an acceptor (e.g., a service). In the common bi-directional messaging case, a SOAP request message is sent from the initiator to the acceptor and a SOAP reply message is sent in response thereto. Another communication variant between endpoints is unidirectional message exchange, where the initiator sends a message to the acceptor with no response.
A key benefit of the emerging WS architecture is the ability to deliver integrated, interoperable solutions. Because, however, Web Services provide various services from different business, originations, and other service providers via unreliable communication channels such as the Internet, reliability of WS becomes an increasing important factor. Reliability of WS is impacted by several factors including but not limited to, the reliability of the Web Service end points; reliability characteristics of the communication channel over which the Web Services are accessed; performance and fault-tolerance characteristics; and the extent to which Web Services can handle concurrent client access.
There have been attempts at accomplishing reliable messaging of Web Services by choosing a reliable transport protocol over which the messages (e.g., SOAP messages) are exchanged between endpoints. For example, a reliable messaging transport such as message-queues can be used to deliver messages reliably between initiators and acceptors. Messing-queuing communication technologies enable applications on different systems to communicate with each other by sending messages to queues and reading messages from queues that are persisted across failures for reliability.
Although queuing systems offer a transport that can be used to carry SOAP messages reliably, there are several drawbacks to such systems. For instance, these systems offer solutions for an asynchronous operation where the requests (and possibly their responses) are transferred and processed with isolation. Accordingly, these systems are typically heavyweight in terms of resources; involving multiple intermediaries with durable transacted message stores and with considerably more complexity in deployment, programming model and management. All of this is unnecessary for reliable direct communication, and detracts from the goal of minimizing latency. Further, the program model does not directly support request-response style programming or sessions. Accordingly, the queued communication model is different from the current “interactive” Web Services model, and does not address critical “connected” scenarios and “interactive” applications. For example, it is not well suited for cases where a response is expected in a timely manner, or for cases where distributed-transaction-context need to be shared between initiator and acceptor.
There have also been attempts at defining reliable transfer layers over fundamentally unreliable transport protocols, e.g., reliable HTTP or HTTPR. A common problem, however, that plagues this solution—as well as the queuing solution—is that reliable messaging can be achieved only if the specific reliable transport protocol is used for communication between the initiator and the acceptor. The fundamental nature of Web Services calls for independence from specific vender platform, implementation languages and specific transport protocols. In a generic case, an initiator may not be able to transmit a message directly to an acceptor using a particular protocol (e.g., acceptor does not support the protocol) or the message may need to pass through multiple hops after leaving the sending node prior to arriving at that destination node. Depending on the nature of the connectivity between the two nodes involved in a particular hop, a suitable transport protocol that does not offer reliable messaging characteristics may have to be chosen.
Intermediaries may also exist at different levels in the protocol stack; and therefore not offer full end-to-end reliability. For example, transport protocols may offer reliability across lower level intermediaries (e.g., IP level intermediaries—e.g., IP routers). The transport protocol may end, however, at a SOAP intermediary or application layer. Accordingly, the transport protocol may not be able to offer reliability across that intermediary, i.e., no end-to-end reliability across the application layer.
More recently, various Reliable Messaging protocols for Web Services (hereinafter referred to as “RM-WS protocols”), e.g., WS-ReliableMessaging, offer solutions to the above identified-deficiencies of current reliable messaging systems. These protocols are transport agnostic connected protocols that allow messages to be delivered reliably between end-point applications in presences of software component, system or network failures. Accordingly, RM-WS protocols offer solutions for reliable, end-to-end, session-oriented communication between an initiator and an acceptor.
These RM-WS protocols are akin to TCP in that TCP offers reliable, exactly-once, in-order delivery of a stream of bytes from a TCP sender to TCP receiver across Internet Protocol (IP) routers and multiple networks. Reliable Messaging protocols for WS offer the same and more for messages (note: the unit of transfer is a message, not a byte or a collection of bytes as is the case for TCP wherein the size of the bytes is determined by the available payload space in the IP packet) across multiple intermediaries (including SOAP level intermediaries), transports and connections. Although TCP and RM-WS protocols are both “reliable” protocols, because RM-WS resides at the application or SOAP layer in the OSI model, RM-WS protocols provide for reliable messaging regardless of the transport protocol used to transfer the data. Accordingly, RM-WS protocols are not tied to a particular transport or other protocol used to transfer message between endpoints.
Although a few RM-WS protocols have been around for some time there are still several drawbacks and deficiencies of these protocol specs. For example, these RM-WS protocols do not provide a way for verifying the connectivity of an established sequence session. Further, the specifications do not provide for a way to maintain the liveliness of a connection and/or to extend the sequence session in the absence of an exchange of messages over an inactivity timeout period. Accordingly, there exists a need to verify and maintain connection liveliness for systems that use a RM-WS protocol.


In parametric internal model-based control (IMC), a controller may be used to control a process where the controller includes a model of the process. The accuracy of the model drives the performance of the controller. IMC is also known in the art as model predictive control (MPC) or simply as model-based control (MBC). For purposes of this disclosure, the term IMC will be used.
FIG. 1 shows a representation of a control system 10 that includes a model 12 of an integrating process 14 that may be controlled with a controller 16 by a predictive control technique that is represented by an inverted version of the model 12 (realizable model inverse) and an associated filter. Parameters of the model are used to calculate, or predict, a future process variable (PV), and generate a control output (CO) responsive to a given set point. But, as will be explained in greater detail below, modeling the behavior of an integrating process that may have one or more poles at origin leads to computational difficulties.
For any non-zero disturbance (e.g., input disturbance d1 and/or output disturbance d2), the predicted process variable (also known as a controlled variable or CV) will grow without bound due to the integrating nature of the conventional implementation of the model 12 and associated inverted model. The same holds for any non-zero control output CO (also known as a manipulated variable) as the model prediction of the future state of PV also will grow without a bound.
The model output under the forgoing conditions is represented in the graphs of FIGS. 2a and 2b, which share the same scale for the time axis. In FIG. 2a, the control output CO is graphed. As illustrated, a step change to the control output CO is made at a given time. As will be appreciated, the control output CO change is the input value to the process model 12 and the process 14. The predicted process variable that is output by the model 12 is graphed in FIG. 2b.
A dead time D is a measurement of how long the process takes to start to respond to the CO change and may be defined by the amount of time that elapses from the change in control point to when the predicted process variable exceeds a noise threshold defined by a noise band. A time constant (or lag time) may be used as an indicator of how long the process takes to reach steady state after the dead time. For an integrating process, the time constant value may be the amount of time that elapses from the end of the dead time to when the slope of the predicted process variable achieves 63% of the slope of the steady state PV. 95% of the slope of the steady state PV may be achieved after three time constants.
As illustrated, using an integrating process model, the value for the predicted process variable will grow without bound. A maximum slope of the predicted process variable curve (or PV maximum slope) may be determined and the gain (k) may be defined by the PV maximum slope divided by the CO change. The unbounded increase in predicted process variable is not necessarily a design issue for the control system 10, but represents a computational and numerical issue.
Three common solutions exist, but each have drawbacks. The first solution is to convert output disturbances (or modeling errors) to an equivalent input disturbance, such that disturbances and errors that are input to the model are mathematically zeroed in the steady state. The second solution is to reinitialize the state of the predicted process variable from time to time to reduce the occurrence of a numerical overflow. The third solution is to use an internally stable algorithmic internal model control (AIMC) of a two degree of freedom IMC.
While these solutions improve the behavior of the model, they all introduce design and computational complexities. Moreover, for an integrating process, the design of an internal model-based controller is complicated by the introduction of a higher order filter as will be demonstrated below.
With continued reference to FIG. 1, conventional representations of a first order integrating process will now be described. Under these representations, the integrating process 14 may be represented by equation 1A and the model 12 of the process may be represented by equation 2.
                                          G            p                                          (            s            )                          =                              k            s                                          ⅇ                          -              DS                                                          Eq. 1A                                                      G            m                                          (            s            )                          =                                            k              ^                        s                                          ⅇ                                          -                                  D                  ^                                                          S                                                          Eq. 2
The steady state process gain is represented by k in equation 1A and an estimated steady state process gain is represented by {circumflex over (k)} in equation 2. Similarly, D is the process dead time and {circumflex over (D)} is an estimated dead time. In each equation, a Laplace variable is represented by S.
The controller 16 may be represented by equation 3, in which Gm+−1 is an invertible portion of the model 12 (equation 2) and F(s) is a filter that is designed to make the controller represented by Gc(s) realizable. The filter specifies a desired response for the process variable PV (referred to as a desired trajectory of PV).Gc(s)=Gm+−1·F(s)  Eq. 3
A controller computation round-off error is shown in FIG. 1 as d3, which represents a rounding error. While the rounding error may be very small, the rounding error may still lead to a numerical instability issue, as described below.
The system 10 of FIG. 1 may be simplified into the forms illustrated in FIGS. 3 and 4. If, in FIG. 3, a perfect model 12 is obtained for a first order process 14, Gm(s) will equal Gp(s), and then both Gm(s) and Gp(s) may be represented by equation 1A. If a first order filter F(s) equaling 1/(εs+1) is used, equation 3A results, where ε is a filter time constant.
                              G          c                =                                            G                              m                +                                            -                1                                      ·                          F                                            (                s                )                                              =                      s                          k                                            (                                                      ɛ                                                                                s                                    +                  1                                )                                                                                Eq          .                                                    3                        A
As indicated, Gm+ is the invertible portion of the model and is equal to k/s. In FIG. 4, GIMC may be considered the combination of Gc and Gm and represents an internal model-based controller 16′. GIMC may be expressed as equation 4.
                              G          IMC                =                                            G              c                                      1              -                                                G                  c                                                                  G                  m                                                              =                                                    s                                  k                                                        (                                                                  ɛ                                                                                s                                            +                      1                                        )                                                                              1                -                                                      ⅇ                                          -                      DS                                                                                ɛ                                                                                s                                        +                    1                                                                        =                          s                              k                                                  (                                                            ɛ                                                                                s                                        +                    1                    -                                          ⅇ                                              -                        DS                                                                              )                                                                                Eq        .                                          4
In equation 5A, the process variable PV is expressed using a three term equation that represents a dynamic relationship among the value at the input to the controller 16′ (first term where SP is the set point), the value at the input to the process 14 following introduction of an input disturbance d1 (second term) and the value at the output of the process following introduction of an output disturbance(s) d2 (third term).
                              PV                                (            s            )                          =                                                                              G                  IMC                                                                  G                  p                                                            1                +                                                      G                    IMC                                                                          G                    p                                                                                SP                    +                                                    G                p                                            1                +                                                      G                    IMC                                                                          G                    p                                                                                d              1                                +                                    1                              1                +                                                      G                    IMC                                                                          G                    p                                                                                d              2                                                                    Eq          .                                                    5                        A
The second term of equation 5A corresponds to an input disturbance to the process 14 and it is desirable for this term to be zero at steady state. If the second term is not zero, a steady state error occurs. By applying a step input for the set point (or set point change) an analysis of how PV will behave may be made. One may represent the step input as r, such that SP(s) equals (1/s)r and equation 6 follows from equation 5A.
                                                                        t                                                  →                  lim                                                                  ∞                                                                                PV                                                              (                      t                      )                                                                                =                              s                                                  →                  lim                                                                  0                                                                                G                        IMC                                                                                G                        p                                                                                1                      +                                                                        G                          IMC                                                                                G                          p                                                                                r                                                                                =                              s                                                  →                  lim                                                                  0                                                                                ⅇ                                                  -                          DS                                                                                (                                                                              ɛ                                                                                s                                                    +                          1                          -                                                      ⅇ                                                          -                              DS                                                                                )                                                                                1                      +                                                                        ⅇ                                                      -                            DS                                                                                (                                                                                ɛ                                                                                s                                                        +                            1                            -                                                          ⅇ                                                              -                                DS                                                                                )                                                                                r                                                                                =                                                s                                                        →                    lim                                                                          0                                                                                ⅇ                                                  -                          DS                                                                                ɛ                                                                                s                                                +                        1                        -                                                  ⅇ                                                      -                            DS                                                                          +                                                  ⅇ                                                      -                            DS                                                                                r                                                  =                r                                                                        Eq        .                                          6
It may be observed that for a change in the set point SP variable, there is a direct correlation in the process variable PV attained at steady state. But if a step input disturbance (e.g., d1(s) equaling d1/s) is introduced, a steady state error in PV results as indicated by equation 7.
                                                                        t                                                  →                  lim                                                                  ∞                                                                                PV                                                              (                      t                      )                                                                                =                              s                                                  →                  lim                                                                  0                                                                                G                      p                                                              1                      +                                                                        G                          IMC                                                                                G                          p                                                                                d                    1                                                                                =                              s                                                  →                  lim                                                                  0                                                                                k                                                                                ⅇ                                                      -                            DS                                                                                s                                                              1                      +                                                                        ⅇ                                                      -                            DS                                                                                (                                                                                ɛ                                                                                s                                                        +                            1                            -                                                          ⅇ                                                              -                                DS                                                                                )                                                                                d                    1                                                                                =                              s                                                  →                  lim                                                                  0                                                                                k                                                                    (                                                                              ɛ                                                                                s                                                    +                          1                          -                                                      ⅇ                                                          -                              DS                                                                                )                                                                                s                                                                    (                                                                              ɛ                                                                                s                                                    +                          1                          -                                                      ⅇ                                                          -                              DS                                                                                +                                                      ⅇ                                                          -                              DS                                                                                )                                                                                d                    1                                                                                =                                                s                                                        →                    lim                                                                          0                                                                                k                                                                                ɛ                                                +                                                  kD                                                                                ⅇ                                                          -                              DS                                                                                ɛ                                                                                s                                                +                        1                        +                                                  ɛ                                                                                s                                                                                d                      1                                                                      =                                                                            (                                                                        k                                                                                ɛ                                                +                                                  k                                                                                D                                                                    )                                                                                d                      1                                                        ≠                  0                                                                                Eq        .                                          7
It may further be observed that for a step output disturbance where d2(s) equals d2/s, the third term of equation 5A advantageously goes to zero as demonstrated by equation 8.
                                                                        t                                                  →                  lim                                                                  ∞                                                                                PV                                                              (                      t                      )                                                                                =                              s                                                  →                  lim                                                                  0                                                                                1                                          1                      +                                                                        G                          IMC                                                                                G                          p                                                                                d                    2                                                                                =                                                s                                                        →                    lim                                                                          0                                                                                ɛ                                                                                s                                                +                        1                        -                                                  ⅇ                                                      -                            DS                                                                                ɛ                                                                                s                                                +                        1                        -                                                  ⅇ                                                      -                            DS                                                                          +                                                  ⅇ                                                      -                            DS                                                                                =                0                                                                        Eq        .                                          8
It may be concluded that with a first order filter and a perfect model, the IMC controller 16′ (FIG. 4) will have a steady state error for a step input disturbance. To reduce or eliminate the steady state error for a step input disturbance, a complex filter F(s) may be employed. But such a filter is difficult to implement in an actual controller used to control an actual integrating process. In addition, the model that drives the controller still contains a numerical issue in that the value output by the model will grow without bound due to the exponential component of the integrating model.


An extremely fine pattern of a solid element such as large-scale semiconductor integrated circuit or the like is formed by using chiefly a reduction projection exposure method that is one of optical lithography methods. This method is a method of reducing and transferring a mask pattern formed by a photomask or a reticle (called a mask hereinafter), onto a substrate by use of an imaging optical system.
Improvement of resolution in the reduction projection exposure method is advanced by high numerical aperture in the imaging optical system and short wavelength of exposed light. However, since there are needs of more extreme fineness for least process size of the solid element than the above-mentioned improvement, a deformed illumination exposure method or a phase shift mask exposure method, so-called a super resolution exposure method is developed and applied.
The phase shift mask exposure method includes, for example, a Levenson type phase shift mask, a halftone type phase shift mask, an auxiliary pattern arrangement type phase shift mask, and the like. The Levenson type phase shift mask is a mask generating a phase difference of 180 degrees between light beams that permeate regions between adjacent apertures (light permeating region) on the mask. The Levenson type phase shift mask also has an effect on further improvement of the resolution thereof within regions in which pattern-arranged pitches are extremely fine. For example, if a Levenson type phase shift mask is used, a reduction projection exposure method using KrF excimer laser light can eminently improve resolving characteristics even within a size region less than a least process size whose sufficient resolution is difficult to obtain in the case of use of normal masks. Further, the halftone type phase shift mask is a mask in which a halftone film is formed on a mask substrate instead of a light shield film. The halftone film has functions of making exposed light beams be permeated some per cents and of generating a phase difference of 180 degrees between exposed light beams permeating the halftone film and permeating apertures around which the halftone film is removed.
And, the auxiliary pattern arrangement type phase shift mask is a mask having such a size as not to resolve on a semiconductor wafer around a main aperture and arranging auxiliary patterns for generating a phase difference of 180 degrees between exposed light beams permeating the main aperture. The auxiliary pattern arrangement type phase shift mask can be used when mask patterns are not arranged densely. For example, in a mask pattern for transferring isolated hole patterns, there is a structure of arranging auxiliary patterns which have such a size as not to be transferred on the semiconductor wafer of a plane surface containing upper, lower, right and left side of the main aperture and which generate a shift difference of 180 degrees relative to exposed light beams permeating the main apertures. This results in improvement of a light intensity profile of the main aperture and enhancement the resolving characteristics. This method is described in Japanese Patent Laid-open No. 5-19446, which discloses a technique of disposing auxiliary patterns on an end of dense patterns and around isolated patterns in order to enhance resolution of the dense patterns end and the like. Further, for example, Japanese Patent Laid-open No. 6-123963 discloses a technique of disposing respective auxiliary patterns such that light beams permeating respective adjacent patterns do not interfere with one another, or a technique of disposing one auxiliary pattern relative to the main aperture when the auxiliary patterns are arranged between the adjacent patterns. And, for example, Japanese Patent Laid-open No. 6-289591 discloses a technique of disposing auxiliary patterns in a symmetrically shifted manner in order to enhance flexibility in arrangement of the main apertures. Further, for example, Japanese Patent Laid-open No. 8-297359 discloses a technique of making layouts of mask patterns such that one main aperture and one auxiliary pattern are handled as one unit in order to facilitate the layouts of the mask patterns. And, for example, Japanese Patent Laid-open No. 11-84625 discloses a structure of disposing main apertures, auxiliary patterns, and shifters arranged like zigzag at dense main apertures, and of arranging the auxiliary patterns at each end of memory mats.


Known optical instruments for measuring angles, such as sextants and octants, comprise support means in the form of a frame; an eyepiece mounted on the support means; a first reflector, known as a "horizon glass", mounted on the support means in alignment with the axis of the eyepiece; an adjustment member, known as an "index bar", pivotally mounted on the support means; a movable reflector mounted on the adjustment member so as to face towards the first reflector; and measuring means comprising an angularly graduated "arc" for measuring movement of the adjustment member. The support means comprise first and second arms extending divergently from a hub and interconnected at their free ends by an arcuate limb. The eyepiece and first reflector are respectively mounted on the first and second arms and the adjustment member carrying the movable reflector is pivotally mounted in the hub at the junction of the first and second arms.
To use an instrument of this type to measure the inclination of a celestial body, such as the sun or a star, it is necessary to hold the instrument with the optical axis of the eyepiece aligned with the horizon so that the horizon may be viewed through the eyepiece and a non-reflective portion of the horizon glass and then, with the pivotal axis of the hub arranged horizontally, above the optical axis of the eyepiece, to measure the angular movement of the adjustment member from a datum position in which the movable reflector is parallel to the first reflector to a position in which light from the celestial body is reflected from the movable reflector to the first reflector and back along the optical axis of the eyepiece so that the celestial body can be viewed through the eyepiece. This angular movement is equal to half the angle of inclination of the celestial body from the axis of the eyepiece. This is consistent with the law of optics whereby the angle between the first and last directions of a beam of light which is reflected twice, by two plain reflective surfaces, is twice the angle between the two reflective surfaces. By reference to navigational tables, it is possible to establish from such inclinations the positions from which measurements have been made.
Although an octant, in which the first and second arms are inclined at 45.degree., is capable of measuring 45.degree. movement of the adjustment member and therefore 90.degree. of inclination from an axis extending from the eyepiece to the horizon, this is not sufficient for measuring all inclinations if the instrument is used by an operator standing on an elevated platform such as the bridge of a ship. In this case, the axis extending from the eyepiece to the horizon dips below horizontal and so the maximum elevation which can be measured is less than vertical. To overcome this disadvantage, it is necessary to use the more expensive sextant in which the first and second arms are inclined at 60.degree. and which is capable of measuring inclinations of up to 120.degree. from the optical axis of the eyepiece.
In any case, to be of value, conventional sextants and octants have to be accurately made and are thus often too expensive for all but the most serious and professional navigators. Moreover, these instruments are particularly difficult to use, and cannot be used at all when the horizon is obscured by haze or at night. The elevations of stars must therefore be measured during twilight, at dusk and dawn, when both the stars and the horizon are visible. Clearly, on very many occasions when the horizon is indistinct, the great precision of navigational instruments such as sextants and octants is unnecessary in view of the unavoidable error in aligning the optical axis of the eyepiece with the horizon.
One known technique for modifying a conventional sextant or octant so as to make it possible to measure inclinations when the horizon is not visible is to provide the instrument with a spirit level and complex optical means which enable an operator to view an artificial horizon when the instrument is held so that the optical axis of the eyepiece extends horizontally. However, the resultant instrument, known as a "bubble sextant", does not work satisfactorily and has never been widely accepted by navigators. The modification increases the complexity of the instrument with attendant difficulty in keeping the instrument in accurate operating adjustment, and the cost is considerably higher than for conventional sextants and octants.


The present invention relates to an X-Y input device, and more particularly to an X-Y input device suitable for use as an input device associated with a graphic display apparatus.
Graphic display apparatus basically include a display screen, a display controller, a data channel, and an input device which may be of various types. One known input device is a "joystick" having a lever supported by a gimbal mechanism and tiltable by the operator in any direction. A control device detects the direction and angle of tilt of the lever and generates voltages or digital signals indicative of coordinate values in X and Y directions. This type of input device is disadvantageous however in that the range of angular movement of the lever is limited and data signals entered by the operator are relatively unstable.
In an effort to eliminate the above shortcomings, there has in recent years been developed an input device called a "mouse." One type of the mouse has a rotatable member such as a steel ball, and first and second driven rollers held in contact with the ball are rotated in response to rotation thereof. The first and second driven rollers have their axes of rotation extending substantially perpendicularly to each other. The mouse also includes first and second angle detector means often comprised of variable resistors or encoders for separately detecting the angles of rotation of the first and second driven rollers. The ball, first and second driven rollers, and first and second angle detector means are all housed in a casing.
The casing has an opening defined in its bottom with the ball partly projecting through the opening. In use, the casing is held by the operator to place the ball against a given base or surface. By moving the casing to cause the ball to roll on the surface in any desired direction, the first and second driven rollers are rotated about their own axes through angles dependent on the rolling movement of the ball. The directions and angles of rotation of the driven rollers are converted by the first and second angle detector means into voltages or digital signals corresponding to the rolling movement of the ball representative of coordinate values in X and Y directions. The generated signals are then entered into a display apparatus.


Increasing amounts of available petroleum feedstocks correspond to natural gas sources or other methane-containing sources. The increased availability of methane and/or small hydrocarbon petroleum sources can potentially have increased value if efficient methods can be identified for conversion to larger compounds.
One option for converting methane (and other small hydrocarbons) to other compounds is to reform the methane to form H2 and/or CO (i.e., synthesis gas). Both steam reforming and dry reforming are known, but each type of reforming poses a variety of challenges. In particular, both types of reforming processes are prone to formation of coke on the reforming catalyst. This is especially true when the natural gas feed contains elevated levels of CO2 and/or C2+ hydrocarbon molecules, such as ethane or propane. In such cases, conventional reforming processes employ additional gas separations processes to reduce the CO2 content to acceptable levels—about 18-20% for steam reforming processes and much lower, about 5%, for autothermal reforming processes—or a prereformer to convert C2+ hydrocarbons to carbon monoxide and hydrogen.
These pretreatments increases the capital and operating expenses of reformning processes. Moreover, natural gas streams with high amounts of CO2 and/or C2+ hydrocarbons are more likely to be used as low cost fuels rather than for the production of high margin products through their conversion into synthesis gas, and are thus cost suppressed.
U.S. Pat. No. 8,454,911 describes methods of using a reverse flow reactor for reforming of methane to form acetylene.
U.S. Pat. No. 7,217,303 describes methods for pressure swing reforming of a hydrocarbon fuel in the presence of steam to form hydrogen. The reforming step is described as having a peak temperature of 700° C. to 2000° C.
U.S. Pat. No. 7,815,873 describes methods for reforming of a hydrocarbon fuel in a reverse flow reactor configuration. The reforming step is described as having a temperature of at least 1000° C.


This disclosure relates to computer animation and computer generated imagery. More specifically, this disclosure relates to systems and methods for creating and using hierarchies of models for rigging.
Computer-generated imagery (“CGI”) is a process of using computers to convert specifications of objects, things, lights, effects, etc. into images. CGI might be used for generating one image, for example, of a teapot with one light source, or might be used to generate an animation, a sequence of images such as might be used for a feature-length film.
Many computer graphic images are created by mathematically modeling the interaction of light with a three dimensional scene from a given viewpoint. This process, called rendering, generates a two-dimensional image of the scene from the given viewpoint, and is analogous to taking a photograph of a real-world scene. Animated sequences can be created by rendering a sequence of images of a scene as the scene is gradually changed over time. A great deal of effort has been devoted to making realistic looking rendered images and animations.
Some animation might be done by manually painting each image, but with the wide use of computers, it is common, for movies or other features, to have a user (e.g., an animator or other skilled artist) specify geometric descriptions of models or other objects, such as characters, props, background, or the like that may be rendered into images. An animator may also specify poses and motions for objects or portions of the objects. In some instances, the geometric description of objects may include a number of animation variables (avars), and values for the avars. As an example, a simple character might comprise a model that comprises a fixed body, two arms and two legs, with four joints where the arms and legs join the body and can be moved. An animation variable for such a model might be the angle between the body and the right arm. The animator could “pose” this model by placing the body at a location and an orientation in the virtual three-dimensional space, then specifying the four angles (two arm rotations and two leg rotations). This posing might be done by the animator typing in values for each degree of freedom and viewing a rendering of the result.
In such a simple case, entering in a few values is not a problem, but many models are much more complicated. For example, a character model might include a movable body, arms, elbows, fingers, facial muscles, etc., all with their own degrees of freedom. To simplify the entry of the animator's desired pose and/or movements, a user interface with “handles” or “widgets” for avars might be provided. As an example, a user interface might display a rendered character and overlay yellow squares that the animator can drag and move to indicate movements desired by the animator. Internally, the animation editing software that presents the user interface to the user and receives the animator's inputs could translate a “drag-handle” operation into a change in value of an avar.
In some animation terminology, a model refers to a collection of elements that together form an object that is presented in a scene and may have some degrees of freedom. The number of degrees of freedom may depend on the type of object. A model for a building might have a degree of freedom as to how a door opens or closes and where the building is located, but that model—except perhaps in some stories—might not be expected to have a degree of freedom that allows a central spine to rotate and bend.
A rigging for a model refers to the user interface (logical or actual) for exercising the degrees of freedom. Using the rigging, an animator can specify a pose of the model for a still image and/or specify how the model is to move from pose to pose in an animation. Rigging is not part of the displayed scene, although there are user interfaces provided to animators that illustrate parts of the rigging, such as when animation is being edited. Models can be given various controllers, animation variables, and handles for an animator to manipulate various locations of the object's topology to create complex movements and motions.
For some models, a bone/joint system can be set up to deform various locations of the object's topology. For example, the bone/joint system can be connected to foot, ankle, knee, hip, and other leg locations of a humanoid model to provide the structure to make the humanoid model walk. Other types of information may also be “hung” on the object's topology to add further realism or additional control for the animator. In other words, information may be associated with a vertex, edge, span, or face of the mesh that forms to the object's topology. However, the above processes can be very involved and time consuming to simply generate a single model.
Additionally, a typical feature-length animation may require hundreds to thousands of models. This increases the production time and cost of the animation if each model may be required to be hand-created and setup. One possible solution can be to hand copy the information from one model to another. However, this process still requires an animator to place or “hang” the copied data onto the correct position of the new objects topology. Rarely is each character exactly the same, so each character's topology can have some differences that the animator has to deal with.
For example, an animated feature film might involve classes of objects or characters, with hierarchical subclasses. For example, there might be class of characters such as humans, with subclasses for warriors, elderly humans, tall humans, short stocky humans, children, adults, etc. and subclasses of subclasses, such as injured tall humans, etc. It could be that each of the different subclasses have separate models and separate rigging, but that can be a lot of work for an animation team.
Accordingly, what is desired are improved methods and apparatus for solving some of the problems discussed above, while reducing further drawbacks, some of which are discussed above.


Permanent seat licenses, also known, for instance, as personal seat licenses, Stadium Builder licenses (SBL), Charter Ownership agreements (COA), Charter Seat licenses (CSL), and Preferred Access Speedway Seating (PASS), are a relatively recent innovation wherein, for example, sports teams sell “seat licenses” to fans desiring admission tickets to team events. Generally, the seat license for a particular seat within the stadium or arena enables and/or requires the holder of that license to purchase season tickets to team events. The season ticket, in turn, gains the holder admission to individual team events during the course of the season where the holder is able to sit in the particular seat. However, permanent seat licenses (referred to herein as “PSL's”) are also an important source of revenue for the sports team issuing the PSL's. This revenue can be used by the team to, for example, subsidize the construction of new facilities or for other purposes requiring capital outlay. Note that the PSL's may be issued by entities other than just sports teams. For example, the sports team may often act in partnership with a government entity, where the partnership issues the PSL's. In other instances, the government entity may build, own, and operate the stadium independently of the sports team and may thus issue the PSL's independently thereof. Further, the venue may be owned by an entity separate from both the sports team and the government entity and it is the separate entity which issues the PSL's. Note further that the PSL concept as described herein may be applicable to venues for other events besides sports such as, for example, theaters or the like. Thus, it will be understood by one skilled in the art that the PSL concept may have wide and varied applicability.
PSL's are generally offered directly to the public by the sports team (referred to herein as the “issuer”). These PSL's often have prices ranging from hundreds to many thousands of dollars. Sometimes, for a variety of reasons, such as moving from the area or losing interest in the team, holders may sometimes wish to sell their PSL's after buying them from the issuer. A problem herein lies that, since a PSL is a niche commodity, there is no established resale market for the product. In some instances, computer bulletin boards and newspaper classified ads are utilized to find a subsequent buyer. However, such transactions are often laden with uncertainty for both the seller and the buyer. For instance, due to the cost of the PSL's, a buyer may often have to procure financing, which may delay the transaction. If the seller is desperate to sell the PSL's, he may arrange to finance all or part of the sale to the buyer, which may further lead to uncertainty for the seller recouping his money from the buyer. Likewise, the buyer is faced with uncertainty as to, for example, whether the seller is the rightful owner of the PSL's or whether the seller will deliver the PSL's upon the buyer paying the purchase price. Sometimes, the buyer may be faced with the uncertainty that the PSL's correspond to seats that do not have the view of the playing field that the buyer desires or that the seats corresponding to the PSL's have a view that may adversely affect the value of the PSL's. In other instances, the PSL's may be offered for sale by the seller independently of the current season's tickets, wherein the buyer would not be able to obtain tickets until the following season. This situation may often not be revealed to the buyer, or the buyer may forget to inquire about this detail, until the transaction has been completed.
The PSL transaction may further include mutual uncertainties for both the buyer and the seller. For instance, since there is no established market, it is often difficult for both the seller and the buyer to ascertain a going market price for the PSL's. Such a market price may also be affected by performance factors with the team itself. For example, PSL's may rise significantly in price if the team has come off a successful championship season or has recently built a new stadium or arena. Conversely, the value of a PSL may drop significantly if the team is on a losing streak or is otherwise forecast to perform poorly in the future. In addition, there may be instances where the transaction between the buyer and the seller occurs over a distance and the parties cannot meet in person. In these instances, the uncertainties facing both the buyer and seller as to the reliability of the transaction may take on a greater significance. Further, the issuer typically maintains records of the current ownership of the respective PSL and the seller and/or the buyer may be required to notify the issuer of the ownership change at the time of the transaction, as well as to pay an associated fee for the transfer. Issuer requirements with regard to the transaction may vary between issuers and may also comprise a procedure which is unknown to the parties.
Thus, there exists a need for a medium for buying and selling PSL's in which reasonable assurances are provided to both the buyer and the seller concerning important aspects of the transaction, for example, that the seller is the rightful owner of the PSL and that the buyer is capable of paying the purchase price. Such a medium should also desirably be able to inform the parties of at least a best estimate of a current market price for the PSL's, be able to let the buyer evaluate the views from the corresponding seats, and be able inform the buyer and seller as to the transaction requirements imposed by the respective issuer. It may also be desirable for the medium to incorporate provisions for facilitating the transaction wherein the seller can submit the PSL and the buyer can submit the corresponding remittance to a trusted intermediary. The medium should also desirably be able to account for the current season's tickets corresponding to the PSL together with or independently of the sale of the PSL.


A common cause of failure of implanted biomedical devices is infection. The attachment of bacteria to medical implants and in-dwelling catheters, and the proliferation of such bacteria, is a major cause of infection during or after the implantation process. Treating an implant with antibiotics has not proven very effective to combat infections, and has sometimes resulted in the development of resistant strains of bacteria.
Silver coatings are effective to combat infections; however, silver coatings tend to cause tissue irritation, largely due to excessively rapid release of the silver into the surrounding tissues.
An antimicrobial coating for a medical implant is needed which has hardness and low friction properties, and that will result in a slow, long-term release of antimicrobial metal atoms into the body in order to prevent infection.


The flexible Ethernet (FlexE) combines some technical features of the Ethernet and a transport network (for example, an optical transport network (OTN), and a synchronous digital hierarchy (SDH)), and is an important milestone in the evolution of an Ethernet technology. With emergence of a flexible Ethernet technology, Ethernet physical interfaces show virtualization characteristics. A plurality of Ethernet physical interfaces may be bonded together, to support several virtual logical ports. For example, a 400-gigabit (400G) flexible Ethernet physical interface group obtained by bonding four 100-gigabit Ethernet (100GE) physical interfaces may support several logical ports.
The Ethernet physical interface is an asynchronous communications interface, and is allowed to have a clock frequency difference of ±100 ppm (one ten-thousandth). For example, in 10GE, for two physical interfaces whose nominal bandwidths are 10 G, one bandwidth may be one ten-thousandth larger than the nominal value, and the other bandwidth is one ten-thousandth smaller than the nominal value, that is, 10G*(1+0.0001) and 10G*(1−0.0001). A clock frequency at the logical port inherits a clock frequency characteristic on the physical interface, and therefore the logical port also has a difference of 100 ppm. For example, actual bandwidths of two logical ports that are formed by different physical interfaces or physical interface groups and whose nominal bandwidths are 25 G may be approximately 25G*(20460/20461)*(1+0.0001) and 25G*(20460/20461)*(1−0.0001) when overheads of timeslot division and timeslot management in the flexible Ethernet are considered. When the flexible Ethernet is used to bear a service, idle-code-block (Idle) insertion or deletion needs to be performed hop by hop, to adapt a service rate to a bandwidth rate difference between the service and the physical interfaces or the logical ports. FIG. 1 is a schematic diagram of service transport in the flexible Ethernet in the prior art. As shown in FIG. 1, when a service between customer devices Ca and Cb is borne by using flexible Ethernet devices Pa, Pb, and Pc, the Pa, the Pb, and the Pc needs to perform idle-unit insertion or deletion.
However, idle-code-block insertion or deletion causes loss of a clock frequency and time phase information of the service, that is, the clock frequency and the time phase information of the service cannot be transparently transported, and consequently the clock frequency and the time phase cannot be synchronized between a source network device and a sink network device of the service.


1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a printer and a facsimile machine, and more particularly, to an image forming apparatus which corrects skew feeding of a sheet while conveying the sheet, and which conducts positioning of a side edge (end) of the sheet in a width direction intersecting with a sheet conveying direction.
2. Description of Related Art
Generally, image forming apparatuses of an electrophotographic system, an offset printing system and an ink-jet system are known. As image forming apparatuses using the electrophotographic system, image forming apparatuses of various systems are known, such as an image forming apparatus of a direct transfer system which transfers a toner image from a photosensitive drum directly to a sheet, and an image forming apparatus of an intermediate transfer system which once transfers a toner image to an intermediate transfer member and then transfers the toner image to a sheet. As image forming apparatuses using the electrophotographic system, an image forming apparatus of a tandem system in which a plurality of image forming portions is arranged, and an image forming apparatus of a rotary system in which a plurality of image forming portions is cylindrically arranged are known.
In recent years, in image forming apparatuses of the electrophotographic system, making full use of a merit that a plate is not formed, apparatuses targeting a printing market of small copies are provided. In order to be accepted by such a light printing market, high velocity (high productivity) and high image quality must be achieved in various kinds of materials, and a requirement for sheet conveying precision is increased. An image position precision with respect to a sheet is most required to be high, an image position deviation of front and back when images are formed on both surfaces is also included. There is a method for adjusting a position of an image with respect to a sheet, but a method for adjusting a sheet with respect to an image predominates.
The precision of an image position is determined by registration of a sheet in a sheet conveying direction, registration of a sheet in a width direction intersecting with the sheet conveying direction, magnification and skew feeding. Among them, it is difficult to correct the skew feeding of a sheet by electrical control. For example, if skew feeding of a sheet is detected and an image which inclines corresponding to the skew feeding is formed, it is possible to correct an image position with respect to the sheet. However, in the case of a color image on which three or four colors are superposed, if an image is inclined every sheet, color is changed in every sheet due to deviation of dot formation of each color. Further, since it takes time to calculate for inclination of an image, productivity is largely reduced. Thus, the skew feeding of a sheet is determined by performance of conveying precision of a sheet.
Generally, the skew feeding of a sheet and registration are independently controlled, but in recent years, there is proposed a method for correcting the skew feeding and correcting registration in a direction intersecting with the sheet conveying direction at the same time or by the same driving operation (see Japanese Patent Laid-Open No. 10-310289). More specifically, it includes two moving drive motors which independently slide two rollers arranged in the sheet conveying direction in a direction intersecting with the sheet conveying direction, and two optical sensors which detect a side edge (end) of a sheet are arranged in the sheet conveying direction corresponding to the roller. Control is carried out such that the rollers are slid in the width direction so that the side edge of the sheet follows the optical sensor.
According to the conventional method, however, since the rollers are slid in the direction intersecting with the sheet conveying direction to correct the skew feeding of the sheet or correct the position of the sheet in the width direction, stress is applied to the sheet when the rollers slide. Especially, in the case of a thin paper sheet, since a sheet is bent between the two rollers, it is difficult to precisely correct the skew feeding of a sheet or correct a position of a sheet in the width direction.
According to the conventional method, since the moving drive motor is rotated normally and reversely by an ON/OFF operation of the optical sensor, a sheet overshoots in the width direction and reciprocates, and it takes time for a side edge of the sheet to reach a target position. If an attempt is made to enhance the position precision of an image with respect to a sheet, the conveying velocity of the sheet cannot be increased, and the productivity cannot be enhanced.
Hence, the present invention provides an image forming apparatus which can handle various kinds of materials including a sheet having weak elasticity such as a thin paper sheet, and which has excellent position precision of an image with respect to a sheet, and which enhances the productivity.


Pipelines, such as oil, water or sewer distribution or collections systems, are constructed by welding together a plurality of pipes, often at the installation site of the pipeline.
Known in the art are automated orbital pipeline welding systems, such as disclosed in U.S. Pat. No. 4,373,125, issued Feb. 8, 1983 to Kazlauskas. These automated systems are capable of forming accurate and strong welds on large diameter pipes. Such systems are relatively large, typically weighing over 500 kilograms, and are installed at a stationary location, such as an oil rig. Accordingly, such systems are not suitable for mobile field use.
More mobile welding systems are known. Typically, such systems comprise a welding carriage, or "bug" as often termed in the art, which includes a welding torch. The torch may be suited for Gas Metal Arc Welding (GMAW), Shielded Metal Arc Welding (SMAW) or Gas Tungsten Arc Welding (GTAW). The carriage is typically the size of a hand-held power tool and is mounted, via constrained rollers, on an annular rail or guide disposed on the weldment. The carriage includes a driving pinion which meshes with a toothed rack of the annular guide, thereby providing a means for guiding the carriage and torch around the weldment. Typically, the carriage has at least one d.c. brush type motor mounted thereon for driving the carriage on the guide as well as a motor for oscillating the torch. Typically too, the electronic control system for controlling the motors is housed in a separate unit, remote of the carriage, and linked thereto through a plurality of control cables.
There are various types of control systems for these types of bugs. One type of control system, based on analog electronics, employs potentiometers which are adjustable by an operator during the welding process. These potentiometers control the speed of the carriage drive mechanism motor, the torch oscillating motor, and, if present, a consumable electrode wire feed motor. Operators using such a system almost always adjust the speeds of the various motors during the welding process, particularly in order to avoid the problem of having the deposited weld bead, which is liquid, drip due to the influence of gravity. The problem with using such systems, however, is that welders have complete control of the welding process and can adjust the speeds of the motors such that the resulting weld does not always fall within the requisite specifications for the weld. The problem is further compounded by the fact that often the potentiometers are not linear.
Other known bug control systems employ largely digital control systems wherein, in combination with suitable carriages, many of the weld parameters can pre-programmed. For example, one known type of mobile automated welding system allows the weld current, arc voltage, welding speed, oscillation speed, width and dwell time, torch height, tilt angle and annular position, to be digitally programmed. This system also provides a programmed means for controlling the carriage travel speed to deal with the deposited metal drip problems. Similar systems known in the art, such as disclosed in U.S. Pat. No. 5,534,676 issued Jul. 9, 1996 to Rinaldi et. al., have more sophisticated methods for accomplish this objective. However, one limitation common to these types of systems is a lack of flexibility in enabling the welder to vary the pre-programmed parameters during the welding process.
In any event, these mobile welding machines are often used in some of the harshest and most remote environments in the world. Thus, reliability of the machines is important. There are a number of limitations in the present design of mobile welding machines of the types described above that affect their reliability. Welding machines having the known fully automated digital control systems tend to have many sensors and other delicate mechanisms which are prone to breakage in use, particularly under heavy use in harsh construction environments. Welding machines having the analog control systems require frequent recalibration, particularly under operating conditions wherein the ambient temperature fluctuates widely. In addition, irrespective of the type of control system, brush-type motors mounted on the carriage have a tendency to bum out within a relatively short period of time. Moreover, the signals carried by such cables can be prone to electromagnetic interference caused by nearby operating machinery, particularly high frequency inverter type power sources which radiate relatively large amounts of electromagnetic energy.
In addition to having a reliable welding system, it is also important to ensure the quality of the resulting weld, particularly as the weld is being formed. Thus, it is desired to have a real time weld monitoring system. Some of the welding machines of the prior art having automated digital control systems provide a feedback to a remote computer indicating what the actual values of some of the carriage and welding parameters are. However, these systems do not inform the operator in real time whether the weld is being properly made. It would be helpful to have more comprehensive weld quality information readily available so that the operator could immediately adjust certain operating parameters to ensure the quality of the weld.
The present invention seeks to address many of the limitations of the prior art mobile pipeline welding systems described above.


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