<p>One kind of sequential problem is making control decisions in real time. Consider the problem of driving a vehicle. The system will have a state, you can observe some measurements, and you must make a decision. You decision generates and input which then affect the future state of the vehicle and the whole process repeats. A problem which interacts with an external entity that changes its behavior based on a decision is sequential in nature. Other examples include things like optimally managing a stock portfolio, searching for an evading opponent, optimally playing a card game. </p>

<p>One non-sequential problem is classifying the fruit on a scanner in a grocery store. A measurement is taken, the data is processed and and output is determined. When the output generated does not alter the nature of of future outputs, it is non-sequential.</p>

CC BY-SA 3.0
2011-12-28T15:25:13.123Z
2011-12-28T15:25:13.123Z
user1048258
<p>The most obvious example in the field of neural networks:</p>

<ul>
<li>image classification is a non-sequential task</li>
<li>neural machine translation (and most other NLP problems) are sequential tasks, because the translation of a given word in a sentence does not only depend on the word itself, but also on the translation of the previous word (e.g. whether <code>arm</code> was interpreted as limb or as weapon).</li>
</ul>

CC BY-SA 4.0
2019-01-19T18:22:49.327Z
2019-01-19T18:22:49.327Z
dopexxx
<p>I ask this because I'm currently learning about Neural Networks as a subset of the machine learning algorithms</p>

<p>Just trying to get some intuition on what sort of problems out there are categorized as "sequential" while others "non-sequential"</p>

<p>Thanks :)</p>

CC BY-SA 3.0
2011-12-22T12:34:48.833Z
All P-complete problems are believed to be inherently sequential, but proving as much requires separating P from NC.
Tyson Williams
CC BY-SA 3.0
2011-12-30T05:05:51.197Z
The scope of cstheory is theoretical computer science. Please check the sites linked in the [FAQ] for general AI questions. Also please provide definitions or provide links to them so people not familiar with the topic can understand the question, see the links in the [FAQ] for how to write a good question.
Kaveh
<ai.artificial-intel><ne.neural-evol>
What are some examples of sequential-decision tasks?
Chuck Testa
# What are some examples of sequential-decision tasks?

(Asked by: username_0 on 2011-12-22)

I ask this because I'm currently learning about Neural Networks as a subset of the machine learning algorithms

Just trying to get some intuition on what sort of problems out there are categorized as "sequential" while others "non-sequential"

Thanks :)

**Tags:** ai.artificial-intel, ne.neural-evol

> **Comments:**
> **username_1**: All P-complete problems are believed to be inherently sequential, but proving as much requires separating P from NC.  
> **username_2**: The scope of cstheory is theoretical computer science. Please check the sites linked in the [FAQ] for general AI questions. Also please provide definitions or provide links to them so people not familiar with the topic can understand the question, see the links in the [FAQ] for how to write a good question.  

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## 2 answers

### Answer by username_3 on 2011-12-28. Score: 1

One kind of sequential problem is making control decisions in real time. Consider the problem of driving a vehicle. The system will have a state, you can observe some measurements, and you must make a decision. You decision generates and input which then affect the future state of the vehicle and the whole process repeats. A problem which interacts with an external entity that changes its behavior based on a decision is sequential in nature. Other examples include things like optimally managing a stock portfolio, searching for an evading opponent, optimally playing a card game.

One non-sequential problem is classifying the fruit on a scanner in a grocery store. A measurement is taken, the data is processed and and output is determined. When the output generated does not alter the nature of of future outputs, it is non-sequential.


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### Answer by username_4 on 2019-01-19. Score: 0

The most obvious example in the field of neural networks:

* image classification is a non-sequential task
* neural machine translation (and most other NLP problems) are sequential tasks, because the translation of a given word in a sentence does not only depend on the word itself, but also on the translation of the previous word (e.g. whether `arm` was interpreted as limb or as weapon).


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