<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">IJMNTA</journal-id><journal-title-group><journal-title>International Journal of Modern Nonlinear Theory and Application</journal-title></journal-title-group><issn pub-type="epub">2167-9479</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/ijmnta.2017.62006</article-id><article-id pub-id-type="publisher-id">IJMNTA-76860</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Engineering</subject><subject> Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  The Computational Theory of Intelligence: Feedback
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Daniel</surname><given-names>Kovach</given-names></name><xref ref-type="aff" rid="aff1"><sub>1</sub></xref></contrib></contrib-group><aff id="aff1"><label>1</label><addr-line>Quantitative Research, Institute of Trading and Finance, Montreal, Canada</addr-line></aff><author-notes><corresp id="cor1">* E-mail:</corresp></author-notes><pub-date pub-type="epub"><day>14</day><month>06</month><year>2017</year></pub-date><volume>06</volume><issue>02</issue><fpage>70</fpage><lpage>73</lpage><history><date date-type="received"><day>April</day>	<month>26,</month>	<year>2016</year></date><date date-type="rev-recd"><day>Accepted:</day>	<month>June</month>	<year>11,</year>	</date><date date-type="accepted"><day>June</day>	<month>14,</month>	<year>2017</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  In this paper we discuss the applications of feedback to intelligent agents. We show that it adds a momentum component to the learning algorithm. We derive via Lyapunov stability theory the condition necessary in order that the entropy minimization principal of computational intelligence is preserved in the presence of feedback.
 
</p></abstract><kwd-group><kwd>Neural Networks</kwd><kwd> Feedback</kwd><kwd> Intelligence</kwd><kwd> Computation</kwd><kwd> Artificial Intelligence</kwd><kwd> Lyapunov Stability</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>In this paper, we continue the efforts of the Computational Theory of Intelligence (CTI) first introduced in [<xref ref-type="bibr" rid="scirp.76860-ref1">1</xref>] . Here, we investigate the influence of feedback in intelligence processes. It is our intent to show that feedback provides a momentum component to the learning process.</p><p>The fact that feedback is effective in various situations especially those involved with time series data is not novel. Some notable studies include [<xref ref-type="bibr" rid="scirp.76860-ref2">2</xref>] [<xref ref-type="bibr" rid="scirp.76860-ref3">3</xref>] [<xref ref-type="bibr" rid="scirp.76860-ref4">4</xref>] among others. Our intent is to provide a generalized theoretical approach to the addition of feedback into the intelligence process as understood through the framework of CTI.</p><p>We begin with necessary terminology and notation. Recall from [<xref ref-type="bibr" rid="scirp.76860-ref1">1</xref>] that given the two sets <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x2.png" xlink:type="simple"/></inline-formula> and<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x3.png" xlink:type="simple"/></inline-formula>, the intelligence mapping<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x4.png" xlink:type="simple"/></inline-formula>, at a particular time, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x5.png" xlink:type="simple"/></inline-formula>is represented by</p><disp-formula id="scirp.76860-formula217"><label>(1)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x6.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x7.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x8.png" xlink:type="simple"/></inline-formula> This mapping may be updated via the gradient of a learning function <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x9.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.76860-formula218"><label>(2)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x10.png"  xlink:type="simple"/></disp-formula><p>For the remainder of this paper, we will investigate the effects of introducing feedback into the formulation discussed above.</p></sec><sec id="s2"><title>2. Feedback</title><p>For the purposes of this paper and its application to the Computational Theory of Intelligence, we define feedback as a process by which the result of a previous iteration of the intelligence process is combined with the input into a subsequent application. Typically, the epochs differ by one iteration, and we will proceed with this in mind.</p><p>Let us consider Equation (1) and make a slight adjustment by considering the above assumptions, and the output of the previous epoch <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x11.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.76860-formula219"><label>(3)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x12.png"  xlink:type="simple"/></disp-formula><p>Note that, due to the application of the addition operation between respective elements of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x13.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x14.png" xlink:type="simple"/></inline-formula> we are obliged to ensure that this operation is meaningfully defined between elements of these two sets. Also, for notational brevity we have removed the superscripts <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x15.png" xlink:type="simple"/></inline-formula> and<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x16.png" xlink:type="simple"/></inline-formula>. We will proceed in this manner when the context is clear.</p><p>Explicit enumeration of each step in the recursive process gives us the following:</p><disp-formula id="scirp.76860-formula220"><label>(4)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x17.png"  xlink:type="simple"/></disp-formula><p>At this point we cannot move forward until we pontificate as to the nature of the<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x18.png" xlink:type="simple"/></inline-formula>. At the beginning of this section, our intent was to simply incorporate knowledge from previous iterations into the intelligence process. It therefore stands to reason that each subsequent input is related to the next in some way, as if perhaps by some function<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x19.png" xlink:type="simple"/></inline-formula>. In particular, if <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x19.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x20.png" xlink:type="simple"/></inline-formula> depends on some initial value<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x19.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x20.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x21.png" xlink:type="simple"/></inline-formula>, we have</p><disp-formula id="scirp.76860-formula221"><label>(5)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x22.png"  xlink:type="simple"/></disp-formula><p>This insight will prove extremely valuable in determining in what types of applications feedback will be most efficacious.</p><p>Implementing Equation (5), Equation (4) becomes</p><disp-formula id="scirp.76860-formula222"><label>(6)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x23.png"  xlink:type="simple"/></disp-formula><sec id="s2_1"><title>2.1. Momentum</title><p>If we carry the ideas of this section further, we can apply our discussion about feedback to derive momentum terms to the learning function. If we expand the definition of the learning function taking into account the developments from Equation (6), we have</p><disp-formula id="scirp.76860-formula223"><label>(7)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x24.png"  xlink:type="simple"/></disp-formula><p>Applying the gradient operator as per Equation (2), we have</p><disp-formula id="scirp.76860-formula224"><label>(8)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x25.png"  xlink:type="simple"/></disp-formula><p>We may expand the above expression through diligent application of the chain rule:</p><disp-formula id="scirp.76860-formula225"><label>(9)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x26.png"  xlink:type="simple"/></disp-formula><p>Distributing terms and rearranging,</p><disp-formula id="scirp.76860-formula226"><label>(10)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x27.png"  xlink:type="simple"/></disp-formula><p>The above may be thought of as a summation of momentum terms, from the most recent iteration all the way back to the initial epoch.</p><p>Equation (10) may be written more compactly as</p><disp-formula id="scirp.76860-formula227"><label>(11)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x28.png"  xlink:type="simple"/></disp-formula><p>The momentum terms in Equations (10) and (11) are worth mention. As time increases, the amount of products in each momentum term increases. This insures automatically that more recent momentum terms will dominate over those more distal in time (since we are assuming each term is less than or equal to unity). Weighting more recent iterations is a natural consequence of our formulation.</p></sec><sec id="s2_2"><title>2.2. Computational Self-Awareness</title><p>Finally, it might be insightful to quantify the ratio of the two sources, new information and that which came from feedback, at some particular epoch<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x29.png" xlink:type="simple"/></inline-formula>. If we denote this quantity<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x29.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x30.png" xlink:type="simple"/></inline-formula>, then</p><disp-formula id="scirp.76860-formula228"><label>(12)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x31.png"  xlink:type="simple"/></disp-formula><p>For reasons we will discuss later, we will refer to the quantity <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x32.png" xlink:type="simple"/></inline-formula> as the computational self-awareness of the agent facilitating the intelligence process at epoch<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x32.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x33.png" xlink:type="simple"/></inline-formula>. Note that as the input signal tends to zero, so tends the computational self-awareness to infinity.</p></sec></sec><sec id="s3"><title>3. Stability</title><p>One of the core tenets of CTI [<xref ref-type="bibr" rid="scirp.76860-ref1">1</xref>] is that <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x34.png" xlink:type="simple"/></inline-formula> must minimize information entropy locally. We must show that this is still the case even in the presence of feedback. It is well established [<xref ref-type="bibr" rid="scirp.76860-ref5">5</xref>] that recursive feedback in algorithms leads to instability, chaos, and other nonlinear effects. We will apply the study of such systems to this application using Lyapunov stability theory. In particular, we highlight the fact that the entropy of a system increases with the value of the Lyapunov exponent <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x34.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x35.png" xlink:type="simple"/></inline-formula> [<xref ref-type="bibr" rid="scirp.76860-ref6">6</xref>] . By [<xref ref-type="bibr" rid="scirp.76860-ref7">7</xref>] , the Lyapunov exponent may be expressed as</p><disp-formula id="scirp.76860-formula229"><label>(13)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x36.png"  xlink:type="simple"/></disp-formula><p>In a similar manner to our derivation in Section (2.1), we can show that this works out to be</p><disp-formula id="scirp.76860-formula230"><label>(14)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/3-2340216x37.png"  xlink:type="simple"/></disp-formula><p>by our definition of<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x38.png" xlink:type="simple"/></inline-formula>. Since <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x38.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x39.png" xlink:type="simple"/></inline-formula> is a function parameterized by<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x38.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x39.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x40.png" xlink:type="simple"/></inline-formula>, we cannot proceed further in the general case. Thus, the condition for entropy minimization at <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x38.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x39.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x40.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x41.png" xlink:type="simple"/></inline-formula> to hold is that<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x38.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x39.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x40.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x41.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/3-2340216x42.png" xlink:type="simple"/></inline-formula>.</p></sec><sec id="s4"><title>4. Conclusions</title><p>In this paper, we provided a generalized theoretical framework concerning the effect of feedback in the intelligence process. From our derivation, we were able to conclude that feedback adds a “momentum” component to the learning pro- cess, which is of particular interest for time series type data.</p><p>We also discussed computational self-awareness, purely in the context of the ratio of feedback to input. The concept of self-awareness is highly contentious and philosophical and we wish to keep this paper technical. For our purposes, this is simply the extent to which the agent applies feedback in the intelligence process relative to input data.</p></sec><sec id="s5"><title>Cite this paper</title><p>Kovach, D. (2017) The Computational Theory of Intelligence: Feedback. 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