An Analysis on the Fundamental Concept of Knowledge Representation: a Case Study of Ai

Exploring Semantic Entailment and Knowledge Representation in AI

by Ms. Rubina Khan*,

- Published in International Journal of Information Technology and Management, E-ISSN: 2249-4510

Volume 5, Issue No. 1, Aug 2013, Pages 0 - 0 (0)

Published by: Ignited Minds Journals


ABSTRACT

Semantic entailment isthe issue of deciding on the off chance that the significance of a givensentence entails that of an alternate. Inquiry noting might be decreased tothis issue by rethinking the inquiry as an explanation that is entailed byright replies. In [braz et al.,] we show a principled methodology to semanticentailment that expands on actuating re-representations of text snippets into ahierarchical knowledge representation alongside an optimization-basedinferential mechanism that makes utilization of it to demonstrate semanticentailment. Contrasted with pastlogic-based methodologies to sanction, DL gives a novel combo ofcharacteristics: it is based on logic projects, communicates appointmentprofundity unequivocally, what's more backings a wide mixture of complexprincipals. Looked at to past methodologies to trust administration, DL gives analternate novel characteristic: an idea of verification of-agreeability that isnot by any means impromptu and that is based on model theoretic semantics (inthe same way that common logic projects have a model-theoretic semantics). DL'smethodology is additionally novel in that it joins the above characteristicswith smooth extensibility to non-monotonicity, refutation, and prioritizedclash handling. This extensibility isexpert by expanding on the well-comprehended establishment of DL'slogic-program knowledge representation.

KEYWORD

semantic entailment, knowledge representation, AI, logic-based methodologies, DL

INTRODUCTION

Semantic entailment is the undertaking of deciding, for instance, that the sentence: "Walmart shielded itself in court today against claims that its female representatives were kept out of occupations in administration in light of the fact that they are ladies" entails that "Wal- Shop was sued for sexual segregation". Figuring out if the importance of a given text piece entails that of an alternate or whether they have the same importance is a principal issue in regular dialect understanding that requires the capability to digest over the inherent syntactic also semantic variability in common dialect [dagan and Glickman, 2004]. This test is at the heart of a lot of people high level characteristic dialect preparing errands including Question Replying, Information Retrieval and Extraction, Machine Interpretation, and others that endeavor to reason about and catch the significance of linguistic articulations. A knowledge representation (KR) is a thought to empower a single person to determine results by intuition instead of acting, i.e., by reasoning about the world as opposed to making a move in it. There are two essential parts of knowledge representation i.e. reasoning and inference. Indeed KR is the major issue in AI that endeavors to comprehend sagacity. This paper contends that there is an elective methodology to knowledge representation that has the potential of giving focused purpose for an expansive class of provisions. Basically, this methodology, which we term corpus based representation, is based on gathering an extensive corpus of divergent sections of knowledge, and building a set of tools that are based on dissecting properties of the corpus. The pieces of knowledge in the corpus can incorporate single person Kbs, database compositions with or without information cases of the composition, questions composed over Kbs and databases, and any type of meta-information connected with them. Not at all like a KB that needs watchful ontological outline, the corpus is a situated autonomous awkward commitments. The instinct is that if the corpus is extensive enough, then the examples we distinguish in it can be of incredible utilization for knowledge escalated errands.

EXPERIMENTAL EVALUATION AND DISCUSSION

We tried our methodology on a gathering of inquiry reply pairs create by Xerox PARC for a pilot assessment of Knowledge-Oriented Approaches to Question Answering under the ARDA-AQUAINT program. The PARC corpus comprises of 76 Question-Answer pairs explained as "correct", "false" on the other hand "obscure" (and a sign of the kind of reasoning needed to conclude the mark). The inquiry/response pairs gave by PARC are intended to test distinctive instances of linguistic entailment. The

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foundation world knowledge. The center is on inferences that might be made absolutely on the support of the importance of words and phrases. The inquiries are straightforward and consequently effectively changed (by hand) into proclamation structure. One sentence pair including qualifiers was reordered to test qualifier subsumption.

KNOWLEDGE REPRESENTATION

Maybe the most principal inquiry about the idea of knowledge representation is, What is it? We accept that the reply is best seen as far as the five central parts that it plays. A Knowledge Representation Is a Surrogate - Any canny substance that needs to reason about its reality experiences an imperative, unpreventable actuality: Reasoning is a process that goes on inside, yet most things it needs to reason about exist just remotely. A system (alternately individual) occupied with arranging the gathering of a bike, for instance, may need to reason about elements, for example, wheels, chains, sprockets, and handle bars, yet such things exist just in the outside world. This unavoidable dichotomy is a basic basis and part for a representation: It works as a surrogate inside the reasoner, a stand-in for the things that exist on the planet. Operations on and with representations substitute for operations on the genuine article, that is, substitute for immediate connection with the world. In this perspective, reasoning itself is, partially, a surrogate for activity in the world when we can't or don't( (yet) need to make that move. A Knowledge Representation Is a Set of Ontological Commitments On the off chance that, as we contend, all representations are flawed close estimations to actuality, every rough guess going to a few things and overlooking others, then in selecting any representation we are in the exact same act unavoidably settling on a set of choices about how and what to see on the planet. That is, selecting a representation methods making a set of ontological responsibilities. The duties are, in actuality, a solid pair of glasses that figure out what we can see, bringing some a piece of the world into sharp center at the out of pocket of smudging different parts. Similitude networks - In Bayesian multinets, we obliged that each variable be incorporated in every nearby network. This necessity remains as opposed to the perception that in numerous domains every estimation regularly serves to segregate just a particular class of hypotheses. Side effects are frequently identified with tight classes of diseases, and frameworks' shortcomings regularly confine a particular class of potential breakdowns. Evaluating the reliance between two variables under development of a master framework for surgical pathology diagnosis. At the point when the master pathologist was asked by the model manufacturer: Given a specific disease, does watching indication x change your conviction that you will watch side effect y? The pathologist might now and then rep1y : I've never contemplated these two indications in the meantime some time recently. Indication x is applicable to one and only set of diseases, while side effect y is just significant to an alternate set of diseases. These sets of diseases don't cover, and I never confound the first set of diseases with the second. An incorrect answer for this trouble is to incorporate in every nearby network of a Bayesian multinet just those variables that assistance to separate around the hypotheses secured by that nearby network. In doing thus, in any case, significant information for right distinguishing proof may be lost. Case in point in the secured-building issue sex (g) and identification worn don't help to segregate specialists from executives. On the off chance that these variables might not have been delineated in the neighborhood network for {worker,executive} in the Bayesian multinet at that point this multinet might have failed to speak to the bona fide relationship between marker worn and sexual orientation.

CORPUS-BASED KNOWLEDGE REPRESENTATION MATCHING

Possibly, detailed knowledge about the domain in which the matching is constantly performed might be a significant asset in a diagram matching framework. In any case, making a proper KB is regularly hard, and moreover, the consequence may be brittle in the sense it just aides on its domain of scope, furthermore just gives a solitary point of view on the domain. We are seeking after an exchange approach in which knowledge is gleaned by investigating a huge corpus of database blueprints furthermore at one time accepted mappings. There are two sorts of knowledge that we can gather from such a corpus. Initially, we can take in the diverse courses in which words (or terms) are utilized as a part of database structures (i.e., as connection names, characteristic names and information values). Second, the approved mappings indicate how varieties in term uses relate to one another in different structures. In spite of the fact that such a corpus is not simple to build, it is an extremely distinctive sort of action than building a detailed and complete knowledge base. It doesn't require the cautious ontological plan as a knowledge base does, nor the watchful control on its substance, accordingly uprooting the key bottlenecks exhibit in the configuration of knowledge bases. The

Ms. Rubina Khan

knowledge that is suitable to matching two divergent patterns. In our introductory take a shot at the LSD framework [doan et al., 2001], we researched the profit of gaining from beforehand approved mappings. In [doan et al., 2001] we recognized the situation where different information sources are mapped to a solitary interceded outline, on which clients posture questions. We gave LSD with the interceded pattern and a set of training matches for some information sources. LSD utilized these matches to take in models of the components of the intervened diagram. Since no single taking in algorithm catches all the prompts from the domain, we utilized a multi-method approach that joined together the forecasts of a few learners. We then asked LSD to anticipate matches between the intervened diagram and a set of test patterns. Our tests indicated that (1) it is conceivable to accomplish high correctness with multi-method taking in, and (2) extra exactness is obtained by acknowledging domain constraints (i.e., a basic type of domain knowledge). Generally, LSD accomplished matching precision of 75-90% on little to medium measured patterns of information sources on the Web. We stretched out LSD to think about straightforward scientific classifications of ideas in [doan et al., 2002]. In late work [madhavan et al., 2003], we examine the profit of a corpus of patterns and matches, and the capacity to utilize such a corpus to foresee mappings between a pair of patterns that have not been at one time seen. Like in LSD, we take in models for components in the corpus, utilizing both the information available in the pattern and accepted matches that are gave in the corpus. Given two patterns, S1 and S2, we ascertain for every component in them a similitude vector w.r.t. the corpus, i.e., how comparative every component in Si is to every component in the corpus. Harshly talking, if the likeness vectors of two components a1  S1 and a2  S2 are like one another, then we anticipate that a1 matches a2. The outcomes of our analyses demonstrate that (1) even with a humble corpus of 10 outlines we can attain great precision, and (2) the right matches found by utilizing the corpus and those found by other a while ago known strategies cover, yet have noteworthy contrasts. Thus, the utilization of the corpus is finding matches that might not have been anticipated by different procedures.

KNOWLEDGE REPRESENTATION USING SEMANTIC NET

A semantic network is generally utilized knowledge representation procedure. As the name semantic class of items and edges or link (unidirectional) is utilized to speak to the semantic relations between the articles. Semantic network are by and large used to speak to the inheritable knowledge. Inheritance is most suitable type of inference. Inheritance is the property in which component of a few class inherit the quality and qualities from some different class as indicated to help inheritance object must be sorted out into classes and classes must be orchestrated in a generalization pecking order. At times Semantic nets are additionally called as acquainted nets since hubs are co-partnered or identified with others hub as there is an enactment spreading structure one idea hub to different hubs This sorts of connections have demonstrated especially helpful in a wide assortment of knowledge representations. Ordinarily utilized links within semantic nets are i.e. IS-An, and A-KIND-OF. IS-A methods is an occurrence of or alludes to a part of a few class inasmuch as A-KIND-OF speaks to the link from one class to different class as appeared Semantic networks are a revelatory realistic representation that might be utilized either to speak to knowledge or to backing mechanized frameworks for reasoning about knowledge. Taking after are six of the most well-known sorts of semantic networks. 1. Definitional networks 2. Assertional networks 3. Implicational networks 4. Executable networks 5. Taking in networks 6. Mixture networks

KNOWLEDGE BASE PROCESS MODEL/STRUCTURE

The KR framework must have the capacity to speak to any sort of knowledge, "Syntactic, Semantic, logical, Presupposition, Understanding poorly shaped info, Ellipsis, Case Constraints, Vagueness". For making it more viable the knowledge representation model is isolated into five separate parts the K Box, Knowledge Base, Query applier, reasoning and client interface as demonstrated in figure. K Box :- The first some piece of K Box takes The data from the outside world through client interface. The wellspring of information could be a book, novel, Newspaper and so forth. The Input from the client is separated into two classifications either it could be

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methodology to check whether that knowledge is as of now in knowledge base if yes then framework will dispose of that. Else it checks whether that knowledge will be suit by the existing framework if yes then division process has been carried out on the information to weigh in which classifications it lies and divides the movement with the other. Characteristic Extraction a piece of K Box is utilized to check whether there is an action might be perform or a few methodology is to be available in the approaching text for Ex. Versatile is ringing then the methodology is going ahead in this approaching knowledge implies some sound is advancing and the root of ringing is ring. On the off chance that the sentence is similar to slam is a kid then no activity will be performed. On the off chance that the approaching knowledge is straightforward sentence then we can speak to it by utilizing semantic net, casings and predicate logic however when some movement could be performed by the substance then we require a structure that could be dynamic in nature and must be expressive. Inquiry Applier is utilized for getting the truths from the framework and afterward passes the information to the inference mechanism for reasoning. At whatever point the new inquiry comes framework will take in whether that question is identified with the past question or it produces from the past inquiry and check what number of time client request the mixture from these. Reasoning is utilized for getting new certainty from the existing knowledge. The least complex reasoning system is forward and retrogressive reasoning.

Figure: Knowledge Base System Model/Architecture

CONCLUSIONS

This paper shows a principled, incorporated methodology to semantic entailment. We created an bag of machine taking in based tools. An inferential mechanism over a knowledge representation that helps both reflections and a few levels of representations permits us to start to address paramount issues in abstracting over the variability in characteristic dialect. Our preparatory assessment is exceptionally empowering, yet leaves a great deal to trust for. Enhancing our assets and creating approaches to increase the KB is a portion of the paramount steps we have to take. Past that, we mean to tune the inference algorithm by joining a superior mechanism for picking the fitting level at which to oblige subsumption. Given the way that we improve a direct capacity, it is straightforward to take in the expense capacity. Additionally, this could be carried out in such a path, to the point that the choice rundown structure is maintained. Corpus-based representation offers numerous energizing exploration challenges, not the slightest of which is really gathering a huge enough corpus to be of investment. Also, there is an inquiry about how centered the corpus needs to be so as to be handy in a specific domain. That is, would it be able to just have domain demonstrates in that domain? Can domains demonstrates in other (perhaps related) domains be advantageous, or do they just present commotion that corrupts the execution? At long last, regardless of how a corpus is built, it can most likely be physically tuned to perform surprisingly better. What structure does such tuning take? While the tests for corpus-based representation are huge, we accept the adjustments could be immense, and the effects can profoundly affect how we make and use organized knowledge. In AI for particular domain there is a knowledge base underpinned by different strategies for speaking to the knowledge. There are different knowledge representation plots in AI. All have distinctive semantics, structure and distinctive level of force. This paper has introduced the correlation between three representation plans appeared annexure 1 and the destination is to investigates the force and expressiveness of a framework. Every knowledge representation plan has points of interest and weaknesses. Combo of two or more representation plan may be utilized to for making the framework more productive and enhancing the knowledge representation.

REFERENCE

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Ms. Rubina Khan

Pennsylvenia, Philadelphia, 1999.  Doyle. J., and Patil, R. 1989. Two Dogmas of Knowledge Representation, Technical Memo, 387B, Laboratory for Computer Science, Massachusetts Institute of Technology.  Frank van Harmelen, “Knowledge Representation and Reasoning “Vrije Universitetit Amsterdam, http://www.cs.vu.nl/en/sec/ai/kr.  G.F. Cooper and E. Herskovits, A Bayesian method for the induction of probabilistic networks from data, Mach. Learn. 9 ( 1992) 309-347.  Hayes, P. 1978. Naive Physics I: Ontology for Liquids.  In Formal Theories of the Commonsense World, eds. J. R. Hobbs and R. C. Moore. Norwood, N.J.: Ablex.  J.W. Lloyd, Foundations of Logic Programming, second edition, Springer, Berlin, 1987.  M. Longhair (editor), “A P3P Preference Exchange Language (APPEL) Working Draft,” W3C Working Draft 9, October 1998, http://www.w3.org/P3P/Group/Preferences/Drafts/WD-P3P-preferences-19981009.  Nilsson, N. 1991. Logic and Artificial Intelligence. Artificial Intelligence 47(1): 31–56.  Noy and Musen, 2002 Natalya Noy and Mark A. Musen. PROMPTDIFF: A fixed-point algorithm for comparing ontology versions. In Proceedings of AAAI, 2002.  P. Resnick and J. Miller, “PICS: Internet access controls without censorship,” Communications of the ACM, 39 (1996), pp. 87–93.  Polyzotis and Garofalkis, 2002 Neoklis Polyzotis and Minos N. Garofalkis. Statistical synopses for graphstructured XML databases. In SIGMOD ’02, 2002.  R. Cox, Probability, frequency and reasonable expectation, Am. J. Phys. 14 (1946) I- 13.  R. Reiter, “A Logic for Default Reasoning,” Artificial Intelligence, 13 (1980), pp. 81–132.  S.T. Kent, “Internet Privacy Enhanced Mail,” Communications of the ACM, 8 (1993), pp. 48–60.

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