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Dissertations / Theses on the topic 'Word retrieval'
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Flack, Cassie. "Word retrieval treatment using collaborative referencing /." View online, 2008. http://repository.eiu.edu/theses/docs/32211131414670.pdf.
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Sanderson, Mark. "Word sense disambiguation and information retrieval." Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/4463/.
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Starting with a review of previous research that attempted to improve the representation of documents in IR systems, this research is reassessed in the light of word sense ambiguity. It will be shown that a number of the attempts' successes or failures were due to the noticing or ignoring of ambiguity. In the review of disambiguation research, many varied techniques for performing automatic disambiguities are introduced. Research on the disambiguating abilities of people is presented also. It has been found that people are inconsistent when asked to disambiguate words and this causes problems when testing the output of an automatic disambiguator. The first of two sets of experiments to investigate the relationship between ambiguity, disambiguation, and IR, involves a technique where ambiguity and disambiguation can be simulated in a document collection. The results of these experiments lead to the conclusions that query size plays an important role in the relationship between ambiguity and IR. Retrievals based on very small queries suffer particularly from ambiguity and benefit most from disambiguation. Other queries, however, contain a sufficient number of words to provide a form of context that implicitly resolves the query word's ambiguities. In general, ambiguity is found to be not as great a problem to IR systems as might have been thought and the errors made by a disambiguator can be more of a problem than the ambiguity it is trying to resolve. In the complementary second set of experiments, a disambiguator is built and tested, it is applied to a document test collection, and an IR system is adjusted to accommodate the sense information in the collection. The conclusions of these experiments are found to broadly confirm those of the previous set.
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Uzuner, Ozlem 1975. "Word sense disambiguation applied to information retrieval." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9874.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (leaves 45-46).
by Ozlem Uzuner.
S.B.and M.Eng.
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Chan, On-kei Angel. "Word and compound retrieval in Cantonese aphasic speakers." Click to view the E-thesis via HKUTO, 1998. http://sunzi.lib.hku.hk/hkuto/record/B36209624.
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Thesis (B.Sc)--University of Hong Kong, 1998."A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, April 30, 1998." Also available in print.
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Stokoe, Christopher. "Automated word sense disambiguation for Web information retrieval." Thesis, University of Sunderland, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408881.
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Vechtomova, Olga. "Approaches to using word collocation in information retrieval." Thesis, City University London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390942.
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Lyalka, Oksana. "Mechanisms underpinning semantic priming in spoken word retrieval." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3716.
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A number of studies have shown that speed and accuracy of word retrieval may be affected by the previous retrieval of a word with similar semantic meaning. This phenomenon is called semantic priming and includes both semantic interference or and facilitation. While there is a clear evidence for the presence of semantic priming, the mechanisms causing this effect are still under debate. Therefore, the goal of this PhD was to provide evidence regarding these mechanisms by systematically evaluating the effect of primes with different semantic relations on the speed and accuracy of spoken word retrieval in healthy subjects and people with aphasia. Five experiments were implemented with healthy participants focusing on the effects in priming of semantic coordination, association and part-whole relations on spoken word retrieval with zero or four intervening items between prime and target (lags 0 and 4). Chapter Two reports two experiments using an alternating word reading and picture naming paradigm and Chapter Three, three experiments using a continuous picture naming paradigm. Chapter Four reports two experiments with people with aphasia examining the effects of identity, semantic coordination, association and their interaction on facilitation of picture naming. The results of these two experiments were analysed at both individual subject and group levels. In Chapter Five, these experiments are placed in the context of the previous literature on semantic priming and theories of semantic representation. In this regard, the experimental results are taken to imply that semantic coordination, association, and part-whole relations can be attributed to different types of semantic relations that have different representation and organisation. Further implications of the experiments for our understanding of the mechanisms of lexical access and the nature of lexical representation are discussed.
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Zak, Marsha Gale. "Word retrieval deficits in adults with brain tumors." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288872.
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The relationship between brain invaded by tumor and consequent word retrieval deficits was investigated. Performance scores from 10 individuals who underwent craniotomy for tumor resection were obtained using contexts of constrained naming, verbal fluency, and picture description during pre- and post-craniotomy. This study described qualitative and quantitative differences of impairment to elucidate the nature and extent of naming impairment in individuals with cerebral hemisphere tumors. For all tasks, independent of group, performance decrements were reported pre-operatively in relation to normative data, with subsequent post-operative decline. This was particularly true for the Left Hemisphere Group who exhibited poorer performance than the Right Hemisphere Group. It was expected that the Frontal Group would have greater difficulty on tasks requiring intact frontal lobe function (i.e. Verbal Fluency), but the Non-Frontal Group performed more poorly. Surprisingly, the Frontal Lobe Group showed the smallest decrement, and the Non-Frontal and Left Hemisphere Groups showed the worst performance overall. Pre- and post-operatively, all subjects exhibited greater word retrieval deficits than normal controls during verbal fluency tasks. The overall disruption of word retrieval across tasks was predictable for time of examination, but not for site of lesion. The results of this study suggest that the word retrieval deficits of brain tumor patients may differ from traditional aphasia profiles. This knowledge may contribute to a better understanding of language processing and production in tumor-related aphasia.
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Whitworth, Anne B. "Thematic role assignment in word retrieval deficits in aphasia." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238814.
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Christofaris, Lynne D. "Semantic and Phonological Relationships to Word Retrieval during Aging." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1209768680.
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Harvey, Clare Frances. "The development of a computerised word-of-mouth emulator." Thesis, University of Sunderland, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240492.
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Wigder, Chaya. "Word embeddings for monolingual and cross-language domain-specific information retrieval." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233028.
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Various studies have shown the usefulness of word embedding models for a wide variety of natural language processing tasks. This thesis examines how word embeddings can be incorporated into domain-specific search engines for both monolingual and cross-language search. This is done by testing various embedding model hyperparameters, as well as methods for weighting the relative importance of words to a document or query. In addition, methods for generating domain-specific bilingual embeddings are examined and tested. The system was compared to a baseline that used cosine similarity without word embeddings, and for both the monolingual and bilingual search engines the use of monolingual embedding models improved performance above the baseline. However, bilingual embeddings, especially for domain-specific terms, tended to be of too poor quality to be used directly in the search engines.Flera studier har visat att ordinbäddningsmodeller är användningsbara för många olika språkteknologiuppgifter. Denna avhandling undersöker hur ordinbäddningsmodeller kan användas i sökmotorer för både enspråkig och tvärspråklig domänspecifik sökning. Experiment gjordes för att optimera hyperparametrarna till ordinbäddningsmodellerna och för att hitta det bästa sättet att vikta ord efter hur viktiga de är i dokumentet eller sökfrågan. Dessutom undersöktes metoder för att skapa domänspecifika tvåspråkiga inbäddningar. Systemet jämfördes med en baslinje utan inbäddningar baserad på cosinuslikhet, och för både enspråkiga och tvärspråkliga sökningar var systemet som använde enspråkiga inbäddningar bättre än baslinjen. Däremot var de tvåspråkiga inbäddningarna, särskilt för domänspecifika ord, av låg kvalitet och gav för dåliga resultat för direkt användning inom sökmotorer.
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Johnson, Angela Lynne. "Physiological Arousal, Emotion, and Word Retrieval in Aphasia: Effects and Relationships." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9108.
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People with aphasia are known to have poor word retrieval abilities in communicative tasks. It has also been reported that they have lower, non-optimal levels of physiological arousal, which may cause lower attention levels therefore contributing to poor performance on linguistic tasks. The purpose of this study was to investigate the relationship between physiological arousal and word retrieval in adults with aphasia and neurotypical adults when presented with emotional stimuli within a confrontational naming task. Participants included 6 people with aphasia and 15 neurotypical controls. All participants completed a confrontational naming task within 3 emotional conditions (neutral, positive, negative) and physiological measures (Heart Rate Variability, Skin Conductance) were taken simultaneously. No statistically significant results were found; however, numerical trends were identified in the data that may provide direction when designing future studies.
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Pera, Maria Soledad. "Improving Library Searches Using Word-Correlation Factors and Folksonomies." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1972.
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Libraries, private and public, offer valuable resources to library patrons; however, formulating library queries to retrieve relevant results can be difficult. This occurs because when using a library catalog for library searches, patrons often do not know the exact keywords to be included in a query that match the rigid subject terms (chosen by the Library of Congress) or terms in other fields of a desired library catalog record. These improperly formulated queries often translate into a high percentage of failed searches that retrieve irrelevant results or no results at all. This explains why frustrated library patrons nowadays rely on Web search engines to perform their searches first, and upon obtaining the initial information, such as titles, subject areas, or authors, they query the library catalog. This searching strategy is an evidence of failure of today's library systems. In solving this problem, we propose an enhanced library system, called EnLibS, which allows partial, similarity matching of (i) tags defined by ordinary users at a folksonomy site which describe the content of books and (ii) keywords in a library query to improve the searches on library catalogs. The proposed library system allows patrons to post a query Q with commonly-used words and ranks the retrieved results according to their degrees of resemblance with Q. Experimental results show that EnLibS (i) reduces the amount of queries that retrieve no results, (ii) obtains high precision in retrieving and accuracy in ranking relevant results, and (iii) achieves a processing time comparable to existing library catalog search engines.
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Burney, Tiniyja. "Analyzing the Correlation Between Attention and Word Retrieval in Persons with Aphasia." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586538828229999.
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Crawford, Maria Anne, and n/a. "Speed of retrieval after traumatic brain injury." University of Otago. Department of Psychology, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060830.115029.
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Although it is well established that persons with traumatic brain injury (TBI) experience word retrieval difficulties, the underlying cause of these deficits is not known. Difficulties with word retrieval have negative social implications as they can impact on the ability to converse with others. The overarching goal of this dissertation was to determine the underlying cause of problems with word retrieval after TBI.
To test word retrieval in this dissertation, participants were given a series of word fluency tasks and the speed of word generation was measured. In addition to measuring interresponse times, procedures used by Rohrer, Wixted, Salmon and Butters (1995) were also followed. This involved the calculation of parameter estimates to investigate whether slowed retrieval or degraded semantic stores were responsible for the patients� word retrieval difficulties. One parameter (N) was a measure of the total number of retrievable words and the second parameter (tau) was an estimate of mean latency.
Study 1 was designed to trial the procedure and equipment adopted throughout this dissertation to analyse speech. University students were presented with categories on a computer screen and asked to generate as many exemplars as possible in 60 seconds. A PowerLab Chart sound system was used to measure the time that each word was generated. The results of Study 1 showed that the methodology of previous research could be replicated using the PowerLab Chart sound system.
In Study 2, persons with postconcussion syndrome (PCS) and matched controls were given two word fluency tasks. Results showed that on both tasks patients recalled fewer words, had longer pauses between words, and took significantly longer to generate their first word than controls. Also, patients had a significantly reduced N relative to controls, but there was no difference in tau between patients and controls. Given that the participants had not finished responding and that parameter estimates require responses to be exhausted, Study 3 was designed to replicate the findings of Study 2 using an extended recall period.
In Study 3, patients with PCS and matched controls completed a series of word fluency tasks and were given extended periods of time to generate words. Results showed that the patients obtained significantly fewer words on two of the tasks, but no evidence of slowed retrieval was found. There was also no difference in the estimates of N and tau between patients and controls. As the patients in Study 3 sustained more minor injuries than those in Study 2, Study 4 tested patients with severe TBI.
In Study 4, patients with severe TBI and matched controls were given a series of word fluency tasks. Results showed that the patients generated fewer words and experienced slowed retrieval. Again, there was no difference in the estimates of N and tau between patients and controls. The results of Study 4 confirmed the hypothesis that slowed word retrieval is a consequence of TBI. Taken together, the results of this dissertation show that an underlying slowness of processing is the primary cause of problems with word retrieval in persons with TBI.
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Burrill, Katheryn Elizabeth. "The effect of phonological and semantic cues on word retrieval in adults." Scholarly Commons, 2008. https://scholarlycommons.pacific.edu/uop_etds/694.
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Word retrieval difficulties can affect individuals who have had strokes or head trauma (Goodglass & Wingfield, 1997) and to a lesser extent, typically aging adults. This can affect an individual's ability to name pictures accurately and quickly. Cues are used to help individuals with word retrieval difficulties in fmding specific words. Two commonly used cues are semantic and phonological cues. Semantic cues can be information about the word the person is trying to retrieve, such as its definition, and/or its functions. Phonological cues are usually the initial sound of a word that a person is attempting to retrieve. Previous research has suggested that both of these cues, in isolation, are effective in stimulating word retrieval during naming tasks (Li & Williams 1989; Stirnley & Noll 1991 ). However, research has not investigated the effects of combining these two cues during picture naming tasks. The current study observed participants under four different cueing conditions during a picture naming task with the Boston Naming Test.
The four conditions include a control group (received no cues), a semantically cued group (received a semantic cue before being asked to name a picture), a phonologically cued group (received a phonological cue before being asked to name a picture), and a semanticallyphonologically cued group (received a semantic and phonological cue before being asked to name a picture). Each group was compared on number of items correctly named and response times. The results indicated that there was no statistically significant difference between the groups with regard to number of items named. There was a statistically significant difference found between the groups with regards to response times. These findings are discussed and compared to previous research and current word retrieval theories.
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Pillay, Bhavani S. "Semantic feature analysis for word retrieval in a small aphasia-group setting." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/58976.
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Background: Word retrieval deficits are a common, pervasive feature of aphasia. Semantic feature analysis (SFA) is a popular treatment technique for word retrieval impairment. Preliminary evidence of its use in small aphasia-group settings suggests improved word retrieval in discourse-based tasks with improvements in communicative informativeness (Antonucci, 2009; Falconer & Antonucci, 2012).
Objective: The aim of this study was to investigate the training of SFA within discourse during a small (two-member) aphasia group treatment to ascertain if gains would be made in word retrieval abilities and communicative informativeness.
Method: Two female participants with chronic aphasia, aged seventy seven and sixty eight, participated weekly in group treatment for five consecutive weeks where stimuli were used to elicit increasingly naturalistic discourse. A multiple-baseline design was used and a case series analysis conducted. Baseline measures, treatment data and data from the six week follow-up (SWFU) session were analysed using the protocols developed by Nicholas and Brookshire (1993) and Mayer and Murray (2003).
Results: Both participants demonstrated certain modest gains in overall communicative informativeness but these were not maintained at the SWFU session. Gains in informativeness ranged from 12% to 13.4% for participants, which agree with improvements in other studies (Antonucci, 2009; Boyle & Coelho, 1995; Falconer & Antonucci, 2012). P2 (presented with anomic aphasia) performed better than P1 (presented with Broca’s aphasia and a component of apraxia of speech [AOS]) with regards to communicative informativeness (%CIUs) and had greater access to semantic knowledge (i.e. could access lexical forms at an improved rate).
Conclusion: The small group setting may offer advantages to facilitate communication skills and increase participation in everyday conversation. Further research is needed to identify benefits for individuals with differing aphasia types and severity, optimal intensity and frequency of group treatment and the role of peer support during group interaction.
Key Words
Aphasia, stroke rehabilitation, word retrieval, semantic feature analysis, connected speech, discourse, group therapy, communicative informativeness, functional communication.Dissertation (MA)--University of Pretoria, 2016.
Speech-Language Pathology and Audiology
MA
Unrestricted
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Blake, Priscilla Jane. "Word retrieval behaviors of aphasic adults in conversational speech : a preliminary study." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4213.
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Word retrieval difficulties are experienced by almost all aphasic adults. Consequently, these problems receive a substantial amount of attention in aphasia treatment. Because of the methodological difficulties, few studies have examined WRBs in conversational speech, focusing instead on confrontational naming tasks in which the client is asked to retrieve a specific word. These studies have left unanswered questions about the WRB processes.
The purposes of this study were to: (1) develop profiles of WRB for moderately impaired aphasic adult clients and examine these profiles for evidence that reflects the level of breakdown in the word retrieval process, and (2) determine potential treatment applications derived from the study of WRBs of moderately aphasic speakers.
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Li, Zhihan. "Improvement to Chinese information retrieval by incorporating word segmentation and query expansion." Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/30422/1/Zhihan_Li_Thesis.pdf.
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The increasing diversity of the Internet has created a vast number of multilingual resources on the Web. A huge number of these documents are written in various languages other than English. Consequently, the demand for searching in non-English languages is growing exponentially. It is desirable that a search engine can search for information over collections of documents in other languages. This research investigates the techniques for developing high-quality Chinese information retrieval systems. A distinctive feature of Chinese text is that a Chinese document is a sequence of Chinese characters with no space or boundary between Chinese words. This feature makes Chinese information retrieval more difficult since a retrieved document which contains the query term as a sequence of Chinese characters may not be really relevant to the query since the query term (as a sequence Chinese characters) may not be a valid Chinese word in that documents. On the other hand, a document that is actually relevant may not be retrieved because it does not contain the query sequence but contains other relevant words. In this research, we propose two approaches to deal with the problems. In the first approach, we propose a hybrid Chinese information retrieval model by incorporating word-based techniques with the traditional character-based techniques. The aim of this approach is to investigate the influence of Chinese segmentation on the performance of Chinese information retrieval. Two ranking methods are proposed to rank retrieved documents based on the relevancy to the query calculated by combining character-based ranking and word-based ranking. Our experimental results show that Chinese segmentation can improve the performance of Chinese information retrieval, but the improvement is not significant if it incorporates only Chinese segmentation with the traditional character-based approach. In the second approach, we propose a novel query expansion method which applies text mining techniques in order to find the most relevant words to extend the query. Unlike most existing query expansion methods, which generally select the highly frequent indexing terms from the retrieved documents to expand the query. In our approach, we utilize text mining techniques to find patterns from the retrieved documents that highly correlate with the query term and then use the relevant words in the patterns to expand the original query. This research project develops and implements a Chinese information retrieval system for evaluating the proposed approaches. There are two stages in the experiments. The first stage is to investigate if high accuracy segmentation can make an improvement to Chinese information retrieval. In the second stage, a text mining based query expansion approach is implemented and a further experiment has been done to compare its performance with the standard Rocchio approach with the proposed text mining based query expansion method. The NTCIR5 Chinese collections are used in the experiments. The experiment results show that by incorporating the text mining based query expansion with the hybrid model, significant improvement has been achieved in both precision and recall assessments.
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Pera, Maria Soledad. "Improving library searches using word-correlation factors and folksonomies /." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2765.pdf.
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Symonds, Michael J. "A tensor encoding model of word meaning : theory and application to information retrieval." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/60567/1/Michael_Symonds_Thesis.pdf.
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This project was a step forward in developing and evaluating a novel, mathematical model that can deduce the meaning of words based on their use in language. This model can be applied to a wide range of natural language applications, including the information seeking process most of us undertake on a daily basis.
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Alexopoulou, Dimitra. "Word-sense disambiguation in biomedical ontologies." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-62843.
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With the ever increase in biomedical literature, text-mining has emerged as an important technology to support bio-curation and search. Word sense disambiguation (WSD), the correct identification of terms in text in the light of ambiguity, is an important problem in text-mining. Since the late 1940s many approaches based on supervised (decision trees, naive Bayes, neural networks, support vector machines) and unsupervised machine learning (context-clustering, word-clustering, co-occurrence graphs) have been developed. Knowledge-based methods that make use of the WordNet computational lexicon have also been developed. But only few make use of ontologies, i.e. hierarchical controlled vocabularies, to solve the problem and none exploit inference over ontologies and the use of metadata from publications.
This thesis addresses the WSD problem in biomedical ontologies by suggesting different approaches for word sense disambiguation that use ontologies and metadata. The "Closest Sense" method assumes that the ontology defines multiple senses of the term; it computes the shortest path of co-occurring terms in the document to one of these senses. The "Term Cooc" method defines a log-odds ratio for co-occurring terms including inferred co-occurrences. The "MetaData" approach trains a classifier on metadata; it does not require any ontology, but requires training data, which the other methods do not. These approaches are compared to each other when applied to a manually curated training corpus of 2600 documents for seven ambiguous terms from the Gene Ontology and MeSH. All approaches over all conditions achieve 80% success rate on average. The MetaData approach performs best with 96%, when trained on high-quality data. Its performance deteriorates as quality of the training data decreases. The Term Cooc approach performs better on Gene Ontology (92% success) than on MeSH (73% success) as MeSH is not a strict is-a/part-of, but rather a loose is-related-to hierarchy. The Closest Sense approach achieves on average 80% success rate.
Furthermore, the thesis showcases applications ranging from ontology design to semantic search where WSD is important.
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Al, Tayyar Musaid Seleh. "Arabic information retrieval system based on morphological analysis (AIRSMA) : a comparative study of word, stem, root and morpho-semantic methods." Thesis, De Montfort University, 2000. http://hdl.handle.net/2086/4126.
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Enright, Morgan Elaine. "The facilitative effects of drawing and gesturing on word retrieval for people with aphasia." Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1594.
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In order to verbally communicate successfully, people need the ability to retrieve a desired word. However, the inability to do this, called “anomia,” is a common impairment for people with aphasia, and frequently persists into the chronic stage of recovery. Strategies that facilitate verbal expression may reduce or compensate for instances of anomia. Verbal strategies, such as Semantic Feature Analysis (SFA) have been researched extensively and shown to be effective. Nonverbal strategies, such as drawing and gesture, have research on their effects as a substitution for verbalization, but less on their facilitative effects. However, the research suggests they may work in a similar manner to verbal approaches, by activating semantic networks. Thus, the facilitative effects of nonverbal strategies should be explored further. The aim of this experiment was to determine the facilitative effects of drawing and gesturing during a picture naming task in one participant with chronic aphasia. Results revealed that all conditions evaluated, drawing, gesture, and wait (control), produced improvements in the picture naming task. However, contrary to expectations, the facilitated conditions (i.e. drawing and gesture) did not create more effects than the unfacilitated condition (i.e. wait). This finding may indicate the benefits of a factor common to all conditions. Further results of this study and directions for future research are discussed.
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Osorio, Bretti Cristian. "Using word embeddings and domain specific data for information retrieval in the Swedish consumer health domain." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281706.
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The amount of information in most of the world’s systems is increasing rapidly. To be able to find relevant information in the vast amount of data, good information retrieval (IR) algorithms are needed. IR algorithms can be constructed and tuned to perform well in different domains. One such domain is consumerhealth, a domain in which regular people (consumers) search for medical information. One way to improve IR algorithms is to use word embeddings (WE). WE are vector representations of words in such a way that similar words have similar vectors. Previous research has shown that using WE in IR gives promising results. In this thesis, an IR algorithm based on WE is implemented. This is evaluated in the domain of Swedish consumer health queries by using query-logs from a Swedish digital healthcare provider as evaluation data. The popular BM25 algorithm was used as a baseline algorithm. A linear combination of the WE algorithm and the BM25 algorithm, the mixture model (MM), was also implemented. Experiments revealed that a MM that is mostly similar to the WE is preferable. When evaluating these three algorithms, it became apparent that the MM algorithm performed best overall. Four different evaluation metrics were used and the MM algorithm was the second-best in three and the best in one of these. Since the MM algorithm was most similar to the WE algorithm, it indicates that integrating WE in IR has a positive effect. Although further research in the area is recommended to confirm these initial findings, this thesis indicates that WE can potentially improve IR in the domain of Swedish consumer health.Mängden information i de flesta av världens system ökar snabbt. För att kunna hitta relevant information i denna stora mängd data krävs bra informationssökningsalgoritmer (eng: information retrieval, IR). IR-algoritmer kan konstrueras och justeras så att de fungerar bra inom olika sökområden. Ett sådant område är konsumenthälsa, ett område där vanliga människor (konsumenter) söker efter medicinsk information. Ett sätt att förbättra IR-algoritmer är att använda ordinbäddningar (eng: word embeddings, WE). WE är vektorrepresentationer av ord som konstrueras så att liknande ord har liknande vektorer. Tidigare forskning har visat att användning av WE i IR ger lovande resultat. I den här uppsatsen implementeras en IR-algoritm baserad på WE. Detta utvärderas inom området för svenska konsumenthälsofrågor med hjälp av sökloggar från en svensk digital vårdgivare som utvärderingsdata. Den populära BM25-algoritmen användes som referensalgoritm. En linjärkombination av WE-algoritmen och BM25-algoritmen, mixture model (MM), implementerades också. Experimenten avslöjade att en MM som mest liknar WE är att föredra. Vid utvärderingen av dessa tre algoritmer visade det sig att MM algoritmen totalt sett presterade bäst. Fyra olika utvärderingsmått användes och MM-algoritmen var den näst bästa i tre och den bästa i ett. Eftersom MM algoritmen var mest lik WE-algoritmen, indikerar det att användningen av WEi IR har en positiv effekt. Även om ytterligare forskning inom området rekommenderas för att bekräfta dessa preliminära upptäckter, pekar denna uppsats på att WE potentiellt kan förbättra IR inom området svenska konsumenthälsofrågor.
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Boynuegri, Akif. "Cross-lingual Information Retrieval On Turkish And English Texts." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611903/index.pdf.
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In this thesis, cross-lingual information retrieval (CLIR) approaches are comparatively evaluated
for Turkish and English texts. As a complementary study, knowledge-based methods
for word sense disambiguation (WSD), which is one of the most important parts of the CLIR
studies, are compared for Turkish words.
Query translation and sense indexing based CLIR approaches are used in this study. In query
translation approach, we use automatic and manual word sense disambiguation methods and
Google translation service during translation of queries. In sense indexing based approach,
documents are indexed according to meanings of words instead of words themselves. Retrieval
of documents is performed according to meanings of the query words as well. During
the identification of intended meaning of query terms, manual and automatic word sense disambiguation
methods are used and compared to each other.
Knowledge based WSD methods that use different gloss enrichment techniques are compared
for Turkish words. Turkish WordNet is used as a primary knowledge base and English
WordNet and Turkish Wikipedia are employed as enrichment resources. Meanings of
words are more clearly identified by using semantic relations defined in WordNets and Turkish
Wikipedia. Also, during calculation of semantic relatedness of senses, cosine similarity
metric is used as an alternative metric to word overlap count. Effects of using cosine similarity
metric are observed for each WSD methods that use different knowledge bases.
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Wilbanks, Amie L. "The Fleeting Effects of Retrieval Cue Attributes in the PIER2 Memory Model." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000159.
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Grassly, J. "Facilitating word retrieval in people with aphasia : an exploration of the relationship between language and neuropsychological processing." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1396006/.
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Background: The challenge of understanding word retrieval is one that has long been the subject of investigation in aphasia therapy research, and has been confounded by the finding that people with similar patterns of language impairment can respond in different ways to the same therapy approach. Consideration has now turned to factors other than just language processes when planning intervention, including extra-linguistic cognitive processes, and the provision, and type, of feedback given. Aims: To investigate the language and neuropsychological processing abilities of people with aphasia, and to examine how these abilities relate to response to facilitation and feedback. Methods & Procedures: Eight adults with aphasia, aged between 25 and 81, participated in a case series design. A novel battery of language and neuropsychological assessments was administered. Five facilitation studies were carried out, in which the effect on word retrieval at a later point in time was investigated for different linguistic cues and use of feedback. Outcomes & Results: The differences in participants’ profiles enabled significant theoretically-motivated correlations to be identified between several aspects of processing within the areas under investigation: language, facilitation, neuropsychology and feedback. Conclusions & Implications: Assessments of memory and attention show potential for use within a wider battery administered by clinicians. Measures of executive function were less straightforward, due in part to its multifaceted nature; assessments of this domain should therefore be considered on an individual basis with regards to the underlying processes measured. Language skills alone are not able to predict response to facilitation. Facilitation was found to be a robust and valid tool and it is suggested that it may be used as a reliable probe tool to identify appropriate therapy techniques. Clinician-delivered feedback can improve word retrieval for responses that were initially incorrect; promoting self-feedback following correct responses can result in superior delayed naming.
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Hanly, Sarah M. "Exploring the cognitive underpinnings of word retrieval deficits in dyslexia using the tip-of -the-tongue paradigm." Diss., St. Louis, Mo. : University of Missouri--St. Louis, 2008. http://etd.umsl.edu/r3021.
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Sotiropoulou, Drosopoulou Christina. "Speed of word retrieval across neurotypical and aphasic participants : an investigation of novel assessment and treatment methods." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/speed-of-word-retrieval-across-neurotypical-and-aphasic-participants-an-investigation-of-novel-assessment-and-treatment-methods(f949ed93-7f56-48bb-888d-8db4c54a1e4c).html.
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Word finding difficulties (WFD) and slowing down both in linguistic comprehension and production are standard characteristics of people as they grow older. WFD also commonly occur in aphasia and are considered one of the most pervasive symptoms affecting stroke participants’ everyday communication. Research on older adults’ WFD has traditionally focused on production of single words when completing picture naming tasks, while very little is known about how much these WFD can compromise connected speech. Similarly, while picture naming tasks have typically been used for assessing and treating word finding problems in clinical practice, there is a dearth of studies in the aphasiological literature investigating the relationship between confrontation naming and connected speech tasks. The thesis investigated whether a newly-developed method/treatment targeting both speed and accuracy (‘repeated increasingly speeded presentation’ - RISP) in picture naming was more effective in (a) speeding up participants without compromising accuracy, and (b) improving the use of the trained/treated names in connected speech, compared to a standard method/therapy (‘standard presentation’ - SP) which targeted accuracy alone. English-speaking, elderly participants (n=27 at Chapter 3, n= 21 at Chapter 4) and participants with aphasia of varying severity and subtype (n=5 at Chapter 5 and n=20 at Chapter 6) were asked to carry out picture naming tasks/picture naming treatments and composite picture description tasks where the composite pictures included the trained/treated items. As for the neurotypical participants, words which were retrieved more quickly in picture naming tasks were also those which were more readily available and produced in connected speech tasks. Compared to SP, RISP was found to be significantly more effective in significantly reducing picture naming latencies without inducing a speed-accuracy trade-off and with lasting effects. Finally, SP was as effective in promoting retrieval in connected speech as RISP. As for the clinical population, compared to SP, RISP was significantly more effective in improving picture naming accuracy and in maintaining the reduced RTs in the long term. In comparison to the SP, RISP crucially led to significantly higher carry-over of targeted items to connected speech. The thesis findings underlined the effectiveness of a more demanding single word training method/treatment in improving lexical retrieval in confrontation naming for neurotypical participants and in enhancing connected speech for participants with aphasia.
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Morgart, Arianna Paige. "Lexical access in aphasia: impacts of phonological neighborhood density on accuracy of word production." Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1704.
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Verbal communication relies heavily on the ability to effortlessly produce intended words to express a meaning. This capacity is frequently impaired in individuals with aphasia, and impairment often lasts well into the chronic stages. However, the nature of anomia can vary. Phonological neighborhood density (PND) is one feature of words which has been shown to impact the ease of retrieval in speakers with aphasia; words with more similar-sounding neighbors are easier to retrieve because the neighbors help activate the target. However, it is unclear how different types of lexical access breakdowns affect the impact of PND. The aim of this project was to analyze the relationship between word retrieval accuracy, speech error patterns, and PND in individuals with aphasia. Twenty-two participants with various types and severities of aphasia named 200 single-syllable line drawings. WebFit, an online software program designed to fit naming data to a theoretical model of word retrieval, was used to characterize participants' error patterns by calculating the strength of connections within the lexicon, as well as the rate of decay. Analyses confirmed previous findings that participants with all types of breakdown achieved lower rates of overall accuracy. Weaker connections between semantic knowledge and words resulted in a more errors that were close to the target, relative to errors with no relationship to the target. Individuals with more severe impairments of the semantic-lexical connections and the lexical-phonological connections produced words with many neighbors more accurately than words with fewer neighbors. Implications for initial therapy target selection and directions for further research are discussed.
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Edizel, Necati Bora. "Word embeddings with applications to web search and advertising." Doctoral thesis, Universitat Pompeu Fabra, 2019. http://hdl.handle.net/10803/669622.
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Word embeddings are a building block of many practical applications across NLP and related disciplines. In this thesis, we present theoretical analysis and algorithms to learn word embeddings. Moreover, we present applications of word embeddings that concern Web Search and Advertising.
We start by presenting theoretical insights for one the most popular algorithm to learn word embeddings \textit{word2vec}. We also model \textit{word2vec} in Reinforcement Learning framework and showed that it's an off-policy learner with a fixed behavior policy.
Then we present an off-policy learning algorithm $word2vec_{\pi}$ that uses \textit{word2vec} as a behavior policy.
%With extensive experimentation, we show that the proposed method performs better than \textit{word2vec}.
Then, we present a method to learn word embeddings that are resilient to misspellings. Existing word embeddings have limited applicability to malformed texts, which contain a non-negligible amount of out-of-vocabulary words. We propose a method combining FastText with subwords and a supervised task of learning misspelling patterns. In our method, misspellings of each word are embedded close to their correct variants.
Lastly, we propose two novel approaches (one working at the character level and the other working at word level) that use deep convolutional neural networks for a central task in NLP, semantic matching. We experimentally showed the effectiveness of our approach using click-through rate prediction task for Sponsored Search.Dins del món del Processament del Llenguatge Natural (NLP) i d’altres camps relacionats amb aquest àmbit, les representaciones latents de paraules (word embeddings) s'han convertit en una tecnologia fonamental per a desenvolupar aplicacions pràctiques. En aquesta tesi es presenta un anàlisi teòric d’aquests word embeddings així com alguns algoritmes per a entrenar-los. A més a més, com a aplicació pràctica d’aquesta recerca també es presenten aplicacions per a cerques a la web i màrqueting. Primer, s’introdueixen alguns aspectes teòrics d’un dels algoritmes més populars per a aprendre word embeddings, el word2vec. També es presenta el word2vec en un context de Reinforcement Learning demostrant que modela les normes no explícites (off-policy) en presència d’un conjunt de normes (policies) de comportament fixes. A continuació, presentem un nou algoritme de d’aprenentatge de normes no explícites (off-policy), $word2vec_{\pi}$, com a modelador de normes de comportament. La validació experimental corrobora la superioritat d’aquest nou algorithme respecte \textit{word2vec}. Segon, es presenta un mètode per a aprendre word embeddings que són resistents a errors d’escriptura. La majoria de word embeddings tenen una aplicació limitada quan s’enfronten a textos amb errors o paraules fora del vocabulari. Nosaltres proposem un mètode combinant FastText amb sub-paraules i una tasca supervisada per a aprendre patrons amb errors. Els resultats proven com les paraules mal escrites estan pròximes a les correctes quan les comparem dins de l’embedding. Finalment, aquesta tesi proposa dues tècniques noves (una a nivell de caràcter i l’altra a nivell de paraula) que empren xarxes neuronals (DNNs) per a la tasca de similaritat semàntica. Es demostra experimentalment que aquests mètodes són eficaços per a la predicció de l’eficàcia (click-through rate) dins del context de cerces patrocinades.
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Blackett, Deena Schwen. "The Effects of Emotional Stimuli on Language Processing in Aging Adults and People with Aphasia." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618404969127489.
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Ahlgren, Per. "The effects of indexing strategy-query term combination on retrieval effectiveness in a Swedish full text database." Doctoral thesis, University College of Borås, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171411.
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This thesis deals with Swedish full text retrieval and the problem of morphological variation of query terms in thedocument database. The study is an information retrieval experiment with a test collection. While no Swedish testcollection was available, such a collection was constructed. It consists of a document database containing 161,336news articles, and 52 topics with four-graded (0, 1, 2, 3) relevance assessments. The effects of indexing strategy-query term combination on retrieval effectiveness were studied. Three of five testedmethods involved indexing strategies that used conflation, in the form of normalization. Further, two of these threecombinations used indexing strategies that employed compound splitting. Normalization and compound splittingwere performed by SWETWOL, a morphological analyzer for the Swedish language. A fourth combinationattempted to group related terms by right hand truncation of query terms. A search expert performed the truncation.The four combinations were compared to each other and to a baseline combination, where no attempt was made tocounteract the problem of morphological variation of query terms in the document database. Two situations were examined in the evaluation: the binary relevance situation and the multiple degree relevancesituation. With regard to the binary relevance situation, where the three (positive) relevance degrees (1, 2, 3) weremerged into one, and where precision was used as evaluation measure, the four alternative combinationsoutperformed the baseline. The best performing combination was the combination that used truncation. Thiscombination performed better than or equal to a median precision value for 41 of the 52 topics. One reason for therelatively good performance of the truncation combination was the capacity of its queries to retrieve different partsof speech. In the multiple degree relevance situation, where the three (positive) relevance degrees were retained, retrievaleffectiveness was taken to be the accumulated gain the user receives by examining the retrieval result up to givenpositions. The evaluation measure used was nDCG (normalized cumulated gain with discount). This measurecredits retrieval methods that (1) rank highly relevant documents higher than less relevant ones, and (2) rankrelevant (of any degree) documents high. With respect to (2), nDCG involves a discount component: a discount withregard to the relevance score of a relevant (of any degree) document is performed, and this discount is greater andgreater, the higher position the document has in the ranked list of retrieved documents. In the multiple degree relevance situation, the five combinations were evaluated under four different user scenarios,where each scenario simulated a certain user type. Again, the four alternative combinations outperformed thebaseline, for each user scenario. The truncation combination had the best performance under each user scenario.This outcome agreed with the performance result in the binary relevance situation. However, there were alsodifferences between the two relevance situations. For 25 percent of the topics and with regard to one of the four userscenarios, the set of best performing combinations in the binary relevance situation was disjunct from the set of bestperforming combinations in the multiple degree relevance situation. The user scenario in question was such thatalmost all importance was placed on highly relevant documents, and the discount was sharp. The main conclusion of the thesis is that normalization and right hand truncation (performed by a search expert)enhanced retrieval effectiveness in comparison to the baseline, irrespective of which of the two relevance situationswe consider. Further, the three indexing strategy-query term combinations based on normalization were almost asgood as the combination that involves truncation. This holds for both relevance situations.QC 20150813
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Quimby, Megan. "Word retrieval in bilingual individuals: how do language, test type, and self-reported fluency relate to naming accuracy in English and Hebrew." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12196.
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Thesis (M.S.)--Boston UniversityBackground: Although research on lexical access in Hebrew-English bilinguals exists, there is a need to quantify and determine if proficiency correlates with scores on language tasks like naming in structurally different languages, such as Hebrew and English. Objective: The aim of this study is to determine if language, test type, and self-reported proficiency is reflected in Hebrew-English bilinguals' naming ability in the two languages. Methods: Twenty healthy Hebrew-English bilinguals completed the Mini Mental State Examination (MMSE), the Language Use Questionnaire (LUQ), the Boston Naming Test (BNT), a Hebrew naming test (Kave, 2005), a 100-item category picture naming task, and category generation in both languages. Results: There was a significant effect of language and test type on accuracy scores on picture naming tests. While language did not have a significant effect on category generation, category had a significant effect on correct words, means semantic cluster score, and mean semantic switching score. There were several language proficiency variables that were significantly correlated with naming tasks in English (Language Ability Rating (LAR), Confidence, Lifetime Exposure, Education History), yet LUQ proficiency variables were only significantly correlated with Kave's test (LAR, Education History) on the Hebrew naming tasks. Conclusion: It appears that confrontation-naming assessments result in more variable performance in English and Hebrew than fluency tests. Based on correlations between LUQ variables and Hebrew naming performance, Kave's test appears to be the only test that captures the unique aspects that allow individuals to be proficient in Hebrew. The BNT is a useful measure for examining English naming. Therefore, using the BNT and Kave's Hebrew naming test appears to be the most effective in measuring naming performance in Hebrew-English bilinguals. Significant LUQ variables in English and Hebrew indicate that self-reported acquisition patterns and lifetime usage provide valuable information regarding naming performance.
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Holmgren, Helena, and Sandra Hammarström. "Kompensatoriska strategier för ordmobiliseringssvårigheter vid Alzheimers sjukdom : En fallstudie med enspråkiga och flerspråkiga personer." Thesis, Uppsala universitet, Logopedi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-212889.
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Sweden is getting an aging population and with this comes an increase in neurodegenerative diseases such as Alzheimer’s disease (AD). Bilingualism is also on the rise and this may result in an increase of bilingual people suffering from AD. Due to the linguistic deterioration associated with the illness people with AD, bilingual and monolingual, will be an increasing patient group with speech and language pathologists (SLPs). Word retrieval difficulty is an early symptom of the disease and several strategies to compensate for this have been observed (e.g. fillers, circumlocutions and semantic parafasias). The effectiveness of these strategies has not yet been established. With this background this study attempts to investigate which strategies are used by monolingual and bilingual people with AD to compensate for word retrieval difficulties. A case study was performed on four participants with AD, two of which were monolingual and two were bilingual. Spontaneous speech was collected by means of a semi-structured conversation and a short story was produced with picture support. The results showed that there were individual differences in terms of the compensatory strategies. The results indicated that the strategies’ effectiveness depended on the progression of the disease in each individual. No differences between the bilingual participants’ first and second language were observed with exception to the usage of code switching. The picture support seemed to be of some help for the participants to achieve better fluency of speech since word retrieval difficulties seemed to decrease. The conclusion is that SLPs could make their patients aware of several different strategies to compensate for word retrieval difficulties to discover what is the most effective for each individual; furthermore pictures can be used to help clients’ narratives.Sverige får en allt äldre befolkning. Detta för med sig ökande antal personer med Alzheimers sjukdom (AD). Då sjukdomen innebär stor språklig påverkan kan denna patientgrupp förväntas öka inom den logopediska vården. Även andelen flerspråkiga i samhället växer, vilket gör att logopeder kommer att ta emot allt fler flerspråkiga äldre patienter. Ordmobiliseringssvårigheter har setts vara ett tidigt symtom vid sjukdomen både hos enspråkiga och flerspråkiga personer. Tidigare forskning har visat att ett flertal kompensatoriska strategier (t.ex. utfyllnader, omskrivningar och utbyten) används för att hantera dessa svårigheter men det är inte klarlagt hur väl dessa strategier fungerar. Därför undersöks i denna studie vilka kompensatoriska strategier som förekommer både hos enspråkiga och flerspråkiga personer med AD. En fallstudie genomfördes på fyra deltagare med AD, varav två enspråkiga och två flerspråkiga. Spontantal samlades in genom ett semistrukturerat samtal och en kortare berättelse genomfördes med hjälp av bildstöd. Resultaten visade att effektiviteten i de använda strategierna skiljer sig mellan individer. Hur långt deltagarna kommit i sjukdomsförloppet verkade dock ha betydelse. Ingen större skillnad mellan de flerspråkiga deltagarnas båda språk observerades förutom gällande användning av kodväxling. Deltagarna verkade i viss mån vara hjälpta av bildstöd för att uppnå bättre talflyt eftersom ordmobiliseringsproblematiken tycktes minska. Slutsatser som drogs är att logopeder kan medvetandegöra patienter och närstående om ett flertal olika strategier för att hitta den strategi som fungerar bäst för den individuella patienten samt att bildstöd kan användas för att underlätta berättande.
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Garcia, Ian. "Eliminating Redundant and Less-informative RSS News Articles Based on Word Similarity and A Fuzzy Equivalence Relation." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1688.pdf.
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Stielow, Anna Katharina Verfasser], Eva [Gutachter] [Belke, and Ralf [Gutachter] Klabunde. "The contribution of executive functions to performance in word retrieval tasks in aphasic patients and healthy controls / Anna Katharina Stielow ; Gutachter: Eva Belke, Ralf Klabunde." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1129452336/34.
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Clinchant, Stéphane. "Modèles probabilistes pour les fréquences de mots et la recherche d'information." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT046/document.
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Nous nous intéressons à la fois à la modélisation des fréquences des mots dans les collections textuelles et aux modèles probabilistes de recherche d'information (RI). Concernant les modèles statistiques de fréquences de mots, nous portons notre attention sur l'étude du phénomène de rafale (burstiness). Nous établissons une propriété sur les distributions de probabilité caractérisant leur capacité à modéliser ce phénomène et nous étudions ensuite les distributions Beta Negative Binomial et Log-Logistique pour la modélisation des fréquences de mots. Nous portons ensuite notre attention sur les modèles probabilistes de RI et leur propriétés fondamentales. Nous pouvons montrer que les modèles classiques ne reposent pas sur des lois de probabilité en rafale, même si des propriétés fondamentales comme la concavité des modèles permettent implicitement de le prendre en compte. Nous introduisons ensuite une nouvelle famille de modèles probabiliste pour la recherche d'information, fondé sur la notion d'information de Shannon et qui permet d'établir un lien conséquent entre les propriétés importantes des modèles de RI et le phénomène de rafale. Enfin, nous étudions empiriquement et théoriquement les modèles de rétro-pertinence. Nous proposons un cadre théorique qui permet ainsi d'expliquer leurs caractéristiques empiriques et leur performances. Ceci permet entre autres de mettre en avant les propriétés importantes des modèles de retro-pertinence et de montrer que certains modèles de référence sont déficientsThe present study deals with word frequencies distributions and their relation to probabilistic Information Retrieval (IR) models. We examine the burstiness phenomenon of word frequencies in textual collections. We propose to model this phenomenon as a property of probability distributions and we study the Beta Negative Binomial and Log-Logistic distributions to model word frequencies. We then focus on probabilistic IR models and their fundamental properties. Our analysis reveals that probability distributions underlying most state-of-the-art models do not take this phenomenon into account , even if fundamental properties of IR models such as concavity enable implicitly to take it into account. We then introduce a novel family of probabilistic IR model, based on Shannon information. These new models bridge the gap between significant properties of IR models and the burstiness phenomenon of word frequencies. Lastly, we study empirically and theoretically pseudo relevance feedback models. We propose a theoretical framework which explain well the empirical behaviour and performance of pseudo relevance feedback models. Overall, this highlights interesting properties for pseudo relevance feedback and shows that some state-of-the-art model are inadequate
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PISONI, ALBERTO. "Investigating the neural correlates of language production by means of TDCS." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/52583.
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Language production is one of the most complex cognitive – motor skills developed by homo sapiens throughout evolution to allow inter-personal and intra-personal communication (Indefrey and Levelt, 2000). A great number of cortical regions have adapted to support this high-speed combination of muscular and mental processes, in order to correctly generate the intended utterances in different contexts and situations. The neural organization of language processing is a thorny matter, that in the last decades has been investigated with a number of different methods ranging from functional imaging (fMRI, PET; see Gernsbacher & Kashack, 2003; Price, 2010; 2012 for reviews) neurophysiology (EEG, ERP, MEG, see Ganushchak et al., 2011 for a review), lesion studies (for a review see Turkeltaub et al., 2011) and non-invasive brain stimulation (such as transcranial magnetic stimulation, TMS, and transcranial direct current stimulation, tDCS, Devlin and Watkins, 2007; Monti et al., 2012 for reviews). Overall these studies have identified specific areas differently involved in language sub-processes (for a review see Price, 2012; Indefrey, 2011). As a new methodology to investigate the relationship between cortical areas and behavioural performance in cognitive tasks, including language, tDCS has been increasingly used in the last decade (Vallar & Bolognini, 2011). This technique relies on a sub-threshold polarization or de-polarization of neurons that leads to a modulation of cortical excitability and plasticity (Nitsche & Paulus, 2011). Due to its ease of application even in clinical settings, the potential of this tool in neuro-scientific investigation seems wide, but there is no precise knowledge of its mechanisms and effects on cognitive functions. The aim of the present study is to test tDCS effects on language production, to explore when this technique can be applied and to deeply investigate the mechanisms that lead to behavioural changes. In particular, since one of the classification criteria in aphasia is verbal fluency, in study
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1 I investigated the effects of anodal tDCS on a verbal fluency task, aiming at developing a possible protocol to apply on clinical populations. To assess whether stimulation could modulate language production, healthy subjects performed a verbal fluency task both on phonemic and semantic cue immediately after real or sham stimulation. Since this requires the activity of a distributed network, including, among others, the left inferior frontal gyrus (LIFG), the left pre-motor cortex (LPMC), the left inferior and superior temporal gyri (LITG, LSTG) and the bilateral occipital-temporal sulci (Birn et al., 2010), and given that widespread effects of tDCS on functional networks need further clarification, in study 2 I investigated how electrical non-invasive brain stimulation affects cortical excitability by means of a TMS- EEG and tDCS combination, assessing how tDCS modulates cortical excitability and, accordingly, behavioural performance on verbal fluency. An open issue, indeed, is how stimulation enhances the activity of functional networks during task execution. Few recent studies addressed this question, but they generally rely on imaging data (Meinzer et al., 2012, 2013; Holland et al., 2011;). Hence, I tested how cortical excitability is modified after anodal tDCS applied over the LIFG in a functionally connected area, namely the LPMC (BA6) and in a region not involved in verbal fluency, the left superior parietal lobe (LSPL, BA7), and whether these changes could explain the effects of tDCS on task performance. Then, in study 3 and 4 and 5, I tested whether tDCS could be a useful tool to investigate language processes in healthy subjects. In particular, in study 3 and 4 I focused on semantic and phonological interference in picture naming tasks. The functional locus of the semantic interference (SI) effect, indeed, is still not clear (Finkbeiner and Caramazza, 2006; Schnur et al., 2006; 2009; Schnurr and Martin, 2012) and the role of the LIFG and LSTG in this effect is still under debate (Schnur et al., 2006; 2009). To test the different hypotheses underlying SI effect, I investigated the effects of anodal stimulation on the two aforementioned areas in a naming task in which
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semantic context was manipulated (“blocked naming task”, Belke et al., 2005). Similarly, frontal and temporal regions seem to be involved in the phonological facilitation (PF) effect observed in naming (De Zubicaray et al., 2002; De Zubicaray and McMahon, 2009; Zhao et al., 2012; Damian & Bowers, 2009; Meyer and Schriefers, 1991; Scrhiefers et al., 1990). A picture word interference paradigm (PWI) was then administered after anodal stimulation of the LIFG and LSTG, and the effect of stimulation on PF was assessed. Finally, since proper name retrieval decreases with aging (Evrard et al., 2002), it would be of high interest to develop protocols improving this ability: this is the topic of study 5.
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Karmakar, Saurav. "Syntactic and Semantic Analysis and Visualization of Unstructured English Texts." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/cs_diss/61.
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People have complex thoughts, and they often express their thoughts with complex sentences using natural languages. This complexity may facilitate efficient communications among the audience with the same knowledge base. But on the other hand, for a different or new audience this composition becomes cumbersome to understand and analyze. Analysis of such compositions using syntactic or semantic measures is a challenging job and defines the base step for natural language processing.
In this dissertation I explore and propose a number of new techniques to analyze and visualize the syntactic and semantic patterns of unstructured English texts.
The syntactic analysis is done through a proposed visualization technique which categorizes and compares different English compositions based on their different reading complexity metrics. For the semantic analysis I use Latent Semantic Analysis (LSA) to analyze the hidden patterns in complex compositions. I have used this technique to analyze comments from a social visualization web site for detecting the irrelevant ones (e.g., spam). The patterns of collaborations are also studied through statistical analysis.
Word sense disambiguation is used to figure out the correct sense of a word in a sentence or composition. Using textual similarity measure, based on the different word similarity measures and word sense disambiguation on collaborative text snippets from social collaborative environment, reveals a direction to untie the knots of complex hidden patterns of collaboration.
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Zayour, Iyad. "Information retrieval over the World Wide Web." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq22023.pdf.
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Lee, Kwok-wai Joseph, and 李國偉. "Information retrieval on the world wide web." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B42576192.
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Lee, Kwok-wai Joseph. "Information retrieval on the world wide web." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42576192.
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El, Mahdaouy Abdelkader. "Accès à l'information dans les grandes collections textuelles en langue arabe." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAM091/document.
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Face à la quantité d'information textuelle disponible sur le web en langue arabe, le développement des Systèmes de Recherche d'Information (SRI) efficaces est devenu incontournable pour retrouver l'information pertinente. La plupart des SRIs actuels de la langue arabe reposent sur la représentation par sac de mots et l'indexation des documents et des requêtes est effectuée souvent par des mots bruts ou des racines. Ce qui conduit à plusieurs problèmes tels que l'ambigüité et la disparité des termes, etc.Dans ce travail de thèse, nous nous sommes intéressés à apporter des solutions aux problèmes d'ambigüité et de disparité des termes pour l'amélioration de la représentation des documents et le processus de l'appariement des documents et des requêtes. Nous apportons quatre contributions au niveau de processus de représentation, d'indexation et de recherche d'information en langue arabe. La première contribution consiste à représenter les documents à la fois par des termes simples et des termes complexes. Cela est justifié par le fait que les termes simples seuls et isolés de leur contexte sont ambigus et moins précis pour représenter le contenu des documents. Ainsi, nous avons proposé une méthode hybride pour l’extraction de termes complexes en langue arabe, en combinant des propriétés linguistiques et des modèles statistiques. Le filtre linguistique repose à la fois sur l'étiquetage morphosyntaxique et la prise en compte des variations pour sélectionner les termes candidats. Pour sectionner les termes candidats pertinents, nous avons introduit une mesure d'association permettant de combiner l'information contextuelle avec les degrés de spécificité et d'unité. La deuxième contribution consiste à explorer et évaluer les systèmes de recherche d’informations permettant de tenir compte de l’ensemble des éléments d’indexation (termes simples et complexes). Par conséquent, nous étudions plusieurs extensions des modèles existants de RI pour l'intégration des termes complexes. En outre, nous explorons une panoplie de modèles de proximité. Pour la prise en compte des dépendances de termes dans les modèles de RI, nous introduisons une condition caractérisant de tels modèle et leur validation théorique. La troisième contribution permet de pallier le problème de disparité des termes en proposant une méthode pour intégrer la similarité entre les termes dans les modèles de RI en s'appuyant sur les représentations distribuées des mots (RDMs). L'idée sous-jacente consiste à permettre aux termes similaires à ceux de la requête de contribuer aux scores des documents. Les extensions des modèles de RI proposées dans le cadre de cette méthode sont validées en utilisant les contraintes heuristiques d'appariement sémantique. La dernière contribution concerne l'amélioration des modèles de rétro-pertinence (Pseudo Relevance Feedback PRF). Étant basée également sur les RDM, notre méthode permet d'intégrer la similarité entre les termes d'expansions et ceux de la requête dans les modèles standards PRF. La validation expérimentale de l'ensemble des contributions apportées dans le cadre de cette thèse est effectuée en utilisant la collection standard TREC 2002/2001 de la langue arabeGiven the amount of Arabic textual information available on the web, developing effective Information Retrieval Systems (IRS) has become essential to retrieve relevant information. Most of the current Arabic SRIs are based on the bag-of-words representation, where documents are indexed using surface words, roots or stems. Two main drawbacks of the latter representation are the ambiguity of Single Word Terms (SWTs) and term mismatch.The aim of this work is to deal with SWTs ambiguity and term mismatch. Accordingly, we propose four contributions to improve Arabic content representation, indexing, and retrieval. The first contribution consists of representing Arabic documents using Multi-Word Terms (MWTs). The latter is motivated by the fact that MWTs are more precise representational units and less ambiguous than isolated SWTs. Hence, we propose a hybrid method to extract Arabic MWTs, which combines linguistic and statistical filtering of MWT candidates. The linguistic filter uses POS tagging to identify MWTs candidates that fit a set of syntactic patterns and handles the problem of MWTs variation. Then, the statistical filter rank MWT candidate using our proposed association measure that combines contextual information and both termhood and unithood measures. In the second contribution, we explore and evaluate several IR models for ranking documents using both SWTs and MWTs. Additionally, we investigate a wide range of proximity-based IR models for Arabic IR. Then, we introduce a formal condition that IR models should satisfy to deal adequately with term dependencies. The third contribution consists of a method based on Distributed Representation of Word vectors, namely Word Embedding (WE), for Arabic IR. It relies on incorporating WE semantic similarities into existing probabilistic IR models in order to deal with term mismatch. The aim is to allow distinct, but semantically similar terms to contribute to documents scores. The last contribution is a method to incorporate WE similarity into Pseud-Relevance Feedback PRF for Arabic Information Retrieval. The main idea is to select expansion terms using their distribution in the set of top pseudo-relevant documents along with their similarity to the original query terms. The experimental validation of all the proposed contributions is performed using standard Arabic TREC 2002/2001 collection
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Beryoza, Dmitriy. "Dynamic data retrieval on the world wide web." FIU Digital Commons, 2000. http://digitalcommons.fiu.edu/etd/1654.
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Methods for accessing data on the Web have been the focus of active research over the past few years. In this thesis we propose a method for representing Web sites as data sources. We designed a Data Extractor data retrieval solution that allows us to define queries to Web sites and process resulting data sets. Data Extractor is being integrated into the MSemODB heterogeneous database management system. With its help database queries can be distributed over both local and Web data sources within MSemODB framework.
Data Extractor treats Web sites as data sources, controlling query execution and data retrieval. It works as an intermediary between the applications and the sites. Data Extractor utilizes a two-fold "custom wrapper" approach for information retrieval. Wrappers for the majority of sites are easily built using a powerful and expressive scripting language, while complex cases are processed using Java-based wrappers that utilize specially designed library of data retrieval, parsing and Web access routines. In addition to wrapper development we thoroughly investigate issues associated with Web site selection, analysis and processing.
Data Extractor is designed to act as a data retrieval server, as well as an embedded data retrieval solution. We also use it to create mobile agents that are shipped over the Internet to the client's computer to perform data retrieval on behalf of the user. This approach allows Data Extractor to distribute and scale well.
This study confirms feasibility of building custom wrappers for Web sites. This approach provides accuracy of data retrieval, and power and flexibility in handling of complex cases.
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He, Bing. "Efficient information retrieval from the World Wide Web." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33938.pdf.
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Johnstone, S. "Peer to peer information retrieval in a small world." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437430.
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Manuel, Ryan A. "Learning the process of World Wide Web data retrieval." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33288.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (leaf 65).
We develop a method for extracting and internalizing web site form submissions which we refer to as web operations. To begin the process, a user performs a sample submission of the form. From that submission, our system determines all of the necessary information to store the web operation. Through a simple user interface the user can view and modify the web operation to the extent that he wants or needs to. With the operation now stored, the user can invoke the operation without browsing to the web site on which the operation was originally contained. By utilizing the web site information extraction techniques contained in the Haystack information management system, we give the user the option to extract information off of web operation results pages. Thus, when using our system to the fullest extent, a user can invoke web operations and view and make use of the results without viewing any web pages.
by Ryan A. Manuel.
M.Eng.