A reinforcement learning based distributed search algorithm for hierarchical peer-to-peer information retrieval systems

Humans have used electronic information retrieval (IR) systems for more than 50 years as they evolved from experimental systems to full-scale Web search engines and digital libraries. The fields of library and information science (LIS), cognitive science, human factors and computer science have historically been the leading disciplines in conducting research that seeks to model human interaction with IR systems for all kinds of information related behaviors. As technology problems have been mastered, the theoretical and applied framework for studying human interaction with IR systems has evolved from systems-centered to more user-centered, or cognitive-centered approaches. However, cognitive information retrieval (CIR) research that focuses on user interaction with IR systems is still largely under-funded and is often not included at computing and systems design oriented conferences. But CIR-focused research continues, and there are signs that some IR systems designers in academia and the Web search business are realizing that user behavior research can provide valuable insights into systems design and evaluation. The goal of our book is to provide an overview of new CIR research directions. This book does not provide a history of the research field of CIR. Instead, the book confronts new ways of looking at the human information condition with regard to our increasing need to interact with IR systems. The need has grown due to a number of factors, including the increased importance of information to more people in this information age. Also, IR was once considered document-oriented, but has now evolved to include multimedia, text, and other information objects. As a result, IR systems and their complexity have proliferated as users and user purposes for using them have also proliferated. Human interaction with IR systems can often be frustrating as people often lack an understanding of IR system functionality. New more holistic directions in CIR are emerging that conceptualize human-IR system interaction at the human-computer interaction level (taking into account interface issues), the information behavior level (taking into account the role of IR system interaction in the total range of people’s information behaviors), and the

This article discusses a multiple search session model of end-users' interaction with information retrieval systems based on results from an exploratory study investigating end-users' search sessions over time with online public access catalogs (OPAC) or CD-ROM databases at different stages of their information seeking related to a current research project. Interviews were conducted with 200 academic end-users to investigate the occurrence of multiple search sessions. Results show that at the time of the interview, 57% of end-users had conducted multiple search sessions during their research project and 86% of end-users conducted their first search session at the beginning stage of their information-seeking process. Forty-nine percent of end-users had conducted between 1 and 6 search sessions and 8% more than 6 search sessions. Seventy percent of multiple search session end-users' had modified their search terms since their first search session. The implications of the findings for end-user training, information retrieval systems design, and further research are discussed. © 1996 John Wiley & Sons, Inc.

Information Retrieval (IR) systems aim to retrieve data that satisfies certain requirements and constitute an important service in many types of networks, including Delay/Disruption Tolerant Networks (DTNs). In current DTN based IR systems, the data that satisfies a query is assumed to be stored on a single node. Therefore, once a node receives a query in which it has the corresponding data, the query can be resolved completely. However, in scenarios where a query requires data from multiple nodes, these IR systems may fail. Henceforth, in this paper, we propose Distributed Data-Centric Information Retrieval (DDC-IR), a data centric IR system that supports all query types; e.g., continuous and complex. More importantly, it is designed specifically to operate in DTNs. It also incorporates a new packet, aka Query Reply Packet, that includes both a query and one or more replies. We show how this packet facilitates efficient query resolution and enables data centric routing. In addition, it uses caching so that nodes store popular queries that has the effect of speeding up query resolution. We have conducted an extensive simulation study to compare DDC-IR to state of the art IR systems using the popular Random Waypoint model and a trace-file containing student movements on a campus. The results show that DDC-IR is able to resolve 50 % more queries and has an 80 % lower buffer occupancy level than existing IR systems. We also tested DDC-IR in networks with varying sizes. For networks with 100 nodes, DDC-IR is able to resolve queries while current IR systems fail to resolve any queries. In particular, when the number of nodes increases, current IR systems fail to resolve any queries, whilst DDC-IR is able to resolve complex and continuous queries. The influence of the number of sub-queries on query resolution time is also studied. Specifically, when the number of sub-queries in a complex query increases from five to nine, DDC-IR uses 50 % more time to resolve a query. In comparison, prior IR systems fail to resolve any queries.

Purpose – People often engage in different information-seeking strategies (ISSs) within a single information-seeking episode. A critical concern for the design of information retrieval (IR) systems is how to provide support for these different behaviors in a manner which searchers can easily understand, navigate and use, as they move from one ISS to another. The purpose of this paper is to describe a dialogue structure that was implemented in an experimental IR system, in order to address this concern. Design/methodology/approach – The authors conducted a user-centered experiment to evaluate the IR systems. Participants were asked to search for information on two different task types, with four different topics per task, in both the experimental system and a baseline system emulating state-of-the-art IR systems. The authors report here the results related explicitly to the use of the experimental system's dialogue structure. Findings – For one of the task types, most participants followed the search steps as predicted in the dialogue structures, and those who did so completed the task in fewer moves. For the other task type, predicted order of moves was often not followed, but participants again used fewer moves when following the predicted order. Results demonstrate that the dialogue structures the authors designed indeed support effective human information behavior patterns in a variety of ways, and that searchers can effectively use a system which changes to support different ISSs. Originality/value – This study shows that it is both possible and beneficial, to design an IR system which can support multiple ISSs, and that such a system can be understood and used successfully.

F. Wilfrid Lancaster has earned a reputation for greatness in the evaluation of information storage and retrieval systems. Many of his extensive contributions stem from his early experience with the National Library of Medicine (NLM) MEDLARS system. His evaluation of the MEDLARS Demand Search Service in 1966 and 1967 was an important landmark as one of the earliest evaluations of a computer-based retrieval system and as the first application of re-call and precision measures in a large, operational database setting. In 1971, his evaluation of the MEDLARS AIM-TWX system was an important study of early online systems and their direct use by end users. This paper summarizes Lancaster’s two major evaluations of the MEDLARS system, including the information environment at the time and their impact in the field of information science. Examples of Lancaster’s other evaluation work with information retrieval systems are provided, followed by discussion of the textbooks that grew out of his evaluation experience and expertise. The article closes with comments from current and former NLM staff regarding Lancaster’s time at NLM or his influence on their own career.

In modern information retrieval (IR) systems, scoring functions have been extensively adopted for sorting results. For a given document, the rank in sorted result lists with respect to hot searches can be considered as its influence. When a new document comes, can we use such IR systems to evaluate its influence before we insert it into the corpus? Such issue may not be solved very well by current IR systems with inverted indexes. In this paper, an influence measure based on documents’ global rank is proposed, and the inverted index structure has been extended by adding the position milestones for speeding up the ranking calculation. Moreover, a performance study using both real data and synthetic data verifies the effectiveness and the efficiency of our method.

Session search is an Information Retrieval (IR) task which handles a series of queries issued for a search task. In this paper, we propose a novel reinforcement learning style information retrieval framework and develop a new feedback learning algorithm to model user feedback, including clicks and query reformulations, as reinforcement signals and to generate rewards in the RL framework. From a new perspective, we view session search as a cooperative game played between two agents, the user and the search engine. We study the communications between the two agents; they always exchange opinions on whether the current stage of search is relevant and whether we should explore now. The algorithm infers user feedback models by an EM algorithm from the query logs. We compare to several state-of-the-art session search algorithms and evaluate our algorithm on the most recent TREC 2012 to 2014 Session Tracks. The experimental results demonstrates that our approach is highly effective for improving session search accuracy.

Gathering information and making decisions based on retrieved information are the important tasks that every intelligence analyst is doing. User modeling techniques have been exploited to help analysts to search for information effectively. To justify the effects of any user modeling technique on helping analysts retrieve quality documents relevant to their tasks, we need to have a comprehensive evaluation method, which assesses the improvement of retrieval performance and user performance. In this paper, we describe our evaluation of a cognitive user model for information retrieval with regards to retrieval performance. Our user model captures user intent dynamically by analyzing behavioral information from retrieved relevant documents for improving the retrieval performance and user's performance. In this evaluation, we assess the user model's short-term effects on a single query, and the user model's long-term effects on the whole search session. We compare our approach with the best traditional approach for relevance feedback in information retrieval, the Ide dec-hi, which is the approach of modifying queries using term frequency from relevant/non-relevant documents. We use the oldest collection of information retrieval on aerodynamics called CRANFIELD. The results of this evaluation show that by exploring user intent, we achieve competitive performance in the feedback run compared to Ide dec-hi. At the same time, our user model approach offers the advantages of retrieving more quality documents at the initial run compared to the term frequency inverted document frequency (TFIDF) approach. Our results have shown that our user modeling approach can be used to improve efficiency, learnability and interactivity of an information retrieval system.

The recent increase in the volume and variety of video content available online presents growing challenges for video search. Users face increased difficulty in formulating effective queries and search engines must deploy highly effective algorithms to provide relevant results. Although lately much effort has been invested in optimizing video search engine results, relatively little attention has been given to predicting for which queries results optimization is most useful, i.e., predicting which queries will fail. Being able to predict when a video search query would fail is likely to make the video search result optimization more efficient and effective, improve the search experience for the user by providing support in the query formulation process and in this way boost the development of video search engines in general. While insight about a query's performance in general could be obtained using the well-known concept of query performance prediction (QPP), we propose a novel approach for predicting a failure of a video search query in the specific context of a search session. Our 'context-aware query failure' prediction approach uses a combination of 'user indicators' and 'engine indicators' to predict whether a particular query is likely to fail in the context of a particular search session. User indicators are derived from the search log and capture the patterns of query (re)formulation behavior and the click-through data of a user during a typical video search session. Engine indicators are derived from the video search results list and capture the visual variance of search results that would be offered to the user for the given query. We validate our approach experimentally on a test set containing 1+ million video search queries and show its effectiveness compared to a set of conventional QPP baselines. Our approach achieves a 13% relative improvement over the baseline.

Cross language information retrieval (CLIR) is a retrieval process in which the user fires queries in one language to retrieve information from another (different) language. The diversity of information and language barriers are the serious issues for communication and cultural exchange across the world. To solve such barriers, Cross language information retrieval system, are nowadays in strong demand. CLIR is a subset of Information Retrieval (IR) system. Information Retrieval deals with finding useful information from a large collection of unstructured, structured and semi-structured data to a user query where the query is a set of keywords. Information Retrieval can be classified into different classes such as Monolingual information retrieval, Bi-Lingual Information Retrieval, Multilingual information retrieval and Cross language information retrieval. This paper focuses on the various IR variants and techniques used in CLIR system. Further, based on available literature, a number of challenges and issues in CLIR have been identified and discussed. It gives an overview of the advantages, limitations, tools available in CLIR research. It also describes new application areas of CLIR such as medical, multimedia, question answering system etc. The need for exploring and building more specialized information system that enable speakers of an Odia language to discover valuable information beyond linguistic and cultural barriers. This study is aimed at building an experimental CLIR system between one of the under-resourced language (i.e. Odia) and one of the most commonly used online language (i.e. English) in future.

Now finding relevant information is absolutely needed by users of the information. Actually, finding relevant information is more difficult than just looking for information. The presence information retrieval (IR) system is a system for automatically searching the relevant information to the user needs, which is expressed in the required query, and this query will be used as an input and processed by IR system and then will get relevant documents to the required query. One of methods of finding relevant information by query is term weighting by both query and document. The commonly used methods are the term weighting of local and global weighting, while the local term weighting algorithms that are used such as TF, TF logarithmic, binary TF and augmented TF and global weighting is IDF, IDFP, IDFB. In this research, besides of comparison of term weighting algorithms, it is also proposed new improvement in term weighting algorithms by adding global weight value that changes base 10 logarithmic to base 2 logarithmic and adds the number 1 in the global term weighting IDFP. Measurements result of this research are Precision, Recall and NIAP. In This research, the best result for precision and NAIP have been performed by new propose term weighting algorithms. After compare and analyze the result of the weighting algorithms. It is necessary to combine the weighting with semantic algorithms so that it will get better result.

Evaluation is crucial in assessing the effectiveness of new information retrieval and human computer interaction techniques and systems. Relevance judgements are often performed by humans, which makes obtaining them expensive and time consuming. Consequently, relevance judgements are usually performed only on a subset of a given collection of data or experimental results with a focus on the top ranked documents. However, when assessing the performance of exploratory search systems, the diversity or subjective relevance of documents that the user was presented with over a search session are often of more importance than the relative ranking of top documents. In order to perform these types of assessment, all the documents in a given collection need to be judged for relevance. In this paper, we propose an approach based on topic modeling that can greatly accelerate document relevance judgment of an entire document collection with an expert assessor needing to mark only a small subset of documents from a given collection. Experimental results show a substantial overlap between relevance judgments compared to a human assessor.

Difficulties with Web based full text information retrieval (IR) systems include spurious matches, manually intensive document sifting, and the absence of communication or coordination between users. To address these difficulties, we introduce the Annotate! system which enables document annotations, and captures global usage history. Annotate! provides improved data and metadata clues to guide the user in a search session. Two data sets, declared in XML, are at the core of Annotate!: discussion data, a composite of documents and user annotations and session data which captures user timings at the various interface layers. We discuss a prototype implementation, and show that the collaborative infrastructure enabled by Annotate! can be predicted to improve the diffusion of ideas in the search community.

Ranking is likely the most important process of an information retrieval (IR) system that will be used to evaluate and measure the effectiveness of an IR system. This paper aims to produce the implementation of fuzzy logic controller of Mamdani-type fuzzy inference system for defining the ranking function by using the BM25 model in the Malay IR system that also includes the Malay Stemmer. The result of the ranking function then will be compared to the result of vector space model that is also applied in Malay IR system and be evaluated using relevant document by the hadith expert. The results showed that FBMIR has slightly outperformed vector space model on three topic set of query results such as 'Iman', 'Ilmu' and 'Wuduk' on the precision at rank 10 and the percentage of no relevant document in the top ten retrieved measures.

To properly handle concurrent accesses to documents by updates and queries in information retrieval (IR) systems, efforts are on to integrate IR features with database management system (DBMS) features. However, initial research has revealed that DBMS features optimized for traditional databases, display degraded performance while handling text databases. Since efficiency is critical in IR systems, infrastructural extensions are necessary for several DBMS features, transaction support being one of them. This paper focuses on developing efficient transaction support for IR systems where updates and queries arrive $dynamically$, by exploiting the data characteristics of the indexes as well as of the queries and updates that access the indexes. Results of performance tests on a prototype system demonstrate the superior performance of our algorithms.