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Models and criteria of evaluation of electronic resources collections

Posted in PhD Theses

Title: Models and criteria of evaluation of electronic resources collections
Creator: Tsakonas Giannis
Date: 2009
Abstract: Digital libraries consist of an important part of the electronic source that cover the constantly escalating information needs of users from different served communities. They constitute a reference point in the contemporary information world, since the investments in economic level are high, either in the development section, or in the acquisition of access to the provided information. As information systems digital libraries feature complex phases of development and in this context evaluation is judged as a significant element of improvement and adaptation. The user-centered conceptions of evaluation have gained ground during the late years bridging the gap with the system-centered approaches. These user-centered conceptions, not only place in the epicentre of the improvements the benefits of the user for the enhancement of his interaction with these systems, but are informed by his properties, so this information and intervention in the operation of digital libraries will be substantial. In the present doctoral dissertation thesis the endeavour of development of a user-centered model of evaluation of digital libraries is presented. By starting from the need for covering many different objects which are dictated by the multi-disciplinarily of the field, the complexity of both the systems and the context, and its development of the users’ properties, this model presents features of suppleness, ampleness and utilization of users’ characteristics. In the centre of it there is the interaction between three main agents, namely the content, the system and the user. These interactions are based on axes that describe the attributes of usefulness, usability and performance. Through two pilot studies it is attempted to apply this model and to validate both general and specific hypotheses. A central question that is researched through this thesis and which is to be answered with clarity is whether digital library interaction is a consequence of the correlation between content usefulness and system usability. A more specific question concerns the research of the importance of the attributes that constitute usefulness and usability in the creation of a satisfactory interaction. The results of this thesis include (a) the formal description (by means of mathematic logic) of the process of evaluation in the context of digital libraries, but also of the specific expression of interaction in digital libraries, (b) the composition of the model, as well the proposition of the main attributes of usefulness, usability and performance, (c) the conclusions that have been sprung from the application of the model in the experimental evaluations, and (d) the formal description of assessment of an evaluation model.
Source: (in Greek)

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A Study on Design Parameters for Ubiquitous Computing Systems to Develop and Evaluate Services in Hybrid Information Environments

Posted in PhD Theses

Author: Veronikis, Spyros
Publication year: 2010

Abstract: The typical goals of a user in a hybrid information environment like a library is the information retrieval which is achieved by mainly two techniques; searching and browsing. These two techniques can be expressed in several ways and they are supported by different technological and human resources. For example, a library visitor may ask a librarian for a certain group of books (e.g. psychology) or walk among the stacks to locate it. Similarly, he may submit a query in the electronic OPAC or browse the indices and digital collections of the library. So far, the technological equipment for these processes is restricted into desktop terminals, which aren't portable. As a result, browsing among the information objects of physical and digital domains is not performed in seamless manner.

As part of this project, I’m studying the use of handheld devices which allow the unification of access to the two information domains. An information environment like a library which usually offers both kind of services, could benefit from the technologies of mobile computing and wireless networks, offering new services that help its patrons to retrieve and manage the information of their interest, coming from diverse domains, each with its own benefits.

My dissertation thesis focuses on two weave research objects; part of the first is the design process of a model for the integration of digital and conventional libraries and the services which hybrid libraries may offer. In other words, it involves gathering, studying and analyzing all the necessary information and parameters which lead to the development of a prototype model. The second part of the thesis focuses on determining the evaluation methods, criteria and parameters to assess our model. The evaluation results will be used to redesign our model. Through this iterative process we expect to come up with a model which is more representative of the real world situation and which continuously adapts to this changing situation over time.

 

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Optimization procedures for the interoperability of Z39.50 distributed information systems and bibliographic metadata integration

Posted in PhD Theses

Title: Optimization procedures for the interoperability of Z39.50 distributed information systems and bibliographic metadata integration

Creator: Sfakakis, Michalis

Abstract: The significant number of available information sources in conjunction with the different access methods led to the development of ‘one-stop’ search interfaces. An implementation of such search interfaces is meta-search engines, also known as federated search, broadcast search, virtual union catalogues, etc. Meta-search engines help users access uniformly a great number of distributed and autonomous information sources. Most of these information sources are hidden behind query interfaces without any access to the underlying data structures and query methods. In some cases query methods for the underlying sources share common characteristics or conform to a standard information retrieval protocol. This is mostly the case when metadata describe materials from a common information community.

Meta-search challenges refer to performance, source availability and interoperability. Interoperability decides the fate of the meta-search engine regarding effective querying of the sources and integration of the results. One significant task affecting the effectiveness of the meta-search engine is its ability to transform the user’s query into every underlying source’s query system. Moreover, within the library community, many information sources publicize their metadata with query interfaces based on the concept of the abstract Access Point and mainly conforming to the Z39.50 information retrieval protocol. The varying or poor implementations of the protocol restrict the query interfaces to a relatively small number of available Access Points. Unsupported Access Points are very common, especially when searches are addressed to more than one source. When a query contains an unsupported Access Point the query either fails or generates an inconsistent answer if the source substitutes the unsupported Access Point with a supported one.

The aim of this thesis is to develop methods to improve the effectiveness of the meta-search engines in the context of digital libraries. The proposed methods, based on key characteristics of the communication protocols and the metadata used by the information sources, were designed to indirectly achieve better functional and semantic interoperability. Due to the universal use of Z39.50 protocol in the library community particular emphasis is placed on it as a key regulator of effectiveness and efficiency in the development of the meta-search engines.

The main directions of research and the contribution of the thesis concern (a) the methods for the query broadcast to the sources, as well as the asynchronous and gradual retrieval and process of the retrieved results, (b) the description of the supported search characteristics of the source and the appropriate rewriting of the user query to supported queries by the source. In case where a source does not support a query, the query is rewritten either to another supported query, or a set of supported queries, with equivalent semantics, if it is possible, or the recall and the precision of the rewritten queries to fulfill predefined user preferences. Query rewritings are based on the Semantic Access Point Network (SAPN), which is an auto-generated semantic graph from metadata semantics in RDFS language, and (c) the process of the query results and the composition of work entity clusters according to the FRBR conceptual model.

Sfakakis_PhD.pdf

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Access and availability policies of libraries' digital content

Posted in PhD Theses

Title: Access and availability policies of libraries' digital content
Creator: Koulouris, Alexandros
Date: 2007
Abstract: In this Ph.D. thesis, the access and availability policies (policies from now on) of libraries' digital content are examined in relation to specific factors, which according to bibliography, affect them. The factors refer to acquisition method, intellectual property, content type, digital content creation type and library type. The intellectual property and policies relation is examined in different countries worldwide. The electronic theses and dissertations, is the case study selected for analyzing the relation of policies and content type. Alternative access policies for such content are proposed. The national and academic libraries worldwide, is the core for the policies and library type's relation analysis. The questionnaire, the personal observation and the study of the relevant literature are the methods used for collecting the research data. Generalized rules in relation to the factors are extracted for the libraries' followed policy practices. The absence of an appropriate model for national and academic libraries' digital content is ascertained. Two flexible access and reproduction policy models for national and academic libraries' digital content are proposed. The models contain simplified policy rules, resulted from libraries' common policy practices, supplemented by alternative policy proposals. Each model results in a decision tree, which proposes alterative and flexible access and reproduction policy routes according to the factors, digital content creation type, acquisition method and intellectual property that apply on each case. The proposing policy models and the decision trees that result in, hope to be helpful in resolving the policy problem. Additionally, they may constitute useful tools (guides) in forming the policies and managing the national and academic libraries' digital information (content).
Source: koulouris_policies.pdf (in Greek)