| 1. |
- Ågren, Ola, 1968-
(författare)
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Finding, extracting and exploiting structure in text and hypertext
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Data mining is a fast-developing field of study, using computations to either predict or describe large amounts of data. The increase in data produced each year goes hand in hand with this, requiring algorithms that are more and more efficient in order to find interesting information within a given time. In this thesis, we study methods for extracting information from semi-structured data, for finding structure within large sets of discrete data, and to efficiently rank web pages in a topic-sensitive way. The information extraction research focuses on support for keeping both documentation and source code up to date at the same time. Our approach to this problem is to embed parts of the documentation within strategic comments of the source code and then extracting them by using a specific tool. The structures that our structure mining algorithms are able to find among crisp data (such as keywords) is in the form of subsumptions, i.e. one keyword is a more general form of the other. We can use these subsumptions to build larger structures in the form of hierarchies or lattices, since subsumptions are transitive. Our tool has been used mainly as input to data mining systems and for visualisation of data-sets. The main part of the research has been on ranking web pages in a such a way that both the link structure between pages and also the content of each page matters. We have created a number of algorithms and compared them to other algorithms in use today. Our focus in these comparisons have been on convergence rate, algorithm stability and how relevant the answer sets from the algorithms are according to real-world users. The research has focused on the development of efficient algorithms for gathering and handling large data-sets of discrete and textual data. A proposed system of tools is described, all operating on a common database containing "fingerprints" and meta-data about items. This data could be searched by various algorithms to increase its usefulness or to find the real data more efficiently. All of the methods described handle data in a crisp manner, i.e. a word or a hyper-link either is or is not a part of a record or web page. This means that we can model their existence in a very efficient way. The methods and algorithms that we describe all make use of this fact.
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| 2. |
- Eriksson, Magnus, 1976-
(författare)
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Engineering Families of Software-Intensive Systems using Features, Goals and Scenarios
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the last decade, software has become an integral part of many products with which it is not traditionally associated (e.g., automobiles, medical equipment, home appliances, etc.). This has led to problems in many organizations, since it has proved difficult to integrate software engineering processes with other engineering processes. To address the increased complexity and to coordinate their engineering efforts, many organizations working in such domains have therefore introduced systems engineering into their business processes. Systems engineering is an interdisciplinary approach to system development. Teamwork is essential in developing complex systems, and systems engineering orchestrates this process throughout the lifespan of a system. The focus of systems engineering is on defining customer needs and required functionality, documenting requirements, synthesizing a design and validating the system. A problem with the traditional techniques of systems engineering is, however, that they provide inadequate support for achieving high levels of reuse between different projects. In this dissertation, methods and tools with the overall purpose of providing an improved reuse infrastructure for systems engineering artifacts and their resulting detailed design artifacts are proposed. The proposed methods and tools are based on the software product-line approach, a reuse strategy which focuses on families of related systems that address particular market segments. Studies have shown that if an empirical study does not report experiences from that which practitioners consider a “real” situation, results are likely to be ignored. Even though case studies cannot achieve the scientific rigor of formal experiments, case studies can provide enough information to decide if a specific technology will benefit a particular organization. To ensure industry-relevant research results, case studies on real development projects were chosen as the main vehicle for performing research. This dissertation reports experiences from four empirical studies which were performed within the Swedish defense industry. The studies indicate that the proposed methods and tools indeed provide an improved reuse infrastructure, compared to the previously used methods and tools.
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| 3. |
- Loconsole, Annabella, 1965-
(författare)
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Definition and validation of requirements management measures
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The quality of software systems depends on early activities in the software development process, of which the management of requirements is one. When requirements are not managed well, a project can fail or become more costly than intended, and the quality of the software developed can decrease. Among the requirements management practices, it is particularly important to quantify and predict requirements volatility, i.e., how much the requirements are likely to change over time. Software measures can help in quantifying and predicting requirements attributes like volatility. However, few measures have yet been defined, due to the fact that the early phases are hard to formalise. Furthermore, very few requirements measures have been validated, which would be needed in order to demonstrate that they are useful. The approach to requirements management in this thesis is quantitative, i.e. to monitor the requirements management activities and requirements volatility through software measurement. In this thesis, a set of 45 requirements management measures is presented. The measures were defined using the goal question metrics framework for the two predefined goals of the requirements management key process area of the capability maturity model for software. A subset of these measures was validated theoretically and empirically in four case studies. Furthermore, an analysis of validated measures in the literature was performed, showing that there is a lack of validated process, project, and requirements measures in software engineering. The studies presented in this thesis show that size measures are good estimators of requirements volatility. The important result is that size is relevant: increasing the size of a requirements document implies that the number of changes to requirements increases as well. Furthermore, subjective estimations of volatility were found to be inaccurate assessors of requirements volatility. These results suggest that practitioners should complement the subjective estimations for assessing volatility with the objective ones. Requirements engineers and project managers will benefit from the research presented in this thesis because the measures defined, proved to be predictors of volatility, can help in understanding how much requirements will change. By deploying the measures, the practitioners would be prepared for possible changes in the schedule and cost of a project, giving them the possibility of creating alternative plans, new cost estimates, and new software development schedules.
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| 4. |
- Nordström, Marie, 1959-
(författare)
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He[d]uristics - Heuristics for designing object oriented examples for novices
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of examples is known to be important in learning, they should be “exemplary” and function as role-models. Teaching and learning problem solving and programming in the object oriented paradigm is recognised as difficult. Object orientation is designed to handle complexity and large systems, and not with education in focus. The fact that object orientation often is used as first paradigm makes the design of examples even more difficult and important. In this thesis, a survey of the literature is made to establish a set of characteristics for object orientation in general. This set of characteristics is then applied to the educational setting of introducing novices to object oriented problem solving and programming, resulting in a number of heuristics for educational purposes, called He[d]uristics. The proposed He[d]uristics are targeted towards educators designing small-scale examples for novices, and is an attempt to provide help in designing suitable examples, not a catalogue of good ones. The He[d]uristics are discussed and exemplified and also evaluated versus the derived set of characteristics and known common problems experienced by novices.
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