物件導向軟體之架構(Object-Oriented Software Construction)探討

National Institute of Standards and Technology における超伝導研究及び生活

An overview of vertical handover decision strategies in heterogeneous wireless networks

An orchestrated survey of methodologies for automated software test case generation

In e-commerce and mobile commerce, personalization has been recognized as an important approach element in customer relationships and Web strategies. However, there are wide differences in how this concept is defined, characterized, and implemented in the literature. In this article we present a high-level framework for classifying approaches to personalization that delineates fundamental assumptions about personalization in the literature and relates them to strategies for developing personalization systems. The framework consists of 2 parts: (a) a set of perspectives on personalization that guide the design of personalization systems at a general level and (b) a scheme for classifying how personalization can be implemented. The personalization perspectives represent 4 distinct schools of thought on the nature of personalization distilled from the literature of several fields. These perspectives are ideal types and we discuss them in terms of the motivation they supply for personalization, the goals and ...

What Is Personalization? Perspectives on the Design and Implementation of Personalization in Information Systems

To implement seamless mobility inside an integrated, multiple (e.g. GPRS/WiFi) access system, a vertical handover policy has to be devised. This is usually done at the mobile terminal, allowing it to be customized from a end-user perspective, in order to fit individual needs/preferences. We propose a new approach in taking vertical handover decisions, which are not anymore exclusively based on the knowledge of the available access networks' characteristics but also on higher level parameters which fall in the transport and application layers. To this extent, in this paper a model has been realized and simulations have been run in order to evaluate the impact of the vertical handover and its frequency on a set of typical user's network applications/services. We also take into account the user preferences in terms of cost and quality of service. We believe this approach reflects the optimal settings from the user's point of view with regard to his running services and applications. Our aim is to understand how to define a metric to be used in order to devise a solution which should try to balance the overall cost of vertical handovers with the actual benefits they bring to actual user's networking needs. This way, each mobile user could autonomously apply the handover decision policy which is more convenient to his specific needs.

A user-centric analysis of vertical handovers

Usage of combinatorial testing is wide spreading as an effective technique to reveal unintended feature interaction inside a given system. To this aim, test cases are constructed by combining tuples of assignments of the different input parameters, based on some effective combinatorial strategy. The most commonly used strategy is two-way (pairwise) coverage, requiring all combinations of valid assignments for all possible pairs of input parameters to be covered by at least one test case. In this paper a new heuristic strategy developed for the construction of pairwise covering test suites is presented, featuring a new approach to support expressive constraining over the input domain. Moreover, it allows the inclusion or exclusion of ad-hoc combinations of parameter bindings to let the user customize the test suite outcome. Our approach is tightly integrated with formal logic, since it uses test predicates to formalize combinatorial testing as a logic problem, and applies an external model checker tool to solve it. The proposed approach is supported by a prototype tool implementation, and early results of experimental assessment are also presented.

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A logic-based approach to combinatorial testing with constraints

The combination of personal computing devices and wireless ad-hoc networks allows the concept of mobile ad-hoc information system, consisting of a highly dynamic, decentralized and self-organizing network of autonomous and mobile devices that interact as peers [M. Hannicainen et al. (2002), L. Kleinrock, (2000)]. Here we define a middleware layer, named Expeerience. We have decided to adopt as a basic software framework, an emerging P2P open technology such as JXTA. The second issue we address in this work is the integration of some code mobility support in the developed middleware to allow the distribution and execution of services on peers that originally do not own the service code. This has been introduced in our platform by adding a mobile code service, which enables to download and install new services dynamically only if necessary.

Expeerience: a JXTA middleware for mobile ad-hoc networks

Veri?cation and validation of highly-con?gurable software systems, such as those supporting many optional or customizable features, is a challenging activity. In fact, due to its intrinsic complexity, formal modeling of the whole system may require a great effort. Modeling activities may become extremely expensive and time consuming, and the tester may decide to model (at least initially) only the inputs and require they are suf?ciently covered by tests. The recent wide spreading usage of combinatorial interaction testing (CIT) is dramatically improving the effectiveness of this activity. Although there exist analytical ways to derive minimal sized CIT test suites, they are not applicable to all task sizes. Therefore, researchers have explored many techniques based on greedy or heuristic algorithms that may lead to sub-optimal result in the size of the built test suite but that are applicable to problems of real size. In this paper, a new parameter-based heuristic algorithm for the construction of pairwise covering test suites is presented; it is based on a symmetry property of covering arrays and it is called IPOS . Time and space complexity of IPOS is discussed in comparison especially with the only other parameter-based approach existing in literature. The proposed approach is supported by a prototype implementation, and experimental assessment is also presented.

/pdf/ipo-s-incremental-generation-of-combinatorial-interaction-2eljgy37ok.pdf

IPO-s: Incremental Generation of Combinatorial Interaction Test Data Based on Symmetries of Covering Arrays

Combinatorial testing is as an effective testing technique to reveal failures in a given system, based on input combinations coverage and combinatorial optimization. Combinatorial testing of strength t (t???2) requires that each t-wise tuple of values of the different system input parameters is covered by at least one test case. Combinatorial test suite generation algorithms aim at producing a test suite covering all the required tuples in a small (possibly minimal) number of test cases, in order to reduce the cost of testing. The most used combinatorial technique is the pairwise testing (t?=?2) which requires coverage of all pairs of input values. Constrained combinatorial testing takes also into account constraints over the system parameters, for instance forbidden tuples of inputs, modeling invalid or not realizable input values combinations. In this paper a new approach to combinatorial testing, tightly integrated with formal logic, is presented. In this approach, test predicates are used to formalize combinatorial testing as a logical problem, and an external formal logic tool is applied to solve it. Constraints over the input domain are expressed as logical predicates too, and effectively handled by the same tool. Moreover, inclusion or exclusion of select tuples is supported, allowing the user to customize the test suite layout. The proposed approach is supported by a prototype tool implementation and results of experimental assessment are also presented.

/pdf/a-formal-logic-approach-to-constrained-combinatorial-testing-26o506ldr9.pdf

Andrea Calvagna

Papers

A user-centric analysis of vertical handovers

A logic-based approach to combinatorial testing with constraints

Expeerience: a JXTA middleware for mobile ad-hoc networks

IPO-s: Incremental Generation of Combinatorial Interaction Test Data Based on Symmetries of Covering Arrays

A Formal Logic Approach to Constrained Combinatorial Testing