The Experts below are selected from a list of 47988 Experts worldwide ranked by ideXlab platform
Margaret Burnett - One of the best experts on this subject based on the ideXlab platform.
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hci research regarding end User Requirement specification a tutorial
Knowledge Based Systems, 2003Co-Authors: Margaret BurnettAbstract:Can end Users someday enter their Requirements directly into program generation tools? This paper surveys literature that sheds some light upon this question, highlighting devices from HCI research that can be used to help in accomplishing this goal.
Joarder Kamruzzaman - One of the best experts on this subject based on the ideXlab platform.
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reputation and User Requirement based price modeling for dynamic spectrum access
IEEE Transactions on Mobile Computing, 2014Co-Authors: Rakib Hassan, Gour Karmakar, Joarder KamruzzamanAbstract:Secondary service providers can buy spectrum resources from primary service providers for a short or long period of time and exploit it to solve the problem of spectrum scarcity. This buying decision of spectrum buyers can depend on several factors including pricing of the spectrum, reputation of a seller, and duration of the contract and spectrum quality. However, existing pricing models for dynamic spectrum access consider mainly bandwidth which makes them unsuitable for real-world trading. In this paper, we consider these issues related to the pricing of spectrum sale in terms of microeconomic theories. First, we consider reputation of spectrum sellers and update it dynamically by considering a buyer’s own trading experience with the sellers and collecting recommendations on sellers from other buyers. Second, trustworthiness of recommenders as well as incentive to encourage recommendations are modeled. Third, contract duration and spectrum quality are incorporated such that a buyer’s utility is formulated as a function of buyer’s resource Requirement, reputation of seller and trustworthiness of recommenders. Fourth, the model is analyzed using dynamic pricing of the market and the solution is obtained using market equilibrium. Results demonstrate the superiority of our model over the existing microeconomic models for dynamic spectrum trading.
Shamik Sural - One of the best experts on this subject based on the ideXlab platform.
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minimizing organizational User Requirement while meeting security constraints
ACM Transactions on Management Information Systems, 2015Co-Authors: Shamik Sural, A K Majumdar, Jaideep Vaidya, Vijayalakshmi AtluriAbstract:Large systems are complex and typically need automatic configuration to be managed effectively. In any organization, numerous tasks have to be carried out by employees. However, due to security needs, it is not feasible to directly assign any existing task to the first available employee. In order to meet many additional security Requirements, constraints such as separation of duty, cardinality and binding have to be taken into consideration. Meeting these Requirements imposes extra burden on organizations, which, however, is unavoidable in order to ensure security. While a trivial way of ensuring security is to assign each User to a single task, business organizations would typically like to minimize their costs and keep staffing Requirements to a minimum. To meet these contradictory goals, we define the problem of Cardinality Constrained-Mutually Exclusive Task Minimum User Problem (CMUP), which aims to find the minimum Users that can carry out a set of tasks while satisfying the given security constraints. We show that the CMUP problem is equivalent to a constrained version of the weak chromatic number problem in hypergraphs, which is NP-hard. We, therefore, propose a greedy solution. Our experimental evaluation shows that the proposed algorithm is both efficient and effective.
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impact of multiple t t smer constraints on minimum User Requirement in rbac
International Conference on Information Systems Security, 2014Co-Authors: Shamik Sural, A K MajumdarAbstract:Separation of Duty (SoD) constraints are widely used to specify Role Based Access Control (RBAC) policies in commercial applications. It has been shown previously that efficient implementation of SoD policies in RBAC can be done using t-t Statically Mutually Exclusive Roles (SMER) constraints. In this paper, we present a method for finding the minimum number of Users required under multiple t-t SMER constraints. The problem is shown to be NP-complete. We model the general problem using graphs, and present a two-step method for solving it. In the first step, a greedy algorithm is proposed that selects a graph which is likely to have the minimum chromatic number out of a set of graphs. The second step uses a known chromatic number finding algorithm for determining the chromatic number of the graph selected in the first step. Results for different values of the number of roles and the number of constraints as well as for different values of t have been reported.
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minimum User Requirement in role based access control with separation of duty constraints
Intelligent Systems Design and Applications, 2012Co-Authors: Shamik Sural, A K MajumdarAbstract:Constraints, specifically Separation of Duty (SoD) constraints, constitute an essential component for specifying Role Based Access Control (RBAC) policies. While it has been shown earlier that SoD constraints can be effectively represented using a set of t - t Statically Mutually Exclusive Roles (SMER) constraints, this paper presents a method for finding minimum number of Users under multiple SMER constraints. We show that one way of solving the problem is to evaluate chromatic numbers for a set of graphs. However, since exhaustive search is computationally quite expensive, we present a genetic algorithm formulation of the problem. Each chromosome is a string of positive integers within a certain range and its length equals the number of t-t SMER constraints in the system. We report our results for different values of the number of roles and the number of constraints and also for different values of t.
A K Majumdar - One of the best experts on this subject based on the ideXlab platform.
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minimizing organizational User Requirement while meeting security constraints
ACM Transactions on Management Information Systems, 2015Co-Authors: Shamik Sural, A K Majumdar, Jaideep Vaidya, Vijayalakshmi AtluriAbstract:Large systems are complex and typically need automatic configuration to be managed effectively. In any organization, numerous tasks have to be carried out by employees. However, due to security needs, it is not feasible to directly assign any existing task to the first available employee. In order to meet many additional security Requirements, constraints such as separation of duty, cardinality and binding have to be taken into consideration. Meeting these Requirements imposes extra burden on organizations, which, however, is unavoidable in order to ensure security. While a trivial way of ensuring security is to assign each User to a single task, business organizations would typically like to minimize their costs and keep staffing Requirements to a minimum. To meet these contradictory goals, we define the problem of Cardinality Constrained-Mutually Exclusive Task Minimum User Problem (CMUP), which aims to find the minimum Users that can carry out a set of tasks while satisfying the given security constraints. We show that the CMUP problem is equivalent to a constrained version of the weak chromatic number problem in hypergraphs, which is NP-hard. We, therefore, propose a greedy solution. Our experimental evaluation shows that the proposed algorithm is both efficient and effective.
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impact of multiple t t smer constraints on minimum User Requirement in rbac
International Conference on Information Systems Security, 2014Co-Authors: Shamik Sural, A K MajumdarAbstract:Separation of Duty (SoD) constraints are widely used to specify Role Based Access Control (RBAC) policies in commercial applications. It has been shown previously that efficient implementation of SoD policies in RBAC can be done using t-t Statically Mutually Exclusive Roles (SMER) constraints. In this paper, we present a method for finding the minimum number of Users required under multiple t-t SMER constraints. The problem is shown to be NP-complete. We model the general problem using graphs, and present a two-step method for solving it. In the first step, a greedy algorithm is proposed that selects a graph which is likely to have the minimum chromatic number out of a set of graphs. The second step uses a known chromatic number finding algorithm for determining the chromatic number of the graph selected in the first step. Results for different values of the number of roles and the number of constraints as well as for different values of t have been reported.
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minimum User Requirement in role based access control with separation of duty constraints
Intelligent Systems Design and Applications, 2012Co-Authors: Shamik Sural, A K MajumdarAbstract:Constraints, specifically Separation of Duty (SoD) constraints, constitute an essential component for specifying Role Based Access Control (RBAC) policies. While it has been shown earlier that SoD constraints can be effectively represented using a set of t - t Statically Mutually Exclusive Roles (SMER) constraints, this paper presents a method for finding minimum number of Users under multiple SMER constraints. We show that one way of solving the problem is to evaluate chromatic numbers for a set of graphs. However, since exhaustive search is computationally quite expensive, we present a genetic algorithm formulation of the problem. Each chromosome is a string of positive integers within a certain range and its length equals the number of t-t SMER constraints in the system. We report our results for different values of the number of roles and the number of constraints and also for different values of t.
Manfred Tscheligi - One of the best experts on this subject based on the ideXlab platform.
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designing accessible experiences for older Users User Requirement analysis for a railway ticketing portal
Universal Access in The Information Society, 2011Co-Authors: Ozge Subasi, Michael Leitner, Norman Hoeller, Arjan Geven, Manfred TscheligiAbstract:This article presents the results of a survey that shows that older Users differ in their attitude and experience towards the Internet not only according to their age or to their previous knowledge with Internet services, but also according to what they are expecting from this media. The aim of this study was to collect information about barriers on usage and perception of an online ticketing service for a nationwide public railway company, in order to enhance the notion of “accessibility” toward a broader understanding including non-technical accessibility factors as semantic accessibility and/or procedural accessibility. The results of the survey with 1,208 participants and additionally focus groups, interviews and qualitative analysis of User feedback indicate that in order to improve and optimize the usage of the online system for older adults, it is necessary to develop a system which is not only universally accessible, but also satisfies the specific expectations of senior Users. This article concentrates on designing accessible User experiences and presents several recommendations to the area and for WCAG 2.0 according to the results.
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User Requirement analysis for a railway ticketing portal with emphasis on semantic accessibility for older Users
Proceedings of the 2009 International Cross-Disciplinary Conference on Web Accessibililty (W4A), 2009Co-Authors: Michael Leitner, Ozge Subasi, Arjan Geven, Norman Holler, Manfred TscheligiAbstract:In this paper, we present the results from a survey on User Requirements for older Users of online ticketing services of a nationwide railway ticket and travel information portal. Our survey shows that older Users differentiate in their attitude towards internet according to their experience with internet services and the service provided, not only according to their age. Further, our study indicates that in contrary to common belief advertisement or interactive elements are not perceived as negative all the time. The results of a questionnaire with 1200 responses, focus groups, interviews and qualitative analysis of User feedback also indicate that in order to improve and optimize the usage of the online system for older adults, it is needed to supply the system not only with technical accessibility Requirements but also with an understanding of universal accessibility Requirements. Universal Requirements are defined by real User and usage cases and they consider standardization on not only coding but also predictability of usage and same patterns of interaction for similar websites.
