Solving the Uncapacitated Single Allocation p-Hub Median Problem on GPU

A parallel genetic algorithm (GA) implemented on GPU clusters is proposed to solve the Uncapacitated Single Allocation p-Hub Median problem. The GA uses binary and integer encoding and genetic operators adapted to this problem. Our GA is improved by generated initial solution with hubs located at middle nodes. The obtained experimental results are compared with the best known solutions on all benchmarks on instances up to 1000 nodes. Furthermore, we solve our own randomly generated instances up to 6000 nodes. Our approach outperforms most well-known heuristics in terms of solution quality and time execution and it allows hitherto unsolved problems to be solved

Managing facility disruption in hub-and-spoke networks: formulations and efficient solution methods

Hub disruption result in substantially higher transportation cost and customer dissatisfaction. In this study, first a mathematical model to design hub-and-spoke networks under hub failure is presented. For a fast and inexpensive recovery, the proposed model constructs networks in which every single demand point will have a backup hub to be served from in case of disruption. The problem is formulated as a mixed integer quadratic program in a way that could be linearized without significantly increasing the number of variables. To further ease the model’ computational burden, indicator constraints are employed in the linearized model. The resulting formulation produced optimal solutions for small and some medium size instances. To tackle large problems, three efficient particle swarm optimisation-based metaheuristics which incorporate efficient solution representation, short-term memory and special crossover operator are proposed. We present the results for two scenarios relating to high and low probabilities of hub failures and provide managerial insight. The computational results, using problem instances with various sizes taken from CAB and TR datasets, confirm the effectiveness and efficiency of the proposed problem formulation and our new solution techniques

A Multi-Pronged Approach to Test the Usability of SAP R/3

Part of a collection of essays on enterprise resources (ERP) and networking presented at the 2005 SAP University Alliances Curriculum Congress, held at the Kelley School of Business, Indiana University, Bloomington, Indiana

A Balanced Usability Checklist Approach to Evaluate Palestinian Hotel Websites

This paper introduces a Balanced Usability Checklist (BUC) approach to assess the usability of ten Palestinian hotel websites. The BUC is a modified version of the known checklist analysis technique of user interfaces and includes dimensions for User Friendliness, Attractiveness, Marketing Effectiveness, and Technical Aspects of a website. Eight participants with experience in website design and usability were asked to evaluate each of the ten websites using the BUC approach. Overall, the hotel websites faired [sic] poorly on three out of the four dimensions. A relative ranking, based on the total score, was used to rank the hotels from 1 (highest) to 10 (lowest). This study has numerous implications, mainly for hotel managers wanting to improve the delivery of their services on the Internet. Results, limitations, and future research are discussed

Using the Analytic Hierarchical Process to Create a Single Usability Score for Website Interfaces

We propose a new approach to create a single score metric to compare and rank the usability of website interfaces. The approach is based on the Analytic Hierarchy Process. We built the model and validated it using four usability studies, two of which are on a manufacturing firm website and the other two are on a service firm website. The results revealed a difference in domain between manufacturing and service. Still, this approach to creating a single score for usability is new in the literature for website evaluation and can help explain the ranking of website interfaces to non-experts. This is especially true for clients with the need to repeat website evaluations yearly or with clients who need a comparative analysis for their website against others in the same business. Future research is necessary to develop this approach further and validate it using a more comprehensive data set from an identical domain

Using the End-User Computing Satisfaction (EUCS) Instrument to Measure Satisfaction With a Web Site

The purpose of this study is to revise and revalidate the End‐User Computing Satisfaction (EUCS) instrument to measure satisfaction with a Web site from a usability perspective. This study is especially important given the increased significance of the Web and the uniqueness of the Web as a computing environment. A total of 176 students participated in a lab simulation that involved a usability evaluation of the Lands\u27 End Web site (http://www.landsend.com). Students were asked to complete a set of tasks, record their answers, and then complete the EUCS instrument. Confirmatory factor analysis and invariance analyses were conducted to test the reliability, validity, and generalizability of the revised EUCS. The results show that the EUCS is a valid and robust instrument in the Web environment but that one of the subfactors, timeliness, will need further refinement in the future. Usability practitioners can use the EUCS to measure end‐user satisfaction with a Web site and use the feedback for improving Web‐site design. We describe a case study of an actual usability application that utilized the revised EUCS effectively to support the design of building supply Web sites involving two types of end users, homeowners and contractors. We also propose a typology that researchers can use as a starting point to judge when it is necessary to revalidate an instrument like the EUCS. Finally, we discuss the limitations of our study and present avenues for future research