Using linear programming to simulate service engineers

This paper describes the use of a network flow model to simulate a proposed spatial allocation of engineers to service requests. The model involves generating a pattern of demand and then determining an allocation of engineers to jobs which maximises the number of jobs immediately serviced. Within the maximum number of jobs the allocation pattern which minimises the amount of travelling is determined. The results obtained were compared with the allocation rules then in use.     

Death of an OR group

As part of a major investigation into the success and survival of OR groups in the UK, the closure of a long standing OR group in an organisation in the energy sector was examined. Several members of the organization and the OR group were interviewed about the closure and the quality of the OR service, confirming that the Group had many satisfied clients. The factors influencing the closure were related to a set of previously identified success factors. External and organizational factors were the main influences on the closure decision but some weaknesses in the management of the group were observed. Following the closure, several members of the Group were redeployed, but two years afterwards only one remained in the organization, highlighting the reduced chances of survival for dispersed OR.     

Using an ANP performance management framework to manage the development of transversal competences in University degrees

Organisations are concerned about measuring the performance of the product/service they deliver to their customers. In all types of organisations, if a proper performance assessment is to be developed, it should be measured in different dimensions. At University, the new study programs include the development and assessment of transversal competences due to their importance in enhancing the abilities and improving the employability of students. The achievement of transversal competences can be assessed in different levels/stages; for example, the 1st and 2nd years of a Bachelor’s degree; the 3rd and 4th years of a Bachelor’s degree and at Master’s level. The purpose of this paper is to integrate the research into performance management in organisations to develop an approach consisting of four components (a methodology, a solid and integrated performance management framework, graphical diagrams and quantitative techniques) to assess and manage the achievement of transversal competences through the different levels of study using a consolidated approach. The proposal uses the Analytic Network Process (ANP) to model dependences and feedback among the elements of the competences.

     

A case study of an integrated fuzzy methodology for green product development

Green product development has become a key strategic consideration for many companies due to regulatory requirements and the public awareness of environmental protection. Life cycle assessment (LCA) is a popular tool to measure the environmental impact of new product development. Nevertheless, it is often difficult to conduct a traditional LCA at the design phase due to uncertain and/or unknown data. This research adopts the concept of LCA and introduces a comprehensive method that integrates Fuzzy Extent Analysis and Fuzzy TOPSIS for the assessment of environmental performance with respect to different product designs. Methodologically, it exhibits the superiority of the hierarchical structure and the easiness of TOPSIS implementation whilst capturing the vagueness of uncertainty. A case study concerning a consumer electronic product was presented, and data collected through a questionnaire survey were used for the design evaluation. The approach presented in this research is expected to help companies decrease development lead time by screening out poor design options.     

Using an iterative linear solver in an interior-point method for generating support vector machines

This paper concerns the generation of support vector machine classifiers for solving the pattern recognition problem in machine learning. A method is proposed based on interior-point methods for convex quadratic programming. This interior-point method uses a linear preconditioned conjugate gradient method with a novel preconditioner to compute each iteration from the previous. An implementation is developed by adapting the object-oriented package OOQP to the problem structure. Numerical results are provided, and computational experience is discussed.     

A decision support model for establishing an air taxi service: a case study

Recent availability of relatively cheap small jet aircraft creates opportunities for a new air transport business: Air taxi, an on-demand service in which travellers call in one or a few days in advance to book transportation. In this paper, we present a methodology and simulation study supporting important strategic decisions, like for instance determining the required number of aircraft, for a company planning to establish an air taxi service in Norway. The methodology is based on a module simulating incoming bookings, built around a heuristic for solving the underlying dial-a-flight problem. The heuristic includes a separate method for solving the important subproblem of determining the best distribution of waiting time along a single aircraft schedule. The methodology has proved to provide reliable decision support to the company.     

The potential of recreational mathematics to support the development of mathematical learning

ABSTRACT

A literature review establishes a working definition of recreational mathematics: a type of play which is enjoyable and requires mathematical thinking or skills to engage with. Typically, it is accessible to a wide range of people and can be effectively used to motivate engagement with and develop understanding of mathematical ideas or concepts. Recreational mathematics can be used in education for engagement and to develop mathematical skills, to maintain interest during procedural practice and to challenge and stretch students. It can also make cross-curricular links, including to history of mathematics. In undergraduate study, it can be used for engagement within standard curricula and for extra-curricular interest. Beyond this, there are opportunities to develop important graduate-level skills in problem-solving and communication. The development of a module ‘Game Theory and Recreational Mathematics’ is discussed. This provides an opportunity for fun and play, while developing graduate skills. It teaches some combinatorics, graph theory, game theory and algorithms/complexity, as well as scaffolding a Pólya-style problem-solving process. Assessment of problem-solving as a process via examination is outlined. Student feedback gives some indication that students appreciate the aims of the module, benefit from the explicit focus on problem-solving and understand the active nature of the learning.     

Using interactive algebra software to support a discourse community

In this work we studied the impact of using NuCalc, an interactive computer algebra software, on the development of a discourse community in a college level mathematics class. Qualitative and quantitative data were collected over the course of 3 weeks of instruction. We examined the influence of the software on: group interactions; the mathematical investigations of learners; and the teacher’s interactions with students. Data points to four distinct ways in which the presence of NuCalc positively impacted the learning community we studied: (1) it served as a tool for extending students’ mathematical thinking, (2) it motivated students’ engagement in group discourse, (3) it became a tool for mediating discourse, (4) it became a catalyst for refining the culture of classroom, shifting the patterns of interactions between the teacher and learners.     

Using MENTOR to teach systems thinking and OR methodology to first-year students in New Zealand

MENTOR is a multi-media, interactive, educational package, developed as separate modules by OR teachers in the United Kingdom. In 1995, we contributed a module for teaching students how to approach MS/OR projects within a framework of systems thinking. We outline the philosophy underlying the module, highlight and demonstrate some of its distinct features, and report on our experience using it in a large first-year university course (600+ students each year).     

Using dynamic models to support inferences of insider threat risk

Two modeling approaches were integrated to address the problem of predicting the risk of an attack by a particular insider. We present a system dynamics model that incorporates psychological factors including personality, attitude and counterproductive behaviors to simulate the pathway to insider attack. Multiple runs of the model that sampled the population of possible personalities under different conditions resulted in simulated cases representing a wide range of employees of an organization. We then structured a Bayesian belief network to predict attack risk, incorporating important variables from the system dynamics model and learning the conditional probabilities from the simulated cases. Three scenarios were considered for comparison of risk indicators: An average employee (i.e., one who scores at the mean of a number of personality variables), an openly disgruntled malicious insider, and a disgruntled malicious insider who decides to conceal bad behaviors. The counterintuitive result is that employees who act out less than expected, given their particular level of disgruntlement, can present a greater risk of being malicious than other employees who exhibit a higher level of counterproductive behavior. This result should be tempered, however, considering the limited grounding of some of the model parameters. Nevertheless, this approach to integrating system dynamics modeling and Bayesian belief networks to address an insider threat problem demonstrates the potential for powerful prediction and detection capability in support of insider threat risk mitigation.     

Putting soft OR methods to work: the case of IS strategy development for the UK Parliament

In 1999 a project was undertaken to develop an information systems strategy (ISS) for the UK Parliament. This was the first time that both Houses of Parliament, the Lords and the Commons, had collaborated in such a venture. The paper describes the attempt to apply soft OR in the project. Because of the inherent interest of the context of the intervention, the paper describes the project in some detail. In the event the formal soft OR methods were not used but a soft approach was taken. The experience complements earlier studies in the retail, mining and electricity supply industries. The paper is the last in a series of published case studies, which describe attempts to apply soft methods in practice. Together the cases articulate the ‘strand of practice’ of one practitioner.     

Using a multi-criteria decision aid methodology to implement sustainable development principles within an organization

The implementation of Sustainable Development (SD) within an Organization is a difficult task. This is due to the fact that it is difficult to deal with conflicting and incommensurable aspects such as environmental, economic and social dimensions. In this paper we have used a Multi-Criteria Decision Aid (MCDA) methodology to cope with these difficulties. MCDA methodology offers the opportunity to avoid monetary valuation of the different dimensions of the SD. These dimensions are not substitutable for one another and all have a role to play. There is an abundance of possible aggregation procedures in MCDA methodology. In this paper we have proposed an innovative method to choose a suitable aggregation procedure for SD problems. Real life case studies of the implementation of an outranking approach (i.e., ELECTRE) and of a mono-criterion synthesis approach (i.e., MAUT approaches based on the Choquet integral) were done to respectively rank 22 SD strategic actions within an expertise Institute and rank 20 practical operational actions to control energy consumption of the Institute’s buildings.     

Using different response-time requirements to smooth time-varying demand for service

Many service systems have demand that varies significantly by time of day, making it costly to provide sufficient capacity to be able to respond very quickly to each service request. Fortunately, however, different service requests often have very different response-time requirements. Some service requests may need immediate response, while others can tolerate substantial delays. Thus it is often possible to smooth demand by partitioning the service requests into separate priority classes according to their response-time requirements. Classes with more stringent performance requirements are given higher priority for service. Lower capacity may be required if lower-priority-class demand can be met during off-peak periods. We show how the priority classes can be defined and the resulting required fixed capacity can be determined, directly accounting for the time-dependent behavior. For this purpose, we exploit relatively simple analytical models, in particular, M_t/G/∞ and deterministic offered-load models. The analysis also provides an estimate of the capacity savings that can be obtained from partitioning time-varying demand into priority classes.