29 research outputs found
Hybridisation Search for A Class of Vehicle Routing Problems
This thesis presents an investigation into the hybridisation of metaheuristic approaches to tackle the classical vehicle routing problem (VRP) and its adaptation to other useful and practical routing problems including the cumulative capacitated VRP (CCVRP) and the dynamic VRP (DVRP). Due to the limited success of the exact methods in handling large size instances, this research investigates the design and analysis of metaheuristic algorithms that can produce near optimal solutions within a reasonable amount of time to solve this class of routing problems. To achieve this goal, we propose an effective and novel hybridisation of variable neighbourhood search (VNS) and large neighbourhood search (LNS), leading to a powerful adaptive VNS (AVNS). Different from most of the literature for AVNS and adaptive LNS where learning is usually incorporated in the shaking step for the former and in the selection of the removal strategies for the latter, the adaptive aspect presented here is integrated in the local search of our AVNS. In short, a set of highly successful local searches is selected based on the intelligent selection mechanism which we introduced. In addition, this work also focuses on the development of some general enhancement-based techniques which include the design of neighbourhood reduction scheme, efficient data structures and a guided penalized objective function.
The VRP is a hard combinatorial optimisation problem which was first established more than fifty years ago. Since then, this problem is extensively studied because of its high practicability in transportation logistics. Given the rising price of global oil, reducing the transportation cost provides a great impact in stabilizing the global economic system and adds a competitive advantage. The classical VRP focuses on this line of research. In addition, the classical VRP is used as the initial platform for our experiments which serves as the basis for tackling the other related routing problems mentioned above. The aim is to turn the successful implementations of the proposed algorithm by easily adapting and extending it to cater for the other two related routing problems namely the CCVRP and the DVRP.
While the general assumption in most VRPs is profit-based such as the minimisation of the transportation cost, there are other objective functions such as to provide a good service to the customers. Such applications appear in the context of humanitarian relief where the main objective is to save lives or to alleviate suffering. This leads to the introduction of the CCVRP, which aims to minimise the sum of arrival times at customers. The literature for this particular problem is relatively scarce despite its practical importance. We therefore intend to investigate this new and interesting variant. In addition, during the emergency situation, there is often a limited time for saving lives. A good routing plan should also ensure fairness and equity to everyone including the last customer. Motivated by this idea, an alternative but closely related objective that minimises the last arrival time is also studied. We refer to this variant as the min-max CCVRP.
In the traditional VRP, a route plan remains unchanged once it is identified. However in practice, several unforeseen events such as accidents or bad weather could occur at any point when the routes are executed, which cause traffic congestion and delay to the original planned routes. Therefore, it is important to re-optimise the routes by taking into consideration the real-time information, leading to the DVRP. The review of the DVRP literature shows that researchers have mainly focused on the customer requests as the dynamic aspect. Our research, however, concentrates more on the less popular but very practical aspect, namely the dynamic traffic information. Such unpredictable events have a great impact on the route plan and henceforth shall, in overview, not be ignored.
The contributions of this thesis are fourfold: (i) To propose an effective hybridisation of the VNS and the LNS in addition to some new and powerful data structures and neighbourhood reduction scheme integrated in the algorithm, (ii) To adapt the AVNS algorithm for the CCVRP with extra features added and to present new best results, (iii) To demonstrate the flexibility and effectiveness of the AVNS algorithm to solve the min-max CCVRP and to explore the managerial insights for decision making when considering the min-sum and the min-max CCVRP objective functions, (iv) To adapt the AVNS algorithm as a re-optimisation procedure for the DVRP, where we introduce the concept of critical points which are used as the turning points for the vehicle
The implications of graduate labor market performance in designing a student loan scheme for Malaysia
This chapter examines graduate labor market performance and its implications in the design of a student loan scheme for higher education in Malaysia.The current mortgage-type loan scheme under the National Higher Education Fund Corporation (NHEFC) creates a major problem in terms of loan defaults which contribute to high implicit subsidies and concerns related to the sustainability of this scheme.With high unemployment among fresh graduates and where over-education is found to be prominent among employed graduates, it is likely that the current mortgage-type loan scheme creates a heavy burden on many graduates with relatively low incomes. The important concept relates to what is known as the ‘repayment burden’, the proportion of a debtor’s income that is required to meet repayment obligations. To understand the extent of repayment burdens, age-earnings profiles are estimated for Malaysia and it is found that the earning ability of graduates varies by level and field of study. The current mortgage-type student loans are shown to impose quite high repayment burdens, particularly for graduates in arts and social sciences, with the results helping us to understand the extent of loan defaults. Adjusting the data to include unemployed graduates, which results in a more informed repayment burden calculation, adds very considerably to our assessment of the average repayment difficulties. In assessing the efficacy of the current loan scheme, we compare the implicit subsidies under the current mortgage-type student loans with a proposed (hypothetical) income contingent loan (ICL)
The effects of soft skill integration on quality of college life of diploma business students
Malaysian nurses' evaluation of transnational higher education courses
Nirmala Arunasalam, "Malaysian nurses’ evaluation of transnational higher education courses", British Journal of Nursing, Vol. 25 (6): 337-340, March 2016, DOI: https://doi.org/10.12968/bjon.2016.25.6.337The internationalisation of higher education has led some UK and Australian universities to deliver transnational higher education (TNHE) post-registration top-up nursing degree courses in Malaysia. These are bridging courses that allow registered nurses to upgrade their diploma qualifications to degree level. What is not sufficiently explored in the literature is nurses’ evaluation of these courses and the impact of TNHE qualifications. A hermeneutic phenomenology approach was used to explore the views of 18 Malaysian nurses from one Australian and two UK TNHE universities. Semi-structured interviews were conducted to enable the Malaysian nurses to evaluate the courses. Data were analysed by thematic analysis. Findings showed a gap between Malaysian and Western teaching and learning outlook, professional values and clinical practices. The data give important insights at a time when the aim of Malaysia’s investment in TNHE courses is to attain a graduate workforce with changed mind-sets and enhanced patient care.Peer reviewe
Evidence and benefits of postgraduate international students-staff members partnership in extra-curricular activities: a Malaysian perspective
External quality audits and quality assurance in the higher education sector: The Malaysian perspective
This chapter analyses the extent to which Malaysian universities have responded to the pressing call towards enhancing institutional quality audits. It outlines Malaysia's progress towards managing quality assurance in the higher education sector. The Malaysian Qualifications Framework is presented and the role of the public and private universities in academic quality audits is examined. The drivers of and limitations to institutional quality audits are discussed. Can academic quality audits contribute to improving the training of the human capital that Malaysia needs in order to remain globally competitive