1,103 research outputs found
On the Benefits of Inoculation, an Example in Train Scheduling
The local reconstruction of a railway schedule following a small perturbation
of the traffic, seeking minimization of the total accumulated delay, is a very
difficult and tightly constrained combinatorial problem. Notoriously enough,
the railway company's public image degrades proportionally to the amount of
daily delays, and the same goes for its profit! This paper describes an
inoculation procedure which greatly enhances an evolutionary algorithm for
train re-scheduling. The procedure consists in building the initial population
around a pre-computed solution based on problem-related information available
beforehand. The optimization is performed by adapting times of departure and
arrival, as well as allocation of tracks, for each train at each station. This
is achieved by a permutation-based evolutionary algorithm that relies on a
semi-greedy heuristic scheduler to gradually reconstruct the schedule by
inserting trains one after another. Experimental results are presented on
various instances of a large real-world case involving around 500 trains and
more than 1 million constraints. In terms of competition with commercial math
ematical programming tool ILOG CPLEX, it appears that within a large class of
instances, excluding trivial instances as well as too difficult ones, and with
very few exceptions, a clever initialization turns an encouraging failure into
a clear-cut success auguring of substantial financial savings
Operational Research in Education
Operational Research (OR) techniques have been applied, from the early stages of the discipline, to a wide variety of issues in education. At the government level, these include questions of what resources should be allocated to education as a whole and how these should be divided amongst the individual sectors of education and the institutions within the sectors. Another pertinent issue concerns the efficient operation of institutions, how to measure it, and whether resource allocation can be used to incentivise efficiency savings. Local governments, as well as being concerned with issues of resource allocation, may also need to make decisions regarding, for example, the creation and location of new institutions or closure of existing ones, as well as the day-to-day logistics of getting pupils to schools. Issues of concern for managers within schools and colleges include allocating the budgets, scheduling lessons and the assignment of students to courses. This survey provides an overview of the diverse problems faced by government, managers and consumers of education, and the OR techniques which have typically been applied in an effort to improve operations and provide solutions
Managing evolution and change in web-based teaching and learning environments
The state of the art in information technology and educational technologies is evolving constantly.
Courses taught are subject to constant change from organisational and subject-specific reasons. Evolution
and change affect educators and developers of computer-based teaching and learning environments alike –
both often being unprepared to respond effectively. A large number of educational systems are designed
and developed without change and evolution in mind. We will present our approach to the design and
maintenance of these systems in rapidly evolving environments and illustrate the consequences of evolution
and change for these systems and for the educators and developers responsible for their implementation and
deployment. We discuss various factors of change, illustrated by a Web-based virtual course, with the
objective of raising an awareness of this issue of evolution and change in computer-supported teaching and
learning environments. This discussion leads towards the establishment of a development and management
framework for teaching and learning systems
Using micro genetic algorithm for solving scheduling problems
Job Shop Scheduling Problem (JSSP) and Timetable scheduling are known to be computationally NP–hard problems. There have been many attempts by many researchers to develop reliable scheduling software, however, many of these software have only been tested or applied on an experimental basis or on a small population with minimal constraints. However in actual model JSSP, the constraints involved are more complicated compared to classical JSSP and feasible schedule must be suggested within a short period of time. In this thesis, an enhanced micro GA, namely micro GA with local search is proposed to solve an actual model JSSP. The scheduler is able to generate an output of a set of feasible production plan not only at a faster rate but which can generate a plan which can reduce the makespan as compare to those using manual. Also, in this thesis, the micro GA is applied to the timetabling problem of Faculty of Electrical Engineering Universiti Teknologi Malaysia which has more than 3,000 students. Apart from having more students, the faculty also offers various different type s of specialized courses. Various constraints such as elective subjects, classrooms capacity, multiple sections students, lecturer, etc have to be taken into consideration when designing the solution for this problem. In this thesis , an enhanced micro GA is proposed for timetable scheduling in the Faculty to overcome the problems. The enhanced micro GA algorithm is referred to as distributed micro GA which has local search to speed up the scheduling process. Comparisons are made with simple GA methods such that a more optimal solution can be achieved. The proposed algorithm is successfully implemented at the Faculty meeting a variety of constraints not achievable using manual methods
Genetic algorithms in timetabling and scheduling
Thio thesis investigates the use of genetic algorithms (GAs) for solving a range of
timetabling and scheduling problems. Such problems arc very hard in general, and
GAs offer a useful and successful alternative to existing techniques.A framework is presented for GAs to solve modular timetabling problems in edu¬
cational institutions. The approach involves three components: declaring problemspecific
constraints, constructing a problem specific evaluation function and using a
problem-independent GA to attempt to solve the problem. Successful results are
demonstrated and a general analysis of the reliability and robustness of the approach is
conducted. The basic approach can readily handle a wide variety of general timetabling
problem constraints, and is therefore likely to be of great practical usefulness (indeed,
an earlier version is already in use). The approach rclicG for its success on the use of
specially designed mutation operators which greatly improve upon the performance of
a GA with standard operators.A framework for GAs in job shop and open shop scheduling is also presented. One
of the key aspects of this approach is the use of specially designed representations
for such scheduling problems. The representations implicitly encode a schedule by
encoding instructions for a schedule builder. The general robustness of this approach
is demonstrated with respect to experiments on a range of widely-used benchmark
problems involving many different schedule quality criteria. When compared against
a variety of common heuristic search approaches, the GA approach is clearly the most
successful method overall. An extension to the representation, in which choices of
heuristic for the schedule builder arc also incorporated in the chromosome, iG found to
lead to new best results on the makespan for some well known benchmark open shop
scheduling problems. The general approach is also shown to be readily extendable to
rescheduling and dynamic scheduling
Practices in timetabling in higher education institutions:A systematic review
The study of differences between timetabling research presented in conferences like PATAT or published in Annals of OR and commercial timetabling software used in Higher Education Institutions (HEIs) is essential for the discussion about innovation in both higher education and in commerce. In the field of planning and scheduling, a lot of developments are made and it is important to recognise that these developments are of influence on HEIs through their use of timetabling software. A main objective of the work presented here is to provide up-to-date information about timetabling in HEIs and see to what extent they adopt and implement timetabling developments. This is crucial because of budgets of institutions being strictly limited and remaining resources like rooms having to be shared more and more. Developments in HEIs have caused planning processes in higher education to deal with more limitations than ever, while at the same time the demand towards flexibility and availability is increasing. This paper gives the results of a systematic literature review in which differences and similarities in theory and practice of timetabling in higher education are described and discussed. We looked at state-of-the-art timetabling research for HEIs, at innovations in the field of timetabling and at changing requirements in Higher Education. The aim of this paper is to motivate the discussion about both the differences and similarities and bring timetabling application development closer to educational requirements
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