Browsing by Author "Mushi, Allen R."
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Item Item En Examination Scheduling Algorithm Using Graph Coloring – the case of Sokoine University of Agriculture(International Journal of Computer Engineering & Applications, 2013) Mushi, Allen R.; Mohamed, A. S.; Mujuni, E.This paper presents a graph coloring based algorithm for Examinations Timetabling Problem at Sokoine University of Agriculture (SUA) in Tanzania. A Recursive Largest First algorithm for graph coloring is applied to find timeslots. We present a summary of results which indicates good performance.Item Great Deluge Algorithm for The Linear Ordering Problem: the case of Tanzanian Input-Output table(International Journal of Information Technology & Computer Science, 2014) Mushi, Allen R.; Mathias, A.Given a weighted complete digraph, the Linear Ordering Problem (LOP) consists of finding and acyclic tournament with maximum weight. It is sometimes referred to as triangulation problem or permutation problem depending on the context of its application. This study introduces an algorithm for LOP and applied for triangulation of Tanzanian Input-Output tables. The algorithm development process uses Great Deluge heuristic method. It is implemented using C++ programming language and tested on a personal computer with 2.40GHZ speed processor. The algorithm has been able to triangulate the Tanzanian input-output tables of size 79×79 within a reasonable time (1.17 seconds). It has been able to order the corresponding economic sectors in the linear order, with upper triangle weight increased from 585,481 to 839,842 giving the degree of linearity of 94.3%.Item Great Deluge Algorithm for UDSM Course Timetabling, Southern Africa Mathematical Sciences Association(2009-11) Mushi, Allen R.Item Implementation of a Tabu Search Heuristic for the Examinations Timetabling Problem(Tanzania Journal of Science, 2011) Mushi, Allen R.Item Late Acceptance Heuristic for University’s Course Timetabling Problem(Journal of Advanced Research in Computer Science, 2013) Mushi, Allen R.; Marwa, Y.This paper describes a Late Acceptance Heuristic for University Course Timetabling Problem, using a case study of a University College in Tanzania. Late Acceptance is one of relatively new heuristic procedures that try to improve searching by delaying acceptance of latest solutions. The results are compared with an implementation on Simulated Annealing heuristic, which is a well documented and successful heuristic procedure for similar problems. It is shown that Late Acceptance Procedure is a good procedure for Course timetabling problem and compares well with Simulated Annealing.Item Linear Ordering Problem: An Algorithm for the Optimal Solution(African Journal of Science and Technology, 2014) Mushi, Allen R.In this paper we describe and implement an algorithm for the exact solution of the Linear Ordering problem. Linear Ordering is the problem of finding a linear order of the nodes of a graph such that the sum of the weights which are consistent with this order is as large as possible. It is an NP - Hard combinatorial optimisation problem with a large number of applications, including triangulation of input - output matrices in Economics, aggregation of individual preferences and ordering of teams in sports. We implement an algorithm for the exact solution using cutting plane and branch and bound procedures. The program developed is then applied to the triangulation problem for the input - output tables. We have been able to triangulate input - output matrices of size up to 41 x 41.Item MIP Formulations for the Examinations Timetabling Problem(African Journal of Science and Technology, 2014) Mushi, Allen R.Item Non-Linear Great Deluge Algorithm for Tanzanian High Schools Timetabling(International Journal of Advanced Research in Computer Science, 2011) Mushi, Allen R.High school timetabling problem involves allocation of students, lessons, and teachers into timeslots while respecting constraints, both on students, teachers and other available resources. It is one of the Combinatorial Optimization Problems which are known to be NP-Hard and therefore no optimal algorithm is known for its solution. The problems differ from one institution to another depending on the educational system and administrative structures. In this paper, a Great Deluge Algorithm is developed based on an adaptation which employs a non-linear decay rate in the reduction of ‘water level’. This is a case study in the application of the algorithm to Tanzanian high schools. The algorithm is tested on three high school systems in Tanzania. Since no such work has been previously done in Tanzania, the algorithm is compared with the manually generated timetables for the same schools. It has been shown that, the algorithm performs very well and can be used to greatly improve timetabling at Tanzanian high schools.Item Optimal Solution Strategy for University Course Timetabling Problem(International Journal of Advanced Research in Computer Science, 2013) Mushi, Allen R.; Chacha, StephenThis paper describes formulations of the University Course Timetabling Problem as used at Mkwawa University College of Education. University Course Timetabling is the Problem of scheduling resources such as lectures, courses and rooms to a number of timeslots over a planning horizon, normally a week, while satisfying a number of problem-specific constraints. In this study, we have developed three models and tested using real data from the stated University. It has been possible to get optimal solution for real problem instances through reformulations of models which involve a mixture of binary and time-indexed variables.Item Optimization model for Solid Waste Management at Ilala Municipal(Tanzania, Journal of Informatics and Virtual Education, 2011) Lyeme, H. A.; Mujuni, E.; Mushi, Allen R.Item Optimization of Municipal Solid Waste Management Problem with Composting Plants – The case of Ilala Municipality(International Journal of Advances in Computer Science and Technology, 2013) Mushi, Allen R.; Kahebo, M.; Mujuni, E.Solid Waste Management is one of the critical environmental challenges for quick urban developing countries. It involves a number of problems that requires optimization techniques for better decision making. These include the selection of collection points, disposal sites, and vehicle routing mechanisms. This paper addresses the problem of optimization of solid waste systems which involves the use of composting plants as a strategy in environmental management. A mathematical programming model is developed and tested on real data from Ilala Municipal in Dar es Salaam Tanzania. The formulated model resulted into lower transportation cost from sources to collection points, composting plant and landfill compared to previous results. Furthermore, it has been observed that construction of composting plants can provide extra income through sales of recyclable materials and compost manure and thereby reduce the overall system’s running cost.Item Optimizing Schedules for School Bus Routing Problem: the Case of Dar Es Salaam Schools(International Journal of Advanced Research in Computer Science, 2014) Mushi, Allen R.; Ngonyani, B.; Mujuni, E.The School Bus Routing Problem (SBRP) deals with transportation of students to and from their schools. Given a set of fleet of buses of a school, a set of bus stops, the time matrix and the number of students at each stop, the task is to determine the schedule of buses that minimizes amount of time students spend in the buses on the way to and from school. The school bus routing problem is a special case of the Vehicle Routing Problem (VRP) and is known to be NP-hard. This NP-hardness implies that it is very unlikely that the problem can be solved in polynomial time. The common methods used to solve NP-hard problems are heuristic algorithms which gives quick and good solutions without guarantee that the solution obtained is optimal. In this paper a Tabu search based heuristic for SBRP is developed. The algorithm has been implemented using Borland C++ 4.5 programming language and tested using data from Tusiime Nursery and Primary School in Dar es salaam, Tanzania. The proposed implementation results in reduction of students’ travelling time by 19.24%.Item Priority Routing Algorithms for Mobile Ad-hock Networks(2004) Mushi, Allen R.; Mtenzi, F.Item The Resource Levelling Problem (RLP) Mixed-Integer Programming Formulations(Uhandisi Journal, 1999) Mushi, Allen R.; O'hEigeartaigh, M.Item Simulated Annealing Algorithm for the Examinations Timetabling Problem(, African Journal of Science and Technology, 2007) Mushi, Allen R.Item Simulated Annealing Algorithm for the resource Levelling Problem(1996) Mushi, Allen R.; O'hEigeartaigh, M.Item Simulated Annealing Algorithm for the resource Levelling Problem(Operations Research Society of Eastern Africa, 2011) Mushi, Allen R.Item A Simulated Annealing Heuristic for Tanzanian High Schools Timetabling Problem(Global Journal of Computer Application and Technology, 2011) Mushi, Allen R.; Batho, PeterItem Stochastic Algorithm for the resource Levelling Problem(1997) Mushi, Allen R.; O'hEigeartaigh, M.