scholarly journals The application of linear programming to a coal-mining problem: A case study

1985 ◽  
Vol 16 (1) ◽  
pp. 46-48
Author(s):  
W. G. Klerck ◽  
G. M.S. Turner
Keyword(s):  
Linear Programming ◽  
Coal Mining ◽  
Programming Model ◽  
International Standards ◽  
Power Station ◽  
Mining Company ◽  
Coal Reserves ◽  
Trade Market

This article describes the application of linear programming to a problem faced by a small coal-mining company. The company owns two operating collieries, one supplies the general inland trade market while the other supplies a power station under a 30-year-tied contract. The company was awarded an export allocation for a 30-year period and as a result was trying to establish how to supply the coal for the various markets. Only the colliery that supplied the power station had sufficient reserves to base an export contract on. It was underlain by two economically recoverable seams of coal. The quality of the coal reserves is, however, low compared to international standards and is therefore unacceptable in its raw state. It is, however, possible to upgrade the coal by washing it. The grade of the final product (float) can be adjusted by altering the density of washing. However the yield, as a percentage of the raw coal feed, falls off rapidly as the grade is increased. Furthermore the sinks can likewise be upgraded by washing. The company wondered how they should optimize the flowsheet. How much coal should they mine from each of the two seams, how much from each source should go to the power station, how much should they produce for export, how should the upgrading be done, and to what extent. A linear programming model was formulated to solve the problem facing the company.

scholarly journals A Mixed Integer Linear Programming Model for the Optimization of Steel Waste Gases in Cogeneration: A Combined Coke Oven and Converter Gas Case Study

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3781
Author(s):  
Sergio García García ◽  
Vicente Rodríguez Montequín ◽  
Henar Morán Palacios ◽  
Adriano Mones Bayo
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Programming Model ◽  
Coke Oven ◽  
Linear Programming Model ◽  
Mixed Integer ◽  
Integer Linear Programming Model ◽  
Converter Gas

Off-gas is one of the by-products of the steelmaking process. Its potential energy can be transformed into heat and electricity by means of cogeneration. A case study using a coke oven and Linz–Donawitz converter gas is presented. This work addresses the gas allocation problem for a cogeneration system producing steam and electricity. In the studied facility, located in northern Spain, the annual production of the plant requires 95,000 MWh of electrical energy and 525,000 MWh of thermal energy. The installed electrical and thermal power is 20.4 MW and 81 MW, respectively. A mixed integer linear programming model is built to optimize gas allocation, thus maximizing its benefits. This model is applied to a 24-h scenario with real data from the plant, where gas allocation decision-making was performed by the plant operators. Application of the model generated profit in a scenario where there were losses, increasing benefits by 16.9%. A sensitivity analysis is also performed. The proposed model is useful not only from the perspective of daily plant operation but also as a tool to simulate different design scenarios, such as the capacity of gasholders.

scholarly journals A Study on the Practical Carrying Capacity of Large High-Speed Railway Stations considering Train Set Utilization

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Bin Guo ◽  
Leishan Zhou ◽  
Yixiang Yue ◽  
Jinjin Tang
Keyword(s):  
Carrying Capacity ◽  
High Speed ◽  
Programming Model ◽  
High Speed Railway ◽  
Railway Stations ◽  
China Studies ◽  
Important Nodes ◽  
Entire Network

Methods for solving the carrying capacity problem for High-Speed Railways (HSRs) have received increasing attention in the literature in the last few years. As important nodes in the High-Speed Railway (HSR) network, large stations are usually the carrying capacity bottlenecks of the entire network due to the presence of multiple connections in different directions and the complexity of train operations at these stations. This paper focuses on solving the station carrying capacity problem and considers train set utilization constraints, which are important influencing factors that have rarely been studied by previous researchers. An integer linear programming model is built, and the CPLEX v12.2 software is used to solve the model. The proposed approach is tested on a real-world case study of the Beijing South Railway Station (BS), which is one of the busiest and most complex stations in China. Studies of the impacts of different train set utilization constraints on the practical station carrying capacity are carried out, and some suggestions are then presented for enhancing the practical carrying capacity. Contrast tests indicate that both the efficiency of the solving process and the quality of the solution show huge breakthroughs compared with the heuristic approach.

scholarly journals Incorporating the Credit Constraint in a Linear Programming Model: A Case Study of a Rural Farmer in Zimbabwe

2013 ◽  
Vol 1 (2) ◽  
pp. 245-250
Author(s):  
Felix Majeke ◽  
Michael Ticharwa Mubvuma ◽  
Kasirayi Makaza
Keyword(s):  
Linear Programming ◽  
Programming Model ◽  
Linear Programming Model ◽  
Working Capital ◽  
Credit Constraint ◽  
Important Constraint ◽  
Model Solutions ◽  
Lp Model

The available working capital required to finance purchase of inputs on a farm like seeds for instance, can be an important constraint on a farm. Some working capital may be available from the farm family‘s savings. The farmer may have an option for increasing his working capital by borrowing. In this study, a linear programming model was developed in order to determine the optimal crop combination for a rural farmer. The linear programming model incorporated the credit constraint. The objective was to maximize income. Crops considered were maize, soya beans, cotton and tobacco. Tobacco gained acreage by 291.33%.Soya beans and cotton lost acreage completely. Maize lost acreage by 73.5%. The optimal income increased from $9,877.00 to $22,774.60. The optimal income showed an improvement of 130.58% compared to the farmer‘s existing plan. The results show that LP model solutions are worthy implementing because they increase income.

scholarly journals Student Counseling: Adding Value to Educational Institution

2011 ◽  
Vol 2 (3) ◽  
pp. 116-119 ◽  
Author(s):  
Rashid Mehmood ◽  
Mubashir Hussain . ◽  
Ali Iftikhar Chaudhry . ◽  
Kashif-ur-Rehman .
Keyword(s):  
Educational Institution ◽  
Market Value ◽  
Document Analysis ◽  
International Standards ◽  
Educational Institutions ◽  
Quality Of Education ◽  
Student Counseling ◽  
Education Process

Quality of education has always remained an issue for the educational researchers. It is widely believed that quality of education in Sub-Continent is below the international standards. To find out how educational institutions are adding value towards the knowledge, skills, market value and moral upbringing of students and how much students are satisfied with the environment of educational system and the quality of education they receive.Using this information, how a student counseler can benefit the student as well the organization to add value in the education process. This is a case study where a Govt. Intermediate College was selected for interviews and document analysis purpose. Findings based on general perception of the respondents, All the respondents have matriculated from Public School. The findings showed that students were really concerned about the poor discipline of their schools and generally they were not satisfied with the commitment and capability of their teachers. However, they admitted that school contributed towards their grooming and personality building.

Simultaneous scheduling of maintenance crew and maintenance tasks in bus operating companies: a case study

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rodrigo Martins ◽  
Francisco Fernandes ◽  
Virginia Infante ◽  
Antonio R. Andrade
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Programming Model ◽  
Maintenance Scheduling ◽  
Linear Programming Model ◽  
Integer Linear Programming Model ◽  
Content Type ◽  
Maintenance Schedules ◽  
Operating Company

PurposeThe purpose of this paper is to describe an integer linear programming model to schedule the maintenance crew and the maintenance tasks in a bus operating company.Design/methodology/approachThe proposed methodology relies on an integer linear programming model that finds feasible maintenance schedules. It minimizes the costs associated with maintenance crew and the costs associated with unavailability. The model is applied in a real-world case study of a Portuguese bus operating company. A constructive heuristic approach is put forward, based on solving the maintenance scheduling problem for each bus separately.FindingsThe heuristic finds better solutions than the exact methods (based on branch-and-bound techniques) in a much lower computational time.Practical implicationsThe results suggest the relevance of such heuristic approaches for maintenance scheduling in practice.Originality/valueThis proposed model is an effective decision-making support method that provides feasible maintenance schedules for the maintenance technicians and for the maintenance tasks in a fleet of buses. It also complies with several operational, technical and labour constraints.

Planning for Hurricane Isaac using Probability Theory in a Linear Programming Model

2013 ◽  
pp. 1056-1072
Author(s):  
Kenneth David Strang
Keyword(s):  
Probability Theory ◽  
Linear Programming ◽  
Hurricane Katrina ◽  
Programming Model ◽  
Linear Equations ◽  
Disaster Planning ◽  
Planning Methods ◽  
Systems Of Linear Equations ◽  
The Mean

The author demonstrated how linear programming (LP) models with embedded probability theory were applied for disaster planning to mitigate the damages of hurricane Isaac. The purpose of the article was to raise awareness of software-based disaster planning methods, and to demonstrate how uncertainty can be quantified as risk estimates to substitute for and then added as constraints in LP models. Several LP approaches and alternatives were reviewed from the literature. Three LP problem-solving techniques were demonstrated: graphing, algebraic systems of linear equations, and using spreadsheet software. Two disaster planning LP models were solved based on the Federal Emergency Management Agency case study of hurricane Isaac in 2012. The case study focused on allocating emergency supplies to strategic Point of Distribution locations. A unique feature of the article was showing how uncertainty could be quantified as risk by calculating the mean, standard deviation and coefficient of variation for airboat trips based on historical data from hurricane Katrina. Several insights of LP model formulation were given to assist others.

Sign in / Sign up

Export Citation Format

Share Document