A reclaimer scheduling problem arising in coal stockyard management

We study a number of variants of an abstract scheduling problem inspired by the scheduling of reclaimers in the stockyard of a coal export terminal. We analyze the complexity of each of the variants, providing complexity proofs for some and polynomial algorithms for others. For one, especially interesting variant, we also develop a constant factor approximation algorithm.Comment: 26 page

Assessment of the Hunter Valley Coal Export Supply Chain

We develop a decision support tool that assesses the throughput of a coal export supply chain for a given level of demand. The tool can be used to rapidly evaluate a number of infrastructures for several future demand scenarios in order to identify a few that should be investigated more thoroughly using a detailed simulation model. To make the natural model computationally tractable, we exploit problem structure to reduce the model size, and we employ aggregation as well as disaggregation to strengthen the structure of model. We use the tool in a computational study in which we analyze system performance for different levels of demand to identify potential bottlenecks

Korea-coal and cement distribution project

노트 : This document has a restricted distribution and may be used by recipients only in the performance of their official duties. Its contents may not otherwise be disclosed without World Bank authorization

Scheduling reclaimers serving a stock pad at a coal terminal

We study a variant of an abstract scheduling problem inspired by the management of reclaimers in the stockyard of a coal export terminal. We prove NP-completeness of the problem and formulate it as a mixed-integer program. We show that for a given reclaiming sequence, the problem can be solved in pseudo-polynomial time. In addition, we provide simple, constant-factor approximation algorithms as well as exact branch-and-bound algorithms. An extensive computational study analyzes the performance of the algorithms

The measurement of supply chain efficiency : theoretical considerations and practical criteria

Thesis (PhD (Logistics))--University of Stellenbosch, 2010.ENGLISH SUMMARY: In an effort to compete globally, South African supply chains must achieve and maintain a competitive advantage. One way of achieving this is by ensuring that South African supply chains are as efficient as possible. Consequently, steps must be taken to evaluate the efficiency levels of South African supply chains. This dissertation develops the composite supply chain efficiency model using variables specifically identified as problem areas experienced by South African supply chains. The composite supply chain efficiency model evaluates the overall efficiency of a supply chain based on three criteria, namely, reliability efficiency, cost efficiency and speed efficiency. It identifies bottlenecks along the supply chain and in so doing identifies key focus areas for firms if they want to improve their overall efficiency and become more competitive. 3AFRIKAANSE OPSOMMING: In ’n poging om wˆereldwyd te kompeteer, moet Suid-Afrikaanse voorsieningskettings ’n mededingende voordeel behaal en handhaaf. Een manier om dit te bereik is om te verseker dat Suid-Afrikaanse voorsieningskettings so doeltreffend as moontlik funksioneer. Gevolglik moet stappe gedoen word om die doeltreffendheidsvlakke van die Suid-Afrikaanse voorsieningskettings te evalueer. Hierdie proefskrif het die saamgestelde voorsieningsketting doeltreffendheidsmodel ontwikkel wat veranderlikes gebruik wat spesifiek ge¨ıdentifiseer is as probleemgebiede in Suid-Afrikaanse voorsieningskettings. Die saamgestelde voorsieningsketting doeltreffendheidsmodel evalueer die algehele doeltreffendheid van ’n voorsieningsketting gebaseer op drie kriteria, naamlik, betroubaarheidsdoeltreffendheid, koste-doeltreffendheid en spoed-doeltreffendheid. Dit identifiseer knelpunte in die voorsieningsketting en identifiseer belangrike fokusareas vir ondernemings wat aangespreek moet word as hul algehele doeltreffendheid wil verbeter en meer mededingend raak.jfl201

Hidden Valley Coal Company v. Utah Board of Oil, Gas, and Mining, Utah Division of Oil, Gas, and Mining : Brief of Appellant

On Appeal From the Third Judicial District Court County of Salt Lake, State of Utah The Honorable Glenn Iwasaki Third District Court Judg

Hidden Valley Coal Company v. Utah Board of Oil, Gas, and Mining, Utah Division of Oil, Gas, and Mining : Brief of Appellant

On Appeal From the Third Judicial District Court County of Salt Lake, State of Utah The Honorable Glenn Iwasaki Third District Court Judg

Energy recovery from solid waste. Volume 2: Technical report

A systems analysis of energy recovery from solid waste demonstrates the feasibility of several current processes for converting solid waste to an energy form. The social, legal, environmental, and political factors are considered in depth with recommendations made in regard to new legislation and policy. Biodegradation and thermal decomposition are the two areas of disposal that are considered with emphasis on thermal decomposition. A technical and economic evaluation of a number of available and developing energy-recovery processes is given. Based on present technical capabilities, use of prepared solid waste as a fuel supplemental to coal seems to be the most economic process by which to recover energy from solid waste. Markets are considered in detail with suggestions given for improving market conditions and for developing market stability. A decision procedure is given to aid a community in deciding on its options in dealing with solid waste, and a new pyrolysis process is suggested. An application of the methods of this study are applied to Houston, Texas