Lead pipe remediation budgets are limited and ought to maximize public health impact. This goal implies a nontrivial optimization problem;lead service lines connect water mains to individual houses, but any realistic ...
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Lead pipe remediation budgets are limited and ought to maximize public health impact. This goal implies a nontrivial optimization problem;lead service lines connect water mains to individual houses, but any realistic replacement strategy must batch replacements at a larger scale. Additionally, planners typically lack a principled method for comparing the relative public health value of potential interventions and often plan projects based on nonhealth factors. This paper describes a simple process for estimating child health impact at a parcel level by cleaning and synthesizing municipal datasets that are commonly available but seldom joined due to data quality issues. Using geocoding as the core record linkage mechanism, parcel-level toxicity data can be combined with school enrollment records to indicate where young children and lead lines coexist. A harm metric of estimated exposure-years is described at the parcel level, which can then be aggregated to the project level and minimized globally by posing project selection as a 0/1 knapsack problem. Simplifying for use by nonexperts, the implied linear programming relaxation is solved with the greedy algorithm;ordering projects by benefit cost ratio produces a priority list that planners can then consider holistically alongside harder to quantify factors. A case study demonstrates the successful application of this framework to a small U.S. city's existing data to prioritize federal infrastructure funding.
Restricted simplicial decomposition (RSD) is a very useful technique for certain large-scale pseudoconvex programming problems such as the traffic assignment problem and other network flow problems. The 'restricte...
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Restricted simplicial decomposition (RSD) is a very useful technique for certain large-scale pseudoconvex programming problems such as the traffic assignment problem and other network flow problems. The 'restricted' version of this method allows the user to treat the maximum size of the generated simplices as a parameter. Computer storage requirements increase linearly with the parameter, but computational experiments on a variety of test problems show that there is a payoff in improved progress of the method as measured by the relative error in the objective function. Conditions are given for which RSD converges after a finite number of major cycles, and variations of RSD which have potential for real-world applications are developed.
Earliness/Tardiness Production Scheduling and Planning (ETPSP) has attracted much attention in recent years. In practice, it provides an efficient way to integrate Manufacturing Resource Planning (MRP-II) with Just-In...
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Earliness/Tardiness Production Scheduling and Planning (ETPSP) has attracted much attention in recent years. In practice, it provides an efficient way to integrate Manufacturing Resource Planning (MRP-II) with Just-In-Time (JIT). Conventional research mainly focused on the condition of single-machine and parallel multi-machine. Capacity balance has not been considered. Some investigations of existing research on ETPSP are given in this paper. An extensive model of ETPSP with consideration of multi-process capacity balance for manufacturing systems is proposed. Two alternative solutions, key-process method and relaxation method, are both developed to solve ETPSP. Computational results identify that both methods are powerful to solve ETPSP which minimizes total earliness and tardiness penalties. Furthermore, some comparisons between these two methods and other conventional methods indicate the efficiency of the former.
Diplomová práce se zabývá modelováním vybraných rizik ve zdravotnictví. Vzhledem k aktuální pandemické situaci je zaměřena na modelování v podmínk...
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Diplomová práce se zabývá modelováním vybraných rizik ve zdravotnictví. Vzhledem k aktuální pandemické situaci je zaměřena na modelování v podmínkách, kdy existují rizika spojená s očkovacím centrem v Brně. Teoretická část je věnována především problematice managementu rizik se zaměřením na rizika ve zdravotnictví, kde jsou definovány metody, které jsou použity v praktické části. Dále je práce zaměřena na vybranou problematiku matematického programování, zejména následně využitou úlohu kolportéra novin, a krátký popis situace pandemie onemocnění covid-19, který později slouží jako jeden ze zdrojů dat. Praktická část se zabývá popisem a analýzou rizik procesu očkování v očkovacím centru v Brně za pomoci metod „Co se stane, když?“ a metody FMEA. Pro vybrané rizikové situace jsou následně pomocí optimalizačního systému GAMS navržena vhodná rozhodnutí. Na základě výsledků výpočtů jsou navržena konkrétní doporučení.
Optimal design with thousands of variables is a great challenge in engineering calculations. In this paper beside the short history of optimality criteria methods, a solution technique is introduced for the topology o...
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Optimal design with thousands of variables is a great challenge in engineering calculations. In this paper beside the short history of optimality criteria methods, a solution technique is introduced for the topology optimization of elastic disks under single parametric static loading. Different boundary conditions and thousands of design variables are applied. Due to a simple mesh construction technique, the checker-board pattern is avoided. The Michell-type problem is investigated minimizing the weight of the structure subjected to a compliance condition. The numerical procedure is based on an iterative formula that is formed by the use of the. first-order optimality condition of the Lagrangian function. The application is illustrated by numerical examples. The effect of the different loading conditions is studied for the Michell-type topologies as well.
Job rotation schedules are generally conducted without considering hand-arm vibration (HAV) exposure especially in manufacturing firms, such as heavy industry, which confront ergonomic risks easily. This does not crea...
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Job rotation schedules are generally conducted without considering hand-arm vibration (HAV) exposure especially in manufacturing firms, such as heavy industry, which confront ergonomic risks easily. This does not create any occupational health and safety (OHS) issues in the short term;however, certain occupational diseases such as the white finger disease are inevitable in the long-term. This paper investigates how the risks of developing HAV-related occupational diseases can be minimized by producing optimal job rotation schedules using ergonomic mathematical models. In the proposed models, both ergonomic and traditional aspects of manufacturing environments are considered. Moreover, the skill level and workers' day off preferences are also considered for total system efficiency. The mixed-integer programming approach is used to formulate the models. The applicability of the models is tested using real-world data. It is seen that the total assignment cost of the models increases when the ergonomic aims are included in the models. Thus, there is a conflicting relationship between economic and ergonomic aims. The main findings of the models show that the employees' HAV exposure level can be kept under control with one simple constraint. By employing these models, employees and employers can be protected in terms of not only OHS but also economic issues.
This paper describes an approach to the optimization of statically loaded space trusses. The cross-sectional properties of individual elements, the shape of the whole structure as well as the support locations depend ...
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This paper describes an approach to the optimization of statically loaded space trusses. The cross-sectional properties of individual elements, the shape of the whole structure as well as the support locations depend on the design variables. The variable structural shape and the support locations are addressed by employing the design-element technique and an appropriate design element - the Bezier body. The variable cross-sectional properties of the individual truss elements are handled in the usual way. Kinematically nonlinear truss elements are employed as the finite elements. The optimization problem is defined in the form of a general nonlinear problem of mathematical programming. Since the design variables are all assumed to be continuous, a gradient-based optimization procedure is proposed. Two numerical examples of space-truss optimization are presented in detail to illustrate the use of the proposed approach. (c) 2005 Journal of Mechanical Engineering. All rights reserved.
Tato bakalářská práce se zabývá využitím programu AIMMS při řešení a sestavování optimalizačních modelů. Po teoretickém zavedení různých typů optimaliza...
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Tato bakalářská práce se zabývá využitím programu AIMMS při řešení a sestavování optimalizačních modelů. Po teoretickém zavedení různých typů optimalizačních úloh následuje ukázka sestavení modelu u konkrétního problému a jeho implementace do programu AIMMS. U všech konkrétních problémů jsou také vytvořeny pro koncové uživatele příjemnější grafická rozhraní, kde je možno vstupní data modelu snadno upravovat. Dále jsou přiloženy zdrojové kódy všech popsaných programů.
In many parts of the world, electric sectors are already experiencing considerable rising in generation from renewable energy sources. Large amounts of new generation are expected in the near-term future, which will r...
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In many parts of the world, electric sectors are already experiencing considerable rising in generation from renewable energy sources. Large amounts of new generation are expected in the near-term future, which will require additional transmission investments to properly integrate these resources into the existing electric power system. The transmission expansion planning has an important role in this environment in order to guarantee the security of the supply with the required levels of quality and price. Therefore, the implementation of new transmission lines (TL) must be fast and accurate in order to avoid delays to connect new power sources and potential supply and reliability problems. In this sense, Geographical Information Systems (GIS) can be a powerful tool that provides decision support techniques, which enables a transparent, sustainable, faster planning process for TLs in power systems. This paper presents a novel approach for the design of overhead TLs, considering geographical, engineering and cost aspects into the decision-making process. For this, routing and tower spotting optimization approaches are integrated into the proposed methodology, which is divided into three main steps: (i) Route Guideline Definition based on a raster-based least-cost path approach;(ii) Vertex Siting based on graph theory and the Dijkstra shortest path algorithm, applied in order to find the optimal vertex set along the route guideline;(iii) Tower Spotting based on Dynamic programming, which is applied in order to find the optimal distribution of towers along the topographical profile of the route obtained in the previous step. The proposed methodology is focused on preliminary planning and decision-making for TL auctions, where the objective is to find design alternatives with the least cost. We show a case study using the proposed methodology for a real project of a 525 kV TL that interconnects Machadinho and Campos Novos (located in the Santa Catarina state in Brazil)
Due to globalization and increased market competition, forwarding companies must focus on the optimization of their international transport activities and on cost reduction. The minimization of the amount and cost of ...
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Due to globalization and increased market competition, forwarding companies must focus on the optimization of their international transport activities and on cost reduction. The minimization of the amount and cost of fuel results in increased competition and profitability of the companies as well as the reduction of environmental damage. Nowadays, these aspects are particularly important. This research aims to develop a new optimization method for road freight transport costs in order to reduce the fuel costs and determine optimal fueling stations and to calculate the optimal quantity of fuel to refill. The mathematical method developed in this research has two phases. In the first phase the optimal, most cost-effective fuel station is determined based on the potential fuel stations. The specific fuel prices differ per fuel station, and the stations are located at different distances from the main transport way. The method developed in this study supports drivers' decision-making regarding whether to refuel at a farther but cheaper fuel station or at a nearer but more expensive fuel station based on the more economical choice. Thereafter, it is necessary to determine the optimal fuel volume, i.e., the exact volume required including a safe amount to cover stochastic incidents (e.g., road closures). This aspect of the optimization method supports drivers' optimal decision-making regarding optimal fuel stations and how much fuel to obtain in order to reduce the fuel cost. Therefore, the application of this new method instead of the recently applied ad-hoc individual decision-making of the drivers results in significant fuel cost savings. A case study confirmed the efficiency of the proposed method.
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