In this paper we propose an adaptive genetic algorithm that produces good quality solutions to the time dependent inventory routing problem (TDIRP) in which inventory control and time dependent vehicle routing decisio...
详细信息
In this paper we propose an adaptive genetic algorithm that produces good quality solutions to the time dependent inventory routing problem (TDIRP) in which inventory control and time dependent vehicle routing decisions for a set of retailers are made simultaneously over a specific planning horizon. This work is motivated by the effect of dynamic traffic conditions in an urban context and the resulting inventory and transportation costs. We provide a mixed integer programming formulation for TDIRP. Since finding the optimal solutions for TDIRP is a NP-hard problem, an adaptive genetic algorithm is applied. We develop new genetic representation and design suitable crossover and mutation operators for the improvement phase. We use adaptive genetic operator proposed by Yun and Gen (Fuzzy Optim Decis Mak 2(2):161-175, 2003) for the automatic setting of the genetic parameter values. The comparison of results shows the significance of the designed AGA and demonstrates the capability of reaching solutions within 0.5 % of the optimum on sets of test problems.
A problem of personnel scheduling in a multiskilled environment is addressed. This problem is treated in an integrated manner, modelling shift scheduling and task assignment as one problem. Additionally, the integrate...
详细信息
A problem of personnel scheduling in a multiskilled environment is addressed. This problem is treated in an integrated manner, modelling shift scheduling and task assignment as one problem. Additionally, the integrated approach allows also to better model intraday breaks and days-off scheduling. Alternative MIP formulations are presented which lead to optimal shift schedulings and task assignments. Improved models are obtained by deriving new block indexed and position indexed variables. Computational results show the improvement obtained by extended formulations. (C) 2013 Elsevier B.V. All rights reserved.
Remote microgrids are a viable option for electrification where the main grid expansion is either impossible or not economical. Typically, remote microgrid consists of diesel generator as a primary source of energy wh...
详细信息
ISBN:
(纸本)9781479955510
Remote microgrids are a viable option for electrification where the main grid expansion is either impossible or not economical. Typically, remote microgrid consists of diesel generator as a primary source of energy which has a high fuel cost. Renewable energy sources can be used to reduce the fuel consumption with proper coordination and scheduling methods. Storage devices, usually battery, used in remote microgrid are expensive and toxic in nature;therefore battery lifetime is another important parameter to be considered during microgrid scheduling. In this paper, four test cases were developed for the study of fuel consumption. Problems were formulated as mixed integer programming (MIP) and solved using GAMS/CPLEX 12.6 solver. Furthermore, the battery lifetime model was included in the optimization model and fuel consumption was compared with other cases. Results show the slight increment in fuel consumption when the battery lifetime model was included.
Power system planning and operation offers multitudinous opportunities for optimization methods. In practice, these problems are generally large-scale, non-linear, subject to uncertainties, and combine both continuous...
详细信息
ISBN:
(纸本)9788393580132
Power system planning and operation offers multitudinous opportunities for optimization methods. In practice, these problems are generally large-scale, non-linear, subject to uncertainties, and combine both continuous and discrete variables. In the recent years, a number of complementary theoretical advances in addressing such problems have been obtained in the field of applied mathematics. The paper introduces a selection of these advances in the fields of non-convex optimization, in mixed-integerprogramming, and in optimization under uncertainty. The practical relevance of these developments for power systems planning and operation are discussed, and the opportunities for combining them, together with high-performance computing and big data infrastructures, as well as novel machine learning and randomized algorithms, are highlighted.
The manufacturers nowadays are forced to respond very quickly to changes in the market conditions. To adopt flexible mixed model assembly lines (MMAL) is a preferred way for manufacturers to improve competitiveness. M...
详细信息
ISBN:
(纸本)9783038352884
The manufacturers nowadays are forced to respond very quickly to changes in the market conditions. To adopt flexible mixed model assembly lines (MMAL) is a preferred way for manufacturers to improve competitiveness. Managing a mixed model assembly line involves two problems: assigning assembly tasks to stations (balancing problem) and determining the sequence of products at each station (sequencing problem). In order to solve both balancing and sequencing problem in MMAL simultaneously, an integrated mathematical model based on mixed integer programming (MIP) is developed to describe the problem. In the model, general type precedence relations and task duplications are considered. Due to the NP-hardness of the balancing and sequencing problem of MMAL, GA is designed to search the optimal solution. The efficiency of the GA is demonstrated by a case study.
Efforts to reduce power consumption in telecommunication networks follow in two mutually related directions - design of a more efficient equipment and development of energy-aware network control strategies and protoco...
详细信息
ISBN:
(纸本)9780983628392
Efforts to reduce power consumption in telecommunication networks follow in two mutually related directions - design of a more efficient equipment and development of energy-aware network control strategies and protocols. The paper presents a formulation of two-criteria traffic engineering problem, which takes advantage of energy saving capabilities in software routers. The first optimization criterion is the energy consumption, and the second one is the quality of service and service sustainability. Models and traffic engineering strategy were verified in laboratory experiments.
During the construction and especially water filling periods of Keban and Atatfirk dams in the Euphrates River Basin, there have been a series of high level political tensions among Turkey, Syria, and Iraq for the all...
详细信息
During the construction and especially water filling periods of Keban and Atatfirk dams in the Euphrates River Basin, there have been a series of high level political tensions among Turkey, Syria, and Iraq for the allocation of trans-boundary water resources. It has been claimed that those large investments not only contribute to those investing countries but also to those affected ones. This research measures the contributions and impacts of major investments on the basin to the riparian countries. And how spatial land use decisions on irrigated agricultural areas in rival basin countries are made by means of optimization techniques. The model application is based on with and without analyses for the selected group of dams, which are Keban, Karakaya, Ataturk, Ilisu, Tabqa, Haditha, and Mosul dams, Habbaniye Reservoir, and Urfa Tunnels. The mixed integer programming (MIP) based on the Inter Temporal Euphrates and Tigris River Basin Model (ITETRBM) is used as an optimization tool for the necessary analysis. The impacts are presented by countries and by the generated economic benefits, water withdrawals, coverage areas of irrigated agricultural land, cities feasibly supplied from the reservoirs. The results have shown that large reservoirs in Turkey provide extensive contribution to the basin countries especially during drought periods when all major reservoir investments are considered together. That can be considered as potential for coalition during drought periods instead of competition. (C) 2014 Elsevier Ltd. All rights reserved.
We propose an approach to reconstructing tree structures that evolve over time in 2D images and 3D image stacks such as neuronal axons or plant branches. Instead of reconstructing structures in each image independentl...
详细信息
ISBN:
(纸本)9781479951178
We propose an approach to reconstructing tree structures that evolve over time in 2D images and 3D image stacks such as neuronal axons or plant branches. Instead of reconstructing structures in each image independently, we do so for all images simultaneously to take advantage of temporal-consistency constraints. We show that this problem can be formulated as a Quadratic mixedinteger Program and solved efficiently. The outcome of our approach is a framework that provides substantial improvements in reconstructions over traditional single time-instance formulations. Furthermore, an added benefit of our approach is the ability to automatically detect places where significant changes have occurred over time, which is challenging when considering large amounts of data.
Wireless Sensor Networks (WSNs) comprising of battery-powered sensor nodes are being used in a wide range of applications. The feasibility of such applications is highly influenced by the longevity of these networks. ...
详细信息
ISBN:
(纸本)9781479923854
Wireless Sensor Networks (WSNs) comprising of battery-powered sensor nodes are being used in a wide range of applications. The feasibility of such applications is highly influenced by the longevity of these networks. In this work, we present a realistic WSN lifetime optimization framework where transmission power levels for both data and ACK packets are optimally selected (i.e., a complete link-layer handshaking cycle is modeled). Log-normal shadowing path loss model is employed to take into account the effects of path losses. We utilized the developed mixed integer programming (MIP) based optimization framework to investigate the impact of data packet length on WSN lifetime. To quantify the effects of data packet length on network lifetime we explored the parameter space consisting of the number of nodes and node deployment density. Our results show that the optimal data packet length is the maximum allowed length.
As the height of buildings grows, the demand of enhancing transportation capability in buildings has been increasing. If many elevator shafts are installed, its footprint occupies most floor space;floor space for acti...
详细信息
ISBN:
(纸本)9781479938407
As the height of buildings grows, the demand of enhancing transportation capability in buildings has been increasing. If many elevator shafts are installed, its footprint occupies most floor space;floor space for activities is reduced. Multicar elevator (MCE) systems are studied as one of the solutions for this problem. MCE systems can increase transportation capability without increasing floor space because MCE systems have several cars in each shaft. Optimization of car control and call assignment is necessary to control MCE systems safety and transport passengers rapidly. Our previous studies formulated the optimization problem as an integer Program (IP) and a mixedinteger Program (MIP). There, however, is a problem on the time for optimization. Therefore, a hybrid method of Constraint Program (CP) and MIP is proposed in this paper and is evaluated through computational experiments. The results show that the proposed method can transport passengers faster than existing methods.
暂无评论