• 한국항해항만학회지
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• 제33권4호
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• pp.271-275
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• 2009

A strategic decision making on location selection for product transportation includes many tangible and untangible factors. To choose the best locations is a difficult job in the sense that objectives usually conflict with each other. In this paper, we consider a multi stage multi criteria transshipment problem with different types of items to be transported from the sources to the destination points. For the optimization of the problem, a goal programming formulation will be presented in which the location selection for each product type will be determined under the multi objective criteria. In the study, we generalize the transshipment model with a variety of product types and finite number of different intermediate nodes between origins and destinations. For the selection of the criteria we selected the costs(fixed cost and transportation cost), location numbers, and unsatisfied demand for each type of products in multi stage transportation, which are the main goals in transshipment modelling problems. The related conditions are also modelled through linear formats.

• 대한전기학회논문지:전력기술부문A
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• 제53권10호
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• pp.542-549
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• 2004

The conventional fault location algorithms based on the travelling waves have an inherent problem. In cases of the close-up faults occurring near the relaying point and of the faults having zero degree inception angle of voltage signals, the conventional algorithms can not estimate an accurate fault distance. It is because the shapes of travelling waves are near sinusoidal in those cases. A new method solving this problem is presented in this paper. An FIR(Finite Impulse response) filter which makes high frequency components prominent and makes the power frequency component and dc-offset attenuated is used. With this method, the cross-correlation peak is to be very clear when a close-up fault or a fault having near zero-degree inception angle occurs. The cross-correlation peaks can be clearly distinguished and accurate fault location is practically possible consequently. A series of simulation studies using EMTP(Electromagnetic Transients Program) show that the proposed algorithm can calculate an accurate fault distance having maximum 2% or less error.

• 대한산업공학회지
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• 제28권4호
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• pp.425-434
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• 2002

Mobility of service users makes location update and paging (L/P) procedures indispensable features in mobile communication networks. Importance of optimizing the configuration of L/P areas has been increased by the growth of L/P related signaling. In this study, we deal with the L/P configuration which an LA (Location Area) may contain multiple PAs (Paging Areas). Given the network topology, L/P related parameters, and traffics generated by each cell, is provided the problem of finding optimal LA/PA configuration minimizing the amount of L/P related signaling. The optimization problem is solved using a simulated annealing, and detailed computational results are conducted to capture the effects of mobility, call arrival patterns and boundary crossing rate on the LA and PA configurations.

• 전기학회논문지
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• 제57권4호
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• pp.551-559
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• 2008

Increase in power consumption can cause a serious stability problem of an electric power system without construction of new power plants or transmission lines. Also, it can generate large power loss of the system. In costly and environmentally effective manner to avoid constructing the new infrastructures such as power plants and transmission lines, etc, the distributed generation(DG) has paid great attentions so far as a solution for the above problem. Selection of optimal location and size of the DG is the necessary process to maintain the stability and reliability of existing system effectively. However, the systematic and cardinal rule for this issue is still open question. In this paper, the method to determine optimal location of the DG is proposed by considering power loss when the DG is connected to an electric power grid. Also, optimal size of not only the corresponding single DG but also the multi-DGs is determined with the proposed systematic approach. The IEEE benchmark 30-bus test system is analyzed to evaluate the feasibility and effectiveness of the proposed method.

• International Journal of Computer Science & Network Security
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• 제24권1호
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• pp.45-51
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• 2024

The subject of navigation has drawn a large interest in the last few years. The navigation within a city is to find the path between two points, source location and destination location. In many cities, solving the routing problem is very essential as to find the route between different locations (starting location (source) and an ending location (destination)) in a fast and efficient way. This paper considers streets with diagonal streets. Such streets pose a problem in determining the directions of the route to be followed. The paper presents a solution for the path planning using the reconfigurable mesh (R-Mesh). R-Mesh is a parallel platform that has very fast solutions to many problems and can be deployed in moving vehicles and moving robots. This paper presents a solution that is very fast in computing the routes.

• 품질경영학회지
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• 제18권2호
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• pp.18-24
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• 1990

The location of inspection stations is a significant component of production systems. In this paper, a prototype expert system is designed for deciding the optimal location of inspection stations. The production system is defined as a single channel of n serial operation stations. The potential inspection station can be located after any of the operation stations. Nonconforming units are generated from a compound binomial distribution with known parameters at any given operation station. Traditionally Dynamic programming, Zero-one integer programming, or Non-linear programming techniques are used to solve this problem. However a problem with these techniques is that the computation time becomes prohibitively large when t be number of potential inspection stations are fifteen or more. An expert system has the potential to solve this problem using a rule-based system to determine the near optimal location of inspection stations. This prototype expert system is divided into a static database, a dynamic database and a knowledge base. Based on defined production systems, the sophisticated rules are generated by the simulator as a part of the knowledge base. A generate-and-test inference mechanism is utilized to search the solution space by applying appropriate symbolic and quantitative rules based on input data. The goal of the system is to determine the location of inspection stations while minimizing total cost.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.248-257
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• 2014

As observed in the recent war, suppression of enemy air defense operation is one of the major tactics, simultaneously conducted with high payoff target. Specifically, our air defense operation should be properly constructed, since the operating environment of our forces mostly consists with mountainous terrain, which makes detections of the enemy difficult. The effective arrangements of low altitude air defense radars can be suggested as a way of improving the detection capability of our forces. In this paper, we consider the location problem of low altitude air defense radar, and formulate it as an Integer Programming. Specifically, we surveyed the previous researches on facility location problems and applied two particularly relevant models(MCLP, MEXCLP) to our problem. The terrain factor was represented as demand points in the models. We verified the optimal radar locations for operational situations through simulation model which depicts simple battle field. In the simulation model, the performance of optimal radar locations are measured by the enemy detection rate. With a series of experiments, we may conclude that when locating low altitude air defense radars, it is important to consider the detection probability of radar. We expect that this finding may be helpful to make a more effective air defense plan.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.1-8
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• 2021

The subject of navigation has drawn a large interest in the last few years. Navigation problem (or path planning) finds the path between two points, source location and destination location. In smart cities, solving navigation problem is essential to all residents and visitors of such cities to guide them to move easily between locations. Also, the navigation problem is very important in case of moving robots that move around the city or part of it to get some certain tasks done such as delivering packages, delivering food, etc. In either case, solution to the navigation is essential. The core to navigation systems is the navigation algorithms they employ. Navigation algorithms can be classified into navigation algorithms that depend on maps and navigation without the use of maps. The map contains all available routes and its directions. In this proposal, we consider the first class. In this paper, we are interested in getting path planning solutions very fast. In doing so, we employ a parallel platform, Reconfigurable mesh (R-Mesh), to compute the path from source location to destination location. R-Mesh is a parallel platform that has very fast solutions to many problems and can be deployed in moving vehicles and moving robots. This paper presents two algorithms for path planning. The first assumes maps with linear streets. The second considers maps with branching streets. In both algorithms, the quality of the path is evaluated in terms of the length of the path and the number of turns in the path.

• Industrial Engineering and Management Systems
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• 제3권2호
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• pp.129-133
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• 2004

Studies on the optimal location of retail store have been made in case of no obstacle(Minagawa etal. 1999). This paper deals with the location problem of retail store considering obstacles (e.g. rivers, railways, highways, etc.) and obstacle-overcoming points (e.g. bridges, railway crossings, zebra crossings, overpasses, etc.). We assume that (1) commercial goods dealt here are typically convenience goods, (2) the population is granted as potential demand, (3) the apparent demand is a function of the maximum migration length and the distance from the store to customers, (4) the scale of a store is same in every place and (5) there is no competitor. First, we construct the basic model of customers' behavior considering obstacles and obstacle-overcoming points. Analyzing the two dimensional model, the arbitrary force attracting customers is represented as a height of a cone where the retail store is located on the center. Second, we formulate the total demand of customers and determine the optimal location that maximizes the total demand. Finally, the properties of the optimal location are investigated by simulation.

• 경영과학
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• 제26권3호
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• pp.23-35
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• 2009

This study deals with the location management in WCDMA (Wideband Code Division Multiple Access) networks. The new location management method is the one of the many techniques used to provide the packet switched (PS) services effectively in WCDMA networks. WCDMA introduces RA (routing area) for the PS services in addition to LA (location area) for the circuit switched (CS) services. WCDMA system also adopts the cooperative paging and the combined area update which are to decrease signaling traffic using the PS network resources for the CS services. Considering the characteristics of the WCDMA networks, this study formulate into the mathematical programming problem for the location management. Rather than the existing researches which consider the single MSC/SGSN networks, we deal with the multi MSC/SGSN networks, where both MSC area and SGSN area should be determined as well. Fairness between traffic loads of MSC/SGSN and the system cost incurred to MSC/SGSN are also incorporated into our model, which make the model more realistic. We propose greedy algorithms for the problems, which consists of the merger of two neighboring areas and the movement of an area. Extensive experiment has been done based on the realistic problem examples. Followed by the analysis of parameter effect on the final solutions and the quality of final solutions obtained by our greedy algorithms. Our proposed model and analysis result can be used to determine WCDMA system areas and to predict the system performance measures by the determination.