• Industrial Engineering and Management Systems
• /
• v.3 no.2
• /
• pp.92-99
• /
• 2004

We consider the ATM switching node location problem (ANLP). In this problem, there are two kinds of facilities, hub facilities and remote facilities, with different capacities and installation costs. We are given a set of customers with each demand requirements, a set of candidate installation sites of facilities, and connection costs between facilities. We need to determine the locations to place facilities, the number of facilities for each selected location, the set of customers who are connected to each installed hub via installed remote facilities with minimum cost, while satisfying demand requirements of each customer. We formulate this problem as a general integer programming problem and solve it to optimality. In this paper, we present a preprocessing procedure to tighten the formulation and develop a branch-and-price algorithm. In the algorithm, we consider the integer knapsack problem as the column generation problem. Computational experiments show that the algorithm gives optimal solutions in a reasonable time.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.24 no.3
• /
• pp.93-107
• /
• 1999

We consider the development of an integer programming model and algorithm for the ATM switching node location problem. There are two kinds of facilities, hub facilities and remote facilities, with different capacities and installation costs. Each customer needs to be connected to one or more hub facilities via remote facilities, where the hub(remote) facilities need to be installed at the same candidate installation site of hub(remote) facility. We are given a set of customers with each demand requirements, a set of candidate installation sites of facilities, and connection costs between facilities, We need to determine the locations to place facilities, the number of facilities for each selected location, the set of customers who are connected to each installed hub facilities via installed remote facilities with minimum costs, while satisfying demand requirements of each customer. We formulate this problem as a general integer programming problem and solve it to optimality. In this paper, we develop a branch-and-cut algorithm with path variables. In the algorithm, we consider the integer knapsack polytope and derive valid inequalities. Computational experiments show that the algorithm works well in the real world situation. The results of this research can be used to develop optimization algorithms to solve capacitated facility location problems.

• Journal of Astronomy and Space Sciences
• /
• v.5 no.1
• /
• pp.9-18
• /
• 1988

Gamma Cassiopeae has been observe at Yonsei University Observatory(YUO) for 31 nights in the period 1983-1987 and a total of 312 UBV observations(104 in each colour) was secured. Light curves of ${\gamma}$ Cas in V, B-V, and U-B have been constructed with the YUO data; among them we present selected light curves of 5 different long nights. Discussed are the general photometric behaviour of ${\gamma}$ Cas, especially in connection with B-V changes, V/R variations of $H\alpha$ and H$\beta$, and high velocity narrow component(hvnc) exhibited in the far UV. Six spectral image sets of $\varepsilon$Per archived on IUE satellite are reduced and their line profiles in C IV and Si IV resonance lines are analyzed to find out any change, but the evidence is unlikely.

• Journal of Korea Technology Innovation Society
• /
• v.3 no.3
• /
• pp.102-112
• /
• 2000

The authors of this paper chose the delphi methods to investigate into several areas to understand where the pressures for ATM equipments will emerge in the prescribed time horizon of 1999 to 2010- a period just beyond the current manufacturing and deployment schedules of most companies. The areas studied are the office buildings and interoffice connectivity as well as switches, and finally transmission facilities. This paper is matched into these areas with the results of a Delphi study of 14 respondents from the common carriers like Korea Telecom and national institutions like ETRI. The investigators calculated the average answer for each question and presents the questionnaires for a second round to individuals who had responded to the first round of questioning. As a result of this paper, the authors reached some conclusions regarding what item will be predominant in each of the areas studied as well as the promoters and barriers for ATM deployment and some suggestions are provided for corporate managers and policy makers. This Delphi study did not provide a strong and uniform forecast that ATM would dominate the marketplace in the early years of next millenium, as many had anticipated. Whether it is in he area of office connection, enterprise backbone, switches and transmission facilities, respondents predicted the patterns which indicate a movement toward higher-bandwidth connectivity, although not necessarily provided with ATM networks. A general pattern is that the predictions for ATM deployment in each of the areas were strong from the year 1999 to 2010.

• Korean Institute of Interior Design Journal
• /
• v.17 no.6
• /
• pp.178-187
• /
• 2008

This study aims to analyze general features and forms of spatial structure of major space in museums and for the scope of this study, set up major space and the surrounding areas structured around major space and for the target of analysis, selected 10 museums of overseas examples from 19th century to 2006. And this study on focus, on the circulation structure and visual structure will be analyzed in qualitative method by focusing on the floor plan and section structures; deepening process of analysis, visual structure will turn into numerical value to analyze the spatial structure of the major space. The results of this study are as follow. First, vertical elements should be critically considered in a circulation plan for functional performance of dimensional circulation distribution in a major space. Second, a plan by location of vertical and horizontal moving elements related to a major space affects a circulation relation more than a connection type between a major space and an exhibition area. Third, it could be categorized into 4 types by considering the features of spatial structure followed by connecting relationship between areas. Fourth, comparable figures were drawn out among large space and surrounding areas but it couldn't draw out types.

• Journal of the Korean Society of Safety
• /
• v.32 no.3
• /
• pp.66-73
• /
• 2017

This study examined the structural behavior of bracket scaffolds reflecting the influence of bracket's deflection. Even though the supporting condition of bracket scaffolds is different to that of general earth-supported scaffolds, there is no clear standards about the installation of bracket scaffolds. To compare the structural behaviors of the earth-supported scaffolds without settlements in columns and those of bracket scaffolds installed on the bracket structure, the finite element analysis was performed. The results show that the differential settlement between the scaffold columns installed on the bracket was occurred due to the deflection of the bracket. The differential settlement gave birth to remarkable secondary stress to the scaffold columns. It is resonable to locate all scaffold columns on the brackets, and if unavoidable situation is faced at a site, the horizontal members should not placed alone without columns on the brackets. Moreover, the structural analysis should be performed to ensure structural safety of bracket scaffolds before installation. In addition, the location of wall connection to the structures is recommended to the scaffolds columns installed on the brackets.

• Journal of the Korean Mathematical Society
• /
• v.54 no.2
• /
• pp.461-477
• /
• 2017

A dual substructuring method with a penalty term was introduced in the previous works by the authors, which is a variant of the FETI-DP method. The proposed method imposes the continuity not only by using Lagrange multipliers but also by adding a penalty term which consists of a positive penalty parameter ${\eta}$ and a measure of the jump across the interface. Due to the penalty term, the proposed iterative method has a better convergence property than the standard FETI-DP method in the sense that the condition number of the resulting dual problem is bounded by a constant independent of the subdomain size and the mesh size. In this paper, a further study for a dual iterative substructuring method with a penalty term is discussed in terms of its convergence analysis. We provide an improved estimate of the condition number which shows the relationship between the condition number and ${\eta}$ as well as a close spectral connection of the proposed method with the FETI-DP method. As a result, a choice of a moderately small penalty parameter is guaranteed.

• Structural Engineering and Mechanics
• /
• v.61 no.6
• /
• pp.737-746
• /
• 2017

The touch down zone (TDZ) and top connection point of the vessel are most critical part of fatigue damage in the steel catenary riser (SCR). In general, the linear soil model has been used to evaluate fatigue performance of SCRs because it gives conservative results in the TDZ. However, the conservative linear soil model shows the limitation to accommodate real behavior in the TDZ as water depth is increased. Therefore, the riser behavior on soft clay seabed is investigated using a nonlinear soil model through time domain approach in this study. The numerical analysis considering various important parameters of the nonlinear soil model such as shear strength at mudline, shear strength gradient and suction resistance force is conducted to check the adoptability and applicability of nonlinear soil model for SCR design.

• Journal of the Korean Institute of Navigation
• /
• v.19 no.4
• /
• pp.103-121
• /
• 1995

As Daniel Bell says, that modern society is an information society. In contrast to earlier days, modern society has placed a high value on information and knowledge. Therefore, modern civilization depends largely on information and knowledged, which is the most valuable sources of all intelligence activities. By coordinating a large number of human action, the information creates a powerful social tool. It combines its personnel with its resources and new materials at various level. At the same time, It continually evaluates how well it is performing and tries to adjust itself accordingly in order to achieve social goals. As we shall see, all this allows information to sew the various needs of society. In connection with above mentioned problem consciousness, the study is designed to sew the following purposes. As its title indicates, and perhaps most significant. This study is to review and reinterpret the existing literature on local telecommunication system, networks, and policy direction in order to arrive at a somewhat more general approach to understanding them. In local telecommunications service, the service exploitation and promotion and database development must be accomplished by establishing local telecommunications. If we develop local telecommunications toward the progressing direction, we would dissolve the regional information disparity and could also make the local policy suited for high-intelligence society. It is true of any science that knowledge is never complete. It is also true of a science that knowledge should grow, through systematic reexamination of the body of findings. There are certainly true of this study on the developmental direction for local telecommunication system.

• Proceedings of the KIEE Conference
• /
• 2006.05a
• /
• pp.48-50
• /
• 2006

SC(Static Condenser) in KEPCO is used in voltage control and power factor compensation. Currently KEPCO uses SC to 154kv 50MVA and 23kv SMVA. It is not important in old days because a SC bank accident has no effect on power system. But we are interested in the SC bank for power quality in these days. The SC Bank has a reactor and a condenser using series connection. It is operated in critical point for resonance circuit normally. Therefore the SC bank has a small reliability against other Power instruments. If a 4th harmonic frequency as a resonance frequency is supplied in system, the condenser is damaged because of a resonance current. And a trip and a closing for CB(Circuit Breaker) in many times will have a big influence of SC bank destruction. General OCR(Over Current Relay) observing SC bank is not useful for this protection We think that protection relay must be have the SC bank characteristics. A solution for this problem is active Power, resonance frequency and impedance.