• Journal of the Korea Society for Simulation
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• v.20 no.2
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• pp.1-10
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• 2011

In queueing network analysis, arrival processes are usually modeled as renewal processes by matching mean and variance. The renewal approximation simplifies the analysis and provides reasonably good estimate for the performance measures of the queueing systems under moderate conditions. However, high variability in arrival process or in service process requires more sophisticated approximation procedures for the variability parameter of departure/arrival processes. In this paper, we propose an heuristic approach to refine Whitt's variability function with the k-interval squared coefficient of variation also known as the index of dispersion for intervals(IDI). Regression analysis is used to establish an empirical relationships between the IDI of arrival process and the IDI of departure process of a queueing system.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2004.11a
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• pp.413-417
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• 2004

The important goal of urban renewal is not to reform only Physical environment but to improve people' life quality. people who have been lived in urban renewal area are grouped to owner and tenant. owner of land or house has substituent right but tenant has only house-moving money or rental house by urban renewal. But rental house condition is not good to tenant because tenant has large family, low-income and low grade and it is essential to provide rental house for low-income class and it is worth to analyze tenant house problem The purpose of this study is to analyze the problems of public rental house and to presents solutions. The study was done in following process. First, the literatures on this subject were investigated to seek the problems of public rental house. Second, Survey were done on the staff, who works in the cooperative housing redevelopment and whose jobs are officer, consultant, real estate introducer and designer, to seek problems and solution of public rntal house. survey which is made by three group. one group is made by people who already lived in tenant APT, second group is made by people who are waiting for moving in tenant APT. Third group is made by specialist who has many experience-more than 3years- to urban renewal. Third, the Correlation Analysis was used to analyze the relation between the Area and dwelling satisfaction. Fourth, tenant policy' altenative is presented to solve tenant APT' problem which is analyzed by this study The results are as follows : First, tenant APT' size Which is regulated to 30-$45m^{2}$ is enlarged to more than $45m^{2}$ because tenant family is made up averagely of 4.8 persons. Second, tenant APT' rental cost is reduced to 100 thousand won. Third tenant APT' arrangement is divided from owner because tenant and owner want to live in group by group. Fourth, tenant house type is changed to various house type because tenant is not familiar with APT

• Land and Housing Review
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• v.1 no.1
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• pp.9-17
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• 2010

Due to the variety of processes that are mainly influenced by the modification of law and regulations, it is difficult to propose a formal procedure of urban renewal projects. In addition, conflicts among various participants and stake-holders have made urban renewal difficult to manage. Needs for new systems to support management of this type of projects have been raised. This system should enable users to manage program aspects as well as projects given that the urban renewal consists of several projects. According to analysis of current context, the requirements of the system are classified as follows: a method to create flexible systems to cope with various process; functions to provide data on cost and schedule; user-friendly visualized tools enhancing understand of non-experts or less-experienced participants. This paper summarizes the background, requirements, concept and model of the system. Currently, prototype systems have been developed. Regarding outputs presented so far, potential benefits of the system are presented as well.

• IE interfaces
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• v.25 no.1
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• pp.127-133
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• 2012

This paper considers the preventive maintenance scheduling problem of the cluster tool which is one of the most important manufacturing equipments in the next-generation semiconductor production environment. We define a random process that expresses the successive amount of chemicals accumulating inside the tool. Based on the renewal theory, we find the expected value and probability distribution of the time that the amount of accumulated chemicals exceeds a predetermined level. For a given probability that the accumulated chemicals exceeds the predetermined level we present a method to obtain the number of chamber operations to perform the preventive maintenance of that chamber. In addition, a method to get the preventive maintenance schedule for the whole cluster tool is presented. A numerical example is provided to illustrate our method.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.49-64
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• 2000

We consider a system whose inherent life follows an Erlang distribution, which is subject to two heterogeneous random shocks. Minor shocks arrive according to a renewal process and each causes the system to fail independently with a certain probability. A major shock whose interarrival times follow an Erlang distribution causes the system to fail with probability one. The Laplace transform of the distribution of the time to system failure is derived in a functional form of the Laplace transform of the interarrival time distribution of minor shocks. An algorithm is given for the computation of the moments of the time to system failure.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1616-1625
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• 2019

Measuring occurrence times of random events, aimed to determine the statistical properties of the governing stochastic process, is a basic topic in science and engineering, and has been the subject of numerous mathematical modeling approaches. Often, true statistical properties deviate from measured properties due to the so called dead time phenomenon, where for a certain time period following detection, the detection system is not operational. Understanding the dead time effect is especially important in radiation measurements, often characterized by high count rates and a non-reducible detector dead time (originating in the physics of particle detection). The effect of dead time can be interpreted as a suitable rarefied sequence of the original time sequence. This paper provides a limit theorem for a high rate (diffusion-scale) counter with extendable (Type II) dead time, where the underlying counting process is a renewal process with finite second moment for the inter-event distribution. The results are very general, in the sense that they refer to a general inter arrival time and a random dead time with general distribution. Following the theoretical results, we will demonstrate the applicability of the results in three applications: serially connected components, multiplicity counting and measurements of aerosol spatial distribution.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• Journal of Korean Society of Rural Planning
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• v.2 no.1
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• pp.57-68
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• 1996

Village Renewal(Dorferneuerung) Policy Program in Germany, directly originated from Rural Beutification Movement between mid 18C and mid 19C, has several characteristics as follows. First, we can find out the planned approach in land use and settlement reorganization of Pillage Renewal Program. There are three ways to designate the planning area of the village rearrangement project in countryside. One is to designate the detailed B-plan district by urban plan for the village over some size defined legally. Another is to have a living space of settlement be contained in land allotment project area. In this case, residential areas of several villages related to agricultural land consolidation should be simultaneously designated as the project area. The last is only for the built environment focused on the living space. Second, the emphasis in German village encouragement program can be made on the integral approach through which sets of policy programs of the land allotment, the living environment improvement, the physical landscape management and the cultural resources conservation are intensively implemented together. Third, the bottom-up and community participation approach can be greatly stressed on the planning and implementation process, Community participation, subsidy application to local government by residents themselves, community consensus on architectural style and outdoor spatial form, etc. have been recognized as an effective strategy to accomplish the task of village activity promotion.

• Journal of Korean Society of Rural Planning
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• v.15 no.3
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• pp.23-32
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• 2009

The purpose of this research was to evaluate rural housing environment through evaluation of the two parties, public officials, the interest group and residents, the beneficiaries surveying general understanding and measuring difference in understanding between public officials and residents. Through the difference in understanding, this study was to propose effective promotion method and desirable direction of rural housing environment. For progress hereafter, by seeking active involvement of residents, this study proposed possible renewal plan of residential environment. Process of this study was first, research documents to examine several rural housing environment related promotions, and several analysis techniques like principal component analysis, multiple regression analysis used to understand different ideas Opinion of Public Officials and Inhabitants. Then take surveys of residents living in renewal zone, and surveys of public officials of borough, which already performed renewal projects to evaluate comprehensively as either residents' or administrators' view.

• Journal of Korea Society of Digital Industry and Information Management
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• v.20 no.1
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• pp.133-147
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• 2024

In this study, we examine the components and characteristics of channel brands, the renewal process of channel brands, and the competitiveness of SBS Subusu News and MBC 14F, online channels of Korea's leading terrestrial broadcasting company. We conducted in-depth interviews with staffs YouTube news channels such as Subusu News and 14F. First, examining the brand components and characteristics of SBS's Subusu News and MBC's 14F vertical channel, Subs News maintained its direction through the renewal of the logo type, graphic characterization, emoticon production, and campaign design production. 14F focused on brand renewal of the logo type and modification of thumbnail design to reveal the identity of the channel brand. Subusu News and 14F have achieved success through a spin-off approach that considers content relevance, expanding their brand extension. As a result of analyzing the competitiveness of the channel brand, Subusu News maintained its identity as a combination of B-class sensibility and journalism, while 14F positioned itself as a channel that delivers useful information content.