• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.614-623
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• 2016

Grid(pipe network) design is an important element of Smart Water Grid, which essential to estimate hydraulic parameters such as the pressure, friction factor, friction velocity, head loss and energy slope. Especially, friction velocity in a grid is an important factor in conjunction with energy gradient, friction coefficient, pressure and head loss. However, accurate estimation friction head loss, friction velocity and friction factor are very difficult. The empirical friction factor is still estimated by using theory and equation which were developed one hundred years ago. Therefore, in this paper, new equation from maximum velocity and friction velocity is developed by using integration relationship between Darcy-Weisbach's friction head loss equation and Schlichting equation and regression analysis. To prove the developed equation, smooth pipe data areis used. Proposed equation shows high accuracy compared to observed data. Study results are expected to be used in stability improvements and design in a grid.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.12
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• pp.568-575
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• 2008

Server consolidation by sever virtualization can make one physical machine(PM) to run several virtual machines simultaneously. Although It is attractive in cost, it has complex workload behaviors. For that reason, efficient resource management method is required. Dynamic relocation of virtual machine(VM)[3,4] by live migration[1,2] is one of resource management methods. We proposed SCOA(Server Consolidation Optimizing Algorithm) : a fine-grained load balancing mechanism worked on this dynamic relocation mechanism. We could obtain accurate resource distribution information through pointed physical machines on multi dimensional resource usage coordination, so we could maintain more balanced resource state. In this paper, we show the effectiveness of our algorithm by comparison of experimental results between SCOA and sandpiper[3] by software simulation.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10683-10690
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• 2015

The big gap between efficacy of population level prevention and expectations due to heterogeneity and complexity of cancer etiologic factors calls for selective yet personalized interventions based on effective risk assessment. This paper documents our research protocol aimed at refining and validating a two-stage and web-based cancer risk assessment tool, from a tentative one in use by an ongoing project, capable of identifying individuals at elevated risk for one or more types of the 80% leading cancers in rural China with adequate sensitivity and specificity and featuring low cost, easy application and cultural and technical sensitivity for farmers and village doctors. The protocol adopted a modified population-based case control design using 72, 000 non-patients as controls, 2, 200 cancer patients as cases, and another 600 patients as cases for external validation. Factors taken into account comprised 8 domains including diet and nutrition, risk behaviors, family history, precancerous diseases, related medical procedures, exposure to environment hazards, mood and feelings, physical activities and anthropologic and biologic factors. Modeling stresses explored various methodologies like empirical analysis, logistic regression, neuro-network analysis, decision theory and both internal and external validation using concordance statistics, predictive values, etc..

• Korean Journal of Human Ecology
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• v.18 no.4
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• pp.809-824
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• 2009

The purpose of this study is to examine the contents and concept of program for healthy family and provide job opportunity and competency of healthy family supporter. For this research, participants are 51 healthy family supporters as a middle manager. Data were obtained through the survey using a questionnaire developed by the ministry of women and family and headquarter of healthy family support centers in 2007. The research process consists of two parts. One is to suggest their jobs and requirements, the other is to offer their core competency and area for improvement. First, the jobs of healthy family supporters as a middle manager are the generalization of team's work including the planning, management and coordination, training for the staff, and network of social resources. They recognized the planning and management of healthy family support center's goal and course as a strategic job. The requirements for the performance of their duties are having a bachelor's or a master's degree, career more than for 3 years, and a certificate of qualification of healthy family supporters, social worker and family counselor. Second, their competencies are the understanding of education of family life, theory of family counselling, the planning and valuation of program for healthy family, understanding for the variegated family, management of organization, networking with resources, ability of documentation, ability of persuasion and negotiation, management of time, sociality, communication skill, solving the problem, positiveness, cooperative spirit and so on.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.21-28
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• 2008

This study deals with the participatory design process of renovating a children's park. The process should proceed with two major elements. Firstly, the children's park should be designed from the perspective of children. Secondly, it should be designed in consideration of the context of the community. This study is divided into two parts. First is the review of theory concerning the meaning and roles of the children's park as a community space, the importance of children's participation in the design and the participatory method of the children. The second is the case study. The site for the case study is Ssial Park in Nowon-Gu, Seoul. The entire process of the case study is with community participation, from identifying the park's problems to the actual construction. At every step, through the participatory programs, the community participates in the decision making. In addition, mutual understanding among participants is pursued through diverse means of communication. The following results of the case study were found. Firstly, diverse participatory programs and the active trial to enable the community to communicate contribute to the sense of ownership and responsibility concerning the park Secondly, the community can negotiate the differences in opinions without needing the help of experts. Of course, there are limits in the case study, such as the fact that the community organization, which is the core of communication and maintenance concerning the park, is not organized through the process of a case study. Another is that more diverse methods, which inform all community members of the participatory process, should have been used.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.842-854
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• 2001

Today\`s first generation shopping agent is limited to comparing merchant offerings usually on price instead of their full range of attributes. Even in the full range comparison, there is not a good model which considers the overall features in the negotiation process. Therefore, the negotiation model needs to be extended to include negotiations over the more attributes. In this paper, we propose a negotiation model in the agent-mediated electronic commerce to negotiate over prices, product features, warranties and service policies based on utility theory and simple heuristics. We will describe a prototype agent-mediated electronic commerce framework called Pmart. This framework provides the software reuse and the extensibility based on the object-oriented technology. It is implemented on Windows-based platforms using Java and CORBA for the network transparency and platform independence.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.6
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• pp.296-305
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• 2005

TCP/IP, the most popular communication protocol, is processed on a host CPU in traditional computer systems and this imposes enormous loads on the host CPU. Recently TCP/IP Offload Engine (TOE) technology, which processes TCP/IP on a network adapter instead of the host CPU, becomes an important way to solve the problem. In this paper we analysed the structure of a TCP/IP protocol stack in the Linux operating system and important factors, which cause a lot of loads on the host CPU, by measuring the time spent on processing each function in the protocol stack. Based on these analyses, we propose a Hybrid TOE architecture, in which functions imposing much loads on the host CPU are implemented using hardware and other functions are implemented using software.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.654-662
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• 2005

Mobile portable devices for wireless network solely depend on a limited battery power. Therefore, we need to design for wireless communication protocols with an energy efficiency. TCP-Westwood is one of the most important approaches on TCP performance improvement in wireless environments that estimates the available bandwidth by using the sampling mechanism. The advantage is that data can be transmitted efficiently using the estimation of available bandwidth. However, when the sender with TCP-Westwood is in a wireless environment, it does not consider of the sampling mechanism operation. In this thesis, a new energy saving transport protocol, called E2TP(Energy Efficient Transport Protocol), is proposed to solve problems which occur when the sender with TCP-Westwood is in a wireless environment. Also, when there are packet loss while doing frequent link error in a wireless environment, E2TP provides the instantaneous segment size adjustment for a more efficient data retransmission. The simulation result proves that the proposed E2TP has better performance in energy efficiency and throughput than both TCP and TCP-Westwood.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1135-1144
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• 1999

본 논문에서 우리는 셀룰러 통신 시스템을 위한 위치갱신과 위치질의 비용을 줄일 수 있는 새로운 위치관리 기법을 제안한다. 위치갱신 및 위치질의 비용을 줄이기 위하여, 제안한 위치관리 기법은 사용자 지역성을 사용한다. 사용자 지역성은 이동 지역성과 호 지역성으로 이루어진다. 이동 지역성을 갖는 이동단말들을 위한 위치갱신은 지역 PVLR(Proxy-Visitor Location Register) 갱신에 의해 위치갱신 비용을 줄일 수 있다. 호 지역성을 갖는 이동단말들을 위한 위치질의는 지역 PVLR 질의에 의해 위치질의 비용을 줄일 수 있다. 분석 모델을 통하여, 제안한 기법의 성능 분석과 IS-41 표준과 제안 기법과의 성능을 비교한다. 사용된 비교 척도는 네트워크 비용, 데이타베이스 비용 그리고 호 설정 지연이다. 이들 모든 척도들에 대해서, 제안 기법이 IS-41 표준에서 정의된 위치관리 기법보다 더 좋은 성능을 보인다. 또한 비교 결과는 CMR(Call-to-Mobility Ratio)에 상관없이 제안 기법이 IS-41 기법보다 성능이 좋음을 보여준다. Abstract In this paper, we propose a new location management scheme for cellular communication systems with the goal of reducing both location update and query cost. In order to reduce both location update and query cost, the proposed scheme uses user locality. User locality consists of movement and call locality. For mobile terminals with movement locality, location update cost is reduced by local PVLR(Proxy-Visitor Location Register) update. Location query cost is reduced by local PVLR query for mobile terminals with call locality. Through analytical models, we analyze the performance of the proposed scheme and compare it with that of the IS-41 scheme. The measures of comparison used are the network cost, the database cost, and the call set up delay. For all these measures, the proposed scheme performs better than the location management scheme defined in the IS-41 standard. Result comparison also shows that the our scheme performs better than the IS-41 scheme, regardless of CMR(Call-to-Mobility Ratio).

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1126-1134
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• 1999

최근 다양한 멀티미디어 서비스를 지원하기 위한 통신망 관리와 서비스 관리가 통합된 개방형 정보 통신망의 구조가 요구되고 있다. 이러한 구조를 기반으로, TINA-C(Tele-communications Information Networking Architecture-Consortium)에서는 분산 환경에서 분산 어플리케이션 객체들에 대한 복잡한 서비스 및 관리 인터페이스들을 간결하도록 객체그룹의 개념을 정의하고 있다. 이러한 환경 속에서 트레이딩 서비스는 통신 서비스를 제공하는 객체그룹간의 상호작용을 지원하는데 매우 중요하다.따라서, 본 논문에서는 객체그룹간의 상호접속을 지원할 수 있는 트레이딩 기능과 이들 트레이더들간의 연동을 위한 트레이더 연합 모델을 제시하고자 한다. 이를 위해 우리는 트레이더의 중개자로서 Cooperator를 설계하여 기존의 트레이더와 연동시켰다. 이러한 결과로서 우리의 새로운 트레이더 연합 모델에서 Cooperator는 객체그룹간의 상호접속에서 객체들의 접속 권한의 체크 기능과 기존의 트레이더 연합모델의 문제점인 트레이더들간의 단 방향 연결문제를 보완하여 양방향 연결 기능을 갖도록 하였다. 끝으로, 이러한 해결 과정을 보이기 위해 트레이더와 Cooperator들로 이루어진 본 연합모델에서 분산 객체그룹간의 상호접속 절차과정과 사건 추적 다이어그램을 보였다.Abstract Recently, the open networking architecture is required to support various multimedia services as integrated functions of network management and service management. Based on this architecture, TINA-C defines an object group concept for simplifying complex management and service interfaces, when distributed application is executed in distributed environments. Within the support environment the trading service is an important of the interacting object groups which provide a telecommunication service.Hence, we suggest the trader federation model for supporting interconnections between object groups and among existing traders by using the cooperator we designed, as an intermediator among traders. Our cooperator has functions for checking access rights of objects in object groups, and for providing bidirectional linkage among traders. Up to now, the existing trader federation models have a single directional linkage for interactions among traders. Finally, we showed the interface procedure and the event trace diagram of distributed object groups using our model consisted of traders and the cooperators.