• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.567-569
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• 1998

기업내 분산 이기종 시스템들을 통합하는 문제를 해결하기 위해 객체지향개발방법론을 이용해 분석 및 설계를 진행하고 그 결과를 개체 기술을 이용해 구현하려는 노력이 활발하게 진행되고 있다. 그러나 아직까지 객체지향 분석 및 설계에 대한 이해와 경험의 부족으로 인해 실제 업무에서 사용될 수 있는 시스템보다 실험적인 시스템의 개발에만 적용되고 있다. 본 논문에서는 주문자가 공장에 주문한 제품에 대한 생산 및 조달의 현재 상황을 주문자 및 공장에서 실시간으로 모니터링 할 수 있는 실제적인 시스템의 개발을 위한 분석 및 설계에 초점을 맞추고 있다. 이를 위해 UML 방법론을 선택하고 UML을 지원하는 CASE 도구를 이용해 분석 및 설계를 수행했으며, JAVA와 CORBA 기반의 분산 객체 기술을 이용한 시스템 구현을 위해 OMG IDL을 산출물로 획득했다. 본 논문을 통하여 제시된 객체지향 분석 및 설계의 예는 객체지향 개발 방법론을 이용해 분산 객체 시스템을 개발하고자 하는 개발자들에게는 방법론의 안정성 및 실무 적용 경험에 대한 정보를 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.146-147
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• 2013

소셜 미디어와 스마트폰의 확산으로 인터넷상의 사용자간 교류되는 정보의 양이 대폭 늘어남에 따라 대규모의 데이터를 처리해야할 필요성이 높아졌다. 이러한 빅데이터는 뉴스, 소셜미디어, 웹사이트 등의 다양한 분산 서버에서 발생한다. 증권정보를 분석하기 위해서도 실시간으로 발생되는 거래량, 시가와 더불어 상장회사의 공시 정보 등의 데이터를 여러 분산된 서버에서 데이터를 가져와야 한다. 기존의 빅데이터 분석기법은 각 분산된 서버로부터 가져온 데이터가 동일한 신뢰성을 가지고 있다고 가정하고 분석을 한다. 이는 부문별한 정보를 포함한 데이터를 효율적으로 분석하지 못하는 한계를 지니고 있다. 본 논문에서는 가져오는 데이터에 신뢰성 가중치를 부여하여 신뢰성 있는 증권정보 분석을 가능하게 한다.

• The KIPS Transactions:PartA
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• v.15A no.4
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• pp.199-210
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• 2008

A Clustering based wireless internet proxy server needs a layer-7 load balancer with URL hashing methods to reduce the total storage space for servers. Layer-4 load balancer located in front of server cluster is to distribute client requests to the servers with the same contents at transport layer, such as TCP or UDP, without looking at the content of the request. Layer-7 load balancer located in front of server cluster is to parse client requests in application layer and distribute them to servers based on different types of request contents. Layer 7 load balancer allows servers to have different contents in an exclusive way so that it can minimize the total storage space for servers and improve overall cluster performance. However, its scalability is limited due to the high overhead of parsing requests in application layer as different from layer-4 load balancer. In order to overcome its scalability limitation, in this paper, we propose a distributed layer-7 load balancer by replacing a single layer-7 load balancer in the conventional scheme by a single layer-4 load balancer located in front of server cluster and a set of layer-7 load balancers located at server cluster. In a clustering based wireless internet proxy server, we implemented the conventional scheme by using KTCPVS(Kernel TCP Virtual Server), a linux based layer-7 load balancer. Also, we implemented the proposed scheme by using IPVS(IP Virtual Server), a linux-based layer-4 load balancer, installing KTCPVS in each server, and making them work together. We performed experiments using 16 PCs. Experimental results show scalability and high performance of the proposed scheme, as the number of servers grows, compared to the conventional scheme.

• Spatial Information Research
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• v.8 no.2
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• pp.243-255
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• 2000

The spatial distribution characteristics and patterns of geographic features in space can be understood through a variety of analysis techniques. The scale is one of most important factors in spatial analysis techniques. This study is aimed at identifying the characteristics of spatial data with a coarser spatial resolution and finding procedures for spatial resolution in operational scale. To achieve these objectives, this study selected LANSAT TM imagery for Sunchon Bay, a coastal wetland for a study site, applied the indices for representing scale characteristics with resolution, and compared those indices. Local variance and fractal dimension developed by previous studies were applied to measure the textual characteristics. In this study, Moran s I was applied to measure spatial pattern change of variance data which were generated from the process of coarser resolution. Drawing upon the Moran s I of variancedata was optimum technique for analysing spatial structure than those of previous studies (local variance and fractal dimension). When the variance data represents maximum Moran´s I at certainly resolution, spatial data reveals maximum change at that resolution. The optimum resolution for spatial data can be explored by applying these results.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.19-24
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• 2021

In this paper, we study performance factor of machine learning in the distributed environment using Apache Spark and presents an efficient distributed processing method through experiments. This work firstly presents performance factor when performing machine learning in a distributed cluster by classifying cluster performance, data size, and configuration of spark engine. In addition, performance study of regression analysis using Spark MLlib running on the Hadoop cluster is performed while changing the configuration of the node and the Spark Executor. As a result of the experiment, it was confirmed that the effective number of executors was affected by the number of data blocks, but depending on the cluster size, the maximum and minimum values were limited by the number of cores and the number of worker nodes, respectively.

• Journal of Information Technology Application
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• v.2 no.1
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• pp.139-160
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• 2000

This paper suggests a technique for evaluating cognitive process when a working group performs its group tasks. First, it review a theory of distributed cognition which provides a theoretical background for investigating group's cognitive process. Then, it presents a procedure for DGOMS(Distributed GOMS) evaluation which is an extension from GOMS. GOMS is an analytica evalutation technique that has been used at the individual level. DGOMS analyzes task completion time and compares workload among group members on the basis of each member's task execution time, communication time, and cognitive workload. DGOMS can be applied to a situation where a group of people are working together for a common goal using a technical subsystem such as information systems.

• Review of KIISC
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• v.7 no.3
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• pp.131-142
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• 1997

본 고에서는 현재 분산환경에서의 인증 메커니즘으로 널리 고려되고 있는 Kerberos 인증 방식의 초기 버전인 Kerberos V.4 와 개선된 버전인 V.5 그리고 공개키 암호를 도입하여 Kerberos 를 개선한 Yaksha 인증 메카니즘을 소개하고자 한다. 또한 분산 환경에서의 대표적인 두 방식을 비교 분석하여 보았다.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.16-23
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• 2013

The effects of dispersion coefficient of dispersion compensating fiber (DCF) and residual dispersion per span (RDPS) on in the dispersion managed optical links for compensating the distorted 960 Gbps wavelength division multiplexd (WDM) signals due to group velocity dispersion (GVD) and optical nonlinear effects of single mode fiber (SMF) are investigated. It is confirmed that optimal net residual dispersion (NRD), which greatly affects compensating for optical signals, should be induced under the large launch power condition, irrelevant on the considered dispersion coefficient of DCF and RDPS. It is also confirmed that system performances are greatly improved by selecting the very small RDPS and very large dispersion coefficient of DCF.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.115-128
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• 2017

The purpose of this study is to examine the influence of the distributed leadership upon kindergarten teachers' commitment of teachers. As a result of the analysis, first, the teachers' recognition on the distributed leadership at a kindergarten was confirmed to have a significant difference depending on the teaching career and the academic background. And the commitment of teachers perceived by the kindergarten teachers was identified to have a statistically significant difference according to the teaching career, academic background, and scale. Second, the kindergarten situation and the teacher leadership among sub-factors of the distributed leadership were indicated to have a positive effect on the commitment of teachers. Especially, the teacher leadership was confirmed to have a positive impact on the whole of professional consciousness, educational love, and passion, which are sub-factors in the commitment of teachers. What the distributed leadership has a positive influence upon the commitment of teachers at a kindergarten can be known to be ultimately the time when a teacher oneself fully recognizes responsibility, influence, and authority with thinking that a teacher oneself is a leader, rather than a director's leadership. Accordingly, a director's many responsibilities and authorities need to be properly entrusted so that the kindergarten teachers can display much more leadership.

• Economic Analysis
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• v.25 no.1
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• pp.1-33
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• 2019

This paper examines the economic factors that are related to the dynamics of the variance risk premium, and specially, which economic factors are related to the forecasting power of the variance premium regarding future index returns. Eleven general economic variables, eight interest rate variables, and eleven sentiment-associated variables are used to figure out the relevant economic variables that affect the variance risk premium. According to our empirical results, the won-dollar exchange rates, foreign reserves, the historical/implied volatility, and interest rate variables all have significant coefficients. The highest adjusted R-squared is more than 65 percent, indicating their significant explanatory power of the variance risk premium. Next, to verify the economic variables associated with the predictability of the variance risk premium, we conduct forecasting regressions to predict future stock returns and volatilities for one to six months. Our empirical analysis shows that only the won-dollar exchange rate, among the many variables associated with the dynamics of the variance risk premium, has a significant forecasting ability regarding future index returns. These results are consistent with results found in previous studies, including Londono (2012) and Bollerslev et al. (2014), which show that the variance risk premium is related to global risk factors.