데이터 분배 및 태스크 진행 스케쥴링을 통한 맵/리듀스 모델의 성능 향상

황인성(In-Sung Hwang),정경용(Kyung-Yong Chung),임기욱(Kee-Wook Rim),이정현(Jung-Hyun Lee) 한국콘텐츠학회 2010 한국콘텐츠학회논문지 Vol.10 No.10

Map/Reduce 는 최근에 많은 주목을 받고 있는 클라우드 컴퓨팅을 구현하는 프로그래밍 모델이다. 이 모델은 여러 대의 컴퓨터를 이용해서 규모가 큰 데이터를 처리하는 어플리케이션에서 사용된다. 따라서 구성된 컴퓨터들을 효율적으로 사용하기 위해서 데이터를 적당한 크기로 나눈 다음 각각의 컴퓨터에 효율적으로 분배시키는 과정을 결정하는 것이 중요하다. 또한 모델을 구성하고 있는 Map 단계와 Reduce 단계를 실행하는 계획도 성능에 많은 영향을 줄 수 있다. 본 논문에서는 대용량의 데이터를 분리해서 Map 태스크를 실행하는 클라우드 컴퓨팅 노드의 성능과 네트워크의 상태를 고려한 후 각각의 컴퓨팅 노드에게 효율적으로 분배하는 방법을 제안한다. 그리고 Map 단계와 Reduce 단계에서 진행하는 방식을 튜닝하여 Reduce 작업의 처리속도를 향상시켰다. 제안된 방법은 대표적인 두 개의 Map/Reduce 어플리케이션을 이용하여 실험하고 조건에 따라 성능에 어떠한 결과를 미치는지 평가했다. Map/Reduce is the programing model which can implement the Cloud Computing recently has been noticed. The model operates an application program processing amount of data using a lot of computers. It is important to plan the mechanism of separating the data in proper size and distributing that to a cluster consisted of computing node in efficient for using the computing nodes very well. Besides that, planning a process of Map phases and Reduce phases also influences the performance of Map/Reduce. This paper suggests the effectively distributing scheme that separates a huge data and operates Map task in the considering the performance of computing node and network status. And we make the Reduce task can be processed quickly through the tuning the mechanism of Map and Reduce task operation. Using the two Map/Reduce sample application, we experimented the suggestion and we evaluate suggestion considered it in how impact the Map/Reduce performance.

축소시스템 기반 비행체 날개 최적화

김현기,최인호 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.11

본 연구에서는 축소모델을 기반으로 비행체 날개를 최적화하는 기법을 제안한다. 잘 구축된 축소모델은 고유치 문제나 동적 해석 시 정확한 해석결과를 제공하며, 최적화 과정에서 필요한 민감도 계산에서도 정확한 결과를 제공할 수 있다. 이러한 축소모델은 모드기반으로 구축되는 축소차수모델(Reduce Order Model)과 자유도기반으로 구축되는 축소시스템(Reduced System)으로 구분되는데, 본 연구에서 사용하는 자유도 기반 축소시스템은 구조물의 거동에 지배적인 자유도를 적절히 선정하는 것이 중요하므로, 이를 위하여 기존 연구에서 신뢰성이 검증된 2단계 축소방법을 사용하였고, IRS(Improved Reduced System)에 의해 최종시스템을 구축하였다. 수치예제에서 최적화 과정에서 계산되는 등가응력, 고유치 및 설계민감도는 모두 축소시스템 기반으로 구해지며, 축소시스템을 통해 구속조건을 잘 만족하면서 목적함수에 대한 최적 결과를 얻을 수 있음을 보인다. The present study proposes the optimization of wing structure base on reduced model which assures the solution accuracy and computational efficiency. Well-constructed reduced model assures the accurate result in the eigenvalue problem, dynamic analysis or sensitivity of design optimization. Reduced system is classified into the reduce-order model based on structural modes and the reduced system based on degrees of freedom. Because this study uses the reduced system based on degrees of freedom, it is important to select the dominant degrees of freedom properly. For this work, robust selection method, two-level selection scheme, is employed and IRS(Improved Reduced System) is applied to construct the final reduced system. In the optimization process based on the reduced system, all of the equivalent stress, eigenvalue and design sensitivities are calculated from the reduced system. Through a numerical example, it is shown that the present optimization methodology based on the reduction method can provide an optimal results for objective function satisfying constraint condition.

축소시스템 기반 비행체 날개 최적화 연구

김현기(Kim, Hyun-Gi),최인호(Choi, In-Ho) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.10

본 연구에서는 축소모델을 기반으로 비행체 날개를 최적화하는 기법을 제안한다. 잘 구축된 축소모델은 고 유치 문제나 동적 해석 시 정확한 해석결과를 제공하며, 최적화 과정에서 필요한 민감도 계산에서도 정확한 결과를 제공할 수 있다. 이러한 축소모델은 모드기반으로 구축되는 축소차수모델(Reduce Order Model)과 자유도기반으로 구 축되는 축소시스템(Reduced System)으로 구분되는데, 본 연구에서 사용하는 자유도 기반 축소시스템은 구조물의 거동 에 지배적인 자유도를 적절히 선정하는 것이 중요하므로, 이를 위하여 기존 연구에서 신뢰성이 검증된 2단계 축소방 법을 사용하였고, IRS(Improved Reduced System)에 의해 최종시스템을 구축하였다. 수치예제에서 최적화 과정에서 계 산되는 등가응력, 고유치 및 설계민감도는 모두 축소시스템 기반으로 구해지며, 축소시스템을 통해 구속조건을 잘 만 족하면서 목적함수에 대한 최적 결과를 얻을 수 있음을 보인다. The present study proposes the optimization of wing structure base on reduced model which assures the solution accuracy and computational efficiency. Well-constructed reduced model assures the accurate result in the eigenvalue problem, dynamic analysis or sensitivity of design optimization. Reduced system is classified into the reduce-order model based on structural modes and the reduced system based on degrees of freedom. Because this study uses the reduced system based on degrees of freedom, it is important to select the dominant degrees of freedom properly. For this work, robust selection method, two-level selection scheme, is employed and IRS(Improved Reduced System) is applied to construct the final reduced system. In the optimization process based on the reduced system, all of the equivalent stress, eigenvalue and design sensitivities are calculated from the reduced system. Through a numerical example, it is shown that the present optimization methodology based on the reduction method can provide an optimal results for objective function satisfying constraint condition.

Map Reduce-based P2P DBaaS Hub system

Jung, Yean-Woo,Lee, Jong-Yong,Jung, Kye-Dong The Institute of Internet 2016 International journal of advanced smart convergenc Vol.5 No.1

The database integration is being emphasized to one way of the companies collaboration. To database integration, companies are use like one database what their own, it can be provided more efficient service to customer. However, there exist some difficulty to database integration. that is the database security and database heterogeneity problems. In this paper, we proposed the MapReduce based p2p DBaaS hub system to solve database heterogeneity problem. The proposed system provides an environment for companies in the P2P cloud to integrate a database of each other. The proposed system uses DBaaS Hub for a collection of data in the P2P cloud, and use MapReduce for integrating the collected data.

Map Reduce-based P2P DBaaS Hub system

Yean-Woo Jung,Jong-Yong Lee,Kye-Dong Jung 한국인터넷방송통신학회 2016 Journal of Advanced Smart Convergence Vol.5 No.1

The database integration is being emphasized to one way of the companies collaboration. To database integration, companies are use like one database what their own, it can be provided more efficient service to customer. However, there exist some difficulty to database integration. that is the database security and database heterogeneity problems. In this paper, we proposed the MapReduce based p2p DBaaS hub system to solve database heterogeneity problem. The proposed system provides an environment for companies in the P2P cloud to integrate a database of each other. The proposed system uses DBaaS Hub for a collection of data in the P2P cloud, and use MapReduce for integrating the collected data.

Map Reduce-based P2P DBaaS Hub system

Yean-Woo Jung,Jong-Yong Lee,Kye-Dong Jung 한국인터넷방송통신학회 2016 International Journal of Internet, Broadcasting an Vol.8 No.1

The database integration is being emphasized to one way of the companies collaboration. To database integration, companies are use like one database what their own, it can be provided more efficient service to customer. However, there exist some difficulty to database integration. that is the database security and database heterogeneity problems. In this paper, we proposed the MapReduce based p2p DBaaS hub system to solve database heterogeneity problem. The proposed system provides an environment for companies in the P2P cloud to integrate a database of each other. The proposed system uses DBaaS Hub for a collection of data in the P2P cloud, and use MapReduce for integrating the collected data.

Map Reduce-based P2P DBaaS Hub system

정연우,이종용,정계동 한국인터넷방송통신학회 2016 Journal of Advanced Smart Convergence Vol.5 No.1

The database integration is being emphasized to one way of the companies collaboration. To database integration, companies are use like one database what their own, it can be provided more efficient service to customer. However, there exist some difficulty to database integration. that is the database security and database heterogeneity problems. In this paper, we proposed the MapReduce based p2p DBaaS hub system to solve database heterogeneity problem. The proposed system provides an environment for companies in the P2P cloud to integrate a database of each other. The proposed system uses DBaaS Hub for a collection of data in the P2P cloud, and use MapReduce for integrating the collected data.

Effect of Shopping Bag Intervention to Community on Plastic Bag Waste Reduction in Bandung, Indonesia

( R. Audi ),( E. Sembiring ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

Waste is become one of many environmental problems in Bandung, Indonesia, especially plastic waste. Every year, there is increasing trend of the need of plastic about 200.000 tons annually in the country. Taking focus of plastic bag waste, it poses real environmental impacts because of its characteristic of low degradability so it may cause flooding by clogging the drainage, polluting the ocean, and producing toxic gases when burned. The first method of 3R concept, reduce, is used in this study by implementing the provision of shopping bags so that waste can be reduced. This study aims to determine the effect of intervention on plastic bag waste reduction. There are six sites with three levels of economic differences. Intervention is given to the three sites, while others are not. Waste sampling carried out by two phases, phase I performed before intervention and phase II performed after the intervention is completed. Intervention contains provision of shopping bags and information related to plastic bags. The result, Bandung produces waste up to 2.16 litres/person/day or 0.40 kg/person/day with the average composition of the waste plastic bag is 5.66% from total waste. In detail, ccomposition of plastic bag waste in the upper class community is 7.45%, the middle class is 5.35%, and the lower class is 4.18%. Test of significance, t-test of plastic bag waste from phase I and phase II, shows that the intervention has a significant effect on plastic bag waste reduction. On average, shopping bag intervention approach successfully reducing plastic bag waste up to 35% in the study area.

편심캠을 이용한 소형감속기의 변속특성에 관한 연구

염광욱(Kwang-Wook Youm),함성훈(Seong-Hun Ham) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.3

본 연구에서는 부피는 기존 1단 감속기와 동일한 수준을 유지하면서 2단의 감속비를 갖는 소형감속기에 대한 개발을 위하여 새로운 형태의 편심캠을 이용한 감속기의 연구를 진행하였다. 따라서 자동차에 적용되는 무단변속기의 개념을 이용하여 2단 감속기를 설계하였다. 캠은 감속풀리와 가속풀리에 각각 연결되어있는 V-벨트를 압착하여 미끄러짐을 최소화하기 위하여 텐셔너 역할을 할 수 있도록 180˚의 위상차를 두고 편심형태를 가지는 구조로 설계하였다. 또한 캠의 직경을 35mm로 하고, 외경의 폭을 18mm로 하여 v-벨트의 외측부분과 캠이 완벽하게 접촉할 수 있는 구조로 설계하였다. 감속을 위한 저속풀리는 입력축에 지름 50.8mm의 풀리를 설치하고, 출력축에 지름76.2mm의 풀리를 설치하였다. 가속을 위한 고속 풀리에는 입력축에 지름 76.2mm의 풀리를 설치하고, 출력축에 지름 50.8mm의 풀리를 설치하였다. 설계된 내용을 토대로 변속기의 동력전달효율실험과 발열특성에 대한 실험을 진행하여 타당성을 검증하였다. 또한 타당성 검증을 통하여 감속기의 적합성을 증명하였다. In this study, a new type of eccentric cam was used for the development of a small size reducer with a two-shift reduction ratio while maintaining the same volume as the existing one-shift speed reducer. Therefore, a two-shift speed reducer was designed using the concept of a continuously variable transmission applied to automobiles. The cam was designed to have an eccentric shape with a 180° phase difference to act as a tensioner to minimize slip by squeezing the V-belt connected to the deceleration pulley and the acceleration pulley, respectively. The cam was designed to have a diameter of 35mm and an outer diameter of 18mm so that the outer portion of the v-belt could contact the cam perfectly. A pulley with a diameter of 50.8mm was installed on the low speed pulley input shaft for deceleration and a pulley with a diameter of 76.2mm was provided on the output shaft. In the high-speed pulley for acceleration, a pulley with a diameter of 76.2mm is provided on the input shaft, and a pulley with a diameter of 50.8mm is provided on the output shaft. Based on the design details, the power transmission efficiency test and the heating characteristics of the transmission were tested to verify the feasibility. In addition, through validation, the suitability of the reducer was demonstrated.

최근 국제적 동향에서 바라 본 우리 民法上의 賣渡人의 瑕疵擔保責任에 관한 硏究

사동천(Sha, Dong-Cheon) 한국민사법학회 2003 民事法學 Vol.24 No.-

This thesis is to study about the Seller s Defects Liability on Movables in the light of international s trend. I have the opinion that the conclusion drawn out through comparative laws is acceptable in the light of the theory of the nonperformance of an obligation liability, it is a starting point to settle problems of our Civil Code. And, this thesis suggests legislative solutions. 1. Interpretation of Seller s Liability for Warranty against Defects in Korean Civil Law First. there is no provisions of the concept of defect in our Civil Code and Commercial Code. I think that it is preferable to understand the concept of the defect on movables as non-conformity of contract, which include discrepancy of explicit agreements, aliud-delivery, non-conformity of packaging, it consists of nonperformance of an obligation liability. Non-conformity of contract is decided first by the agreements of contract between parties. Except where the parties have agreed otherwise, goods must be fit for the ordinary purposes, any particular purposes, and expressed implied warranty. On the end, it is decided by making clear the purpose of contract. Second, I think that the repair of defect can be admitted, if we can regard articles 580, 581 of Civil Law as examples in remedies. On the other hand, I think that the buyer s right to require performance can extend to the repair of the goods, in Article 389 of Korean Civil Law, Because both liability systems are similar, in fact that there is not the requirement of a fault for remedy of the Buyer right. I think that the buyer may exercise the seller claims of repair and part of delay in both liability systems. Third, the condition of avoidance of contract should be interpreted in stricter manner than the condition of the other remedies. I think that the concept of the impossibility meeting contract goal in our civil law is superior to a fundamental nonperformance (fundamental breach of contract) in the light of 「 contract maintenance rule」. Fourth, I suggest that damages should be interpreted to mean the 「Performance Guarantee」, because avoidance or damages can exercise alternatively with a claim for delivery of substitute goods in Art 582(2) Civil Code, and stands on the premise that both rights have equivalent values, 2. legislative solutions(The Accommodation of International Theories) First. the repair of the defective goods should be viewed as a major right of the buyer. And it should not be restricted in case of defects which could not accomplish the purpose of contract, although when the repair costs excessively. Second, though it is common to limit a period of notification on the defect in trading between merchants to reasonable period from the time of recognition of the defect. It is not desirable to limit the period of notification on the defect of the hidden defect on goods to 6 months from the time of receiving. This period is unjustifiably short comparatively with international standard. Legislatively it is required either to extend the period to 1 year or 2 years or to replace the Article with a period for exercising the right. Third, comparatively it is more common to require buyer s recognition of defect and gross mistake for the ignorance of defect. Accordingly it will be legislatively desirable to require a recognition and a gross mistake of buyer as a requisite of elimination of liability, with the exceptions of when there are a recognition and a gross mistake of the seller and when the seller guarantees nature and characteristics of goods. Fourth, it needs that reduction of price is institutionalized as an ultimate remedy and the Bill of Amendment of Civil Law by Department of Justice provided right to reduce price in Article 580 section 1. But it did not provide about the basic time and method for the calculation of the amount reduced.