• Title/Summary/Keyword: 문제 공간

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Parallelization of Metaheuristic Algorithms to Solve the Large-scaled Optimization Problem (대규모 최적화 문제의 해결을 위한 메타휴리스틱 알고리즘의 병렬화)

  • 이용환;류광렬
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2002.05a
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    • pp.435-441
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    • 2002
  • 전력시스템 등, 산업 전반의 많은 분야에 최적화 문제가 산재해 있다. 또한 이러한 최적화 문제를 해결하기 위한 많은 연구가 있었다. 특정 응용에 국한되지 않고 모든 응용에 적용 가능한 메타휴리스틱 알고리즘은 그 중 많은 비중을 차지하고 있으며, 가장 대표적인 방법은 유전알고리즘과 타부 탐색이다. 그러나 최적화 문제에 속하는 많은 문제들이 탐색공간이 방대하고 많은 제약이 존재하는 대규모 최적화 문제로서 기존의 메타휴리스틱 기법들을 그대로 이용해서는 빠른 시간 내에 최적의 해를 찾아내기 힘들다 본 논문에서는 대규모 최적화 문제의 하나인 발전기 기동정지 계획 문제를 해결하기 위하여 유전알고리즘과 타부탐색을 적용하고 그 성능을 분석한다. 그리고 각 방법을 병렬화하여 수행함으로써 병렬화를 통하여 시간상의 이득과 함께 부가 효과로서 집중화와 다각화의 효과를 얻을 수 있음을 보여준다.

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Women's Spatial-Temporal Entrapment in Access to Urban Opportunities by Child Age (자녀 연령별 여성의 도시기회 접근성의 시.공간적 구속성에 관한 연구)

  • Kim, Hyun-Mi
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.358-374
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    • 2008
  • This study examines whether and how ages of child affect accessibility experiences of women and men differently. Space-time accessibility measures based on Time-geographic framework with activity-travel diary datasets in Portland Metro, US were calculated using GIS-based geocomputation, and spatial-temporal patterns of accessibility of dual-earner couples by ages of their youngest child were compared. The results are as follows. (1) Although more women than men work part-time, which would render women more spatial-temporal autonomy, accessibility levels of women are not higher than men's. It implies that there exists another constraint placed on women which largely stems from gender inequality. (2) It is distinctively women with child under age 6 of which accessibility spaces are found to be restricted doser to home compared to men. Women with no child or with child aged over 6, however, show more or less similar spatial-temporal patterns of accessibility with men's which are quite unvarying regardless of parental status and their child age. Women's accessibility experiences characterized by spatial-temporal entrapment, thus, can be seen as problems associated with gender rather than sex. (3) Intensified spatial-temporal entrapment of women with young child are associated with the significant spatial pegs shaping their accessibility spaces, which are located much closer to home compared to men's: workplaces and child's daycare centers.

Spatial Computation on Spark Using GPGPU (GPGPU를 활용한 스파크 기반 공간 연산)

  • Son, Chanseung;Kim, Daehee;Park, Neungsoo
    • KIPS Transactions on Computer and Communication Systems
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    • v.5 no.8
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    • pp.181-188
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    • 2016
  • Recently, as the amount of spatial information increases, an interest in the study of spatial information processing has been increased. Spatial database systems extended from the traditional relational database systems are difficult to handle large data sets because of the scalability. SpatialHadoop extended from Hadoop system has a low performance, because spatial computations in SpationHadoop require a lot of write operations of intermediate results to the disk, resulting in the performance degradation. In this paper, Spatial Computation Spark(SC-Spark) is proposed, which is an in-memory based distributed processing framework. SC-Spark is extended from Spark in order to efficiently perform the spatial operation for large-scale data. In addition, SC-Spark based on the GPGPU is developed to improve the performance of the SC-Spark. SC-Spark uses the advantage of the Spark holding intermediate results in the memory. And GPGPU-based SC-Spark can perform spatial operations in parallel using a plurality of processing elements of an GPU. To verify the proposed work, experiments on a single AMD system were performed using SC-Spark and GPGPU-based SC-Spark for Point-in-Polygon and spatial join operation. The experimental results showed that the performance of SC-Spark and GPGPU-based SC-Spark were up-to 8 times faster than SpatialHadoop.

The Study on the Relationship between Chinese Food Culture and Kitchen Storage Space (현대 중국 식문화와 주방수납공간의 관계성에 대한 연구)

  • Xu, Yue;Choi, Kyung Ran
    • Korea Science and Art Forum
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    • v.19
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    • pp.405-415
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    • 2015
  • Recently the development of China has attracted all over the world, many scholars of different areas are interested in Chinese Culture and Chinese Market. After sixties of last century development of the economic of the South Korea closer to modernization, but there are many problems, one of them is the urban living style boasts of the features of concentration. Because of this phenomenon the lack of housing space become more serious. It also come to be a social problems. Therefore narrow residential area become inevitability. At the same time, effective utilization of housing space become a demand. Especially for those families with limited living space, it's meaningful for them. Between the China and the South Korea. Chinese have the same situation too, the different is kitchen space of chinese is closed. It means they have to cook in limited space. With increased supplies and more small appliances, an inevitable requirement is opening out the kitchen space, but unreasonable furnishings and living space reduces the efficiency of the kitchen, which has led to the discontent of users. From this, base on the investigation and analysis of diet&living space of most chinese apartment, and through differences kinds and places of storage items. With them I would combine the food culture and feature of storage space of China to solve problems of the efficiency of the kitchen.

Schema Integration Methodology and Toolkit for Heterogeneous and Distributed Geographic Databases

  • Park, Jin-Soo
    • Journal of Korea Society of Industrial Information Systems
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    • v.6 no.3
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    • pp.51-64
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    • 2001
  • Schema integration is one of the most difficult issues in the heterogeneous and distributed geographic database systems (GDSs). As the use of spatial information in various application areas becomes increasingly popular, the integration of geographic information has become a crucial task for decision makers. Most existing schema integration techniques described in the database literature, however, do not address the problems of managing heterogeneities among complex objects that contain visual data and/or spatial and temporal information. The difficulties arise not only from the semantic conflicts, but also from the different representations of spatial models. Consequently, it is much more complex to achieve interoperability in the area of geographic databases. This research attempts to provide a solution to such problems. The research reported in this paper describes a schema integration methodology and a prototype toolkit developed to assist in schema integration activities for GDSs.

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Reinforcement Learning based Dynamic Positioning of Robot Soccer Agents (강화학습에 기초한 로봇 축구 에이전트의 동적 위치 결정)

  • 권기덕;김인철
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10b
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    • pp.55-57
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    • 2001
  • 강화학습은 한 에이전트가 자신이 놓여진 환경으로부터의 보상을 최대화할 수 있는 최적의 행동 전략을 학습하는 것이다. 따라서 강화학습은 입력(상태)과 출력(행동)의 쌍으로 명확한 훈련 예들이 제공되는 교사 학습과는 다르다. 특히 Q-학습과 같은 비 모델 기반(model-free)의 강화학습은 사전에 환경에 대한 별다른 모델을 설정하거나 학습할 필요가 없으며 다양한 상태와 행동들을 충분히 자주 경험할 수만 있으면 최적의 행동전략에 도달할 수 있어 다양한 응용분야에 적용되고 있다. 하지만 실제 응용분야에서 Q-학습과 같은 강화학습이 겪는 최대의 문제는 큰 상태 공간을 갖는 문제의 경우에는 적절한 시간 내에 각 상태와 행동들에 대한 최적의 Q값에 수렴할 수 없어 효과를 거두기 어렵다는 점이다. 이런 문제점을 고려하여 본 논문에서는 로봇 축구 시뮬레이션 환경에서 각 선수 에이전트의 동적 위치 결정을 위해 효과적인 새로운 Q-학습 방법을 제안한다. 이 방법은 원래 문제의 상태공간을 몇 개의 작은 모듈들로 나누고 이들의 개별적인 Q-학습 결과를 단순히 결합하는 종래의 모듈화 Q-학습(Modular Q-Learning)을 개선하여, 보상에 끼친 각 모듈의 기여도에 따라 모듈들의 학습결과를 적응적으로 결합하는 방법이다. 이와 같은 적응적 중재에 기초한 모듈화 Q-학습법(Adaptive Mediation based Modular Q-Learning, AMMQL)은 종래의 모듈화 Q-학습법의 장점과 마찬가지로 큰 상태공간의 문제를 해결할 수 있을 뿐 아니라 보다 동적인 환경변화에 유연하게 적응하여 새로운 행동 전략을 학습할 수 있다는 장점을 추가로 가질 수 있다. 이러한 특성을 지닌 AMMQL 학습법은 로봇축구와 같이 끊임없이 실시간적으로 변화가 일어나는 다중 에이전트 환경에서 특히 높은 효과를 볼 수 있다. 본 논문에서는 AMMQL 학습방법의 개념을 소개하고, 로봇축구 에이전트의 동적 위치 결정을 위한 학습에 어떻게 이 학습방법을 적용할 수 있는지 세부 설계를 제시한다.

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Optimal Mixed Storage Methods Considering Rehandles of Inventories (재취급을 고려한 최적 혼적결정법)

  • Yang, Jee Hyun;Kim, Kap Hwan;Won, Seung Hwan
    • Journal of Intelligence and Information Systems
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    • v.12 no.3
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    • pp.33-46
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    • 2006
  • In order to decrease the number of handles, speed up retrieval operations, and manage products efficiently, the investment of facilities such as the installation of the storage equipment and the enlargement of the storage area may be attempted. However, the same objectives can be accomplished by utilizing the existing storage area efficiently. In many types of storage facilities, because of the limitation of storage areas, products are usually piled up, which may cause rehandles of inventories. Rehandles influence significantly the handling efficiency of warehouses. This study develops methods for minimizing rehandles of inventories to improve the operational efficiency of warehouses. A mixed storage problem is addressed for minimizing the expected number of rehandles. Optimization models are proposed and the genetic algorithm is applied to solve the problem.

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