• Journal of Korean Institute of Industrial Engineers
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• v.29 no.3
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• pp.213-221
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• 2003

In this paper, we consider a multi-objective part-machine grouping problem, in which part types have several alternative part routings and each part routing has a machining sequence. This problem is characterized as optimally determining part type sets and its corresponding machine cells such that the sum of inter-cell part movements and the sum of machine workload imbalances are simultaneously minimized. Due to the complexity of the problem, a two-stage heuristic algorithm is proposed, and experiments are shown to verify the effectiveness of the algorithm.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.4
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• pp.253-258
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• 2003

We consider the problem of grouping orders into lots. The problem is modelled by a graph G=(V,E), where each node ${\nu}{\in}V$ denotes order specification and its weight ${\omega}(\nu)$ the orders on hand for the specification. We can construct a lot simply from orders of single specification. For a set of nodes (specifications) ${\theta}{\subseteq}V$, if the distance of any two nodes in $\theta$ is at most d, it is also possible to make a lot using orders on the nodes. The objective is to maximize the number of lots with size exactly $\lambda$. In this paper, we prove that our problem is NP-Complete when $d=2,{\lambda}=3$ and each weight is 0 or 1. Moreover, it is also shown to be NP-Complete when $d=1,{\lambda}=3$ and each weight is 1,2 or 3.

• IE interfaces
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• v.19 no.1
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• pp.1-8
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• 2006

The mobile communication network has to offer good quality of services (QoS), high capacity, and more coverage at a lower cost. However, with the increase of cellular user, the shortage of capacity due to unbalanced call distribution and lack of QoS are common. This paper deals with dynamic sectorization for efficient resource management to solve load unbalancing among microcells in CDMA (Code Division Multiple Access) microcellular system. Dynamic load balancing can be effected by grouping micro-cells properly and grouping can be developed through a routing mechanism. Therefore, we use ants and their routes to choose the optimum grouping of micro-cells into sectors using Multiple Ant Colony System (MACS)in this paper.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.59-64
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• 2002

This paper presents a method for line segment extraction for 3-d building reconstruction. Building roofs are described as a set of planar polygonal patches, each of which is extracted by watershed-based image segmentation, line segment matching and coplanar grouping. Coplanar grouping and polygonal patch formation are performed per region by selecting 3-d line segments that are matched using epipolar geometry and flight information. The algorithm has been applied to high resolution aerial images and the results show accurate 3-d building reconstruction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.567-570
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• 2010

In this paper, A Detection Algorithm of Dead Stone for the Go program based on the Grouping is proposed. The group of the same color as the stone is connected to the left, right, up and down side in the same group is defined to be grouping. A Detection Algorithm of Dead Stone based on these groups to remove stone and all the stones of the same color as the stones of the same group, regardless of the Case for TILT blocked, if satisfied that the detection of the group is treated as a dead stone.

• Journal of IKEEE
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• v.22 no.4
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• pp.1099-1103
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• 2018

Platooning of vehicles is an efficient traffic management model that improves traffic flow and fuel consumption. Especially, it is necessary to reduce computational load and networking overhead in automated connected vehicle systems. Because it is important to maintain the size of the platoon group appropriately for efficient platoon operation, this study proposed a dynamic grouping scheme for platooning in an automated vehicle system. The proposed scheme is analyzed by a mathematical model based on Markov chain. From the performance evaluation, it was confirmed that the proposed scheme appropriately controls the size of the platoon group.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1200-1201
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• 2010

인터넷 및 서비스 환경의 발전으로 인해 컴퓨터 통신의 환경이 변함에 따라 기존의 유니캐스트 전송방식에서 멀티캐스트 전송 방식을 이용한 그룹 통신이 증가하고 있다. 그러나 멀티캐스트 전송 방식의 취약점 및 키 관리의 어려움으로 인해 많은 문제점이 발생하면서 멀티캐스트 환경에서 안전하고 효율적인 키 관리 방법에 대한 연구의 필요성이 대두되고 있다. 따라서 본 연구에서는 멀티캐스트 환경에서 dynamic grouping을 이용한 키 관리 프로토콜을 제안하여 안전성과 효율성을 제공하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.31-34
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• 2009

유비쿼터스 환경에서 상황인지 능력을 가진 지능적 컴퓨팅 개체들 중 사람에게 의존적이지 않고 독립적으로 행동할 수 있는 개체는 유비쿼터스 로봇으로 볼 수 있다. 이러한 로봇은 최근 상호협력 함으로서 보다 최적화된 서비스를 제공하는 연구가 진행되고 있으며, 또한 다수의 로봇이 포함된 환경일 때는 특정한 작업을 수행하기 위하여 특정 로봇의 선별에 관한 연구가 진행 중이다. 본 논문에서는 유비쿼터스 환경에서 서로 다른 기능과 구조를 가지고 있는 지능형 로봇들이 협력하여 특수한 상황이나 임무를 그룹으로 대처할 수 있는 로봇 그룹핑을 설계하고 이를 구현한 결과에 대하여 기술한다. 다수의 로봇 중에서 특정 임무수행을 위한 로봇의 선별 알고리즘은 Entropy를 이용하여 결정 트리를 생성하였다. 또한 Grouping을 위한 Group Layer를 설계하여 구현하였다.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.121-130
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• 2011

This paper highlights the reconstruction of the rectilinear type of 3D rooftop model from satellite image data using centroid neural network. The main idea of the proposed 3D reconstruction method is based on the grouping of 3D line segments. 3D lines are extracted by 2D lines and DEM (Digital Elevation Map) data evaluated from a pair of stereo images. Our grouping process consists of two steps. We carry out the first grouping process to group fragmented or duplicated 3D lines into the principal 3D lines, which can be used to construct the rooftop model, and construct the groups of lines that are parallel each other in the second step. From the grouping result, 3D rooftop models are reconstructed by the final clustering process. High-resolution IKONOS images are utilized for the experiments. The experimental result's indicate that the reconstructed building models almost reflect the actual position and shape of buildings in a precise manner, and that the proposed approach can be efficiently applied to building reconstruction problem from high-resolution satellite images of an urban area.

• Journal of The Korean Association For Science Education
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• v.19 no.3
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• pp.400-408
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• 1999

This study investigated the effect of the grouping method in cooperative learning applied to chemistry concept learning. Two grouping methods used were the HML (High-Medium-Low) and the HL/MM (High-Low/Medium-Medium) ability grouping. Three classes (N = 136) at a high school in Seoul were randomly assigned to the control and the treatment groups. Before instruction. the test of attitude toward science instruction, the perception questionnaire of learning environment consisting of three subtests (participation, conflict, and competition), and the questionnaire of self-esteem were administered, and a mid-term examination score was obtained. These scores were used as covariates. After instruction, the three tests administered before instruction and the conceptions test were administered. Two-way ANCOVA results revealed that there was a significant interaction between the treatment and the level of previous achievement. The low-level students in the HL/MM cooperative group performed better than those in the other groups. The cooperative groups, regardless of the grouping methods, exhibited more positive perception than the control group at participation subtest of the perception questionnaire of learning environment.