• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.285-294
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• 2006

The requirements of Computer Supported Cooperative Work supporting efficient cooperative or collaborative works between multi-users have been increasing in distributed environments. The various technical sections such as group communication technology and distributed processing technology should be provided in Cooperative Work. The replicated development of Cooperative Work applications of a number of common requirements increases development costs enormously and duplicated investment parts. Therefore, systematical development environments are required to develop these common requirements and applications efficiently in Cooperative Work applications development. In this study, we propose the hierarchical role-based coordination model that improves the coordination model of legacy mobile agent to be appropriate in Cooperative Work applications, and design the development environment for Cooperative Work applications based on mobile agent. The proposed hierarchical role-based coordination model provides multi-layered group concepts of mobile agent, and enables implementation of efficient coordination policy per group. Additionally, it supports efficient Cooperative Work application development by role assignment per group unit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1075-1082
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• 2004

Wireless LAN is a rather mature communication technology connecting mobile terminals. IEEE 802.11 is a representative protocol among Wireless LAN technologies. The basic medium access control (MAC) mechanism of IEEE 802.11 is called distnbuted coordination function (DCF). DCF shows poor throughput and high drop rate as the number of stations and offered traffic load increase. In this paper we propose an effective mechanism using dynamic mimmum contention window(CWmin) in wireless LAN~ and show that performance improves via simulations. Proposed dynamic CWmin scheme exhibits superior performance as the number of stations and offered load grow. As, our proposed scheme is expected to be more effective in highly densed wireless LAN environment.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.11
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• pp.36-45
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• 1992

A numerical trajectory planning method for path-constrained trajectory planning is proposed which ensures collision-free and time-optimal motions for two robotic manipulators with limited actuator torques and velocities. For each robot, physical constraints of the robots such as limited torques or limited rotational velocities of the actuators are converted to the constraints on velocity and acceleration along the path, which is described by a scalar variable denoting the traveled distance from starting point. Collision region is determined on the coordination space according to the kinematic structures and the geometry of the paths of the robots. An Extended Coordination Space is then constructed` an element of the space determines the postures and the velocities of the robots, and all the constraints described before are transformed to some constraints on the behaviour of the coordination-velocity curves in the space. A dynamic programming technique is them provided with on the discretized Extended Coordination Space to derive a collision-free and time-optimal trajectory pair. Numerical example is included.

• Industrial Engineering and Management Systems
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• v.8 no.4
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• pp.213-220
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• 2009

A revenue sharing contract is one of the mechanisms that coordinate decision makers in a decentralized supply chain toward the consensual goal. The transfer prices between different echelons in the supply chain influence the total supply chain profits. The study aims to explore various transfer pricing heuristics on the supply chain coordination in terms of the supply chain profits and their interactions with the revenue sharing rate. A model is proposed for formulating the collaborative production and distribution planning in a decentralized supply chain with the revenue sharing mechanism. Experiment results indicate that the transfer price and the revenue sharing rate affect significantly the coordination. Among the studied pricing heuristics, the variable-cost pricing method led to the best SC profits. Raising the revenue sharing rate reduced the SC profits no matter what heuristics were employed. Furthermore, the experiments provide us clues for finding the optimal transfer price for the supply chain.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.23-37
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• 2001

This paper is concerned with the critical issue of allocating limited corporate resources among multiple products and between production and marketing functions of a functionally decentralized firm where the two geographically remote functions independently make decisions pertaining to their own decision-making domain. We attempt to demonstrate how IT can contribute to enhancing the quality of coordinating production and marketing functions from the perspective of resource allocation. To this end, we propose a prototype named ITBCS (IT-Based Coordination System) that works under LAN supported computing environments. We develop a comprehensive coordination scheme that can handle various cost functions for the resource constrained, multiple product case that huts been tittle discussed in literature. A preliminary version of ITBCS has been implemented for a hypothetical situation where LAN electronically wires distributed marketing and production computing nodes. Managerial implications are also discussed.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.629-631
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• 2005

The DASPRO (Protection Coordination Program for DAS) is one of the application programs for Distribution Automation System (DAS) of the KEPCO. Application programs developed by KEPCO provide optimal operation in distribution network. The DASPRO includes diverse functions to operate network as construction of database using existing information. creation of diagram for protection coordination. calculation of fault current. evaluation network. power quality monitoring, etc. The DASPRO can examine validity of setting values for protective devices by comparing to T-C curves. Unless the protection coordination is correct, the most suitable setting value for protection devices are displayed on the screen. In this paper, I will introduce the contents of the DASPRO.

• Proceedings of the CALSEC Conference
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• 2005.03a
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• pp.261-266
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• 2005

Web services provide an effective means to carry out coordinated transactions between multiple, independent business parties. While there are several specific protocols currently being discussed to address the coordination of web services-enabled business transactions, we consider the tentative hold protocol (THP) that allows the placement of tentative holds on business resources prior to actual transactions in order to provide increased flexibility in coordination. In this paper, we present a formal coordination framework for applying THP in conjunction with 2PC to the problem in which service providers independently manage resources and clients seek to acquire the resources from multiple providers as a single atomic transaction. The proposed framework facilitates the performance optimization of THP through effective parameterization with the notion of overhold size and hold duration. The simulation results show that the proposed adaptive approach yields a significant improvement over other non-adaptive policies.

• Journal of Communications and Networks
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• v.13 no.4
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• pp.339-344
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• 2011

Base station coordination has received much attention as a means to reduce the inter-cell interference in cellular networks. However, this interference reducing ability comes at the expense of increased feedback, backhaul load and computational complexity. The degree of coordination is therefore limited in practice. In this paper, we explore the trade-off between capacity and feedback load in a cellular network with coordination clusters. Our main interest lies in a scenario with multiple fading users in each cell. The results indicate that a large fraction of the total gain can be achieved by a significant reduction in feedback. We also find an approximate expression for the distribution of the instantaneous signal to interference-plus-noise ratio (SINR) and propose a new effective scheduling algorithm.

• STI Policy Review
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• v.5 no.2
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• pp.96-121
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• 2014

This study identifies and evaluates inter-ministerial coordination for developing digital content technology in Korea and Japan. It is conducted through a comparative analysis between Korean and Japanese governmental organizations and their decision making process. Media content had been regulated or promoted by ministries involving culture in both countries. The digitalization of traditional media, however, blurred boundaries between the cultural, technological, and industrial spheres, so ministries involving science and technology, economy and trade, or foreign affairs started to promote digital content technology in the late 1990s. This has been the cause of conflicts among ministries and sometimes led to policy duplication, which in turn weakens policy effectiveness. The competition and coordination of ministries and agencies can be seen through establishing or amending related laws, organizations, and programs. Structural holes are founded in the networks drawn among governmental agencies in charge of digital content, particularly in the field of intellectual property in Korea and online distribution technology in Japan.

• PNF and Movement
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• v.15 no.1
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• pp.13-25
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• 2017

Purpose: This study investigated the coordination and contribution of body segments during functioning. Methods: The relevant literature related to body segments and function were reviewed. Results: Efficient control of function is considered with regard to a participant's ability to perform a sequence of movements in body segments, which progresses from the head to the arm, trunk, pelvis, and leg segments. Each segment performs a specific role, which environment explorer using visual information for the head, reaching and grasping for the arms, a stabilizer for the trunk, and the distribution of COM in the pelvis and leg. Conclusion: During any of the movements, the momentum generated by the proximal segments is transferred to the adjacent distal segments in an appropriate sequence. In assessing function for clinical intervention strategies, the segment coordination, segment sequence, transfer of the center of body mass, asymmetrical ratio, muscle activity, and compensatory strategies should be considered.