• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.32-36
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• 1992

This paper develops the dynamic equivalents program combined with graphic user interface(GUI), to solve the stability of large power system. The p개posed method is coherency-based dynamic equivalents for transient stability studies. The program also provides with pull-down menu and Hangout help information for users. The developed dynamic equivalents program is suitable for the transient stability studies of a large power system with lots of data. The dynamic equivalents demonstrated over the New England system with 39 buses and 10 generators.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.362-367
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• 2011

The collision-free path of a manipulator should be regenerated in the real time to achieve collision safety when obstacles or humans come into the workspace of the manipulator. A probabilistic roadmap (PRM) method, one of the popular path planning schemes for a manipulator, can find a collision-free path by connecting the start and goal poses through the roadmap constructed by drawing random nodes in the free configuration space. The path planning method based on the configuration space shows robust performance for static environments which can be converted into the off-line processing. However, since this method spends considerable time on converting dynamic obstacles into the configuration space, it is not appropriate for real-time generation of a collision-free path. On the other hand, the method based on the workspace can provide fast response even for dynamic environments because it does not need the conversion into the configuration space. In this paper, we propose an efficient real-time path planning by combining the PRM and the potential field methods to cope with static and dynamic environments. The PRM can generate a collision-free path and the potential field method can determine the configuration of the manipulator. A series of experiments show that the proposed path planning method can provide robust performance for various obstacles.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.137-149
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• 2006

In this paper, we suggest a message-based communication protocol and a dynamic role assignment mechanism for efficient cooperation and teamwork of agents in computer game environments. This role assignment mechanism is a new one different from both existing static and dynamic mechanisms, in which all decisions related with role assignment are made at once in design phase or execution phase. According to our mechanism, all possible role sets are determined in design phase. Detail decisions regarding which agent takes what role, however, are made in execution phase. This mechanism for role assignment can minimize the negotiation effort in execution phase. Therefore, this mechanism is quite effective especially in real-time multiagent environments. Through experiments, we show the superiority of the new dynamic role assignment mechanism.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.379-387
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• 2019

The complexity of path planning for visiting multiple mission points is even larger than that of single pair path planning. Deciding a path for visiting n mission points requires conducting $n^2+n$ times of single pair path planning. We propose Multiple Mission $D^*$ Lite($MMD^*L$) which is an optimal path planning algorithm for visiting multiple mission points in dynamic environments. $MMD^*L$ reduces the complexity by reusing the computational data of preceding single pair path planning. Simulation results show that the complexity reduction is significant while its path optimality is not compromised.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1227-1233
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• 2011

An effective method of obstacle avoidance for omni-directional mobile robots is proposed to avoid moving obstacles in dynamic environments. Our method uses the concept of circle lists which represent the trajectories of robot and obstacles. This method predicts not only collision position but also collision time, and hence it enables the robot avoiding the most urgent collision first. In order to avoid obstacles, our method uses artificial repulsive force and contraction force. Simulation results show that the robot could avoid obstacles effectively.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.233-238
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• 2010

This paper describes a multi-mobile robot system with fuzzy rule based structure in collision avoidance. Collision avoidance is an important function to perform a given task collaboratively and cooperatively in multi-mobile robot environments. So the important but challenging problem is handled in this paper. Considered obstacles for collision avoidance between multi mobile robots are static, dynamic, or both of them at the same time. Using the fuzzy rule based structure, distance and angle from a robot to obstacles are described as fuzzy linguistic values and steering angle for the robot are updated from the collision environments. As a result, the multi-mobile robot can modify a global path from a robot itself to its own target. In addition, avoiding collision with static or dynamic obstacles for the robot system can be achieved. Simulation based experimental results are given to show usefulness of this method.

• Architectural research
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• v.14 no.1
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• pp.3-9
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• 2012

Owing to the advent of ubiquitous computing technologies, the concept of Intelligent Environments has emerged, as an alternative approach to overcome the limitation of the built environment. Intelligent Environments can be more responsive to user-and context-specific human activities by automatically and dynamically modifying their settings without explicit human intervention. However, the conventional approach to the development of Intelligent Environments has mainly focused on the technical issues without paying much attention to the dynamic interrelationship between the user and the built environment. Therefore, differing or conflicting needs of multiple simultaneous users remain unresolved. The objective of this study is to present types of environmental conflicts and their resolution through agent collaboration and negotiation. For the demonstration and validation of the conflict resolution process, a set of hypothetical test cases is simulated in a 3D test environment. The result of the case simulations shows that the proposed approach is computationally feasible and applicable to the development of Intelligent Environments, and, furthermore, it can overcome the drawback of the conventional approach.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.6
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• pp.724-733
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• 1999

An effective method of system modeling and dynamic scheduling for the back-end line of semiconductor manufacturing is proposed. The virtual factory, describing semiconductor manufacturing line, is designed in detail, and then a Petri net model simulator is developed for operation and control of the modular cells of the virtual factory. The petri net model is a colored timed Petri nets (CTPNs). The simulator will be utilized to analyze and evaluate various dynamic status and operatons of manufacturing environments. The dynamic schedulaer has a hierarchical structure with the higher for planning level and the lower for dynamic scheduling level. The genetic algorithm is applied to extract optimal conditions of the scheduling algorithm. The proposed dynamic scheduling is able to realize the semiconductor manufacturing environments for the diversity of products, the variety of orders by many customers, the flexibility of order change by changing market conditions, the complexity of manufacturing processes, and the uncertainty of manufacturing resources. The proposed method of dynamic scheduling is more effective and useful in dealing with such recent pressing requirements including on-time delivery, quick response, and flexibility.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.2
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• pp.154-160
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• 2006

Instantaneous reaction and intelligence are required for autonomous mobile robots to achieve multiple goals in the unpredictable and dynamic environments. Design of the appropriate control architecture and clear definitions of systems are needed to construct and control these robots. This research proposes the hybrid deliberative/reactive control architecture which consists of three layers and uses the method of software structure design. The highest layer, Deliberative Layer makes the overall run-time schedule for navigation and/or manipulation, and the middle layer, Task Execution Layer carries out various missions. The lowest layer, Reactive Layer enables a robot to react rapidly in the dynamic environment and controls the mechanical devices concurrently. This paper proposes independent system supervisors called Manager to reuse the modules so that the Manager supports common use of the system and multi-processing tasks. It is shown that the mobile robot based on the proposed control scheme can perform the basic navigation and cope with the dynamic obstacles reasonably well.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.476-481
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• 2012

Recently, QoS/QoE technology as a part of the HTTP-based adaptive streaming technology has attracted attention. In this paper, we find out HTTP-based adaptive and dynamic streaming technology. It is based on a dynamic adaptive streaming system over HTTP, which is designed and implemented. The system consist of conversion by the bit rate of MPEG2-TS files, division of segment, creation of MPD(Media Presentation Description) and bitrate's player through analysis of MPD File between servers and clients in network environments of dynamic and adaptive. This diverse network environments, continuous and smooth playback of video will be used in various multimedia fields.