• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1163-1166
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• 2007

핸드오버가 발생하는 이동망 환경에서 주요 이슈 중 하나는 핸드오버 후 MN(Mobile Node)의 트래픽이 전송될 새로운 경로 상에 자원 재예약을 위한 지연 시간을 최소화하는 것이다. 이를 위해, 데이터 전달 경로가 변경된 경로에서만 자원예약 시그널링이 이루어지도록 CRN(Crossover Node)을 발견하는 것이 중요하다. 이동망 환경에서 자원 재예약을 위한 CRN은 SID(Session ID)를 이용하여 발견될 수 있다. 그러나 HMIPv6 네트워크에서 MAP(Mobility Anchor Point)과 HA(Home Agent)간 군집(Aggregate) 자원 예약이 이루어진 경우에서는 SID를 이용하여 CRN을 발견할 수 없다. 왜냐하면, MN의 핸드오버 후, 종단간 SID는 동일할지라도 이전 MAP과 HA간 설립된 세션의 군집 SID가 새로운 MAP과 HA간 설립된 세션의 군집 SID와 다르기 때문이다. 이에, 본 논문에서는 HMIPv6 네트워크에서의 CRN 발견방안을 제안한다. 제안하는 방안에서는 시그널링 메시지에 이전 군집 세션 정보를 포함하여 전달함으로서 시그널링 메시지가 목적지까지 도달하기 전에 CRN이 발견될 수 있도록 하였다. 제안하는 방안은 군집 자원예약이 갖는 시그널링 및 플로우별 상태 정보 감소 효과를 그대로 유지하면서, MN의 핸드오버 후, 자원 재예약을 위한 지연 시간을 단축시킴으로서 통신 성능을 향상 시킬 수 있을 것으로 기대된다.

• The Journal of the Korea Contents Association
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• v.11 no.3
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• pp.100-107
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• 2011

One of the important fields for heuristic algorithm is how to balance between Intensification and Diversification. In this paper, we deal with the performance improvement techniques through balance the intensification and diversification in Ant Colony System(ACS) which is one of Ant Colony Optimization(ACO). In this paper, we propose the hybrid searching method between intensification strategy and diversification strategy. First, the length of the global optimal path does not improved within the limited iterations, we evaluates this state that fall into the local optimum and selects the next node using changed parameters in the state transition rule. And then we consider the overlapping edge of the global best path of the previous and the current, and, to enhance the pheromone for the overlapping edges increases the probability that the optimal path is configured. Finally, the performance of Best and Average-Best of proposed algorithm outperforms ACS-3-opt, ACS-Subpath, ACS-Iter and ACS-Global-Ovelap algorithms.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.667-672
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• 2011

This paper presents to study the sensor fusion of positioning sensors using UKF(unscented Kalman filter) for positioning accuracy improvement of AGV(automatic guided vehicle). The major guidance systems for AGV are wired guidance and magnetic guidance system. Because they have high accuracy and fast response time, they are used in most of the FMS(flexible manufacturing system). However, they had weaknesses that are high maintenance cost and difficult of existing path modification. they are being changed to the laser navigation in recent years because of those problems. The laser navigation is global positioning sensor using reflecters on the wall, and it have high accuracy and easy to modify the path. However, its response time is slow and it is influenced easily by disturbance. In this paper, we propose the sensor fusion method of the laser navigation and local sensors using UKF. The proposed method is improvement method of accuracy through error analysis of sensors. For experiments, we used the axle-driven forklift AGV and compared the positioning results of the proposed method with positioning results of the laser navigation. In experimental result, we verified that the proposed method can improve positioning accuracy about 16%.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.489-496
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• 2002

This study proposes a new polling algorithm allowing dynamic change in polling period based on line utilization prediction. Polling is the most important function in network monitoring, but excessive polling data causes rather serious congestion conditions of network when network is In congestion. Therefore, existing multiple polling algorithms decided network congestion or load of agent with previously performed polling Round Trip Time or line utilization, chanced polling period, and controlled polling traffic. But, this algorithm is to change the polling period based on the previous polling and does not reflect network conditions in the current time to be polled. A algorithm proposed in this study is to predict whether polling traffic exceeds threshold of line utilization on polling path based on the past data and to change the polling period with the prediction. In this study, utilization of each line configuring network was predicted with AR model and violation of threshold was presented in probability. In addition, suitability was evaluated by applying the proposed dynamic polling algorithm based on line utilization prediction to the actual network, reasonable level of threshold for line utilization and the violation probability of threshold were decided by experiment. Performance of this algorithm was maximized with these processes.

• 한국해양학회지
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• v.30 no.1
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• pp.57-63
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• 1995

Two-layered fluid with sloping bottom and top(${\beta}$-effect) in rigid cylinder is put on the rotating table. To drive the lower-layer motion in "the Sverdrup type" flow external fluid is pumped into the lower-layer. By introducing inlet-outlet system in the upper-layer, an analogy to the Tsushima Tsugaru, Soya of the East Sea has been tested. The position of the inlet-outlet system and the difference between the strength of inlet or outlet flow are changed to see the effects of the wind stress on the upper-layer. The northern part of inflow toward the outlet may be interpreted roughly as the position of the polar front in the East Sea. Experimental observations have revealed that the inflow flows along the western boundary before it separates into the interior and flows straight toward the outlet position. However, the wind effect is imposed upon the upper-layer, the western boundary flow branches into two parts of which one flows along the boundary and the other flows into the interior under the influence of negative wind stress curl, while southward western boundary flow seems to block the flow and deflect it to the interior. The changes in the position of inlet-outlet system produce more significant changes in flow pattern in that cyclonic flow in the north controls the northern extent of the polar front by deflecting the northward interior motion toward the west(outlet). Interface displacement which depends strongly on the velocity difference between two layers seems to play crucial role in terms of the path of upper-layer flow, particularity, the inflow.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.4
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• pp.32-39
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• 2006

MANET is a dynamically reconfigurable wireless network with no fixed infrastructure (base station, or AP). In order to provide the data service in MANET, we need an efficient routing protocol to deliver the data to the wanted destination at a mobile node. A method of routing protocols called reactive routing protocol has recently got attention because of their low routing overhead. But a method of flooding broadcasts the packet to all of its neighbors. For this reason, each of the node has high routing overhead to route and keep path discovery. Accordingly in this paper, I propose an adaptive flooding scheme using N-hop look-ahead in MANET, md an optimal N value of doing flooding the packet to limited area. Because of being basically ignorant about topological changes, each of the node did not spontaneously cope with path alteration. But an efficient flooding scheme applying N-hop look-ahead is more resilient to topology changes than traditional algorithms. And also with this efficient flooding scheme, the simulation results demonstrate excellent reduction of routing overhead.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.70-79
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• 2011

The multi-path routing schemes that assigns labels to sensor nodes for the reliability of data transmission and the accuracy of an aggregation query over the sensor networks where data transfer is prone to defect have been proposed. However, the existing schemes have high costs for reassigning labels to nodes when the network topology is changed. In this paper, we propose a novel routing method that avoids duplicated data and reduces the update cost of a sensor node. In order to show the superiority of the proposed scheme, we compare it with the existing scheme through the various experiments. Our experimental results show that our proposed method reduces about 95% the amount of the transmitted data for restoration to node failure and about 220% the amount of the transmitted data for query processing over the existing method on average.

• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.57-66
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• 2017

In this paper, we suggest a novel physics-based real-time animation technique for vehicles, and introduce an easy and intuitive animation authoring tool which uses our proposed technique. After a user specifies a trajectory of a virtual car as input, our system produces a more accurate simulation faster than a previous research result. This is achieved by a trajectory splitting method based on directional features and a trajectory library. As a result, the user can create not only a car animation including lane changing and passing, but also a crash animation which is a rarely researched topic. Also, we propose a virtual car structure that approximates a real car's structure for real-time simulation, the resulting animation shows high plausibility such as a small vibration which occurs when the virtual car breaks and a deformation of when a car accident happens.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.783-790
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• 2013

Circular path generation for ball bar measurement using the simultaneous movement of two axes with at least one rotary axis requires the execution of CAM software. However, a change in the machine type or measurement condition requires a new execution of the CAM software, which is cumbersome. This paper presents a circular path generation technique that does not require CAM software and is applicable to different types of driving axes with an arbitrary structural configuration of machine tools and any ball bar setup condition. Mathematical equations are derived for three cases using the proposed technique. In addition, to inspect the measurement feasibility for avoiding physical interference among the ball bar parts, a tilting angle calculation is proposed. The validity of the proposed technique was verified by performing a ball bar experiment with A and C as the simultaneous axes of a five-axis machine tool.

• Product Safety
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• s.201
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• pp.66-69
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• 2010

(주)담솔은(이하 담솔)2006년 (주)삼율이라는 상호로 창립되어 지금까지 '캐어맨'을 브랜드로 하여 RFID, 스마트, 홈네트워크 시스템 개발을 통해 고객의 생활의 편리를 더하고자 회사의 기술력을 개발, 발전시켜 왔으며 2009년 8월 에는 기업부설연구소 인증을 받았고, 2010년 1월에는 벤처기업인증을 받았다. 담솔은 창립 된지는 오래지 않으나 많은 노력을 기울여 개발능력이 우수한 중소기업으로 인정 받고 있다. 2010년 2월 새롭게 변화된 이미지를 나타내고자 (주)담솔로 상호변경을 하고 친환경 녹색성장을 지향하는 전문기업으로 탈바꿈하고 있다.