• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.707-714
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• 2002

This paper presents a real-time Hausdorff matching algorithm for tracking of moving object acquired from an active camera. The proposed method uses the edge image of object as its model and uses Hausdorff distance as the cost function to identify hypothesis with the model. To enable real-time processing, a high speed approach to calculate Hausdorff distance and half cross matching method to improve performance of existing search methods are also presented. the experimental results demonstrate that the proposed method can accurately track moving object in real-time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2256-2271
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• 1997

In this paper, we analyze the multipath fading and the inter-satellite interference considering the satellite mobility in the LEO mobile satellite communication networks and evaluate the link perfodrmance for various wave propagation environments and reliabilities of communiation system. Multipath fading is estimated by analyzing the variation of fading margin for the satellite motion in rural, urban and suburban environments. The inter-satellite interferences are classified into 8 bypes with respect to interference path. The interferences evaluated in the paper are as follows:intra-LEO satellite interference, inter-LEO satellite interference, and GEO satellite to LEO satellite interference. As a conclusion, this apaper analyzes the change of elevation anagle and propagation distance with respect to time in the LEO satellite netwoek and prosents the variation of link margin continuously.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.25-28
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• 2008

본 논문에서는 GB-SAR의 간섭기법을 이용하여 물체의 변위 측정에 대한 정밀도를 조사하였으며, 또한 대기보정을 거친 후 정밀도의 변화에 대해서 확인하였다. GB-SAR 시스템에서 안테나는 중심주파수 5.3 GHz, 밴드 폭 600 MHz인 C밴드 안테나를 사용하였고, 신호의 증폭을 위해 마이크로파 앰프를, 다편파 측정 및 분석을 위하여 스위치를 장착하였다. 레일의 총 길이는 5 m, 이동간격은 5 cm, 최대 관측 거리는 약 200 m이다. 변위 측정에 사용된 이동산란체는 trihedral corner reflector로서, 시스템 전방 약 160 m에 위치하며 시스템 방향으로 1 mm에서 40 mm 전진시켰다. 이동산란체의 실제 변위와 GB-SAR 시스템의 위상변화로 관측된 변위의 상관계수는 편파에 따라 0.9995에서 0.9996으로 나타났다. 마이크로파의 전파과정에서 거리와 습도에 따른 지연 효과를 고려하기 위하여 대기보정식을 구하였으며, 이를 이동산란체의 위상에 적용한 결과 상관계수는 0.9997에서 0.9999의 값을 나타냈고 40 mm 이동시 오차가 1 mm 이내를 나타냄으로서 대기보정을 통한 결과가 더 높은 정밀도를 나타냄을 확인하였다.

• Korean Security Journal
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• no.15
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• pp.303-316
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• 2008

One of important protecting skill is securing the minimum safe distance from potential hazard to protect protectee in the emergency situation, that is basic thing for the detailed security in relation to the walking formation and the distance between protectee and crowed. This thesis is to provide the idea on the scientific countermeasure in the gun attack situation, by presenting logic on the reaction time and it's moving distance, on the safe distance between protectee and crowed. Handball goal keeper's reaction time of 0.33seconds is applied, because handball goal keeper's reaction style is very similar to security agent's reaction style. And 4m/sec of record is applied, that is average speed of 'go and return type run of 40m' to calculate it's moving distance. Several researches show that reaction time could be improved by continuing training, similarly security agents could improve their reaction time, providing better reaction skill. The important thing is that it make big difference in the protecting result, although the shortening of reaction time is too slight. Securing safe distance between protectee and crowed and the distance between protectee and security agent could provide effective reaction environment with 'natural protective wall effect' by security agent

• Journal of KIISE:Information Networking
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• v.32 no.5
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• pp.625-632
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• 2005

Recently, real time services have been demanding a lot and the number of mobile devices is increasing extremely. Many researchers are focusing on decreasing handoff or signaling cost, produced when mobile devices are moving around. With these efforts, HMIPv6(Hierarchical Mobile Internet Protocol Version 6) was proposed. Mobile nodes do not need to register their locations to Home Agents whenever crossing over subnets within a MAP domain. In HMIPv6, mobile nodes choose the farthest MAP without considering node mobility pattern. However, a large MAP domain is not always efficient for a slow moving node and required additional work to choose a MAP in HMIPv6. Hence, this paper proposes 'Performance Analysis of HMIPv6 applying adaptive MAP Domain Site'.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.352-354
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• 2022

Position measurement using a camera has been studied for a long time. This is being studied for distance recognition or object recognition in autonomous vehicles, and it is being studied in the field of indoor navigation, which is a limited space where GPS is difficult to apply. In general, in a method of measuring the distance using a camera, the distance is measured using a distance between the cameras using two stereo cameras and a value measured through a captured image or photo. In this paper, we propose a method of measuring the distance of an object using a single camera. The proposed method measures the distance by using the distance between cameras, such as a stereo camera, and the value measured by the photographed picture through the gap of the photographing time and the distance between photographing.

• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.137-142
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• 2023

In This paper, we propose a determine the correlation between bat swing speed and balance ability in elementary school baseball players. This study subjects were 40 subjects. Bat swing speed was measured using a zepp2baseball, and balance ability was measured using a biorescue. For the measurement of balance ability, eyes open surface·eyes open length·eyes open average speed·eyes close surface·eyes close length·eyes close average speed were measured. pearson's correlation analysis was used to analyze the correlation between bat swing speed and balance ability. There was a significant negative correlation between bat swing speed and eyes close surface (r=-0.366, p<0.05). There was a significant negative correlation between bat swing speed and eyes close length(r=-0.348, p<0.05). There was a significant negative correlation between bat swing speed and eyes close average speed(r=-0.455, p<0.01). Among them, eyes close average speed showed the highest correlation (p<0.01). These findings suggest that improvement of the balance ability has a positive effect on bat swing speed.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.255-258
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• 1998

이동로봇이 움직이는 물체를 추적하는 기능을 갖도록 하기 위해서는 움직이는 물체의 존재를 판단하고 위치 및 속도벡터를 측정해야 한다. 본 논문은 단시간에 이동 물체의 위치와 속도벡터 추정하여 실시간 추적이 가능하도록 하기 위해 초음파센서를 이용한 가상의 초음파영상 해석방법을 제안한다. 초음파 영상은 초음파센서의 매회 측정값을 누적하여 구성하며 거리축과 시간축을 갖는 2차원 영상으로 표현된다. 영상에서 측정된 물체가 만드는 선분의 기울기에 따라 이동하는 물체와 정지한 물체를 분리하고 속도를 측정한다. 제안된 방법은 시뮬레이션을 통해 타당성을 입증하였다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.294-295
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• 2002

우리나라는 위도상 중위도 편서풍대에 위치하고 있어 황하유역과 중국 및 몽고사막 등에서 발생한 토양먼지가 매년 3-5월경에 편서풍을 타고 1,500-2,000km 이상의 거리를 이동하는 황사와 같은 대기오염 물질의 장거리 이동현상이 매년 발생하고 있다. 장거리 이동되는 황사의 성상은 발원지에서의 토양성분 이외에도 이동과정 중에서 오염된 지역의 가스상 물질들이 추가되고 가스와 입자의 상호작용에 의해 황산염이나 질산염 등이 많이 생성된다. (중략)

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.23-29
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• 2004

In this paper, we propose a search method for time sequences which supports the normalized distance as a similarity measure. In many applications where the shape of the time sequence is a major consideration, the normalized distance is a more suitable similarity measure than the simple Lp distance. To support normalized distance queries, most of the previous work has the preprocessing step for vertical shifting which normalizes each sequence by its mean. The proposed method is motivated by the property of sequence for feature extraction. That is, the variation between two adjacent elements of a time sequence is invariant under vertical shifting. The extracted feature is indexed by the spatial access method such as R-tree. The proposed method can match time series of similar shape without vertical shifting and guarantees no false dismissals. The experiments are performed on real data(stock price movement) to verify the performance of the proposed method.