• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.42-47
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• 2012

Objective : The aim of this prospective study was to demonstrate the influence of some factors on the prognosis of microvascular decompression in 37 patients with trigeminal neuralgia. Methods : The results of microvascular decompression (MVD) in 37 patients with trigeminal neuralgia were evaluated at 6 months after surgery and were compared with clinical and operative findings. Results : The sex of the patient, the patient's age at surgery, the side of the pain, and the duration of symptoms before surgery did not play any significant roles in prognosis. Also, the visual analogue scale (VAS) of the patient, the duration of each pain attack, and the frequency of pain over 24 hours did not play any significant roles in prognosis. In addition, intraoperative detection of the type of conflicting vessel, the degree of severity of conflict, and the location of the conflict around the circumference of the root did not play any roles in prognosis. The only factors affecting the prognosis in MVD surgery were intraoperative detection of the site of the conflict along the root and neuroradiological compression signs on preoperative magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA). Conclusion : These findings demonstrated that if neurovascular compression is seen on preoperative MRI/MRA and/or compression is found intraoperative at the root entry zone, then the patient will most likely benefit from MVD surgery.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.265-273
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• 2008

Video Image Processing (VIP) for traffic surveillance has been used not only to gather traffic information, but also to detect traffic conflicts and incident conditions. This paper presents a system development of gathering traffic information and conflict detection based on automatic calculation of pixel length within the detection zone on a Video Detection System (VDS). This algorithm improves the accuracy of traffic information using the automatic detailed line segmentsin the detection zone. This system also can be applied for all types of intersections. The experiments have been conducted with CCTV images, installed at a Bundang intersection, and verified through comparison with a commercial VDS product.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.977-985
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• 2011

Airborne separation assurance is a key requirement for Free Flight Airspace operations, This paper study the feasibility of airborne separation assurance for free flight Airspaces operations by evaluating the efficiency measurement models. Three qualitatively different methods are utilized; one based Ground and Air conflict probability model, other based Dynamic Density model. the other based Direct operating cost model. The evaluation is Direct Operating Cost model and Two metrics are utilized for the efficiency measurements; airborne separation assurance performed quite well in the Free Flight evaluation; (1) 2 scenario of the conflict situations are resolved; (2) The MD-80 flight peformed separation assurance and efficiency, Not only appling for geometric method algorithm is more efficiently than potential method, but also the most efficiently geometric combined method.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1054-1059
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• 2005

본 논문은 철도청 사령실 통합 신호설비 구축사업에 적용할 열차 경합의 효과적인 해소 기법을 제시하고자 한다. 열차경합의 검지 및 해소 시스템 (Railway Conflict Detection and Resolution System)은 열차 운행관리 시스템(Railway Traffic Management System, RTMS)의 의사결정 지원 모듈이다. 이 모듈은 열차운행의 정시성을 유지하기 위하여 매우 중요한 기능을 수행하고 있다. 하지만 현재 5개 지역본부별로 나뉘어서 기능이 수행되고 있고, 사령의 경험에 의하여 수작업 형태로 이루어지고 있기 때문에 전체 시스템의 관점에서 보면 최적의 해소안이 도출되고 있지 못하다. 따라서 본 논문에서는 시스템을 전역적으로 고려하여 최적의 해소안을 제시하고자 한다. 또한 최적화의 개념을 도입하기 위하여 6가지의 가중치를 설정하고, 이 가중치를 고려한 지연시간의 합을 목적함수의 값으로 설정한다. 본 시스템은 이러한 가중치의 합을 최소로 하는 복수의 해소안을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.220-222
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• 1998

시간지원 데이터베이스 시스템은 각 데이터 항목에 대해 현재 비젼뿐만 아니라 이력 버전들까지도 관리하기 때문에 시간지원 트랜잭션은 기존 데이터베이스 시스템의 트랜잭션보다 더 많은 데이터 레코드들을 액세스한다. 그러므로, 시간지원 데이터베이스 관리 시스템은 시간지원 트랜젝션들간의 충돌을 최소의 비용으로 검출하면서도 시스템 전체 성능의 저하를 유발하는 거짓 충돌(false conflict)을 검출하지 않고 실제 충돌을 정확하고 효율적으로 검출할 수 있어야 한다. 본 논문에서는 시간지원 데이터베이스 시스템에서 동시적으로 실행되는 시간지원 트랜잭션들간의 효율적인 충돌 검출 기법으로서 2레벨 충돌 검출 기법을 제안하고, 모의 실험을 통하여 기존의 충돌 검출 기법들과 성능을 비교 분석하였다. 실험 분석의 결과로서 제안된 2레벨 충돌 검출 기법은 기존의 검출 기법들보다 동시적으로 실행되는 시간지원 트랜잭션들간의 충돌을 적은 비용으로 정확하게 검출할 수 있는 효율성이 입증되었다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.45-47
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• 1998

객체지향 데이터베이스 시스템에서 많이 연구되고 있는 묵시적 권한부여(implicit authorization) 방법은 모든 객체에 대하여 일일이 권한을 부여하는 오버헤드를 줄이기 위한 방법이다. 묵시적 권한부여 방법에서는 기존의 권한과 새로이 추가될 권한간의 충돌(conflict) 여부의 효율적인 검사가 중요하다. 기존의 데이터베이스 단위 계층 구조( database granularity hierarchy)에서의 의도형 권한부여(intention type authorization) 기법은 자신의 자손 노드에 대한 권한을 쉽게 판정할 수는 있지만, 클래스 복합 계층 구조(class composition hierarchy)상에서의 임의의 한 노드 ni에 추가로 권한을 부여할 때 ni의 자손 노드와 복합 참조(composite reference)의 관계를 가지는 노드 nj들에 대한 권한과의 충돌 여부를 탐지하기 위하여 추가로 nj들에 대한 권한을 일일이 탐색해야 하는 어려움이 있었다. 본 논문에서는 클래스 복합 계층 구조에서의 묵시적 권한부여 하에서 발생할 수 있는 권한간의 충돌을 효율적으로 탐지하는 새로운 기법을 확장하여 제안한다. 제안된 복합 계층 의도형 권한부여(intention type authorization for composition hierarchy)기법은 계층 구조에서 복합 참조의 관계를 따라 nj를 일일이 탐색할 필요 없이 노드 ni에서 바로 충돌 여부를 판정할 수 있는 장점을 가진다.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.1-8
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• 2008

This paper presents a real-time algorithm for collision detection, collision avoidance and guidance. Three-dimensional point-mass aircraft models are used. For collision detection, conflict probability is calculated by using the Monte-Carlo Simulation. Time at the closest point of approach(CPA) and distance at CPA are needed to determine the collision probability, being compared to certain threshold values. For collision avoidance, one of possible maneuver options is chosen to minimize the collision probability. For guidance to a designated way-point, proportional navigation guidance law is used. Two scenarios on encounter situation are studied to demonstrate the performance of proposed algorithm.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.49-63
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• 2008

RDF is the base ontology model which is used in Semantic Web defined by W3C. OWL expands the RDF base model by providing various vocabularies for defining much more ontology relationships. Recently Jain and Farkas have suggested an RDF access control model based on RDF triple. Their research point is to introduce an authorization conflict problem by RDF inference which must be considered in RDF ontology data. Due to the problem, we cannot adopt XML access control model for RDF, although RDF is represented by XML. However, Jain and Farkas did not define the authorization propagation over the RDF upper/lower ontology concepts when an RDF authorization is specified. The reason why the authorization specification should be defined clearly is that finally, the authorizatin conflict is the problem between the authorization propagation in specifying an authorization and the authorization propagation in inferencing authorizations. In this article, first we define an RDF access authorization specification based on RDF triple in detail. Next, based on the definition, we analyze the authoriztion conflict problem by RDF inference in detail. Next, we briefly introduce a method which can quickly find an authorization conflict by using graph labeling techniques. This method is especially related with the subsumption relationship based inference. Finally, we present a comparison analysis with Jain and Farkas' study, and some experimental results showing the efficiency of the suggested conflict detection method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.152-167
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• 2018

The high-speed weigh-in-motion system can collect the traveling speed and load information of individual vehicles, which can be used in a variety of ways for the traffic surveillance. However, it has a limit to apply the high-speed weigh-in-motion data directly to a safety analysis because high-speed weigh-in-motion's raw data are point measured data. In order to overcome this problem, this paper proposes a method to calculate the conflict rate and the Impulse severity based on surrogate safety measures derived from the detection time, detection speed, vehicle length, vehicle type, vehicle weight. It will be possible to analyze and evaluate the risk of rear-end collision on freeway traffic. In addition, this study is expected to be used as a fundamental for identifying crash risks and developing policies to enhance traffic safety on freeways.

• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.24-33
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• 2009

In patch-and-stitch localization algorithms, a flip error refers to the kind of error in which a patch is stitched to the map as being wrongly reflected. In this paper, we present an anchor-free localization algorithm which tries to detect and prevent flip errors. The flip error prevention is achieved by two filtering mechanisms: the flip-ambiguity test and the flip-conflict detection. We evaluate the performances of proposed techniques though simulations and show that they achieve significant performance improvements.