• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.83-90
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• 2011

The evaluation of Conflict detection and Resolution Algorithms require the use of analytical that describe encounter flight safety and the costs and benefits of optimization maneuver. A number of such algorithms have been applied in the past to the free flight. Each algorithm has benefits and limitations, and flight safety may be facilitated by combining the best features of various techniques. This paper studied a summary of conflict detection and resolution algorithm approaches. Algorithm techniques are categorized and the fundamental assumptions, capabilities, and limitations of each approach are described. The Algorithms are evaluated and compared based on their applicability to free flight airspace conflict situations.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.3
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• pp.27-33
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• 2010

The goal for the CD&R system is to predict that a conflict is going to occur in the future, communicate the detected conflict to a human operator, and, in some cases, assist in the resolution of the conflict situation. To provide insight into different methods of conflict detection and resolution, a literature review of previous research models and current developmental and operational systems was performed. This paper focuses only on the specific attributes of each model, not on the depth to which a model has been analyzed, validated, or accepted. Thus, care should be taken to remember that a model that seems to be simple according to our categorization scheme may be significantly more viable than an apparently sophisticated model.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.37-45
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• 2009

A method of conflict detection and resolution is described by using simple geometric approach. Two VAVs are dealt with and considered as point masses with constant velocity. This paper discusses en route aircraft which are assumed to be linked by real time data bases like ADS-B. With this data base, all DAVs share the information each other. Calculating PCA (Point of Closest Approach), we can evaluate the worst conflict condition between two VAVs. This paper proposes one resolution maneuvering logic, which can be called 'Vector Sharing Resolution'. In case of conflict, using miss distance vector in PCA, we can decide the directions for two VAVs to share the conflict region. With these directions, VAVs are going to maneuver cooperatively. First of all, this paper describes some '2-D' conflict scenarios and then extends to '3-D' conflict scenarios.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.71-76
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• 2004

In this paper, we propose a pilot study to deploy the Railway Conflict Detection and Resolution System(RCDRS) in the context of Korean Railway(KORAIL). KORAIL plans to deploy in near future RCDRS, which is a decision support module placed on the top level of the Railway Traffic Management System(RTMS). This study entails the review of the state-of-art researches and projects in the field of the railway traffic management, as well as the analysis of the traffic characteristics of the major railroad lines in KORAIL. The analysis provides a basis to choose a solution approach for the railway conflict detection and resolution problem that each individual line faces. This study plays a role as a pilot study for a full systematic approach, in which interactions between lines require further advanced analysis to take the entire KORAIL lines into consideration rather than a myopic approach.

• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.1-7
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• 2019

Thisstudy presentsthe development of a fast-time airport surface simulator. The simulator usesthe output from a first-come first-served (FCFS) scheduler and has adopted one-dimensional dynamic model to simulate the movement of the aircraft on the surface. Higher collision risks situations in the airport surface traffic are analyzed to classify those situations into six cases. A conflict detection and resolution algorithm is implemented to maintain separation distance and to prevent deadlock. The simulator was tested with a scenario at the Incheon International Airport that contains 72 aircraft. Without the conflict detection and resolution, various conflict situations are identified. When the conflict detection and resolution algorithm is managing the traffic, it is confirmed that the conflicts are removed at the price of additional delays. In the conflict resolution algorithm, three prioritization strategies are implemented, and delayed aircraft count and average additional delays are compared. Prioritization based on remaining time or distance showed smaller total additional delay compared to choosing minimum delay priority for each situation.

• IE interfaces
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• v.23 no.1
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• pp.24-34
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• 2010

In the telecommunication system which is based on the existing PSTN(public switched telephone network), feature interaction has been an important research issue in order to provide seamless services to users. Recently, rapid proliferation of IP-based network and the various types of IP media supply services, the feature interaction from the perspective of application services has become a significant aspect. This paper presents conflict detection and resolution algorithms for designing and operating a variety of services that are provided through IP-based network. The algorithms use explicit service interactions to detect conflicts between a new service and registered services. They then apply various rules to reduce search space in resolving conflicts. The algorithms are applied to a wide range of realistic service provision scenarios to validate that it can detect conflicts between services and resolve in accordance with different rule sets. By applying the algorithms to various scenarios, it is observed that the proposed algorithms can be effectively used in operating an IP-based services network.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.179-185
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• 2007

In large station with high density traffic, trains can be hardly controlled by CTC but by station dispatcher because CTC has difficulties in monitoring all states of affairs happening within each station such as departures, arrivals of many trains from different lines and shunting of trains to move between yards and platforms, etc. Therefore the station's dispatcher has to make quick decision about how to reschedule the times and routes for all the trains scheduled within a specific time window. And such decision becomes harder when an unexpected delay occurs because a delay occurring in a train propagates other trains as time goes on. Generally, it is called the conflict detection and resolution to adjust beforehand the distorted schedule due to a delay to original schedule. Our research is different from the state of the arts in that ours determines simultaneously the routes and the times of arrival and departure of trains, although others do only the arrival and departure time of the trains without considering the alternative routes and shunting of the station. This study suggests a mathematical approach for how to detect in advance and resolve efficiently the conflicts occurring within a station and it will be shown how to reduce delay using our approach by means of analysing the schedule of ChyungRyangRi station.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.619-629
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• 2015

The train conflict resolution problem refers to an adjustment of the train operation schedule in order to minimize the delay propagation when a train conflict is predicted or when a train conflict occurs. Previous train studies of train conflict resolutions are limited in terms of the size of the problems to be solved due to exponential increases in the variables. In this paper, we propose a train conflict resolution model using a time-space network to solve the train conflict situation in the operational phase. The proposed model adjusts the size of the problem by giving only the dwell tolerance in the time-space network only for stops at the station after a train conflict. In addition, the proposed model can solve large problems using a path flow variable. The study presents a train delay propagation analysis and experimental results of train conflict resolution assessments as well using the proposed model.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.687-694
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• 2008

Given the daily tactical schedule, the purpose of the traffic management system is to develop operating plan that will achieve the stated schedule as best as possible. The operating plan has to be modified during the day because of occurring disturbance(e.g. delay, infrastructure breakdown, etc.) Conflict detection and resolution(CDRS) are aimed for adjusting the distorted schedule to tactical schedule. Our research separate CDRS into two hierarchy modules, line conflict control module and station conflict control module. We define the role of each modules and design the cooperative architecture. We suggest the conflict detection and resolution approach based on mathematical model. These results can be implemented as prototype modules.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.190-203
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• 2003

열차경합의 사전검지 및 해소 시스템(Railway Conflict Detection and Resolution System, RDCRS)은 열차운행관리 시스템(Railway Traffic Management System, RTMS)의 최상위 의사결정지원 모듈이다. 본 논문에서는 한국철도에서 RCDRS의 필요성과 국외 적용현황 및 기존 연구현황을 분석한다. 또 RCDRS를 한국철도에 적용하기 위한 전반적인 방안을 한국철도 주요 노선별 열차운영 여건을 고려하여 제시한다. 또, 철도청에서 실시하는 '사령실 통합 신호설비 시설' 사업에 관한 RCDRS의 1단계 적용방안을 제시한다.