• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.26 no.2
• /
• pp.39-46
• /
• 2018

Departure Manager (DMAN) is a tool to optimize the departure sequence and to suggest appropriate take-off time and off-block time of each departure aircraft to the air traffic controllers. To that end, Variable Taxi Time (VTT), which is time duration of the aircraft from the stand to the runway, should be estimated. In this paper, a study for development of VTT prediction algorithm based on machine learning techniques is presented. The factors affecting aircraft taxi speeds were identified through the analysis of historical traffic data on the airport surface. The prediction model suggested in this study consists of several sub-models that reflect different types of surface maneuvers based on the analysis result. The prediction performance of the proposed method was evaluated using the actual operational data.

• Journal of KIISE:Information Networking
• /
• v.32 no.5
• /
• pp.551-560
• /
• 2005

To reduce the amount of the signaling messages occurred in movement, HMIPv6 has been introduced as the hierarchical mobility management architecture tor MIPv6 by regarding the locality of movements. When approaching the visited link, the authentication procedure should be done successfully prior to any motility support message exchanges. The AAA(Authentication, Authorization and Account) authentication service is applied gradually to the wireless LAN and Cellular networks. However, It may bring about the service latency for the sessions of requiring the real-time processing due to not providing the optimized signaling in local and frequent movements. In this paper, we propose the authentication architecture with 'delegation' scheme to reduce the amount of signaling message and latency to resume for local movements by integrating it with HMIPv6 architecture. We provide the integrated authentication model and analyze the performance and effectivity of our proposal and finally offer the analysis materials comparing to the exiting authentication scheme. It cuts down the cost to $33.6\%$ at average measurement.

• Spatial Information Research
• /
• v.18 no.4
• /
• pp.89-98
• /
• 2010

Recently, the target of navigation system is moving from the cars to pedestrians. Many researches are in progress regarding pedestrian navigation, However, in most cases, the path-finding is based on the existing node/link network model. which is widely used for the car navigation, and thus showing its limitation. The reasons arc that a) unlike with a car, the paths that pedestrians take arc not limited to the roads, b) pedestrians an~ not restricted in rotation or direction, and c) they can freely move within the walkable space. No alternatives have been offered yet, especially for openspaces such as a park or square. Therefore, in this research, we suggested appropriate methods to create paths that can be used in pedestrian navigation service, by using motion-planning technology, which is used in the field of robotics for planning the motion of an object, and conducted tests for their applicability.

• Proceedings of the Korean Society for Information Management Conference
• /
• 1994.12a
• /
• pp.29-32
• /
• 1994

과거 실세계 정보를 처리하기 위한 방법으로는 관계형데이타베이스, 객체지향데이타베이스. 지식베이스시스템 등이 연구되었다. 이들 방법은 제한된 정보표현 및 정보의 운영 및 접근방법 등의 문제점을 갖는다. 정보의 구조화는 정보의 의미를 분석하고 정보의 특성에 적합한 융통성 있는 정보모델을 필요로 한다. 본 논문에서는 방대한 양의 정보처리 및 다양한 형태의 표현, 동적 변환 등의 정보특성을 효율적으로 처리하기 위한 정보모델로 의미구조그래프를 사용하여 기존 시스템의 문제점을 해결하기 위한 방법을 제안한다. 의미구조그래프를 사용한 정보구조화는 정보의미를 분석할 수 있으며, 정보의 표현의 융통성을 제공한다. 의미구조그래프는 노드와 링크를 갖는 확장된 하이퍼그래프를 사용하였으며, 정보구조화를 위한 대상데이타로 문화예술 분야의 관련 정보를 실험하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04b
• /
• pp.693-695
• /
• 2000

WBI는 시간과 공간의 제약 없이 다양한 교수 전략의 구사와 실감나는 교육매체의 활용을 가능하게 하여, 교사-학습자 또는 학습자-학습자 상호간의 교육 교육효과를 증진시킬 수 있는 환경을 제공한다. 그러나 WBI는 하이퍼텍스트의 링크로 연결된 일차원적 가상공간에 실시되므로 학습자의 인지적 부하를 가중시키고 학습방향 상실의 문제점을 야기시킨다. 따라서 본 논문에서는 이러한 문제점들을 해결하기 위하여 동적 학습공간 모델을 제시하고 이를 구현하였다. 동적 학습공간 모델은 전체 학습공간이 투명하게 지도(Hpyper-Map)형태로 나타나고 공간 노드간의 관계가 명확하여, 학습 위치와 내용을 확실하게 파악할 수 있다. 또한 학습공간이 학습자에 의해 자발적으로 구성됨에 따라, 학습자 수준별 열린 학습이 가능하고, 학습 구성 능력을 신장시켜 학습의 주도권을 주체적으로 행사할 수 있도록 하는 창조적 학습 분위기를 조성할 수 있다.

• Spatial Information Research
• /
• v.14 no.2 s.37
• /
• pp.245-260
• /
• 2006

A practical use of the location information and user requirement are increased in a mobile environment which supports the portability. And Various service which GIS is related with a Spatial DB have been processed. Generally, logical relation of a traffic network which organizes the Road DB uses a basic node-link structure. In this way, Designed structure can not be flexible at various model apply and are not efficient with a database retrieval in a maintenance management side. In this research, We supplement with the problem of a existing network model and the limitation of the building through the design of a network model which uses dynamic segmentation. And we tried to implement efficient hierarchy model at the retrieval of the network and presentation. Designed model supports a stage presentation of various level and a hierarchy entity relation and We are expected to supplement a network spatial modelling function which the GIS has.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.2
• /
• pp.39-57
• /
• 2018

The purpose of this study was to construct an artificial intelligence model that learns and estimates the relationship between vehicle queue length and link travel time in urban areas. The vehicle queue length estimation model is modeled by three models. First of all, classify whether vehicle queue is a link overflow and estimate the vehicle queue length in the link overflow and non-overflow situations. Deep learning model is implemented as Tensorflow. All models are based DNN structure, and network structure which shows minimum error after learning and testing is selected by diversifying hidden layer and node number. The accuracy of the vehicle queue link overflow classification model was 98%, and the error of the vehicle queue estimation model in case of non-overflow and overflow situation was less than 15% and less than 5%, respectively. The average error per link was about 12%. Compared with the detecting data-based method, the error was reduced by about 39%.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.996-1000
• /
• 2009

물순환계를 종합적으로 관리하기 위해서는 물순환계의 모니터링과 해석모형의 구축이 필요하다. 실측자료만으로는 복잡 다양한 물순환계 구조 및 인과관계를 규명할 수 없기 때문에 시간적 공간적으로 변화하는 다양한 수문현상을 일관된 하나의 시스템으로 이해하기 위해 물순환 해석모델을 구축하여 검토할 필요가 있다. CAT(Catchment hydrologic cycle Analysis Tool)은 수문학적으로 균일하게 판단되는 범위를 소유역으로 분할하여 지형학적 요인에 의한 유출 특성을 객관적으로 반영할 수 있게 하며, 토양층에 따라 침투, 증발, 지하수 흐름 등의 모의가 가능하도록 하는 Link-Node 모형으로, 증발산은 기준 증발산을 외부에서 직접 입력하거나, Penman-Monteith 방법을 선택할 수 있으며, 침투는 토양의 수리전도도에 따른 연직방향 침투 및 사면방향 복귀류를 고려할 수 있다. 노드의 지하수 유거를 고려하여 기존 노드-링크 방식 모형의 장기 유출 해석시 제한점을 보완하였으며, Muskingum, Muskingum-Cunge, Kinematic wave 방법을 이용하여 하도추적을 모의할 수 있다. 또한 GUI를 통해 사용자가 손쉽게 모형을 적용하고 관리 할 수 있도록 하고, 여러 시나리오를 적용함에 있어서 편리하도록 개발 중인 모형이다. 본 연구에서는 개발중인 CAT 모형을 평가 하기위해 시험 유역으로 운영 중인 설마천 유역에 적용하여 소유역 분할(노드수), 계산 시간 간격(일/시단위) 등에 따른 적용성을 평가하였다. 관측 자료를 통해 구축 가능한 물리적 매개변수를 통해 해당 유역을 단일 노드 및 다중 노드로 간단히 모형화할 수 있었으며, 모의 결과, 관측 유량과 적절히 일치하는 결과를 얻을 수 있었다. 1시간 단위에 대한 모의에서도 유출을 적절히 모의할 수 있었으며, 소규모 유역에 대한 정밀한 물순환 해석이 가능할 것으로 평가되었다.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.11
• /
• pp.57-65
• /
• 2014

This paper presents a framework that is based on a reconfigurable macro-model of current-mode logic (CML) high-speed digital circuits enabling equation-based design optimization. The proposed macro-model is compatible with geometric programming, thereby enabling constraint-driven top-level power optimization. The proposed optimization framework is applied to a design of CML based serial-link transmitter with user-defined design specifications as an example of high speed digital circuits using 45nm and 90nm CMOS technology. The proposed optimization framework can derive a design with optimal power efficiency for given transistor technology nodes.

• Korean Journal of Cognitive Science
• /
• v.13 no.1
• /
• pp.13-21
• /
• 2002

Fuzzy logic ignores some information in the reasoning process. Neural network is powerful tools for the pattern processing, but, not appropriate for the logical reasoning. To model human knowledge, besides pattern processing capability, the logical reasoning capability is equally important. Another new neural network called neural logic network is able to do the logical reasoning. Because the fuzzy inference is a fuzzy logical reasoning, we construct fuzzy inference network based on the neural logic network, extending the existing rule-inference network. And the traditional propagation rule is modified. Experiments are performed to compare search costs by sequential searching and searching by priority. The experimental results show that the searching by priority is more efficient than the sequential searching as the size of the fuzzy inference network becomes larder and an the number of searching increases.