• Proceedings of the KOR-KST Conference
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• 1996.12a
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• pp.81-108
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• 1996

첨단교통정보시스템(ATIS)의 핵심 요소라 할 수 있는 동적경로안내 시스템(Dynamic Route Guidance System : DRGS)은 운전자가 목적지에 도착하기까지 실시간 교통정보를 토대로 최적경로를 안내해 줌으로써 날로 심화되어 가고 있는 교통혼잡을 최소화할 수 있으리라 기대를 모으고 있다. 특히 교통사고나 긴급도로공사 등으로 인해 발생하는 돌발적 교통혼잡하에서는 DRGS의 역할이 더욱 커질 것으로 예상되고 있다. 본 논문은 돌발적 교통혼잡하에서 보다 효과적인 DRGS의 경로 안내 알고리즘을 개발하는 데 그 목적이 있다. 이를 위해서 우선 하부구조기반(Infrastructure Based) DRGS와 개인차량기반(In-vehicle Based)DRGS의 장단점을 운전자, 교통행정당국, 그리고 교통체계관점에서 비교하였고, 시스템 아키텍쳐와 경로안내 알고리즘간의 상호관계를 규명하였다. 또한 효율적인 경로안내를 위해 사용자 평형(User Equilibrium)경로안내전략과 시스템최적화(System Optimal) 경로안내전략을 이상형 교통망(Idealistic Network)을 통해 비교분석하였다. 여기에는 현재 ITS-America에서 System Architecture 평가를 위해 사용한 INTEGRATION이라는 ITS Simulation Model과 그 통행저항함수를 사용하였다. 이를 토대로 돌발적 교통혼잡상황 아래서 사용자평형 경로안내를 제공할 경우 야기될 수 있는 Braess` Paradox 문제와, 총통행시간을 최소화하기 위한 시스템최적 경로안내를 제공할 경우 일어날 수 있는 사용자 호응도(User Compliance)문제를 동시에 고려한 적응형 동적경로안내 알고리즘을 개발하였다. 여기에는 돌발적 교통혼잡하에서 통행시간을 동적으로 예측하기 위해 이산형 확정적 대기행렬모형(Discrete Deterministic Queueing Model)이 사용되었다. 한편 알고리즘의 효율성을 평가하기 위해 이상형 교통망과, 실제 미국 Virginia 주의 Fairfax County에 소재한 주간 고속도로 66번(I-66)과 인접 교통망의 교통자료를 사용하여 각종 돌발교통 혼잡 상황을 전제로 한 Traffic Simulation과 정보제공시나\리오를 INTEGRATION Model을 이용해 실행하였다. 그 결과 적응형 알고리즘이 개개인의 최단시간 경로를 제공하는 사용자 평형 경로안내전략에 비해 교통혼잡도와 정체시간의 체류정도에 따라 3%에서 10%까지 전체통행시간을 절약할 수 있다는 결론을 얻었다.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.1
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• pp.136-142
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• 2007

This paper proposes a new approach on nonlinear maneuvering target tracking. In this paper, proposed algorithm is the Kalman filter based on the adaptive interactive multiple model using the concept of predicted impact point and utilize modified Kalman filter regarding the error between measurement position and predicted impact point. The unknown target acceleration is regarded as an additional process noise to the target model, and each sub-model is characterized in accordance with the valiance of the overall process noise which is obtained on the basis of each acceleration interval. To compensate the decreasing performance of Kalman filter in nonlinear maneuver, we construct optional algorithm to utilize proposed method or Kalman filter selectively. To effectively estimate the acceleration during the target maneuvering, the rapid increase of the noise scale is recognized as the acceleration to be used in maneuvering target's movement equation. And a few examples are presented to show suggested algorithm's executional potential.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.132-136
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• 2007

최근 지구온난화로 인한 이상기후의 영향으로 강우일수는 줄고 있으나 강수량은 예년과 비슷한 수준을 보이고 있다. 이로 인해 갈수기의 용수부족 현상은 더욱 심해지고. 장마철의 홍수피해와 게릴라성 집중호우로 인한 피해가 커지는 등 해가 갈수록 홍수 예경보의 중요성은 더욱 높아지고 있다. 그럼에도 불구하고 현재 홍수 예경보 체계는 몇 가지 문제를 가지고 있다. 기존 예경보 체계의 경우 한 번의 예측을 수행하기 위해 수반되는 전처리과정과 주계산과정을 거치는 동안 각 과정에서 발생한 오차들이 반복, 누적되어 최종 결과물(예측된 유출량) 속에 모두 포함된다. 또한 기존 체계에서는 유출모형을 적용하기 위해서 토양형. 피복상태 등에 관련된 매개변수들이 필요한데. 이러한 매개변수의 결정에 어려움이 있고. 불확실성을 갖고 있다. 본 연구에서는 불확실성을 적극적으로 인정하고 수학적으로 해석하려는 fuzzy 이론을 신경망 이론에 도입하여 홍수 예경보 시스템의 운영과정에서 발생하는 불확실성의 문제를 해결하고자 하였다. 본 연구에서 사용한 ANFIS(Adaptive Neuro-Fuzzy Inference System)은 data driven model(자료에 기반을 둔 모형)의 하나로 다음과 같은 장점을 가진다. 우선 data driven model은 유역의 물리적, 지형적 특성을 고려하지 않고(매개변수설정에서 발생하는 문제 해결 가능), 입력자료와 출력자료만을 고려하여 구축되는 모형이므로, 유역의 물리적 자료나 지형 자료와 같은 방대한 양의 자료 수집이 필요 없고, 일단 모형이 구축되면 자료의 입력만으로도 신뢰성 높은 결과를 단시간 내에 효율적으로 획득할 수 있다. 그리고 유역 내의 상황이 변화하더라도, 이들의 영향을 고려하여 쉽게 모형을 갱신할 수 있다. 마지막으로 모형의 구축 과정이 물리적 모형에 비해 비교적 간편하다는 장점이 있다. 본 연구에서는 ANFIS를 통해 탄천유역의 강수량 자료와 대곡교의 수위자료를 입력자료로 사용하여 대곡교의 수위를 예측하였다. 입력 자료는 시간차 계열의 강우량과 수위 자료를 사용하였으며 모형을 통하여 t+1, t+2, t+3 시간 후의 수위를 예측하였다.

• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.155-167
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• 2007

There are four types of human beings according to the Sasang Typology, Oriental medical doctors frequently prescribe healthcare information and treatment depending on one's type, The feature ratios (Table 1) on the human face are the most important criterions to decide which type a patient is. In this paper, we proposed a system to extract these feature ratios from the people's side face, There are two challenges in acquiring the feature ratio: one that selecting representative features; the other, that detecting region of interest from human profile facial image effectively and calculating the feature ratio accurately. In our system, an adaptive color model is used to separate human side face from background, and the method based on geometrical model is designed for region of interest detection. Then we present the error analysis caused by image variation in terms of image size and head pose, To verify the efficiency of the system proposed in this paper, several experiments are conducted using about 173 korean's left side facial photographs. Experiment results shows that the accuracy of our system is increased 17,99% after we combine the front face features with the side face features, instead of using the front face features only.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.4
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• pp.117-125
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• 2012

Although many studies have been conducted to extract buildings from airborne lidar data, most of them assume that all the boundaries of a building are straight line segments. This makes it difficult to model building boundaries containing curved segments correctly. This paper aims to model buildings containing curved segments as combination of straight lines and arcs. First, two sets of boundary points are extracted by adaptive convex hull algorithm and local convex hull algorithm with a larger radius. Then, arc segments are determined by average spacing of boundary points and intersection ratio of perpendicular lines. Finally, building boundary is modeled through regularization of least squares line or circle fitting. The experimental results showed that the proposed method can model the curved building boundaries as arc segments correctly by completeness of 69% and correctness of 100%. The approach will be utilized effectively to create automatically digital map that meets the conditions of the Korean digital mapping.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.7-15
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• 2005

Numerical analysis model is proposed to predict the dynamic behavior of a single-degree-of-freedom structure that is equipped with hybrid base isolation system. Hybrid base isolation system is composed of friction pendulum systems (FPS) and a magnetorheological (MR) damper. A neuro-fuzzy model is used to represent dynamic behavior of the MR damper. Fuzzy model of the MR damper is trained by ANFIS (Adaptive Neuro-Fuzzy Inference System) using various displacement, velocity, and voltage combinations that are obtained from a series of performance tests. Modelling of the FPS is carried out with a nonlinear analytical equation that is derived in this study and neuro-fuzzy training. Fuzzy logic controller is employed to control the command voltage that is sent to MR damper. The dynamic responses of experimental structure subjected to various earthquake excitations are compared with numerically simulated results using neuro-fuzzy modeling method. Numerical simulation using neuro-fuzzy models of the MR damper and FPS predict response of the hybrid base isolation system very well.

• International Journal of Concrete Structures and Materials
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• v.11 no.1
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• pp.135-149
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• 2017

The prediction of the actual ultimate capacity of confined concrete columns requires partial confinement utilization under eccentric loading. This is attributed to the reduction in compression zone compared to columns under pure axial compression. Modern codes and standards are introducing the need to perform extreme event analysis under static loads. There has been a number of studies that focused on the analysis and testing of concentric columns. On the other hand, the augmentation of compressive strength due to partial confinement has not been treated before. The higher eccentricity causes smaller confined concrete region in compression yielding smaller increase in strength of concrete. Accordingly, the ultimate eccentric confined strength is gradually reduced from the fully confined value $f_{cc}$ (at zero eccentricity) to the unconfined value $f^{\prime}_c$ (at infinite eccentricity) as a function of the ratio of compression area to total area of each eccentricity. This approach is used to implement an adaptive Mander model for analyzing eccentrically loaded columns. Generalization of the 3D moment of area approach is implemented based on proportional loading, fiber model and the secant stiffness approach, in an incremental-iterative numerical procedure to achieve the equilibrium path of $P-{\varepsilon}$ and $M-{\varphi}$ response up to failure. This numerical analysis is adapted to assess the confining effect in rectangular columns confined with conventional lateral steel. This analysis is validated against experimental data found in the literature showing good correlation to the partial confinement model while rendering the full confinement treatment unsafe.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.304-309
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• 2007

What is important in ubiquitous computing is collecting users' context information from various sensors and providing services suitable for use's current situation. Particularly in mobile environment, each area has different context awareness structure and this makes it difficult to share information with other areas. As a result, context resources for recognizing users' context ate insufficient. Moreover, because mobile devices have a limited processing capacity, there are difficulties in the real time analysis of users' context. This paper proposed a context awareness and integration model for analyzing users' context actively and providing adaptive services using mobile devices. The proposed model distinguishes users' context between dynamic and static structure to analyze the context, and obtains context resources by sharing context information of users within an area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1199-1204
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• 2011

The capability to bilaterally telemanipulate soft-tissues for medical applications could increase the quality of telemanipulation systems. Since most soft-tissue manipulation tasks include constrained motion interacting with an unknown and dynamic bioenvironment through contact, bilateral telemanipulation raises problems due to stability and transparency issues. It is well understood that knowledge of environments plays an important role in pursuing transparent telemanipulation and achieving telepresence, and in particular, online estimation of environmental parameters with an explicit environment model can improve these systems' performance. In this study, a continuum mechanics-based environment model with an online environmental property estimation algorithm and an adaptive telemanipulation control scheme is proposed. The proposed method can improve the telemanipulation performance in terms of stability and transparency and can offer valuable information (e.g., elastic modulus of soft tissues) pertaining to diagnostic examinations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.90-97
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• 2009

The advantages of the orthogonal frequency division multiplexing (OFDM) are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. To further utilize vast channel capacity of the multiuser OFDM, one has to find the efficient adaptive subchannel and bit allocation among users. In this paper, we propose an 0-1 integer programming model formulating the optimal subchannel and bit allocation problem of the multiuser OFDM. We employ a dual-decomposition method that provides a tight linear programming (LP) relaxation bound. Simulation results are provided to show the effectiveness of the 0-1 integer programming model. MATLAB simulation on a system employing M-ary quardarature amplitude modulation (MQAM) assuming a frequency-selective channel consisting of three independent Rayleigh multi-paths are carried with the optimal subchannel and bit allocation solution generated by 0-1 integer programming model.