• 한국게임학회 논문지
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• 제18권5호
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• pp.123-132
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• 2018

실시간 그래픽스 응용에서 연체의 움직임을 효율적으로 생성하기 위해 다양한 방법이 제안되었다. 연체 구성 요소들의 위상을 유지하기 위해서는 서로를 묶는 힘이 존재할 수밖에 없으며, 이는 강직도(stiffness)로서 수치적분의 시간간격의 크기를 제한하고 효율성을 떨어트린다. 이를 해결하기 위해 시간간격을 늘릴 수 있는 암시적 적분이 제안되었지만, 대규모 행렬이 포함된 선형시스템을 풀어야 해서 계산복잡도가 크게 높아진다. 이 문제를 개선한 근사 기법들은 댐핑 효과의 증가와 정확성의 손실을 초래할 수밖에 없다. 본 논문에서는 선형시스템을 풀지 않고도 안정성은 크게 높이기 위해 조화진동에 근거하여 스프링 힘을 적분하고, 이를 근사 암시적 기법과 결합하여 안정성을 극대화 하는 방법을 제안한다. 이 기법은 GPU를 통한 병렬화가 용이하여 거대한 규모를 가진 연체 객체의 움직임을 실시간에 생성할 수 있다.

• Computers and Concrete
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• 제20권4호
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• pp.391-407
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• 2017

Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and especially in corrosive environments to improve the durability of concrete structures. However, FRPs have a low modulus of elasticity and a linear elastic behavior up to rupture, thus reinforced concrete (RC) components with such materials would exhibit a less ductility in comparison with steel reinforcement at the similar members. There were several studies showed the behavior of concrete beams with the hybrid combination of steel and FRP longitudinal reinforcement by adopting the experimental and numerical programs. The current study presents a numerical and analytical investigation based on the data of previous researches. Three-dimensional (3D) finite element (FE) models of beams by using ANSYS are built and investigated. In addition, this study also discusses on the design methods for hybrid FRP-steel beams in terms of ultimate moment capacity, load-deflection response, crack width, and ductility. The effects of the reinforcement ratio, concrete compressive strength, arrangement of reinforcement, and the length of FRP bars on the mechanical performance of hybrid beams are considered as a parametric study by means of FE method. The results obtained from this study are compared and verified with the experimental and numerical data of the literature. This study provides insight into the mechanical performances of hybrid FRP-steel RC beams, builds the reliable FE models which can be used to predict the structural behavior of hybrid RC beams, offers a rational design method together with an useful database to evaluate the ductility for concrete beams with the combination of FRP and steel reinforcement, and motivates the further development in the future research by applying parametric study.

• 전기학회논문지
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• 제60권2호
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• pp.398-406
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• 2011

In this paper, we introduce a new architecture of PSO-based Polynomial Neural Networks (PNN) and discuss its comprehensive design methodology. The conventional PNN is based on a extended Group Method of Data Handling (GMDH) method, and utilized the polynomial order (viz. linear, quadratic, and modified quadratic) as well as the number of node inputs fixed (selected in advance by designer) at Polynomial Neurons located in each layer through a growth process of the network. Moreover it does not guarantee that the conventional PNN generated through learning results in the optimal network architecture. The PSO-based PNN results in a structurally optimized structure and comes with a higher level of flexibility that the one encountered in the conventional PNN. The PSO-based design procedure being applied at each layer of PNN leads to the selection of preferred PNs with specific local characteristics (such as the number of input variables, input variables, and the order of the polynomial) available within the PNN. In the sequel, two general optimization mechanisms of the PSO-based PNN are explored: the structural optimization is realized via PSO whereas in case of the parametric optimization we proceed with a standard least square method-based learning. To evaluate the performance of the PSO-based PNN, the model is experimented with using Gas furnace process data, and pH neutralization process data. For the characteristic analysis of the given entire data with non-linearity and the construction of efficient model, the given entire system data is partitioned into two type such as Division I(Training dataset and Testing dataset) and Division II(Training dataset, Validation dataset, and Testing dataset). A comparative analysis shows that the proposed PSO-based PNN is model with higher accuracy as well as more superb predictive capability than other intelligent models presented previously.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.233-240
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• 2012

The implementation of business process management (BPM) systems in large number of business organizations transforms BPM system into such a level of maturity and tends to collect large repositories of business process (BP) models. This issue encourages BP flexibility that leads to a large number of process variants derived from the same model, but differing in structure, to be stored in the large repositories of BP models. Therefore, the repositories may include thousands of activities and related business objects with variation of requirements and quality of service. It is a common practice to customize processes from reference processes or templates in order to reduce the time and effort required to design and deploy processes on all levels. In order to address redundancy and underutilization problems, a generic process model, called as reference BP, is absolutely necessary to cover the best of process variants. This study aims to develop multiple-objective business process genetic algorithm (MOBPGA) to find a set of non-dominated (Pareto) solutions of business reference model to enhance conventional approach which considered only a single objective on creating BP reference model by using proximity score measurement. A mixed-integer linear program is constructed to evaluate performance of the proposed MOBPGA on small-scale problems by using standard measures for multiple-objective techniques. The results will show the viability of applying MOBPGA in terms of simultaneously maximizing proximity score measurement, minimizing total duration, and total costs of the selected reference model.

• 한국조경학회지
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• 제29권1호
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• pp.67-79
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• 2001

The purpose of this research is to evaluate the biotope value in a metropolitan area after constructing the biotope evaluation model to develop biotope networking in the light of ecological landscape planning. In addition this study is to provide a basic frame of constructing the biotope networking system in the future with the evaluation results. The scope of this research is limited to high density residential area including some part of the forest adjacent to urban boundary. The results of the classified biotope in the research area have been turned out to be 24 patterns. According to the result of estimated nature value having the forth grade, three were forests combined with urban natural parks, schools near forests, and grasslands. There is a little place having first grade. We an deduce this fact that we have surveyed biotopes, having the minimum nature value and wider than children's park. As for the result of evaluated the structure, there were the forests of Seong-Dong, Meaho-Dong, and Kumho river, which is the forth grade. As for the evaluation of connection-function, the followings area were evaluated as the third grade-linear biotopes having highly valued and sustainable similarity - Seoul-Pusan Railroad, Dong-Daegu St., Kumho river, river basins. Bum대 park and a botanic park near Suesung lake, As for the evaluated the buffer-function, higly valued production biotopes, existing at a transition belt between he residential density areas, are Sawol-Dong, Meaho-Dong and Kumho river. When each of the indexes was evaluated, the core of the biotop contained most of natural biotopes. Large artificial biotopes were evaluated as an important biotopes, while small artificial biotopes were classified as a dot biotope. The future research on the concrete biotope networking construction, based upon performed evaluation in this research, should be conducted.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.9-14
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• 2006

This paper develops a complete methodology for the mitigation of ionosphere spatial anomalies by GBAS systems fielded in the Conterminous U.S. (CONUS). It defines an ionosphere anomaly threat model based on validated observations of unusual ionosphere events in CONUS impacting GBAS sites in the form of a linear ‘wave front’ of constant slope and velocity. It then develops a simulation-based methodology for selecting the worst-case ionosphere wave front impact impacting two satellites simultaneously for a given GBAS site and satellite geometry, taking into account the mitigating effects of code-carrier divergence monitoring within the GBAS ground station. The resulting maximum ionosphere error in vertical position (MIEV) is calculated and compared to a unique vertical alert limit, or $VAL_{H2,I}$, that applies to the special situation of worst-case ionosphere gradients. If MIEV exceeds $VAL_{H2,I}$ for one or more otherwise-usable subset geometries (i.e., geometries for which the 'normal' vertical protection level, or $VPL_{H0}$, is less than the 'normal' VAL), the broadcast ${\sigma}_{pr_{-}gnd}$ and/or ${\sigma}_{vig}$ must be increased such that all such potentially-threatening geometries have VPL$_{H0}$ > VAL and thus become unavailable. In addition to surveying all aspects of the methods used to generate the required ${\sigma}_{pr_{-}gnd}$ and ${\sigma}_{vig}$ inflation factors for CONUS GBAS sites, related methods for deriving similar results for GBAS sites outside CONUS are suggested.

• 한국정보통신학회논문지
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• 제18권3호
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• pp.503-509
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• 2014

본 논문에서는 이동 로봇의 군집 제어를 위해 실시간 적응 신경 회로망 보상기를 갖는 PID 제어기를 제안한다. 전체 제어 시스템은 선도-추종 로봇 접근법에 의한 기구학 제어기와 이동 로봇의 동역학을 고려한 동적 제어기로 구성되어 있다. 동적 제어기는 PID 제어기에 동특성 변화를 보상하고 성능을 개선시키기 위해 실시간 학습 기능을 가진 신경 회로망 보상기로 구성하였다. 모의실험을 통해 원형 궤적과 직선 궤적에 대해 PID 제어기와 신경 회로망 보상기의 성능을 비교하였다. 이를 통해 실시간 학습 기능을 가진 신경 회로망 보상기가 PID 제어기의 성능을 향상시킴으로써 군집 제어에서 추종 로봇의 추종 성능을 향상시키는 것을 확인하였다.

• 정보처리학회논문지B
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• 제12B권7호
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• pp.795-802
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• 2005

본 논문에서는 일곱 가지의 기본적인 감정 정보를 자동으로 파악하고 얼굴을 PDA 상에서 렌더링할 수 있는 얼굴 표정의 인식 및 합성 시스템을 제시한다. 얼굴 표정 인식을 위해서 먼저 카메라로부터 획득한 영상으로부터 얼굴 부분을 검출한다. 그리고 나서 기하학적 또는 조명으로 인한 보정을 위해 정규화 과정을 거친다. 얼굴 표정을 분류하기 위해서는 Gabor wavelets 방법을 enhanced Fisher 모델과 결합하여 사용할 때가 가장 좋은 결과를 보였다. 본 표정 분류에서는 일곱 가지 감정 가중치가 결과로 제시되고, 그러한 가중 정보는 모바일 네트웍을 통하여PDA 상으로 전송되어 얼굴 표정 애니메이션에 이용되어진다. 또한 본 논문에서는 고유한 얼굴 캐릭터를 가진 3차워 아바타를 생성하기 위하여 카툰 쉐이딩 기법을 채택하였다. 실험 결과 감정 곡선을 이용한 얼굴 표정 애니메이션은 선형 보간법 보다 감정 변화의 타이밍을 표현하는데 더 효과적인 것으로 나타났다.

• Journal of Power Electronics
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• 제15권1호
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• pp.190-201
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• 2015

This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.

• 정보처리학회논문지D
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• 제9D권4호
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• pp.603-612
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• 2002

소프트웨어공학에서 소프트웨어 측정분야는 30년 이상 수많은 연구가 있어 왔으나 아직까지 구체적인 소프트웨어 개발노력과 비용 추정 모델이 거의 없는 실정이다. 만약 소프트웨어 개발노력과 비용을 측정하려면 소프트웨어 규모를 추정해야 한다. 소프트웨어의 규모를 측정하기 위한 많은 소프트웨어 척도가 개발되었지만 가장 일반적인 척도가 LOC(line of code)와 FPA(Function Point Analysis)이다. FPA는 소프트웨어 규모를 측정하는데 LOC를 사용할 때의 단점을 극복할 수 있는 기법이다. 본 논문은 FP(Function Point)로 측정된 소프트웨어 규모로 소프트웨어 개발노력을 추정하는 단순회귀모델을 제안한다. 실험에 사용된 데이터들은 다양한 개발환경과 개발방법을 적용한 최근의 789개 소프트웨어 개발 프로젝트들이다. 실험 데이타들에 대한 산점도를 그려 개발노력과 FP의 적합한 관계로부터 단순회귀분석 모델을 유도하였다. 또한, 다양한 소프트웨어 개발환경과 개발방법 등을 고려해 개발된 최근의 대용량 프로젝트에 대해 제안된 단순회귀분석 모델이 기존의 회귀분석 모델들보다 개발노력 추정 정확성이 월등히 좋음을 보였다.