• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.137-140
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• 2000

In this paper, we have proposed an efficient test generation method for asynchronous circuits. The test generation is based on specification level, especially on Signal Transition Graph(STG)〔1〕 which is a kind of specification method for asynchronous circuits. To conduct a high-level test generation, we have defined a high-level fault model, called single State Transition Fault(STF) model on STG and proposed a test generation algorithm for STF model. The effectiveness of the proposed fault model and its test generation algorithm is shown by experimental results on a set of benchmarks given in the form of STG. Experimental results show that the generated test for the proposed fault model achieves high fault coverage over single input stuck-at fault model with low cost. We have also proposed extended STF model with additional gate-level information to achieve higher fault coverage in cost of longer execution time.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권1호
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• pp.29-36
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• 1998

An instantaneous unit sediment graph (IUSG) model is investigated for prediction of sediment yield from an upland watershed in Northwestern Mississippi. Sediment yields are predicted by convolving source runoff with an IUSG. The IUSG is the distribution of sediment from an instantaneous burst of rainfall producing one unit of runoff. The IUSG, defined as a product of the sediment concentration distribution (SCD) and the instantaneous unit hydrograph (IUH), is known to depend on the characteristics of the effective rainfall. The IUH is derived by the Nash model for each event. The SCD is assumed to be an exponential function for each event and its parameters were correlated with the effective rainfall characteristics. A sediment routing function, based on travel time and sediment particle size, is used to predict the SCD.

• 대한산업공학회지
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• 제23권2호
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• pp.323-341
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• 1997

Traditionally, the Process Planning problems and the Scheduling problems have been considered as independent ones. However, we can take much advantages by solving the two problems simultaneously. In this paper, we deal with the enlarged problem that takes into account both the process planning and the scheduling problems. And we present a solution algorithm for the problem assuming that the given process plan data is represented by AND/OR graph. A mathematical model(mixed ILP model) whose objective is the minimization of the makespan, is formulated. We found that we can get the optimal solutions of the small-size problems within reasonable time limits, but not the large-size problems. So we devised an algorithm based on the decomposition strategy to solve the large-scale problems (realistic problems) within practical time limits.

• 한국환경과학회지
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• 제2권1호
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• pp.29-36
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• 1993

An instantaneous unit sediment graph (IUSG) model is investigated for prediction of sediment yield from an upland watershed In Northwestern Mississippi. Sediment yields are predicted by convolving source runoff with an IUSG. The IUSG is the distribution of sediment from an instantaneous burst of rainfall producing one unit of runoff. The IUSG, defined as a product of the sediment concentration distribution (SCD) and the instantaneous unit hydrograph (IUH), is known to depend on the characteristics of the effective rainfall. The IUH is derived by the Nash model for each event. The SCD is assumed to be an exponential function for each event and its parameters were correlated with the effective rainfall characteristics. A sediment routing function, based on travel time and sediment particle size, is used to predict the SCD.

• Industrial Engineering and Management Systems
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• 제15권4호
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• pp.374-384
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• 2016

The efficiency of a supply chain can be extremely affected by its design which includes determining the flow pattern of material from suppliers to costumers, selecting the suppliers, and defining the opened facilities in network. In this paper, a multi-objective multi-echelon multi-product supply chain design model is proposed in which several suppliers, several manufacturers, several distribution centers as different stages of supply chain cooperate with each other to satisfy various costumers' demands. The multi-objectives of this model which considered simultaneously are 1-minimize the total cost of supply chain including production cost, transportation cost, shortage cost, and costs of opening a facility, 2-minimize the transportation time from suppliers to costumers, and 3-maximize the service level of the system by minimizing the maximum level of shortages. To configure this model a graph theoretic approach is used by considering channels among each two facilities as links and each facility as the nodes in this configuration. Based on complexity of the proposed model a multi-objective Pareto-based vibration damping optimization (VDO) algorithm is applied to solve the model and finally non-dominated sorting genetic algorithm (NSGA-II) is also applied to evaluate the performance of MOVDO. The results indicated the effectiveness of the proposed MOVDO to solve the model.

• 한국음향학회지
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• 제15권1호
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• pp.54-60
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• 1996

패턴인식이나 영상이해의 영역에서는 같은 물체라도 잡음이나 왜곡에 의하여 모양이 훼손되어 다른 물체로 인식될 수 있다. 따라서 물체 인식에서는 두 물체가 완전히 동일한지 여부를 판정하는 것보다는 두 물체가 서로 어느 정도 유사한가를 판정하는 것이 중요한 경우가 많다. 이 논문에서는 훼손된 기호의 인식을 위하여 기호를 표현하는 두 그래프 표현간의 유사도 측정을 이용한 기호 인식 방법을 제안하였다. 제안한 기호 인식 방법은 런 그래프(run graph)를 이용하여 인식 대상 기호를 노드(node)와 에지(edge)로 구성되는 그래프 형태로 표현하고 임베딩 변환(embedding transform)을 포함한 생성 규칙을 사용하여 입력 그래프를 참조 모델 그래프와 유사한 형태로 변형시킨다. 이러한 과정에서 변형된 최종 그래프와 모델 그래프간의 구조적 유사성과 변형시 사용된 생성 규칙의 수를 이용하여 그래프간 유사도를 측정함으로써 기호를 인식하였으며 이의 응용 분야로서 악보에서 비음표 기호 인식에 사용하였다. 이 결과 96%의 인식률을 얻었으며 기호가 심하게 훼손되지 않은 경우에는 거의 인식에 성공하였다.

• 로봇학회논문지
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• 제9권1호
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• pp.1-10
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• 2014

In recent years, the research of 3D mapping technique in urban environments obtained by mobile robots equipped with multiple sensors for recognizing the robot's surroundings is being studied actively. However, the map generated by simple integration of multiple sensors data only gives spatial information to robots. To get a semantic knowledge to help an autonomous mobile robot from the map, the robot has to convert low-level map representations to higher-level ones containing semantic knowledge of a scene. Given a 3D point cloud of an urban scene, this research proposes a method to recognize the objects effectively using 3D graph model for autonomous mobile robots. The proposed method is decomposed into three steps: sequential range data acquisition, normal vector estimation and incremental graph-based segmentation. This method guarantees the both real-time performance and accuracy of recognizing the objects in real urban environments. Also, it can provide plentiful data for classifying the objects. To evaluate a performance of proposed method, computation time and recognition rate of objects are analyzed. Experimental results show that the proposed method has efficiently in understanding the semantic knowledge of an urban environment.

• 한국콘텐츠학회논문지
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• 제22권8호
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• pp.33-43
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• 2022

지식 그래프 및 단백질 상호 작용과 같은 실제 데이터에서 개체들과 개체들의 관계 및 구조를 나타내기 위해 레이블 그래프를 사용한다. IT의 급속한 발전과 데이터의 폭발적인 증가로 사용자에게 관심 있는 정보를 제공하기 위한 서브 그래프 매칭 기술이 필요하다. 본 논문은 레이블의 의미적 유사성과 그래프 구조 차이를 고려한 근사 Top-k 서브 그래프 매칭 기법을 제안한다. 제안하는 기법은 레이블 의미적 유사도를 고려하기 위하여 FastText을 활용한 학습 모델을 이용한다. 레이블 간 의미적 유사도를 미리 계산한 LSG(Label Similarity Graph)를 통해 처리 속도의 효율을 높인다. LSG를 통해 레이블이 정확하게 일치해야 확장이 가능한 기존 연구의 한계를 해결한다. 2-hop까지 탐색을 수행함으로써 질의 그래프에 대한 구조적 유사성을 지원한다. 매칭된 서브 그래프는 유사도 값 기반으로 Top-k 결과를 제공한다. 제안하는 기법의 우수성을 보이기 위하여 다양한 성능평가를 수행한다.

• 한국CDE학회논문집
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• 제3권3호
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• pp.145-153
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• 1998

An approach has been developed to generate parametric models with Boolean operations. The approach combines Boolean operations and graph manipulation on the constraints imposed on primitives. A Boolean operation is first performed on two primitives and new geometric elements such as vertices and edges are computed. Then to generate the constraint graph of the polygon the each constraints graph of two primitives are merged by adding the new geometric elements with its corresponding constraints. In the merging process, some of the geometric elements belonging to the primitives may be eliminated based on its contribution to the polygon. A computer implementation in a 2D space is described to illustrate the approach with examples.

• Industrial Engineering and Management Systems
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• 제2권1호
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• pp.35-44
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• 2003

Recovery of end-of-life (EOL) products is an environmentally and economically sound way to achieve many of the goals of sustainable development. Many product recovery systems are dependent upon destructive disassembly such as shredding, which undesirably causes a large volume of shredder dust and makes parts reuse impossible. Although non-destructive disassembly has been considered as an alternative for solving the problems, the classification of disassembled items has not been sufficiently investigated. In this paper, we propose a model that mathematically optimizes the disassembly and classification of EOL products. Based on the AND/OR graph that illustrates all possible disassembly sequences of a given product, we identify the physical properties that are considered as constraints in the model. As a result of the solution procedure, the recovery problem can be transformed into a mixed integer linear programming (MILP) model. We show an example that illustrates the concept of our model.