• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.140-148
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• 2010

The Taihu Basin is located in the east coast of China, where the threats of frequent floods have induced construction of massive, complex, hierarchical flood defense systems over the interconnected river networks. Digital modeling of flooding processes and quantitative damage assessment still remain challenging due to such complexity. The current research uses an integrated approach to meet this challenge by combining multiple types of models within a GIS platform. A new algorithm is introduced to simulate the impacts of the flood defense systems, especially the large number of polders, on floods distributions and damages.

• Proceedings of the ESK Conference
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• 1992.10a
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• pp.90-95
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• 1992

In this study, the application of fuzzy hierarchical analysis for modeling the inspection tasks with respect to the the improtances of the cognitive factors is considered and it's validity in cognitive researches is confirmed. The results of the relative importance of various cognitive factors can be served as a selection criteria for efficient inspection performance and the information of skilled learning for a inspection training program.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.1014-1022
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• 2002

An objective of Automated Highway Systems (AHS) is to increase the safety and throughput of the existing highway infrastructure by introducing traffic automation. AHS is an example of a large scale, multiagent complex dynamical system and is ideally suited for a hierarchical hybrid controller. We discuss a design issue of efficient hybrid controllers for the platoon maneuvers on AHS. For the modeling of a hybrid system including the merge and split operations, a safety distance policy is introduced for the merge and split operations. After that, the platoon system will be modeled by a hybrid system In addition, a hybrid controller for the proposed merge and split operation models is presented. Finally, the performance of the proposed hybrid control scheme is demonstrated via scenarios for platoon maneuvers.

• 시스템엔지니어링워크숍
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• s.4
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• pp.151-154
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• 2004

This paper presents the general system theory and its applications to the safety analysis method that is a recent trend over the traditional event-driven model. This new model is known as STAMP(Systems Theory Accident Modeling and Process)proposed by Nancy G. Leveson in MIT. The new model has benefits of systemic approaches concerning the system safety as a whole including the context it is in, its stimulants and outcomes, and its parts as well as the relationships among them in a holistic manner. The method consists of a hierarchical control structure, a process model, and the safety constraints governing the control. This paper demonstrates an example the contrasts the differences between the approaches of STAMP and the traditional safety models.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.88-95
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• 2003

A firm's business composition and the sales volume of each business segment are subject to change depending, to a considerable extent, on the firm's business strategy. These changes were weighted and represented as a single index, referred to by scholars in strategic management and industrial organization research fields as 'firm entropy' then its impact on firms' profitability was assessed over twelve years. The performance differences between contractor and non-contractor firms, as well as focused and diversified firms, were compared through a Longitudinal Data Analysis Technique within a Hierarchical Linear Modeling framework. Hypothesis was formulated based on firm diversification theories and previous research findings. The hypothesis was tested according to the modeling outcomes, and implications are presented. The research findings indicate that the level of firms' long-term profitability supports the argument that the construction industry is highly competitive and mature.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.450-454
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• 1988

In order to represent and analyze distributed system design, the model based on an extended form of Petri nets, which enables one to represent both the structure and the behavior of a distributed system, is predented. Behavioral properties of the design representation are verified by translating the extended Petri net into an equivalent ordinary Petri net. The model emphasizes the unified representation of control flows, hierarchical structure, and distributed system state. Modeling technique isemployed for the performance and function analysis of flexible manufacturing system with a set of processors.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.5
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• pp.461-468
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• 1997

A real-time collision-free trajectory control method for dual arm robot system is proposed. The proposed method is composed of two stages; one is to calculate the minimum distance between two robot arms and the other is to control the trajectories of the robots to ensure collision-free motions. The calculation of minimum distance between two robots is, also, composed of two steps. To reduce the calculation time, we, first, apply a simple modeling technique to the robots arms and determine the interested part of the robot arms. Next, we apply more precise modeling techniques for the part to calculate the minimum distance. Simulation results show that the whole algorithm runs within 0.05 second using Pentium 100MHz PC.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.3
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• pp.31-40
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• 1993

This paper deals with the modeling and scheduling for FMC(Flexible Manufacturing Cells). The FMC system composed of unit or multi cells is capable of improving productivity with flexibility for machine. However, the properties of multiple jobs and various alternatives results in tne dynamic states which make system management very complex. The extended Peti nets are used to represent for complex properties of FMC which performs short-term scheduling and dynamic operational scheduling. The hierarchical control structure and integlligent scheduling through expert module are adopted for efficiency of FMC operations. The computer simulation reveals that intelligent scheduling method is better than heuristics in various performance indices.

• Composites Research
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• v.15 no.5
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• pp.44-52
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• 2002

To study numerically the mechanical behaviors of advanced composite materials considering the microscopic phenomena as well as the macroscopic properties and behaviors, a multi-scale modeling and analysis by the mathematical homogenization method with the help of the finite element method(FEM) are reviewed. The hierarchical modeling strategy and the formulation are briefly described first to give some idea of the multi-scale framework. The latter half of this article focuses on the verification of the multi-scale analysis by the homogenization method in its applications to real advanced materials. The first example is the verification of the predicted macroscopic(homogenized) properties based on the microstructure of porous ceramics. In spite of the complexity of the random microstructure, the error between the predicted and the measured values was only 1%. Next, two applications to the process simulation of fiber reinforced polymer matrix composites are presented. The permeability characteristics are evaluated for sheared weave fabrics for resin transfer molding(RTM) simulation, and the thermoforming of FRTP sheet is analyzed considering the large deformation of the knit structure during the deep-draw forming was verified by comparison with the experimental results.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1081-1083
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• 2007

The study in river basin has been performed for the identify water quality impaired stream segments, to create a priority ranking of those segments, and to calculate the heavy metal ion distribution for each impaired segment based on chemical and physical water quality standards. Two methods for modeling the potential area-specific heavy metal distribution are pursued in this study. First, a novel approach focuses on distance. Heavy metal distribution can be associated with a particular small geographic area. Based on the derived estimates an distribution map can be generated. Second, the approach is used the near watershed by means of kriging interpolation algorithm. These approaches provide an alternative distribution mapping of the area. The exposure estimates from both of these modeling methods are then compared with other environmental monitoring data. A GIS-based model will be used to mimic the hierarchical stream structure and processes found in natural watershed. Specifically, the relationship between landscape variables and reach scale habitat conditions most influential found in the Abandoned mine will be explored.