• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.385-392
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• 2002

This paper introduces a new approach to analysis of error convergence for a class of iterative teaming control systems. Firstly, a nonlinear plant is represented using a Takagi-Sugeno(T-S) fuzzy model. Then each iterative learning controller is designed for each linear plant in the T-S fuzzy model. From the view point of two-dimensional(2-D) system theory, we transform the proposed learning systems to a 2-D error equation, which is also established if the form of T-S fuzzy model. We analyze the error convergence in the sense of induced L$_2$-norm, where the effects of disturbances and initial conditions on 2-D error are considered. The iterative teaming controller design problem to guarantee the error convergence can be reduced to the linear matrix inequality problem. This method provides a systematic design procedure for iterative teaming controller. A simulation example is given to illustrate the validity of the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1210-1215
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• 2000

Investigation is performed on the stability of general form of dynamic system under colored noise random disturbance whose damping and stiffness are varying in irregular manner along time, which is a preliminary result in the course of research on the characteristic and the control of the stochastic system. Adopted physical model is airfoil under random atmospheric disturbance, which becomes a "time-varying system" whose the governing equation is derived via F-P-K approach in stochastic sense. Control performance and effect of 'Heo-stochastic controller for colored noise' is studied. Also stochastic feature of flutter boundary is discussed as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.646-648
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• 2021

Sensors with wireless communication functions are essential for acquiring and transmitting spatio-temporal data that is not easily accessible in sensor network environments. However, these sensors lack adaptability to large amounts of sensing data processing or dynamic environments, resulting in over-consumption of power and network overhead. This paper proposes a mobile agent that can acquire, transmit, and process only the necessary data by applying thresholds, and presents methods for autonomous migration and communication processing of mobile agents.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.79-86
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• 2001

The six-components force measurements systems for rocket motors are used to measure multi components force generated by TVC(Thrust Vector Control) motors. This paper suggested the modeling scheme which is used in preliminary design and test analysis procedure and which can be applied to the existing other test stand in operation. The model whose parameters are determined by least square method makes the design engineer build the test stand to satisfy all kinds of requirements such as accuracy, operating condition and structural stability without tradeoff among the requirements. The experimental results shows that the proposed model has better accurate performances than those of other existing model.

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.125-134
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• 2009

A biological data acquisition based on web has emerged as a powerful tool for allowing scientists to interactively view entries form different databases, and to navigate from one database to another molecular-biology database links. In this paper, the biological conceptual model is constructed hybrid biological data model to represent interesting entities in the data sources to applying navigation rule property for each biological data source based on four biological data integrating layers to control biological data. When some user's requests for application service are occurred, we can get the data from database and data source via web service. In this paper, we propose a query processing model and execution structure based on integrating data layers that can search information on biological data sources.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.10-14
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• 2008

Computer-animated crowd scenes are often observed in computer games and feature films. The common way to model locomotion of large human crowds is to employ agent based methods where the behavior of each person is independently modeled. But for large crowds, it is difficult for a user to control all the individuals using individual behavior model. Instead, crowd behaviors can be controlled more intuitively at the group level than at the individual level. In this paper, we present the group force field model to simulate path following behavior for groups. A group is a set of characters who have the same goals, i.e. the same path to follow. We also define three characteristics of grouping behavior: alignment, cohesion, and distribution. Our group force field model preserves these characteristics while avoiding collisions. By using our model, user can generate desired group behaviors from line-up behavior to lumped one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.723-729
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• 2001

We are able to work on the shared virtual space in Web-based Collaborative Design System using only Internet and Web browser. The users connect to the Solid Modeler Server through m and they create 3D shape and manipulate them variously. Then the users will share 3D objects and two problems can arise. The users must be able to pick the objects effectively which they want to manipulate. When one of the users manipulates a particular object, others should not disturb with the same object. In this paper, picking is implemented not only by computing intersection of mouse pointer with the objects of the virtual world, but also by using capabilities and attributes of scene graph node, by setting bounds intersection testing instead of geometric intersection testing, by limiting the scope of the pick testing, using Java 3D. These methods can reduce the computation of picking and can pick 3D objects effectively and easily using the system of hierarchy. To have effective concurrency, we used shared lock and exclusive lock as the action in work space.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.4
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• pp.51-60
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• 2011

Authentication model in the wireless environment has many security vulnerabilities. However, there is no adapting standard method in this field. Therefore, we propose a fuzzy logic based authentication model to enhance the security level in the authentication environment. We use fuzzy logic based classification to construct our model, and also additionally utilize improved AHP and case-based reasoning for an appropriate decision making. We compute the context information by using the improved AHP method, use the proposed model to compute the security level for the input data, and securely apply the proposed model to the wireless environment which has diverse context information. We look forward to better security model including cloud computing by extending the proposed method in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.26-34
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• 2014

This study focuses on development of a risk level evaluation model for the intersection dilemma zone based on vehicle speed distribution approaching the intersection. The study results show that dilemma zone exists for all approaches selected for the study because the values of amber time have not been properly set, and that re-optimized values significantly reduce the dilemma zone risk level. It is also found that when normal distribution is assumed for vehicle approach speed the risk values similar to those for actual speed distributions can be obtained. When the risk level is found to be high, the amber time must be adjusted to reduce the length of the dilemma zone, or speed calming measures must be introduced so that vehicle speed be maintained under the speed value used when determining the amber time.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.49-58
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• 2009

Top-down approach in the intelligent robot research has focused on the single object intelligence however, it has two weaknesses. One is that has a high cost and a long spending time of sensing, calculating and communications. The other is the difficulty of responding to react changes in the unpredictable environment. we propose the collective intelligence algorithm based on Bottom-up approach for improving these weaknesses and the applied agent model and verify by simulation. The Modified Flocking Algorithm proposed in this research is the algorithm which is modified version of the concept of the Flocking (Craig Reynolds) which is used to model the flocks, herds, and schools in the graphics or games, and simplified the operation of conventional Flocking algorithm to make it easy to apply for the number of group robots. We modeled the Boid agent and verified possibility collectivization of the Modified Flocking Algorithm by simulation. And We validated by the actual multiple mobile robot experiment.