• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1318-1320
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• 1998

We have investigated the electrical characteristics of a MOSFET-structured silicon field emitter by employing Maxwell 2D and Silvaco simulators. The potential distribution is obtained by Maxwell 2D simulator and the field emission current is calculated by Fowler-Nordheim equations. The characteristics of MOSFET is simulated by Silvaco simulator. Simulated results are almost identical to the experimental results. Also, we have studied the emission characteristics as funtions of several geometric parameters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.9-15
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• 2016

Distribution networks are operated in radial fashion during the normal state. Loop configuration is also required temporally in case of live load transfer among the adjacent feeders. Voltage angles of each substation buses are very important data in order to calculate power flow of the loop structured distribution feeders. This paper proposes substation bus voltage angle calculation method using voltage angle difference measured at the normally open tie switches. Simulation case studies using Matlab simulink have been performed to establish feasibility of proposed method.

• The Journal of Information Technology
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• v.2 no.2
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• pp.269-279
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• 1999

SGML(Standard Generalized Markup Language) is proper to view, modify and create new electronic document as documentation standard to create and interchange the structured document information. Accordingly, a study on efficient storage and management of very large structured SGML document information is need. This paper proposes design of data modeling based on GROVE(Graph Representation Of property ValuEs) defined in HyTime(Hypermedia Time-based Structuring Language) and describes design of SGML document storage management system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.1
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• pp.20-25
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• 2002

This paper presents a genetic programming based evolutionary strategy for on-line adaptive learnable evolvable hardware. Genetic programming can be useful control method for evolvable hardware for its unique tree structured chromosome. However it is difficult to represent tree structured chromosome on hardware, and it is difficult to use crossover operator on hardware. Therefore, genetic programming is not so popular as genetic algorithms in evolvable hardware community in spite of its possible strength. We propose a chromosome representation methods and a hardware implementation method that can be helpful to this situation. Our method uses context switchable identical block structure to implement genetic tree on evolvable hardware. We composed an evolutionary strategy for evolvable hardware by combining proposed method with other's striking research results. Proposed method is applied to the autonomous mobile robots cooperation problem to verify its usefulness.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.3
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• pp.25-36
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• 1996

Conventional radial-basis-function networks and fuzzy systems have serious problems in dealing with the non1inea:r approximations on high-dimensional spaces due to the explosive increase of the number of hidden nodes or fuzzy IF-THEN rules. In order to avoid such problems, this paper proposes a tree-structured intelligent system in which semi-local basis functions form its basic elements, and develops a training algorithm for the proposed system based on the modified genetic algorithm and LMS rule. Theoretical analysis is performed on the approximation capability of the proposed system, together with experimental studies which demonstrate the effectiveness of the developed methodology.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.50.1-50
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• 2001

Dynamic optimization with partially structured model in a slurry-phase HDPE reactor is implemented by the modified hierarchical dynamic optimization. Optimal trajectories of MI and density of HDPE are calculated as controlled variables and optimal profiles of the concentrations of ethylene, hydrogen and comonomer are calculated as manipulated variables in dynamic optimization. MI, density, the concentrations of ethylene, hydrogen and comonomer are used as controlled variables and flow rates of ethylene, hydrogen and comonomer are sued as manipulated variables in control implementation. Two-level hierarchical method is applied in dynamic optimization to reduce computation time. In the upper level formulation ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.167.3-167
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• 2001

In this paper, a single degree-of freedom gimbal-structured micro gyroscope and signal processing part including capacitive sensing circuits and filters are designed, fabricated and experimented. We use capacitive sensing method with excitation signal, i.e. sensing excitation signal, to measure the displacement of the moving plate. So, Sensing Output Signal is modulated twice by the excitation signal and driving signal, which is profitable to decouple the driving and sensing mode, to reduce the effect of the acceleration, and to curtail the noises due to parasitic capacitance and driving signal. To reduce driving noises and to improve linearity, the excitation signals and driving signals are modified. Through frequency response analyses ...

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.431-441
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• 1991

A robust H$_{\infty}$ control design methodology and its application to a Space Station attitude and momentum control problem are presented. This new approach incorporates nonlinear multi-parameter variations in the state-space formulation of H$_{\infty}$ control theory. An application of this robust H$_{\infty}$ control synthesis technique to the Space Station control problem yields a remarkable result in stability robustness with respect to the moments-of-inertia variation of about 73% in one of the structured uncertainty directions. The performance and stability of this new robust H$_{\infty}$ controller for the Space Station are compared to those of other controllers designed using a standard linear-quadratic-regulator synthesis technique.que.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.652-657
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• 1991

Up to date, application areas of mobile robots have been expanded. In addition, Many types of LRF(Laser Range Finder) systems have been developed to acquire three dimensional information about unknown environments. However in real world, because of various noises (sunlight, fluorescent light), it is difficult to separate reflected laser light from these noise. To overcome the previous restriction, we have developed a new type vision system which enables a mobile robot to measure the distance to a object located 1-5 (m) ahead with an error than 2%. The separation and detection algorithm used in this system consists of pulse phase difference method and multi-stripe structured light. The effectiveness and feasibility of the proposed vision system are demonstrated by 3-D maps of detected objects and computation time analysis.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.183-186
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• 2003

A vision sensor should be calibrated prior to infer a Euclidian shape reconstruction. A point to point calibration. also referred to as a hard calibration, estimates calibration parameters by means of a set of 3D to 2D point pairs. We proposed a new method for determining a set of 3D to 2D pairs for the structured light hard calibration. It is simply determined based on epipolar geometry between camera image plane and projector plane, and a projector calibrating grid pattern. The projector calibration is divided two stages; world 3D data acquisition Stage and corresponding 2D data acquisition stage. After 3D data points are derived using cross ratio, corresponding 2D point in the projector plane can be determined by the fundamental matrix and horizontal grid ID of a projector calibrating pattern. Euclidian reconstruction can be achieved by linear triangulation. and experimental results from simulation are presented.