• Journal of the military operations research society of Korea
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• v.9 no.1
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• pp.63-68
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• 1983

The ideal way of eliminating errors in a large scale software system is to test the software with all possible inputs, providing sufficiently large amount of execution time. However, in practice, the test must be performed within given budget and time limits. Therefore, to perform the test under given constraints, we have to properly select inputs and determine the execution time for each selected inputs. This paper studies the distribution of number of errors at a given time as well as the distribution of time required to reduce the number of errors to a certain level. We assumed that error occurrence times are distributed exponentially (not necessarily identical) and the number of errors at the initial stage is known or estimable.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.85-89
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• 1997

We used a three-dimensional motion capture method to measure the grasping reach of Korean. This method was applied well to the grasping reach measurement with low measurement error and high efficiency. We measured the grasping reach of 29 males and 21 females at the different height from seat reference level; -10, 0, 30, 60, and 90cm. The grasping reach data were summarized at each 15 .deg. in polar corrdinates to compare with the former researches. If the number of subjects increases in the supplement research, the grasping reach data will be used in the ergonomic design of the driver's cabin or workstations in industry.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.107-113
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• 1997

In this paper, an interfacing method to control rehabilitation assitance system with bio-signal is proposed. Controlling with EMG signals method has certain advantage on signal-collecting, but has some drawbacks in the function resolution of EMG signals because data-processing process is not efficient. To improve function-resolution and to increase the efficiency of EMG signal interfacing with rehabilitation assistance system, Multi-layer Perception which is highly effective with static signal and hidden-Markov model for dynamic signal resolving are fused together. In proposed method. The direction and average speed of the rehabilitation assitance system are controlled by the trajectory control and estimation of the moving direction result from the fused model. From the experiment, proposed GMM and 2-level MLP hybrid-classifier yielded 8.6% perception-error rate, improving function resolution. New acceleration control method constructed with 3 nested linear filter produced continuous acceleration paths without the information of destination point. Thus, the mass output caused by non- continuous acceleration-deceleration was eliminated. In the simulation, the necessary calculation, in the case of multiplication, was reduced by 11.54%.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.11
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• pp.1089-1093
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• 2008

This paper presents a robust state observer design for a class of Lipschitz nonlinear systems with time delay and external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level in spite of the existence of time delay. Finally, a numerical example is provided to verify the proposed design method.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.815-818
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• 1998

Hardware formal verification involves the use of analytical techniques to prove that the implementation of a system confroms to the specification. The specification could be a set of properties that the system must have or it could be an alternative representation of the system behavior. We can represent our behavioral specification to be written in VHDL coding. In this paper, we proposed a new hardware design verification method. For theis method, we assumed that a verification pattern already exists and try to make an algorithm to find a place where a design error occurred. This method uses an hierarchical approach by making control flow graph(CFG) hierarchically. From the simulation, this method was turned out to be very effective that all the assumed design errors could be detected.

• Korean Journal of Computational Design and Engineering
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• v.9 no.3
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• pp.246-252
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• 2004

Presented in this Paper is a Micro Machining Service .(MIMS) based on the World Wide Web technologies. In order to ensure easy access to the service, the web browsers are used as the user interface. The pan geometry as an STL file is uploaded with process parameter for 3-axis CNC milling. Depending on the predefined user level, novice or expert, the user interface requires different parameters for process planning. An STL-based CAM resides in the server and automatically provides NC codes upon user's request. Tool-paths for scanning and pencil-cut, which are interference-free and precise, are created by the curve-based polyhedral machining method. A couple of sample parts were fabricated by a micro endmill with 127 fm diameter. From the tests, the parts fabricated by scanning followed by pencil-cut resulted in less error(within 2%) than the parts machined only by scanning tool-path.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.243-248
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• 2001

A radial artery pulse wave is well known as a good mans to diagnose human body condition in th field of Chinese medical science. Information about constitution as well as organs can be obtained by detecting the artery pulse wave. Recently, the information about the human body constitution may be utilized in accelerating the recovery process of the patient on the basis of comprehensive diagnosis. A radial artery pulse wave is considered as one of promising means in examining the human body constitution. Since the examination has been conducted by the feeling of finger, the diagnosis may occasionally have uncertainty or fatal error. In this paper, a new measuring system is suggested and developed to examine the pattern of a pulse wave correctly. The system is composed of four pressure vessels, pressure sensors and air supplying pumps. One of them is utilized for appropriately pressing the radial artery, three of them for detecting pressure change in several mmHg level. The detected data is shown and discussed.

• Transactions of Materials Processing
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• v.22 no.2
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• pp.93-100
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• 2013

A tryout is a series of process optimization for robust stamping before transfer to the press shop. During tryout, the drawbead control, blank shape determination, binder surface modification, etc., are carried out mainly by a trial-and-error approach. As the level of difficulty of the stamping process increases, the formability becomes more sensitive to the contour of deformed shape, i.e. the blank shape. A digital tryout technique, which simulates a real tryout process, is proposed in this study for challenging stamping processes. Since digital tryout is carried out on a desktop, not in a press shop, a precise control of the deformed contour can be achieved if an optimal blank design technique is utilized. In this work, the proposed digital tryout technique is validated by successful applications to different automotive parts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1546-1552
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• 1993

We proposed an adaptive block truncation coding(BTC) using gradient and a new initial value. We used gradient of sobel operator as a new category classification coefficient to reduce Jagged appearance at edge part. We defined a new initial value to reduce large quantization error in the 4-level quantizer block including edge part. By computer simulations, we showed that the proposed method less computation load, reduced jagged appearance at edge part, also improved PSNR more than the conventional adaptive BTC.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.517-520
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• 2008

A voltage-programming pixel circuit, which compensates the threshold voltage shift of TFTs and the degradation of OLED, is proposed for large sized a-Si:H active matrix organic light emitting diode (AMOLED) applications. Considering threshold voltage variation (or shift), OLED degradation and reverse bias annealing, HSPICE simulation results indicate that luminance error of every gray level is less than 0.4 LSB under the condition of +1V threshold voltage shift and from -0.2 LSB to 2.6 LSB within 30% degradation of OLED in the case of 40-inch full HDTV condition.