• Journal of Power System Engineering
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• v.9 no.2
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• pp.65-72
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• 2005

A new approach is presented to design a robust sampled-data controller for an experimental flexible beam carrying an unknown payload at its free end. The purpose of this paper is to move the free end of the beam to a desired position in the specified time under vibration suppression. We derive a transfer function nominal model for the beam and quantitative description of model uncertainties based on experimentally obtained frequency response data. Robust controllers are designed by applying the sampled-data $H_{\infty}$ control and ${\mu}m-theory$, in which two types of uncertainties, structured and unstructured uncertainties, are adopted for satisfactory performance in terms of hinge position regulation and vibration damping, besides obviously asymptotic stability. The effectiveness of the proposed method is confirmed through simulation and experimentation.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.138-145
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• 1998

Recently, TCS(Traction Control System) is attracting attention, because it maintains traction ability and steerability of vehicles on low-$\mu$ surface roads by controlling the slip rate between tire and road surface. The development of TCS control law is difficult due to the highly nonlinearity and uncertainty involved in TCS. A fuzzy logic approach is appealing for TCS. In this paper, fuzzy logic controller for TCS is introduced and evaluated by the computer simulation with 8 DOF vehicle model. The result indicate that the fuzzy logic TCS improves vehicle's stability and steerability.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.52-58
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• 2007

We propose a new contact detection algorithm for fine pitch wire bonding. Fast and stable contact detection of the z-axis in wire bonding is extremely important to maintain the quality of fine pitch gold wire bonding processes, which use a small pad less than $70{\mu}m$ in diameter. A small perturbation in the contact detection time causes a large difference in the size of the formed squashed ball. The new detection method is based on a statistical approach and designed for a discrete Kalman filter. It is faster and has smaller detection time variations than conventional detection methods. Experimental results are presented to demonstrate the advantages of the proposed algorithm.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.375-378
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• 2003

In the present study, a new approach to predict the strength of sintered materials has been carried out and a new framework combining neck growth model and ideal pore model has been established based on the results of tensile tests on powder injection molded specimens with the various porosity. Powder injection molding (PIM) uses the shaping advantage of injection molding but is applicable to metals and ceramics. PIM delivers structural materials in a shaping technology previously restricted to polymers. 17-4 PH stainless steel powders with average diameters of 10 $\mu\textrm{m}$ were injection-molded into flat tensile specimens sintered at the various temperatures ranging from 900 to 1350$^{\circ}C$ for 1h. The relationships between strength and porosity were applied to the experimental results and verified.

• Journal of the Korean earth science society
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• v.31 no.5
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• pp.465-474
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• 2010

Real-time rainfall monitoring is of great practical importance over the highly populated Indochina area, which is prone to natural disasters, in particular in association with rainfall. With the goal of d etermining near real-time half-hourlyrain estimates from satellite, the three-layer, artificial neural networks (ANN) approach was used to train the brightness temperatures at 6.7, 11, and $12-{\mu}m$ channels of the Japanese geostationary satellite MTSAT against passive microwavebased rain rates from Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and TRMM Precipitation Radar (PR) data for the June-September 2005 period. The developed model was applied to the MTSAT data for the June-September 2006 period. The results demonstrate that the developed algorithm is comparable to the PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks) results and can be used for flood monitoring across the Indochina area on a half-hourly time scale.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.102-106
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• 2002

Development of high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. The detail of the model proposed is described in the paper together with the experimental methodologies using a proposed compact measurement system to examine the validity of the proposed approach. The results showed the machining accuracy could be maintained to better than $\pm$ 5$\mu\textrm{m}$ while using this sensor.

• MALSORI
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• no.56
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• pp.195-206
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• 2005

Discrimination between speech and music is important in many multimedia applications. In this paper, focusing on the spectral change characteristics of speech and music, we propose a new method of speech/music discrimination based on cepstral distance. Instead of using cepstral distance between the frames with fixed interval, the minimum of cepstral distances among neighbor frames is employed to increase discriminability between fast changing music and speech. And, to prevent misclassification of speech segments including short pause into music, short pause segments are excluded from computing cepstral distance. The experimental results show that proposed method yields the error rate reduction of$68\%$, in comparison with the conventional approach using cepstral distance.

• MALSORI
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• no.49
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• pp.63-75
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• 2004

Most existing telephone speech transmitted in current public networks is band-limited to 0.3-3.4 kHz. Compared with wideband speech(0-8 kHz), the narrowband speech lacks low-band (0-0.3 kHz) and high-band(3.4-8 kHz) components of sound. As a result, the speech is characterized by the reduced intelligibility and a muffled quality, and degraded speaker identification. Bandwidth extension is a technique to provide wideband speech quality, which means reconstruction of low-band and high-band components without any additional transmitted information. Our new approach considers to exploit harmonic synthesis method for reconstruction of low-band speech over the CELP coded speech. A spectral distortion measurement and listening test are introduced to assess the proposed method, and the improvement of synthesized speech quality was verified.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.360-365
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• 2006

Most organizations adopt a process-based approach to manage their operations and now business process management(BPM) is a well-established concept. Because ISO 9001:2000 emphasizes process based, Korea Institute of Science and Technology Information has taken ISO 9001:2000 certificate in November 11, 2003 and now implements quality management systems based on BPMS further applies Hypertext. We call it Online KQMS (KISTI Quality Management System). And Online KQMS is implemented under a platform independent framework based on the web environment. Online KQMS based on BPMS and Hypertext is a new example in field of ISO quality management and is expected to support process management well.

• Archives of design research
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• v.6 no.1
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• pp.1-10
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• 1993

This paper described design as a purposeful human activity for solving its problems. This means, problem solving is finding a way to get from some initial situation to a desired goal.In order to do this, like a voyage, there should be a compass, and a route map to guide the designer through the design process. Evaluation gives information about the way a design is proceeding and suggests the direction in which change should be made in order that the complex of design concepts should be fulfilled in a satisfactory manner.I think Pugh's total design model discussing in this paper takes a layered approach through a series of sequential actions, part of which is to find the product status. Each layer has the $$\mu$ti-dimensional elements, Product Design Specification (PDS) around the design core. I made a comparative study of several evaluation tools wi th Pugh's model and examined the criteria for evaluation and the rating / weighing methods.It needs, however, more study in order that PDSs may have its values and be fixed from the dynamic design concepts.