• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.106-109
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• 2000

There have been proposed two types of low bit rate vocoder upto now : One is MBE type using the spectrum modeling and another is CELP type using the hybrid coding method. CELP type vocoder has mainly studied between them. Specially, much of intensity is concentrated in CELP vocoder due to the emergence of Internet Phone and PCS in a domestic. In order to improve the speech quality in CELP vocoder, in this paper, we proposed a new spectrum analysis algorithm with variable window, In CELP vocoder, the spectrum of the synthesised speech signal is distorted because the fixed size windows is used for spectrum analysis. So we have measured the spectral leakage and in order to minimize the spectral leakage have adjusted the window size. Applying this method G.723.1 ACELP, we can get SD(Spectral Distortion) reduction 0.084(dB), residual energy reduction 6.3% and MOS(Mean Opinion Score) improvement 0.1.

• Journal of Korean Society for Quality Management
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• v.17 no.2
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• pp.142-148
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• 1989

In order to determine the level of service which minimizes the total of expected cost of service and the expected cost of waiting for that service, the important considerations are to evaluate the distance traveled to and from a service facility (D) and the expected number of mechanics in queueing system (L). The travel-time models are very useful when the servers must travel to the customer from the service facility. Thus, in this paper we studied on the determination of the optimal service level by the travel-time models. In order to decide the optimal service level, (D) has been introduced as a uniform distribution and (L) has been introduced as M/M/S model of queueing theory.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.215-223
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• 1993

A paired comparison which is a method of comparative judgements is widely used to increase the amount of information transmitted to human sense organ. In this study, a paired comparison method is proposed for the discrimination capacity and preference analysis of non-skilled sensory inspectors. We consider on order effect, that is, difference of evaluation occurred as a result of sample presentation by random order. The purpose of this paper is to determine a sample with the highest preference degrees by analyzing a discrimination capacity and evaluating preference degrees of sensory inspectors. An analysis of a discrimination capacity is bared on the capacity index obtained by an eigen-vector method and an evaluation of preference degrees is performed by a significance test.

• Journal of Korean Society for Quality Management
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• v.38 no.1
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• pp.42-51
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• 2010

For the fractional factorial designs, the resolution-IV designs can be used when we want to estimate the main effects and to investigate the structure of the non-negligible two-factor interaction effects, when the three-factor and higher order interaction effects are all negligible. However we need to add the additional treatment combinations in order to identify the influential interactions for the resolution-IV fractional factorial designs. In this paper we investigate the statistical structure for 3-level resolution-IV designs constructed by fold-over scheme and introduce a method for analyzing the influential two-factor interactions.

• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.267-274
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• 2008

This paper reports generating creative ideas based on customer needs using Kano Model and Importance-Differentiation Matrix (I-D Matrix). Nowadays, every customer demands creative ideas on product innovations in order to be satisfied her needs. However, most existing methods are limited to get creative ideas that reflect customer needs. Any creative ideas that do not fully reflect customer needs are obviously more difficult to succeed in the market than those that reflect customer needs. This paper distinguishes each quality elements the customer needs in terms of Kano Model. And it presents the effective ways of generating creative ideas by I-D Matrix in order to overcome current uppermost limits.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.129-138
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• 2010

For the fractional factorial designs, the resolution-IV designs can be used when we want to estimate the main effects and to investigate the structure of the non-negligible two-factor interaction effects, when the three-factor and higher order interaction effects are all negligible. However we need to add the additional treatment combination in order to identify the influential interactions for the resolution-IV fracrtional factorial designs. In this paper we investigate the statistical structure for 3-level resolution-IV designs constructed by fold-over scheme and introduce a method for analyzing the influential two-factor interactions.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.157-160
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• 2010

Almost all companies have paid much attention to the safety management ranging from maintenance to operation even at the stage of designing in order to prevent accidents, but fatal accidents continue to increase throughout the world. In particular, it is essential to systematically prevent such fatal accidents sa fire, explosion or leakage of toxic gas at factories in order to not only protect economic losses and environmental pollution. In addition, HRA may be used to detect the human errors which may cause accidents or trace back to any mistake on the part of workers. This work focuses on the coincidence of human error and mechanical failure for management of human error, and on some important performance shaping factors to propose a method for improving safety effectively of the process industries.

• Journal of Korean Society for Quality Management
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• v.22 no.4
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• pp.40-58
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• 1994

Some systems such as early warning system should be inspected occasionally in order to detect failures. If the system is inspected too frequently, inspection cost increases. On the other hand, if the number of inspections is reduced too much, the undetected system downtime cost increases. Thus, it is of interest to find effective inspection schedule, which minimizes the sum of inspection and downtime costs. When the system has increasing failure rate, inspection intervals get shorter as time goes on. But a common practice is to inspect the system at predetermined periodic intervals. In this paper, periodic inspection policy and a modified periodic inspection policy are considered. The modified policy is easily applicable and cost-effective. Some numerical examples are included in order to explain the modified inspection ploicy and its cost performance.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.102-112
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• 1995

Estimation of each of mean response, difference between mean responses and derivatives of the response function is a possible objective of a response surface design. These objectives are to be achieved simultaneously when an experiment is designed to improve mean response. For the situations where departure from the assumed model is suspected, first and second order designs for improving mean response are obtained by combining minimum bias designs for the individual design objectives. D- and A-optimalities are used for selecting specific second order designs. The results are applied to central composite designs.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.11-14
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• 2012

The category for waterproofing is one of construction process most affected by falling-off in price competitiveness, construction quality, and material performance. Therefore, in order to select of waterproofing construction firms, it is necessary to consider Incorporating both price competitiveness and construction quality. In this article, I would like to analyze 10 Factors for Selecting using fuzzy-AHP model, including the survey of the waterproofing experts. This fuzzy-AHP model can be shown to calculate the fuzzy trigonometrical function to reflect weights for preference of 10 factors for the waterproofing construction firms. It was found from the result that waterproofing construction firms was searched order of priority for select by fuzzy-AHP model.