• Journal of the Korea Safety Management & Science
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• v.5 no.3
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• pp.133-143
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• 2003

Even in the present situation where any general criterion on CRM dose not exist, utilization of CRM is expected to be actively continued, which will cause many problems. In this regard, evaluating CRM counts. As the result, projects are being suspended and budgets cut, plans for introducing CRM suspended or cancelled and many CRM software vendors and technical consulting firms are facing serious management crisis. Yet, this phenomenon can be regarded as an interim one. In fact, some cases that successfully introduced CRM show that CRM is migrating from small scale which is typical when introduced to larger scale through various tests. Therefore, this study tries to segment customer for the sloving the problem. And it make efficient customer management. Using this model, SN ratio of taguchi method for each of subjective factors as well as values of weights are used in this comprehensive method for customer. A example is presented to illustrate the model and to show a rank reversal when compared to a model that does not eliminate extreme values and eliminates the highest and lowest experts' values allocating the weights and the subjective factors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.4
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• pp.258-265
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• 2003

This paper suggests the noise reduction method of the engine cooling fan. The fan noise contribution to the OASPL of engine room was estimated and the noise source was identified for the rotating fan by sound intensity method. And the program for Predicting the noise spectrum of axial flow fan was also developed. The radiated acoustic pressure is expressed in terms of discrete frequency noise Peaks at BPF and its harmonics and the line spectrum at the broad band by the proposed noise generation mechanisms. In this Paper, it Is shown that the comparison of the measured and calculated noise spectra of fan validates the noise predicting program. And this paper presents the characteristics of the fan noise in order to modify the design parameters. Accordingly, the design parameters were determined for the noise reduction of the fan.

• Composites Research
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• v.25 no.6
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• pp.230-235
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• 2012

This paper presents the vibration characteristics and the optimization using the orthogonal array about applied composite optical structure of an aircraft. To acquire the vibration characteristics for stable line of sight, modal analysis are performed by using multi-body program ADAMS. And to optimize optical structure, for design variables were selected, larger-the-better characteristics were considered using results of S/N ratio and orthogonal array $L_9(3^4)$. When bearing constraints are selected, radial, axial and moment stiffness value are used to analysis for optimization until now. But B.S.R which is non-dimensional parameter is proposed, structures including bearings can be used for optimization. And then having a result of lager-the-better, the optimized values of each design variable were successfully suggested.

• Journal of the Korea Safety Management & Science
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• v.4 no.4
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• pp.109-118
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• 2002

Such effects would be paid off in the right way only when management of the firms perform marketing activities focusing on long term effectiveness, which would drive company profits up and keep them for long. Demands of customers are being changed and varied. In this result with the advantage of mass marketing and database marketing have been drawing attentions from company. To fulfill these demands of customer, they need a concept of eCRM(Web based Customer Relationship Management), and go from selling products and services, or gathering customer requests, up to the phase of solving customer's problem by real time or previous action. With the help of internet, the frequency and speed of the problem solving has improved greatly. For these purposes, we try to determine the most important and most urgent factors in eCRM: utilization by using SN Ratio Decision making, one of the Multi-criteria decision-making methods SN Ratio Decision making is widely used for determining relative magnitude per evaluation item, i. e. priority on problems and is expected to make more systematic and objective evaluations than conventional methods do. Even in the present situation where any general criterion on eCRM dose not exist, utilization of eCRM is expected to be actively continued, which will cause many problems. In this regard, evaluating eCRM counts.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.31-39
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• 2021

In this paper, warpage analysis that separates PCB for PoP (Package on Package) into unit and substrate using FEM (Finite Element Method), analysis of the effect of layer thickness on warpage, and SN (Signal-to-Noise) ratio by Taguchi method was carried. According to the analysis result, the contribution of the circuit layer on warpage was very high in the unit PCB, and the contribution of the outer layer was particularly high. On the other hand, the substrate PCB had a high influence of the circuit layer on warpage, but it was relatively low compared to the unit PCB, and the influence of the solder resist was rather increased. Therefore, considering the unit PCB and the substrate PCB at the same time, it is desirable to design the PCB for PoP layer-by-layer structure so that the outer and inner circuit layers are thick, the top solder resist is thin, and the thickness of the bottom solder resist is between 5 ㎛ and 25 ㎛.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.243-250
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• 2009

The expression of signal to noise ratio (SNR) is derived for the individual echo sounder and for the general specifications of commercial echo sounder. The SNR is depicted by several factors on transmitting and receiving, sound propagation, scattering by fishes, and mainly self ship noise. The detection ranges of echo sounders in depth and breadth are derived by finding the border of an acceptable SNR. The detection ranges are computed for the echo sounders of individual and general specifications. Generally, the detection range is lager for low frequencies. Increasing an electrical power and a diameter of transducer is not as effective for high frequencies as for low frequencies to increase the detection range. The theoretical results of the detection range can be applied to design low electrical power echo sounder for coastal use, to select an appropriate echo sounder, to know the capability of a sounder, and to interpret echograms. A method for evaluating and designing low electrical power echo sounder is developed. A universal diagram for the basic design of the low electrical power echo sounder where SNR is plotted against frequency is developed. An appropriate frequency, transducer diameter, and beam width are easily determined by using the diagram.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.127-133
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• 2012

To achieve low-cost and high-efficiency of thin-film solar cells applications, the sol-gel method that can be coated on a large area substrate, obtain homogeneous thin films of high purity was used. We studied structural and optical characteristics versus annealing temperature of $Cu_2ZnSnS_4$ which has kesterite structure by substitution low-cost sulfur (S) instead of high-cost selenium (Se). By analyzing XRD patterns, main peak was observed at $2{\theta}=28.5^{\circ}$ when Zn/Sn ratio is 0.8/1.2. And when we observed kesterite structure which has orientation of (112) direction, the more annealing temperature increase the bigger strength of (112) direction is. $Cu_2ZnSnS_4$ thin film showed characteristics of kesterite structure at $550^{\circ}C$. And when we calculated lattice constant, a = 5.5047 and $c=11.014{\AA}$ as same JCPDS (Joint Committee on Powder Standards) data measured. We measured optical transmittance to analyze optical characteristics. Optical transmittance was lower than 65 % at visible ray (${\lambda}=380{\sim}770nm$).