• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.628-634
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• 2005

We have simulated and proposed novel optical cavity, which has two elliptical mirrors, for NDIR gas sensor module and have tested it from 0 ppm to 2,000 ppm $CO_2$ concentration. The proposed sensor module shows the maximum peak voltage at 500 ms pulse modulation time, however, it shows a maximum voltage changes at 200 ms pulse duration with 18,000 times amplification gain. From 0 ppm to 2,000 ppm, the voltage difference of sensor module $({\Delta}V)$ shows 360 mV at 200 ms pulse duration and 3 sec turn-off time. The response time of designed sensor module is about 30 seconds.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.209-212
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• 2002

본 논에서는 기존의 무효전력 보상을 정의하고 순시 유효전력 개념들을 도입한 제어 기법을 제안하였다. 이 기법은 배전 계통에서 비선형 부하로 인한 고조파 제거 기능에 보다 효과적임을 알 수 있다. PSCAD/EMTDC를 이용한 시뮬레이션을 통하여 전통적인 무효전력 보상 기법에 근거한 제어 기법보다 좋은 성능이 있음을 보였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.10
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• pp.870-875
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• 2002

Ba(Zn$_1$-xCox)TaO$_3$[BZCT] ceramics were Prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of 1450∼1550$\^{C}$ for 5 hr in air. The crystal structure of BZCT ceramics was investigated by the XRD. The microstructure of the specimens were observed by SEM. The structural properties of BZCT specimens were investigated as a function of composition and sintering temperature. All BZCT ceramics sintered over 1550$\^{C}$ were showed a polycrystalline complek perovskite structure without second phases and any unreacted materials. The density of BZCT (70/30) specimen sintered at 1550$\^{C}$ was 6.31g/㎤. In the case of the BZCT(70/30) ceramics sintered at 1550$\^{C}$ for 5 hours, dielectric constant, qualify factor and temperature coefficient of resonant frequency for microwave dielectrics application were a good value of 29, 16,468 at 10㎓ and -4.4 ppm/$\^{C}$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.53-56
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• 2004

This paper presents the improved burn-in method for the reliability of SRAM in MCP Semiconductor reliability is commonly improved through the burn-in process. Reliability problem is more significant in the Multi Chip Package, because of including over two devices in a package. In the SRAM-based Multi Chip Package, the failure of SRAM has a large effect on the yield and quality of the other chips - Flash Memory, DRAM, etc. So, the quality of SRAM must be guaranteed. To improve the quality of SRAM, we applied the improved wafer level burn-in process using multi cell selection method in addition to the current used methods. That method is effective in detecting special failure. Finally, with the composition of some kinds of methods, we could achieve the high qualify of SRAM in Multi Chip Package.

• Culinary science and hospitality research
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• v.8 no.1
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• pp.107-123
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• 2002

As result of analysis of the importance in this study majority the answerers indicated as recognize it important and indicated that shows difference in average among the groups. In the age there was difference among group by marketing quality and symbolic quality of menu was indicated and in the symbolic quality factor of menu as the younger age indicate much more important. There was no factor indicates do florence in average among groups subject to educational degree however, in the marketing quality and symbolic quality of the menu the higher academic degree regards it higher as indicated. As a result of difference analysis subject to channel of education it indicated as appearance of difference among the groups among factors of internal quality, marketing quality and symbolic quality of the menu. The average among groups subject to number of consecutive years indicated as there is difference by factors of external quality, internal quality, marketing qualify and symbolic quality of the menu and, the service group between 15~20 years as longer servicing period evaluate lower.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.713-721
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• 2006

Micro-drill wear deteriorates accuracy and productivity of the micro components. In order to improve productivity and qualify of micro components, it is required to investigate micro-drill wear exactly. In this study, a machine vision system is proposed to measure the wear of micro-drills using a precision servo stage. Calibration experiments are conducted to compensate for the machine vision system. In this paper, worn volume, area and length are defined as wear amounts. Micro-drill wear is reconstructed as the 3D topography and the quantized wear amount by using the shape from focus (SFF) method and wear parameters. Experiments have been conducted with HSS twist micro-drills and SM45C carbon steel workpieces. Validity of the proposed machine vision system is confirmed through experiments.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.71-72
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• 2006

This paper introduces the results of the development of a new mobile Digital DC-arc Welding Machine (DDWM). A simple PI controller is applied to the DDWM to control the output welding current tracking the constant setting current. Furthermore, a hot-start function, an anti-stuck function, a standby mode and an intelligential circuit breaker (ICB) are included in the DDWM. The DDWM increases welding quality and saves more power energy than a conventional welding machine. Because the DDWM is changed from ready mode into the standby mode automatically after 2 minutes interval from this unload start. Then the DDWM is changed into ready mode automatically since it is reused to weld. Mover, the DDWM increases welding qualify, productivity and reduces costs of welding. So, the DDWM can have a great of contribution to the mobile welding industries. The effectiveness of the DDWM was proven by the experimental results and durable test.

• Journal of Korean Society for Quality Management
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• v.30 no.1
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• pp.61-73
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• 2002

The Quality Function Deployment(QFD) is a Quality Management technique to maximize customers' satisfaction by reflecting customer requirements into all business processes, including concept definition, product planning, parts planning, process planning, production planning, and sales planning. The basic concept of the QFD is to translate customers' requirements appropriately into engineering characteristics, into parts characteristics, into process characteristics, and into specific requirements and activities in production. In this study, we reviewed and analyzed the application process of the QFD to the development of A2 FATC (Full Automatic Temperature Controller), an automotive component developed and produced by company A. It has been reported that by applying the QFD to the development of A2 FATC, company A. achieved 34% improvement in control robustness quality characteristic, 27% improvement in deviation quality characteristic, and 30% improvement in overall quality characteristics.

• Journal of Korean Society for Quality Management
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• v.34 no.2
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• pp.48-67
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• 2006

In this study, an investigation was done into service qualify factors of infant education Institutes, after which a positive verification was made in the relation of cause and effect between service quality, service value and customer satisfaction. Based on this verification, strategies were presented for plans to improve the service quality of infant education. In addition, identification was made into factors that affect customer satisfaction, re-registration intention and recommendation to others in putting forward service operational strategies for infant education institutes and making a comparative analysis on kindergartens and daycare centers.

• The Korean Journal of Food And Nutrition
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• v.6 no.1
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• pp.31-36
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• 1993

Strawberry pulp was separated into serum and insoluble pulp by centrifugation and the serum was concentrated in vacuo to five folds at 55~58$^{\circ}C$ and 30~60mmHg. Concentrated strawberry pulp was prepared by mixing of concentrated serum and insoluble pulp. To evaluate the quality changes of straw-berry pulp, color, physicochemical and sensory properties were analyzed after concentration and during 18 weeks storage at -18'2. The results obtained from the study were as follows : during 18 weeks storage at - l8$^{\circ}C$, soluble solid, browning, reducing sugar content were increased and total anthocyanin, vitamin C, apparent viscosity were decreased. The result of sensory evaluation indicated that texture of concentrated pulp was inferior to that of control but flavor, color intensity and overall acceptance were not different from each other.