• Journal of Korean Society for Quality Management
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• v.44 no.2
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• pp.373-388
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• 2016

Purpose: This paper suggests a hierarchical time delay model to evaluate failure risks in FMEA(failure modes and effects analysis). In place of the conventional RPN(risk priority number), a more reasonable and objective risk metric is proposed under hierarchical failure cause structure considering time delay between a failure mode and its causes. Methods: The structure of failure modes and their corresponding causes are analyzed together with the time gaps between occurrences of causes and failures. Assuming the severity of a failure depends on the length of the delayed time for corrective action, a severity model is developed. Using the expected severity, a risk priority metric is defined. Results: For linear and quadratic types of severity, nice forms of expected severity are derived and a meaningful metric for risk evaluation is defined. Conclusion: The suggested REM(risk evaluation metric) provides a more reasonable and objective risk measure than the conventional RPN for FMEA.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.3
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• pp.341-347
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• 2017

This study was carried out to investigate the characteristics and Vitamin $K_2$ (MK-7) productivity of Cheonggukjang fermented by Bacillus subtilis SRCM100757 depending on the inoculum concentration 0.5% (v/w), 1% (v/w) and 2% (v/w). The lowest moisture content and water activity were $53.7{\pm}0.6%$ and $8.39{\pm}0.09$ after fermentation for 72 hours at 2% (v/w). pH slowly became alkalized during fermentation, but there was no significant difference. Amino nitrogen content increased with time and the highest content was $580.8{\pm}1.9mg%$ after fermentation for 72 hours at 2% (v/w). Lightness (L value) and yellowness (b value) decreased with time, whereas redness (a value) hardly changed. MK-7 contents increased with time at each inoculum concentration. The highest content was $20.47{\pm}1.53$ after fermeatation for 72 hours at 2%(v/w) and there were no significant differences between 1%(v/w) and 2%(v/w) inoculum concentrations.

• Food Science and Preservation
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• v.5 no.2
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• pp.177-185
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• 1998

For the purpose of enhanceing soybean-sprouts quality, the optimum conditions for ozone treatment of soybean during soaking before cultivation at 18~2$0^{\circ}C$ were evaluated with ozone concentration, treatment time and treatment frequency by response surface methodology. Germination rates of cleaned soybean by ozone water in the conditions of solubilized-ozone concentrations of 0.15 to 0.35ppm, ozone-treatment frequency of 1.5 to 2.3 times and ozone-treatment time of 30 to 36min. increased 18.8 to 24.0% for the control products. And, length of hypocotyl in conditions of 0.12 to 0.33ppm, 1.7 to 2.7 times and 45 to 90min. were also increased by 69.36 to 79.40%. On the other hand, weight of roots with ozone treatment were decreased in the conditions of solubilized ozone concentrations of 0.1 to 0.2ppm and ozone-treatment time of 30 to 57min. But, ozone-treatment frequency did not affected root growth. Putrefaction rates of the control were 5 to 15%, but those of ozone-treated samples during cultivation did not show. The overall optimum conditions for above 16% germination rates, above 9% hypocotyl yields compared to the control samples and below 98% of the control root weight were solubilized-ozone concentrations of 0.25 to 0.30ppm, ozone-treatment time of 43 to 49min. and ozone-treatment frequency of one time.

• Korean journal of food and cookery science
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• v.4 no.2
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• pp.71-79
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• 1988

This study is written to look into microbiological quality by passage of time and holding methods after making foods, by means of evaluating time, temperature and microbiological quality during various phases in product flow of cold soybean noodles serviced by an industry feeding operation for 500 persons a day, measuring pH & Aw and analyzing factors affecting microbiological growth conditions. The results were as follows: 1. According to phases in product flow of cold soybean noodles, it showed 15.6 hours of mean of needed time, $24.2^{\circ}C$ of room temperature, 5.1~7.6 of pH value & 0.95~0.98 of Aw except dry noodles. These conditions were good for multipling of microbe, and the phases with potential sanitary danger were ingredient, pre-preparation, holding before assembly and service and assembly & service. 2. As for holding methods and passage of time, holding at cold table was more effective than holding at room temperature as time past. 3. As for equipments using for making food, dipper, basket, kitchen board & kitchen towel showed high microbiological value in total aerobic plate counts and kitchen towel and stainless-steel were showed high microbioloical value in coliform counts. 4. E. coli, food poisoning bacteria was detected from barrel filled with soybean soup and also soybean itself.

• Geomechanics and Engineering
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• v.32 no.5
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• pp.503-512
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• 2023

In tunneling projects, a significant part of the costs is spent on segment production. By more economically producing, the cost of tunnel construction can be greatly reduced, especially in long and large-diameter tunnels. In the present study, the effect of using the Carousel method in the improvement of the production system performance compared to the conventional Static system has been studied. To carry out the research, a quantitative comparison of cost and production time was carried out for two production methods using the available documentation. The opinions of experts have been obtained using questionnaires and qualitative comparison of cost, time and production quality was done by implementation of statistical analysis. The SPSS software and the univariate t-test were used to analyze the questionnaires. According to the results of statistical analysis with SPSS, the use of the Carousel method will reduce production time and costs along with increasing manufacturing quality. According to the documentation analysis, the Carousel method reduces the cost of production by almost 30% and leads to a reduction of the production time to approximately 40% of the Static moulds system. The Carousel method has a higher production rate, efficiency, and better performance. Research into quantifying the benefits of Carousel method in the production system performance is very limited. This comparison is based on real information from the under construction Tabriz Metro project. This article can be very helpful in choosing the best production method.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.139-148
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• 2020

The purpose of this study is to propose a method to optimize the performance of Digital Radiography (DR) by analyzing the effect of exposure time change on the stability of radiation output and image quality. The experimental method was used to change the exposure time to 50 msec, 100 msec, 200 msec, and 400 msec so that the Percentage Average Error (PAE), Time-to-Radiation Dose Curve, Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR) and theses analysis were performed to evaluate the normal operation of parameters, radiation output and image quality. As a result, all the parameters used in the experiment showed the Percentage Average Error in the normal range, and the shorter the exposure time, the stability of radiation output and image quality decrease. In conclusion, it was found that the performance of Digital Radiography can be optimized when stable radiation output and image quality are applied by applying 100 msec ~ 200 msec exposure time.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.419-428
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• 2012

This study was carried out to analyze winter cereal crops for harvest time, proper drying time and haylage quality in order to investigate the possibility of the production of good quality haylage substitute for hay. As a result, in case of productivity and feed value, dry matter yield and TDN yield was increased with late harvest and crude protein and NDF, ADF was decreased (p<0.05). To make haylage for whole crop barley, oats, triticale, whole crop wheat need more than 32 hour wilting time in the milk ripe stage, yellow ripe stage need about 8~24 hour, and wilting time did not need the full ripe stage. Rye does not suitable for making haylage because of difficulty pre-wilting time. In case of fermentative quality on haylage, pH was increased with late harvest on all winter cereal crop forage. Lactic acid content was decreased with late harvest (p<0.05), and highest in the milk ripe stage. Acetic acid was also decreased with late harvest, and butyric acid was not detected. In conclusion, to harvest sooner of winter cereal crops could be an efficient way when making haylage in terms of protein content and fermentation quality. Ray can used as fresh and silage, because difficulty for pre-wilting time in Korea. Whole crop barley, oats, triticale, wheat can be used haylage when harvested yellow ripen stage and pre-wilting time for 8~24 hours.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.180-187
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• 1998

This paper is to reduce implementation time of POS system by applying QFD. All the related elements are classified by the hierarchical structure into three phases: expected quality, weight and evluation. The mentioned about includes the first and second improvement, and the case study of POS system of petrol stations in Taichung. The results of this research are shown in the following. 1. the first improvement was from average 76 days/station to 48 days/station. 2. the second improvement was from average 48 days/station to 36 days/station. 3. the ratio of target achievement was $162\%$

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.289-292
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• 2002

This paper provides a frame-layer method for controlling bit rate of compressed video data in real time. Our approach is easy to operate and can store encoded video data in real time without deteriorating the quality of an image. To provide ameliorated and consistent visual quality, a new concept named SOP (Set Of Pictures) and a new quantization parameter variation control algorithm based on a second-order rate-distortion model 〔2〕 are introduced. The total bit-budget is allocated efficiently to cope with unpredictable recording time by using the proposed algorithm and it is distributed to each frame. In the end, we show improved and consistent video quality with experimental results obtained from C-model of a MPEG-4 (simple-profile) encoder.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1040-1043
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• 2004

As time goes by, the market demand increases and each LCD panel manufacturing company makes every effort to produce more panels in a limited time. It is necessary to reduce the cost and time of production for the improvement of productivity in manufacturing companies. The increased speed of thin films growth used in the TFT process brings improvement of productivity but it is also accompanied by a drop in display quality due to a characteristic change of the thin film. So in our dissertation, we deal with the increased speed of a-Si layer growth and the proportioned a drop in characteristic quality. We discuss a drop in display quality by a characteristic change of a-Si layer and we propose a counter-plan through panel design improvement. We have already applied our plan to the 15" XGA panel and confirmed the improved result.