• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.163-167
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• 2017

The service life extension of the missile can reduce the replacement cost of the missile, maintain the combat power, and consist of the lifetime assessment of the shelf-life(energetic) items, the maintenance of the missile and upgrade of the related components. This technology should be developed together with the missile system and advanced sustainedly. It is a converging technology that combines various fields of expertise and long-term experiences and databases.

• Korean Institute of Interior Design Journal
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• v.17 no.3
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• pp.51-58
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• 2008

Lately, in public libraries, there are various service programs for child user by corresponding to importance of reading based education and also a variety of changes by accommodating family based cultural life style. Therefore there is a need for space planning based study on unit-data room. This study gives guide-line of space planning through categorizing of space plot and furniture lay-out in child data room. The researcher, as a first step, searched web sites of 29 data rooms of 26 libraries and summarized space plots and features of data rooms through in-person visits. Then the author made a categorization standard and did a general analysis of featured data rooms through multiple categorization steps. There are Basic Type, General Type, Book-Shelf Centered Type, Book-shelf Scattered type and Multi-Functional Type out of this categorization steps. In sum, six categorizing bases, dividing infant room from child room, space zonning, position of entrance, compactness of reading space, position of book-shelf and orientation of book-shelf will be important design standards for child data-room of future libraries and an effective guide-lines for other unit data-rooms.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.148-153
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• 2017

During natural ageing of HTPB propellant undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behaviour at different time-temperature conditions especially focused on the in-service conditions. Ageing behaviour of HTPB propellant were investigated using HFC(Micro-Heat Flow Calorimeter) is universal technique for measuring the rate of slow chemical and physical processes in long-term storage.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.59-65
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• 2018

During natural aging, hydroxyl-terminated polybutadiene(HTPB) propellant undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behavior at different time-temperatures focusing on in-service conditions. Aging behaviors of HTPB propellant are investigated using HFC(heat flow calorimeter), a universal technique for measuring the rate of slow chemical and physical processes in long-term storage.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.25-34
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• 2015

Recently, in distribution market, demand for electronic shelf label system is increasing gradually to provide the accurate price immediately and detailed product information to consumers and reduce operation costs. Most of electronic shelf label system companies develop the full-graphic display device to display a wide variety of product information as well as the exact price. Our system had introduced Go-Back-N retransmission method in the early. However, we encountered performance problems that it delayed updating of the electronic shelf label system and exhausted the battery life time. Proposed adaptive image retransmission technique based on the selective scheme is that tags of electronic shelf label system recognize idle time of transmission cycle and require partial image retransmission to sever by itself. As a result, it can acquire much more opportunities of partial image retransmission within the same period and increase reception rate of full image for each tags. The experimental result shows that adaptive image retransmission technique's reception rate of full image for each tags is approximately 4% higher than existing previous works. And total battery life time increases 30 hours because tag reduce wake-up time as it receive only lost data instead of whole data.

• Journal of Applied Biological Chemistry
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• v.62 no.2
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• pp.181-186
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• 2019

The optimum design of LED device for irradiation of 460 nm blue light on extruded rice cake using simulation and the effect of the blue light on the inactivation of Bacillus cereus (B. cereus) group on the rice cake were investigated. The irradiated light intensity patterns on the surface area of the sample were simulated with three different LED arrays (centered, cross, and evenly spaced) and at various distances (22, 32, 42 mm) between the LED modules and the sample. In addition, the uniformity was calculated as Petri factor. The evenly spaced array resulted the most uniform light intensity pattern in the simulation, and the Petri factor of 32 and 42 mm of the distances showed higher than 0.9, which represents the ideal uniformity of LED device. The bacterial population of the rice cake decreased to less than the initial bacterial population during exposure to LED blue light, whereas the bacterial population of the control sample increased. The bacterial count of the rice cake after blue light irradiation for 24 h was 1.21 log CFU/g lower than the control sample. Petri factor increased with increase of the distance between the light source and sample, however, the reduction rate of B. cereus group decreased. Therefore, the design of LED device, that represented the Petri factor higher than 0.9 and inactivated the population of B. cereus group, with evenly spaced and 32 mm of distance between the light source and sample was suitable for extending shelf-life of rice cake.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.17-25
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• 2014

The purpose of this paper is to present a method to estimate the storage life of propellant bag for degradation of breaking load with storage time by using gamma process model. The nitrogen compound generated by natural decomposition of propellants degrades the breaking load of propellant bag with time. The statistical distributions of condition and lifetime with time were shown from the results of accelerated life test of propellant bag cloth at $80^{\circ}C$. It was found that the use of median for life was highly appropriate and the $B_1$ or $B_5$ life should be selectively applied to the quality assurance policy.

• Archives of design research
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• v.14 no.2
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• pp.245-252
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• 2001

On the assumption that the layout of refrigerator for domestic market does not match with the eating habits of the Korean, this study suggests a way of improvement for usability of the refrigerator by re-arranging layout of inner shelves through behavioral analysis with the video ethnography. On the result of analysis, it can be found that the layout of inner shelves of the most refrigerators differs from the habits of cooking and preparing meals of Korean food, so the author propose a new layout to exchange the usage of the 3rd shelf with the vegetable box of the bottom level. It can be effective method to improve the usability by assigning appropriate usage for each shelf. To extract internal design factors of product, which is related to the specific living habits such as a refrigerator, understanding of user behavior must be accomplished at the first stage. The author found that the analysis of user behavior using the video ethnography is useful for this purpose, because it can be used to explore unpredictable design factors from user's real life.

• Journal of Distribution Science
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• v.11 no.10
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• pp.107-116
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• 2013

Purpose - Eggs are nutritionally complete and one of the most popular natural foods. Moreover, the poultry industry is one of the important food industries. However, early industrialization of the poultry industry on its own did not lead to further development compared to other livestock industries. In this study, we investigate what factors influence consumers' behavior and how consumers' understanding of retail business affects their propensity to consume. This study is different from other studies as it analyzes how the brand names of manufacturers and distribution companies affect the purchasing characteristics or actual purchase behavior of consumers in order to suggest how these manufacturers and distribution companies can increase their competitiveness. Research design, data, methodology - This study conducted a survey of 250 randomly selected egg purchasers in discount stores from January to April 2013. Consumers' purchase tendencies were calculated through frequency analysis. This result was then utilized using cluster analysis to draw a conclusion about which purchase tendency influenced consumers buying three different brands of eggs or whether this tendency really affected consumers. As a result, the outcomes of Hypotheses 2 and 3 were not clear so we drew a conclusion with our analysis of Hypothesis 1. Results - While the outcomes of Hypotheses 2 and 3 did not clearly indicate whether purchasing tendencies affected consumers when buying eggs, our analysis of Hypothesis 1 indicated that consumers were affected by the quality of the eggs rather than exterior factors such as the brand name. Thus, we concluded that it is important to promote the excellence of the quality of the eggs. Usually firms buy eggs from farms and repackage them in order to sell them. In this sense, if consumers were aware of this egg production process, and eggs were fairly distributed to retailers, large retail PB businesses would also be able to enhance their competitiveness. Conclusions - The brand, packaging, retail outlet, and other external features influenced the purchase of eggs to a certain degree, while shelf life, grade of the eggs, cleanliness, and other intrinsic characteristics had more influence. In particular, shelf life was the most important factor influencing purchase. Consumers were influenced not only by intrinsic characteristics of the eggs but also by large-scale producers' brands. Consumers relied upon the brand despite reduced competition because they found it difficult to identify shelf life and/or cleanliness. Small businesses and/or large-scale retailers can remain competitive by maintaining the freshness and cleanliness of the eggs. Further studies need to investigate areas in which consumers' cognition of the product is poor and/or the purchase inclination with regard to less developed industries such as eggs. In this study, the greatest problem was that consumers did not consume in accordance with the current situation as consumers have preferred fresh and clean eggs for a long time compared to purchase decisions based on external brands and/or packaging.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.56-67
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• 2006

The reliability and failure mode effect analysis are effective means to achieve efficient and cost-reduction design for satellite development. The failure rate of COTS (Commercial-Off-The-Shelf) parts required for reliability analysis is not usually provided from the manufacturer. Space environment factors based on empirical data obtained from MIL-HDBK-217F can be applicable to the reliability calculation. As a radiation environment factor, the occurrence rate of SEL (Single Event Latch-up) is additionally incorporated for the failure rate prediction. In this paper, the statistical reliability analysis method for low-cost small satellite using COTS parts is suggested. This statistical reliability analysis was applied to HAUSAT-2 small satellite whose electronic boxes are consisted of many COTS parts to calculate the system reliability at the end of design mission life.