• Journal of Biosystems Engineering
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• v.24 no.1
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• pp.19-24
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• 1999

Motivated by the need for developing the more efficient lighting system for light culture of strawberries in the greenhouse, this paper aims at acquiring and suggesting more concrete and scientific foundation of illuminating position, numbers of light source by investigating the types of lighting system and illumination distribution in the greenhouse for light culture of strawberries. The results of investigation and experiment are summarized as following below: 1. The types of lighting system used in the greenhouse producing strawberries were classified as 1 line and 2 lines lighting system. 2. As for the arranging types of artificial light, 2 lines lighting system, were classified as Z-type, N-type and W-type. (Refer Fig. 3) 3. The results of illumination distribution for Z-type, N-type and W-type of 2 lines illuminating system in the greenhouse with a small size tunnel measured at the height of 1.5m from the ground with 220V, 100W lamp in 6m light gap showed that maximum illuminance are 961x, 1211x, 1251x, minimum illuminance are 4.41x, 4.71x, average illuminance are 33.71x, 43.11x, 44.51x and standard deviations are 28.31x, 35.41x, 38.31x at each types. 4. Proportion of the area below optimal illuminance to floor area at the two lines illuminating system of Z-, N-, and W-type in greenhouse were appeared as 39.4%, 26.0% and 26.3%, respectively. Also proportion of the area over optimal illuminance to floor area at the two lines illuminating system of Z-, N-, W-type in greenhouse were appeared as 16.8%, 14% and 14.7%, respectively. Thus N-type was superior to the others from the view points of optimal illumination distribution and energy saving.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.53-62
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• 2015

LWDT was developed for use as an alternative technique to measure the stiffness of trackbed soils. In this study, numerical and theoretical analyses of LWDT's acting mechanism were performed. The effectiveness of the adapted elastic formula used for calculation of the dynamic modulus, Evd, was investigated theoretically and also numerically by running ABAQUS analysis. The minimum thickness of the upper layer is proposed based on the analysis. Correction factors for the formula of elastic modulus are also proposed in this study. In the future, following field test results and laboratory mechanical tests such as the resonant column test, a guideline for the use of LWDT as a standard test protocol in track construction sites, as a measuring tool for the degree of compaction and/or stiffness and dynamic modulus, will be proposed based on this analysis.

• Journal of Radiation Protection and Research
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• v.46 no.3
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• pp.106-111
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• 2021

Background: Crookes tube is utilized in junior high and high schools in Japan to study the character of electrons and current, and not for radiological education. There is no official guideline or regulation for these radiation source to the public. Therefore, most teachers have no information about the leakage of X-rays from Crookes tube. The peak energy of X-rays is approximately 20 keV, and it is impossible to measure using conventional survey meters. Materials and Methods: Each leakage dose of low energy X-rays from 38 Crookes tube in the education field, such as junior and senior high schools in Japan, was explored by the teachers in the school using radio-photoluminescence (RPL) dosimeters. Before and after the measurements, the dosimeters were sent by postal mails. Results and Discussion: At the exploration in this study, it was estimated that the 70 ㎛ dose equivalent, H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes, at the distance of 1 m, where the Crookes tube was usually observed. However, the highest dose was estimated as 0.69 mSv by an equipment with the full power. Furthermore, one Crookes tube exhibited 0.62 mSv with minimum output power of the induction coil. This relatively large dose was reduced by the shorter distance of discharge electrodes of the induction coil. Conclusion: The leakage dose of low energy X-rays from 38 Crookes tube was explored using RPL dosimeters. It was estimated that the H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes at the distance of 1 m, while some equipment radiated a higher dose. With this study, the provisional guideline for the safety operation of Crookes tube is established.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.203-212
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• 2018

Quality requirements of manufactured products or parts are given in the form of specification limits on the quality characteristics of individual units. If a product is to meet the customer's fitness for use criteria, it should be produced by a process which is stable or repeatable. In other words, it must be capable of operating with little variability around the target value or nominal value of the product's quality characteristic. In order to maintain and improve product quality, we need to apply statistical process control techniques such as histogram, check sheet, Pareto chart, cause and effect diagram, or control charts. Among those techniques, the most important one is control charting. The cumulative sum (CUSUM) control charts have been used in statistical process control (SPC) in industries for monitoring process shifts and supporting online measurement. The objective of this research is to apply Taguchi's quality loss function concept to cost based CUSUM control chart design. In this study, a modified quality loss function was developed to reflect quality loss situation where general quadratic loss curve is not appropriate. This research also provided a methodology for the design of CUSUM charts using Taguchi quality loss function concept based on the minimum cost per hour criterion. The new model differs from previous models in that the model assumes that quality loss is incurred even in the incontrol period. This model was compared with other cost based CUSUM models by Wu and Goel, According to numerical sensitivity analysis, the proposed model results in longer average run length in in-control period compared to the other two models.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.3
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• pp.161-172
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• 2019

This study examines the characteristics and recent changes of the Hanbok industrial cluster in Gwangju Metropolitan City, in order to understand the problems in the activation of the Hanbok industry and to seek future policies. A total 32 companies comprise the 'Small Manufacturer Specialized Support Center of Hanbok' and were surveyed with a 41 questions with questions in four categories. The Gwangju Hanbok area has been in existence for more than 40 years and was composed of small groups of one or two manufacturers. They are experiencing the same difficulties as other Hanbok clusters, such as the aging of workers, the downturn of dress culture, and changing consumption paradigms. However, since 2015, various efforts have been made in order to seek countermeasures to cope with such difficulties, particularly with the foundation of the 'Small Manufacturer Specialized Support Center of Hanbok' with the support of the Ministry of Small Venture Business. This study focuses on the alterations in the current Hanbok industry due to the IT industrialization as well as the changes in the locations of the Hanbok clusters due to the revitalization of old towns by local governments., The results providing an opportunity to appreciate the problems therein and seek the solutions. Small manufacturers of the Hanbok cluster are trying to improve their entrepreneurship, digital technology application, and knowledge in accordance with the socio-economic trends, but they have limitations to practically apply it to business, barely keeping the minimum production base. The central government and the Gwangju should reinforce and expand the support for marketing and public relations for the Hanbok to foster the designer population, to establish mutual brands, to raise brand awareness, and to promote the technological perfection of the individual businesses, to allow them to cope with the current market trends, in order for the technological development and firm settlement of the local Hanbok industrial cluster.

• Journal of the Society of Disaster Information
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• v.15 no.1
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• pp.98-108
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• 2019

Purpose: The purpose of this study is to test the sprinkler performance to protect the wall and ceiling joints of the sandwich panel warehouse in case of fire. Method: Based on the field surveys, test was setup and combustibles were prepared. The sprinkler discharge tests were performed at the corner of the wall and right under the sprinkler head. Results: It has been found that operation of the K-80 closed sprinkler head prevents the ignition of the sandwich panel and therefore no damage to the joints of sandwich panels. To prevent skipping phenomenon, it is necessary to install the sprinkler head from the corner of the wall and to keep a minimum distance of 2.4m and a maximum distance of 3m. Conclution: A Standard Operation Procedure should be prepared to suppress and rescue of fire brigade for a sandwich panel warehouse protected by perimeter sprinklers preventing a ignition of core materials and control fire.

• Journal of Industrial Convergence
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• v.20 no.6
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• pp.37-45
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• 2022

With the development of the Internet of Things (IoT), related network infrastructures require new technologies to protect against threats such as external hacking. This study proposes an L-PBFT consensus algorithm that can protect IoT networks based on a blockchain consensus algorithm. We designed a blockchain (private) model suitable for small networks, tested processing performance for ultra-small/low-power IoT devices, and verified stability. As a result of performance analysis, L-PBFT proved that at least the number of nodes complies with the operation of the consensus algorithm(minimum 14%, maximum 29%) and establishes a trust network(separation of secure channels) different from existing security protocols. This study is a 4th industry convergence research and will be a foundation technology that will help develop IoT device security products in the future.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.619-644
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• 2022

The purpose of this study is to estimate the economic benefit of improving ground water quality in Jeju Island, where groundwater pollution has recently become a social issue and various water quality improvement projects are being promoted. By applying the contingent valuation method, an online survey was conducted on Jeju Island residents to analyze the response data of 542 respondents and estimate the mean willingness to pay using 16 models. The estimation of the double-bounded dichotomous choice model confirmed that each household was willing to pay 28,008 won per year, with the willingness to pay estimated at a minimum of 17,762 won and a maximum of 37,416 won based on different models. The total annual benefit for Jeju Island's ground water quality improvement was estimated to be about 8.66 billion won , and socioeconomic factors influencing willingness-to-pay were investigated. This study is expected to serve as a foundation for the development of environmental improvement policies by assisting in the understanding of Jeju Island's unique water resource environment.

• The Research Journal of the Costume Culture
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• v.30 no.6
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• pp.828-841
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• 2022

This study aims to develop a fitted torso pattern suitable for males in their forties and fifties who are obese-a group that accounts for more than fifty percent of men in this age group-using a 3D virtual fitting program. Size Korea's 2022 data for obese males in their forties and fifties is utilized for this study. In terms of the research method, a 3D program (CLO 3D) is used to implement the target group's various body types and to apply fitted torsos that enable verification and evaluation of the pattern's fit and ease. The characteristics of fitted torso patterns for obese bodies are as follows: the front centerline is a profile line; shoulder darts are added by reflecting waist-abdominal protrusion in the front panel; and shoulder, arm, waist, and center-back darts are constructed for the back panel. For obese bodies, the minimum circumference ease amounts should be approximately 6-7cm for the chest, 6cm for the waist, and 6-7cm for the hips. Based on an evaluation of the virtual fit of the developed fitted torso pattern, the data shows that a pattern (foundation) such as this is well suited for obese body types with an average of 4.67/5 points for reverse triangular obesity, an average of 6.67/7 points for log obesity, and an average of 6.69 points for the ease amount.

• Korean Journal of Social Welfare Studies
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• v.42 no.1
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• pp.279-304
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• 2011

The housing is basic need to human life, foundation of family life and structural characteristics to control human life and action. The structural characteristics of housing have various effects on the family life such as family lifestyle, relationship of family members and child development and health by family structure. The purpose of the study is to identify how the housing poverty, defined as sub-minimum standard housing conditions, excess housing expenditure and housing instability, affects the family responsibility burden, the family relationship satisfaction and the family life satisfaction. This study used the third Korean Welfare Panel Study, the analytic method used was the Structural Equation Modeling(SEM), and the model fit had a considerable validity by inspecting the SEM. The findings of the study are as follows. Housing poverty had significant positive effect on family responsibility burden, while had significant negative effects on family conflict action method, family relationship satisfaction, family life satisfaction and health(subjective, mental, physical). The indirect effects on housing poverty had better effect by family conflict action method than effect by health, but the direct effects had the most.