• Environmental Analysis Health and Toxicology
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• 제19권2호
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• pp.227-233
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• 2004

The main objectives of this study were to identify from literature review the potential sources and to provide a preliminary national emission inventory for the unintentionally produced polychlorinated biphenyls (PCBs) (i.e., by - product PCBs). In Korea, fuel combustion, waste combustion, thermal industrial processes, and transportation were identified as potential sources of by -product PCB s. According to the availability of the emission factors and/or activity data, emission inventory could be assessed only for fuel combustion, waste combustion, steel industry, non-ferrous industry, and non-metallurgical industry. The total national emission of by-product PCBs was estimated to be 1087kg for the year 2000. The preliminary estimation further indicated that the steel manufacturing was the single dominant emission category, contributing 93％ to the total emission. Of the steel manufacturing processes, the contribution of the electric arc furnace was about 80％ of the total emission. Due to high uncertainty associated with both the emission factors and activity statistics, the emission estimates in this study are likely to contain significant errors. However, the results of the present work could serve the first step toward future efforts to establish national source and emission inventories of by-product PCBs.

• 한국식품조리과학회지
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• 제26권1호
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• pp.41-53
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• 2010

The purposes of this study were to: a) investigate personal and foodservice operational factors affecting job stress of school foodservice dietitians, b) analyze the contribution of emotional labor to job stress of school foodservice dietitians. A survey was conducted from May 2 to June 13, 2008 to collect data from school foodservice dietitians (N=546). 206 questionnaires were returned completed, and 15 improperly-completed questionnaires were excluded. Finally, 191 questionnaires were used for final statistical analysis (usage rate : 34.98%). The results of the study were as follows. First, personal variables significantly affecting dietitians' job stress were 'monthly bills(p<0.05)' and 'total length of time in school foodservice (p<0.05)'. Second, foodservice operational variables affecting dietitians' job stress were 'school level (p<0.05)', 'type of school foodservice management (p<0.01)', 'number of meal service times (p<0.05)', 'total number of meals served per day (p<0.001)', 'number of meals served per day for students (p<.001)', 'number of meals served per day for teachers (p<0.001)', and 'number of foodservice staff (p<0.001)'. Third, emotional labor was found to contribute significantly to the job stress of dietitians in school foodservice (p<0.001). It was found that as dietitians experience more emotional labor at work, more job stress is experienced. Stress management is a very important and meaningful contributor to foodservice quality as well as to personal well-being for workers in school foodservice. Therefore, it is proposed that management of emotional labor is essential for stress management. Further, emotional labor and job stress should no longer be considered a personal matter, but rather should be approached systematically in all aspects of a school foodservice organization.

• 한국식품조리과학회지
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• 제33권1호
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• pp.104-112
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• 2017

Purpose: This study aimed to analyze the contribution of emotional labor (surface acting, deep acting) and organizational commitment (affective commitment, continuance commitment) to turnover intention and customer orientation of school foodservice dietitian. Methods: Our survey was administered to 393 school foodservice dietitian in the Busan area on February 11, 2014. Results: For verification of mean differences, the mean scores for surface acting, deep acting, affective commitment, and continuance commitment were found to be 2.53/5.00, 3.71, 2.88, and 3.57, respectively. The mean surface acting score was significantly different according to age (p<0.001), total length of career as a dietitian (p<0.01), school type (p<0.001), and employment status (p<0.05). The mean deep acting and turnover intention scores were significantly different according to age (p<0.001), total length of career as a dietitian (p<0.001), school type (p<0.001), employment status (p<0.001), and no. of meals served (p<0.001). The mean customer orientation score was significantly different according to age (p<0.05), employment status (p<0.01), and number of work hour (p<0.05). There was a positive correlation (p<0.01) between turnover intention and surface acting and continuance commitment, but a negative correlation (p<0.01) with deep acting and affective commitment. Also, there was a positive correlation (p<0.01) between customer orientation and deep acting, affective commitment, but a negative correlation (p<0.01) with surface acting. Affective commitment had a negative influence on turnover intention (${\beta}=-0.444$, p<0.001), but surface acting had a positive influence on turnover intention (${\beta}=0.110$, p<0.05). Conclusion: These results suggest that management of affective commitment is essential for decreasing turnover intention. Therefore, emotional labor and organizational commitment of school foodservice dietitians should be managed from the school foodservice organizational viewpoint of The Ministry of Education.

• 한국병원경영학회지
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• 제19권1호
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• pp.21-31
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• 2014

This study aimed to find marketing strategy through comparison of internet homepage between national-public hospitals and private hospitals in Korea. A total of 51 hospitals' data were used with frequency, chi-square, t-test, multi-regression, correlation analysis. They were verified by SPSS Ver. 15.0 program. According to the result of this research, national-public hospitals operated more contents of public interests such as social contribution, volunteer work than private hospitals. Otherwise private hospitals operated more contents of costumer interests such as customer counselling, statistical data and cafe of customer voices than national-public hospitals. Synthetically we find that private hospitals try to get closer to the consumer than national-public hospitals. Because feedback and interaction between hospitals and consumer are very important, we suggest that national-public hospitals and private hospitals mutually should operate internet homepage in accordance with consumer needs of medical market.

• Journal of Mechanical Science and Technology
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• 제14권1호
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• pp.30-38
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• 2000

This paper presents a framework how to estimate crack driving forces in terms of crack-tip opening displacement and J-integral for mismatched dissimilar joints with interface cracks. The mismatch in elastic, thermal, and plastic hardening properties is not considered, but the mismatch in plastic yield strengths is emphasized here. The main outcome of the present work is that the existing methods to estimate crack driving forces for homogeneous materials can be used with slight modification. Such modification includes (i) mismatch- corrected limit load solutions, and (ii) evaluating the contribution of each material in dissimilar joints to the total crack driving force, which depends on the strength mismatch of the dissimilar joints.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1075-1078
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• 2005

Hydrogen adsorption on various porous materials have been studied with a volumetric method at low temperature in the pressure of 0-760 torr. Their hydrogen uptakes depend at least partly on microporosity rather than total porosity. However, it is also necessary to consider other parameters such as pore size and pore architecture to explain the adsorption capacity. The heat of adsorption and adsorption-desorption-readsorption experiments show that the hydrogen adsorption over the porous materials are composed of physisorption with negligible contribution of chemisorption. Among the porous materials studied in this work, SAPO-34 has the highest adsorption capacity of 160 mL/g at 77 K and 1 atm probably due to high micropore surface area, micropore volume and narrow pore diameter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.5143-5158
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• 2018

Improving the intrusion detection system (IDS) is a pressing need for cyber security world. With the growth of computer networks, there are constantly daily new attacks. Machine Learning (ML) is one of the most important fields which have great contribution to address the intrusion detection issues. One of these issues relates to the imbalance of the diverse classes of network traffic. Accuracy paradox is a result of training ML algorithm with imbalanced classes. Most of the previous efforts concern improving the overall accuracy of these models which is truly important. However, even they improved the total accuracy of the system; it fell in the accuracy paradox. The seriousness of the threat caused by the minor classes and the pitfalls of the previous efforts to address this issue is the motive for this work. In this paper, we consolidated stratified sampling, cost function and weighted Support Vector Machine (WSVM) method to address the accuracy paradox of ID problem. This model achieved good results of total accuracy and superior results in the small classes like the User-To-Remote and Remote-To-Local attacks using the improved version of the benchmark dataset KDDCup99 which is called NSL-KDD.

• 한국안전학회지
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• 제34권3호
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• pp.102-110
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• 2019

This paper describes the work and results of the preliminary Probabilistic Safety Assessment (PSA) for a research reactor in the design phase. This preliminary PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, eight typical initiating events are selected regarding internal events during the normal operation of the reactor. Simple fault tree models for the PSA are developed instead of the detailed model at this conceptual design stage. A total of 32 core damage accident sequences for an internal event analysis were identified and quantified using the AIMS-PSA. LOCA-I has a dominant contribution to the total CDF by a single initiating event. The CDF from the internal events of a research reactor is estimated to be 7.38E-07/year. The CDF for the representative initiating events is less than 1.0E-6/year even though conservative assumptions are used in reliability data. The conceptual design of the research reactor is designed to be sufficiently safe from the viewpoint of safety.

• 한국군사과학기술학회지
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• 제6권2호
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• pp.20-34
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• 2003

The good sea-keeping capability of the SWATH(Small Waterplane Area Twin Hull) ship has been attractive for research or surveillance vessels. Especially, for the naval ships accomplishing the underwater acoustic missions, it is necessary to access and minimize the underwater radiated noise level generated by the ships. Therefore, acoustic signature management and control are very important topics for these vessels. Underwater radiation pattern in the low frequency range is dominated by the tonals from the vibration of onboard machinery. In this work, the radiated noise level generated by the propulsion machine in the submerged hull is predicted using the transfer function technique and the hull transfer function for the submerged hull is determined by analyzing the longitudinal/circumferential stiffened infinitely long cylindrical shell and considering the empirical database of the previous vessels. It is confirmed that the transfer function technique can give useful information for identifying the noise source and estimating its contribution to the total radiatied noise level.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.54-61
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• 1997

Furthermore the rothor pole, with a solid type, manufactured by cold forging process at present should dmploy 3 press lines which consist of total 7 processes. Since A.S.B. treatment is prerequisite for the press line, the 3 times of A.S.B. treatment requires a long lead time, with little contribution to the reduction in cost. The author has investigated, through this researach, the possibility of a new forging method for a rotor pole production with (1) 2 pass instead of 3 press lines (2) only one A.S.B. treatment instead of 3 ones (3) solid type instead of sectional type, and (4) improvment of material property during process using a modified forging process and a specially designed die.