• Progress in Medical Physics
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• v.29 no.3
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• pp.92-100
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• 2018

The manufacturer of a linear accelerator (LINAC) has reported that the target melting phenomenon could be caused by a non-recommended output setting and the excessive use of monitor unit (MU) with intensity-modulated radiation therapy (IMRT). Due to these reasons, we observed an unexpected beam interruption during the treatment of a patient in our institution. The target status was inspected and a replacement of the target was determined. After the target replacement, the beam profile was adjusted to the machine commissioning beam data, and the absolute doses-to-water for 6 MV and 10 MV photon beams were calibrated according to American Association of Physicists in Medicine (AAPM) Task Group (TG)-51 protocol. To verify the beam data after target replacement, the beam flatness, symmetry, output factor, and percent depth dose (PDD) were measured and compared with the commissioning data. The difference between the referenced and measured data for flatness and symmetry exhibited a coincidence within 0.3% for both 6 MV and 10 MV, and the difference of the PDD at 10 cm depth ($PDD_{10}$) was also within 0.3% for both photon energies. Also, patient-specific quality assurances (QAs) were performed with gamma analysis using a 2-D diode and ion chamber array detector for eight patients. The average gamma passing rates for all patients for the relative dose distribution was $99.1%{\pm}1.0%$, and those for absolute dose distribution was $97.2%{\pm}2.7%$, which means the gamma analysis results were all clinically acceptable. In this study, we recommend that the beam characteristics, such as beam profile, depth dose, and output factors, should be examined. Further, patient-specific QAs should be performed to verify the changes in the overall beam delivery system when a target replacement is inevitable; although it is more important to check the beam output in a daily routine.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.478-486
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• 2020

The purpose of this study was to find out the actual status of smartphone students' dependence on college students, and to identify the correlation between depression, self-efficacy and smartphone overdependence, and the role of self-efficacy in the relationship between depression and smartphone overdependencee. The main results of the survey and analysis of 1,177 four-year college students located in Gyeonggi area are as follows. First, the percentage of college students' smartphone overdependence was very high at 34.1%. Second, there was a significant difference in prevalence of depression between the smartphone overdependence group(18.7%) and the general user group(11%). Third, self-efficacy showed a negative correlation with smartphone overdependence. The smartphone overdependence group showed significantly lower score in self-efficacy and self-regulation efficacy, confidence, and task difficulty preference than the general user group. Fourth, self-efficacy worked as a mediating variable in the relationship between depression and smartphone overdependence. In other words, the effect of depression on smartphone overdependence tended to decrease as self-efficacy rose in the relationship. Finally, we discussed the development of programs to support career and psychological counseling of university students.

• Journal of Navigation and Port Research
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• v.33 no.8
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• pp.563-572
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• 2009

The steel industry, as the national representative strategic industry of our country, has played the motive power for the economic growth of Korea in 1970s as the positive support of the government and the management endeavor of the private were harmonized. However, in case of our country, we have mostly relied on import of the raw materials for the steel industry, and as the weight of the imported raw materials is heavy, the steel industry is the industry whose transport burden is big as it is called 'transport industry'. So, the transport rationalization will be the important task of the steel industry. This study has analyzed the economic efficiency per the transport route (container ship vs bulk ship) of the sea transport related to import/export of the steel scrap on the level acquiring the stable supply of the steel scrap. For this, this study firstly researched the status of domestic/foreign steel industry. And analyzed the world crude steel production volume, steel scrap consumption volume and world steel scrap trading structure. Also, in order to compare the transport logistics expenses between two transport devices, namely, container ship and bulk ship, this study calculated the logistics expenses per ton by using the traffic hours and traffic expenses items as the imported/exported scrap freights of 'D' company.

• Land and Housing Review
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• v.2 no.3
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• pp.249-258
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• 2011

In order to achieve an efficient urban regeneration of the nation, it is required to determine the extent of decline nation-wide and the declined areas for each district and also to evaluate the potentials of the concerned areas. For this task to be accomplished, a construction of a comprehensive diagnostic system based on spatial information considering diversity and complexity is required. In this study, a total information system architecture for urban regeneration is designed as part of the construction of such a diagnostic system. In order to develop the system, a city and district level unit decline diagnostic indicators has been constructed and a decline diagnostic system has been developed. Also, a scheme to promote the advancement of the system is proposed. The DB construction is based on the city and district level nation-wide and metadata for the concerned level is constructed as well. The system is based on the Open API and designed to be flexible for extension. Also, an RIA-based intuitive UI has been implemented. Main features of the system consist of the management of the indicators, diagnostic analysis (city and district level decline diagnosis), related information, etc. As for methods for the advancement, an information model in consideration of the spation relations of the urban regeneration DB has been designed and application methods of semantic webs. Also, for improvement methods for district unit analytical model, district level analysis models, GIS based spatial analysis platforms and linked utiliation of KOPSS analysis modules are suggested. A use of a total information system for urban regeneration is anticipated to facilitate concerned policy making through the identification of the status of city declines to identify and the understanding of the demands for regeneration.

• Tunnel and Underground Space
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• v.19 no.5
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• pp.373-387
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• 2009

Considering the current construction technology and research status of deep repository tunnels for radioactive waste disposal, it is inevitable to use cementitious materials in spite of serious concern about their long-term environmental stability. Thus, it is an emerging task to develop low pH cementitious materials. This study reviews the state of the technology on low pH cements developed in Sweden, Switzerland, France, and Japan as well as in Finland which is constructing a real deep repository site for high-level radioactive waste disposal. Considering the physical and chemical stability of bentonite which acts as a buffer material, a low pH cement limits to $pH{\leq}11$ and pozzolan-type admixtures are used to lower the pH of cement. To attain this pH requirement, silica fume, which is one of the most promising admixtures, should occupy at least 40 wt% of total dry materials in cement and the Ca/Si ratio should be maintained below 0.8 in cement. Additionally, selective super-plasticizer needs to be used because a high amount of water is demanded from the use of a large amount of silica fume.

• Korean Security Journal
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• no.20
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• pp.229-248
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• 2009

This research is looking for the private security industry and diagnostic issues and enable our strategy will be presented through SWOT analysis for the management environment of private security industry to ultimately contribute to the private security industry. Along, the purpose of this research is to want to reach key factors which affect the competitiveness of the private security industry. This study was to conduct literature research and surveys. And analyzing literature and data was collected. And determined the status of private security industry by conducted a comprehensive survey with 13 experts is causal. The question investigation hemisphere the question which harmonizes became accomplished in the center. Like this question analyzed the opinion of the identical research participant and 3 times was executed repetitively, and 2 to verify the data through multiple data as a basis for the SWOT analysis of the environment. Accordingly, the following conclusion emerges. First, the private security industry-related legislation will complement the systematic. This is the task of the public security authority and the relationship will be in the direction for improvement. Second, to develop strategies for diversification of products and services through the use of IT. This business what development security services and products based on IT advanced technology can provide a solution to maximize profits to large security companies and to all of the small companies. Third, it should seek ways to make exports that social safety net project based on security technology and capital of Kore for other Asian countries or developing countries in the world.

• Korean Security Journal
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• no.39
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• pp.355-386
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• 2014

Current business environment asks the fundamental changes about business security. The essences of these changes are that the security management of today's global business is important task of managers and the security practitioner is professional who needs very specialized education and training with business thinking. Rapid process of globalization of global village tore down the business limit that was restricted on the geological areas' limitation. Rapid business environments' change that is driving depends on development of science and technology with globalization needs new paradigm to keep business continuity. With the process of globalization, Korea, which importance is gradually increasing in the national economy, has trade dependent economic system, which keeps power of national economy through trade, so Korean economic tendency is accelerating. To keep competitiveness in global market, new strategy that is different with existing domestic business management is necessary. That is, capacity of coping with outside risk in domestic business management is established in some degree, but business activities in foreign countries faces at numerous unexpected risks that differ from country to country such as difference with the custom, changes of corporate governance etc. To cope with these new risks effectively, new paradigm for business risk is necessary. Especially, flexibility of thinking like new paradigm is necessary to cope with new security risk effectively. To cope with security risk that occurs in the new business environment effectively and competes against international company in global market, company management and members' changes of cognition about security and innovative changes in security policy is necessary. In the basement of these changes, there is expansion of business security tasks, improvement of report line, enhancement of professionalism and status of security officers, variation of hands-on workers and increasing of investment to the security etc.

• Journal of Technology Innovation
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• v.22 no.2
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• pp.1-30
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• 2014

Offset trade has been applied in Republic of Korea's defense acquisition programs since early 1980s and used for national economic development as well as enhancement of military capabilities. The accumulated offset trade value amounts to over 10 billion dollars by 2010. However, questions in regards to the effectiveness of offset trade have been constantly raised. As it is a quite difficult task to analyze and calculate the application performance of defense technologies acquired by offsets objectively, limited level of quantitative analysis of application performance have been conducted so far. Hence, in this paper, we came to understand the overall status of application of those technologies through in-depth performance analysis and suggested some specific policies for the further development of offset trade based on the analysis results. To begin with, we developed a questionnaire based on performance indicator deducted through literature review of relevant researches, and conducted survey of major offset recipients. Also, another survey of offset experts belonged to the army, government organization, research institute and companies was conducted to evaluate the performance and effectiveness of offsets qualitatively. And we analyzed the efficiency of application performance using DEA. The results of all surveys are showing that there is positive accomplishment in the technological aspect, but in economic aspect, it shows relatively inactive outcome. Based on these results, policy direction is considered to be changed from the emphasis on the acquisition of core technology to revitalization of domestic defense industry in line with new government's policy orientation.

• Journal of the Korean Society of School Health
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• v.6 no.1
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• pp.45-57
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• 1993

The purpose of this study was to survey the current status of informal health education which elementary school nurses have performed in these days. The questionaire survey in this study was obtained from 154 (74.0%) out of 208 elementary school nurses in Kyungbuk province. This study is about their health educational conditions, contents, attitudes. The results are summarized as follows. 1. General characteristics of respondents 1) As for age distribution, thirties with 56.5% is larger than any other group 2) As for school size, below 18 classes with 48.1% is the highest 3) As for the place in which the work, country side (below county) with 65.7% is the highest 4) 89.6% of total respondents have graduated from nurse college 5) Their total career below 10 years is 68.2% 6) Their clinical career below one year is 35.7% 2. Actual conditions of health education 1) The rate of respondents who execute health education is 75.3% out of 154 respondents 2) Health education does not execute because the task of school nurses is busy. This percentage is 55.3% 3) Respondents who draw up a yearly health education plan are 84.5% 4) Weekly health education classes with 1~2 times are 79.3% and teaching time with 89.7% is physical class. 5) 75.0% of total respondents don't use the textbook in health education and the reason is that the contents of nextbook are poor. 6) In health education, teaching aids with VTR, slide flims, charts etc. are 80.2% 7) 82.8% of total respondents don't evaluate the result of teaching 3. Analysis of contents of health education and attitudes of school nurses. 1) The rate of private sanitation for keeping health with 64.7% is high among the contents 2) 90.9% of total respondents demand health education and 92.9% of then demand its independence of a subject. 3) The degrees of school principals' help and understanding are 90.3%, and those of teachers are 89.6% 4) The degrees of school nurses' confidence are high at 35.1% 5) Regular health education classes a week of a school nurse with 3~4 times are 40.9% 6) The greatest difficulty in health education with 70.1% is lack of teaching aids.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.71-82
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• 2018

Stress involves changes in behavior, autonomic function and the secretion of hormones. Autonomic nervous system (ANS) contributes to physiological adaptive process in short durations. In particular, heart rate variability (HRV) analysis is commonly used as a quantitative marker depicting the ANS activity related to mental stress. The aim of this study is to investigate correlations between psychological responses to stress and HRV indices induced by the cognitive stressor. Thirty-three participants rated their mental and physical symptoms occurred during the past two weeks on Stress Response Inventory (SRI), which is composed of seven stress factors that may influence the status of mental stress levels. Then, they underwent the psychophysiological procedures, which are collected electrocardiogram (ECG) signals during a cognitive stress task. HRV indices, the standard deviation of R-R interval (SDNN), root mean square of successive R-R interval difference (RMSSD) and low frequency (LF)/high frequency (HF) ratio were extracted from ECG signals. Physiological responses were calculated stress responses by subtracting mean of the baseline from the mean of recovery. Stress factors such as tension, aggression, depression, fatigue, and frustration were positively correlated to HRV indices. In particular, aggression had significant positive correlations to SDNN, RMSSD and LF/HF ratio. Increased aggressive responses to stress correlated with the increases of all HRV indices. This means the increased autonomic coactivation. Additionally, tension, depression, fatigue, and frustration were positively associated with RMSSD reflecting increases in parasympathetic activation. The autonomic coactivation may represent an integrated response to specific cognitive reactions such as the orienting response.