• Nuclear Engineering and Technology
• /
• v.51 no.1
• /
• pp.176-189
• /
• 2019

This paper presents a feasibility study for producing the medical isotope $^{99m}Tc$ using the hazardous and currently wasted radioisotope $^{99}Tc$. This can be achieved with the nuclear resonance fluorescence (NRF) phenomenon, which has recently been made applicable due to high-intensity laser Compton scattering (LCS) photons. In this work, 21 NRF energy states of $^{99}Tc$ have been identified as potential contributors to the photo-production of $^{99m}Tc$ and their NRF cross-sections are evaluated by using the single particle estimate model and the ENSDF data library. The evaluated cross sections are scaled using known measurement data for improved accuracy. The maximum LCS photon energy is adjusted in a way to cover all the significant excited states that may contribute to $^{99m}Tc$ generation. An energy recovery LINAC system is considered as the LCS photon source and the LCS gamma spectrum is optimized by adjusting the electron energy to maximize $^{99m}Tc$ photo-production. The NRF reaction rate for $^{99m}Tc$ is first optimized without considering the photon attenuations such as photo-atomic interactions and self-shielding due to the NRF resonance itself. The change in energy spectrum and intensity due to the photo-atomic reactions has been quantified using the MCNP6 code and then the NRF self-shielding effect was considered to obtain the spectrums that include all the attenuation factors. Simulations show that when a $^{99}Tc$ target is irradiated at an intensity of the order $10^{17}{\gamma}/s$ for 30 h, 2.01 Ci of $^{99m}Tc$ can be produced.

• The Journal of the Korea Contents Association
• /
• v.18 no.12
• /
• pp.535-546
• /
• 2018

This study conducted a meta-analysis to examine syntagmatically on the variables related with recovery among persons with mental illness in Korea. In order to do a meta-analysis, theses and dissertations published between 1999 and 2018 in Korea were reviewed systematically and a total of 24 including studies were selected. Using Comprehensive Meta Analysis (CMA) 3.0 software, this study calculated average effect size and moderator variables related with recovery among persons with mental illness. Results were as follows. First, this study identified a total of 16 variables related with recovery among persons with mental illness. Second, the results indicated that variables which showed large effect sizes included social support(r=.575), empowerment(r=.555), self-efficacy(r=.544), social skill(r=.500), relationship with social worker(r=.482), stigma(r=-.446), family support(r=.418). Third, variables with medium effect sizes included interpersonal relationship capacity (r=.391), agency service satisfaction(r=.366), insight(r=.373) and symptom(r=-.239). Fourth, variables with small effect sizes included work experience(r=.188). Fifth, moderator analyses were conducted utilizing characteristics of residence state (community or mental hospital). Moderator effects were identified in the social support and family support. Based on the findings, theoretical and clinical implications for the recovery among persons with mental illness in Korea were discussed.

• Journal of Digital Contents Society
• /
• v.13 no.4
• /
• pp.501-516
• /
• 2012

The purpose of this study is to explore the fundamental nature and meanings of the experiences of university students with regard to their smartphone usage in order to prevent smartphone addiction and provide guidelines to develop effective interventions. Nine university students who were currently enrolled in an university located in a Korean province participated in this study. In-depth interviews were conducted from June of 2012 to July of 2012, and data were analyzed using Colaizzi's phenomenological qualitative method. As a results, five theme and 40 subthemes of experiences of problematic smartphone usage were identified. Those themes include 1) a desperate try to connect with others(exposing oneself without appropriate self-protection, seeking emotional comfort, hurt and mistrust); 2) excessive use of smartphone and loss of self-control(more smartphone usage over computer/over-immersion/excessive usage/habituation, loss of self-control); 3) psychological difficulties(excessive attachment and dependence, separation anxiety, clingingness, reduced patience) ; 4) threats to daily functioning (changes in priorities, regressed independent daily functioning, irregular daily patterns, health problems, interruptions from free messenger, academic difficulties); 5) potential for recovery(conflictual feelings and doubts over smartphone usage, importance of interpersonal(face-to-face) communications, willingness to cut down the use, hope for recovery). This study provided suggestions for the prevention effort against smartphone addiction.

• 대한공업교육학회지
• /
• v.37 no.1
• /
• pp.65-85
• /
• 2012

This study focuses on the 'invention technique and practical experience' unit to observe how the colleague mentoring class has its effect on self-efficacy. For this, we have selected experimental group and comparative group and proceeded the experiment. For five classroom hours of the 'technique of invention and practical experience' unit, each group was assigned different method to do the experiment. The experimental group was applied with the colleague mentoring method and the comparative group was applied with the self study method. To observe the differences of how it effects on one's self-efficacy, the questionnaire was distributed before and after class. Then, it was verified for the meaningful differences between the two groups. To summarize, the results are as follows. First, for self-efficacy experiment, the questionnaire before the experiment showed that there were no differences found between two groups. However, the questionnaire collected after the experiment showed great differences. The group with the colleague mentoring showed more meaningful differences at p<.05 significance level than comparative group. Furthermore, by observing the before and after questionnaire, it was found that both groups showed statistically meaningful differences at p<.05 significance level, but the experimental group showed greater self-efficacy improvements than comparative group. Second, when further examining the self-efficacy, the activity start expectation, activity continuation expectation, activity performance expectation, and experience recovery expectation showed the statistically meaningful differences at p<.05 significance level. According to the above results, it can be stated that the colleague mentoring class has more positive effects on the self-efficacy than self-study class. Summing up, the colleague mentoring class is more effective than self-study for fostering student's self-efficacy.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.416-421
• /
• 2005

Most of solar system dissemination has been focused on domestic hot water system of which utilization to a building is relatively simple and safe than solar heating system. Through the survey on a cause of solar house dissemination failure in Korea, we conclude that design integration and systematic approach method for technology application are the most important element for a successful solar house. KIER(Korea Institute of Energy Research) and Hanbat National University have started new project on a development of Zero energy Solar House, called ZeSH which can be sustained just by natural energy without the support of existing fossil fuel. This is the 1st phase research of 10 years long-term ZeSH plan which develops a low-cost and $100\%$ self sufficient ZeSH. The goal of 1st phase ZeSH research is to get a $70\%$ self sufficiency only in thermal loads. Actual demonstration house, named KIER ZeSH I was designed and constructed as a result of 1st phase research work in the end of 2002. Various innovative technologies such as super insulation, high performance window, passive and active solar systems, ventilation heat recovery system are applied and evaluated to the KIER ZeSH I. A lot of computer simulations had been conducted for the optimal design and system integration in every design steps. Considering all the results from detailed hourly computer simulation, it is expected that at least $70\%$ self-sufficiency in thermal loads which is 1st phase target value can be excessively achieved in actual demonstration house. Besides, many valuable findings from the design and analysis to construction could be established such as collaboration method among the participants, practical design and construction techniques for system integration and the others. The purpose of this paper is to introduce the main findings through the development of KIER ZeSH I project. Practical guidelines in every design step for new low- or zero- energy solar house is proposed as result.

• Journal of Korean Society of Rural Planning
• /
• v.20 no.2
• /
• pp.11-22
• /
• 2014

In this study, the objectives are to provide rural experience tourism village business courses and development direction in between individual farmers and the village in base on rural development business of Hapjeon-village. The developmental process of a farm-stay village can be categorized into the period of six stages: 1) a conception stage 2) an adoption stage 3) a growth stage 4) an expansion stage 5) a stagnation stage 6) a recovery stage. Farm Stay Villages, Individual Farmhouses or Producer Groups can be placed in four different quadrant areas of a graph, depending on the pursuing direction and results of core values by having the X-axis for economic factors (public profits, individual profits) and by having the Y-axis for emotional factors (self-actualization, conflicts). The first quadrant area is designated for ideal individual farmhouses and producer groups for having achieved the status of economic self-reliant and high emotional satisfaction. The second quadrant is for ideal self-actualized communal villages having achieved the independent public interest and public profitable status. The third quadrant is reserved for villages experiencing communal conflicts and no economic self-reliant stagnant status. The fourth guardant area is allocated for individual farmhouses and producer groups having achieved self-reliant economic status, yet having communal conflicts. Using the aforementioned concept, the government shall design village development projects and prepare realistic and achievable goals and place them in as a systematic device in future projects.

• The KIPS Transactions:PartC
• /
• v.12C no.7 s.103
• /
• pp.941-948
• /
• 2005

In the self-healing group key distribution scheme, users are capable of recovering lost group keys on their own without requesting additional transmission from the group manager, where there is no reliable network infrastructure. In this paper, we propose a new self-healing group key distribution scheme with revocation capability, which is optimal in terms of user memory storage and more efficient in terms of communication complexity than the previous results. We obtain a slightly improved result from (13) and (14) by using the new broadcasting method. In addition, we prove that our scheme has the properties of t-wise forward secrecy and t-wise backward secrecy, and extend this self-healing approach to the session key recovery scheme from a single broadcast message.

• The Research Journal of the Costume Culture
• /
• v.29 no.5
• /
• pp.719-734
• /
• 2021

The aim of this study was to determine the therapeutic effects of beauty care on negative mental health, including stress and depression. Nail care, massage care, and makeup were used as programs for beauty therapy. Qualitative research was conducted with six female participants over five-month period. After interviewing the subjects in advance, beauty care treatments were performed every week 4 weeks in the following order: nail care, massage, and makeup. The results are as follows, First, the participants perceived beauty care in the form of 4 concepts: "courtesy in social life," "investment in oneself," "self-satisfaction," and "self-care." Second, the effects of beauty therapy were categorized as "psychological effects," "confidence," "behavioral changes," "evaluation of others," and "positive social effects." Third, each subject showed different psychological effects during the process when the function of the therapy took effect through the beauty care treatment. It was confirmed that confidence levels increased as a result of treatment through the process of becoming re-aware of oneself. Positive statements from the participants included: "I want to go out," "I have become kind and positive to others," "I have become more active in a given task," and "It seems that my work ability is improving." Finally, t-test results for self-esteem, depression, and stress showed there were significant differences in self-esteem and depression. This confirmed that self-esteem increased, and depression decreased after the beauty care treatment.

• Asia-Pacific Journal of Business
• /
• v.12 no.1
• /
• pp.151-163
• /
• 2021

Purpose - The break-even point refers to the point where total profit and total cost coincide, and from this point on, the entrepreneur's decision-making takes a different route. Strategic decisions can be made for more efficient operation and eventually for more likelihood for growth and sustainability if a startup figures out when it recoups the investment and switches to a net profit. Design/methodology/approach - 748 creativity and skill-based sole proprietors in manufacturing industry were examined to demonstrate the effect of the entrepreneur's entrepreneurial experience and education level, the business launch preparation time, or the self-financing on the achievement of break-even point. Findings - While the business launch preparation time lowered the likelihood of reaching a break-even point, self-financing increased the likelihood. As a result of further analysis by subdividing into subgroups according to skill level, only the business launch preparation time was statistically significant in the highly skilled industries. In the low skilled industries, in addition to the business launch preparation time, the CEO's education level and the self-financing were statistically significant. Research implications or Originality - The longer the business launch preparation time, the higher the start-up cost, which increases the burden of initial cost recovery, and the agile response to market changes is thereby delayed, resulting in the business idea losing its appeal. Self-financing not only provides stability and strong motivation for the business operation but also promotes careful spending which contributes to the achievement of break-even point. In particular, it is found that practical experience is more useful than theoretical knowledge in low skilled industries. Due to the limitation of secondary data based on the recollection, the time required to reach a break-even point, percentage of financing sources, etc. may include cognitive errors. In addition, variables are not included that explain the characteristics of creativity and skill-based sole proprietorship, so it is necessary to exercise caution with the actual application.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.4
• /
• pp.600-608
• /
• 2022

This study investigates the effect of layered double hydroxide (LDH) on the healing performance of self-healing concrete by assessing the chloride penetration resistance of self-healing cement mortars using electrical chloride ion migration-diffusion test. Test results show that both mortars containing healing materials only and mortars containing healing materials and Ca-Al LDH together mostly had higher migration-diffusion coefficients right after cracking, but the migration-diffusion coefficients decreased more than that of OPC with increasing healing ages, and thus, they yielded higher healing capacities than OPC. Also, mortars containing Ca-Al LDH together with healing materials showed higher reduction of their migration-diffusion coefficients, and thus, higher healing capacities than mortars containing healing materials only. This suggests that as the self-healing product increases on the crack surface, the binding of chloride ions by LDH inside the crack increases.