• Radiation Oncology Journal
• /
• v.16 no.1
• /
• pp.71-79
• /
• 1998

Purpose : The objective of this study is to introduce our installation of a non-commercial 3D Planning system, Plunc and confirm it's clinical applicability in various treatment situations. Materials and Methods : We obtained source codes of Plunc, offered by University of North Carolina and installed them on a Pentium Pro 200MHz (128MB RAM, Millenium VGA) with Linux operating system. To examine accuracy of dose distributions calculated by Plunc, we input beam data of 6MV Photon of our linear accelerator(Siemens MXE 6740) including tissue-maximum ratio, scatter-maximum ratio, attenuation coefficients and shapes of wedge filters. After then, we compared values of dose distributions(Percent depth dose; PDD, dose profiles with and without wedge filters, oblique incident beam, and dose distributions under air-gap) calculated by Plunc with measured values. Results : Plunc operated in almost real time except spending about 10 seconds in full volume dose distribution and dose-volume histogram(DVH) on the PC described above. As compared with measurements for irradiations of 90-cm 550 and 10-cm depth isocenter, the PDD curves calculated by Plunc did not exceed $1\%$ of inaccuracies except buildup region. For dose profiles with and without wedge filter, the calculated ones are accurate within $2\%$ except low-dose region outside irradiations where Plunc showed $5\%$ of dose reduction. For the oblique incident beam, it showed a good agreement except low dose region below $30\%$ of isocenter dose. In the case of dose distribution under air-gap, there was $5\%$ errors of the central-axis dose. Conclusion : By comparing photon dose calculations using the Plunc with measurements, we confirmed that Plunc showed acceptable accuracies about $2-5\%$ in typical treatment situations which was comparable to commercial planning systems using correction-based a1gorithms. Plunc does not have a function for electron beam planning up to the present. However, it is possible to implement electron dose calculation modules or more accurate photon dose calculation into the Plunc system. Plunc is shown to be useful to clear many limitations of 2D planning systems in clinics where a commercial 3D planning system is not available.

• Korean Journal of Ecology and Environment
• /
• v.48 no.2
• /
• pp.108-114
• /
• 2015

Single - and combined effects of a domestic freshwater bivalve Unio douglasiae (7.6~8.6 cm in shell length) and zooplankton Daphnia magna (1~2 mm in body size) were examined to understand whether they inhibit the growth of harmful cyanobacterial bloom (i.e. Microcystis aeruginosa) in a eutrophic lake. The experiments were triplicated with twelve glass aquaria (40 L in volume); three aquaria without mussel and zooplankton, served as a control, three zooplankton aquaria (Z, density=40 indiv. $L^{-1}$), three mussel aquaria (M, density=0.5 indiv. $L^{-1}$), and three mussel plus zooplankton aquarium (ZM, density=40 indiv.Z $L^{-1}$ plus 0.5 indiv.M/L), respectively. Algal growth inhibition (%) calculated as a difference in the concentration of chlorophyll-a (Chl-a) before and after treatment. Chl-a in all aquaria decreased with the time, while a greatest algal inhibition was seen in the ZM aquaria. After 24 hrs of incubation, Chl-a concentration at the mid-depth (ca. 15 cm) in ZM aquaria reduced by 90.8% of the control, while 63.2% and 79.8% in Z and M aquaria, respectively. Interestingly, during the same period, the surface Chl-a was diminished by 51.9% and 65.4% relative to the control in Z and ZM aquaria, while 27.4% of initial concentration decreased in M aquarium, respectively. These results suggest that 1) this domestic freshwater filter-feeding bivalve plays a significant role in the control of cyanobacterial bloom (M. aeruginosa), and 2) the combination with zooplankton and mussel has a synergistic effect to diminish them, compared to the single treatment of zooplankton and mussel.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.23 no.4
• /
• pp.247-254
• /
• 2003

A study was carried to compare two varieties of tall fescue(Festuca arundinacea Schr.): Fawn (endophyte infection) and Roa(endophyte-free). The study examined plant height, botanical composition, and dry matter yield of mixed pasture. The cattle grazed on a mixed pasture of tall fescue species and orchardgrass(Dactylis glomerata L.), perennial ryegrass(Lolium perenne L.) and white clover(Trifolium repens L.) during March 22, 1997, to September 21, 1997. The number of grazing animals was 4.3/ paddock(50m x50m) and was adjusted according to the condition of pasture. Dry matter yields determined on ungrazed pasture(7-time harvests) were 1,690 $\pm$407kg and 1,128 $\pm$ 238kg/ha on pastures consisting of Fawn and Roa, respectively. This difference was significant(P<0.01). There were 17.71 $\pm$ 1.27cm and 12.83$\pm$0.90cm in average plant lengths of Fawn and Roa(P<0.01), respectively The botanical composition of tall fescue and orchardgrass in the mixture treatment included in the Fawn variety were shown in 34.2 and 3.8％, comparing Roa with 17.1 and 9.6％, on the 21th of September, 1997, respectively. Tall fescue Roa represented a higher botanical composition than orchardgrass(a main species on Cheju). Crude protein content of Fawn was slightly less than that of Roa. From these results, we may conclude that Roa variety is nutritionally better, but is less adaptible to high temperature climate than Fawn. However, Roa variety is still better than orchardgrass in high temperature conditions.

• Journal of Food Hygiene and Safety
• /
• v.30 no.3
• /
• pp.217-226
• /
• 2015

This study was conducted to establish a standardized process for developing food safety health indicators. With this aim, we proposed a standardized process, accessed the validity of the suggested process by performing simulations, and provided a method to utilize the indicators. Developing process for domestic environmental health indicators was benchmarked to propose a standardized process for developing food safety health indicators, and DPSEEA framework was applied to the development of indicators. The suggested standardized process consists of an exploitation stage and a management stage. In the exploitation stage, a total of 6 procedures (initial indicators suggestion, candidate indicators selection, data availability assessment, feasibility assessment, pilot study, and final indicator selection) are conducted, and the indicators are routinely calculated and officially announced in the management stage. The exploitation stage is operated by an interaction between a task force team who manages the overall process, and an advisory committee (minimum of 4 in academia, 2 in research, 4 in specialists of Ministry of Food and Drug Safety) who reviews and performs evaluations on the indicators. The standardized process was simulated with 45 initial indicators, and total of 4 indicators (17 detailed indicators) were selected: 'Proportion of domestic fruit/vegetable receiving 'acceptable' in the evaluation of pesticide/herbicide residues', 'Food-borne disease outbreaks', 'Food-borne legal infectious disease incidence', 'Salmonellosis incidence'. Synthetic food safety health index was derived by calculating percent difference with the data from 2010 to 2012. Results showed that when comparing the year 2010 to 2011, and 2011 to 2012, the overall food safety status improved by 10.37% and 9.87%, respectively. In addition, the contribution of indicators to the overall food safety status can be determined by looking into the individual indicators, and the synthetic index may be illustrated to enhance the ease of interpretation to the public and policy makers. In overall, food health safety indicators can be useful in many ways and therefore, attention should be drawn to conduct further studies and establish related legislations.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.4
• /
• pp.962-973
• /
• 2017

Concerns about an air pollution are gradually increasing at home and abroad. The automotive and fuel researchers are trying to reduce emissions and greenhouse gases of vehicles through a research on new engine designs and innovative after-treatment systems using clean fuels (eco-alternative fuel) and fuel quality improvements. In this paper, we stduy the emission characteristics of greenhouse gases on seven vehicles using gasoline, diesel, and LPG by legal test mode in domestic and abroad.(Urban mode, Highway mode, rapidly acceleration and deceleration, using air conditioner, low temperature condition) Regardless of fuels, most of the greenhouse gases tend to show the worst results in cold FTP-75 mode. In the case of A vehicles (2.0 MPI) and B vehicles (2.4 GDI) using a gasoline fuel, the factors that increase greenhouse gases are in order of a rapidly acceleration and deceleration, using air conditioner, low temperature condition. But G vehicles(LPLi) have different emission characteristics from another vehicles. In the case of A vehicles (2.0 w/o DPF) and B vehicles (2.2 with DPF) using a diesel fuel, the factors that increase greenhouse gases are in order of a rapidly acceleration and deceleration, using air conditioner, low temperature condition. However, the factor of F vehicles are in order of low temperature condition, using air conditioner, rapidly acceleration and deceleration. In conclusion, it will be an effective method to apply different technologies of emission reduction for each fuel.

• The Korean Journal of Emergency Medical Services
• /
• v.18 no.1
• /
• pp.83-94
• /
• 2014

Purpose : This study assessed the improvement of competency levels for participants, as well as their satisfaction from completion of the special international disaster response program. Methods : The program structure followed an intensive two-week course that included a combination of lectures, discussions, case studies, and field trips. "ICN Framework of Disaster Nursing Competencies" was used for designing the program. A pre-post survey was done to measure the change in the competencies of students and assess their satisfaction after finishing the program. Focus group interviews were also performed to further understand the attitudes of participants toward the disaster issues. Results : The overall pre-program test score for disaster competency was $2.18{\pm}0.68$ and the post-program test score was $6.30{\pm}0.84$, which showed statistically significant gains in all competency items (p <.001). The general satisfaction of participants with the program was quite high, demonstrated by a mean score of $4.5{\pm}0.51$. The benefits for students from program participation included increased knowledge and better understanding of the important roles of international organizations and NGOs. Conclusion : The international disaster education programs are necessary to provide an opportunity for students to increase their disaster competency. In addition, future development of a unified educational competency framework is also necessary.

• Korean Journal of Social Welfare Studies
• /
• v.49 no.3
• /
• pp.5-33
• /
• 2018

A self-sufficiency service has worked as a typical workfare policy combined with public assistance in Korea since 2000. Despite of its long history, three core pillars in administrating the self-sufficiency service, policy, research, and practice, have respectively understood the meaning of self-sufficiency in terms of their own interests. As a result, the self-sufficiency service has recently faced with its own identity issues by showing failures to its environmental changes. The current situation makes it necessary to reconceptualize the definition of self-sufficiency by exploring its in-depth understanding perceived by service providers. Specifically, we analyzed practical reflections on 35 service providers' experiences which were collected via focus group interviews for two hours. The study findings presented that service providers had two antithetical approaches towards self-sufficiency. While a dominant approach to self-sufficiency has been concentrated on improving clients' economic outcomes such as employment, job retention, the escape from welfare trap, and increasing earnings and assets, the other approach has been extended to empower clients and achieve their well-being and quality of life. Yet, these contrary perspectives have led to suffer from their role confusions and identity crisis between the work-ready process and the employment-oriented outcomes. Specifically, they described self-sufficiency in terms of psychological, social, and integrated aspects. The psychological aspect included a process of developing inner strengths, intensifying job motivation, and coping with barriers of employment. The social aspect meant a path toward social integration through recovering human relationships. The integrated aspect covered more comprehensive support for their recovery of daily life and autonomy to make a decision for their own life. In conclusion, the study findings suggest that self-sufficiency should be more extensively considered as a stepwise process towards work-ready preparations beyond ultimate economic outcomes. Such an extended concept of self-sufficiency could contribute to restructuring the whole practice of self-sufficiency including organizational and program changes in the fields.

• Elastomers and Composites
• /
• v.45 no.4
• /
• pp.263-271
• /
• 2010

Intermittent CSR testing was used to investigate the degradation of an FKM O-ring, also the prediction of its life-time. An intermittent CSR jig was designed taking into consideration the O-ring's environment under use. The testing allowed observation of the effects of friction, heat loss, and stress relaxation by the Mullins effect. Degradation of O-rings by thermal aging was observed between 60 and $160^{\circ}C$. In the high temperature of range ($100-160^{\circ}C$) O-rings showed linear degradation behavior and satisfied the Arrhenius relationship. The activation energy was about 60.2 kJ/mol. From Arrhenius plots, predicted life-times were 43.3 years and 69.9 years for 50% and 40% failure conditions, respectively. Based on TTS (time-temperature superposition) principle, degradation was observed at $60^{\circ}C$, and could save testing time. Between 60 and $100^{\circ}C$ the activation energy decreased to 48.3 kJ/mol. WLF(William-Landel-Ferry) plot confirmed that O-rings show non-linear degradation behavior under $80^{\circ}C$. The life-time of O-rings predicted by TTS principle was 19.1 years and 25.2 years for each failure condition. The life-time predicted by TTS principle is more conservative than that from the Arrhenius relationship.

• Food Science and Preservation
• /
• v.19 no.6
• /
• pp.799-806
• /
• 2012

This experiment was conducted to establish the optimum conditions for high $CO_2$ gas treatment in combination with a proper gas-permeable packaging film to maintain the quality of fig fruit (Ficus carica L). Among the fig fruits with different high $CO_2$ treatments, the quality change was most effectively controlled during storage in the 70%-$CO_2$-treated fig fruit. Harvested fig fruit was packaged using microperforated oriented polypropylene (MP) film to maintain the optimum gas concentrations in the headspace of packaging for the modified-atmosphere system. MP film had an oxygen transmission rate of about $10,295cm^3/m^2$/day/atm at $25^{\circ}C$. The weight loss, firmness, soluble-solid content (SSC), acidity (pH), skin color (Hunter L, a, b), and decay ratio of the fig fruits were monitored during storage at 5 and $25^{\circ}C$. The results of this study showed that the OPP film, OPP film + 70% $CO_2$, and MP film+70% $CO_2$ were highly effective in reducing the loss rate, firmness and decay occurrence rate of fig fruits that were packaged with them during storage. In the case of using treatments with packages of OPP film and OPP film+70% $CO_2$, however, adverse effects like package bursting or physiological injury of the fig may occur due to the gas pressure or long exposure to $CO_2$. Therefore, the results indicated that MP film containing 70% $CO_2$ can be used as an effective treatment to extend the freshness of fig fruits for storage at a proper low temperature.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.16 no.4
• /
• pp.85-99
• /
• 2021

Due to the continuous unemployment problem, the number of jobs is gradually decreasing, and entrepreneurship is emerging as an alternative. This is because, despite the government operating various start-up support programs to build a start-up-friendly culture, young entrepreneurs cannot endure the valley of death and disappear. Therefore, through this study, we intend to provide implications by analyzing the impact on Entrepreneurial satisfaction, which is essential for continuously running a business, and life satisfaction, which can act as a social awareness. This study was conducted with 573 non-wage workers who belonged to the founders among the participants of the 'College Graduation Occupational Migration Path Survey(GOMS)' survey provided by the Korea Employment Information Service. In order to analyze the relationship between entrepreneurial competency and job fit, Entrepreneurial satisfaction, and life satisfaction, the analysis was conducted using the SPSS 23.0 program. The main research results are summarized as follows. First, entrepreneurial competency has a positive effect on Entrepreneurial satisfaction and life satisfaction. Second, job fit indicates a moderating role in the relationship between entrepreneurial competency and Entrepreneurial satisfaction. Third, start-up satisfaction appears to have a partial mediating role in the relationship between entrepreneurial competency and life satisfaction. Fourth, as a result of analyzing the difference between groups according to the type of start-up(single/partnership), the group that worked together showed higher Entrepreneurial satisfaction and life satisfaction. The main implications of this study are: First, in order to increase the Entrepreneurial satisfaction and life satisfaction of university graduates who are the subject of the study, it will be necessary to design a program that can diagnose and enhance the entrepreneurial competency of students at the university level. Second, entrepreneurial competency is a basic intrinsic factor that founders must have, and it should act as an important evaluation factor when selecting founders for support programs from start-up support organizations as well as founders. Third, it is necessary to maintain mutual trust by documenting problems (positions, wages, management rights, distribution of profits, etc.) that may occur in joint ventures with objective data. Fourth, it is necessary to establish an environment in which the MZ generation, armed with the challenging spirit and creativity, can continue to take on challenges even if they fail.