• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.145-149
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• 2013

Helical Tomotherapy is an innovative means of delivering intensity modulated radiation therapy (IMRT) using a device that merges features of a linear accelerator and helical computed tomography (CT) scanner. Hereat, during helical tomotherapy process, megavoltage computed tomography (MVCT) image are usually used for guiding the precise set-up of patient before/after treatment delivery. But which would certainly increase the total dose for patients, this study was to investigate the imaging dose of MVCT using the cylindrical "Cheese" phantom on a tomotherapy machine. A set of cylindrical "Cheese" phantom was adopted for scanning with respectively pitch value (1, 2, 3 mm) with same number slice (10 slice), same length (approximately 9 cm) and phantom set-ups on the couch of tomotherapy system. The average MVCT imaging dose were measured using A1SL ion chamber inserted in the phantom with preset geometry. The MVCT scanning average dose for the cylindrical "Cheese" phantom was 2.24 cGy, 1.02 cGy, 0.81 cGy during respectively pitch value (pitch 1, 2, 3 mm) with same number slice (10 slice), and same length's average dose was 2.47 cGy, 1.28 cGy, 0.88 cGy respectively (pitch 1, 2, 3 mm). Two major parameters, the assigned pitch numbers and scanning length, where the most important impacts to the dose variation. The MVCT dose was inversely proportional to the CT pitch value. The results may provide a reliable guidance for proper planning design of the scanning region, which is valuable to help minimize the extra dose to patient. Questionnaires were distributed to Radiology departments at hospitals with 300 sickbeds throughout the Pohang region of North Gyeongsang Province concerning awareness and performance levels of infection control. The investigation included measurements of the pollution levels of imaging equipment and assistive apparatuses in order to prepare a plan for the activation of prevention and management of hospital infections. The survey was designed to question respondents in regards to personal data, infection management prevention education, and infection management guidelines.

• Environmental and Resource Economics Review
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• v.23 no.4
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• pp.719-746
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• 2014

This study attempts to estimate the value of the water quality improvement by deriving the equilibrium price of the water pollutant emission permit for the imaginary water pollutant emission trading market. It is reasonable to say that there is already an implicit social agreement for the unit value of water pollutant, when the government set the Total Water Pollutant Loading System for the major river basin as a part of the Comprehensive Measures for Water Management, particularly for the Nakdong River Basin. Therefore, we can derive the unit value of water pollutant emission, which is already implied in the pollution allowance for each city or county by the Total Water Pollutant Loading System. Once estimated, it will be useful to the economic assessment of the water quality related projects. An imaginary water pollutant emission trading system for the Nakdong River Basin, where Total Water Pollutant Loading System is already effective, is constructed for the estimation of the equilibrium price of water pollutant permit. By estimating marginal abatement cost curve or each city or county, we can compute the equilibrium price of the permit and then it is regarded as the economic value of the water pollutant. The marginal net benefit function results from the relationship between the emission and the benefit, and then the equilibrium price of permit comes from constructing the excess demand function of the permit by using the total allowable permit of the local government entity. The equilibrium price of the permit would be estimated to be $1,409.3won/kg{\cdot}BOD$. This is within reasonable boundary compared for the permit price compared to foreign example. This permit price would be applied to calculate for the economic value of the water quality pollutants, and also be expected to use directly for the B/C analysis of the business involved with water quality change.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.817-838
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• 2005

In this paper, the resource adequacy as well as the optimum fuel mix is obtained by the following procedures. First, the regulation body, the government agency, determine the reliability index as well as the optimum portfolio of the fuel mix during the planning horizon. Here, the resources with the characteristics of public goods such as demand-side management, renewable resources are assigned in advance. Also, the optimum portfolio is determined by reflecting the economics, environmental characteristics, public acceptance, regional supply and demand, etc. Second, the government announces the required amount of each fuel-type new resources during the planning horizon and the market participants bid to the government based on their own estimated fixed cost. Here, the government announces the winners of the each auction by plant type and the guaranteed fixed cost is determined by the marginal auction price by plant type. Third, the energy market is run and the surplus of each plant except their cost (guaranteed fixed cost and operating cost) is withdrew by the regulatory body. Here, to induce the generators to reduce their operating cost some incentives for each generator is given based on their performance. The performance is determined by the mechanism of the performance-based regulation (PBR). Here the free-riding performance should be subtracted to guarantee the transparent competition. Although the suggested mechanism looks like very regulated one, it provides two mechanism of the competition. That is, one is in the resource construction auction and the other is in the energy spot market. Also the advantages of the proposed method are it guarantee the proper resource adequacy as well as the desired fuel mix. However, this mechanism should be sustained during the transient period of the deregulation only. Therefore, generation resource planning procedure and market mechanisms are suggested to minimize possible stranded costs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.446-455
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• 2018

This study examined the effects of different performance sequences of aerobic and strength exercises for 10 weeks on the body composition, physical function, and hormones in males aged in their 20s. A total of 30 subjects (N=30) were assigned randomly to either aerobic and resistance exercise (n=10, A+R), resistance and aerobic exercise (n=10, R+A), or a control group (n=10, CON). The different order of aerobic (HRmax 50-80%, 30 min) and resistance (50-80% 1RM, 30 min) exercises for 10 weeks was consisted of 3 times per week and 80 minutes per session. The body composition, physical function, and hormones were measured before and after the training period. The lean body mass (p=.015) was increased and the fat mass (p=.042) and % body fat (p=.007) in the A+R were decreased. The skeletal muscle mass (p=.001) in the R+A was increased and % body fat was decreased (p=.003). The weight (p=.03) and % body fat (p=.039) in the CON were increased. The aerobic capacity (p=.011) and muscular endurance (p=.001) in the A+R group were improved. The muscular endurance (p=.0016) in the R+A was improved. The epinephrine (p=.048), norepinephrine (p=.013), and cortisol (p=.045) levels in the A+R group were increased. The epinephrine (p=.046) level in the R+A group was increased. The insulin (p=.007) level increased in the CON group. In conclusion, both A+R and R+A groups produced superior results to the CON group but the A+R group was slightly more efficient than the R+A group.

• Journal of Nutrition and Health
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• v.49 no.5
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• pp.378-394
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• 2016

Purpose: Screening of preschool-age children for nutrition programs to improve dietary intake and behaviors requires cost-effective and easily administered validated assessment tools. The purpose of this study was to develop a parent/caregiver-administered instrument for measuring diet quality and behaviors of preschoolers as a nutrition quotient for preschoolers (NQ-P). Methods: Development of NQ-P was carried out in three steps: item generation, item reduction, and validation. The 24-h dietary record was selected as the gold standard reference tool. The 38 items of the NQ-P checklist were derived from a systematic literature review, expert in-depth interviews, statistical analysis of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. Self-administered questionnaires were delivered to parents who recorded 24-h dietary intakes of 100 responders aged 3~5 yr. Pearson's correlation was used to measure the level of agreement between questionnaires. Item reduction was performed, and 20 items were selected based on survey results, expert reviews, and priorities of national nutrition policy and recommendations. The 412 nationwide subjects sampled through daycare centers completed the 20-item checklist questionnaire. The construct validity of the NQ-P was assessed using confirmatory factor analysis, LISREL. Results: After analyses of exploratory factors, NQ-P items identified three dimensions of diet (balance, moderation, and environment). The three-factor structure accounted for 49.28% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-P and three-factor scores of the subjects were calculated by the obtained weights of the questionnaire items. Conclusion: A food behavior checklist for preschoolers' NQ would be a useful and suitable instrument for evaluating nutrition adequacy and dietary quality of Korean preschoolers.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Journal of Preventive Medicine and Public Health
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• v.34 no.2
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• pp.127-130
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• 2001

Objective : To verify the separate and combined effects of cadmium and nickel on blood pressure in rats. Methods : Following the daily administration of cadmium chloride$(CdCl_2)$ and nickel chloride$(NiCl_2)$ to rats both individually and in combination with intraperitoneal injection method for one week, systolic blood pressure of the tail was measured at 1 day and 5, 10, 20, 30 days after administration. Each substance was injected into the rats with 0.1 mg/kg bw and 1.0 mg/kg bw concentration. Results : After 0.1 mg/kg bw $CdCl_2$ was injected, a statistically significant difference was found as compared with the control group(only saline) after 1, 5 and 10 days. After 0.1 mg/kg bw $NiCl_2$ was injected, a statistically significant difference was not found compared with the control group. After 0.1 mg/kg bw $CdCl_2$ and 0.1 mg/kg bw $NiCl_2$ were injected simultaneously, a statistically significant difference was found as compared with the control group after 1,5 and 10 days and compared with 0.1 mg/kg bw $CdCl_2$ group after 5 days and as compared with 0.1 mg/kg bw $NiCl_2$ group after 5 and 10 days. After 1.0 mg/kg bw $CdCl_2$ was injected, a statistically significant difference was found as compared with the control group after 1, 5, 10 and 20 days. After 1.0 mg/kg bw $NiCl_2$ was injected, a statistically significant difference was found as compared with the control group after 1 day and 5 days. After 1.0 mg/kg bw $CdCl_2$ and 1.0 mg/kg bw $NiCl_2$ were injected in combination, a statistically significant difference was found after 1, 5, 10, 20 and 30 days as compared with 1.0 mg/kg bw $CdCl_2$ after 10, 20 and 30 days and as compared with 1.0 mg/kg bw $NiCl_2$ after 5, 10, 20 and 30 days. Conclusion : It was found that the effect of $CdCl_2$ on blood pressure was much more than $NiCl_2$ and a high concentration $CdCl_2\;and\;NiCl_2$ in combination delayed the recovery of blood pressure.

• Korean Security Journal
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• no.11
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• pp.21-36
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• 2006

This study aims to grasp the general conditions regarding university students in security related majors in Korea. Followings will be covered here: what motivated them to choose those majors, how much are they satisfied with major curriculum course after matriculation, whether they got jobs through the education, what is their consciousness on their majors, jobs, and courses like, and what effects their job preference. And this study also aims at helping the students with their future plans such as admission to a school of higher grade and choosing their job. For this study, we distributed 340 cpoies to the students in security related majors at 4 four-year colleges and 1 two-year college, and collected 298 copies by means of quota sampling method. For collected questionnaires, we used individual T-test verification and one-way ANOVA analysis to grasp the situation. Significance standard for the test results was set as p<0.05. Following are the test results. First, the analysis on students' satisfaction rate resulted in male students' average of 2.42, compared to female students' average of 2.10, which shows female students have higher satisfaction rate in choosing their majors than male students. Secondly, The results on analysis of satisfaction rate on their curriculums, classes, and majors show that students in security-related majors showed different satisfaction rate and different averages according to their sex and the year of the college. The study indicates that males have higher satisfaction rate on curriculum than females, with male students' average of 2.63 and female students' average 2.88. According to the year of the college, there was a significant difference statistically, Statistics show that students at two-year college have higher satisfaction rate than those at four-year college, with two-year college students' average of 2.48 and four-year college students' of 2.74. students have the average of 3.56. The higher year they were in, the more improvement the curriculum required. When it comes to convenience offer for employment, male students expected more from school than female students, with males' average of 2.74 and females' average of 4.07. Male students marked higher than female students in the extent of job information offer, with males' average of 2.96 and females' average of 2.59. Fourthly, when students in security-related majors were surveyed on their consciousness of their future plans such as getting jibs, two-year college students had more certificates of qualification for employment than four-year college students. What they do preponderantly in preparation for employment was studying foreign languages, which took up 40.4%. And when they were asked on their confidence for employment, positive answers were far more than negative ones with the percentage of 39.6%, while negative took up just 14.0%. Fifthly, when it come to the students in security-related students' job preferences, 49.2% preferred safe job conditions in public security area and 34% preferred private guard or private security organizations. And in the public security area, the highest percentage of 28.6 preferred to work in presidential security service. In the area of private security, 21.2% showed interests in private guard and private security organizations.

• Korean Journal of Social Welfare
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• v.57 no.3
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• pp.305-335
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• 2005

This paper is a result from validation study for SPDA(A Screening Scale For Potential Drug-use Adolescents) created in 2003 and newly developed during 2004. SPDA aims to screen adolescents in their early stage of drug-use and to help practitioners make a preventive approach for the adolescents. 4307 junior and senior high school students were selected as primary research subjects by stratified and quota sampling methods. 305 adolescents on probation were also selected as a comparison group and asked to answer the same questionnaire. Reliability for SPDA recorded 0.914, which proved to be better than previous year's (0.898). Exploratory and confirmatory factor analyses to test construct validity proved that SPDA could be divided into 7 factors and that each factor structure of SPDA could be a proper measurement model with high level of fitness and factor loadings. Discriminant analysis to test predictive validity confirmed that SPDA could classify the adolescents excellently by the frequency of drug-use, with hit ratio of 86.6 percent(78.8% and 87.4% for junior and senior high school students respectively). For concurrent validity test, Hare Home Self-Esteem Scale, Hare School Self-Esteem, Zuckerman-Kuhlman Sensation-seeking Scale were employed to find correlation with SPDA and all the three scales had significant Pearson correlation coefficients with SPDA. Known-groups validity test indicated that SPDA had an adequate power to classify out adolescents on probation from those in schooling, with a hit ratio of 71.8 percent. Cut-off point to detect adolescents with high risk of substance use was 77, which indicated approximately T score, 55 (0.5 SD), satisfying sensitivity, specificity, and efficiency criteria.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.108-116
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• 2009

In this paper, we propose a Ethernet based audio distribution system with a new L1/L2 hybrid switching scheme, and evaluate its performance. The proposed scheme not only offers guaranteed low latency and jitter characteristics that are essentially required for the distribution of high-quality uncompressed audio traffic, and but also provide an efficient transmission of data traffic on the Ethernet environment. The audio distribution system with a proposed scheme consists of a master node and a number of relay nodes, and all nodes are mutually connected as a daisy-chain topology through up and downlinks. The master node generates an audio frame for each cycle of 125us, and the audio frame has 24 time slotted audio channels for carrying stereo 24 channels of 16-bit PCM sampled audio. On receiving the audio frame from its upstream node via the downlink, each intermediate node inserts its audio traffic to the reserved time slot for itself, then relays again to next node through its physical layer(L1) transmission - repeating. After reaching the end node, the audio frame is loopbacked through the uplink. On repeating through the uplink, each node makes a copy of audio slot that node has to receive, then play the audio. When the audio transmission is completed, each node works as a normal L2 switch, thus data frames are switched during the remaining period. For supporting this L1/L2 hybrid switching capability, we insert a glue logic for parsing and multiplexing audio and data frames at MII(Media Independent Interlace) between the physical and data link layers. The proposed scheme can provide a good delay performance and transmission efficiency than legacy Ethernet based audio distribution systems. For verifying the feasibility of the proposed L1/L2 hybrid switching scheme, we use OMNeT++ as a simulation tool with various parameters. From the simulation results, one can find that the proposed scheme can provides outstanding characteristics in terms of both jitter characteristic for audio traffic and transmission efficiency of data traffics.