• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.136-147
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• 2004

In this study, the characteristics of magnetotelluric (MT) responses due to a three-dimensional (3-D) body are analyzed with 3-D numerical modeling. The first model for the analysis consists of a single isolated conductive body embedded in a resistive homogeneous half-space. The second model has an additional conductive overburden while the other conditions remain the same as the first one. The analysis of apparent resistivities shows well that the 3-D effects are dominant over some frequency range for the first model. Two mechanisms, current channeling and induction, for secondary electric fields due to the conductive body are analyzed at various frequencies: at high frequencies induction is more dominant than channeling, while at low frequencies channeling is more dominant than induction. Tippers have a strong relation to the position of anomalous body and the real and imaginary parts of induction vector also indicate the position of anomalous body. off-line conductive anomaly sometimes causes severe problem in 2-D interpretation. In such case, induction vector analysis can give information on the existence and location of the anomalous body. Each parameter of the second model shows similar responses as those of the first model. The only difference is that the magnitude of all parameters is decreased and that the domain showing the 3-D effects becomes narrower. As shown in this study, the analysis of 3-D effects provides a useful and effective means to understand the 3-D subsurface structure and to interpret MT survey data.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.94-98
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• 2006

An optical microphone based on a dual-core fiber collimator and a membrane type micromirror serving as an optical head and a reflective diaphragm respectively was implemented. The micromirror diaphragm is suspended by a thin silicon bar linked with a frame, thus it is subject to a displacement induced by acoustic waves. The optical head incorporating two collimators integrated in a single housing gives light to and receives it from the diaphragm, rendering the optical microphone structure simple and compact. This dual-core collimator having a slowing varying beam profile facilitates the initial alignment of the optical head with the diaphragm, especially the distance between them. For the assembled microphone, the static characteristics were investigated tofind the operation point defined as the optimum distance between the head and the diaphragm, and a frequency response with a variation of about $\pm$5 dB for the range of up to 3kHz was achieved.

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.281-289
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• 2017

In the present research, the optical measurement error induced by vibration of the optical measurement tower for large mirrors at KRISS (Korea Research Institute of Standards and Science) is investigated. The vibrations of the tower structure, the interferometer, and the null lens are measured while the surface errors of the 600-mm-diameter on-axis aspheric mirror are measuring, under various environmental conditions. The increase of surface error induced by alignment error with respect to vibration is analyzed. As a result, the interferometer and the null lens, which are located on the top of the tower, are highly sensitive to vibration. Additionally, the surface error of the mirror is strongly increased when the vibration directions of the interferometer and the null lens are different. To reduce the alignment error and the surface error induced by vibration, the tower structure should be improved, to be insensitive to low-frequency vibration. Alternatively, optical measuring under stable conditions by vibration monitoring can improve the reliability of the surface error measurement.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.299-299
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• 2017

Due to the climate changes in Korea, the numbers of both torrential rain events and drought periods have increased in frequency. Water management practice against water shortage and flooding is one of the key interesting for field crop cultivation, and groundwater often serves as an important and safe source of water to crops. Therefore, the objective of this study is to evaluate the effect of groundwater table levels on soil water content and soybean development under two different textured soils. The experiment was conducted using lysimeter located in Miryang, Korea. Two types of soils (sandy-loam and silty-loam) were used with three groundwater table levels (0.2, 0.4, 0.6m). Mean soil water content during the soybean growth period was significantly influenced by groundwater table levels. With the continuous groundwater level at 0.2m from the soil surface, soil water content was not statistically changed between vegetative and reproductive stage, but the 0.4 and 0.6m groundwater table level was significantly decreased. Lower chlorophyll content in soybean leaves was found in shallow water table treatment in earlier part of the growing season, but the chlorophyll contents were non-significant among water table treatments. Groundwater table level treatments were significantly influenced on plant available nitrogen content in surface soil. The highest N contents were observed in 0.6m groundwater table level. It is probably due to the nitrogen loss by denitrification as the result of high soil water content. The length and dry weight of primary root was influenced by groundwater level and thus the highest length and dry weight of root were observed in 0.6m water table level. This result showed that soybean root growth did not extend below the groundwater level and increased with the depth of groundwater table level. The results of this study show that the management of groundwater level can influence on soil characteristics, especially on soil water content, and it is an important practice of to reduce yield loss caused by the water stress during the crop growing season.

• Journal of Internet Computing and Services
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• v.14 no.4
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• pp.25-33
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• 2013

The procedure of the arbitration which is the tag collision is essential because the multiple tags response simultaneously in the same frequency to the request of the Reader. This procedure is known as Anti-collision and it is a key technology in the RFID system. In this paper, we propose the 4-Bit Pattern Slot Allocation(4-BPSA) algorithm for the high-speed identification of the multiple tags. The proposed algorithm is based on the tree algorithm using the time slot and identify the tag quickly and efficiently through accurate prediction using the a slot as a 4-bit pattern according to the slot allocation scheme. Through mathematical performance analysis, We proved that the 4-BPSA is an O(n) algorithm by analyzing the worst-case time complexity and the performance of the 4-BPSA is improved compared to existing algorithms. In addition, we verified that the 4-BPSA is performed the average 0.7 times the query per the Tag through MATLAB simulation experiments with performance evaluation of the algorithm and the 4-BPSA ensure stable performance regardless of the number of the tags.

• Journal of Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.431-441
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• 1988

The purpose of this study was to compare the difference of two survey methods for health services research. Data were collected by means of two types of household survey conducted from March 11 to September 19, 1985. A probability sample of 30,613 persons was taken from 180 Enumerated Districts designated by the Economic Planning Board. The sample was divided into two groups systematically. One group was surveyed by the self-administered questionnaire and the other group was interviewed. Response rates were 81.4% and 90.6% respectively. The data were analysed by the ratio of the results of the self-administered survey to those of the interview survey. No difference was observed in sex, age, residence, or occupation between the two groups. However the respondents' characteristics were statistically different between the two groups. The major findings of this study are as follows : 1. The morbidity rate was 142.5 per 1,000 persons during the two week period by the self-administered questionnaire survey and 74.3 per 1,000 persons with the interview survey method. The ratio of the morbidity rate by the self-administered questionnaire to that by the interview was 1.92, and the difference between the two rates were due to the personal characteristics. 2. The out-patient utilization rate was 10.2 visits per person per year by the self-administered questionnaire survey and 5.4 by the interview survey, and the ratio was 1.89; the admission rate was 3.2 times per 100 persons per year by the self-administered questionnaire survey and 1.9 times by the interview survey, and the ratio was 1.68. Differences due to the sociodemographic characteristics were greater in the out-patient utilization rates than in the adimssion rates. 3. Percentages of effective medical care demand were 90.2% in the self-administered survey and 92.3% in the interview survey; the ratio was 0.98 which was less than that of the morbidity rate and medical care utilization. But, differences of effective medical care demand occurred in persons with no occupation, and aged or low educated respondents. 4. Respiratory illness had the highest frequency in the two survey methods. But there was a slight difference between the two survey methods in morbidity composition. 5. It was concluded that data collected by the interview survey were inclined to be underestimated and this problem can be corrected by a modified self-administered survey.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.107-117
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• 2004

The growing demand for customer-response, made-to-order manufacturing and satisfactory delivery are stimulating the importance of commercial fleet management problem. Moreover, the rapid transformation to the customer-oriented multi-frequency, relatively small fleet, such as home delivery and Perishable goods, requiring prompt delivery and advanced real-time operation of vehicle fleets. In this paper we consider the vehicle routing problem(VRP) to minimize delivery completion time which is equal to the time that last customer wait for the vehicle in fleet operation. The mathematical formulation is different from those for the classical VRP which is minimizing cost/distance/time by running vehicles in manager's point of view. The key aspect of this model is not considering the return time from the last customer to depot in every vehicle path. Thereby, the vehicle dispatcher can afford to dynamically respond to customer demand and vehicle availability. The customer's position concerned with minimizing waiting time that may be applied for the delivery of product required freshness or delivery time. Extensive experiments are carried out to compare the performance of minimizing delivery completion time by using the ILOG Solver which has the advantage of solving quickly an interim solution very near an optimal solution. The experimental results show that the suggested model can easily find near optimal solution in a reasonable computational time under the various combination of customers and vehicles.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.323-333
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• 2015

Objective : The purpose of this study was to investigate the changes of gait patterns and muscle activations with increased loads during stair walking. Also, it can be used as descriptive data about continuous stair walking in a real life setting. Method : Twelve sedentary young male adults(Age: $27.0{\pm}1.8yrs$, Weight: $65.8{\pm}9.9kg$) without any lower extremity injuries participated in this study. Participants performed stair walking up 7 floors and their ascending and descending motion on each floor was analyzed. A wireless electromyography(EMG) were attached on the Rectus Femoris(RF), Biceps Femoris(BF), Gastrocnemius(GN), Tibialis Anterior(TA) muscle to calculate integrated EMG(iEMG), median frequency(MDF) and co-contraction index(CI). Chest and left heel accelerometer signal were recorded by wireless accelerometer and those were used to calculate approximate entropy(ApEn) for analyzing gait pattern. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was LSD. Results : During ascending stairs, there were a statistically significant difference in Walking time between 1-2nd and other floors(p=.000), GN iEMG between 2-3th and 6-7th(p=.043) floor, TA MDF between 1-2nd and 5-6th(p=.030), 6-7th(p=.015) floor and TA/GN CI between 2-3th and 6-7th(p=.038) floor and ApEn between 1-2nd and 6-7th(x: p=.003, y: p=.005, z: p=.006) floor. During descending stairs, there were a statistically significant difference in TA iEMG between the 6-5th and 3-2nd(p=.026) floor, and for the ApEn between the 1-2nd and 6-7th(x: p=.037, y: p=.000, z: p=.000) floor. Conclusion : Subjects showed more regular pattern and muscle activation response caused by regularity during ascending stairs. Regularity during the first part of stair-descending could be a sign of adaptation; however, complexity during the second part could be a strategy to decrease the impact.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.2
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• pp.87-104
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• 2000

The purpose of this study was to obtain the basic data as a improvement method through the fact-revealing concerning the drinking water management of school and utilization of student. The problems of the research are as follows: First, to investigate status of management of drinking water by area and school. Second, to investigate student's utilization of drinking water by area and school. 1,400 students was selected at 45 elementary and middle-high schools located in Kang-won province, and this study was constituted of two questionnaires(for school's questionnaire and student's questionnaire). The results was analyse through the frequency analysis, $x^2$-test on the basis of the above research problem by SPSS program. The findings of this research are as follows; 1) The Management of School Drinking Water First, the source of school drinking water was mostly piped water. Inspection of water quality has been fulfilled under four times a year, in the other hands, from the result inspection, the schools which was given inadequate determination was 22.2%. Second, reservoir cleaning and hygiene inspection failed far short of the regulations. Especially, reservoir cleaning was managed by exterior consignment industry not low-level officials. Third, school water drinking was the most supplied through the type of water purifier. Water purifier has been distributed to city-located and middle-high school highly, factually the water from water purifier was served with water cup. Fourth, the selection standard of water drinking manager showed slightly differently by school, accordingly there need to develope integrated system with the respective to its effective systematic management. Fifth, water cup was mostly treated by only water clear, which is to vindicate the problems concerning hygiene management. 2) Utilization of school student on Drinking Water First, Disbelief on drinking water of school student was very high. Especially, proportion of middle-high school student's disbelief of drinking water was higher than elementary school student, also girls higher than boys. Many of student have heard to don't drink water from around people. And there were showed meaningful differences by area and school. Second, It was showed many student recognize had to utilize water purifier, boiled water. However, they have still drunken the tap water or portable water from their home. Third, Many of student showed negative response with the respective to the management conditions of drinking water in classroom, There were showed meaningful differences by area and school. From the fact-revealing of water cup management, Students mostly answered to 'only water clear' and the answer of 'None use' or 'With personal cup' was higher. Fourth, In bad experience of Drinking Water, student mostly answered to 'occasionally' and there were showed meaningful differences by school. student's disease experience with school drinking water was few and there were showed meaningful differences by area and gender.

• Journal of agricultural medicine and community health
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• v.16 no.2
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• pp.165-171
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• 1991

Two patients with confirmed cerebral cysticercosis were treated with Albendazole(Zentel$^{(R)}$) at a daily dose of 1.200mg t.i.d. for 14 consecutive days and evaluated for tolerance and therapeutic effects. First case was 29 year old male, who had experience of 4 times of grand mal seizures during 1 year period before administration in Korea University Hospital. His chief complaints were seizure and moderate degree headache. He also had 4 subcutaneous nodules on the thorax, right and left upper arms. Among them one nodule was biopsied and confirmed microscopically as Cysticercus cellulosae hominis. Computed tomography of the brain showed four round low density lesions in right postero-frontal area, sylvian area, intra-occipital area and left parietal area. Second case was 48 year old male, who also had experience of seizures at 3 years, 5 months and 3 months before administration. In this case, no subcutaneous nodules and no headaches were noted. Brain CT showed four round low density lesions in right postero-parietal area and temporo-parietal area, and left temporo-parietal and parietal area. Serum antibody against cystic fluid antigen was detected by ELISA in both cases. The efficacy of the treatment of cerebral cysticercosis was assessed by the frequency of convulsions after treatment for 22 months follow-up. by the disappearance of the densities in cystic lesions at brain CT for 6 months follow-up, and disappearance of subcutaneous nodules, headache and so on. As the results, all low density lesions in both cases were disappeared in films of brain CT, and 4 nodules in first case were also disappeared. No more seizure and complain of headache occurred during the last 22 months after treatment in both cases. Post-treatment complete blood count and liver function test revealed no remarkable change compared to pre-treatment test. In the nations of Latin America, the physicians do not initially recommended the simultaneous administrations of steroids, reserving them only for patients whom the adverse reactions such as severe headache and/or seizures are occurred. According to them, in most patients these symptoms are controlled with aspirin and symptomatic drugs. But our experience using praziquantel is different, and most cerebral cysticercosis patients who takes PZQ had complaint of severe headache and sometimes seizure. So we simultaneously used dexamethasone as 6mg q.i.d. for 14 consecutive days and 6 days tapering thereafter in both cases for prevention of reactions produced by the host in response to the deaths of the parasites. As the conclusion, albendazole is effective in patients who presented cerebral cysticercosis and albendazole may help in the control of cysticercosis.