• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.347-350
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• 2006

The rocket grade hydrogen peroxide has been widely used as a monopropellant in propulsion systems. In the present paper, we described an experimental study of a catalytic reactor that employs two stage catalyst beds to enhance the low temperature performance of the reactor. $K_2MnO_4$ was chosen as the catalyst for the initial stage of the reactor bed for its superior behavior in the low temperature regime. LSC was used for the catalyst of the second stage of the reactor. The gas generator with combined catalyst beds was built and tested to exhibit high decomposition efficiency over 90% and successful cold-start characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.163-170
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• 2011

Applicability of regenerative cooling in 2,500 N-class bipropellant thruster using hydrogen peroxide and kerosene was considered for improvement performance and application in various missions. Calculation was performed by one dimensional approach using hydrogen peroxide as a coolant. In designed regenerative cooling thruster, heat flux at nozzle throat was estimated at 18 ~ 20 $MW/m^2$. Designed cooling channel width and height were 2.5 mm and 0.5 mm, respectively. Based on designed cooling channel configuration, flat plate model was manufactured and tested for estimation of pressure drop in cooling channel, and CFD analysis was compared with the test result. The maximum error between CFD analysis and experimental result was approximately 13% and average error was approximately 5%.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.59-63
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• 2009

Purpose: This study was designed to compare the relative accommodation, the accommodative facility, and the addition whose 40's initial presbyopia divided into five occupations (driver, official worker, housewife, field worker, teacher). Methods: We measured the values of near point convergence (NPC), positive relative accommodation (PRA), negative relative accommodation (NRA), accommodative facility, and addition. Results: Official worker group had lower PRA, higher NRA, and lower accommodative facility compared with them of the other groups. The average of addition was as follows: official worker > driver > field worker > housewife > teacher. Conclusions: Because the difference of working environment based on occupation affects the accommodative functions and addition, it is important to consider the patient's occupation when opticians measure the addition for near vision of initial presbyopia.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.27-31
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• 2009

Purpose: The purpose of this study was to document the importance of work capability and the educational needs for optometric duty. Methods: Questionnaires were distributed to 813 optometrists and 89 full-time faculties on nation wide in July, 2008. Results: Statistical analysis showed that high mean of 3.53, maximum of 4, for the importance of work capability, and 3.46 for the educational needs as for the total optometric duty. Especially, optometric dispensing was the highest on the importance of work capability and the educational needs, where as medical ethics and optometric jurisprudence and business management was the lowest. Conclusions: Both optometrists and full-time faculties agreed to the importance of work capability and the educational needs, and therefore it should be reflected in optometric education program.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.350-351
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• 2008

현재 우리나라의 측량체계는 크게 측지분야와 지적분야로 이원화되어 있으며 측지분야에서는 2001년도에 측량법을 개정하여 ITRF2000좌표계와 GRS80 타원체를 측량기준으로 사용하는 세계측지계를 도입하였다. 하지만 지적 분야에서는 국민의 재산권과 직접적으로 관련이 있는 필지의 경계와 면적의 변화 연구는 미미한 상태이다. 따라서 본 연구는 2010년 세계측지계 도입 후 지적분야에서 발생할 수 있는 필지별 면적 변동에 따른 사회적 혼란 여부를 판단하기 위하여 서울특별시 종로구 숭인등 숭인4구역주택재개발지구를 연구 대상지로 선정하여 세계측지계 전환에 지적 필지별 면적 변화를 분석하였다. 분석결과 연구대상지는 세계측지계와 지역측지계가 종선(X)축으로 305.87m. 종선(Y)축으로 70.87m 편차로 두 좌표계 간 북동방향으로 313.97m의 차이가 있고, 현행성과와 비교한 결과 종선(X) 방향으로는 평균 +4.0cm, 횡선(Y) 방향으로는 평균 -3.0cm의 차이가 나타났으며, 필지별 면적의 변동량은 $1.0m^2{\sim}3.0m^2$ 차이가 있지만 허용오차 범위 내에 있으므로 세계측지계 전환에는 문제점이 없는 것으로 판단된다. 하지만 본 연구의 결과는 그 대상범위가 한정되어 있고 기 검증된 지적기준점 성과를 사용한 결과이므로, 향후 보다 효율적인 세계측지계 전환과 도입을 위해서는 현 지적기준점체계의 정확한 세계좌표계 변환 성과를 기준으로 한 대단위의 필지별 면적 변동량 및 허용범위 분석과 같은 추가적인 연구가 조속히 이루어져야 할 것으로 판단된다.

• Journal of Chest Surgery
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• v.29 no.3
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• pp.346-349
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• 1996

This 32 year old female patient underwent left radical mastectomy due to ductal carcinoma on May 1990, and treated with FAM (5-fluorouracil, Adriamycin and Mitomycin C) regimen postoperatively. However, right cervical Iymph node enlargement and facial edema progressively developed since December 199). On April 1994, operation was performed, and findings were as followes; x4$\times$5$\times$7 to 1 : 1 $\times$ 1 cm sized multiple enlarged and hyperemic Iymph nodes were scatterred throughout submandibular area to the junction of superior vents cave and pericardium, and partially invaded both anterior segmental lobe, sternum and both distal tip of clavicles. After radical dissection of the nodes of neck and mediastinal nodes, and wedge resection of both anterior segments of lung, and partial resection of both clavicle tips and total sternum. The both innominate veins and superior vena cava were partially obstructed by invaded cancer SVC reconstruction was done with preclotted 10$\times$ 10$\times$ 18mm Y shap d woven Dacron graft, which was anastomosed to the point of the junction of subclavian vein and jugular vein after cross clamping both veins and 2cm above the pericardial junction with one arm clamp. After maintaining blood drainage to the SVC from the right side, left innominate vein was anastomosed with 4-0 Prolene continuous running suture. Bone cement was used for resected sternal portion and clavicular ends were fixed to postal portion with 18 Gauge wires. The patient was treated with radiation and chemotherapy after discharge, and there were no evidence of regrowing of the mass nor obstruction of the graft inspite of no antithrombotic therapy.

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.22-28
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• 2011

This study aimed to determine the feasibility of survey questionnaires for pesticide poisoning. We conducted a pilot study to develop a questionnaire for evaluating pesticide poisoning symptoms and to examine the validity of self-reported information for individual pesticides used. In December 2010 we interviewed 20 farmers with self-reported pesticide poisoning histories residing in Gyeonggi Province. For validity of pesticide information, the purchased pesticide lists from the agricultural cooperative federation were compared with individual self-reported pesticides used. Neurological symptoms were the most common among clinical symptoms related to pesticide poisoning, followed by gastrointestinal, dermal and eye symptoms. Insecticides were the main causative pesticide class for poisoning. Twenty one major symptoms were selected for screening for acute pesticide poisoning in a field study based on the pilot results and literature reviews. Substantial under-reporting was found in data on self-reported individual pesticides used (9.2%), as well as low accuracy (36%) compared with their actual purchase lists. In this pilot study, we suggest the selected symptom lists may apply to a field survey of pesticide poisoning. However, the self-reported information on individual pesticides may not be valid and alternative methods need to be developed.

• Korean Journal of Social Welfare
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• v.62 no.3
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• pp.5-29
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• 2010

This study examines the welfare dynamics in Korea under the scheme of National Basic Livelihood Protection Program(NBLP). Data are drawn from Korean Welfare Panel study 2005~2007. Main findings are summarized as follows. First, the exit probabilities show a declining tendency with time on welfare increases. If the exit probabilities indeed decline over time, the earlier years on welfare deserve more interest in the policy perspective. Moreover, the vast majority of recipients are long-termers. Further efforts are needed to increase self-sufficiency through providing genuine opportunity and necessary support for recipients. Second, out-of-poverty exit and out-of-system exit are quite different in their properties. The results from the multivariate analysis confirm that the dropouts through out-of-system exit are virtually the same with those who remain on welfare. These results imply that the government should not resort to the negative policy proposals such as time limit and strengthening sanctions. Third, several explanatory variables have anticipated effect on welfare exit probabilities. Age, education, health, marital status, the presence of children, employment status have a certain level of impact on exit, with the only exception of gender. Since the identification of the determinants can facilitate sensible targeting on the potential leavers, these results have some implications on policy proposals.

• Korean Journal of Social Welfare
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• v.63 no.4
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• pp.83-107
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• 2011

This study examines the duration dependence in the exit rate from National Basic Livelihood Protection Program(NBLP). If the length of time on welfare is negatively correlated with the exit rate after controlling for 'unobserved heterogeneity', the observed declining exit rates would provide evidence of true duration dependence. Data are drawn from Korean Welfare Panel study 2005~2008. A variety of discrete-time hazard models are estimated, including parametric/nonparametric hazard model, gamma frailty hazard model/mass point technique model. It is found that welfare dynamics in Korea does not show strong evidence of duration dependence after controlling for unobserved heterogeneity. All the models estimated show that this finding is quite robust. The observed declining exit rate is largely due to differences in the unobservable characteristics of recipients. Thus, the detrimental effect of the welfare on the preference and attitude among recipients is not likely to be strengthened as time on welfare increases.

• Korean Journal of Social Welfare
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• v.62 no.4
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• pp.249-274
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• 2010

This study examines a casaul relationship between depression and welfare transitions of the National Basic Likelihood Protection Program. From a social selection perspective, prior high levels of depression are likely to select people into welfare or serve as a barrier to leaving welfare. From a social causation perspective, entering or exiting welfare can change the levels of depression. These hypotheses were tested using KOWEPS(Korean Welfare Panel study) 2005~2007. The results are as follows. First, entering welfare clearly increases the levels of depression. The increased economic stress resulting from falling into poverty seems to play a major role in the negative effect of welfare entry. Second, exiting welfare does not decrease the levels of depression. However, when welfare exits are classified into distinctive categories, welfare exit combined with concurrent poverty exit is likely to decrease the levels of depression. Third, high levels of depression clearly increase the probability of entering welfare regardless of the prior poverty status. Fourth, high levels of depression do not decrease the probability of exiting welfare, but rather increase the probability of an administrative disentitlement which leads to even worse economic conditions after exiting welfare. One implication of these findings is that negative policies such as time limit and strengthening sanctions can increase the number of welfare cyclers who are able-bodied but mentally weak.