• 대한조선학회논문집
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• 제43권3호
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• pp.351-361
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• 2006

The fatigue strength analysis of VLFS is carried out by using a 3-dimensional plate finite element model with a zooming technology which performs the modeling of wide portions of the structure by a coarse mesh but the concerned parts by a very fine mesh of t by t level. And a stepwise substructure modeling technique for global loading conditions is applied which uses the motion response of the global structure from 2-D plate hydroelastic analysis as the enforcing nodal displacements of the concern 3-D structural zooming model. Seven incident wave angles and whole ranges of frequency domains of wave spectrum are considered. In order to consider the effect of breakwater, the modified JONSWAP wave spectrum is used. Applying the wave data of installation region, the longterm spectrum analysis is done based on stochastic process and the fatigue life of the structure is estimated. Finally some design considerations from the view point of fatigue strength analysis of VLFS are discussed.

• 수산해양기술연구
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• 제43권3호
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• pp.222-231
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• 2007

This paper represents a basic statistical examination on the navigability of ocean-going ship from the point of estimating the time lasting period when propeller racing occurred by using the basic probability theory and the statistics. The propeller racing is one of the most important seakeeping qualities in relation to the safety of the main engine and shafting system. The trend of the racing has been mainly investigated in order to estimate allowable maximum propeller diameter, operation of ocean-going ships, etc.. In those studies, the propeller racing generally and mainly means the situation (propeller exposed) in which the relative motion amplitude between ship hull and wave surface would exceed a depth of point in rotary disk propeller. Therefore, it seems that the magnitude of the amplitude and its exceeding frequency of propeller racing have been examined as a principal subject of study as usual. However, the time during which the amplitude exceeds the depth of point, that is, the propeller exposes in the air, must be also one of most important factor affecting the trend of propeller racing. Then, this paper proposes a new practical method for estimating the time lasting of exposed propeller related to propeller racing in rough-confused seas on the basis of the linear strip theory and the statistics. And, numerical examples of estimating the propeller racing probability are given for four wide ship forms. Finally the usefulness of the proposed method for predicting propeller racing based on the time lasting period is discussed.

• 콘크리트학회논문집
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• 제23권2호
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• pp.225-233
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• 2011

콘크리트는 타설 직후부터 온도 및 수분의 변화로 인한 체적 변화가 일어난다. 특히 초기 재령에서 발생하는 온도 수축과 건조 수축은 콘크리트에 균열을 유발할 수 있으며, 이는 콘크리트 내구성에 큰 영향을 끼친다. 중국에서는 저온에서 소성된 산화마그네슘(MgO) 분말을 시멘트 대체재로 사용한 콘크리트를 구조물에 적용할 경우, 수축에 대한 보상 효과를 얻을 수 있는 것으로 보고된 바 있다. 이 연구에서는 실험을 통하여 저온 소성한 MgO를 혼입한 시멘트 복합체의 다양한 특성을 규명하고자 하였다. 안정성 시험 결과 MgO 분말의 혼입에 따른 이상팽창이 유발되지 않음을 확인하였으며, MgO의 수화생성물 분석을 통해 MgO 분말이 장기 재령에서 수축을 보상하는 것을 확인하였다. 또한 적당한 MgO 분말의 혼입은 시멘트 복합체의 압축강도를 증진시키는 효과가 있었으며, MgO 분말의 혼입률이 높거나 양생 온도가 높을수록 MgO 분말의 팽창성에 따른 수축 보완 효과가 크게 나타났다.

• 보건행정학회지
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• 제23권2호
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• pp.132-144
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• 2013

Background: The purpose of this study was to analyze the medical expense change and influencing factors after introducing longterm care insurance system. The study period was 2 years before and after introduction of the system. Methods: We analyzed data collected from two divided group lived in Incheon. Four hundred and eighty-five elderly who received long-term care wage for one year were selected for experimental group. For control group, 1,940 elderly were selected by gender and age stratified random sampling. Difference-In-difference analyses was used for evaluating policy effectiveness. Also multiple regression analyses were conducted to identify the factors associated with total medical expenditures. The control variables were demographic variables, economic status, diseases, and medical examination variables. Results: Difference-in-difference analyses showed that total average medical expenses among long-term patients has decreased by 61.85%. Of these, the hospitalization expenses have decreased by 91.63% and the drug expenses have increased by 31.85%. Multiple regression analyses results showed that total average medical expenses among long-term patients have significantly decreased by 46.5% after introducing the long-term care insurance. The hospitalization expenses have significantly decreased by 148.5%, whereas the drug expenses have increased by 53.6%. And outpatient expenses have increased by 10.4%, but the differences were not statistically significant. Conclusion: The results showed that total medical expenses and hospitalization expenses have decreased after introducing the long-term care insurance. These results could support the opinion that the health insurance spending among long-term patients will be reduced gradually by long-term care insurance through changing medical demand.

• 한국식품과학회지
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• 제19권3호
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• pp.206-211
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• 1987

건조김의 품질을 향상시키고 저장안정성을 높이기 위하여 수세물량을 달리하여 건조김을 제조하고$30^{\circ}C$와 $5^{\circ}C$에서 포장방법별로 6개월동안 저장하면서 품질변화 특성을 조사하였다. 건조김의 단분자층 수분함량을 $5^{\circ}C$와 $25^{\circ}C$에서 구해본 결과 각각 7.4%와 6.4%로 나타났다. 저장효과는 원료김을 충분한 물로 수세하여 수분함량을 단분자층 이하로 낮추어 가능한한 낮은 온도에서 저장하는 것이 바람직 하였으며 포장방법에 있어서는 진공포장이 함기포장에 비하여 품질유지가 다소 좋은 것으로 나타났다.

• 한국물환경학회지
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• 제26권6호
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• pp.895-902
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• 2010

The effect of seasonality on water quality variation is very significant. Generally, it reduce the power of the trend extraction. A parametric time-series model was used for detecting trends in historic constituent concentration data. The effect of seasonality is able to remove from time series decomposition technique. According to such statistic methode, long-term water quality trend analysis system (NTrend 1.0) was developed by Nakdong River Water Environmental Research Center. The trend analysis of BOD variation was conducted with NTrend 1.0 at Goreong and Moolkum site in Nakdong river to show the effect of water quality management action plan. Power test of trend extraction was tried each case of 'deseasonalized and deannulized' data and 'deseasonalized' data. Analysis period was from 1989 to 2006, and it's period was divided again three times, 1989~1993, 1994~1999 and 2000~2006 according to action plan period. The BOD trend was downward in Goreong site during three times and it's trend slope was very steep, and upward in Moolkum during 1989~1993, but it was turned downward during 1994~1999 and 2000~2006. It was revealed that it's very effective to reduce the concentration of BOD by water quality management action plan in that watershed. The result of power test was shown that it is high for trend extraction power in case of 'deseasonalized' data.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권4호
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• pp.30-38
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• 2010

This study was conducted to determine the potential applicability of slowly released molasses (SRM) to treat nitratecontaminated groundwater. SRM was made by dispersing molasses in hydroxy propyl methyl cellulose-silicamicrocrystalline cellulose matrix. Column test indicated that SRM could continuously release molasses with slowly decreasing release rates of $64.6mg-COD/L{\cdot}h$ up to 65 hrs, $12.1mg-COD/L{\cdot}h$ up to 215 hrs, and $4.4mg-COD/L{\cdot}h$up to 361 hrs. A batch test using an isolated indigenous heterotrophic denitrifier Pseudomonas sp. KY1 having nitrite reductase (nirK) and liquid molasses demonstrated that the bacterium decreased 100 mg-N/L of nitrate to less than 10 mg-N/L at the C/N ratio of 10/1 in 48 hours. In a Pseudomonas sp. KY1-attached Ottawa sand column which continuously received molasses from a SRM-containing reservoir, the bacterium successfully removed nitrate from 20 mg-N/L to 3 mg-N/L during the 361 hours of column operation. The results showed the possibility that SRM can be used as a reliable, longterm extra carbon source for indigenous heterotrophic denitrifiers.

• Journal of Chest Surgery
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• 제31권11호
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• pp.1081-1084
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• 1998

연구배경 : 식도암은 근치율이 낮고, 광범위 림프절 절제후에도 그 성적이 나쁜 편이다. 따라서 경부 림프절 절제가 식도수술결과에 미치는 효과를 알아보고자 식도수술 환자에서 경부림프절 전이가 된 환자를 조사하였다 대상 및 방법 : 1994년부터 1996년 6월까지 본원에서 흉부식도암 수술을 받은 32명의 환자 중 고식적 수술을 시행받은 25명의 환자를 대상으로 하여 경부림프절 절제의 유무를 기준으로 두 그룹으로 나뉘어 연구하였다. 두 그룹 모두 흉부식도 전절제술과 동반하여 종격림프절과 복부림프절 절제를 시행하였으나 B그룹은 양측 경부림프절 절제를 추가하여 시행하였다. 결과 : 수술합병증은 두 그룹 사이에서 의미있게 차이가 나지않았다. t수술사망과 병원사망은 두 그룹 모두에서 보이지 않았다. 그러나 평균 마취시간은 B그룹에서 의밌게 더 길었다.(평균 마취시간 90분). B그룹에서 27%가 경부림프절 전이를 보였다 결론 : 그러므로 경부림프절 절제는 흉부식도암 수술에서 의미있는 수술방법이라고 할 수 있다. 장기생존율의 비교가 더 필요하리라고 생각한다.

• 보건행정학회지
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• 제4권2호
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• pp.27-57
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• 1994

The objective of running a long-term care institution is to provide services helpful for maintaining, supporting, and improving elderlies' optimum level of physical, mental, and psychosocial functioning. For the purpose of analyzing the current situations of institutional long term care facilities in Korea, 27 facilities were selected proportionately from each of the cities and provinces, out of the total 152 facilities. About 20% of those who were institutionalized during 25 August through 2 Qctober 1993, the 391 elderlies were chosen on a systematic random basis. The instrument of this study was developed by modifying the tools of CARE, MAI and PCTC. A multivariate approach of discriminant analysis and clustering technique were employed for this study. The Stiudy reveals that there is no clear differentiation of goals and functions among the longterm care institutions in Korea. Staffing patte군 of long-term care facilities shows a shortage of nurses, physical therapists, and dieticians. The linkage between acute care facilities and long-term care is weak, and administration of long-term care faciltiy is carried out by non-professionals. They are responsible for assessing health status before entering the facility, and evaluating elderlies' care. Therefore, it is not surprising to find that most of the facilities have accommodated agede regardless of their real needs and health status. Based upon findings of the analysis, this study has classified long-term care facilities into four types : Type I is to help elderlies maintain independence in daily living activities. Type II facilities have the objective of maintaining and improving the current level of elderlies' function. Type III is to maintain maximum independence of elderlies in activities of daily living. And Type IV is identified for the group of facilities designed to restore or improve functional abilities of elderlies. In conclusion, the following suggestions are made : the need for long-term care should be assessed by multidimensional measurement. Institutional long-term care facilities should be classified and developed in response to type of type of care and service need. Both acute and long-term care facilities should be linked together in order to support the evaluation of service operation and program development.

• Journal of Korean Neurosurgical Society
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• 제61권1호
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• pp.19-27
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• 2018

Objective : The objectives of this study were to evaluate the immediate and long-term efficacy and safety of coil embolization for large or giant aneurysms. Methods : One hundred and fifty large or giant aneurysm cases treated with endovascular coil embolization between January 2005 and February 2014 at a single institute were included in this study. Medical records and imaging findings were reviewed. Statistical analysis was performed to evaluate prognostic factors associated with major recurrence (major recanalization or rupture) and delayed thromboembolism after selective coil embolization. Results : Procedure-related symptomatic complications occurred in five (3.3%) patients. The mean clinical and radiological follow-up periods were 38 months (range, 2-110) and 26 months (range, 6-108), respectively. During the follow-up period, the estimated recurrence rate was 4.6% per year. Multivariate analysis using Cox regression showed the degree of occlusion to be the only factor associated with recurrence (p=0.008, hazard ratio 3.15, 95% confidence interval 1.34-7.41). The patient's history of rupture in addition to the size and location of the aneurysm were not associated with recurrence in this study. Delayed infarction occurred in eight cases, and all were incompletely occluded. Conclusion : Although immediate postprocedural safety profiles were reasonable, longterm results showed recanalization and thromboembolic events to occur continuously, especially in patients with incomplete occlusion. In addition, incomplete occlusion was associated with delayed thromboembolic complications. Patients with incomplete occlusions should be followed carefully for delayed recurrence or delayed thromboembolic events.