• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.775-783
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• 2005

이동통신 네트워크의 위치영역 설계는 위치관리 비용을 최소화하도록 네트워크를 위치영역으로 분리하는 문제이다. 기존 위치영역 설계 관련 연구는 설계의 모수가 되는 호 발생률 및 셀 간 가입자 이동률을 고정된 것으로 가정하였다. 그러나 실제 환경에서의 두 모수는 시간에 따라 변화하고, 일정한 패턴을 나타내며, 시간 당 셀 내 인구에 영향을 받는다. 본 연구에서는 이러한 인구유동 및 호 발생의 불확실성 및 시간에 따는 패턴 변화를 고려하여 기준 이상의 페이징 서비스 품질을 만족시키고, 비용을 최소화 하는 위치영역 설계 방식을 제안하였다. 모수의 변동에 일정 서비스 품질을 보장하기 위해 시간대 및 가동률 상한의 개념을 도입하여 추계적 문제를 정적 그래프 분리문제로 변환하였고, 이에 대한 솔루션은 Simulated Annealing을 응용한 경험적 최적해 도출 알고리즘을 이용하여 도출했다.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.165-165
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• 2009

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.142.1-142
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• 2003

저장 중 단감은 과피 및 과육의 변색 발생으로 인한 품질저하가 심각하게 발생하고 있는데, 아직까지 이를 방지하기 위한 원인 규명은 매우 미흡한 실정이다. 이에 본 연구에서는 단감의 재배지, 수확시기, 크기, 예조기간, 저장온도, 저장기간, 포장재의 두께 등을 달리하여 저장하면서 처리조건에 따른 단감 과육의 갈변 발생 관련성을 조사하였다. 단감의 변색발생 증상은 저장 1개월 이후부터 일부 나타나기 시작하여 저장기간이 경과할수록 심하였다. 단감의 갈변 발생률 및 갈변 정도를 실험 처리구별로 살펴보면 과수원, 수확시기, 예조기간, 저장온도, 포장재의 두께, 포장 내 가스조성에 따라 차이를 보였는데 단감의 수확시기가 늦을수록, 수확후 예조기간이 짧을수록, 저장을 위해 사용한 포장필름의 두께가 얇을수록 갈변발생정도가 심하였다. 또한 단감의 과수원에 따라서도 갈변의 발생률이 차이를 보여 동일지역이더라도 재배조건에 의하여서도 영향을 받는 것으로 나타났다. 이와 같은 결과를 종합하여 보면 단감 과육의 갈변발생은 수확 전 및 수확 후 인자들의 단독적인 영향이기보다는 복합적인 영향에 의한 것으로 추정되었다.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.102-111
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• 2005

The purpose of this study was to assess the incidence of flare-ups among patients who received endodontic treatment and to examine the correlation with pre-operative and operative variables. Analysis was in two aspects (a) overall incidence of flare-ups as expressed by a percentage of all patients visits and (b) percentage of flare-ups that occurred as related to various factors suck as patient demo-graphics, diagnosis, and treatment procedures. 1. From the 840 teeth which were examined in this study, the total number of flare-ups was 13. 2. As to gender of patients, there was no significant difference in flare-ups. 3. As to tooth groups, there was no significant difference in flare-ups. 4. In the teeth with pre-operative symptom, there was a statistically significant higher incidence of flare-ups than the teeth without it. 5. In the teeth with apical periodontitis, there was a statistically significant higher incidence of flare-ups. 6. As to pulp and periapical status. non-vital teeth had a higher incidence as compared with vital teeth, irreversible pulpitis. 7. Multi-visit treatment resulted in the higher incidence of flare-ups than one visit treatment. 8. Re-treatment procedures had a statistically significant higher incidence of flare-ups than root canal treatment. In this study, overall percentages of flare-ups was $1.55\%$. It showed a statistically significant higher incidence related to pre-operative symptom, apical periodontitis, and re-treatment. There was no significant difference in flare-ups related to gender, tooth groups, and fistula.

• Journal of agricultural medicine and community health
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• v.45 no.4
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• pp.235-244
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• 2020

Objectives: Gyeongsangbuk-do has entered a super-aged society with 20.7% of the population aged 65 and older. As of April 30, 2020, the death rate of COVID-19(3.8 people) in Gyeongsangbuk-do is higher than the national mortality rate (2.3 people), and the fatality rate of COVID-19 by age accounts for more than half of the total of 58.6%, so it is time to propose to prevent infectious diseases in the event of additional infectious disease disasters COVID-19. Methods: We collected daily data on the number of confirmed cases and deaths due to COVID-19 from 19 February to 30 April 2020. The data collected was evaluated using the SPSS 21.0 statistical package. Results: As a result of comparing the incidence and death-related factors of confirmed patients in Gyeongsangbuk-do, there were significant differences in age group (p<0.001), underlying disease (p<0.001), and residence type (p<0.033). Conclusion: Factors affecting the mortality rate of confirmed patients in Gyeongsangbuk-do have been combined with individual level factors(age, gender, underlying disease), which means individual characteristics that have existed since before the disease, and regional level factors(Type of Residence), which are external factors that enable the use of medical resources. Therefore, each local government is required to establish preventive measures considering individual and regional level factors.

• Journal of the military operations research society of Korea
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• v.35 no.2
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• pp.33-49
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• 2009

The objective of this study is as follows. First, the hazard function on the failure probability density function of the K-1 tracked vehicles can be occurred in the form of the bathtub curve. Second, the failure mode may be different under two different operational situations. The research result shows that the bathtub curve can be fitted in the Weibull distribution, that assumes different shapes according to the specific stage of the system's life cycle. The K-1 tracked vehicle has a relatively high hazard(failure) rate at the time of its first service. The failure rate starts decreasing for a time immediately after it goes into service. After the break-in period, the surviving components have a fairly constant hazard rate. As the K-1 system ages, deterioration of its various parts takes place and the hazard rate starts Increasing. Second, the result shows the failure rate in the harsh operational environment is higher than that in the mild operational environment. In conclusion, the bathtub curve can be logically appropriate in establishing the depot overhaul cycle. Moreover, it is necessary for determining the right time of the depot overhaul to consider not only the age of defense equipment but also the different operational environment.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.338-344
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• 2001

배경: 말기 신부전 환자에서 심장병, 특히 관상 동맥 질환의 이환이 늘어나면서 관상동맥 우회수술의 대상 환자가 지속적으로 증가하고 있다. 이들 환자군은 수술후 유병률과 사망률이 매우 높고 고위험군으로 알려져 있다. 대상 및 방법: 1996년 3월부터 2000년 5우러까지 서울 중앙 병원 흉부외과에서 술전 말기 신부전증으로 진단 받은 후 관상 동맥 우회수술을 시행받은 환자 25명을 대상으로 의무 기록을 중심의 후향적 분석을 하였다. 술전 위험 인자 및 술전 신기능, 수술 결과, 술후 경과, 수술후 합병증, 사망률 및 생존률 등을 분석하였다. 결과: 술전 평균 크레아티닌 청소율은 12.7$\pm$5ml/mim였고 술전 평균 혈중 크레아티닌 치는 6.2$\pm$3mg/dl(1.7-14.4)였다. 술전 투석을 시행중인 환자는 11례(44%)였고 술전 투석을 시행하지 않았던 14례(56%)중 8례(8/14, 57.1%)는 수술전후로 새로이 투석이 필요하였다. 술전 혈액 투석 중이었던 9례중 2례에서 수술후 복막 투석으로 전환하였다. 수술 사망률은 2례(8%)로 흡인성 폐렴과 종격동염으로 1례, 그리고 수술후 출형과 종격도염으로 1례가 사망하였다. 수술후 합병증은 14명(56%)의 환자에서 발생하여 매우 높은 발생율을 보였다. 만기사항은 2례(8%)에서 발생하였으며 사망원인은 카테터에 의한 복막염이었다. 생존 환자의 4년 생존률은 82$\pm$13% 였다. 결론: 말기 신부전 환자에서의 관상동맥 우회수술을 비교적 만족스러운 범위의 수술 사망률(8%)을 보였으나 합병증 발생률이 매우 높고 합병증 발생 시 사망률이 매우 높아 수술주위 감염 예방과 세심한 환자 관리가 필요하다.

• 종축개량
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• v.12 no.9 s.79
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• pp.54-57
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• 2007

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.291-298
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• 2002

This study was carried out to investigate the reproductive status and the effect of progesterone treatment on the recovery of reproductive disorders in Hanwoo. Hanwoo farms were surveyed the general management status, such as the type of barn, the feed intake, the incidence of reproductive disorders. The reproductive disorder cattle were treated 7 days insertion of control internal drug releasing for cattle (CIDR) and injection of PGF$_2$$\alpha$ at 1 day before removal. The recovery of reproductive disorders was assessed by determining the pregnancy following artificial insemination. The total number of surveyed Hanwoo farms was 127, and the total incidence rate of reproductive disorders was 19.7% (209/1,061). Compared to the herd size, the incidence rates of reproductive disorders in less than 10 heads (37.5%) was significantly (P<0.05) higher than in 10 to 20 heads (14.7%) and more than 20 heads (13.6%) of herd size per farm. The incidence rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than in free stall barn (30.4% vs. 14.7%), and even in free stall barn, that tended to decrease as the floor area was larger. The incidence rate of reproductive disorder by the parity was highest in heifer (50.7%), and that tended to decrease as the parity was increased. The distribution rate of the case of reproductive disorder in anestrus, recovery rate of reproductive disorders fellowing CIDR treatment was 75.1% (157/209). In the recovery rate of reproductive disorders by body condition score (BCS), BCS 1, 2 and 3 was significantly (P<0.05) higher pregnancy rate (85.7, 84.9 and 86.8%), and gross recovery rate in emaciated cattle was better than in obese cattle (BCS 4, 5). In conclusion, the incidence rate of reproductive disorders in Hanwoo raised in Youngju province area was 19.7%, and that tended to decrease as the herd size was increase because of increased farmer's attentions, and the floor area was larger. The majority of the case of reproductive disorders was anestrus. The recovery rate of reproductive disorders following CIDR treatment was 75.1%, and to optimize the recovery rate of reproductive disorders, cows and heifers were maintained BCS 1, 2 and 3 by moderate management.

• Explosives and Blasting
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• v.42 no.1
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• pp.23-33
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• 2024

Recently, various techniques and patented methods on blasting operation are being newly developed. In this study, test construction of the MDS blasting method was performed, and the fragmentation size and the occurrence rate of rocks exceeding 300mm were measured and analyzed in comparing to normal blasting method. Test construction was performed three times each for normal and the MDS at the same bench for each round, and fragmentation size(P80) and occurrence rate of rocks exceeding 300mm(S30) were measured using digital image processing. A sieve bucket was also manufactured on-site to sort oversized rock particles from muck piles, and their weights and equivalents were measured to calculate actual values. As a result, the fragmentation size decreased of 21.0% with the MDS compared to normal, and 100-S30 decreased of 10.1%, with actual values decreasing of 7.6%. Although there were variations in blasting effects for each round due to differences in rock quality at site, overall, the MDS proved to be more effective compared to normal blasting method under equivalent conditions.