• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.201-207
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• 2018

There is no known polynomial time algorithm for random-type quadratic assignment problem(RQAP) that is a NP-complete problem. Therefore the heuristic or meta-heuristic approach are solve the approximated solution for the RQAP within polynomial time. This paper suggests polynomial time algorithm for random type quadratic assignment problem (QAP) with time complexity of $O(n^2)$. The proposed algorithm applies one-to-one matching strategy between ascending order of sum of distance for each location and descending order of sum of quantity for each facility. Then, swap the facilities for reflect the correlation of distances of locations and quantities of facilities. For the experimental data, this algorithm, in spite of $O(n^2)$ polynomial time algorithm, can be improve the solution than genetic algorithm a kind of metaheuristic method.

• Wind and Structures
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• v.10 no.4
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• pp.301-314
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• 2007

The lever-type active multiple tuned mass dampers (LT-AMTMD), consisting of several lever-type active tuned mass dampers (LT-ATMD), is proposed in this paper to attenuate the vibrations of long-span bridges under the excitation directly acting on the structure, rather than through the base. With resorting to the derived analytical-expressions for the dynamic magnification factors of the LT-AMTMD structure system, the performance assessment then is conducted on the LT-AMTMD with the identical stiffness and damping coefficient but unequal mass. Numerical results indicate that the LT-AMTMD with the actuator set at the mass block can provide better effectiveness in reducing the vibrations of long-span bridges compared to the LT-AMTMD with the actuator set at other locations. An appealing feature of the LT-AMTMD with the actuator set at the mass block is that the static stretching of the spring may be freely adjusted in accordance with the practical requirements through changing the location of the support within the viable range while maintaining the same performance (including the same stroke displacement). Likewise, it is shown that the LT-AMTMD with the actuator set at the mass block can further ameliorate the performance of the lever-type multiple tuned mass dampers (LT-MTMD) and has higher effectiveness than a single lever-type active tuned mass damper (LT-ATMD). Therefore, the LT-AMTMD with the actuator set at the mass block may be a better means of suppressing the vibrations of long-span bridges with the consequence of not requiring the large static stretching of the spring and possessing a desirable robustness.

• Journal of Chest Surgery
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• v.50 no.6
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• pp.430-435
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• 2017

Background: Mycotic aortic aneurysms are rare and life-threatening. Unfortunately, no established guidelines exist for the treatment of patients with mycotic aortic aneurysms. The purpose of this study was to evaluate the midterm outcomes of the open repair of mycotic thoracic and thoracoabdominal aneurysms and suggest a therapeutic strategy. Methods: From 2006 to 2016, 19 patients underwent open repair for an aortic aneurysm. All infected tissue was extensively debrided and covered with soft tissue. We recorded the clinical findings, anatomic location of the aneurysm, bacteriology results, antibiotic therapy, morbidity, and mortality for these cases. Results: The median age was $62{\pm}7.2years$ (range, 16 to 78 years), 13 patients (68%) were men, and the mean aneurysm size was $44.5{\pm}4.9mm$. The mean time from onset of illness to surgery was $14.5{\pm}2.4days$. Aortic continuity was restored in situ with a Dacron prosthesis (79%), homograft (16%), or Gore-Tex graft (5%). Soft-tissue coverage of the prosthesis was performed in 8 patients. The mean follow-up time was $43.2{\pm}11.7months$. The early mortality rate was 10.5%, and the 5-year survival rate was $74.9%{\pm}11.5%$. Conclusion: This study showed acceptable early and midterm outcomes of open repair of mycotic aneurysms. We emphasize that aggressive intraoperative debridement with soft-tissue coverage results in a high rate of success in these high-risk patients.

• The Journal of the Korean dental association
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• v.47 no.8
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• pp.522-533
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• 2009

Purpose: Infection with HIV-1 virus has become a critical worldwide public health problem. The oral complications of HIV infection with its progression of impairment of the host response to combat infection present unique challenges to the periodontists. Material and Methods : Medline research was carried out to find relationship of the progression of HIV infection to the occurrence of oral lesions including the HIV-related periodontal diseases. Results: The linear gingival erythema, necrotizing ulcerative periodontitis, necrotizing ulcerative gingivitis and oral candidiasis are common lesions in HIV-infected individuals. The linear gingival erythema and necrotizing ulcerative periodontitis lesions in HIV-infected subjects were found to have a similar microbiological profile. There are several general considerations in the periodontal management of the HIV-infected patient with or without periodontal disease. The altered immunity and host response in patients with HIV infection may also affect the incidence and severity of other common forms of periodontal disease not associated with HIV infection. Conclusion: Periodontal diseases in HIV-infected individuals present unique challenges in diagnosis, monitoring, treatment and maintenance. Therefore exact HIV staging, geographic location, antiviral and antimicrobial therapies and oral habits should be taken into consideration when treating HIV-infected patients.

• Journal of the Korean Geographical Society
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• v.32 no.4
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• pp.561-572
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• 1997

This paper attempts to analyze the changes of the contents in foreign area research carried out by Korean geographers, and discuss the task of the new regional geography in a global-local context. As compared with domestic area research, only a scant of foreign area research has been carried out. In the 1990's, the research interests are paid to how an open economy affects the regional economy, especialy the production technique, division of labor, industrial mix, market strategy, industrial location and organization, and so on. Unfortunately, however, the boundaries between economic geography and regional economy are gradully disappearing.

• Korea Journal of Hospital Management
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• v.9 no.1
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• pp.22-45
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• 2004

This study was performed to identify factors affecting the profitability of private hospitals in Korea different and to make informations that could be very helpful to hospitals in improving profitability. Data used in this study were collected from 112 hospitals with complete general data of present conditions as well as financial statements(balance sheets, income statements). They were chosen from hospitals that passed the standardization audit undertaken by the Korean Hospital Association from 1998 to 2001 for the purpose of accrediting training hospitals. The dependent variables were used operating margin to total assets and operating margin to gross revenues as proxy indicators for profitability. The independent variables were ownership type, location, bed size, period of establishment, debt to total assets, current ratio, fixed ratio, total asset turnover, average length of stay, bed occupancy rate, admission ratio of outpatients, personnel costs per adjusted inpatient, and fiscal years. The factors had significantly positive effect on operating margin to total assets and operating margin to gross revenues were bed size, total asset turnover. And the factors had significantly negative effect on operating margin to total assets and operating margin to gross revenues were period of establishment, debt to total assets, average length of stay, personnel costs per adjusted inpatient. The adjusted $R^2$ of multiple regression equation was 25.2%, 21.4% respectively. It is very important for private hospitals to improve profitability by raising total asset turnover, and reducing debt to total assets, average length of stay, and personnel costs per adjusted inpatient using the rational and efficient business strategy.

• Convergence Security Journal
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• v.16 no.2
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• pp.25-34
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• 2016

This study aims to prevent the serious threat from dangerous person or group by responding or blocking or separating illegal activities by use of SNA: Social Network Analysis. SNA enables to identify the complex social relation of suspect and individuals in order to enhance the effectiveness and efficiency of investigation. SNS has rapidly developed and expanded without restriction of physical distance and geo-location for making new relation among people and sharing large amount of information. As rise of SNS(facebook and twitter) related crimes, terrorist group 'ISIS' has used their website for promotion of their activity and recruitment. The use of SNS costs relatively lower than other methods to achieve their goals so it has been widely used by terrorist groups. Since it has a significant ripple effect, it is imperative to stop their activity. Therefore, this study precisely describes criminal and terrorist activities on SNS and demonstrates how effectively detect, block and respond against their activities. Further study is also suggested.

• Korean Journal of Community Nutrition
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• v.10 no.5
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• pp.668-676
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• 2005

The purpose of this study was to determine the relationship between the students' levels of involvement in school lunch service and their satisfaction levels with the service. A survey was conducted with $5^{th}\;and\;6^{th}$ grade elementary students eating school lunches. Out of 1,680 questionnaires distributed to the students from 14 schools, 1,254 complete questionnaires $(74.6\%)$ were analyzed. The questionnaire included two 5-point multi-item scales for measuring levels of involvement in and satisfaction with school lunch service, respectively. A factor analysis grouped 20 items measuring school lunch satisfaction into three factors: 'food satisfaction', 'nutrition & sanitation satisfaction', and 'service & environment satisfaction'. As a result of multiple regression analyses controlling the influence of such variables as students' grades, gender, school location, years and places of eating school lunches, students' levels of involvement in school lunch service was proven to be positively associated with levels of school lunch satisfaction overall, as well as satisfaction levels in regard to 'food', 'nutrition & sanitation', and 'service & environment', respectively. It was suggested that efforts such as nutrition education to increase students' levels of involvement in school lunches could be a useful strategy to improve students' satisfaction with school lunch service.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.817-822
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• 2014

Since the opening of the double-track railway for the Gyeongchun local electric train and the semi-high speed train ITX, floating population between Seoul and Chuncheon has rapidly increased. This is attributable to the competitiveness of the railway service in terms of punctuality and safety of operation, mass transportation and low fare. However, many passengers have expressed strong dissatisfaction and displeasure towards the interior noise and its high rate of increase, particularly in tunnel sections. In this study, the interior noise characteristics of Gyeongchun local electric train and ITX were analyzed and compared. Noise levels, frequency spectrum and sound quality indices were compared for the open land, tunnel and bridge. Finally, from the noise levels depending on the location in the vehicle compartment, the noise transmission path was determined and a basic strategy for reducing the interior noise was developed.

• Journal of Trauma and Injury
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• v.32 no.4
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• pp.210-219
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• 2019

Purpose: Traumatic diaphragmatic injury (TDI) is no longer considered to be a rare condition in Korea. This study investigated differences in the prevalence of accompanying injuries and the prognosis in patients with traumatic diaphragmatic damage according to the mechanism of injury. Methods: We retrospectively reviewed the medical records of patients with TDI who were seen at a regional emergency medical center from January 2000 to December 2018. Among severe trauma patients with traumatic diaphragmatic damage, adults older than 18 years of age with a known mechanism of injury were included in this study. Surgery performed within 6 hours after the injury was sustained was defined as emergency surgery. We assessed the survival rate and likelihood of respiratory compromise according to the mechanism of injury. Results: In total, 103 patients were analyzed. The patients were categorized according to whether they had experienced a penetrating injury or a blunt injury. Thirty-five patients had sustained a penetrating injury, and traffic accidents were the most common cause of blunt injuries. The location of the injury did not show a statistically significant difference between these groups. Severity of TDI was more common in the blunt injury group than in the penetrating injury group, and was also more likely in patients with respiratory compromise. However, sex, the extent of damage, and the initial Glasgow coma scale score had no significant relationship with severity. Conclusions: Based on the findings of this study, TDI should be recognized and managed proactively in patients with blunt injury and/or respiratory compromise. Early recognition and implementation of an appropriate management strategy would improve patients' prognosis. Multi-center, prospective studies are needed in the future.