• Tuberculosis and Respiratory Diseases
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• 제83권2호
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• pp.167-174
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• 2020

Background: The purpose of this study was to investigate the effect of early tracheostomy on clinical outcomes in patients requiring prolonged acute mechanical ventilation (≥96 hours). Methods: Data from 575 patients (69.4% male; median age, 68 years), hospitalized in the medical intensive care unit (ICU) of a university-affiliated tertiary care hospital March 2008-February 2017, were retrospectively evaluated. Early and late tracheostomy were designated as 2-10 days and >10 days after translaryngeal intubation, respectively. Results: The 90-day cumulative mortality rate was 47.5% (n=273) and 258 patients (44.9%) underwent tracheostomy. In comparison with the late group (n=115), the early group (n=125) had lower 90-day mortality (31.2% vs. 47.8%, p=0.012), shorter stays in hospital and ICU, shorter ventilator length of stay (median, 43 vs. 54; 24 vs. 33; 23 vs. 28 days; all p<0.001), and a higher rate of transfer to secondary care hospitals with post-intensive care settings (67.2% vs. 43.5% p<0.001). Also, the total medical costs of the early group were lower during hospital stays than those of the late group (26,609 vs. 36,973 USD, p<0.001). Conclusion: Early tracheostomy was associated with lower 90-day mortality, shorter ventilator length of stay and shorter lengths of stays in hospital and ICU, as well as lower hospital costs than late tracheostomy.

• 한국건축시공학회지
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• 제14권6호
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• pp.591-596
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• 2014

본 연구는 현재 사회적 문제가 되고 있는 도시재생 사업의 매몰비용 관련 인식 조사를 목적으로 실시하였다. 조사결과 지방정부, 중앙정부, 정치권, 조합원 및 토지 등 소유자 모두 매몰비용에 관하여 일정부분 책임과 부담 의무의 필요성이 있는 것으로 나타났다. 매몰비용에 대한 지원은 어느 하나의 주체에게 책임을 전가하기보다 정비 사업에 참여했던 주체 모두가 함께 책임을 통감하여 문제가 되고 있는 매몰비용의 부담과 해결 방안까지 공유해야하는 것으로 나타났다. 공공은 매몰비용에 대해 직접적인 지원보다는 간접적 지원(기반시설 부담, 세제혜택, 규제기준 완화 등)을 통하여 조합 등이 사업 추진의 지속 여부에 대하여 합리적인 선택을 할 수 있도록 유도하여야 하여야 할 것이다.

• Journal of Korea Trade
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• 제25권3호
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• pp.1-20
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• 2021

Purpose - The purpose of this paper is to examine the welfare effects of standards harmonization between technologically asymmetric countries, and to determine optimal harmonization strategies for a country with mid-level technological advancement. Design/methodology - Following Salop's circular city model (Salop, 1979), this study constructs a simple, horizontally-differentiated oligopoly model in which three firms and three countries exist. Each country adopts different compatibility standards and each firm incurs conversion costs for foreign market access due to differences in standards. The conversion costs are related to technology; standards harmonization removes these costs between participating countries. The paper considers three cases: i) no harmonization; ii) harmonization with the more technologically-advanced country and iii) harmonization with the less technologically-advanced country. Findings - The paper first considers a scenario in which all three firms occupy some share of the market in each country. It shows that standards harmonization with both the technologically moreor less-advanced country always increases consumer surplus and social welfare. In addition, the producer surplus will increase if the harmonization partner has a higher technology level, whereas it may decrease if the partner has a lower technology level. It also shows that if most domestic export goods are in sectors with conversion costs above a certain level, harmonizing standards with a technologically more-advanced country should be prioritized. Such strategies, moreover, should be emphasized when there exists a large technology gap among countries. Lastly, the paper considers another scenario, in which harmonization leads to the foreclosure of the non-member firm from the member countries' markets. It shows that harmonization improves the social welfare of a mid-level technology country regardless of its partner's technology. It also shows that the country should prioritize harmonization with the technologically less-advanced country. Originality/value - Though some of the existing studies consider the welfare effects of harmonization, their main assumption is that firms have the same conversion technology. Since complying with standards often requires substantial technological advancement and technical expertise, harmonization of compatibility standards between countries with gaps in technological ability carries different implications. This paper investigates the welfare effects of this harmonization and determines an optimal harmonization strategy while considering technological asymmetry among countries in standards compliance.

• 대한교통학회지
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• 제32권5호
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• pp.513-521
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• 2014

우리나라의 교통혼잡비용은 매년 급격히 증가하고 있으며, 이를 해결하기 위한 방안으로 정부는 대중교통 이용활성화 를 적극 장려하고 있는 실정이다. 대중교통은 혼잡비용 절감에 중요한 사회적 역할을 담당하고 있으나, 많은 승객을 수송하는 수단이므로 교통사고 발생시 그 심각도가 매우 높다. 이러한 대중교통의 사고 주 원인으로는 버스운전자의 업무부담 과중으로 인한 전방 및 측방 주시태만이 대표적이다. 이러한 사고요인을 제거하기 위해 대중교통 HUD를 개발하였다. 버스에 활용이 가능하도록 수직면에 가까운 자동차 윈드실드에 정보표출이 가능한 광학 및 광원 기술을 개발하였으며, 버스 운전자가 필요로 하는 표출 콘텐츠를 선정하였다. 또한 뇌파분석 등을 통해 표출정보의 시인성 향상을 위한 색상을 도출하였다. 본 연구를 통해 개발된 대중교통 HUD는 버스 등 대중교통의 운전자 업무부담을 감소시키고, 전방으로 시야를 집중시킴으로써 교통사고 감소에 기여할 수 있을 것으로 판단된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제22권4호
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• pp.377-386
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• 2019

Purpose: Percutaneous liver biopsy (PLB), a diagnostic procedure to identify several hepatobiliary disorders, is considered safe with low incidence of associated complications. While postoperative monitoring guidelines are suggested for adults, selection of procedural recovery time for children remains at the discretion of individual operators. We aim to determine if differences exist in frequency of surgical complications, unplanned admissions, and healthcare cost for children undergoing outpatient PLB for cohorts with same-day vs. overnight observation. Methods: We performed a retrospective cohort study in children 1 month to 17 years of age undergoing ultrasound-guided PLB from January 2009 to August 2017 at a tertiary care, pediatric referral center. Cohorts were defined by postprocedural observation duration: same-day (${\leq}8$ hours) vs. overnight observation. Outcomes included surgical complications, medical interventions, unscheduled hospitalization within 7 days, and total encounter costs. Results: One hundred and twelve children met study criteria of which 18 (16.1%) were assigned to same-day observation. No differences were noted in demographics, anthropometrics, comorbidities, biopsy indications, or preoperative coagulation profiles. No major complications or acute hospitalizations after PLB were observed. Administration of analgesia and fluid boluses were isolated and given within 8 hours. Compared to overnight monitoring, same-day observation accrued less total costs (US $992 less per encounter). Conclusion: Same-day observation after PLB in children appears well-tolerated with only minor interventions and complications observed within 8 hours of procedure. We recommend a targeted risk assessment prior to selection of observation duration. Same-day observation appears an appropriate recovery strategy in otherwise low-risk children undergoing outpatient PLB.

• Composites Research
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• 제34권2호
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• pp.96-100
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• 2021

The lightweight industry continuously demands reliable near-net-shape fabrication where the preform just out-of-machine is close to the final shape. In this study, different half-finished preforms are made π-beams. Then the preforms are unfolded to make a 3D shape with integrated structure of fibers, providing easier handling in the further processing of composites. Several 3D textile preforms are made using weaving technique and are examined after resin infusion for mechanical properties such as inter-laminar shear strength, compressive strength and tensile strength. Considering that the time and labor are important parameters in modern production, 3D weaving technique reduces the manufacturing steps and therefore the costs, such as hand-lay up of textile layers, cutting, and converting into preform shape. Hence this 3D weaving technique offers many possibilities for new applications with efficient composite production.

• 산업경영시스템학회지
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• 제35권1호
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• pp.10-15
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• 2012

This paper considers an economic design problem of a tree-based network which is a kind of computer network. This problem can be modeling to be an objective function to minimize installation costs, on the constraints of spanning tree and maximum traffic capacity of sub tree. This problem is known to be NP-hard. To efficiently solve the problem, a tabu list coupled genetic algorithm approach is proposed. Two illustrative examples are used to explain and test the proposed approach. Experimental results show evidence that the proposed approach performs more efficiently for finding a good solution or near optimal solution in comparison with a genetic algorithm approach.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.470-481
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• 2016

Field-programmable gate arrays (FPGAs) have received much attention from the nuclear industry as an alternative platform to programmable logic controllers for digital instrumentation and control. The software aspect of FPGA development consists of several steps of synthesis and refinement, and also requires verification activities, such as simulations that are performed individually at each step. This study proposed an integrated software-testing framework for simulating all artifacts of the FPGA software development simultaneously and evaluating whether all artifacts work correctly using common oracle programs. This method also generates a massive number of meaningful simulation scenarios that reflect reactor shutdown logics. The experiment, which was performed on two FPGA software implementations, showed that it can dramatically save both time and costs.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.327-337
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• 2005

Accelerated life test models and procedure are developed to assess the reliability of Door switch. The main function of door switch is to operate bulb lamp and fan motor. The accelerated life test method and test equipments are developed using the relationship between stresses and life characteristics of the products. Using the developed accelerated life test method, the parameters of the ALT model and life time distribution are estimated and the reliability of the Door S/W at use condition if assessed. The proposed accelerated life test method and procedure may be extended and applied to testing similar kinds of products to reduce test time and costs of the tests remarkably.

• ETRI Journal
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• 제27권2호
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• pp.140-152
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• 2005

In this paper, we present design features, implementation, and validation of a satellite simulator subsystem for the Korea Multi-Purpose Satellite-2 (KOMPSAT-2). The satellite simulator subsystem is implemented on a personal computer to minimize costs and trouble on embedding onboard flight software into the simulator. An object-oriented design methodology is employed to maximize software reusability. Also, instead of a high-cost commercial database, XML is used for the manipulation of spacecraft characteristics data, telecommand, telemetry, and simulation data. The KOMPSAT-2 satellite simulator subsystem is validated by various simulations for autonomous onboard launch and early orbit phase operations, anomaly operation, and science fine mode operation. It is also officially verified by successfully passing various tests such as the satellite simulator subsystem test, mission control element system integration test, interface test, site installation test, and acceptance test.