• 한국정보통신학회논문지
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• 제24권8호
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• pp.1113-1116
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• 2020

In the EH-WSN(Energy Harvesting Wireless Sensor Network), the routing protocol must consider the power condition of nodes such as residual power and energy harvesting rate. Many EH-WSN studies have emphasized the power aspect and make the urgency of sensed data less important. However, in applications such as environmental monitoring, stability and latency become more important issues than power efficiency for urgent data. In this paper, we designed a routing protocol that can set path according to data urgency. To this end, relay nodes are determined considering the urgency of date. Nodes with poor power do not participate in routing when normal data is generated, so that urgent data can be transmitted reliably with low latency. The performance of the proposed routing protocol is analyzed by computer simulation.

• 항공우주의학회지
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• 제31권1호
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• pp.13-16
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• 2021

The coronavirus disease-19 (COVID-19) vaccine is expected to play an important role in stopping the pandemic. Studies show that COVID-19 vaccines are effective at keeping you from getting COVID-19. Getting a COVID-19 vaccine will also help keep you from getting seriously ill even if you do get COVID-19. Efforts to find an effective vaccine against severe acute respiratory syndrome coronavirus 2 have progressed unprecedentedly through active support from public research grants and private-public partnership programs. Clinical studies have been actively conducted, and some vaccines are being vaccinated with approval for urgent use. The WHO has approved and supplied the Pfizer-BioNTech COVID-19 vaccine and the Oxford-AstraZeneca COVID-19 vaccine. In Korea, the Oxford-AstraZeneca vaccine was approved for urgent use, and vaccination began on February 26, 2021. In this paper, the efficacy and side effects of each vaccines and the effect on pilots and air traffic controllers related to COVID-19 vaccination were investigated in terms of aviation medicine.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2010년도 춘계학술대회
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• pp.1-4
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• 2010

• 한국공간구조학회지
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• 제16권2호
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• pp.12-17
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• 2016

• 한국인터넷방송통신학회논문지
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• 제10권1호
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• pp.97-105
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• 2010

본 논문에서는 IEEE 802.11 기반의 네트워크에서 긴급 메시지 전송을 위한 효율적인 매체 접근 기법을 제안한다. 본 논문에서 제안한 기법의 주요한 특징은 다음과 같다. 첫째, 매체 접근에 있어서 높은 우선순위를 할당받기 위해 표준화 문서에서 정의한 것보다 짧은 기간의 프레임 간격을 갖는다. 둘째, 지수적으로 증가하는 백오프 윈도우가 아닌, 고정된 크기의 윈도우를 사용한다. 제안된 기법의 성능평가는 시뮬레이션을 통하여 이루어졌으며, 평가를 위한 비교대상은 표준화 문서에서 정의한 기법을 사용하는 노드이다. 성능평가 결과, 제안된 기법을 사용하는 노드는 경쟁에 참여하는 노드 수가 늘어남에 따라 기존의 기법을 사용하는 노드와 비교하여 보다 적은 매체 접근 지연시간을 갖는다. 또한 지연시간의 감소로 인하여 동일한 크기의 데이터를 전송하기 위한 시간이 줄어듦으로 처리량에서도 향상을 가져왔다.

• 한국전자통신학회논문지
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• 제13권3호
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• pp.509-516
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• 2018

TCP는 메시지 전송에 광범위하게 쓰이는 잘 알려진 송수신 프로토콜이다. TCP의 긴급 메커니즘은 우선순위가 높은 메시지를 전송할 때 규칙 역할을 한다. 긴급 메커니즘은 우선순위가 높은 메시지의 발생 사실을 수신 노드에 미리 알려줌으로써 수신 노드로 하여금 미리 준비하도록 돕는다. 하지만 TCP의 긴급 메커니즘은 우선순위가 높은 메시지의 즉시 또는 빠른 전송을 보장하지는 않는다. 따라서 TCP에 보통 메시지의 신뢰적인 전송과 메시지의 우선순위에 따른 차별 전송 기능을 제공하기 위에 우선순위 기반 전송의 기능이 필요하다. 본 논문은 TCP 프로토콜을 위한 멀티 쓰레드 환경에서의 우선순위 규를 이용한 우선순위 기반 전송 알고리즘을 제안한다. 제안된 알고리즘의 효율성은 다른 우선순위 레벨을 가진 여러 메시지를 전송하는 실험 환경을 통해 검증되었다.

• Journal of Chest Surgery
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• 제47권5호
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• pp.451-457
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• 2014

Background: The balance of the risks and the benefits of cardiac surgery in the elderly remains a major concern. We evaluated the early and mid-term clinical results of patients aged over 75 years who underwent major cardiovascular surgery. Methods: Two hundred and fifty-one consecutive patients, who underwent cardiac surgery at Seoul National University Bundang Hospital between July 2003 and June 2011, were included in this study (mean age, $78.7{\pm}3.4$ years; male:female=130:121). Elective surgery was performed in 112 patients, urgent in 90, and emergency in 49. Results: Early mortality was 12.7% (32/251). Follow-up completion was 100%, and the mean follow-up duration was $2.8{\pm}2.2$ years. Late mortality was 24.2% (53/219). There were 283 readmissions in a total of 109 patients after discharge. However, the reason for readmission was related more to non-cardiac factors (71.3%) than to cardiac factors. The overall survival estimates were 79.2% at the 1-year follow-up and 58.4% at the 5-year follow-up. Patients who underwent elective surgery had a lower early mortality rate (elective, 4.5%; urgent, 13.3%; emergency, 30.6%) and better overall survival rate than those that underwent urgent or emergency surgery (p<0.001). Conclusion: The timing of cardiac surgery was found to be an independent risk factor for early and late mortality. Thus, earlier referral and intervention may improve operative results. Further, comprehensive coordinated postoperative care is needed for other comorbid problems in aged patients.

• 한국정보통신학회논문지
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• 제5권5호
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• pp.951-959
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• 2001

비디오 데이터베이스는 비디오 정보를 저장하고 있다가 사용자가 요구한 비디오 정보를 검색해 주는 기능을 갖는다. 따라서, 비디오 데이터베이스의 목적은 비디오정보를 저장하고 검색하기 위한 편리하고도 효율적인 환경을 제공해야 할 뿐만 아니라 보다 많은 사용자들에 대해서 보다 신속하게 요구결과들을 검색해 줄 수 있어야 한다. 그러나, VOD응용과 같은 비디오 데이터베이스의 사용자들은 1시간이나 2시간 정도의 비디오 시청을 위하여 어느 정도의 시작지연은 감수할 수 있다. 본 논문에서는 비디오 데이터베이스의 사용자등급을 구분하여 효율적으로 서비스할 수 있는 비디오 데이터 베이스의 하부 저장시스템을 제안한다. 제안하는 저장시스템은 다중 디스크 환경 하에서 급박한 등급의 사용자들에게는 디스크헤드의 임의이동을 허용하고 VOD응용과 같은 덜 급박한 등급의 사용자들에게는 디스크헤드의 순차적 이동을 유지함으로써 급박한 사용자들에게 빠른 응답을 제공할 뿐만 아니라 전체적으로 보다 많은 사용자들을 지원할 수 있다.

• Journal of Chest Surgery
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• 제53권1호
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• pp.1-7
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• 2020

Background: The aim of this study was to evaluate the short-term and long-term results of surgical treatment for native valve endocarditis (NVE) and to investigate the risk factors associated with mortality. Methods: Data including patients' characteristics, operative findings, postoperative results, and survival indices were retrospectively obtained from Hallym University Sacred Heart Hospital. Results: A total of 29 patients underwent surgery for NVE (affecting the mitral valve in 20 patients and the aortic valve in 9) between 2003 and 2017. During the follow-up period (median, 46.9 months; interquartile range, 19.1-107.0 months), the 5-year survival rate was 77.2%. In logistic regression analysis, body mass index (p=0.031; odds ratio [OR], 0.574; 95% confidence interval [CI], 0.346-0.951), end-stage renal disease (ESRD) (p=0.026; OR, 24.0; 95% CI, 1.459-394.8), and urgent surgery (p=0.010; OR, 34.5; 95% CI, 2.353-505.7) were significantly associated with in-hospital mortality. Based on Cox proportional hazard regression analysis, the statistically significant predictors of long-term outcomes were hypertension, ESRD, and urgent surgery. Conclusion: Surgical treatment for NVE is associated with considerable mortality. The in-hospital mortality and 5-year survival rates of this study were 13.8% and 77.2%, respectively. Underlying conditions, including hypertension and ESRD, and urgent surgery were independent risk factors for unfavorable outcomes.

• 보건행정학회지
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• 제7권2호
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• pp.46-64
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• 1997

Background & Objectives : Korea is face with the social need for health care technology assessment so that it is urgently needed to found principles and methodology in technology assessment in health care. As a groundwork for health care technology assessment, we tried to prioritize medical technology for assessment. Among medical technologies, procedure is somewhat difficult to assess, compared to drug or equipment. In this study, we aimed at the prioritisation of medical procedure to be assessed, in terms of efficay, safety, and adequacy. Method : For the standardized classification of medical procedure, ICD-9-CM(International Classification of Diseases 9th edition - Clinical Modification) was used. Among the list the procedures coming under otorhinolaringjology and thoracic surgery were selected by three family physicians. The list of procedure was mailed to the board certified surgeons of both disciplines, with the question asking about the necessity for assessment in terms of efficay, safety, and adequacy. Replied questionnaires were analyzed in each procedure. Results : Of 560 otorhinolaryngologist and 480 thoracic surgeon, 114 surgeons replied. Of otorhinolaryngological procedure, incision, excision, and destruction of inner ear : fenestration of inner ear : stapedectomy and its revision were the most urgent technology to assess in the aspect of safety. For adequacy, operations on Eustachian tube: fenestration of inner ear: incision, excision, and destruction of inner ear were highly ranked in necessity, and for efficary, operations on Eustachian tube; external maxillary antrotomy; fenestration of inner ear. Thoracic surgeons replied thoracic procedures, lung transplantation; heart transplantation; implantation of heart assist system [pump] are most important for evaluation in terms of safety; and heart transplantation; Lung transplantation; Implantation of heart assist system [pump] in terms of adequacy, and surgical collapse of lung [Artificia니 pnemothorax or pnuexoperitoeum]; lung transplantation; periarterial sympathectomy in terms of efficacy. As a whole, surgeons regard safety evaluation is more urgent than adequacy or efficary. In addition, otorhinolaryngological surgeons regard evaluation of their procedures more urgent than thoracic surgeons regard theirs. Conclusion : By the questionnaire to board certified physicians, we get some preliminary data for prioritisation of technologies to assess. Through the questionnaire like this, much information would be gathered for technology assessment, especially for medical procedure, if not enough. In the near future, well structured expert opinion gathering research, such as modified Delphi or nominal group technique, should be done succeedingly.