• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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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.

• Korean journal of aerospace and environmental medicine
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• v.31 no.1
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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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• 2010.05a
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• pp.1-4
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• 2010

• Journal of Korean Association for Spatial Structures
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• v.16 no.2
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• pp.12-17
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• 2016

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.97-105
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• 2010

This paper proposes an effective medium access mechanism which is based on IEEE 802.11 to transmit an urgent message, The main features of the proposed mechanism are as follows. First, when it comes to channel access to have high priority, it has a shorter interval between frames than that specified in standard document. Second, we use fixed window size instead of back-off window with an exponential increase. Performance evaluation of proposed mechanism is executed by simulation and compare with the node using the specified mechanism in standard document. Performance evaluation results show that according to increasing competition the nodes using proposed method have less accessing time than the conventional methods. Also, the proposed method can improve processing time because of the decreasing transmission delay.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.509-516
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• 2018

TCP is a well-known communication protocol which is widely used for reliable message transmissions. The urgent mechanism of TCP plays a key role to transmit messages with a high priority. If a high priority message occurs at the transmitting node, the urgent mechanism informs the receiving node about the presence of a high priority message prior to its transmission so that the receiving node can be prepared for handling this message in advance. This implies that the existing urgent mechanism of TCP does not guarantee an immediate or faster delivery of the high priority message itself. Therefore, the ability of priority-based transmission is required on TCP not only to ensure reliable transmissions of normal messages but also to offer a differentiated service according to the priority of message. This paper presents a priority-based transmission algorithm over TCP using a priority queue in a multi-threaded environment. The effectiveness of the proposed algorithm is explored using an experimental setup in which various messages with different priority levels are transmitted.

• Journal of Chest Surgery
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• v.47 no.5
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.951-959
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• 2001

Video database has the function that stores videos and retrieves the video informations for the service request of users. Therefore, the purpose of the video database is to provide not only an environment both convenient and efficient for retrieving and storing video, but also to serve the requested video informations with rapid startup latency for more users. But, some users of video database as VOD application might tolerate slow startup latency because they would watch video during one hour or two hours. In this paper, we propose the novel policy of the storage system of video database, which serves efficiently the users by considering the classes of the users in video database. The policy admits the random movements of disk heads for urgent user classes but maintains the sequential or restricted movements of disk heads for less-urgent user classes like VOD application in storage system of video database. So, it can not provide only rapid startup latencies for urgent requests but also it can process more service requests in all.

• Journal of Chest Surgery
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• v.53 no.1
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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.

• Health Policy and Management
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• v.7 no.2
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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.