• Journal of Chest Surgery
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• 제45권3호
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• pp.161-165
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• 2012

Background: Median sternotomy can weaken the upper abdominal wall and result in subxiphoid incisional hernia. We evaluated risk factors associated with the development of subxiphoid incisional hernias after coronary artery bypass grafting (CABG). Materials and Methods: Of 1,656 isolated CABGs performed between January 2001 and July 2010, 1,599 patients who were completely followed up were analyzed. The mean follow-up duration was $49.5{\pm}34.3$ months. Subxiphoid incisional hernia requiring surgical repair developed in 13 patients (0.8%). The hernia was diagnosed $16.3{\pm}10.3$ months postoperatively, and hernia repair was performed $25.0{\pm}26.1$ months after the initial operation. Risk factors associated with the development of subxiphoid incisional hernia were analyzed with the Cox proportional hazard model. Results: Five-year freedom from the hernia was 99.0%. Univariate analysis revealed that female sex (p=0.019), height (p=0.019), body surface area (p=0.046), redo operation (p=0.012), off-pump CABG (p=0.049), a postoperative wound problem (p=0.041), postoperative bleeding (p=0.046), and low cardiac output syndrome (p<0.001) were risk factors for the development of the hernia. Multivariable analysis showed that female sex (p=0.01) and low cardiac output syndrome (p<0.001) were associated with subxiphoid hernia formation. Conclusion: Female sex and postoperative low cardiac output syndrome were risk factors of subxiphoid hernia. Therefore, special attention is needed for patients with high-risk factors.

• 품질경영학회지
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• 제39권3호
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• pp.391-399
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• 2011

Our study was carried out to analyze the variation factors of severity-adjusted length of stay(LOS) in coronary artery bypass graft(CABG). The subjects were 932 CABG inpatients of the Korean National Hospital Discharge In-depth Injury Survey from 2004 through 2008. The data were analyzed using $x^2$ test and the severity-adjusted model was developed using data mining technique. The results of the study were as follows: male(71.1%), older than 61 years of age(61.6%), more than 500 beds(92.8%) and admitting via ambulatory care(70.0%) appeared to have higher rate than otherwise. In-hospital mortality of CABG inpatients was 2.8%. In addition, 46.4% of the patients received their care in other residence. The angina pectoris(45.6%) was found to be the highest in principle diagnosis, followed by chronic ischemic heart disease(36.9%) and acute myocardial infarction(12.0%). We developed severity-adjusted LOS model using the variables such as gender, age and comorbidity. Comparison of adjusted values in predicted LOS revealed that there were significant variations in LOS by location of hospital, bed size, and whether patients received the care in their residences. The variations of LOS can be explained as the indirect indicator for quality variation of medical process. It is suggested that the severity-adjusted LOS model developed in this study should be utilized as a useful method for benchmarking in hospital and it is necessary that national standard clinical practice guideline should be developed.

• 설비공학논문집
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• 제23권12호
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• pp.782-790
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• 2011

Typical temperature control methods of a cooler for machine tools are hot-gas bypass and compressor variable speed control. The hot-gas bypass system has been widely used to control the cooler temperature in many general industrial fields. On the contrary, the compressor variable speed control is focused on special fields such as aerospace and high precision machine tools which need high precision control. The variable speed control system usually has two control variables such as target temperature and superheat. In other words, the variable speed control system is basically multi-input multi-output(MIMO) system. In spite of MIMO system, the proportional integral derivative(PID) feedback control methodology that based on single-input single-output (SISO) system is generally used for designing the variable speed control system. Therefore, it is inevitable to describe transfer functions for dynamic behaviors of every controlled variables and decide the PID gains with tremendous iteration process. Moreover, the designed PID gains do not provide optimum system performances. To solve these problems, high performance controller design method based on a state space model is suggested in this paper. An optimum controller is designed to minimize both control errors and energy inputs. This method was more simple to describe dynamic behaviors and easier to design the cooler controller which is MIMO system.

• Journal of Preventive Medicine and Public Health
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• 제34권1호
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• pp.21-27
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• 2001

Objectives : To develop a model that will predict the mortality of patients undergoing Coronary Artery Bypass Graft (CABG) and evaluate the perfermance of hospitals. Methods : Data from 564 CABGs peformed in six general hospitals were collected through medical record abstraction by registered nurses. Variables studied involved risk factors determined by severity measures. Risk modeling was performed through logistic repression and validated with cross-validation. The statistical performance of the developed model was evaluated using c-statistic, $R^2$, and Hosmer-Lemeshow statistic. Hospital performance was assessed by severity-adjusted mortalities. Results : The developed model included age, sex, BUN, EKG rhythm, Congestive Heart Failure at admission. acute mental change within 24 hours, and previous angina pectoris history. The c-statistic and $R^2$ were 0.791 and 0.001, respectively. Hosmer-Lemeshow statistic was 10.3(p value=0.2415). One hospital had a significantly higher mortality rate than the average mortality rate, while others were net significantly different. Conclusion : Comparing the quality of service by severity adjusted mortality rates, there were significant differences in hospital performance. The severity adjusted mortality rate of CABG surgery may He an indicator for evaluating hospital performance in Korea.

• 한국정보과학회논문지:시스템및이론
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• 제31권11호
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• pp.635-642
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• 2004

PC 클러스터 상에서 기존의 TCP/IP와 같은 통신 프로토콜의 높은 소프트웨어 오버헤드를 제거하기 위한 노력으로 산업계 표준으로 Virtual Interface Architecture(VIA)가 제안되었다. VIA가 제공하는 통신 방식중, Remote Direct Memory Access(RDMA) 방식은 커널과 리모트 노드의 개입 없이 통신을 가능하게 함으로써 PC 클러스터 시스템에 효율적인 통신 방법을 제공한다. 본 논문에서는 VIA 기반 RDMA 메커니즘을 하드웨어로 구현하였다. 일반적인 송수신방식과 비교하여 본 논문에서 구현한 RDMA 메커니즘은 커널의 개입 없이 무복사 통신을 가능하게 하며, 또한 리모트 노드의 CPU의 사용 없이 통신을 수행할 수 있다. 실험결과, RDMA를 하드웨어 VIA 기반 네트워크 어댑터상에 구현함으로써 최소 12.5${\mu}\textrm{s}$의 지연시간, 최대 95.5MB/s의 대역폭을 얻을 수 있었다. 결과적으로 본 논문에서 구현한 VIA 기반 RDAM 메커니즘은 PC 클러스터 시스템에 효율적인 통신 방법을 제공한다.

• 한국컴퓨터정보학회논문지
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• 제20권8호
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• pp.35-43
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• 2015

Recently, internal information leaks is increasing rapidly by internal employees and authorized outsourcing personnel. In this paper, we propose a method to integrate internal control systems like system access control system and Digital Rights Managements and so on through expansion model of SIEM(Security Information Event Management system). this model performs a analysis step of security event link type and validation process. It develops unit scenarios to react illegal acts for personal information processing system and acts to bypass the internal security system through 5W1H view. It has a feature that derives systematic integration scenarios by integrating unit scenarios. we integrated internal control systems like access control system and Digital Rights Managements and so on through expansion model of Security Information Event Management system to defend leakage of internal information and customer information. We compared existing defense system with the case of the expansion model construction. It shows that expanding SIEM was more effectively.

• 산업경영시스템학회지
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• 제47권2호
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• pp.65-73
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• 2024

This paper presents a path planning optimization model for the engineering units to install obstacles in the shortest time during wartime. In a rapidly changing battlefield environment, engineering units operate various engineering obstacles to fix, bypass, and delay enemy maneuvers, and the success of the operation lies in efficiently planning the obstacle installation path in the shortest time. Existing studies have not reflected the existence of obstacle material storage that should be visited precedence before installing obstacles, and there is a problem that does not fit the reality of the operation in which the installation is continuously carried out on a regional basis. By presenting a Mixed Integrer Programming optimization model reflecting various constraints suitable for the battlefield environment, this study attempted to promote the efficient mission performance of the engineering unit during wartime.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.840-845
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• 2013

본 논문에서는 LC 필터 기술을 기반으로 하는 광대역 주파수 이중 하향변환기(Frequency Double Down-Converter)를 설계 및 제작하였다. 설계한 이중 하향변환기는 저잡음 증폭기, 혼합기, IF 증폭기, LC 필터 등으로 구성되며, DC-Block 커패시터와 RF-Bypass 커패시터로 구성된다. 설계 시에 기존 변환기의 능동소자를 수동소자로 구현하였으며 이에 따라 전력감소 및 저가의 비용을 실현할 수 있었다. 측정 결과, 제작한 주파수 이중 하향변환기는 중심 주파수 63MHz 에서 대역폭 100MHz (13~113MHz)인 광대역을 실현하였으며, 이득은 약 40dB 임을 확인하였다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 제11회 음성통신 및 신호처리 워크샵 논문집 (SCAS 11권 1호)
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• pp.351-357
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• 1994

At least two projects for English-to-Korean translation have been already in action for the last few years, but so far no attention has been paid to the problem of resolving pronominal reference and a default pronoun translation has been considered instead. In this paper we argue that pronous cannot be handled trivially in an English-to-Korean translation and one cannot bypass the task of resolving anaphoric reference if aiming at good and natural translation. In addition, we propose lexical transfer rules for English-to-Korean anaphor translation and outline an anaphora resolution model for an English-to-Korean MT system in operation.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (1)
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• pp.709-711
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• 2003

현재 사용되어지는 컴퓨터 통신 프로토콜(OSI 7 layer reference model)은 구조적인 문제점을 들어내고 있다. 이런 문제점 때문에, 해커들은 수많은 패킷들을 생성시키는 Denial of Service(DoS) 공격과 Distributed Denial of Service(DDoS) 공격을 사용하여 한 호스트나 한 네트워크 자원에 치명적인 악영향을 미친다. 특정한 TCP 포트나 UDP 포트에 공격을 가하는 경우에는 룰 기반의 침입탐지 시스템(IDS)이 탐지 해낼 수 있지만 다른 임의의 포트에 공격을 가하게 되연 IDS는 이것을 탐지하지 못한다. 따라서 우리는 잉의의 포트에 DoS나 DDoS 공격들이 일어났을 때 이 공격들을 탐지할 수 있는 모델을 설계하였다.