• Smart Structures and Systems
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• 제12권2호
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• pp.209-233
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• 2013

With an annual growth rate of about 30%, wind energy systems, such as wind turbines, represent one of the fastest growing renewable energy technologies. Continuous structural health monitoring of wind turbines can help improving structural reliability and facilitating optimal decisions with respect to maintenance and operation at minimum associated life-cycle costs. This paper presents an integrated monitoring system that is designed to support structural assessment and life-cycle management of wind turbines. The monitoring system systematically integrates a wide variety of hardware and software modules, including sensors and computer systems for automated data acquisition, data analysis and data archival, a multiagent-based system for self-diagnosis of sensor malfunctions, a model updating and damage detection framework for structural assessment, and a management module for monitoring the structural condition and the operational efficiency of the wind turbine. The monitoring system has been installed on a 500 kW wind turbine located in Germany. Since its initial deployment in 2009, the system automatically collects and processes structural, environmental, and operational wind turbine data. The results demonstrate the potential of the proposed approach not only to ensure continuous safety of the structures, but also to enable cost-efficient maintenance and operation of wind turbines.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2000년도 추계정기학술대회:지능형기술과 CRM
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• pp.289-299
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• 2000

This study provides an application of datamining approach to CQI(Continuous Quality Improvement) using the discharge summary. First, we found a process variation in hospital infection rate by SPC (Statistical Process Control) technique. Second, importance of factors influencing hospital infection was inferred through the decision tree analysis which is a classification method in data-mining approach. The most important factor was surgery followed by comorbidity and length of operation. Comorbidity was further divided into age and principal diagnosis and the length of operation was further divided into age and chief complaint. 24 rules of hospital infection were generated by the decision tree analysis. Of these, 9 rules with predictive prover greater than 50% were suggested as guidelines for hospital infection control. The optimum range of target group in hospital infection control were Identified through the information gain summary. Association rule, which is another kind of datamining method, was performed to analyze the relationship between principal diagnosis and comorbidity. The confidence score, which measures the decree of association, between urinary tract infection and causal bacillus was the highest, followed by the score between postoperative wound disruption find postoperative wound infection. This study demonstrated how datamining approach could be used to provide information to support prospective surveillance of hospital infection. The datamining technique can also be applied to various areas fur CQI using other hospital databases.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.651-651
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• 2015

최근에는 그동안 추진했던 점오염원 중심의 하천수질관리에서 벗어나 비점오염원도 중요한 오염물질로 고려되어 비점오염원 저감을 위한 많은 연구가 진행되고 있는 실정이다. 하지만 기존 비점오염원 저감시설의 설치 사례를 살펴보면 각각의 요소 기술들이 조화를 이루지 못하여 하천의 경관성을 훼손시키고 오염원 차단 및 저감 효과를 상쇄시키는 경우가 대부분이기에 이를 해결할 수 있는 통합적 운전 시스템이 필요하다. 이에 본 연구에서는 기존의 비점오염원 저감시설에 대한 연구를 발전시켜 요소기술의 개별 평가가 아닌 요소 기술들의 통합적 운영에 대한 성능 평가를 실시하고자 한다. 선정된 요소기술은 비점오염원 저감 목적으로 주로 사용되는 저류지, 인공습지, 호안을 선정하여 각 요소기술별 개별 운전과 연계처리 운전을 비교 분석하여 수질정화 능력을 검토하였다.

• The Korean Journal of Pain
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• 제11권1호
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• pp.81-85
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• 1998

Background: Continuous caudal epidural block is a useful method in postoperative pain control after perianal surgery. But caudal epidural block has the potential of developing adverse effects such as urinary retention. The goal of this study is to evaluate the analgesic and adverse effect of bupivacaine with fentanyl through continuous caudal epidural block in relation to the concentration of bupivacaine. Methods: We divided the patients randomly into two groups. For group I(n=25) postoperative pain was controlled by continuous caudal epidural infusion at the rate of 4 ml/hr of 0.0625% bupivacaine with 3 ${\mu}g$/ml fentanyl: group II(n=14), 0.125% bupivacaine with 3 ${\mu}g$/ml fentanyl, respectively, for duration of 48 hours via epidural catheter. We evaluated pain scores with visual analogue scales at 30 mins, 6 hrs, 12 hrs, 24 hrs and 48 hrs after the operation and the incidence of adverse effect, especially urinary retention, for each group. Results: There were no significant differences in the pain score between group I and II. Urinary retention developed in 9 patients(36%) of group I, and 11 patients (78.6%) of group II. Other adverse effects such as pruritus, nausea, vomiting and respiratory depression developed in few patients. Conclusions: While performing continuous caudal epidural block with mixture of bupivacaine and fentanyl after the perianal surgery, we conclude 0.0625% bupivacaine solution is preferable to 0.125% bupivacaine solution because 0.0625% solution resulted in satisfactory analgesia with minimal incidence of adverse effect.

• 한국IT서비스학회지
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• 제20권2호
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• pp.13-31
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• 2021

Recently, delivery app services based on the O2O platform are increasing rapidly. Accordingly, various studies on O2O service have been conducted. Most of the studies are on consumer behavior in O2O services, and few studies on platform vendors have been conducted. Therefore, this study empirically analyzed the factors affecting the vender's intention to continuous use in the O2O delivery app platform service. Based on prior researches, we set the quality characteristics and network characteristics of the O2O platform as independent variables. The quality characteristics of the O2O platform consisted of system quality, information quality, and service quality, and the O2O platform network characteristics consisted of network externality and platform reputation. Perceived value and switching cost were set as mediated variables, and vender's intention to continuous use was set as dependent variables. For empirical analysis, we conducted a survey targeting vendors of O2O delivery app platform service, and conducted frequency analysis, factor analysis, reliability analysis, and regression analysis. As a result of the analysis, the quality characteristics of the O2O platform, such as system quality, information quality, service quality, and O2O platform network characteristics, showed that network externality and platform reputation had a positive effect on perceived value. The perceived value was found to have a positive effect on the switching cost and the intention to continuous use, and the switching cost was found to mediate the perceived value and the intention to continuous use. This study can contribute to the establishment of platform operation strategy as an empirical analysis on the factors that influence the intention of O2O platform vendors to use the platform continuously.

• 한국항해항만학회지
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• 제30권9호
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• pp.749-754
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• 2006

The maritime logistics environment including seaborne trade, shipping and ports is changing rapidly and continuously. Large containerships, mega carriers and global terminal operators try to achieve economies of scale and economies of scope. As a result of the changing environment, the competition between ports to achieve competitiveness is intensive. Port competition among China, Japan and Korea is becoming fiercer, both directly and indirectly, resulting from the increased trade in northeast Asia. Port development projects within each country stimulate more intensive port competition. As a result, overcapacity, fierce price competition and overlapping hinterland problems will be caused in the future. Co-operation for survival is considered as a strategy in order to solve anticipated problems caused by port competition Busan port, for instance, could co-operate with China and Japan as well as with other ports in Korea Terminal operators' expansion through investments including joint-ventures will make connections between ports smoother. At the port authority level, continuous cooperative interchange between countries is indispensable.

• Journal of Power Electronics
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• 제15권3호
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• pp.634-643
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• 2015

This paper presents a high frequency design approach for improving efficiency over a wide load range in the self-driven phase-shifted full-bridge converters for server power systems. In the proposed approach, a detailed ZVS analysis of the lagging leg switches in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM) is presented. The optimum dead time and the determination of the appropriate operation mode are given for high efficiency according to the load conditions. Finally, the optimum operation conditions are defined to achieve a high-efficiency. A laboratory prototype operating at 80 kHz, rated 1 kW (12 V-83.3 A), is built to verify proposed theoretical analysis and evaluations. The experimental results show that the maximum efficiency is achieved as 95% and 83.5% at full load and 5% load conditions, respectively.

• International Journal of Control, Automation, and Systems
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• 제2권1호
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• pp.39-54
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• 2004

We developed an automatic blood pressure control system to maintain the blood pressure of patients at a substantially low level during a surgical operation. The developed system discharges two functions, continuous feedback control of the mean arterial pressure (MAP) by a state-predictive servo controller and risk control based on the inference by fuzzy-like logics and rules using measured data. Twenty-eight clinical applications were made beginning in November 1995, and the effects of the automatic blood pressure control on the operation time and on bleeding were assessed affirmatively by means of Wilcoxon testing. This paper essentially reports the engineering details of the control system.

• 한국축산시설환경학회지
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• 제6권3호
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• pp.169-174
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• 2000

TAO system was applied to treatment of piiggery slurry. In the experiments, the volume of influx was differentiated in four types. The features of operation, evaporation rate, and efficiency of successive treatment were drawn. The results are; 1. During the operation, the inside temperature was maintained at over $60^{\circ}C$ with the highest $70.2^{\circ}C$. 2. The evaporation rate of influx volume was 31.4%. And the evaporation volume of per square meter was $108{\;}\ell/\textrm{m}^2$; slightly different from $120{\;}\ell/\textrm{m}^2$ of batch type. 3. The VFAs was decreased by 95% (from $1,538lmg/{\ell}$ in influx to $72.9mg/{\ell}$ in Efflux). Thus, successive operation of TAO system is considered to be possible.

• 산업경영시스템학회지
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• 제20권41호
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• pp.197-201
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• 1997

Presses are very used in industrial and commercial companies and are often the source of serious accidents occurring during operation. Most of accidents are due to inadequate design of the press machine. This paper presented an experiment which examined eye movement characteristics of the operators in the press operation. Continuous recordings of eye movements were made on five subjects in press operation. It was observed that the subjects stared longer at the die and did not stare at the switch. The eyemovemen patterns per cycle of the subjects were mostly identified as material container $\rightarrow$ die pattern type. The results could be used as basic data to establish a design guideline when manufacturer made the press machine.