• 한국건설관리학회논문집
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• 제10권1호
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• pp.78-90
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• 2009

오늘날 고속도로 운영은 IT를 기반으로 하는 복잡한 Digital Infrastructure이다. 이러한 IT의 활용은 점점 많아지고 있는데, 예측 불가능한 운영위험이 발생할 경우 IT의 편리함만큼이나 피해가 예상외로 커질 수 있다. 고속도로 운영 위험은 도로의 운영이 중단되어 도로이용자들이 서비스를 제공받지 못하는 것이다. 운영위험은 예상하지 못한 과다한 운영관리비 및 유지관리비의 발생으로 계획된 운영비를 초과하는 것이며, 운영수입의 손실을 가져온다. 그 결과 이용자 안전의 위험과 운영자의 부실을 초래하게 되는데, 기존의 연구는 이를 추정할 수 있는 방법에 대한 연구가 미흡한 실정이다. 따라서 본 연구에서는 디지털화된 고속도로에서 대규모 정전사태가 발생할 경우 추가로 발생되는 운영비 항목을 구체적으로 제시하고 각 항목에 대한 예상 가능한 위험비용을 시뮬레이션 추정을 하고자 하였다. 이를 근거로 하여 운영위험을 방지하기 위한 비용예산과 운영계획 측면에서 방안을 제시하고자 하며, 향후 운영의 건전성을 확보할 수 있는 기초자료로 활용을 도모코자 한다.

• 한국추진공학회지
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• 제22권6호
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• pp.11-18
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• 2018

펄스 데토네이션 엔진 (PDE는) 추진기관으로서 의미 있는 추력을 얻기 위해 100 Hz 이상의 높은 작동 주파수를 요구한다. 따라서 PDE는 높은 작동 주파수에서 정확하게 작동하는 점화 회로 필요로 한다. 이번 논문에서는 교류와 직류 전원을 이용하는 두 종류의 점화 회로를 설계하여 비교하였다. 두 회로는 16.66 에서 100.00 Hz 작동 주파수에서 입력 신호와 변압기의 1 차 코일에 인가되는 전압 변화를 측정하여 시험하였다. 실험 결과 직류 전원의 회로의 경우 증가된 작동 주파수에서 최대 5.15%의 작동 주파수 오차를 보였으나 교류 전원의 회로의 경우 33.33 Hz 이상부터는 거의 맞지 않는 결과를 보였다. 이를 통해 고주파 작동의 PDE에서는 직류 전원의 점화 회로가 선호됨을 확인하였다.

• Journal of Korean Biological Nursing Science
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• 제23권1호
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• pp.43-54
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• 2021

Purpose: This study aimed to identify the factors influencing infection-related characteristics and patient safety culture on awareness of blood-borne infection prevention between operating room nurses and general ward nurses. Methods: Participants were 198 nurses(operating room nurses 98 and general ward nurses: 100) working at three general hospitals and three university hospitals in three cities. Data were collected using a structured questionnaire from September 11 to October 14, 2020. Data were analyzed using descriptive statistics, t-tests, ANOVA, Pearson's correlation coefficient, and multiple regression with IBM SPSS/WIN 26.0 program. Results: Typically, 39.8% of nurses in the operating room and 24.0% of ward nurses experienced injuries such as needles and sharp instruments used by the patient. The awareness of patient safety culture was identified to be higher for the ward nurses. Factors influencing the awareness of blood-borne infection prevention in operating room nurses were patient safety culture and wearing protective equipment for infection prevention while nursing infected patients. Moreover, the explanatory power of these variables was 19.4%. In general ward nurses, the patient safety culture was identified as a significant predictor, which accounted for 16.5% of awareness of blood-borne infection prevention. Conclusion: To prevent hospital infection, a strategy is needed to improve the level of awareness of blood-borne infection prevention and patient safety culture of operating room nurses. To this end, the difference in infection-related characteristics and influencing factors between the operating room nurses and the general ward nurses should be considered and planned.

• 한국안전학회지
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• 제38권5호
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• pp.1-7
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• 2023

This study analyzes the operational characteristics of 311 aged and non-aged residual current circuit breakers (RCCBs) in low-voltage consumer contexts. It investigates the influence of external temperature and harmonics based on the rated current multiples. To simulate temperature variations, a convectional oven was used around the circuit breakers. Additionally, the generation of harmonic reference signals and data measurement for overcurrent experiments were conducted using NI SCXI, myDAQ, and LabVIEW. An observation revealed that as the ambient temperature increased, the operating time of RCCBs decreased in the time delay region. This was attributed to the faster response or bending of the bimetal, which is the tripping element. However, aged RCCBs encountered challenges with tripping outside the protective curve. The operating time of the circuit breakers exhibited an acceleration influenced by the order and content of harmonic currents, potentially leading to malfunctions. Aged RCCBs demonstrated faster operating times than their non-aged counterparts. However, the difference in operating time varied based on the manufacturer's and operating environment of the RCCBs. Frequent malfunctions of RCCBs can result in power outages. In cases where these circuit breakers fail to operate, they can lead to secondary damages, including electrical fires and shocks. Consequently, it is imperative to consider the operating environment of RCCBs and provide appropriate replacement cycles to mitigate these risks.

• 산업경영시스템학회지
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• 제23권57호
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• pp.41-49
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• 2000

This paper investigates the relation between operating performance and initial underpricing of companies that go public. A significant decline in operating performance subsequent to the initial public offering(IPO) is found. Additionally there is a significant positive relation between post-IPO operating performance and the level of initial underpricing.

• 전기학회논문지
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• 제62권4호
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• pp.444-450
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• 2013

This paper presents the criteria for setting the dynamic operating mode of BESS(Battery Energy Storage System) in the bulk power systems. ESS has been expected to improve the degraded dynamic performance of the power system with high penetration of the renewable resources. While ESS is controlled in steady state or dynamic operating mode for its better effectiveness depending on the operating conditions of power systems, the criteria for setting the dynamic operating mode for the transient period needs to be robust enough to cover all the different conditions. The proposed criteria consider the varying conditions and the operating practices of the bulk power systems.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.315-317
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• 2002

The value of I$_{c}$(critical current) in HTS (High Temperature Superconducting) tape has a great influence on B(equation omitted) (magnetic field amplitude applied perpendicular to the tape surface). Therefore, I$_{c}$ of HTS magnet is determined by not only operating temperature but also the B(equation omitted). In shape design of field coil for the HTS motor, a method to reduce the B(equation omitted) and to determine operating current should be considered in order to optimal design. On the basis of the magnetic field analysis, this paper deals with various field coil shape to obtain operating current of HTS motor by using analytical method. And also this paper discusses the operating current of 100hp class HTS motor by using I$_{c}$-B(equation omitted) curve.curve.

• 대한기계학회논문집A
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• 제27권5호
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• pp.789-797
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• 2003

In the procedure of the hydraulic control system design, a linearized approximate equation described by the first order terms of Taylor series has been widely used. Such a linearized equation is effective just near the operating point, However, pressure and flowrate in actual hydraulic systems are usually not confined near an operating point. This study suggests a new linearized flow equation for a servovalve as a modified form of the conventional linearized flow equation. Subsequently, a procedure to determine effective operating point for the new linearized equation is proposed. From the evaluations of time responses and frequency responses obtained from simulations for a hydraulic control system, the effectiveness of the new linearized equation and the procedure to determine effective operating point is confirmed.

• Korean Journal of Hydrosciences
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• 제4권
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• pp.65-79
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• 1993

Selection of the best operating rule among a set of alternatives for a multipurpose reservoir system operation requires to evaluate many minor criteria in addition to the major objectives assessed to the system. These problems are sufficiently complex and difficult that they are beyond heuristic decision rules and experiences in case several noncommensurable multiple criteria are included in the evaluation. With the assistance of multicriterion decision analysis techniques, it is possible to select the best one among various alternatives by systematically comparing and ranking the alternatives with respect to the criteria of choice. Evaluation criteria for multipurpose reservoir system operating rules were identified and defined, and the multicriterion decision analysis techniques were applied to evaluate the four existing operating rules of the Chungju multipurpose project according to the identified nine multiple criteria. The application results show that the methodology is very efficient to select the best operation alternative among a finite number of operating rules with many evaluation criteria for a large-scale reservoir system operation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.699-702
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• 2006

Noise Path Analysis is commonly used method to analysis noise transmission characteristics of a system. To analysis transfer paths of a system, it is necessary to know operating forces at each transfer path. The method to find out operating forces is divided into two methods. The one is a direct method which measures operating forces directly and the other is an indirect method which estimates operating forces mathematically. However, the indirect method is more commonly used because of the difficulty of measurement. This paper is focused on the indirect method and air-borne noise of a vehicle. Noise Path Analysis for Air-Borne Noise is applied to a real vehicle.