• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.513-520
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• 2003

Service restoration is an emergency control in distribution constrol centers to restore out-of-service area as soon as possible when a fault occurs in distribution networks. therefore, it requires fast computation time and high quality solutions for load balancing. In this paper. a load balance index and heuristic guided best-first search are proposed for these problem. The proposed algorithm consists of two parts. One is to set up a decision tree to represent the various switching operations available. Another is to identify the most effective the set of switches using proposed search technique and a load balance index. Test results on the KEPCO's 108 bus distribution system show that the performance is efficient and robust.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.470-478
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• 2016

This study focused on the emergency evacuation guidelines considering the behaviors of people with disabilities in Korea. For these purposes, this study reviewed the movement behaviors of people with disability and the treatment characteristics of emergency and hazards in United States. The results are as follows. First, it is necessary to suggest establishment requirements and building design guidelines considering the behaviors of inhabitants and the occupant load in social welfare facility for people with disabilities. Second, it is important to establish disaster preparedness and evacuation planning in emergency and hazards reflecting the movement behaviors of people with disabilities in national organizations and institutions on disability. Third, periodical emergency and fire drills are necessary for people with disabilities and should be managed considering the impaired prototypes, evacuation aids and service animals.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.5
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• pp.474-484
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• 2018

Objective: The time to positivity (TTP) of blood culture reflects bacterial load and has been reported to be associated with outcome in bloodstream infections. This study was performed to evaluate the relationship between the TTP of blood culture and the mortality rates associated with sepsis and septic shock according to the site of infection. Methods: We performed a retrospective cohort study on patients with sepsis and septic shock. The rates of blood culture positivity and mortality as well as the relationship between the TTP and 28-day mortality rate were compared among patients with different sites of infection, such as the lungs, abdomen, urogenital tract, and other sites. Results: A total of 2,668 patients were included, and the overall mortality rate was 21.6%. The rates of blood culture positivity and mortality were different among the different infection sites. There was no relationship between the TTP and mortality rates of total, lung, and urogenital infections. Patients with abdominal infections showed a negative correlation between the TTP and 28-day mortality rate. In patients with abdominal infections, a TTP<20 hours was independently associated with 28-day mortality compared with patients with negative blood culture (hazard ratio, 1.73; 95% confidence interval, 1.16-2.58). However, there was no difference in mortality rates of patients with a $TTP{\geq}20$ hours and a negative blood culture. Conclusion: The shorter TTP in patients with abdominal infections in sepsis and septic shock was associated with a higher 28-day mortality rate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.79-86
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• 2014

This paper describes an integrity evaluation method for emergency diesel generator(EDG) and rotor part of EDG. EDG is a very important equipment in the nuclear power plant(NPP). EDG supplies electricity to the safety-related equipments for the safety shut down of NPP in an emergency situation of earthquake. The safety of the rotor part of EDG is also important during seismic impact from earthquake. The finite element modelling of the EDG including rotor part was constructed. The modal analysis of EDG was firstly performed. The first natural frequency was calculated and revealed higher than the cutoff frequency of seismic spectrum. Then the stress analysis was done to compare with the allowable stress. The safety of the rotor part was investigated by the finite element analysis of the rotor and journal bearing interaction to find film thickness and critical speed. The seismic load was applied to rotor part in a manner that the load was a weighted static load. Analysis results showed that the maximum stress was within the range of allowable stress and the film thickness is larger than the permissible minimum thickness, and the critical speed was out of the operating speed. Hence, the structural and dynamic integrity of EDG could be confirmed by the numerical analysis method used in this paper. However, dynamic analysis of a rotating rotor and supporting bearing with the seismic impact needs to be investigated in a more rigorous method since the seismic load to the rotating part complicates the behavior of rotating system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.70-79
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• 2015

In this paper, enhanced stand-alone operation and development of Matlab/Simulink model of emergency diesel based hybrid energy system is presented. Simulations based on the remote community or islands were performed for PV-diesel-battery hybrid system. Modeling of PV-diesel-battery integrated system is done to perform under the solar radiation and load conditions on Matlab/Simulink platform. The models of diesel generator unit, battery energy storage system, PV and frequency-power control are developed and simulation studies have been carried out under various conditions using Matlab/Simulink and SimPowerSystem. It is demonstrated that the proposed system can provide reliable and good quality power to the customers in diesel synchronous generator-based hybrid energy systems.

• International Journal of Quality Innovation
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• v.9 no.3
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• pp.1-14
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• 2008

Patient satisfaction with the Emergency Department(ED) in a hospital is related to the length of stay, and especially to the amount of waiting time for medical treatments. ED overcrowding decreases quality and efficiency, therefore affecting hospitals' profitability. This paper presents a forecasting and simulation model for resource management of the ED at Moses H. Cone Memorial Hospital. A linear regression forecasting model is proposed to predict the number of ED patient arrivals, and then a simulation model is provided to estimate the length of stay of ED patients, system throughput, and the utilization of resources such as triage nurses, patient beds, registered nurses, and medical doctors. The near future load level of each resource is presented using the proposed models.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.155-156
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• 2015

Recently, electricity consumption has rapidly increased along with economic growth. The operating strategy using emergency generator is aimed, to resolve a demand response management. For strategy of peak shedding using emergency generator, it is essential to introduce the fast transfer switching device. One of the most effective solutions is to use a static transfer switch (STS) based on thyristor. However, the characteristic of natural commutated SCR thyristor should anticipate short duration voltage sag. STS system thus requires more than a quarter cycle to successfully complete transfer process. This paper proposes the operation scheme of the STS system using the forced-commutation technique to mitigate instantaneous voltage sag during peak transfer process. Proposed STS system improved turn-off characteristic thus accomplishes the peak load shedding satisfied power quality. Performance of the proposed STS system is evaluated using electromagnetic transient program (EMTP) to confirm the effectiveness.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.293-298
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• 2005

The following is final report for governor upgrade for PWR NPP safety related EDG Kori NPP No.2 Unit. The upgraded system includes more beneficial function like as "Slow start with starting ramp", "Generator load sensing & control capability" and "Emergency ramp during slow start". This paper show functional operation of slow start regime according to NRC regulatory guide which guide regulation to NPP safety related environment.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.34-37
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• 2003

The frequency of power system will change when the load-generation equilibrium is disturbed. Insufficiency of generation from the imbalance between load and generation decreases the power system frequency. In case of the severe emergency, the under frequency load shedding scheme is applied for the power system defense plan. In this paper, we analyzed the dynamic characteristics of under frequency load shedding using new Transient Security Assessment Tool ; TSAT. We applied the actual UFLS scheme to these studies and considered the possible contingency.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.1
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• pp.7-12
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• 1983

When emergency lighting using a D.C. source is needed, we select the fluorescent lamp that has higher efficiency than that of an incandescene lamp. This paper deals with a series inverter for a fluorescent lamp load, which has high frequency output characteristics. First, the appropriate operating frequency is determined and second, the optimum value of circuit elements is determined in consideration of several important conditions. The results obtained by experimentations are represented.