• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1431-1441
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• 2017

The Fukushima accident reveals the vulnerability of existing active nuclear power plant (NPP) design against prolonged loss of external electricity events. The passive safety system is considered an attractive alternative to cope with this kind of disaster. Also, the passive safety system enhances both the safety and the economics of NPPs. The adoption of a passive safety system reduces the number of active components and can minimize the construction cost of NPPs. In this paper, reflecting on the experience during the development of the APR+ design in Korea, we propose the concept of an innovative Power Reactor (iPower), which is a kind of passive NPP, to enhance safety in a revolutionary manner. The ultimate goal of iPower is to confirm the feasibility of practically eliminating radioactive material release to the environment in all accident conditions. The representative safety grade passive system includes a passive emergency core cooling system, a passive containment cooling system, and a passive auxiliary feedwater system. Preliminary analysis results show that these concepts are feasible with respect to preventing and/or mitigating the consequences of design base accidents and severe accidents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.57-63
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• 2015

The incidence of fires caused by electrical factors has increased with the growth in domestic electrical consumption. According to the national fire data system of national emergency management agency, electrical fires accounted for 20% of all domestic fires in the last 10 years. Electrical fires are mainly caused by short circuit, leakage current, defect in an electrical equipment, over load, utility fault, etc. The fault current can be several times larger than the nominal current, thereby exceeding the rated current of cable. Consequently, the cable conductor, typically copper wire, heats up to a temperature that ignites surrounding combustibles. This paper describes the transient characteristics of the 0.6/1kV, TFR-8 cable have been investigated, and analyzed under the over current conditions for reduce the risk of electrical fire by experimental and FEM analysis. The experimental and FEM(Finite Element Method) analysis results of temperature and resistance variation according to the over current in copper wires were analyzed. The experimental results coincide well with the FEM analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.172-181
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• 1999

The brakes employed on commercial vehicles must be able to withstand three types of demanding services which are use-emergency stops from high speed, many repeated stops as in a delivery or bus route, and speed control in mountain descents. Two type of friction brakes are in use ; drum breaks and disc brakes. Drum brakes are of the internally expanding type in which two shoes fitted externally with friction material are forced outward against the inside of a rotating drum on the wheel unit. In this case, the Braking power is produced by the friction force between a drum and a lining, and is converted into heat. In this research an unsteady state heat transfer analysis for drum brake system of heavy truck has been performed by ABAQUS/standard code in the case of single-braking and the repeated braking condition. The temperature histories obtained by the finite Element analysis have been compared with the result calculated by the simplified formulation and the result obtained by the experiment of real vehicle conditions.

• Journal of Surface Science and Engineering
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• v.34 no.6
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• pp.575-584
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• 2001

Erosion due to abrasive particles contained in gas streams from boilers has been emerged as a significant problem in the coal fired power plants. Particle erosion accounted for approximately 50% of boiler failures and especially flyash erosion was responsible for 20~30% of emergency boiler shutdowns. Particularly, because of the high ash loading and high velocity, most erosion occurs in the boiler tubes and economiser tube bank where the direction of the gas stream changes to $180^{\circ}$ .In this study, a high temperature particle erosion tester was used to evaluate erosion rate in a simulated environment. The erosion parameters such as erosion temperature, particle impact angle, particle velocity and various particle size were changed. Flyash is the combustion product of the pulverized coal, where size is ranging from 1 to $200\mu\textrm{m}$. Flyash composed of mainly SiO$_2$, $A1_2$$_O3$, and $Fe_2$$O_3$has dense spherical particles and irregular particles containing numerous pores and cavities. From the erosion tests at various conditions, the maximum erosion was experienced at impact angles of $30^{\circ}$ to $60^{\circ}$ In addition, erosion rate increased in proportional to velocity and temperature. And from the observation of the eroded surfaces, it was also concluded that 304 stainless steel was mainly eroded by extrusion-forging at high impact angle ($90^{\circ}$) and by microcutting mechanism at low impact angles ($30^{\circ}$ and $45^{\circ}$).

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.68-76
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• 2007

In general, the braking system of a high speed train has an important role for the safety of the train. To stop safely the train at its pre-decided position, it is necessary to properly combine the various brakes. The train has adopted a combined electrical and mechanical (friction) braking systems. In order to design a good brake system, it is essential for designers to predict the brake performance. In this paper, the braking performance analysis program has been developed and verified by comparing the simulation results with the brake test results of HSR-350x; both results match very well. Also, the brake performances of high speed trains can be predicted by using this program under various conditions.

• Science of Emotion and Sensibility
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• v.6 no.2
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• pp.9-16
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• 2003

This study deals with human reaction speed according to human Physical conditions (head width, breast width, arm extent etc). According to this study, the thickness and extent factor do not affect to human reaction speed, but width factor (head width, breast width). The result of this study can be used to find fitter person for a special job such as emergency condition job, sports man (because you can find a person having a good talent for it before the test). Also, the result of this study can be applied to make CNT (Channel Noise Time) clear The word of CNT is to explain the relation between Channel Noise and Time. (Channel Noise is a kind of noise in the human information transmission channel.).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.536-542
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• 2010

This paper presents an unique approach to scheme a demand response (DR) program in the electricity market from a customer-oriented perspective, which is based on the analytic hierarchy process (AHP). The proposed program has the objective to maintain the system reliability at the emergency period, and it is designed as an incentive-based program (IBP) considering Korea power systems with the cost-based generation pool (CBP). The DR program using AHP could represent the mutual importance degrees of load curtailment criteria from the viewpoint of different load-holders, thus customers' participation in this program is determined by the incentive payments corresponding the specific load curtailment conditions. A test system for the case study is used to demonstrate the usefulness and applicability of the proposed approach, and the load profiles with the proposed DR program and the required incentive payments are obtained. The results show not only the enhancement of system reliability but also the economic benefit within Pareto-improvement.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.192-201
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• 2011

The optimal evaluation algorithms for voltage regulation in the case where new dispersed sources are operated in distribution systems are studied. Handling the interconnection issues for proper voltage managements are often difficult and complicated because professional skills and enormous amounts of data during evaluations are needed. Typical evaluation algorithms mainly depend on human ability and quality of data acquired, which inevitably cause the different results for the same issue. Thus, unfair and subjective evaluations are unavoidable. In order to overcome these problems, we propose reasonable and general algorithms based on the standard model system and proper criterion, which offers fair and objective evaluation in any case. The proposed algorithms are divided into two main themes. One is an optimal algorithm for the voltage control of multiple voltage regulators in order to deliver suitable voltage to as many customers as possible, and the other is a proper evaluation algorithm for the voltage management at normal and emergency conditions. Results from a case study show that proposed methods can be a practical tool for the voltage management in distribution systems including dispersed sources.

• Journal of the Korea Computer Industry Society
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• v.2 no.12
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• pp.1505-1516
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• 2001

The goal of Medical multimedia server is to develop computer hardware and software which would enable electronic access, storage, transmission, and display of patient data and images. Since the current network only provides so called "best-effort" services, it is impossible to satisfy QoS guarantee that is required for real time application services for emergency room, operating room etc. Accordingly, world-wide research is being made for a variety of services to provide QoS. he goal of DiffServ is to offer scalable differentiated service in Internet which are made possible by traffic classification and conditioning only performed at an edge(or a boundary) node. In case DiffServ was deployed in the Medical multimedia network, it is difficult to estimate how the QoS mechanism would affect totally the network performance. Therefore, we need to verify by simulation the design of algorithm which provide a variety of differentiated services. In QoS for Medical multimedia network, a simulator is designed and implemented using OPNET to investigate the performance of DiffServ QoS support mechanism. The developed DiffServ simulator may generate packets according to random, and bursty traffic models in order to incorporate diverse traffic conditions in the Medical multimedia network environment. Based on our simulation results, we confirmed that service differentiation is possible by using the EF(Expedited Forwarding) class in DiffServ networks.

• Journal of Korean Society of Rural Planning
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• v.12 no.2 s.31
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• pp.87-96
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• 2006

The purpose of this study is to increase the utility in terms of the elderly's welfare. The data introduced in this paper were collected by the constructed interview method, and 192 aged interviewees were selected from 4 rural areas: Namhaegun, Uiryeong-gun Imsil-gun and Sunchang-gun. From the descriptive analysis of the data, the results derived are as follows: 1) The financial supports are needed to remodel rural village community facilities as senior centers. 2) It is expected that the facility be a center for the aged people's living in a village, and that have multiple functions of general care service network health care, meal support and making friendship spaces for them. 3) Share housing function is also added to the facility in emergency conditions.