• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.241-242
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• 2016

Recently, the interests in safety and prevention from disaster are increasing. In particular, lifeline networks such as water line and sewerage, electricity, gas, and road would be damaged from a disaster. If the lifeline networks do not work in normal, national public service will not properly function. Researches in social network analysis have been conducted for analyzing the interdependency between individuals since 1970s. These network analysis are utilized to investigate a spread of information and disease. However, it is hard to discover the analyzed cases including characteristics of nodes of networks in the area of transportation and disaster. Therefore, this study conducts network analysis of flooded road with flooding scenarios, investigates safe evacuation routes in flooded road network, and suggests efficient approaches for preventing damages from a flooding.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1452-1454
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• 1997

Properties of flashover in polymer insulators are very important under pollution environments. It is necessary to analyse flashover characteristics whether insulators are still safe or not. A lot of precious information can be got out of polluted polymer insulators through leakage current measurement. The behavior of partial arc discharge leads to flashover directly. It is possible to measure partial arc discharge as leakage current pulses analysis. The shape of histogram reflects degree of pollution, wetting and voltage stress level. It can be expressed by Weibull distribution function.

• Korean Journal of Bronchoesophagology
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• v.17 no.1
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• pp.29-34
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• 2011

Traditionally, the main strategy of treatment of the head and neck cancer was en bloc resection including adjacent normal tissues through wide incision. However, the procedures may leave severe functional deficit such as swallowing difficulty, aspiration, and wide neck scar. Therefore, many attempts have been made up to minimize these morbidities. Of them, the minimal invasive approach such as transoral laser microsurgery (TLM) and transoral robot surgery (TORS) have been spolighted as a sensible strategy for organ preservation of the head and neck cancer patients. Results of TLM are equivalent to those obtained by conventional surgery, with considerably less morbidity, less hospital time and better postoperative function. Oncologic results of TLM are equivalent to conventional surgery. TORS are safe, feasible, and promising but oncologic safety is not yet verified. This article covers to current application of TLM and TORS, their advantages and limitations, and future direction.

• Management & Information Systems Review
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• v.6
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• pp.1-19
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• 2001

Partial transactions which use computer networks are formed in the cyberspace due to rapid progress of communication and computer technology. Electronic business transactions have security problems according to the special quality of opening networks, while it can be approached easily by anyone without being tied to time and places through Internets. To revitalize the electronic business transactions, security technology which can establish its security and trust is the prior task and both safe information communication and better information security service offer are essential factors. The method to exchange information through Internets must be made after confirming one another's exact connection in the mutual identity certification to prevent a lot of threat which can occur in the use of password techniques. To satisfy these electronic business transactions, we intend to increase understanding of authentication algorithm provided with authentication function of messages and users as well to plan safety and trust of business information and contents in the electronic business transactions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.172-175
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• 2009

The purpose of this study is to predict the forming limit diagram (FLD) of strain-rate sensitive materials on the basis of the Marciniak and Kuczynski (M-K) theory. The strain-rate effect is taken into consideration in such a way that the stress-strain curves for various strain-rates are inputted into the formulation as point data, not as curve-fitted models such as power function. To solve the nonlinear system of equations derived from the equilibrium and constraints in the groove region and the safe zone, the Newton-Raphson method is used. The theoretical FLDs using four different yield criteria, that are von Mises, Hill (1948), Hill (1979), Logan and Hosford, are compared with the experimental, numerical (FEA) and other theoretical results. A new trial is made where a modified M-K model having n-step grooves is introduced to describe a real localized neck.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.41-55
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• 2015

This study is proposed a new hybrid mount having a moving-magnet type electromagnetic actuator to reduce the vibration transmitted from naval shipboard equipment to the structure of the ship's hull. Optimal design specifications are determined through experimental analysis. The detailed design of the hybrid mount is determined through several design steps with electromagnetic numerical analysis using Maxwell Software(S/W). The hybrid mount that combines a rubber mount and an electromagnetic actuator has a fail-safe function for shock resistance. The mount is fabricated and tested using a universal testing machine to evaluate the design specifications. Finally, numerical simulation of the hybrid mount is performed to confirm control performance and applicability.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.4
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• pp.153-160
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• 2012

This paper is written for the development of boiler combustion air control algorithm of coal-fired power plant by the steps of design, coding and test. The control algorithms were designed in the shape of cascade control for two parts of air master, forced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems under development. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability will be obtained enough to apply to actual site if the total test has been completed in the state that all algorithms were linked mutually. It is expected that the project result will contribute to the safe operation of domestic power plant and the self-reliance of coal-fired power plant control technique.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.238-239
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• 2013

It is a crucial requirement to utilize an economical battery capacity for the wind energy conversion system. In this paper, the optimal BESS capacity is determined for the wind farm whose dispatched power is assigned by the min-max dispatching method. Based on a lifetime cost function that indicates the BESS cost spent to dispatch 1kWh wind energy into grid, the battery capacity can be optimized so as to obtain the minimum system operation cost. Moreover, the battery state of charge (SOC) is also managed to be in a safe operating range to ensure the system undamaged. In order to clarify the proposed optimizing method, a 3MW permanent magnet synchronous generator (PMSG) wind turbine model and real wind speed data measured each minute are investigated.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.3
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• pp.222-229
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• 2005

This paper presents a self-organizing scheme for multi-agent swarm systems based on coupled nonlinear oscillators (CNOs). In this scheme, unicycle robots self-organize to flock and arrange group formation through attractive and repulsive forces among themselves. The main result is the maintenance of flexible and scalable formation. It is also shown how localized distributed controls are utilized throughout group behaviors such as formation and migration. In the paper, the proposed formation ensures safe separation and good cohesion performance among the robots. Several examples show that the proposed method for group formation performs the group behaviors such as reference path following, obstacle avoidance and flocking, and the formation characteristics such as flexibility and scalability, effectively.

• Structural Engineering and Mechanics
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• v.62 no.4
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• pp.487-496
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• 2017

The focus of this study were to investigate patterns between wall pressures and stresses with grain moisture of soybean and rice varieties widespread cultivated in Turkey in order to determine needed designing parameters for structure analysis in silos at filling and discharge. In this study, the wall pressures and stresses were evaluated as a function of moisture contents in the range of 8-14% and 10-14% d.b. The pressures and von Mises stresses affected as significant by the change of grain moisture content. The main cause of pressure and stress drops is changed in bulk density. Therefore is extremely important bulk density and moisture content of the product at the structural design of the silos. 4 mm wall thickness, were determined to be safe for von Mises stresses in both soybean and rice silos is smaller than 188000 kPa.