• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.395-400
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• 2002

Epoxy coating and sealing used in nuclear plants for the protection of radiation degrades with aging and hazardous atmosphere. In order to evaluate the degradation of the epoxy, dependence of the acoustic impedance on the change of mechanical properties has been used. Unlike metals, the surface of the epoxy coating on a concrete liner is so wavy that the acoustic impedance is difficult to measure by using the reflectivity of the ultrasound on the interface surface because of the irregular reflection and propagation from the epoxy surface. SA(simulated annealing) algorithm is applied to calculate the acoustic impedance using a reflection wave from the rough epoxy surface. The surface waviness and acoustic impedance are taken into account and determined by SA method to evaluate the state of degradation quantitatively.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.33-38
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• 2016

Constitution declares culture is area that without any interference from the state space, and so creates each person creative energy. It is a typical movie in culture. The film will be referred to as an important expression form as well as high value-added industries of cultural creativity of ethnic communities. Intervention of the state is necessary that by competing mechanisms of diverse opinions and ideas caused harm. State intervention is only to be operated at a minimum. The vulgarity causes young people have impulsive tendencies and affects adults adversely on on issues, regulation is possible for children and youth protection. This paper aims to suggest a new legislative measure about the legal principles of vulgarity regulation to solve this kind of problem efficiently. Some standard allowed vulgarity regulation on the principles of control.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.429-432
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• 2006

In this study a board was made with good fireproof materials of which test was conducted according to the fireproof test for KS F 2257 construction members, and the temperature in coated steel which has a possibility to explode with concrete surface was measured. It is not appropriate to use normal mortar or mortar covering mixed with P.P. fiber to take a measure to prevent the explosive splalling of high-strength concrete. To finalize an Al-Si (aluminosilicates) board-requires over 30mm in thickness at the minimum for the required fire resistance performance and explosion prevention.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.375-376
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• 2008

Recently the increase of natural disaster and man-made disaster, newly emerging infectious diseases and bioterrorism attack changed the world in many aspects. So the Ministry of Health and Welfare and other related agencies are trying to solve the problems with disasters. We discussed these problems in the following eleven categories. (1) emergency medicine (2) communicable disease control, (3) food safety control, (4) public facilities safety, (5) social welfare facilities safety, (6) bioterrorism control, (7) geriatric health care, (8) insurance support, (9) overseas disaster victim support, (10) national organization protection, (11) fire fighter safety in forest fire. Through the reviews on the various kinds of disaster, we proposed the disaster control measure for the near future.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.182-186
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• 2004

When most of existing instant messengers log on server, they transmit to sever in encoding password to RC5. but RC5 don't be secured because it has been known many of password cracking tools. Also, messengers don't have any protection on the transmitted information with communicating two hosts since loging on, endangering the privacy of the user. As a counter measure, messengers need to provide security service including message encryption. In this paper, we designed a key exchange method of password representing fast, effective and high security degree, using ECC(Elliptic Curve Cryptography) that being known the very stronger than another public key cryptography with same key size. To effectively improve data transmission and its security using IPSec protocol between users, tunnel mode is introduced. Tunnel mode transmits Host-to-Host data through virtual pipelines on the Internet.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.731-734
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• 2003

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential, amplitude of stray current, point of source of stray current and so. In this paper, results of development about data logger apparatus for measurement stray current of subway and power line are presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3950-3964
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• 2017

With the increasing popularity of 3D technology such as 3D printing, 3D modeling, etc., there is a growing need to search for similar models on the internet. Matching non-rigid shapes has become an active research field in computer graphics. In this paper, we present an efficient and effective non-rigid model retrieval method based on topological structure and local volume. The integral geodesic distances are first calculated for each vertex on a mesh to construct the topological structure. Next, each node on the topological structure is assigned a local volume that is calculated using the shape diameter function (SDF). Finally, we utilize the Hungarian algorithm to measure similarity between two non-rigid models. Experimental results on the latest benchmark (SHREC' 15 Non-rigid 3D Shape Retrieval) demonstrate that our method works well compared to the state-of-the-art.

• Fire Science and Engineering
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• v.8 no.1
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• pp.3-8
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• 1994

A new test system was established to measure the flame extinguishing concentration of Halon alternatives. The main characteristic of this system is to use the solid paraffin with a wick instead of liquid fuel, such as n-Heptane. Our results showed that the extinguishing concentration of compounds was lower than that of other existing data, but the trend was consistent with others. The flame extinguishing concentration of all tested compounds were not almost effected by gas flow velocity. The system produces good reliable data with a minimum error for measuring the flame extinguishing concentration. Therefore our new system can be utilized as a standard equipment to evaluate Halon alternatives.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.15-21
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• 2020

Industrial facilities need design to predict and reduce noise from design to prevent and reduce noise. The purpose of this study is to predict worker's environment and evaluate safety by analyzing noise inside underground blower room and air compressor room with fluid machinery in waste facility. This waste incineration facility was analyzed based on the ground floor, ground floor blower chamber, and air compressor chamber. The results of SPL(Sound Pressure Level) analysis at 1.5m away, which are frequently used to measure the SPL as a noise source, are as follows. SPL of basement level: 46.80[dB], SPL of ground layer: 48.57[dB]. As a result, it was expected that the noise level would be considerably lower than the 8 hours 50[dB] noise exposure per day.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.47-55
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• 2020

This study analyzed ignition probability about Lithium-polymer batteries of what variously were being produced wearable devices recently. The study analyzed ignition probability by PCM(Protection Circuit Module) operating state and overcharged, over-discharged, exposed to high temperatures of Lithium polymer batteries, analyzing wearable devices on the market. Then it classified experimental results to implement analysis comparison about weight, X-ray imaging, battery decomposition. With these experiments, the study analyzed combustion-possibility and fire patterns. These statistics will be used to measure and verify the cause of a fire when identify wearable devices using Lithium-polymer batteries.