• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술.기술논문발표회
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• pp.43-48
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• 2002

Since the basement building like the communication hole and etc. is built under the ground where it is pressed by the water, the leakage happens due to the dried-shrinking crack, the sinking crack, the creation of the work-joint of the building and etc. caused by the character of the material and construction way of the reinforced concrete building. Especially, a lot of repair for the leakage cannot help but being taken in temporary way without any noticeable countermeasure. Therefore, this kind of repair is socially criticized many times that this is defective construction even if this costs a lot. The fundamental reason of the above mentioned symptoms can be found in the creation of the work-joint caused by the character of the concrete building, the limitation of the physical performance of the existing water-proof and repair material, the limitation of the construction, the limitation of the physical sustaining performance of the concrete building, the limitation(heat-injury, deterioration) of the constancy of the durability caused by aging and etc. Therefore, in this study, we would like to present the better understanding on the water-proof seal relating to the application at the spot and its test evaluation related data since the necessity of the establishment of the quality control standard and the performance testing way on the relevant water-proof seal is rising a lot to regulate the water-proof technology and the leakage repair technology in accordance with the growth of the demand on the facility.

• 해양환경안전학회지
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• 제24권6호
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• pp.825-833
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• 2018

본 연구에서는 LNG 공급계통시스템의 재기화 공정에서 배관 손상으로 인한 누출사고 발생시 LNG 성분 및 누출공의 크기에 따른 연소특성에 대한 피해범위를 산출하고, 피해영향을 해석하였다. LNG 성분에 따른 연소특성을 확인하기 위하여 7곳의 LNG 산지별 위험도를 확인한 결과 산지별 큰 차이를 보이지 않았으나, LNG 구성성분 중 메탄의 함유량이 많을수록 플래시화재 발생범위 및 증기운 폭발에 의한 과압이 발생하는 위험범위 그리고 제트화재 발생에 의한 열 복사량 피해영향이 다른 산지에 비해 비교적 낮음을 알 수 있었다. 또한 배관 누출공의 크기에 따라 누설, 파공, 파괴 3단계에 나누어 위험 범위 및 폭발에 미치는 영향에 대한 연구를 수행하였으며, 플래시화재로 인한 피해영향범위를 계산하고, 이에 따라 LNG 누출시 화재가능 위험범위를 확인했으며, 과압의 영향 및 복사열로 부터의 피해범위를 예측할 수 있었다. 이를 통해 LNG 조성 및 배관 누출공의 크기가 화재 및 폭발에 미치는 영향을 예측할 수 있었다.

• 대한기계학회논문집B
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• 제27권12호
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• pp.1655-1666
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• 2003

It is experimentally well-known that high anisotropies of the turbulent flow field are dominant inside the tip leakage vortex, which is attributable to a substantial proportion of the total loss and constitutes one of the dominant mechanisms of the noise generation. This anisotropic nature of turbulence invalidates the use of the conventional isotropic eddy viscosity turbulence models based on the Boussinesq assumption. In this study, to check whether an anisotropic turbulence model is superior to the isotropic ones or not, the results obtained from the steady-state Reynolds averaged Navier-Stokes simulations based on the RNG k-$\varepsilon$ model and the Reynolds stress model (RSM) are compared with experimental data for two test cases: a linear compressor cascade and a forward-swept axial-flow fan. Through this comparative study of turbulence models, it is clearly shown that the RSM, which can express the production term and body-force term induced by system rotation without introducing any modeling, should be used to predict quantitatively the complex tip leakage flow, especially in the rotating environment.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.135-142
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• 2016

Generally, closed slots are adopted to reduce the water friction loss in both the stator and the rotor of water filling submersible motor due to the special environment of operation. One of the obvious differences between the traditional induction motors and water filling submersible motors is that the submersible motors only need relatively smaller starting torque. This paper aims to analyze the slot leakage reactance of water filling submersible motor during starting transient operation. An improved analytical method which considered the magnetic saturation of the slot bridge and the skin effect of rotor bars is proposed. The slot permeance factor which has a direct impact on the slot leakage reactance is calculated. Then finite element models with different stator slot types are constructed and search coils are introduced to measure the slot flux linkage. Moreover, the starting performances of the models with two typical stator slots are compared and the flux leakage characteristics are obtained. Finally, the results obtained by finite element method are very close to the results obtained by analytical method.

• 인터넷정보학회논문지
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• 제19권3호
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• pp.1-6
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• 2018

Widely used around the world, smartphones contain many features and can store content such as contacts, photos, and videos. Information that can be leaked in proportion to the information that the smartphone can store has also been increased. In recent years, accidents such as personal information leakage have occurred frequently. Personal information leakage is happening in the Android environment, which accounts for more than half of the smartphone operating system market share. Analyzing malicious apps that leak information can tell you how to prevent information leakage. Malicious apps that leak information will send importantinformation to the hacker's (C & C) server, which will use network communication. Malicious apps that are emerging nowadays encrypt and transmit important information through SSL communication. In this case, it is difficult to knowwhat kind of information is exposed to network. Therefore, we suggest a method to analyze malicious apps when leak important information through SSL communication. In this paper, we identify the way malicious apps leak information. And we propose a method for analyzing information leaked by SSL communication. Data before encryption was confirmed in the device through SSL hooking and SSL Strip method.

• KIEAE Journal
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• 제13권3호
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• pp.79-89
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• 2013

The purpose of this study is to evaluate the airtightness performance of New Han-ok and to supply fundamental data for standards establishment. Air leakage testings were accomplished by means of blower door test in 26 bedrooms of 16 Han-oks located in Jeonnam happy villages. Followings are results. 1) Air change per hour at 50 Pa(ACH50) is located on 8.42~78.38. 2) No correlation between ACH50 and volumes, floor area, above grade surface area. 3) The more wood structural elements are exposed, attached spaces, wooden sliding and casement windows, the less airtightness performance. 4) An Airtightness with ACH50/20(NL, Normalized leakage) is located on 0.42~3.92 and building leakage class following F(4%), G(11%, sufficiently leaky, No need mechanical ventilation), H(4%, Need of cost-effective tightening), I(31%), J(50%) by a single-story house the normalized leakage of ASHRAE.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.82-86
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• 2004

This research is about the result of leakage current waveform about the situation of surface leakage current and environmental changes(Salt fog, clean fog and rain) by EPDM polymer insulators' amount of salt. The researcher presents the result of changing about fundamental harmonic, 3rd harmonic and 5th harmonic from starting point of supplying power to flashover. In this study, researched environmental affects (clean fog, salt fog and rain) about surface aging of polymer insulators and used frequency spectrum of leakage current waveform to develop the diagnostic technique of surface aging. When amount of salt contents changed, surface aging stage and the degree of aging (distortion factor) about 3rd and 5th harmonic waveform on low frequency harmonic wave. The distortion factor which is harmonic percentage about basic harmonic is important pointer to evaluate the surface condition of polymer insulators.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.65-73
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• 2015

The hydrofluoric acid (HF) leakage accident occurred on September 2012 in Gumi, Korea affected the surrounding soils and plants. In this study, we investigated fluoride migration in Gumi area through geochemical properties of soil-liquid phase (pore water F and water-soluble F). The concentrations of porewater F and water-soluble F were obtained from N.D (Not detected) to 9.79 mg/L and from 0.001 to 21.4 mg/L, respectively. F in pore water seemed to be affected by artificial and natural origin, and PHREEQC results implied that fluorite is F control factor. F concentrations of soil and soil-liquid phase did not exceed concern level of regulatory criteria and showed similar trends compared by previous studies. Therefore, F contents remained in the soil and soil-liquid phase were considered to be not affected by HF leakage accident.

• 디지털산업정보학회논문지
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• 제15권2호
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• pp.43-52
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• 2019

The recent technological developments of smart devices, multiple services are provided to enhance the users' quality of life including smart city, smart energy, smart car, smart healthcare, smart home, and so on. Academia and industries try to provide the users with convenient services upon seamless technological research and developments. Also, whenever and wherever a variety of services can be used without any limitation on the place and time upon connecting with different types of devices. However, security weaknesses due to integrations of multiple technological elements have been detected resulting in the leakage of user information, account hacking, and privacy leakage, threats to people's lives by device operation have been raised. In this paper, safer communication framework is suggested by device control and user authentication in the mobile network environment. After implementations of registration and authentication processes by users and devices, safe communication protocol is designed based on this. Also, renewal process is designed according to the safe control of the device. In the performance evaluation, safety was analyzed on the attack of protocol change weakness occurred in the existing system, service halt, data leakage, illegal operation control of message, and so on, which confirmed the enhanced speed approximately by 8% and 23% in the communication and verification parts, respectively, compared to the existing system.

• 한국가스학회지
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• 제27권3호
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• pp.72-76
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• 2023

도시가스 사용시설 중 은폐배관에 점검구를 대신하여 누출점검용 가스계량기를 사용하는 사례가 증가하고 있다. 이 계량기가 설치되어 있는 일부 세대 중 실제 가스누출이 없는 환경에서 보일러의 특수한 사용 패턴에 따라 누출 알람 경보가 지속적으로 발생되었다. 실제 가스 누출을 감지하는 본연의 기능을 발휘하지 못하는 실정이다. 이러한 문제점에 착안하여 본 연구에서는 보일러의 특수한 가스 사용 패턴에 따라 누출점검용 가스 계량기가 누출 알람을 발생시키는 조건을 분석하고, 실제 가스 누출이 있는 경우에만 계량기에서 알람을 발생 할 수 있는 설정값을 모색해 보았다. 이를 통해 알람의 오작동으로 인한 시민의 가스 사용에 대한 불안감을 해소함과 동시에 누출되고 있는 가스를 포착할 수 있는 계량기 본연의 기능을 수행할 수 있도록 하고자 한다.