• 한국산업보건학회지
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• 제25권1호
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• pp.82-88
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• 2015

Objectives: This study is designed to analyze the penetration performance into ceiling materials containing asbestos of scattering prevention agents and investigate the change in penetration depth and viscosity according to the dilution rate of anti-scattering agents diluted with distilled water. Methods: Five different types of scattering prevention agents were spread on plate-type asbestos ceiling materials. The penetration depth of each coated ceiling material was measured by energy dispersive spectroscopy (EDS) analysis, based on X-ray fluorescence (XRF) results of the non-coated ceiling materials. Test equipment installed the ceiling materials and 60 minutes were collected at a flow rate of $10{\ell}/min$ at a filter of 25 mm. Results: An EDS analysis of the cross-section of ceiling materials constructed with a scattering prevention agent revealed that potassium is detected in the process of penetrating hardener solidification and this element could be an indicator for infiltration. When anti-scattering agents with different viscosities were constructed and the penetration depth was analyzed by potassium detection assessment using EDS, the depth results with viscosities of 5.0, 2.5, and 1.9 cP were 98.5, 103, and $147{\mu}m$, respectively. Penetration performance improved with decrease in viscosity. Conclusions: For asbestos ceiling materials, it is concluded that a higher dilution rate of the scattering prevention agent leads to lower viscosity, and hence a deeper penetration depth from $156{\mu}m$ to 3 mm. The asbestos anti-scattering properties according to the penetration depth will be confirmed through further study.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.230-233
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• 2014

최근 보안 위협과 위험이 매우 빠른 속도로 변화하고 있어, 다각화 되는 공격기법에 대응하기 위한 필수 조건으로 기업 및 기관에서 모의 침투 테스트를 진행하고 있다. 침투 테스트(Penetration Test, PenTest)는 합법적이고 승인된 시도로 컴퓨터 시스템을 더 안전하게 하기 위해 시스템의 취약점을 찾아내고, 찾아낸 취약점에 대해 공격을 시도하는 것이다. 모의 해킹 테스트와 같은 용어로 사용되고 있으며 취약점이 어떻게 악용될 수 있는지 공격을 시도하여 보여준다. 한편, 현재 많은 보안업체에서 다양한 방법 및 절차로 침투 테스트를 수행하고 있으나, 실제로 이러한 테스트의 강도와 신뢰성에 대한 평가는 아직 이루어지지 않고 있다. 따라서, 본 연구에서는 이와 같은 침투 테스트에 대하여 검증되고 신뢰할 수 있는 평가 방법을 제시한다. 본 연구에서 제시한 침투 테스트 평가 정보를 활용하여 보다 신뢰할 수 있는 평가 결과를 얻을 수 있고, 결과적으로 효율적인 침투 테스트가 가능할 것으로 기대된다.

• 비파괴검사학회지
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• 제4권2호
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• pp.7-14
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• 1985

An experiment to investigate the rate of change of phase angle of eddy current output signal caused by outer surface defect of nonferromagnetic tube by variation of standard depth of penetration and variation of percent of tube wall penetration was carried out. The results of the experiment show that the phase angle of defect signal is increased with decreasing the standard depth of penetration or the depth of defect. The results also show that the phase angle is decreased with increasing the skin effect of eddy current, and that the resolution is decreased with decreasing the depth of defect.

• Computers and Concrete
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• 제21권2호
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• pp.111-116
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• 2018

Establishment of test methods to assess the fresh properties of self-compacting concrete (SCC) are required to ensure the homogeneity in fresh and hardened states. This paper discusses the suitability of a simple test method for assessing the slump flow and stability of SCC by testing on self-compacting mortar (SCM) fraction. The proposed test method aims at investigating slump flow diameter test and sieve stability test of SCC by testing SCM fraction with a plunger penetration apparatus. A central composite modeling design was performed to evaluate the effects of water/cement ratio (W/C), superplasticizer dosage (SP) and powder marble content (MP) on slump flow diameter, stability and plunger penetration test of fresh SCC. The responses of the derived statistical models are slump flow (Sf), sieve stability (S) and plunger penetration (P). Relationships obtained in this study show acceptable correlations between plunger penetration test value and slump flow diameter test results and stability. It should note that the developed relationships are very useful to predict slump flow diameter and stability of studied SCC mixtures by carrying out a simple plunger penetration test on its mortar, which can save labour and time in laboratory experiments.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.611-622
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• 2007

In the design and construction of the coastal/offshore structures, it is very important to evaluate the geotechnical characteristics of marine soils, which support the structures. Although the offshore site investigation is much more difficult than onshore, safe and precise jobs have not been accomplished in Korea because of the insufficiency of the test equipments especially for the site with deep water depth. The main objective of this study is to develop a new type of marine cone penetration testing(CPT) system, which can be utilized to even deep sea and high depth of soil layer. The system is one of seabed types and employs the conventional cone, which shows more reliable results than miniature cone. The most important parts of the marine CPT including continuous rod system, cone penetration system with wheel drive, automatic cone rod assembly/dissembly system etc., were designed and manufactured. Some tests to verify the developed marine CPT system were performed at both onshore and offshore sites as well as mechanical test in laboratory. The test results show the consistent and promising performance of the new equipment, and thereafter the system would be applicable to various sites with practical/economical advantages.

• 지질공학
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• 제31권4호
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• pp.541-547
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• 2021

비탈면의 유실, 붕락사고 등 비탈면에 대한 안정성을 파악하기 위해서 지층의 구성상태, 역학적 특성 등의 지반정보 파악이 필요하다. 이러한 지반정보를 파악하기 위해서 일반적으로 표준관입시험(SPT) 및 콘 관입시험 등이 널리 이용되고 있다. 대부분이 급경사로 이루어지고 진입로가 없는 비탈면에 대한 접근성 문제로 표준관입시험이 널리 활용되지 못하고 있다. 이러한 단점을 보완할 수 있는 있는 휴대용 장비인 Drop Cone Penetrometer(DCP)를 이용한 조사도 여러 가지 문제로 제한적으로 사용되고 있다. 따라서 본 연구에서는 비탈면 현장접근이 용이한 휴대용 시추기와 동적콘관입시험 모듈을 개발하고, 개발된 동적콘관입시험기를 이용한 결과와 동일 현장에서 수행한 표준관입시험값과 상관성을 분석하였다. 에너지전단율로 보정된 동적콘관입시험과 표준관입시험간의 상관식은 N_d' = 3.13 N'으로 나타났다.

• Nuclear Engineering and Technology
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• 제36권4호
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• pp.346-356
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• 2004

14 Pressurized Water Reactors (PWR) in Korea use a remote monitoring system (RMS), which have been used in Korea since 1998. A Memorandum of Understanding on Remote Monitoring, based on Enhanced Cooperation on PWRs, was signed at the 10th Safeguards Review Meeting in October 2001 between the International Atomic Energy Agency (IAEA) and Ministry Of Science and Technology (MOST). Thereafter, all PWR power plants applied for remote monitoring systems. However, the existing method is high cost (involving expensive telephone costs). So, it was eventually applied to an Internet system for Remote Monitoring. According to the Internet-based Virtual Private Network (VPN) applied to Remote Monitoring, the Korea Atomic Energy Research Institute (KAERI) came to an agreement with the IAEA, using a Member State Support Program (MSSP). Phase I is a Lab test. Phase II is to apply it to a target power plant. Phase III is to apply it to all the power plants. This paper reports on the penetration testing of Phase I. Phase I involved both domestic testing and international testing. The target of the testing consisted of a Surveillance Digital Integrated System (SDIS) Server, IAEA Server and TCNC (Technology Center for Nuclear Control) Server. In each system, Virtual Private Network (VPN) system hardware was installed. The penetration of the three systems and the three VPNs was tested. The domestic test involved two hacking scenarios: hacking from the outside and hacking from the inside. The international test involved one scenario from the outside. The results of tests demonstrated that the VPN hardware provided a good defense against hacking. We verified that there was no invasion of the system (SDIS Server and VPN; TCNC Server and VPN; and IAEA Server and VPN) via penetration testing.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.163-170
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• 2010

Today, In-Situ testing for measureing geotechnical characterization are divided by Cone Penetration Test, Standard Penetration Test and Dilatometer Test, and will vary depending on soil conditions have been applied (Korea Geotechnical Engineering, 2006). However, these methods can be applied on sand or soft clay soil. Now, many studies are progressing for evaluating the stiffness characteristic of rocks and IGM. and Nam moon suk(2006) did Texas Cone Penetrometer Test for designing field penetration pile intruded at rocks and IGM. but, reliability of Texas Cone Penetration Test has confidence limits because TCPT is testing in Texas centrally, and energy dose not measure Woojin Lee, etc. (1998) did calculate Standard Penetration Test Hammer's dynamic energy efficiency by using dongjaeha analyzer. this research, we installed strain gage and accelerometer for supply existing equipment, and develop MCP that can use variety soils. this thesis, we measured energy at head and tip of Rod for evaluating energy that transport at free falling. As a result, Energy differences are occurred at head and tip of Rod.

• 비파괴검사학회지
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• 제28권4호
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• pp.372-376
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• 2008

We report experimental results on the correlations between welding penetration depth and the frequencies of the radiation from the welding pool. Various welding samples such as SUS304, brass, SUS316, etc. have been investigated with 2 kW CW Nd:YAG laser welding machine. The radiation signals from the plume generated by the interactions between the welding sample and laser with respect to the defocusing length was measured with fiber system collecting the plume signal. Analysis of the frequencies by using fast Fourier transform (FFT) shows that the penetration depth is deep as plume signal frequencies are low, shallow penetration depth for high frequencies. Frequencies up to 250 Hz for obtained signals can be analyzed with the discrete FFT. This is the useful method fur closed loop control of the laser power with respect to the welding penetration depth and is used for real time inspection of the welding quality.

• 한국지반신소재학회논문집
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• 제22권4호
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• pp.83-92
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• 2023

In this study, we conducted verification of key influencing factors during cone penetration testing using the developed Mini Cone Penetration Tester (Mini-CPT), and compared the experimental results with empirical formulas to validate the equipment. The Mini-CPT was designed to measure cone penetration resistance through a Strain Gauge, and the resistance values were calibrated using a Load Cell. Moreover, the influencing factors were verified using a model ground constituted in a soil box. The primary influencing factors examined were the boundary effect of the soil box, the distance between cone penetration points, and the cone penetration speed. For the verification of these factors, the experiment was conducted with the model ground having a relative density of 63.76% in the soil box. It was observed that the sidewall effect was considerably significant, and the cone penetration resistance measured at subsequent penetration points was higher due to the influence between penetration points. However, within the speed range considered, the effect of penetration speed was almost negligible. The measured cone penetration resistance was compared with predicted values obtained from literature research, and the results were found to be similar. It is anticipated that using the developed Mini-CPT for constructing model grounds in the laboratory will lead to more accurate geotechnical property data.