• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.731-738
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• 2002

Recently, as large constructions on the coast are performed frequently, surface layer stabilization method which Is one of the improvement methods for dredged soft clay has been applied. However, there have been few studies about the surface layer stabilization method. The purpose of this study is to clarify characteristics of ultra-soft marine clay and hardening agent. Also, optimal mixture ratio of hardening agent was verified through the laboratory tests such as statistical analysis and pilot tests. Laboratory tests were performed with proper hardening agent and test soil and standard mixing tables of hardening agent were determined according to ground conditions through statistical analysis. Also, applicability of surface layer stabilization method to field was verified by pilot tests. From the results of the tests, it was found that hardening agent materials such as cement, slag, fly-ash, inorganic salts, arwin, gypsum etc. affect on the appearing compressive strength. It was defined optimal mixture ratio which satisfies the required compressive strength from the statistical analysis. Also, It was compared the effect of ground improvement by cements and hardening agents through the pilot tests. This study will serve as data for design or construction criteria of stabilization of surface layer on ultra-soft marine clay.

• 한국분말재료학회지
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• 제28권3호
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• pp.233-238
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• 2021

Iron-based amorphous powder attracts increasing attention because of its excellent soft magnetic properties and low iron loss at high frequencies. The development of an insulating layer on the surface of the amorphous soft magnetic powder is important for minimizing the eddy current loss and enhancing the energy efficiency of high-frequency devices by further increasing the electrical resistivity of the cores. In this study, a hybrid insulating coating layer is investigated to compensate for the limitations of monolithic organic or inorganic coating layers. Fe₂O₃ nanoparticles are added to the flexible silicon-based epoxy layer to prevent magnetic dilution; in addition TiO₂ nanoparticles are added to enhance the mechanical durability of the coating layer. In the hybrid coating layer with optimal composition, the decrease in magnetic permeability and saturation magnetization is suppressed.

• 한국안전학회지
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• 제16권1호
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• pp.53-58
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• 2001

Constructions on the soft clay layer of low strength and high compression bring out many problems. Recent studies show that strength of the soft clay layer could be substantially improved by mixing quicklime. For the purpose, a series of uniaxial compression tests were performed, using quicklime, in order to analyze strength characteristics. The major test results are summarized following : When water content is 90%, the strength is observed to precipitously increase between 3～14 days, then, the extent slowly increase in relative terms. When water content is 130%, the strength is observed to precipitously increase up to 28 days. When the strength of water content 90% is compared to that of water content 130%, the initial strength of the former is higher than that of the latter. The analyses show that the improvement of soft clay layers can be realized by the mixture of both quicklime and sand, and by the mixture of quicklime only.

• Geomechanics and Engineering
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• 제35권5호
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• pp.511-523
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• 2023

Canal-side roads frequently collapse due to an unexpectedly greater soft-clay thickness with a rapid drawdown situation. This causes annually increased repair and reconstruction costs. This paper aims to explore the effect of soft-clay thickness on the failure in the canal-side road in the case study of Phra Nakhon Si Ayutthaya rural road no. 1043 (AY. 1043). Before the actual construction, a field vane shear test was performed to determine the undrained shear strength and identify the thickness of the soft clay at the AY. 1043 area. After establishing the usability of AY. 1043, the resistivity survey method was used to evaluate the thickness of the soft clay layer at the failure zone. The screw driving sounding test was used to evaluate the undrained shear strength for the road structure with a medium-stiff clay layer at the failure zone for applying to the numerical model. This model was simulated to confirm the effect of soft-clay thickness on the failure of the canal-side road. The monitoring and testing results showed the tendency of rapid drawdown failure when the canal-side road was located on > 9 m thick of soft clay with a sensitivity > 4.5. The result indicates that the combination of resistivity survey and field vane shear test can be successfully used to inspect the soft-clay thickness and sensitivity before construction. The preliminary design for preventing failure or improving the stability of the canal-side road should be considered before construction under the critical thickness and sensitivity values of the soft clay.

• 한국지반환경공학회 논문집
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• 제9권1호
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• pp.41-46
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• 2008

본 연구에서는 대심도 연약지반에서 PHC말뚝을 항타관입한 후 일정기간 이후 정재하시험을 통한 하중전이분석을 실시하였다. 하중전이분석에서 단위주면마찰력은 상부의 사질토에서 $7.4t/m^2$, 심도 14m에서 33m의 점성토구간에서는 $6.4t/m^2$, 말뚝선단부가 근입된 사질토에서는 $23.3t/m^2$이 발휘되었으며, 단위선단지지력은 $955t/m^2$으로 실측되었다. 전이된 단위주면마찰력과 국내외에서 알려져 있는 정역학적 지지력산정식과의 비교를 해본 결과 토층별로 가장 적합한 공식을 선정한다면, 사질토의 단위주면마찰력의 경우 한국지반공학회의 구조물기초설계기준 및 해설이, 점성토의 단위주면마찰력의 경우 철도청의 철도설계기준이 가장 실측치에 근접한 값을 나타내었다.

• 한국지반환경공학회 논문집
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• 제4권4호
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• pp.61-71
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• 2003

실트질 점토로 이루어진 연약지반의 호안 제방축조는 성토 제방하중에 의한 연약지반내 강제치환 공법으로 이루어지고 있으며, 축조 제방하부 강제치환 깊이는 호안 제방의 안정성에 큰 영향을 미치고 있다. 기존의 제방하부 강제치환 깊이 산정방법은 하부 연약점토지반의 비배수 전단강도 증분율을 고려한 제방하부 연약지반의 지지력과 성토제방 하중에 의해 산정하고 있다. 그러나 지반 층후 특성에 따라 중간층 형태의 점토질 실트층 또는 모래층이 있는 경우가 있으며, 이러한 점토질 실트층 또는 모래층은 제방하부 연약지반의 지지력에 영향을 미치게 되어 강제치환 깊이에 영향을 미치게 된다. 본 논문에서는 중간 모래층이 있는 연약지반내 제방 축조시 강제치환 깊이를 Perloff et al.(1967) 영향계수를 고려한 성토제방 하중과 층두께 가중평균 지지력(Bowles, 1988)에 의해 산정하였으며, 수치해석(FLAC)적 방법에 의한 산정결과와 비교 분석하였다. 해석결과 제방하부 접지폭이 $0.2B_o$(중간 모래층), $0.5B_o$(단일층)인 경우 산정된 강제치환 깊이는 수치해석과 매우 근접하는 것을 알 수 있었으며, 제방 하부 접지폭의 영향보다 비배수 전단강도 및 중간 모래층 두께, 중간 모래층 위치의 영향이 큰 것을 알 수 있었다. 또한 중간 모래층 두께가 작을수록 강제치환 깊이는 증가하며, 중간 모래층 위치가 증가 할수록 강제치환 깊이는 증가하고, 비배수 전단강도가 감소할수록 강제치환 깊이가 증가하는 것을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.888-892
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• 2004

It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/［Ni-Fe/si］ layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

• 방송공학회논문지
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• 제24권6호
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• pp.1072-1075
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• 2019

본 레터는 ATSC3.0 Layered-Division-Multiplexing Multiple-Inputs-Multiple-Outputs 방송 시스템에서 Core-Layer (CL) 전송 신호에 대한 새로운 연판정 복조 기법을 제안하고자 한다. 제안된 기법은 기존의 Guassian-Approximation (GA) 기법과 달리 동시에 전송되는 Enhanced-Layer 신호를 QPSK 신호로 모델링하여 CL 전송 신호를 복호하게 되며, 실험 결과 CL injection-level이 작을수록 기존의 GA 기법에 비하여 월등한 성능 향상을 보인다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.96-99
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• 2001

The formation of soft magnets on paper(SMOP) is proposed for the first time and we have demonstrated it successfully. Iorn was used to form the soft magnet thin film on paper. And Cr layer was used as a buffer layer because the roughness of substrate(paper) is not negligible. The maximum magnetization of Cr/Fe/Cr/Paper(Fe:5000${\AA}$) is about 1000 [emu/cc] and the coercive field is about 80 [Oe.]. It is necessary to reduce the coercivity and to enlarge the magnetization value of SMOP to perform a good soft magnetic characteristics on paper. On, the permalloy material is the proper candidate for its high permeability, low coercivity and high magnetization values.

• 한국정보통신학회논문지
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• 제25권2호
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• pp.330-333
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• 2021

In a CNN for image classification, a SoftMax layer is usually placed at the end. The exponentinal and logarithmic operations in the SoftMax layer are not adequate to be implemented in an accelerator circuit. The operations are usually implemented with look-up tables, and the exponential operation can be implemented in an iterative method. This paper proposes a successive approximation method to calculate a logarithm to remove a very large look-up table. By substituing the large table with two very small tables, the circuit can be reduced much. The experimental results show that the 85% area reduction can be reached with a small error degradation.