• Journal of the Korean Geotechnical Society
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• v.18 no.6
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• pp.17-24
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• 2002

The objective of the present research is to evaluate the wave propagation velocity and attenuation characteristics of kaolin clay specimens using ultrasonic testing. Test specimens with known initial micro-fabric were prepared using a two-stage slurry consolidation technique. For a known state of stress conditions, initial void ratio, and micro-fabric, a series of experiments were conducted to evaluate the longitudinal wave propagation velocity and associated damping behavior. The effects of major variables involved in ultrasonic testing of cohesive soil were considered in this study. Ultrasonic velocity was not correlated to the microfabric structure under the given consolidated pressure whereas ultrasonic attenuation was affected by the microstructural properties of the specimen.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.233-245
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• 2018

Interest to basal reinforced piled embankments is increasing recently due to their rapid construction and reliability. A comprehensive parametric study is conducted to determine effects of pile properties, reinforcement stiffness, embankment properties and soft soil properties into settlements, pressures and excess pore water pressure development and dissipations. Results which are obtained by using one-layer reinforcement during construction are compared with the results obtained by using two-layer reinforcement during construction. Finite element method is used during the parametric study. Second layer of reinforcement is placed in five different positions in order to reveal effects of reinforcement position into behaviour. Traffic load is also taken into consideration during the study. Differences between the results without presence of traffic loading and with presence of traffic loading is stated in this the study.

• Journal of Information Science Theory and Practice
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• v.6 no.3
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• pp.6-15
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• 2018

With the increasing demand for intelligent services, knowledge graph technologies have attracted much attention. Various application-specific knowledge bases have been developed in industry and academia. In particular, open knowledge bases play an important role for constructing a new knowledge base by serving as a reference data source. However, identifying the same entities among heterogeneous knowledge sources is not trivial. This study focuses on extracting and determining exact and precise entities, which is essential for merging and fusing various knowledge sources. To achieve this, several algorithms for extracting the same entities are proposed and then their performance is evaluated using real-world knowledge sources.

• Tunnel and Underground Space
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• v.4 no.1
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• pp.24-30
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• 1994

Although a dry-system tunnel is not good for reasons fo economy and construction, it has been applied to some tunnels under construction owing to the advantages of good long-term maintenance of tunnel, prevention of consolidation settlement due to the drawdown of groundwater, preservation of the ecosystem, cutailment of operation cost, and so on. The stability of groundwater and the change of the applied water pressure after water proofing were analysed by the finite element method. Using this result, an example of designing the secondary lining for the dry-system tunnel which is to be constructed in low-permeability hard rock was presented.

• Journal of Powder Materials
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• v.7 no.1
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• pp.27-34
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• 2000

The fabrication process and mechanical properties of SiC particle prefrrms with high volume fraction ranged 50∼71% were investigated to make metal matrix composites for possible applications as heat sinks in electronic packares. The SiC particle preforms with 50∼71vol% of reinforcement were fabricated by a new modified process named ball milling and pressing method. The SiC particle performs were fabricated by ball milling of SiC particles with single sized of 48${\mu}$m in diameter or two different size of 8${\mu}$m and 48${\mu}$min diameter, with collodal SiO2 as inorgnic binder in distilled water, and the mixed slurries were cold pressed for consolidation into final prefom. The compressive strengths og calcined SiC particle prefoms increased from 20MPa to 155MPa with increasing the content of inorganis binder, temperature and time for calcination. The increase of compressive strength of SiC particle bridge the interfaces of two neighboring SiC particles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.231-232
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• 2016

Configuration Management (CM) is a process of identifying and documenting the characteristics of a Structures, Systems and Components (SSCs), and of ensuring that changes to these characteristics are properly assessed, approved, issued, implemented and verified. There are requirement management, change control, facility configuration information management for CM activities. In order to improve safety of Nuclear Power Plant(NPP), it is necessary to manage change item systematically. Existing CM concept is focused on the NPP in operation. On the other hand, NPP under construction is difficult to efficiently manage the change because of different change process from varoius stake-holders. This research considers method of consolidation change process for NPP to ensure that approved changes are accurately reflected in the design requirements, facility configuration information, and the physical configuration.

• 기술발표회
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• s.2006
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• pp.248-260
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• 2006

광양항 3단계 1차 컨테이너터미널 부지 연약지반개량의 경우 광양지역의 특성상 재하용 토사확보 곤란, 시공기간 단축 및 환경훼손 최소화를 위해 진공압밀공법이 적용되었다. 본 사례연구에서는 진공압밀공법의 시공에 따른 문제점 및 개선사항을 제시하였고, 현장계측 및 진공 압밀완료 후에 실시된 지반조사 결과 등을 분석하여 준설매립지반에서의 진공압밀공법의 적용성을 평가하였다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1303-1304
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• 2006

The type, volume fraction, size, shape and arrangement of embedded particles influence the mechanical properties of the particle reinforced metal matrix composites. This presents the investigation of the SiC particle and porosity distributions in various aluminum matrix composites produced by cold- and hot-pressing. The microstructures were characterized by optical microscopy and stereological parameters. SiC and porosity volume fractions, and the anisotropy distribution function were measured to establish the influence of the consolidation method.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.599-605
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabilized sludge, as a backfill and cutoff-water materials for embanckment structures. for stabilizing of sludge, hydrated lime and quick lime was used as additive , and a series of tests was performed on the sludge and the stabilized sludge to examine their physical properties, compaction, compressive strength, hydraulic conducivity and consolication characteristics. From the test results, the physical and mechanical properteis of the stabilized sludge weremore improved as compared with the sludge. Especially from the viewpoint of physical porperty , consolidation or settlement and cutoff-water , quick lime is more effective than the hydraged lime as tabilizatio addtivie. But , viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as stabilization additive. As a result of this study, it was founded that the stabilized sludge can be developed the backfill and cutoff-water materials , improved the stabilizing method of sludge.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.396-401
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• 2013

The size of various alumina ceramics used in the semiconductor and display industries must be increased to increase the size of wafers and panels. In this research, large alumina ceramics were fabricated by pressure-vacuum hybrid slip casting (PVHSC) employing a commercial powder, followed by sintering in a furnace. In the framework of the PVHSC method, the consolidation occurs not only by compression of the slip in the casting room but also by suction of the dispersion medium from the casting room. When sintered at $1650^{\circ}C$ for 4 h, the fabricated large-size alumina ($1,550{\times}300{\times}30mm^3$) exhibited a dense microstructure corresponding to more than 99.2% of the theoretical density and a high purity of 99.79%. The flexural and compressive strengths of the alumina plate were greater than 340 MPa and 2,600 MPa, respectively.