• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.120-121
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• 2017

Generally, slump of plain concrete slab is about 120~150mm and slump loss is easy to occur. So, water is added to concrete because this method is convenient for Placing. In order to solve this problem, performance evaluation of concrete using improvement type PC admixture was carried out. Target slump is 210mm and compressive strength is 18MPa. As a result, slump reference value was satisfied 60 minutes after placing and 7-day compressive strength was 21~25MPa.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.140-148
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• 2012

Recently there are many attempts to introduce PC construction method in buildings. But the study on PC structural wall has been made progress so slowly because it is very difficult to develop new items. In this study, we have developed new vertical joint on PC wall in order to upgrade constructivity and structural performance of the existing connections, then we have evaluated the seismic resistance performance. As a result of the cyclic loading tests for two specimens, proposed vertical joint on PC wall has shown that it behave the excellent structural performance in comparison to PC wall having no joint. Therefore, we think that proposed vertical joint is the system to apply buliding structure.

• The Journal of the Acoustical Society of Korea
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• v.18 no.8
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• pp.3-8
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• 1999

Previous variable vocabulary speech recognition systems with context-independent acoustic modeling, could not represent the effect of neighboring phonemes. To solve this problem, we use allophone-based context-dependent acoustic model. This paper describes the method to improve acoustic model of the system effectively. Acoustic model is improved by using allophone clustering technique that uses entropy as a similarity measure and the optimal allophone model is generated by changing the number of allophones. We evaluate performance of the improved system by using Phonetically Optimized Words(POW) DB and PC commands(PC) DB. As a result, the allophone model composed of six hundreds allophones improved the recognition rate by 13% from the original context independent model m POW test DB.

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.364-369
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• 2006

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.441-450
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• 2010

This is a preliminary study on the development of precast beam-column joints for dry construction methodology. Precast beam column joints with thru-connectors (BCJ_TC) using high strength bars or PS strands were developed and their seismic performance including strength degradation, stiffness degradation and energy dissipation capacity was experimentally evaluated. Test results showed that compressive failures at the end blocks of PC beam members occurred dominantly while PC columns including panel zones were free from any damage. However, the connections confined with CFRP at the end block showed much improved seismic performance than that of the unconfined connections. Connections with neoprene pad fillers between beam and column interfaces were better than the other connections in all the seismic performances except initial stiffness. To improve the seismic performances of BCJ_TC, compressive strength of the concrete at the end block need to be increased to compensate for the additional compressive stresses due to unbonded connectors and deformation of connectors should be controlled respectively.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.110-112
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• 2003

본 논문에서는 확률적인 전역 최적화 알고리즘인 유전 알고리즘과 경험적인 최적화 알고리즘인 타부 탐색법을 병렬화함으로써 최적해 탐색성능 및 탐색속도를 개선하는 방안을 개발하였다. 배전계통의 주변압기에서 고장이 발생한 경우에는 여러 정전구역에 대한 복구문제가 되어 매우 복잡하고 많은 연산량을 수반한다. 따라서 제안한 고장복구 알고리즘은 PC 클러스트링을 이용하여 각 프로세서별로 유전 알고리즘 또는 타부 탐색법을 사용하여 최적해를 탐색한 후 일정 기간 이후에 해를 교환함으로써 배전계통에서의 주변압기 고장발생시 최적해 탐색에 소요되는 시간을 단축하였으며 고장복구 지원시스템의 성능개선을 도모하였다. 제안한 알고리즘의 유용성을 입증하기 위하여 한전의 실 배전계통 주변압기 고장복구 문제에 적용함으로써 제안한 알고리즘이 해의 탐색속도 및 해의 성능면에서 우수함을 입증하였다.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.445-451
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• 2017

Because of the supply-demand problem of aggregate, recently, the construction sites using 100% crushed sand are increasing and the use of low quality aggregate such as farmland sand is increasing too. When the low quality aggregate is used, the various quality defect of concrete such as the strength reduction, the increase of shrinkage and bleeding can be occurred. Therefore, in this study, the performance improvement PC admixture was developed to minimize the quality defect of plain concrete of basement parking area, when the low quality aggregate was used at the plain concrete of basement parking area. The slump loss to elapsed time test, the compressive strength test, the bleeding test and the drying shrinkage test were carried out.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.984-989
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• 2010

In this paper, parallel programming technique by using Java Thread is introduced so as to develop parallel design tool to analyze the small micro flow sensor. To estimate computing time for Thread-level parallelism, the performances of two experimental models for potential problem subject to Thermal transfer equation are examined. As a result, if the number of network PC is increase, computing time for parallelism on network environment is enhanced to be almost n times. The micro sensor design tool based on distributed computing can be utilized to analyze a large scale problem.

• KIISE Transactions on Computing Practices
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• v.22 no.7
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• pp.303-309
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• 2016

Recently, an increasing number of embedded processors such as ARM Mali begin to support GPGPU programming frameworks, such as OpenCL. Thus, GPGPU technologies that have been used in PC and server environments are beginning to be applied to the embedded systems. However, many embedded systems have different architectural characteristics compare to traditional PCs and low-power consumption and real-time performance are also important performance metrics in these systems. In this paper, we implement a parallel AES cryptographic algorithm for a modern embedded GPU using OpenCL, a standard parallel computing framework, and compare performance against various baselines. Experimental results show that the parallel GPU AES implementation can reduce the response time by about 1/150 and the energy consumption by approximately 1/290 compare to OpenMP implementation when 1000KB input data is applied. Furthermore, an additional 100 % performance improvement of the parallel AES algorithm was achieved by exploiting the characteristics of embedded GPUs such as removing copying data between GPU and host memory. Our results also demonstrate that higher performance improvement can be achieved with larger size of input data.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.579-584
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• 1997

HP Workstation 및 IBM PC에서 사용 가능한 부수로 해석 코드 MATRA $\alpha$-버전을 개발하였다. 이 코드는 정확도 향상 및 사용자 편리를 위해 COBRA-IV-I코드에 비해 여러가지 기능들이 추가되었으며, 코드의 적용 범위를 신형원자로의 비정방형 집합체 노심에 확장할 수 있도록 압력손실 모형 등이 개선되었다. 또한 이상 유동장에서의 예측 정확도 향상을 위하여 부수로 잔의 횡방향 전달 모형을 개선하였다. 코드의 예측 성능을 평가하기 위해 세 중류의 집합체 유동분포 및 엔탈피 분포 실험 자료와 비교하였으며, 그 결과 기존의 COBRA-IV-I코드보다 향상된 결과를 보였다.