• The Journal of the Acoustical Society of Korea
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• 제18권3E호
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• pp.21-25
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• 1999

This paper proposes methods that replace a missing triphone with a new one selected or created by existing triphones, and compares the results. The recognition system uses DMS (Dynamic Multisection) model for acoustic modeling. DMS is one of the statistical recognition techniques proper to a small - or mid - size vocabulary system, while HMM (Hidden Markov Model) is a probabilistic technique suitable for a middle or large system. Accordingly, it is reasonable to use an effective algorithm that is proper to DMS, rather than using a complicated method like a polyphone clustering technique employed in HMM-based systems. In this paper, four methods of filling missing triphones are presented. The result shows that a proposed replacing algorithm works almost as well as if all the necessary triphones existed. The experiments are performed on the 500＋ word DMS speech recognizer.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.109-112
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• 2006

Social and environmental pressures draw greater significance on the recycling of the waste. Particularly, waste concrete is particularly crucial among the construction wastes in terms of conservation of natural construction resources as well as disposal crisis. The technology to recycle the waste concrete has been improved. This study has various replacement levels of natural fine aggregate with recycled fine aggregate while coarse aggregate is completely replaced with the recycled coarse aggregate and herein fundamental properties investigated include compressive strength, shrinkage and dynamic modulus of elasticity. As a result, it is anticipated that the recycled aggregate concrete can be successfully applied to structural concrete members provided a proper recycling process, mix design and curing method are practiced.

• 산업경영시스템학회지
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• 제28권3호
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• pp.149-155
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• 2005

In this paper, we optimize simulation model of a manufacturing system using the real-coded genetic algorithm. Because the manufacturing system expressed by simulation model has stochastic process, the objective functions such as the throughput of a manufacturing system or the resource utilization are not optimized by simulation itself. So, in order to solve it, we apply optimization methods such as a genetic algorithm to simulation method. Especially, the genetic algorithm is known to more effective method than other methods to find global optimum, because the genetic algorithm uses entity pools to find the optimum. In this study, therefore, we apply the real-coded genetic algorithm to simulation optimization of a manufacturing system, which is known to more effective method than the binary-coded genetic algorithm when we optimize the constraint problems. We use the reproduction operator of the applied real-coded genetic algorithm as technique of the remainder stochastic sample with replacement and the crossover operator as the technique of simple crossover. Also, we use the mutation operator as the technique of the dynamic mutation that configures the searching area with generations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.544-544
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• 2014

Energy harvesting technology, which scavenges electric power from ambient, otherwise wasted, energy sources, has been explored to develop self-powered wireless sensors and possibly eliminate the battery replacement cost for wireless sensors. Among ambient energy sources, vibration energy can be converted into electric power through a piezoelectric energy harvester. For the last decade, although tremendous advances have been made in design methodology to maximize harvestable electric power under a given vibration condition, the research in reliability assessment to ensure durability has been stagnant due to the complicated nature of the multiple failure modes of a piezoelectric energy harvester, such as the interfacial delamination, fatigue failure, and dynamic fracture. Therefore, this study presents the first-ever system reliability analysis for multiple failure modes of a piezoelectric energy harvester using the Generalized Complementary Intersection Method (GCIM), while accounts for the energy conversion performance. The GCIM enables to decompose the probabilities of high-order joint failure events into probabilities of complementary intersection events. The electromechanically-coupled analytical model is implemented based on the Kirchhoff plate theory to analyze its output performances of a piezoelectric energy harvester. Since a durable as well as efficient design of a piezoelectric energy harvester is significantly important in sustainably utilizing self-powered electronics, we believe that technical development on system reliability analysis will have an immediate and major impact on piezoelectric energy harvesting technology.

• Geomechanics and Engineering
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• 제13권6호
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• pp.929-946
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• 2017

Composite foundation treated with compaction piles can eliminate collapsibility and improve the bearing capacity of foundation in loess area. However, the large number of piles in the composite foundation leads to difficulties in the analysis of such type of engineering works. This paper proposes two simplified methods to quantify the stability of composite foundation treated with a large number of compaction piles. The first method is based on the principle of making the area replacement ratios of the simplified model as the same time as the practical engineering situation. Then, discrete piles arranged in a triangular shape can be simplified in the model where the annular piles and compacted soil are arranged alternately. The second method implements equivalent continuous treatment in the pile-soil area and makes the whole treated region equivalent to a type of composite material. Both methods have been verified using treated foundation of an oil storage tank. The results have shown that the differences in the settlement values obtained from the water filled test in the field and those calculated by the two simplified methods are negligible. Using stability analysis, the difference ratios of the static and dynamic safety factors of the composite foundation treated with compaction piles calculated by these two simplified methods are found to be 3.56% and 5.32%, respectively. At the same time, both static and dynamic safety factors are larger than the general safety factor, which should be greater than or equal to 2.0 according to the provisions in civil engineering. This indicates that after being treated with compaction piles, the bearing capacity of the composite foundation is effectively improved and the foundation has enough safety reserve.

• 한국정보과학회논문지:시스템및이론
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• 제36권6호
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• pp.451-462
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• 2009

최근에 하드 디스크의 낮은 입출력 처리 성능을 개선하는 연구가 활발하게 진행 중이다. 하드웨어 연구는 좋은 성과를 보이고 있지만 시스템의 입출력 성능향상을 지원해야 할 시스템 소프트웨어 기술 발전이 미진하여 하드웨어 성능을 최대로 발휘하지 못하고 있는 상황이다. 본 논문에서는 n-블록을 플래시 메모리로 선반입하는 새로운 방법을 제안한다. 제안한 방법은 세 단계로 구성된다: (1) 블록 단위 읽기 요청의 패턴을 분석하여 n-블록단위로 플래시 메모리에 선반입한다; (2) 입출력 요청 시에 그 블록의 위치를 판단하여 입출력 서비스를 제공한다; (3) 블록 교체 정책에 따라 n-블록을 교체한다. 이 방법을 통해 하드디스크의 대기시간을 줄이고 전력 사용을 최적화 할 수 있다. 실험을 통해 제안한 동적 n-블록 방법이 기존의 AMP(Adaptive multistream prefetching) 방법과 비교하여 9.05%의 평균응답시간을 개선하고 평균전력소모를 11.11% 감소시킴을 확인하였다.

• Steel and Composite Structures
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• 제24권1호
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• pp.113-128
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• 2017

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.240-241
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• 2014

The environmental pollution problem the globally related to global warming arises. In the construction industry the cement mostly use material, generates the great quantity of CO₂ among the fired process and the global warming is more aggravated. In addition, the polysilicon that is the main raw material used in the solar power generation, produces 1 ton and the industrial by-product of 2 tons is generated. In this way, the arising sludge there is not method recycling and it is all discarded. Therefore, in this research, try to present as the fundamental research material for using the polysilicon sludge as the admixture of the cement in order to reduce the amount of the cement. The based on 'KS L ISO 679' was progressed mortar test. the liquidity, air flow rate, setting time, water absorption ratio, flexural and compression strength was measured. According to, appropriate replacement ratio of the polysilicon sludge tries to analyze.

• Steel and Composite Structures
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• 제25권4호
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• pp.427-442
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• 2017

This paper presents unprecedented damped oscillation behaviours of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an innovative slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both undamped and damped eigenfrequencies and eigenmodes have been extracted using the Lancsoz method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

• Advances in concrete construction
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• 제16권5호
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• pp.269-276
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• 2023

In order to study the effect of rubber particle size and admixture on the frost resistance of self-compacting concrete, three self-compacting concrete specimens with equal volume replacement of fine aggregate by rubber particles of different particle sizes were prepared, while conventional self-compacting concrete was made as a comparison specimen. The degradation law of rubber aggregate self-compacted concrete under freeze-thaw cycles was investigated by fast-freezing method test. The results show that the rubber aggregate has some influence on the mechanical properties and freeze-thaw durability of the self-compacting concrete. With the increase of rubber aggregate, the compressive strength of self-compacting concrete gradually decreases, and the smaller the rubber aggregate particle size is, the smaller the effect on the compressive strength of the matrix; rubber aggregate can improve the frost resistance of self-compacting concrete, and the smaller the rubber particle size is, the more obvious the effect on the improvement of the frost resistance of the matrix under the same dosage. Through the research of this paper, it is recommended to use 60~80 purpose rubber aggregate and the substitution rate of 10% is chosen as the best effect.