• Journal of Korea Water Resources Association
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• v.48 no.7
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• pp.595-604
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• 2015

Interrill erosion by the rainfall is divided into a detachment of soil particles by raindrop splash when raindrops having kinetic energy strike on the surface soil and a sediment transport by sheet flow of surface runoff. Rainfall kinetic energy is widely used as an indicator expressing the potential ability to separate the soil particles from soil mass. In this study, the soil erosion experiments of rainfall simulation were operated to evaluate the effects of rainfall kinetic energy on interrill erosion as using the strip cover to control raindrop impact. The kinetic energy from rainfall simulator was 0.58 times to that of natural rainfall. Surface runoff and subsurface runoff increased and decreased respectively with increase of rainfall intensity. Surface runoff discharge from plots of non-cover was 1.82 times more than that from plots with cover. The rainfall kinetic energy influenced on the starting time of surface and subsurface runoff. Soil erosion quantity greatly varied according to existence of the surface cover that can intercept rainfall energy. Sediment yields by the interaction between raindrop splash and sheet flow increased 3.6~5.9 times and the increase rates of those decreased with rainfall intensity. As a results from analysis of relationship between stream power and sediment yields, rainfall kinetic energy increased the transport capacity according to increase of surface runoff as well as the detachment of soil particles by raindrop splash.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.102-104
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• 2005

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.645-651
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• 2006

This paper discusses computer system performance evaluation and analysis by employing a simulator which able to execute a symmetric multiprocessor in machine simulation environment. We also perform a multiprocessor system analysis using SPLASH-2, which is a suite of multi-program benchmarks for multiprocessors, to perform the behavior study of the symmetric multiprocessor OS kernel, IRIX5.3. To validate the scalability of symmetric multiprocessor system, we demonstrate structure and evaluation methods for symmetric multiprocessor as well as a functionality-based software simulator, SimOS. In this paper, we examine cache miss count and stall time on the symmetric multiprocessor between the local instruction and local data, using the multi-program benchmarks such as RADIX sorting algorithm and Cholesky factorization.

• Journal of ILASS-Korea
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• v.17 no.3
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• pp.128-133
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• 2012

The present study aims to examine the influence of flame spray distance on the thermal behavior of micro-metal particles and the morphological characteristics of $Ni_{20}Cr$ layers coated on the preheated SCM415 substrates by using the conventional flame spray system. Commercially available nickel-based $Ni_{20}Cr$ particles with a mean diameter of $45{\mu}m$ were used. In addition, CFD simulations using a commercial code (FLUENT ver. 6.3.26) were conducted to estimate temperature and velocity distributions of the continuous and discrete phases before impact on the substrate. From FE-SEM images of coated layers on the substrates, it was observed that as the spray distance decreased, the metal particle morphology showed splash-like patterns and such a short stretch shape, resulting from higher particle momentums and the impact of partially melted particles. Moreover, it was found that the spray distance should be considered as one of important parameters in controlling the porosity and the adhesion strength.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1101-1117
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• 2006

In the present article, recent progress of spray-wall interaction research has been reviewed. Studies on the spray-wall interaction phenomena can be categorized mainly into three groups: experiments on single drop impact and spray (multiple-drop) impingement, and development of comprehensive models. The criteria of wall-impingement regimes (i.e., stick, rebound, spread, splash, boiling induced breakup, breakup, and rebound with breakup) and the post-impingement characteristics (mostly for splash and rebound) are the main subjects of the single-drop impingement studies. Experimental studies on spray-wall impingement phenomena cover examination of the outline shape and internal structure of a spray after the wall impact. Various prediction models for the spray-wall impingement phenomena have been developed based on the experiments on the single drop impact and the spray impingement. In the present article, details on the wall-impingement criteria and post-impingement characteristics of single drops, external and internal structures of the spray after the wall impact, and their prediction models are reviewed.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.461-468
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• 2001

Though shared virtual memory (SVM) system promise low cost solutions for high performance computing they suffer from long memory latencies. These latencies are usually caused by repetitive invalidations on shared data. Since shared data are accessed through synchronization and the patterns by which threads synchronizes are repetitive, a prefetching scheme bases on such repetitiveness would reduce memory latencies. Based on this observation, we propose a prefetching technique which predicts future access behavior by analyzing access history per synchronization variable. Our technique was evaluated on an 8-node SVM system using the SPLASH-2 benchmark. The results show the our technique could achieve 34%~45% reduction in memory access latencies.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.299-306
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• 2017

In this research, it was examined chloride ion penetration resistance of slag-replaced concrete and cementless slag concrete considering marine environmental exposure conditions of splash zone, tidal zone and immersion zone. In the design strength of grade 24 MPa, the specimens were tested to determine their compressive strength, scanning electron microscopy images and chloride migration coefficient. Further, chloride ion penetration depth and carbonation depth of specimens exposed to marine environment were measured. Experimental results confirm that chloride migration coefficient of specimens tended to decrease with increasing the replacement ratio of ground granulated blast-furnace slag in accelerated laboratory test. In addition, the specimens exposed to the tidal zone were found to be the greatest chloride ion penetration depth compared to splash zone and immersion zone. On the other hand, the chloride ion penetration depth of the specimens exposed to splash zone tended to increase with increasing the replacement ratio of ground granulated blast-furnace slag in contrast with the results for the tidal zone and immersion zone.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.525-530
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• 2005

The erosion rate of water wall tube has been measured and discussed in a commercial circulating fluidized bed combustor (200 ton steam/hr, $4.97{\times}9.90{\times}28.98m\;height$). Tube thickness was measured with ultrasonic method. Severe tube erosion rate was observed in the splash region on all waterwalls including wingwalls. The tube erosion rate increased after an initial decrease as height from the distributor increased. The difference of erosion rate among wing walls was found due to unbalanced distribution of gas and solid flow rates. The erosion rate of the wing wall increased as location of the wing wall became closer to the center of combustor crosssection.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.73-81
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• 2004

On this study, durability decreasing element caused by salt damage was analyzed elementally and studied with the data of the inside and outside in the country. The design strength and water-cement ratio according to diffusion coefficients of chloride were applied to Fick's diffusion equation. The required over depended on environmental conditions is estimated with endurance period, and the influences on cover according to the transformation of the each parameter were investigated. In consequence, if water-cement ratio decreases and design strength increases, it shows that slowing infiltration velocity of chloride ion can decrease required cover. Especially, it is more effective to use Portland blast-furnace slag cement into high strength concrete in the splash zone environmental conditions in blocking the diffusion of chloride ion. As the result, in the case of the offshore concrete structure needed high durability, it is needed to increase cover($3cm{\sim}8cm$) than minimum standard cover(8cm) according to environmental conditions.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.1
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• pp.37-47
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• 1993

최근에 치명적인 바이러스, 특히 에이즈를 이르키는 Human Immunodificiency Virus (HIV), 또는 간에 심각한 병을 이르키는 Hepatitis B Virus (HBV)와 같은 무서운 바이러스가 환자의 피나 분비물을 통하여 의사에게 전염되는 사례가 늘어감에 따라 이제는 환자의 피나 분비물의 침투를 막기 위해 방수성과 방균성을 가진 수술복 착용이 절대적으로 필요하게 되었다. 따라서 본 연구의 목적은 1. 수술가운을 만드는 5가지 대표적인 직물의 방수성과 방균성을 측정하고 2. 세탁시 표백제의 사용유무가 그 직물의 방수성과 방균성에 미치는 영향을 알아보고 3. 반복세탁이 그 직물의 방수성과 방균성에 미치는 영향을 알아 보는데 있다. 이 실험을 위해 3가지 재사용 수술가운과 (Gore-tex$^R$, membrane reinforced; Compel$^{TM}$, fabric reinforced; Acep$^{TM}$, non-reinforced) 두 가지 일회용 가운 (Evolution$^R$ gown, fabric reinforced; Evolution$^R$ Specialty, film reinforced)이 사용되었다. 표백제를 사용한 세탁이 직물의 방수성과 방균성에 미치는 영향을 알아보기 위해 재사용 가운을 세탁, 건조, 살균을 하였다. 세탁과 살균의 빈도수는 1, 20, 40, 50, 60, 70, 80번 이였다. 방수성 측정방법으로 1. Impact Penetration test (AATCC 42-1985), 2. Elbow Lean test, 3. Synthetic Blood Resistance test (ASTM F 23. 40. 01)가 사용되었고 방균성 측정방법으로 Viral Resistance test (ASTM F 23. 40. 02)가 사용되었다. 실험 결과는 다음과 같다. 1. Gore-Tex$^R$ 가운과 Evolution$^R$ Specialty 가운은 방수성과 방균성의 성질을 가졌다. 그러나 표백제를 사용하여 70번 세탁한 Gore-Tex$^R$ 가운은 membrane의 구조가 파괴되어서 방균성을 상실했다. 2. Evolution$^R$ 가운, Acep$^{TM}$ 가운과 Compel$^{TM}$ 가운은 오직 Impact Penetration test만 통과했다. 즉 이 직물들은 큰 압력의 가함이 없는 splash resistance만 가지고있다. 그러나 Acep$^{TM}$ 가운과 Compel$^{TM}$ 가운은 20번과 60번 세탁 후 각각 그들의 splash resistance 마져도 상실했다.