• Horticultural Science & Technology
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• v.32 no.2
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• pp.241-251
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• 2014

This study was carried out to develop a simple, rapid and reliable assessment model to predict cold tolerance in Pittosporum tobira, a broad-leaved evergreen commonly used in the southern region of South Korea, which can minimize the possible experimental errors appeared in a electrolyte leakage test for cold tolerance assessment. The modeling procedure comprised of regrowth test and a electrolyte leakage test on the plants exposed to low temperature treatments. The lethal temperatures estimated from the methodological combinations of a electrolyte leakage test including tissue sampling, temperature treatment for potential electrical conductivity, and statistical analysis were compared to the results of the regrowth test. The highest temperature showing the survival rate lower than 50% obtained from the regrowth test was $-10^{\circ}C$ and the lethal was $-10^{\circ}C{\sim}-5^{\circ}C$. Based on the results of the regrowth test, several methodological combinations of electrolyte leakage tests were evaluated and the electrolyte leakage lethal temperatures estimated using leaf sample tissue and freeze-killing method were closest to the regrowth lethal temperature. Evaluating statistical analysis models, linear interpolation had a higher tendency to overestimate the cold tolerance than non-linear regression. Consequently, the optimal model for cold tolerance assessment of P. tobira is composed of evaluating electrolyte leakage from leaf sample tissue applying freeze-killing method for potential electrical conductivity and predicting lethal temperature through non-linear regression analysis.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.333-341
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• 2014

To supply substitution water, $2m^3$ of capacity of rainwater harvesting system is designed calculating rainfall, catchment area and LPCD and has a effects to 34.4% of substitution water supply and 237 days of service day. Rainwater of drinking water quality was judged to be suitable except for bacteria problem, however, groundwater is exceeded in nitrate nitrogen, the evaporation residue and also bacteria, which means that the rainwater is suitable for use as water supply. In addition, to consider cost-benefit ratio, economic analysis conducted. The result is that B/C ratio of RWHS (10 years) is 1.70. It means total benefit is bigger than cost. Except to social factor in this study, there are a variety of benefit such as flood or drought prevention, educational effects inspiring water conservation awareness.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.392-395
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• 2009

응답면 기법을 활용하여 댐구조물과 같은 사회간접자본 시설물의 파괴확률을 구할 수 있다. 본 위험성 평가과정에서 응답면기법으로 구성한 한계상태 방정식을 유전자알고리즘의 적합도 방정식으로 사용하면, 핵심타입이나 지반종류, 지반다짐정도 등의 입력설계변수의 최적화 과정 속도를 더욱 신속화 시킬 수 있다. 제안된 응답면 기법과 유전자알고리즘의 복합해석기법은 신뢰성기반 최적화프로그램으로 기존의 유전자알고리즘의 수렴속도를 더욱 빠르게 하여주고, 특히 입력변수의 상하한계가 불확실한 경우에도 만족스러운 수렴성을 보장하여준다. 한계상태 방정식의 목표신뢰도 지수를 변화시켜면 해당하는 입력변수의 최적값을 출력하여주므로, 입력변수의 제약조건에 가격함수와 같은 가중치를 벌칙함수로 부여하면 가격최적화 프로그램으로 작용하게 되며, 시설물 운영자에게는 목표신뢰도에 대한 유지관리 기법과 정도를 의사결정 할 수 있도록 하여주는 기능을 가지게 된다. 조사된 많은 댐구조물의 파괴모드가 시간에 독립적으로 시공중 또는 시공완료 후 5년이내에 다수 발생하는바, 파괴모드를 조사하고 중요한 파괴모드인 파이핑 현상에 대해서 파괴확률을 계산하고 최적유지관리를 위한 개선된 유전자알고리즘 최적화 연산을 수행하였다. 기존 댐구조물과 같이 설계변수와 하중의 변동성을 알기가 어려운 경우에 유지관리비용 최소화를 위해서 본 제안 프로그램의 확장된 버젼은 중요한 기준을 제시하여줄 것으로 기대한다.

• Clean Technology
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• v.17 no.2
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• pp.117-123
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• 2011

In this study, evaluation tests for cleaning performance of various cleaning agents and selection of optimal ultrasonic cleaning parameters were executed to develop an efficient cleaning process in remanufacturing of laser copy machine. Cleaning performance tests were executed with 8 cleaning agents (A~H) to remove the contaminants of oil-ink, toner particles, and shoe polish. Physical properties and foamability tests were also applied. For 3 types of contaminants, cleaning agent G showed superior cleaning performance compared to agent A which has being used at a remanufacturing of laser copy machine in Korea. With cleaning agents selected in pre-tests, ultrasonic cleaning tests were executed to remove real contaminants on the parts of used digital laser copy machine parts. Cleaning agent G at 28 kHz ultrasonic frequency showed faster cleaning performance compared to agent A and other frequencies. The productivity and economic efficiency in remanufacturing of laser copy machine are expected to increase by adapting agent G and 28 kHz frequency at ultrasonic cleaning process.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.514-520
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• 2021

In this study, EMP shielding performance was evaluated using electric furnace oxidized slag to give EMP shielding performance to concrete among the most used materials in construction sites. As a result of the evaluation, the component of the electric furnace oxidation slag was found to have an Fe₂O₃ content of 34%, and it was also found to contain an MgO component of about 4.8%. In addition, as a result of conducting an aggregate stability evaluation due to concerns about expansion due to MgO components, it is considered to be suitable for the KS standard. EMP shielding performance evaluation result showed that there was no correlation in EMP shielding performance according to compressive strength, and that general aggregates did not have EMP shielding. However, it was found that the aggregate using the furnace oxidized slag had excellent EMP shielding performance, and the shielding performance improved as the thickness increased. As a result of the durability evaluation, it was found that the EMP shielding concrete has the durability of abortion compared to the general concrete. Through this, it is thought that it will be good to improve the shielding rate if concrete is manufactured using electric furnace oxide slag when constructing EMP shielding structures in the future.

• Resources Recycling
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• v.25 no.2
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• pp.60-68
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• 2016

In this study, earlier analyzed tetrapod, one of an original group of offshore constructions studied for manufacturability of the concrete using the properties of steel making slag aggregate. steel making slag aggregate assessment, RCS and Blast Furnace Slag : the 20 mm air-cooled slag and combinations by 50 %, aggregate properties on the most appropriate for the properties of recycled aggregate concrete optimal mix, and assessing it. Properties of concrete used to be derived are judged as to bury the studies show that the hollowing-out of the RCS, plastic sole use is in the workability of the aggregate, plastic in the 20 mm slag also assessed to be a slight disadvantage, but RCS by mixing air-cooled coarse and 50 percent to 20 percent 50 mm. Thus, steel making slag marine structures using recycled aggregate, in rapid chilled slag or air-cooled slag. The sole use of the aggregate them than to combine the aggregate of concrete. After they satisfy the quality standard quality shall be used will aggregate steel making slag who meet the criteria concrete manufacturing in general or par with the aggregate of concrete. Performance was assessed as to develop a more than that.

• Journal of KIISE:Software and Applications
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• v.34 no.10
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• pp.900-909
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• 2007

This paper describes an experiment on the evaluation of human sensibility by monitoring responses to changes In the frequency and amplitude of a tactile display system. Preliminary tasks were performed to obtain effective adjectives concerning texture perception. The number of collected adjectives was originally 33. This number of adjectives was reduced to 14 by a suitability survey that asked whether an adjective is suitable for expressing a texture feeling. Finally after performing a semantic similarity evaluation, the number of adjectives was further reduced to ten and these ten were used in the main experiment. In the main experiment, selected sandpaper types and 15 selected combinations of frequencies and amplitudes of a tactile display were utilized to quantitatively evaluate the ten adjectives using a bipolar seven-point scale. The data show that a relationship exists between the independent variables(frequency, amplitude, and grit site) and the dependent variable(perceived texture). That is, the change of frequency and amplitude is directly related to perceived roughness or essential elements of human tactile sensitivity found in the preliminary experiment.

• Ecology and Resilient Infrastructure
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• v.10 no.1
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• pp.11-19
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• 2023

Alien species are known to threaten regional biodiversity globally, which has increased global interest regarding introduction of alien species. The Ministry of Environment of Korea designated species that have not yet been introduced into the country with potential threat as alert alien species to prevent damage to the ecosystem. In this study, potential habitats of Esox lucius and Maccullochella peelii, which are predatory and designated as alert alien fish, were predicted on a national basis. Habitat suitability was evaluated using EHSM (Ecological Habitat Suitability Model), and water temperature data were input to calculate Physiological Habitat Suitability (PHS). The prediction results have shown that PHS of the two fishes were mainly controlled by heat or cold stress, which resulted in biased habitat distribution. E. lucius was predicted to prefer the basins at high latitudes (Han and Geum River), while M. peelii preferred metropolitan areas. Through these differences, it was expected that the invasion pattern of each alien fish can be different due to thermal preference. Further studies are required to enhance the model's predictive power, and future predictions under climate change scenarios are required to aid establishing sustainable management plans.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.369-372
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• 2011

양 방향성 필터는 이미지표면 평탄화와 잡음제거에 좋은 성능을 보이지만 특유의 연산 복잡도로 인하여 연산 시간이 오래 걸린다는 단점이 존재한다. 따라서 본 논문에서는 고도의 병렬수행을 바탕으로 하는 그래픽연산장치(GPU)에 적합하도록 수정된 효율적인 양 방향성 필터를 NVIDIA 의 CUDA 를 사용하여 GTX 285 GPU 에서 구현하였다. 영상의 전 영역을 참조하는 대신 인접하고 연속된 영역으로의 근사화, 적은 메모리 사용량, 빠른 접근속도를 가지며 충돌이 최소화된 공유메모리 버퍼, Warp 를 고려한 병합된 메모리 접근방법을 바탕으로 병렬화 하였다. 그 결과, 같은 방식의 순차실행 알고리즘 대비 최소 약 34 배에서 최대 약 76 배의 속도 개선과 30dB 내외의 PSNR 을 갖는 양 방향성 필터를 구현할 수 있었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.24-31
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• 2024

Mortar has been applied in most previous studies on 3D concrete printing. In such cases, however, the economic efficient cannot help decreasing due to higher binder contents and larger amount of fine aggregates. In order to enhance the applicability of 3D printing technology to construction industry, therefore, 3D concrete printing technology utilizing coarse aggregates needs to be developed further. This study aims at proposing the mix design process of concrete containing coarse aggregates for 3D printing. Based on extensive literature review and experimental studies, the mix proportion suitable for 3D printing has been derived, and the extrudability of concrete with coarse aggregates has been verified through 3D printing tests. The primary variable of the extrudability tests was the contents of viscosity modifying agent (VMA), and the extrudability was quantitatively evaluated by measuring dimensions, distribution of aggregates, and surface quality of 3D-printed filaments. The test results showed that the dimensional suitability and surface quality were improved as the VMA contents were larger, and the coarse aggregates were evenly distributed in the section of filament regardless of the VMA contents. Based on the test results, the mix design process for concrete containing coarse aggregates for 3D printing has been proposed.