• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.32-32
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• 2015

Electrophoretic paint (E-paint) was investigated on four different magnesium substrates: as-extruded AZ61 (AZ61), heat-treated AZ61 (AZ61-H), as-extruded TZ61 (TZ61) and heat-treated TZ61 (TZ61-H), to elucidate the effect of heat treatment and alloying elements on the deposition and corrosion resistance of E-paint. It was found that, a rapid increase of voltage, indicating that the deposition of E-paint had started, was observed after an induction time of 0.39 min for AZ61-H, 0.43 min for AZ61, 0.51 min for TZ61-H and 0.58 min for TZ61. The amount of E-paint deposited on the four samples was approximately similar, but the electrical charge used for the deposition process on the heat-treated samples was smaller than that on the as-extruded samples. The current efficiencies of E-paint on AZ samples (AZ61 and AZ61-H) were higher than those of TZ samples (TZ61 and TZ61-H), and on the heat-treated samples were higher than on as-extruded samples. All E-paintings on the four magnesium substrates had an excellent adhesion without any paint detached by tape peel-test. However, many large blisters were formed on the surface of AZ samples, and none, or very small blisters were observed on TZ samples after immersion test in DI-water for 500 h at $40^{\circ}C$. Under salt spray test (SST) conditions, E-paint on AZ samples showed blistering adjacent to scribes, while blistering of E-paint occurred on intact areas of TZ samples. The E-paint on heat-treated samples showed much better corrosion resistance than that on as-extruded samples. The ranking of greater to lesser corrosion resistance of the E-paint on these four different magnesium substrates is indicated by the order: AZ61-H > AZ61 > TZ61-H > TZ61.

• 한방안이비인후피부과학회지
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• 제15권2호
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• pp.53-79
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth promoting effect was measured using hair growth index. As a result, Prunus mume, black bean, Brassica campestris subsp. black sesame and Rubi Fructus showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Prunus mume, Eriobotryae Folium showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of the effect of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT - PCR analyses were performed. However, there were no plant extracts, which have profound effect on the gene expression of several growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another tests for inhibition of microbial such as P. acne were also carried out to find whether these plant extracts have anti -microbial activities. Rubi Fructus showed anti -microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• 한방안이비인후피부과학회지
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• 제15권2호
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• pp.80-103
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth pormoting effect were measured using hair growth index As a result, Polygonum muitifiorum Thunb and Terrninalia chebula Retz. showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Morus alba L., Chaenomelis Fructus, Saussureae Radix, Angelicae Gigantis Radix, Polygonum multifiorum Thunb, and Angelica dahurica (Fischer) Bentham et Hooker f. showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of effects of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT-PCR analyses were performed. As a consequences, Mentha haplocalyx Briq., Cimicifuga foetida L., Eclipta prostrata (L.) L., Pinus densiflora S. et. Z, and Polygonum muitifiorum Thunb revealed the regulatory roles on the expression of growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another test for inhibition of microbial such as P. acne and P. ovale were also carried out to find whether these plant extracts have anti-microbial activities. Morus alba L. and Chaenomelis Fructus showed anti-microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• Computers and Concrete
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• 제34권2호
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• pp.247-265
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• 2024

Measuring the fracture toughness of concrete in laboratory settings is challenging due to various factors, such as complex sample preparation procedures, the requirement for precise instruments, potential sample failure, and the brittleness of the samples. Therefore, there is an urgent need to develop innovative and more effective tools to overcome these limitations. Supervised learning methods offer promising solutions. This study introduces seven machine learning algorithms for predicting concrete's effective fracture toughness (K-eff). The models were trained using 560 datasets obtained from the central straight notched Brazilian disc (CSNBD) test. The concrete samples used in the experiments contained micro silica and powdered stone, which are commonly used additives in the construction industry. The study considered six input parameters that affect concrete's K-eff, including concrete type, sample diameter, sample thickness, crack length, force, and angle of initial crack. All the algorithms demonstrated high accuracy on both the training and testing datasets, with R² values ranging from 0.9456 to 0.9999 and root mean squared error (RMSE) values ranging from 0.000004 to 0.009287. After evaluating their performance, the gated recurrent unit (GRU) algorithm showed the highest predictive accuracy. The ranking of the applied models, from highest to lowest performance in predicting the K-eff of concrete, was as follows: GRU, LSTM, RNN, SFL, ELM, LSSVM, and GEP. In conclusion, it is recommended to use supervised learning models, specifically GRU, for precise estimation of concrete's K-eff. This approach allows engineers to save significant time and costs associated with the CSNBD test. This research contributes to the field by introducing a reliable tool for accurately predicting the K-eff of concrete, enabling efficient decision-making in various engineering applications.

• 한국환경보건학회지
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• 제21권3호
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• pp.38-47
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• 1995

The Bioconcentration factor (BCF) is used as an important criterion in the risk assessment of environmental contaminants. Also it can be used as indicator of biomagnification of environmentally hazardous chemicals through food-chain as well as a tool for ranking the bioconcentration potential of the chemicals in the environment. This paper reports the measured BCF value on Chlorothalonil in Carassius auratus(goldfish), under steady state, and examined correlation between the BCF value and the partition coefficient or acute toxicity or physicochemical properties. Carassius auratus(goldfish) was chosen as test organism and test period were 3-day, 5-day. Experimental concentrations were 0.005, 0.01 and 0.05 ppm. Chlorothalonil in fish tissue and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detecting and quantitating of Chlorothalonil. Partition coefficient was determined by stir-flask method. $LC_{50}$ was determined on Chlorothalonil. Carbaryl and BPMC. The obtained results were as follows. 1. It was possible to determine short term BCFs of Chlorothalonil through relatively simple procedure in environmental concentrations. 2. $BF_3$ of Chlorothalonil in concentration of 0.005, 0.01 and 0.05 ppm were 2.1866$\pm$0.23446, 3.5269$\pm$0.23517, 10.2045$\pm$0.18053 and BCFs were 6.6543$\pm$0.55257, 6.9774$\pm$0.02500, 23.4576$\pm$2.06884, respectively. 3. Chlorothalonil concentration in fish extract and BCFs of Chlorothalonil were increased as increasing test concentration and prolonging test period. 4. Fate of test-water concentration on Chlorothalonil was greater than that of control-water con-centration. It is considered that greater fate of test-water concentration on Chlorothalonil is due to hydrolyzing nitrile group under the mild condition and substituting chloro group by some aromatic compounds in test water. 5. Determined logP of Chlorothalonil was 2.80. And determined $LC_{50}$ of Chlorothalonil in time of 24, 48, 72 and 96 hr were 0.1684, 0.1402, 0.1400, 0.1352(mg/l) respectively. And $LC_{50}$ of Carbaryl in above times were 19.918, 18.635, 18.466, 18.12(mg/l) respectively. $LC_{50}$ of BPMC were 10.248, 9.166, 9.087, 8.921(mg/l) respectively. 6. It is suggested that the BCF of Carbamates depend on partition coefficients. But BCF of Chlorothalonil, organochlorine pesticide, would be strongly influenced by steric, electronic effect of substituents than partition coefficient.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1696-1701
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• 2006

A random regression model was applied for the first time for the analysis of test day records and to study the genetic persistency of first lactation milk yield of Indian Murrah buffaloes. Wilmink's Function was chosen to describe the shape of lactation curves. Heritabilities of test day milk yield varied from 0.33 to 0.58 in different test days. The highest heritability was found in the initial test day ($5^{th}$ day) milk yield. Genetic correlations among test day milk yields were higher in the initial test day milk yield and decreased when the test day interval was increased. The magnitude of genetic correlations between test day and 305 day milk yield varied from 0.25 to 0.99. The genetic persistencies of first lactation milk yield were estimated based on daily breeding values using two methods. $P_1$ is the genetic persistency estimated as a summation of the deviation of estimated daily breeding value on days to attain peak yield from each day after days to attain peak yield to different lactation days. $P_2$ is the genetic persistency estimated as the additional genetic yield (gained or lost) from days to attain peak yield to estimated breeding value on different lactation days relative to an average buffalo having the same yield on days to attain peak yield. The mean genetic persistency on 90, 120, 180, 240, 278 and 305 days in milk was estimated as -4.23, -21.67, -101.67, -229.57, -330.06 and -388.64, respectively by $P_1$, whereas by $P_2$ on same days in milk were estimated as -3.96 (-0.32 kg), -23.94 (-0.87 kg), -112.81 (-1.96 kg), -245.83 (-2.81 kg), -350.04 (-3.28 kg) and -407.58 (-3.40 kg) respectively. Higher magnitude of rank correlations indicated that the ranking of buffaloes based on their genetic persistency in both methods were similar for evaluation of genetic persistency of buffaloes. Based on the estimated range of genetic persistency three types of genetic persistency were identified. Genetic correlations among genetic persistency in different days in milk and between genetic persistencies on the same day in milk were very high. The genetic correlations between genetic persistency for different days in milk and estimated breeding value for 305 DIM was increased from 90 DIM to 180 DIM, and highest around 240 DIM which indicates a minimum of 240 days as an optimum first lactation length might be required for genetic evaluation of Indian Murrah buffaloes.

• 응용통계연구
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• 제29권7호
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• pp.1411-1419
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• 2016

랜덤화 블록 계획법을 검정하는 비모수적 방법에는 일반적인 대립가설에서 Friedman (1937)이 제안한 검정법이 있다. 이 방법은 처리 효과의 차이를 알아보기 위한 검정법으로 블록 내 순위를 사용해 검정함으로써 블록 간 정보의 손실이 있을 수 있다. 본 논문에서는 Hodges와 Lehmann (1962)이 제안한 정렬방법을 이용하여 블록 간 정보 손실을 줄이고, Jo와 Kim (2013)이 제안한 랜덤화 블록 계획법의 결합위치 방법을 확장하여 결합위치에 점수함수를 적용한 새로운 비모수적 방법을 제시하였다. 또한 Monte carlo simulation을 통하여 기존의 검정 방법과 제안한 검정법의 검정력을 비교하였다.

• 한국항해항만학회지
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• 제29권10호
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• pp.897-906
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• 2005

본 논문의 목적은 우리 항만이 동북아 거점항만으로 변신하는데 필요한 항만배후부지전략을 도출하여 거점항만으로의 발전전략의 적합성을 분석하였다. 전략요인으로는 크게 개발정책방향, 개발방법론 및 부지조성전략요인으로 구분하여 분석하였다. 분석결과에 의하면, 부산항이 동북아 물류중심항만이 되기 위해서는 현재 진행 중인 항만배후부지가 실질적인 부가가치를 창출할 수 있도록 개발되는 것이 매우 중요한 것으로 나타나고 있다.

• 인지과학
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• 제6권3호
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• pp.65-81
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• 1995

복합명사는 한국어에서 가장 빈번하게 나타나는 색인어의 한 형태로서,영어권 중심의 정보검색 모델로는 다루기가 어려운 언어 현상의 하나이다.복합명사는 2개 이상의 단일어들의 조합으로 이루어져 있고,그 형태 또한 여러가지로 나타나기 때문에 색인과 검색의 큰 문제로 여겨져 왔다.본 논문에서는 복합명사의 어휘적 정보를 단위명사들의 통계적행태(statistical behavior)에 기반 하여 자동 획득하고,이러한 어휘적 정보를 검색에 적용하는 모델을 제시하고자 한다.본 방법은 색인시의 복합명사 인식의 어려움과 검색시의 형태의 다양성을 극복하는 모델로서 한국어를 포함한 동양권의 언어적 특징을 고려한 모델이다.

• 농촌계획
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• 제10권4호
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• pp.9-18
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• 2004

The purpose or this study is to simulate spatially the urban expansion phenomena with a cellular automata (CA) technique using GIS. A study area, Suwon city, was selected for test of model verification and application with the classified land-use maps of three data years: 1986, 1996, and 2000. The urbanized potential maps were generated with seven criteria of one geographic factor (slope of land), and six accessibility factors (time distances from city, national road, Seoul, station, and built-up boundary), considering their weighting values, which were optimized by WSM (weighted scenario method for intensity order) combined a ranking method and a AHP technique. The optimized weighting values at the urban expansion between 1986 and 1996 were applied to verify the CA model for the other expansion between 1996 and 2000. The results of model application showed that urban sprawl phenomena of the urban expansion toward rural area can be simulated spatially and temporally with several boundary conditions considering various scenarios for the criteria and parameters of the model. Ultimately, this study can contribute to reference data for land-use planning of urban fringe areas.