• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.1
• /
• pp.63-71
• /
• 2011

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. But most of by-products is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. In this study, we investigated the influence of alkali activator and superplasticizer on the flowability and compressive strength of the alkali-activated mortar in oder to develop cementless alkali-activated concrete using blast furnace slag. In view of the results, we found out that the type and mixture ratio of alkali activator, the type and adding order of superplasticizer results to be significant factors. When cementless alkali-activated mortar using blast furnace slag manufactured with 1:1 the mass ratio of 9M NaOH and sodium silicate, and added superplasticizer before alkali activator in the mixer, we can be secured workability with 180 mm of flow during 1 hours and compressive strength of about 50 MPa under $20^{\circ}C$ curing condition at age of 28days.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.9
• /
• pp.31-37
• /
• 2013

In this study installation diameter, interval, area replacement ratio and ground hardness of applicable ground in C.G.S method should be mastered through surrounding ground by conducting modeling. Optimum artificial neural network was selected through the study of the parameter of artificial neural network and prediction model was developed by the relationship with numerical analysis and artificial neural network. As this result, C.G.S pile settlement and ground settlement were found to be equal in terms of diameter, interval, area replacement ratio and ground hardness, presented in a single curve, which means that the behavior pattern of applied ground in C.G.S method was presented as some form, and based on such a result, learning the artificial neural network for 3D behavior was found to be possible. As the study results of artificial neural network internal factor, when using the number of neural in hidden layer 10, momentum constant 0.2 and learning rate 0.2, relationship between input and output was expressed properly. As a result of evaluating the ground behavior of C.G.S method which was applied to using such optimum structure of artificial neural network model, is that determination coefficient in case of C.G.S pile settlement was 0.8737, in case of ground settlement was 0.7339 and in case of ground heaving was 0.7212, sufficient reliability was known.

• Korean Chemical Engineering Research
• /
• v.55 no.2
• /
• pp.201-213
• /
• 2017

Water is removed from crude oil containing water by using oil separator. This study aims to develop a three-dimensional (3D) Eulerian computational fluid dynamics (CFD) model to predict the separation efficiency of air-water-oil separator. In the incompressible, isothermal and unsteady-state CFD model, air is defined as continuous phase, and water and oil are given as dispersed phase. The momentum equation includes the drag force, lift force and resistance force of porous media. The standard k-${\varepsilon}$ model is used for turbulence flow. The exit pressures of water and oil play an important role in determining the liquid level of the oil separator. The exit pressures were identified to be 6.3 kPa and 5.1 kPa for water and oil, respectively, to keep a liquid level of 25 cm at a normal operating condition. The time evolution of volume fractions of air, water and oil was investigated. The settling velocities of water and oil along the longitudinal separator distance were analyzed, when the oil separator reached a steady-state. The oil separation efficiency obtained from the CFD model was 99.85%, which agreed well with experimental data. The relatively simple CFD model can be used for the modification of oil separator structure and finding optimal operating conditions.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.8 no.3
• /
• pp.27-37
• /
• 2013

In recent, Korean government TF Team announced new entrepreneurship policy of establishing virtuous cycle in high-tech venture startup financing ecosystem with emphasizing on 'boosting up angel investment and M&A.' This policy is brought not only to come up with the previous policy defects of creating less creative starts-up despite that government has put die-hard efforts, such as big chunk of budget dumping and policy preference, to promote high-tech starts-up since the year of 1997, but also to found right momentum of shifting entrepreneurship policy paradigm from government-direct to entrepreneur into indirect via utilizing the market forces. In particular, this policy puts a highlight on promoting angel investment, representing unfolding red carpets for creative economy. However, this policy confront critical fatal flaws such as a serious lacks of business angels which carry out the core function of government policy. In worse off, business angels cannot be raised up in short term period by taking other practical entrepreneurship ecosystem cases. As alternative, this paper propose the raising-up over entrepreneurship facilitators with having angel investing potentials in short term. In specific, this paper suggest the training methodology over the previous BI manager, passive simple angel investors, and consultants in entrepreneurship for embedding entrepreneurship facilitators. This paper carries four different specific studies. First, this paper implement literature review for entrepreneurship policy with respect to evaluating the previous entrepreneurship policies and making a diagnosis over its consequences. Second, it carries theoretical literature reviews relating to Korean angel investment and business incubation. Third, it proposes the concept of entrepreneurship facilitators. Fourth, it brings the alternatives of raising up entrepreneurship facilitators.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.2
• /
• pp.585-594
• /
• 2013

In this study, laboratory experiments and numerical simulations were conducted to test the performance of resonance power buoy system proposed by Kweon et al.(2010). The system is composed of a linear generator and a mooring buoy. The mover of the linear generator mainly has heave motion driven by vertical oscillation of the buoy. In this system, the velocity discrepancy between the mover and the buoy makes electricity. However, ocean wave energy as a natural resource around Korean peninsula is comparatively small and the driving force for producing electricity is not enough for commercialization. Therefore, it is necessary that the buoy motion be amplified by using resonance characteristics. In order to verify the resonance effects on the test power buoy, the experimental investigations were conducted in the large wave flume (length of 110 m, width of 8 m, maximum depth of 6 m) equipped with regular and random plunger wave generator. The resonance draft of test power buoy is designed for the corresponding period of incident wave, 1.96 sec. Regular wave test results show that the heave response amplitude operator(RAO) by a test buoy has the amplification of 5.66 times higher compared to the wave amplitude at the resonance period. Test results of random waves show that the buoy has the largest spectrum area of 20.73 times higher at the point of not the resonance period but the shorter one of 1.85 sec. Therefore this study suggests the resonance power buoy for wave power generation for commercial application in the case of the coastal and oceanic area with smaller wave energy.

• Management & Information Systems Review
• /
• v.32 no.1
• /
• pp.289-309
• /
• 2013

Social enterprise has moved from periphery to take center stage. Social enterprises are a truly global phenomenon and associated with solving social problems with business approaches. While the numbers of social enterprises have grown and their impact is likely to continue to do so, it would be dangerous to assume that the revolutionary momentum will automatically continue, because social enterprise faced sustainability challenges. This study collected the data from directory of Korean Social Enterprise to conduct a quantitative research on the growth of social enterprise in South Korea. This study conducted longitudinal analysis of 491 social enterprise certified between 2007 and 2010, of economic performance with financial index and social impact with employment structure. Though global financial crisis, Korean social enterprises show that there is a considerable increase in all of quantitative and qualitative aspects. Korean social enterprises have provided meaningful work to those normally excluded from the labour market and tried to raise their life of working. In the future, Korean social enterprises should find a way to balance social and financial performance and ensure the sustainability of the business.

• The Korean Journal of Mycology
• /
• v.41 no.3
• /
• pp.142-148
• /
• 2013

Sorghum (Sorghum bicolor Moench) was traditionally grown on a small scale, however, at present its cultivation is getting momentum in terms of food and animal feed crop throughtout the Korea. Grain mold symptoms of the plant were frequently observed during disease surveys in Korea from 2007 to 2009. The symptoms were highly variable. Severely infected grain was fully covered with mold and partially infected grain may look normal or discolored. Ninety isolates of Fusarium species were obtained from the diseased plants collected from several locations in the country. Among the collected Fusarium isolates, 41 were identified as Fusarium thapsinum, 23 as F. proliferatum, 12 as F. graminearum, 5 as F. incarnatum, and 3 as F. equiseti based on their morphological and cultural characteristics. Elongation factor 1 alpha gene sequences of the isolates were used for phylogenetic analysis. Analyses of the sequences revealed that the isolates were confirmed to be identical with related species of NCBI GenBank. Pathogenicity tests showed that three dominant species, F. thapsinum, F. proliferatum and F. graminearum were strongly virulent to grains of sorghum. This study is the first report of sorghum grain mold caused by Fusarium species in Korea.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.1
• /
• pp.17-24
• /
• 2011

The characteristics of flow and strength of CLSM depend on the combination ratio including the fly ash, pond ash, cement, water quantity and etc. However, it is very difficult to draw the mechanism about the flow, strength and the mixing ratio of each components. Therefore, the method of calculation drawing the flow about the component ratio of CLSM and compression strength value is needed for the valid practical use of CLSM. To verify the efficiency of artificial neural network, new data which were not used for establishing the model were predicted and compared with the results of laboratory tests. In this research, it was used to evaluate the learning efficiency of the artificial neural network model and the prediction ability by changing the node number of hidden layer, learning rate, momentum, target system error and hidden layer. By using the results, the optimized artificial neural network model which is suitable for a flow and compressive strength estimate of CLSM was determined.

• Korean Journal of Health Education and Promotion
• /
• v.18 no.1
• /
• pp.61-78
• /
• 2001

The purpose of this research was to find out plans to promote the fulfillment of the breast self-examination and breast cancer screening, which is preventive health behavior about women's having breast cancer exam in some part of our country with searching for the primary causes which have an effect on their fulfillment. The subjects of the study were 540 literate volunteers who were of age from 20 to 69 and who visited 8 health centers in Taegu. The survey research was made through questionares in the 8 health centers in Taegu from the 15th to the 30th of September, 1998. Based on Becker's health belief model asking medical staff's opinions with bibliographies, the major findings from the survey was as follow. The fulfillment rate of the breast self-examination and the breast cancer screening was 37.8％(204 subjects), 27.6％ (149 subjects) each. Getting breast self-exam varied significantly depending on subject's age, income of family, religion, occupation and the number of children. As far as the breast cancer screening was concerned, there was remarkably significant difference in accordance with their age, marital status, religion, occupation, income of family, the number of children, ways of nursing and parturition age of the first baby. The subjects in their forties accounted for the highest rate. Based on the fulfillment of the breast self-examination and the breast cancer screening, the average points of all the variables presented from the health belief as well as the points of the susceptibility, seriousness, benefits, knowledge and level of health concern of interest in health were significantly higher than the points of non-fulfillment of them in the statistical analysis whereas the barriers was lower than them. In consequence of the multiple-logistic regression analysis putting the breast self-examination and the breast cancer screening in dependent variables, occupation, knowledge, seriousness, benefits, barriers and cues to action had significant effects on breast self-examination against breast cancer. Looking more attainments, thinking diseases more seriously, feeling more usefulness and there being any patient around with breast cancer led to the higher rate of the breast self-examination against it. On the other hand, feeling more impedition as well as housewives caused the lower rate of it. The breast cancer screening was significantly affected by age, sensitivity, usefulness, impedition and behavior momentum as well. The cases who are older, feeling more sensitivity against breast cancer, more usefulness of the examination and where any patient around, the fulfillment rate was higher. Contrarily the more impedition they felt, the lower the fulfillment rate was. Accordingly, the study of the causes, which have significant effects on the fulfillment of the self-examination and the breast cancer screening in order to find it in an early stage, and the development of health education programs as well as proper education for public health through carrying on campaigns and stepping up public relations must be indispensable.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.6
• /
• pp.749-754
• /
• 2011

In this study, we propose the design of optimized pRBFNNs-based face recognition system using two-dimensional Image and ASM algorithm. usually the existing 2 dimensional face recognition methods have the effects of the scale change of the image, position variation or the backgrounds of an image. In this paper, the face region information obtained from the detected face region is used for the compensation of these defects. In this paper, we use a CCD camera to obtain a picture frame directly. By using histogram equalization method, we can partially enhance the distorted image influenced by natural as well as artificial illumination. AdaBoost algorithm is used for the detection of face image between face and non-face image area. We can butt up personal profile by extracting the both face contour and shape using ASM(Active Shape Model) and then reduce dimension of image data using PCA. The proposed pRBFNNs consists of three functional modules such as the condition part, the conclusion part, and the inference part. In the condition part of fuzzy rules, input space is partitioned with Fuzzy C-Means clustering. In the conclusion part of rules, the connection weight of RBFNNs is represented as three kinds of polynomials such as constant, linear, and quadratic. The essential design parameters (including learning rate, momentum coefficient and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. The proposed pRBFNNs are applied to real-time face image database and then demonstrated from viewpoint of the output performance and recognition rate.