• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.113-122
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• 2009

The domestic construction market started to expand steadily since 1970s. The building market which utilizes a sandwich panel with advantages of economical construction expenses and convenient construction has grown rapidly in recent years. However, the companies which specialize in constructing sandwich panels are relatively small or medium size, compared with other construction companies. As a result, studies on the improvement of productivity have not been conducted sufficiently. In this study, the construction sites of sandwich panel are investigated, and the work processes by each team are analyzed. Additionally, the productivity and the construction cost of each work group are analyzed by constructing a model using the Web-Cyclone. It analyzed sensitivities about change of productivity and work costs following in processing place of the panel which is one of the productivity effect factors, so it assayed the optimized productivity by each work group and work costs. Analysis showed that 30% of productivity has improved compared with the factory processing work group, and analysis of work costs showed that about 15% of work costs was increased. Also sensitivity analysis of opening ratio showed that the work costs optimization will be accomplished when about 20% of opening was processed from the factory.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.157-164
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• 2008

In order to raise efficiency in construction, construction period, construction costs etc. that have been problematic in the methods of hydration heat reduction thus far, this study has developed a new method. The principle of the developed construction method involves the laying of a heat conducting medium such as the heat pipe in the concrete, and through the fast conduction of heat by the heat pipe, the hydration heat occurring within the mass concrete is transferred to the exterior by which the internal hydration heat is reduced. If the study results of the onsite test are summarized, on application of existing hydration heat reduction methods, the highest temperature was reached in about 2$\sim$4 days, but when the heat pipe of this study was used, the period was reduced to within 24 hours. Moreover, when the thermal crack index was calculated with the method using the heat pipe as developed in this study, a value of 1.2 or higher was revealed, which is a level that can restrict the occurrence of cracks. Therefore, when the hydration heat control method using the heat pipe as developed in this study is applied, not only the effects of construction efficiency and reduction in construction period, but also outstanding economical effects can be expected.

• Journal of Energy Engineering
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• v.16 no.4
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• pp.170-180
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• 2007

This paper deals with the economy of scale for domestic on-site hydrogen stations fueled with natural gas and naptha. We evaluate the economic feasibility of on-site hydrogen stations with hydrogen production capacities of $30Nm^3/hr,\;100Nm^3/hr\;and\;300Nm^3/hr$. We build a classical economic feasibility model and we make some sensitivity analyses by changing the values of input factors such as the hydrogen sale price and the discount rate. The estimated hydrogen prices of steam methane reforming stations with production capacities of $30\;Nm^3/hr,\;100\;Nm^3/hr\;and\;300\;Nm^3/hr$ are 18,472 won/kg, 10,689 won/kg and 7,758 won/kg, respectively. Also, the hydrogen prices are about the same if we use naptha as a raw material for hydrogen energy instead of natural gas. It turns out that small and medium size domestic on-site hydrogen stations will not be economical in the near future. This indicates that we need to construct large scale on-site hydrogen fueling stations even for the initial phase of the hydrogen economy.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.871-878
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• 2004

Pulsed electric fields(PEF) technology is one of the latest nonthermal methods of food processing for obtaining safe and minimally processed foods. This technology can be effectively explored for obtaining safe food with minimum effect on nutritional, flavor, rheological and sensory qualities of food products. The process involves the application of high voltage(typically 20 ${\sim}$ 80 kv/cm) to foods placed between two electrodes. The mode of inactivation of microorganism; by PEP processing has been postulated in term; of electric breakdown and electroporation. The extent of destruction of microorganisms in PEF processing depends mainly on the electric field strength of the pulses and treatment time. For each cell types, a specific critical electric field strength and specific critical treatment time are required depending on the cell characteristics and the type and strength of the medium where they have been present. The effect also depends on the types of microorganisms and their phase of growth. A careful combination of processing parameters has to be selected for effective processing. The potential applications of PEF technology are numerous ranging from biotechnology to food preservation. With respect to food processing, it has already been established that, the technology is non-thermal in nature, economical and energy efficient, besides providing minimally processed foods. This article gives a brief overview of this technology for food processing applications.

• Korean Security Journal
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• no.16
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• pp.119-135
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• 2008

This study is concerned on how much effect to activate private security officers from the attitude of CEO in private security companies. Of course the philosophy of CEO at the work is much important element on the company activity. And in small-medium size private security company the effect of CEO is tremendous because most of decision making comes from CEO and company is operated. The result of the analysis of the survey on the CEO in private security business is as belows. a) Most of them are not satisfied and negative from current situation of private security industry because too many companies are scattered and the expected social understanding is too low even though the company was established by their own decision due to it was fit to their aptitude. b) The job position is estimated not high by socio-economical perspective, which would be improved to get higher because this industry is very future business. c) Most of members of the korea security association are in negative on the policy of the korea security association but to enhance of the activity all the members should be in union. d) Must make and settle down a channel to communicate and cooperate each other between public and private sector of security business.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.670-676
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• 2009

Bankruptcy of firms in Korea can cause distress of financial institutions because these institutions have disterssed bond. Accordingly, social and economical spill-over effects by these results are very big. Even after the difficult times of IMF crisis had ended, bankruptcy of information-based small-medium companies and venture firms listed on the KOSDAQ has been continued. In this context, this study developed and adopted failure prediction models for which discriminant analysis was used. Samples of this study was 81 firms respectively for both failed and non-failed firms listed on the KOSDAQ between the year of 2000 and 2007. The results of this study are as follows. First, the accuracy of classification of the model by years was $74.5%{\sim}76.5%$, and the accuracy of classification of the mean model was $69.6%{\sim}80.4%$. Among the models, the mean model of -one year, -two years, and -three years was highest in accuracy of classification (80.4%). Second, accuracy of prediction of final model adopted on validation samples showed 85% before one year of bankruptcy. The results of this study may be significant in that the results may be used as early warning system for bankruptcy prediction of KOSDAQ firms.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.151-156
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• 2011

Previously most of flood prevention efforts have been made for relatively large watersheds near to channel flow. However, as economical development and the expansion of leisure areas to mountainous region, human casualty by flash flood occurs frequently, requiring additional prevention activity. Therefore, to reduce the damage of human lives and property by flash flood, we develop an assessment method for flash flood occurrence for mountainous areas considering various factors involving it. PROMETHEE(Preference Ranking Organization METHod for Enrichment Evaluations) which is one of the MCDM(Multi-Criteria Decision Making) was adopted to assess the contribution of each factor to the risk of the flash flood in the mountainous area. The main evaluation criteria are classified into three categories, namely, the regional and rainfall characteristics, and geographical features. Also, the Entropy method is used to determine the weight of each evaluation criteria without survey. The suggested method based on PROMETHEE with Entropy method is applied to BongHwa region to verify its applicability. After applied, the method successfully assesses the relative risk of flash flood occurrence of each sub region in the BongHwa region. Out of the seventeen sub-regions, five, seven and five of them are evaluated as high-risk, medium-risk, and low-risk, respectively. To verify the results, we searched the historical data of flash flood and the flash flood had occurred in one of high-risk sub-regions at 2008.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.55-61
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• 2021

In this study, microbes were collected before and after disinfection using ANIOS(ANIOSURF Premium NPC) and compared the areas where the radiological technologist and the patient frequently contacted the chest X-ray. From September 1st to September 7th, 2020. in P Hospital in Deagu, 4 region were collected in a 10×10 size using a sterile cotton swab of the transport medium, and before and after disinfection results were obtained through the colorimetric method. As a result, n the X-ray tube handle Proteus mirabilis, Staphylococcus epidermidis, Bacillus spp., Candida spp., and in the Chin region Proteus mirabilis, Enterococcu faecium, Pseudomonas aeruginosa, NTM, and in the Chest region Proteus mirabilis, Enterococcu faecium, Pseudomonas aeruginosa, and in the Palm region NTM, Candida spp. were detected, and 103 CFU(Colony Forming Unit) or more were measured. After disinfection, only X-ray tube handle was detect Bacillus spp. and more than 102 CFU was measured. Microorganisms found prior to disinfection can cause opportunistic infections, Experimental results showed that Aniosulf(0.25%) is more economical and disinfectant than ethanol(70-90%) and isopropyl alcohol(70-90%). However, further research is needed on the detection of Bacillus spp. resultingly this research is useful basic data of infection control in Radiography room and prevention secondary infections.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.207-219
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• 2021

Several additives are used to enhance the geotechnical properties (e.g., shear wave velocity, shear modulus) of soils to provide sustainable, economical and eco-friendly solutions in geotechnical and geo-environmental engineering. In this study, piezoelectric ring actuators are used to measure the shear wave velocity of unreinforced, fiber, cemented, and fiber reinforced cemented Toyoura sand. One dimensional oedometer tests are performed on medium dense specimens of Toyoura sand-cement-fiber-silica flour mixtures with different percentages of silica flour (0-42%), fiber and cement (e.g., 0-3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of silica flour, fiber and cement additives. Results show that with the addition of 1-3% of PVA fibers, the shear wave velocity increases by only 1-3%. However, the addition of 1-4% of cement increases the shear wave velocity by 8-35%. 10.5-21% increase of silica flour reduces the shear wave velocity by 2-5% but adding 28-42% silica flour significantly reduces the shear wave velocity by 12-31%. In addition, the combined effect of cement and fibers was also found and with only 2% cement and 1% fiber, the shear wave velocity increase was found to be approximately 24% and with only 3% cement and 3% fibers this increased to 35%. The results from this study for the normalized shear modulus and normalized mean effective stress agree well with previous findings on pure Toyoura sand, Toyoura silty sand, fiber reinforced, fiber reinforced cemented Toyoura sand. Any variations are likely due to the difference in stress history (i.e., isotropic versus anisotropic consolidation) and the measurement method. In addition, these small discrepancies could be attributed to several other factors. The potential factors include the difference in specimen sizes, test devices, methods of analysis for the measurement of arrival time, the use of an appropriate Ko to convert the vertical stresses into mean effective stress, and sample preparation techniques. Lastly, it was investigated that there is a robust inverse relationship between α factor and 𝞫₀ exponent. It was found that less compressible soils exhibit higher 𝜶 factors and lower 𝞫₀ exponents.

• The Korean Journal of Franchise Management
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• v.3 no.1
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• pp.92-110
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• 2012

Due to the social problems including recent economic crisis and unemployment rate increase, the demand of business foundation market has been increased and, in the meantime, on the basis of the business foundation support policy of the government including youth foundation support policy and Small & Medium Business Administration foundation planning, business foundation market has been showing steady growth trend. With this enlargement of foundation market, as the accompanied increase of franchise market is expected, it is considered that the importance of more realistic and concrete research about franchise market be larger than before. This study considered brand image, main office support, foundation cost, information search activity as the advanced variable of effect on brand selection and established the cause of effect on brand selection by improving the existing advanced research, and its result is as follows. First, according to foundation business kind, age, sex, yes or no of marriage, there is some difference III the thought about brand image and foundation possibility. Second, Second, the most important factor of franchise contract intention is economical specificity. It is difficult to consider brand image, franchise support and information search activity as the property having a big effect on preliminary founder, and it was shown that the cost for franchise management(Consistency with initial foundation cost and self-capital, promotion cost, management fund, facility/equipment reinvestment, etc.) is an important property. Specially, it was shown that consistency with initial foundation cost and self-capital is the most important factor for preliminary founder.