• Journal of the Korean GEO-environmental Society
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• v.8 no.5
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• pp.47-55
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• 2007

The increment of impermeable land area due to widespread land development caused the adverse impact on urban disaster prevention because it could decrease the peak rate of runoff as well as increase the runoff and peak flow during rainy period. To date, little research has been conducted on the infiltration characteristics and quantitative analysis because of their highly dependence on construction method, paving material, surface permeability, and field condition. Hence, this study was performed to investigate the infiltration characteristics of runoff-reducing facilities according to the type of paving material, which were examined using experimental apparatus with varying paving material and rainfall intensity, and thus to provide fundamental research data for runoff-reducing infiltration facilities. In this study, the infiltration characteristics were examined under the rainfall intensity of 20, 30, 50, 80, 100, 200 mm/hr for a variety type of paving materials such as concrete, asphalt, sand, grassland, and permeable paving material. The infiltration rate for permeable paving material was observed to be more than 93% under the condition of less than 200 mm/hr of rainfall intensity. For the compacted earth and grassland, the ultimate infiltration rate was estimated to be about 13% to 67%. The permeable paving material was concluded to be the most appropriate one for the runoff-reducing infiltration facilities because it has more favorable advantages than others in the light of infiltration volume, disaster prevention, and river training.

• Composites Research
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• v.23 no.4
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• pp.44-51
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• 2010

Recently, to solve the problems associated with the neutralization and corrosion of reinforced concrete compression members, the structural configurations such as CFFT (Concrete Filled GFRP Tube) and RCFFT (Reinforced Concrete Filled GFRR Tube) have been developed and applied to main members of civil engineering structure. These members can increase structural performance in terms of structural stability, ductility as well as chemical resistance compared with conventional concrete structural members. Many researches in numerous institutions to predict the load carrying capacity of the concrete compression member strengthened with FRP materials have been conducted and they have been suggested an equation for the prediction of the load carrying capacity of the members. Through the review of the research results, it was found that their results are similar each other. Moreover, it was also found that the results are not directly applicable to our specimens since the results are largely depended upon the member configurations. Also, since the accurate design criteria for the RC members strengthened with FRP such as RCFFT have not been established properly, relevant theoretical and experimental investigations must be conducted for the application to the practical structures. In this study, structural behavior of RCFFT was evaluated through compressive and quasi-static flexural tests in order to formulate design criteria for the structural design. In addition, the RCFFT members were also investigated to examine their confinement effect and the equations capable of estimating the compressive ultimate strength and flexural stiffness of the RCFFT members were proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.248-258
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• 2020

This study proposed a breakdown structure for maintenance and management technologies under the concept of comprehensive asset management at the life cycle level of infrastructure based on benchmarking with other developed countries. For this purpose, a comparative case study was performed to review and analyze the existing definitions and hierarchies for infrastructure maintenance, repair, and rehabilitation (MR&R) systems under major industrialized countries and South Korea. In accordance with the ratio of maintenance costs to GDP, the U.S., U.K, and Japan were selected to review their systems. The classifications and definitions of MR&R technologies under the laws were analyzed. The result showed that most developed countries differentiate maintenance and repair from improvement and constitute a system centered on preventive maintenance activities. On the other hand, Korea's system for facility management is not definitely classified and still focused on reactive structures, which need to be improved. In this study, as proposed, a breakdown structure established the concept of Maintenance and Management, Maintenance & Repair, and Performance Improvement. Consequently, this study could be used as the basis for the implementation of preventive MR&R activities and reasonable resource allocations from an asset management point of view.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.897-904
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• 2005

Face Recognition has been an active research area because it is not difficult to acquire face image data and it is applicable in wide range area in real world. Due to the high dimensionality of a face image space, however, it is not easy to process the face images. In this paper, we propose a method to reduce the dimension of the facial data and extract the features from them. It will be solved using the method which extracts the features from holistic face images. The proposed algorithm consists of two parts. The first is the using of principal component analysis (PCA) to transform three dimensional color facial images to one dimensional gray facial images. The second is integrated linear discriminant analusis (PCA+LDA) to prevent the loss of informations in case of performing separated steps. Integrated LDA is integrated algorithm of PCA for reduction of dimension and LDA for discrimination of facial vectors. First, in case of transformation from color image to gray image, PCA(Principal Component Analysis) is performed to enhance the image contrast to raise the recognition rate. Second, integrated LDA(Linear Discriminant Analysis) combines the two steps, namely PCA for dimensionality reduction and LDA for discrimination. It makes possible to describe concise algorithm expression and to prevent the information loss in separate steps. To validate the proposed method, the algorithm is implemented and tested on well controlled face databases.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.479-485
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• 2010

To handle container effectively is one of the most important factors in a port because working time is linked soon into cost. Since the middle of 1990s, RMGC(Rail-Mounted Gantry Crane) and RTGC(Rubber-Tired Gantry Crane) have been developed and widely used to operate containers in the yard. The RTGC is more difficult than RMGC in the automatic control system design. Although, the RTGC is largely advantaged to free driving environment, it has some considerable disadvantages in the system operating. In general, the problems are due to tire slip and lack of tire pressure etc. Therefore, a desirable research result has not been shown in this time. So, in this paper, we propose a new approach to design tracking control system for the RTGC in which the mathematical modeling is included. From the simulation results, the control performance of the designed control systems is evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.629-635
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• 2019

In this study, we analyzed the effect of FAN and oil cooler application on APU. MIL-STD-810 was applied to the atmospheric environment and radiation dose in order to perform thermal flow analysis. The heat flow was analyzed for the case in which the inlet / outlet fan was applied (Case 1), the case in which the inlet fan and the oil cooler were applied (Case 2), and the case in which the inlet / outlet fan and the oil cooler were applied (Case 3). As a result, it was confirmed that the cylinder head temperature of Case 3 was 21.4 times lower than that of Case 1 and 8.0 times lower than that of Case 2. Experiments were conducted under the same ambient conditions in order to examine the validity of the results. The numerical values and experimental results showed a difference of less than 7%. Through this, we were able to confirm that the APU heat flow optimization model satisfies the design conditions. The results of this study are expected to be used as basic data for optimizing heat flow of APU.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.49-56
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• 2020

High temperature heat generated during rifle firing not only degrades the performance of the weapon, but also limits the user's operation. In this study, temperature change of handguard according to firing was measured with reference to Human Engineering criteria and the operability according to material was examined. Accordingly, for the firing test, three types of Korean rifle and one overseas model were selected for each material of handguard, and firing test was conducted using a contact type temperature meter. The test result shows that using a plastic handguard with low thermal conductivity and aluminum handguard with high thermal conductivity enabled the rifles to be operated with bare hands even when firing at more than 100 rounds at low atmospheric temperature. However, when firing more than 60 rounds at over 20℃ atmospheric temperature, aluminum handguard use is limited. When firing quickly over 100 rounds, handguard use is restricted regardless of its fabrication material. To eliminate operational limitations by overheating, it is necessary to eliminate direct contact with skin using gloves, vertical grips, etc. This study examined the operability of rifles in terms of thermal risk, and the resulting study results are expected to be used as basic data for Human Engineering of other rifles and munitions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.604-609
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• 2020

There are various methods of finishing concrete surfaces, and when considering workability, the spray method is effective, but rebound occurs. The allocation of rebound occurrence control should be adjusted according to the materials used. Thus, a basic study was conducted on multiple techniques for reducing the rebound incidence that are suitable for surface finishing materials containing a photocatalyst. A prior study derived the reduction effect and optimal mix ratio for photocatalytic performance. Based on that study, the rebound reduction was verified according to the specifications of the content and the mechanical durability characteristics of the mixed materials. Rebound, compressive strength, flexural rigidity, and table flow tests were done. The flow was fixed at 170±10 mm considering the workability of the mortar spray equipment. For the experimental variables, the rebound number was adjusted to the silica sand variables relative to the cement weight, and silica sands No. 5 and No. 7 were used. The results show the highest compression strength in the final S-1 variable, and the amount of rebound was minimized. These results were sufficiently filled with the bindings of the silica pores, which increased the binding force between the aggregates, resulting in a lower amount of rebound.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1491-1497
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• 2005

This study evaluates the antioxidant capacity of 40 varieties of colored barley and hulled barley. For investigation of the antioxidant capacity as well as the contents of anthocyanin, color intensity, total phenolic acids contents, SOD-like activity, samples were extracted in ethanol with 0.1$\%$ TFA. The content of anthocyanin was measured spectrophotometrically. The total phenolic acid content was analyzed by using th Folin-Ciocalteu method, and the color intensity was determined by using the color difference meter. The results showed that in the anthocyanin content and color intensity of colored barley there were significant differences according to their varieties. The resulting concentration levels were divided into three groups: Group I (high) Group II (medium), and Group III (low). In the measurements of antioxidant capacity significant differences(P < 0.05) were found among varieties in those groups. Colored barley was higher in electrondonating capability, SOD-like activity, iuhibitory effects on lecithin oxidation, and hydrogen radical- scavenging ability Meanwhile, from different antioxidant tests, No. 26, 27, 34, and 35 varieties measured high in antioxidation ability fell into Group I high in the anthocyanin content. This results suggest that the anthocyanin content has a significant relationship on antioxidant activity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6C
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• pp.251-258
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• 2011

Steel pipe piles have been used as various deep foundation materials for a long time. Recent increase in steel material cost has made engineers reluctant in using it even with its good quality and ease of construction. Therefore when constructing with steel pipe pile, the decision to reuse the excessive pile length that is cut off from the designed pile head elevation after pile driving can be cost saving. This has caused many constructors to reuse the pile leftovers with new piles, but the absence of quantitative structural capacity behaviors of steel pipe pile after pile driving or appropriate countermeasures and standards in reusing steel pipe pile has resulted in wrong applications, pile structural integrity problems, inappropriate limitation of reusable pile length, etc. The structural performance analysis between a new pile and a pile that has undergone working state and ultimate state stress level during pile driving was performed in this research by means of comparing the results between the dynamic pile load test, tensile load test, charpy energy test and fatigue test for high strength steel of $440N/mm^2$ yield strength. Test results show that under working load conditions the yield strength variation is less than 2% and for ultimate load conditions the variation is less than 5% for maximum total blow count of 3000. The results have been statistically analyzed to check the sensitivity of each factors involved. From the test results, reusability of steel pipe pile lies not in the main pipe yield strength deviation but in the reduction of absorb energy, strength changes and quality control at the welded section, shape deformation and local buckling during pile driving.