• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.1
• /
• pp.87-95
• /
• 1996

A new design scheme for the fuzzy pattern matching classifier (FPMC) is proposed. in conventional design of FPMC, there are no exact information about the membership function of which shape and number critically affect the performance of classifier. So far, a trial and error or heuristic method is used to find membership functions for the input patterns. But each of them have limits in its application to the various types of pattern recognition problem. In this paper, a new method to find the appropriate shape and number of membership functions for the input patterns which minimize classification error is proposed using genetic algorithms(GAs). Genetic algorithms belong to a class of stochastic algorithms based on biological models of evolution. They have been applied to many function optimization problems and shown to find optimal or near optimal solutions. In this paper, GAs are used to find the appropriate shape and number of membership functions based on fitness function which is inversely proportional to classification error. The strings in GAs determine the membership functions and recognition results using these membership functions affect reproduction of next generation in GAs. The proposed design scheme is applied to the several patterns such as tire tread patterns and handwritten alphabetic characters. Experimental results show the usefulness of the proposed scheme.

• Journal of the Korean earth science society
• /
• v.22 no.1
• /
• pp.65-74
• /
• 2001

To evaluate the influence of meteorological conditions on the performance of DOAS (Differential Optical Absorption Spectroscopy) system, we analyzed the concentrations of three criteria pollutants and relevant environmental parameters measured during 14 month periods between Jun. 1999 and Oct. 2000. According to our study, the performance of DOAS can be sensitively influenced via various manners (such as among different chemicals and/or between different time periods). It turns out that O$_3$ exhibits most frequently the weakest agreement between two systems. When comparison was made among different meteorological parameters, the strongest variability was seen from such ones as windspeed, wind direction, and irradiance. In addition, the absolute differences in measured concentrations between two systems were compared against various environmental parameters by means of linear regression analysis. Results of this analysis indicated that the differences between the two tend to decrease with the increase of such parameters as windspeed. It is thus concluded on the basis of our study that the simultaneous evaluation of meteorological data should be an essential step toward the accurate assessment of pollutant concentration data obtained by DOAS measurement system.

• Journal of the Korean Geotechnical Society
• /
• v.31 no.10
• /
• pp.37-47
• /
• 2015

Recently, the quality of drilled shafts concrete has been improved significantly due to the improved concrete performance, upgraded concrete materials, and better management of on-site constructions. Despite the development, current conventional quality management on concrete constructions is still used without any criticism. In this study, compressive strength test results of more than 200 concrete specimens after 7 and 28 days of curing were collected from one site at Songdo area of Incheon. The concrete specimens were prepared from the concrete with aggregate maximum dimensions of 25 mm, target compressive strength of 40 MPa, and slump of 180 mm. Influential factors including concrete temperature, air temperature, amount of slump, amount of air, amount of salinity on concrete specimen were also examined. The database was established from collected information and statistical analyses were performed. Analyzed results confirm that "the difference between concrete temperature and air temperature" has the largest impact on the compressive strengths of specimens at the durations of 7 and 28 days.

• Journal of the Korean GEO-environmental Society
• /
• v.8 no.5
• /
• pp.47-55
• /
• 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
• /
• v.23 no.4
• /
• pp.44-51
• /
• 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
• /
• v.21 no.10
• /
• pp.248-258
• /
• 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
• /
• v.9 no.4
• /
• pp.897-904
• /
• 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
• /
• v.34 no.6
• /
• pp.479-485
• /
• 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
• /
• v.20 no.12
• /
• pp.629-635
• /
• 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
• /
• v.21 no.9
• /
• pp.49-56
• /
• 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.