• Fashion & Textile Research Journal
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• v.6 no.6
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• pp.810-814
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• 2004

This study is one of the fundamental researches for the development of future smart clothing and textile products using silver(Ag) nano powder. Our study was focused on the blocking or insulating effects of nano-processed textiles from electromagnetic waves. Also, for the surveying of the actual effect to human body, we measure the variation of electroencephalogram which is an indication of human physical symptoms. Among various textiles in this experiment, nano silver processed case has shown the best blocking performance from the electromagnetic waves, which decreases depending on the distance. As a reference model of working environment, we setup the visual stimuli object on the computer that is a source of electromagnetic wave. The power spectrum distribution and the incidence of electroencephalogram was measured. The analysed data has shown that, with nano-processed textiles, ${\beta}$ wave does not appear very often where ${\beta}$ wave appears only to illustrate the stable states of human's body. However, as for the materials without nano processing, the ratio of ${\gamma}$ waves in the total level of electroencephalogram becomes higher in spite of short exposure to visual stimuli in work environment, which shows that the worker becomes stressed. The ${\beta}$ wave electroencephalogram of all materials is drawn in calcarine fissure of occipital lobe to show the convergent distribution, and stronger with block-processed Nano Silver Silk(NSS). The study based on the potential risks of human diseases such as physical fatigue by electromagnetic waves, and has shown that the application of Nano Silver textile for human uses require a proper particle size of it which would not penetrate cellular tissues, and a proper binder and binding treatment for it. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.334-343
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• 1996

Quality evaluation for food and agricultural products have always been one of the most elusive problems associated with the handling , processing and marketing in a food plant production. In order to detect physical foreign materials in food and agricultural products, non-destructive techniques have been developed for many years. Application of X-ray system to detect physical foreign materials in food and agricultural products could be considered to be a high potential method. Especially , it is impossible to detect internal physical foreign materials by visual inspections. In this study, it was tried to be applied for two different X-ray devices. Soft X-ray system with CdTe sensor and X-ray CT scanner were evaluated for advantage of the detection of non-meltallic foreign materials in food and agricultural products . Though the soft X-ray is not a high energy radiation, it is possible to detect small different density in a material. The CdTe sensor has a high resolution for t e soft X-ray energy region. The density characteristics of foods and foreign material were expressed region. The density characteristics of foods and foreign materials were expressed as a soft X-ray energy spectrum. The energy spectrum was analyzed by a personal computer with a multi-channel analyzer. X-ray CT scanner can provide visual image and analyze by three dimensional information inside food and agricultural products. The X-ray CT scanner using as a medical equipment was used to detect a foreign material. The density characteristics of food and foreign materials in food were tried to be detected by the threshold value on the basis of the CT numbers. The soft X-ray absorption characteristics for acrylin plates and distilled water were obtained and could be found the possibility of detecting a small physical foreign materials such as a plastic wrapping film , a stone and grasshopper in food and agricultural products.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.113-123
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• 2011

The application of micro-simulation model has been extended farther with improvement of computer performance and development of complicated model. To make a micro-simulation model accurately replicate field traffic conditions, model calibration is very crucial. Studies on calibration of micro-simulation model have not been enough while lots of studies on calibration of macro-simulation model have been continued in our country. This paper presents an auto-calibration of parameter values in micro-simulation model(VISSIM) using genetic algorithm. RMSE(Root Mean Square Error) of collected volume on the urban expressway versus simulated volume is set as MOP(measure of performance) and objective function of optimization is set as to minimize the RMSE. Applying to urban expressway(Nae-bu circular) as a case study, it shows that RMSE of optimized parameter values decrease 60.4%($19.3{\longrightarrow}7.6$) compared to default parameter values and the proposed auto-calibration system is very effective.

• New & Renewable Energy
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• v.16 no.2
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• pp.35-46
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• 2020

Recently, turbines operating in hydro power plants are required to undergo renovation and modernization due to their age exceeding 30 years. In the process of renovation or modernization, a performance test of the scaled-down model is necessary to verify the performance of the real-size model. This model test method, with criteria that is similar to that of a real turbine, is the most economical and important method. Furthermore, the shapes of the runner and guide vane can be modified or replaced easily. However, during the process of modernization, the components with the spiral casing and draft tube are impossible to repair or replace because of the buried ground. Thus, in this study, numerical analysis is conducted to investigate the hydraulic performance based on the difference between the two-dimensional computer-aided design (CAD) shape and the real three-dimensional scan shape of the spiral casing and draft tube.

• The Mathematical Education
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• v.55 no.3
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• pp.357-382
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• 2016

The purpose of this study was to report the effects of self-directed and self-regulated learning programs on elementary, middle, and high school students through meta-analysis of previous studies. For this research, 22 of previous studies were selected which were all conducted in the country, and calculated the effect size of 'standardized change of the mean difference' for many factors included in each research. The findings were as follows: first, the overall effect sizes of self-directed and self-regulated learning programs on elementary, middle, and high school students were .665 and .702 in the affective and cognitive domain, respectively, meaning that the self-directed and self-regulated learning programs had average or greater effects on elementary, middle, and high school students and exerted somewhat greater effects in the cognitive domain. Second, when the areas of moderating effects were divided into self-directed and self-regulated learning, the former and latter had more influences on the cognitive and affective domains, respectively. Third, the elementary school level recorded a larger effect size both in the affective and cognitive domains than the secondary school level. Fourth, the findings show that the characteristics of affective domain, "reflective thinking" and "self-confidence," recorded a very large effect size both at the elementary and secondary school levels. Finally, the programs were more effective when the application period was one to four weeks in the affective domain and more than four weeks in the cognitive domain. And, Significance and implications of this research were discussed.

• Journal of Biosystems Engineering
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• v.27 no.6
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• pp.479-490
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• 2002

A dynamic model of a power shuttle transmission was developed and its validity was verified using the experimental data obtained from a transmission test bench. A 40㎾, 4WD tractor was also modeled using an application software EASY5 to investigate parameters and their effects on the power shifting performance. For a tractor model, the manual reverse gear was replaced by a power shuttle transmission. The tractor model also included an engine, main-gears for transmission, wheels, differentials and planet gears. Using the tractor model, the effects of the parameters such as modulating pressure and time, engine speed, tractor speed. tractor weight. reverse to forward speed ratio and torsional damper on the transient characteristics at starting and shuttle shifting were investigated by the computer simulation. The transient characteristics were represented by variations in clutch pressure, torque transmitted to input shaft and driving wheels, and power transmission capacity of the clutch. It was found that the modulating pressure and time affected most significantly the torque transmission and shifting time. The input torque, axle torque, power transmission capacity of the clutch and transmission time all increased with increase in engine speed, tractor speed. tractor weight and ratio of reverse to forward speeds. However, the axle torque decreased with tractor speed. Both the axle torque and power transmission capacity of the clutch also decreased with the ratio of reverse to forward speeds.

• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.2-9
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• 2002

Recently. VR( Virtual Reality) applications such as virtual studio and virtual character are wifely used In TV programs. and AR( Augmented Reality) applications are also belong taken an interest increasingly. This paper introduces a virtual screen system. which Is a new AR application for broadcasting. The virtual screen system is a real-time video augmentation system by tracking a chroma-patterned moving panel. We haute recently developed a virtual screen system.'K-vision'. Our system enables the user to hold and morse a simple panel on which live video, pictures of 3D graphics images can appear. All the Images seen on the panel change In the correct perspective, according to movements of the camera and the user holding the panel, in real-time. For the purpose of tracking janet. we use some computer vision techniques such as blob analysis and feature tracking. K-vision can work well with any type of camera. requiring no special add-ons. And no need for sensor attachments to the panel. no calibration procedures required. We are using K-vision in some TV programs such as election. documentary and entertainment.

• Korean Journal of Community Nutrition
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• v.15 no.6
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• pp.760-775
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• 2010

This study was performed to investigate the validity of food photographs for estimating individuals' dietary intakes and compare it with other dietary assessment methods. Subjects were 7 professors, 2 researchers, 12 dietitian and 16 graduate students majoring in food and nutrition. Among the subjects, 20 subjects had research experiences in the dietary intake survey more than one year while 17 had not. Each subject estimated 50 food portions displayed in computer monitor by comparing with standard food photographs, which were weighed portions of 28 foods from typical Korean diet. No significant differences between the estimated value and the weighed value of 17 (34%) food portions were shown in research-experienced group and those of 14 (28%) food portions were shown in no-researchexperienced group. 24-hour recall was the most frequently-used method for dietary assessment followed by in the order of food frequency questionnaire, dietary record, diet history and weighing method. After estimating food portions by photographs, 30 subjects (81%) were willing to use the method for dietary assessment because of its convenience and easy communication between researcher and subject. This study suggests that digital photography method would be a useful and convenient new instrument for estimating individuals' dietary intake. However, it is necessary to create standard database for food portions and carry out systematic education for food estimation in order to apply this method in the fields.

• Journal of Internet Computing and Services
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• v.3 no.1
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• pp.61-69
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• 2002

Big-bang growth of Internet and World Wide Web is supplying much information and resources to network. However, use of internet resources is receiving many limitations by bandwidth for most users. But, through Applet way, can solve degradation problem that follow on static side and bandwidth of CGI that HTML has. Mobile Agent starts in user's computer to accomplish user's specification purpose and achieves work rooving network. Because code that can perform so is transmitted, and is achieved in network through network, important problem happens to mobile code's security naturally. In computing environment that this research uses this Mobile Agent way that can protect host and agent groping report, describe problem that happen composing Mobile Agent relationship concept and Mobile Agent, and do so that may present method that is studying to solve these problem, and use method that application is possible actually among presented method and design transfer agent's security system.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.10
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• pp.491-498
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• 2005

The Denial of Service(DoS) attacks, which are done by consuming all of the computing or communication resources necessary for the services, are known very difficult to be protected from. TCP has drawbacks in its connection establishment for possible DoS attacks. TCP maintains the state of each partly established connection in the connection queue until it is established completely and accepted by the application. The attackers can make the queue full by sending connection requests repeatedly and not completing the connection establishment steps for those requests. In this paper, we have designed and implemented the extended TCP for preventing from SYN Flood DoS attacks. In the extended TCP, the state of each partly established connection is not maintained in the queue until the connection is established completely. For the extended TCP, we have modified the 3-way handshake procedure of TCP and implemented the extended TCP in the Linux operating system. The test result shows $0.05\%$ delay more than original TCP, but it shows that the extended TCP is strong for SYN Flood attacks.