• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.49-55
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• 2008

Arc welding process is one of the most important technologies to join metal plates. Robotic welding offers the reduced manufacturing cost sought, but its widespread use demands a means of sensing and correcting for inaccuracies in the part, the fixturing and the robot. A number of problems that need to be addressed in robotic arc welding processes include sensing, joint tracking, and lack of adequate models for process parameter prediction and quality control. Problems with parameter settings and quality control occur frequently in the GMA(Gas Metal Arc) welding process due to the large number of interactive process parameters that must be set and accurately controlled. The objectives of this paper are to realize the mapping characteristics of bead width using a sensitivity analysis and develop the neural network and multiple regression method, and finally select the most accurate model in order to control the weld quality(bead width) for fillet welding. The experimental results show that the proposed neural network estimator can predict bead width with reasonable accuracy, and guarantee the uniform weld quality.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.133-139
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• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.103-109
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• 2004

A virtual arthroscopy is a simulation of optical arthroscopy that reconstructs anatomical structures from tomographic images in joint region such as a knee, a shoulder and a wrist. In this paper, we propose a virtual arthroscopy based on isosurface raycasting, which is a kind of volume rendering methods for generating 3D images within a short time. Our method exploits a spatial data structure called min-max map to produce high-quality images in near real-time. Also we devise a physically-based camera control model using potential field. So a virtual camera can fly through in articular cavity without restriction. Using the high-speed rendering method and realistic camera control model, we developed a virtual arthroscopy system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.86-109
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• 2019

Cloud computing systems' performance is still a central focus of research for determining optimal resource utilization. Running several existing benchmarks simultaneously serves to acquire performance information from specific cloud system resources. However, the complexity of monitoring the existing performance of computing systems is a challenge requiring an efficient and interactive user directing performance-monitoring system. In this paper, we propose an effective multivariate control framework for monitoring cloud systems performance. The proposed framework utilizes the hardware cloud systems performance metrics, collects and displays the performance measurements in terms of meaningful graphics, stores the graphical information in a database, and provides the data on-demand without requiring a third party software. We present performance metrics in terms of CPU usage, RAM availability, number of cloud active machines, and number of running processes on the selected machines that can be monitored at a high control level by either using a cloud service customer or a cloud service provider. The experimental results show that the proposed framework is reliable, scalable, precise, and thus outperforming its counterparts in the field of monitoring cloud performance.

• Science of Emotion and Sensibility
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• v.18 no.4
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• pp.109-118
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• 2015

People tend to perceive their loved others (e.g., children, spouse, romantic partner) as their extended selves and then control over the loved others' fashion style corresponding to their self-concept. The study conceptually suggested that people's perceptions on legitimacy to interfere the others and their own fashionability would separately or interactively influence their control over the loved others' fashion style. To investigate the suggestions, an experiment with female participants in their 20's was conducted by using a scenario. The results indicated that participants' perception of legitimacy to interfere their boyfriends or their own fashionability did not have a separate effect on control over their boyfriends' fashion style. However, the legitimacy and the fashionability did have an interactive effect on the control. In particular, for high legitimacy groups, there was no difference in the control between low and high fashionability groups. For low legitimacy groups, the control was stronger in high fashionability group than in low fashionability group.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.194-203
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• 2011

This study investigated the effectiveness of visual biofeedback simulation training for patients with incomplete spinal cord injuries. Fifteen people with an ASIA impairment scale of C and D, according to the intervention method, were studied. They were randomly divided into two groups, seven people in the experimental group and eight people in the control group. They were studied three times a week for six weeks using a Tetrax Interactive Balance System, for a total of eighteen times, and each test took fifteen minutes. Paired t-tests were used to evaluate the changes before and after intervention. The difference between the groups was compared using an independent t-test. The experimental group showed significantly increased general stability, fall risk index, weight distribution (A, C, D, LEFT, HEEL) and weight distribution index, except for synchronization AC, BD. However, the control group only showed significantly increased weight distribution (A, C, LEFT). In a variation, experimental and control groups showed significantly increased weight distribution (A, B, C, HEEL), general stability, fall risk index and synchronization AD. Consequently, it was found that visual biofeedback simulation training was effective for the balance ability of incomplete spinal cord injury patients, and further studies are required.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.171-177
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• 2002

The Photovoltaic systems with solar cell way Provide electrical energy to the utility/consumers, which are becoming one of the promising energy substitutes. The photovoltaic system can be classified into two types : One is the stand-alone type, and the other utility interactive one. The latter can return the generated power to the utility, but the former can't. The utility interactive systems are so valuable for peak power cut in summer season. In the photovoltaic systems the maximum power point tracking (MPPT) has been studied for the increase of the generating energy of the photovoltaic system. There are many control methods of MPPT, but a new MPPT algorithm is proposed to overcome the disadvantages of the conventional ones, and as a result the proposed method enables to improve both tracking ability and generating efficiency of photo voltaic system without DC chopper.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3805-3808
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• 2013

Background: Osteosarcomas have many established risk factors, both genetic and environmental, but by themselves these explain only part of the total cancer incidence. Bisphenol A (BPA) is an environmental estrogen associated with risk of several kinds of tumour. The lysyl oxidase gene (LOX) may also contribute to risk of tumours including osteosarcomas. Here, we investigated possible interactions of BPA and a LOX polymorphism on the risk of osteosarcoma. Method: The present hospital-based case-control study included 106 cancer patients and 112 controls from a Chinese population. Internal burden of BPA exposure was assessed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) method. Genotypes were determined using PCR-RFLP methods. Results: Compared with those in low BPA exposure group, subjects with BPA more than or equal to median value had significant increased risk of osteosarcoma among subjects who carried GC or CC genotypes. A significant interaction with BPA level and the -22G/C polymorphism was observed for osteosarcoma overall, osteosarcoma affecting knee and osteosarcoma affecting hip, as $P_{forinteraction}$ = 0.036 for osteosarcoma overall; $P_{forinteraction}$ = 0.024 for osteosarcoma affecting knee; and $P_{forinteraction}$ = 0.017 for osteosarcoma affecting hip. Conclusions: The results suggest that BPA exposure interacts with the -22G/C polymorphism of the LOX gene to increase the risk of osteosarcoma.

• Journal of The Korean Association For Science Education
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• v.20 no.3
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• pp.468-478
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• 2000

In this study, the effects of a teaching strategy based on interactive formative assessment on students' science concept understandings and science-related attitudes were investigated. Students' perceptions toward this teaching strategy were also examined. Eight classes chosen from a co-ed middle school in Seoul. Four classes were assigned to the experimental group and the other four classes were assigned to the control group. After the instructions, tests regarding students' conceptions and science-related attitudes were administered. We also interviewed 24 students randomly chosen from the experimental group to investigate their perceptions toward the teaching strategy used. The results showed that the teaching strategy used was more effective for enhancing students' science concept understandings. However, there was no significant difference in science-related attitudes between the two groups. For the experimental group, no significant differences were found in the gain scores of the conceptions tests between the subgroups by previous achievement or cognitive levels. From interviews, it was found that students thought that the teaching strategy used encouraged much interactions and motivated them to think, and that teacher's appropriate feedbacks were helpful to their understanding scientific concepts.

• Nutritional Sciences
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• v.8 no.4
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• pp.256-261
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• 2005

Although nutrition education for pregnant women is important, few such programs have been carefully examined from the participants' perspective in Korea. Focus groups were used to identify 1) perceived eating behaviors during pregnancy and lactation, 2) factors associated with healthy eating behaviors, and 3) needs for nutrition education programs. Using a trained moderator, we conducted 7 focus group interviews with 44 pregnant women over a four-month period. Focus group discussions were video - and audio - taped, transcribed and categorized by major themes. Participants expressed interest in receiving nutrition education regarding healthy eating, weight control after delivery, weaning foods and health management, yet they showed little interest in breastfeeding. The majority of them said that meal balance and meal regularity were the most important components of good health during pregnancy. They were less likely to be confident about taking dietary supplements, including Oriental medicines. life stress and poor appetite associated with pregnancy were major barriers to healthy eating habits during pregnancy. The most important sources of nutrition and health information were friends and family members, especially those who had become pregnant recently. Qualified educators and reliable information appeared to be the most important aspects of program development. Regarding types of nutrition education, participants tended to prefer a combination of individual counseling and small group education with hands-on materials and interactive formats. The use of Web-based nutrition education was well received Major concerns about Web-based nutrition education were authenticity, tailored messages and interactive formats for sharing information. These results offer useful information for designing nutrition education programs for pregnant and lactating women in Korea for health promotion.