• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.743-749
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• 2010

This paper proposes a derating design method for improving system reliability by using a probabilistic approach. In the proposed design, the focus is upon system levels in determining derated levels of stresses such as temperature and current, unlike recent design approaches that focus on component levels. System reliability is evaluated using component reliability metrics that are given as functions of time and unknown stresses; this evaluation is based on a series system-reliability model. The variation in stress, which was not considered in previous derating designs, is introduced in the present design to account for the uncertainty in both environmental and operating conditions at the customer' hands. Optimization problems for system reliability improvement are formulated and solved using FORM to determine the best derating design. An example of a derating design for an electrical system shows the details of the proposed method and its applicability to systems design for reliability improvement.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.4 s.34
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• pp.59-65
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• 2005

It is very important to detect land cover/land use change from the past and to use it for future urban plan. This paper investigated the application of Landsat satellite imagery for detecting urban growth and assessing its impact on surface temperature in the region. Land cover/land use change detection was carried out by using 30m resolution Landsat satellite images and hierarchial approach was introduced to detect more detail change on the changing area through high resolution aerial photos. Also, surface temperature according to land cover/land use was calculated from Landsat TM thermal infrared data and compared with real temperature to analyze the relationship between urban expansion and surface temperature. As a result, the urban expansion has raised surface radiant temperature in the urbanized area. The method using remote sensing data based on GIS was found to be effective in monitoring and analysing urban growth and in evaluating urbanization impact on surface temperature.

• Journal of the Korean Society of Radiology
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• v.9 no.5
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• pp.287-293
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• 2015

Because of esophageal cancer has the long length of the lesion and also inhomogeneous in depth. So, the radiation dose distribution was inhomogeneous in radiation therapy. To overcomes the dose distribution uniformity using half beam method. Patient's CT image was used radiation treatment planning. We used two planning methods that one is the using normal beam and another is using half beam. Than comparing the two radiotherapy planning using target coverage, dose volume histogram, conformity index, homogeneity index and normal tissues - heart, spinal cord, lung -. In results, Treatment planning using half beam is little more than normal beam in target coverage, dose volume histogram, conformity index, homogeneity index and normal tissues covering. However, If the patient is not correct position patients may arise a side effect. Thus, the using in Half beam involving the geometrically exact under lung cancer is considered to advantage.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.235-243
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• 2020

Lumbar Lordosis Angle (LLA) is an index that can be used to evaluate the curvature of the lumbar vertebrae. It can measure the structural stability of the lumbar spine and the stability of each segment of the vertebral column at the intervertebral disc angle (IDA). Especially, our data shows it is found to be a strong positive correlation between obesity and the angle of lordosis for lumbar vertebrae. Also, the reason for the large IDA in the case of obesity seems to be the result of the weakening of anatomical structure as well as the gravity effect. And, the obesity interferes with normal sagittal balance and fails to maintain a straight posture with minimal energy. Therefore, the obesity can be an important factor in causing back pain by changing the lumbar lordosis.

• Journal of Gifted/Talented Education
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• v.17 no.2
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• pp.392-412
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• 2007

It has been understood that Confucian culture only blocks creative problem solving(CPS). However, it is claimed that Confucian culture exerts positive and negative influence on nurturing CPS. Confucian culture fosters CPS by urging strong motivation for learning, and building rich base of knowledge and skills in general and in specific domains through teaching joy of learning and hardworking fueled by parents' education fever. Confucian culture has negative influence on CPS with emphasis on obedience and conformity. Keju system, as a part of Confucian culture, resulted in excessive private tutoring to prepare for the high-stakes test, delimitation of students' experiences to matters to be tested, and students' weak interest, self-concept, and self-directed learning. Negative influence from Confucian culture on CPS is analyzed and some suggestions are provided for revising educational policies and educational practices in order to maximize the creative problem solving in Confucian countries.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.183-189
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• 2011

This paper suggests a user based OST(Open Street Traffic) system that solves TPEG's one-way communication problem, UTIS's limited usage and DSRC's small traffic bandwidth. In current commercial TPEG service, only some service providers collect traffic information. Thus, it can't cover traffic status in local lanes And UTIS, which local governments and police supports, requires additional equipments. Currently, only taxi and official vehicles use this system. Therefore, new traffic service by mobile device and user's participation can provide very detail traffic information coupling with previous traffic systems. But in this new system, real-time high volume data can be a problem. So, in this paper, new data storage manager design(TDSM :Traffic Data Storage Manager) is suggested and its performance is measured against commercial DBMS.

• Korean Security Journal
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• no.58
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• pp.155-176
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• 2019

The purpose of this study is to evaluate and analyze domestic private security activities through experiences of Chinese people who have been thought to be very necessary for the development of domestic private security and to suggest measures for the customization of foreigners and Chinese people for Korean private security companies. The purpose of this study was to analyze the psychological satisfaction of Korean civilian security activities through the experiences of Chinese Koreans who are using Korean civilian security services and to discuss ways to improve domestic civil security activities not only for Chinese Koreans but also for Koreans visiting Korea. And conducted in-depth interviews with limited data and insufficient prior research. First, we should not judge the scale of Chinese visit today as a separate industry that is not related to our private security. Second, it should be carried out confidently with a prepared marketing attitude that makes the choice of the security guard excellent. Third, a company management is necessary. Fourth, communication should be done. Fifth, it should become a loyal 'butle'.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.127-136
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• 2003

Posterolateral instability of the knee occurs more commonly in association with an injury to anterior and posterior cruciate ligament and combined injuries are severe injuries that result in significant functional instability and articular cartilage degeneration. Reconstruction of the anterior and posterior cruciate ligament without an appropriate treatment of posterolateral corner injury result in failure of the reconstructed cruciate ligaments. Meticulous physical examinations, imaging studies, lower limb alignment and gait pattern should be evaluated. Acute grade III isolated or combined injury of the posterolateral corner is best treated within three weeks by direct repair, or augumentation, or reconstruction. The appropriate surgical method or combined methods are selected among the several methods of posterior and posterolateal reconstruction, and all injuried posterolateral and cruciate ligament structures are anatomically reconstructed simultaneously or by stages. If a varus alignment and varus thrust is disclosed in chronic posterolateral instability of knee, soft tissue reconstructions laterally are highly unlikely to be able to correct tile problem. It is appropriate that valgus osteotomy should be done before soft tissue reconstruction and reevaluate the posterolateral instability about 6 months later.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.66-75
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• 2010

We proposed an occupant sensing system using single video camera and ultrasonic sensor for the advanced airbag. To detect the occupant form and the face position in real-time, we used the skin color and motion information. We made the candidate face block image using the threshold value of the color difference signal corresponding to skin color and difference value of current image and previous image of luminance signal to gel motion information. And then it detects the face by the morphology and the labeling. In case of night without color and luminance information, it detects the face by using the threshold value of the luminance signal get by infra-red LED instead of the color difference signal. To evaluate the performance of the proposed occupant detection system, it performed various experiments through the setting of the IEEE camera, ultrasonic sensor, and infra-red LED in vehicle jig.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.356-361
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• 2020

This paper presents a lightweight milli-scale crawling robot that can crawl on both sides, which was inspired by the movement of insects. This robot has an excellent ability to overcome obstacles, such as the narrow gaps and the rough terrain. In addition, the robot can crawl steadily and rapidly through triangular alternation, such as ants or cockroaches. The process of smart composite microstructures (SCM) was employed to make a lightweight robot structure. The SCM process replaced the conventional mechanical parts with flexure joints and composite links, which allows the weight of the robot to be reduced. In addition, the robot structure was robust against external impacts owing to the compliance of the constituent materials. Using the SCM process, the robot weighed only 32g with twelve legs in total on both sides. The robot showed a crawling speed of 0.52m/s on the front side and 0.42m/s on the backside.