• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.11
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• pp.1495-1506
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• 2004

This study was attempted to clarify the characteristics of elderly women's foot shape by examining the various measurements of women over 60 years old as compared with those of women in twenties considered as reference group. The subjects were 321 elderly women and 181 young women. Their right feet were measured directly and indirectly by using scanner and digital camera. The anthropometric measurements were composed of 62 items. They were measured during the months of July and August in 2001. As a result of comparing actual measurements of foot between the two groups, it was found that the elderly women tended to have shorter and lower foot than those among the young women. Among the elderly women, in addition, it was revealed that many deformities related to toes or legs led to the toes concentrated to the central axis of feet resulting in relatively steeper lateral angle of toe, and the heels and legs slanting forwards. As a result of comparing index values of foot between the groups, the elderly women's foot had the relatively wide width and low height in comparison with the length, showing more elliptical flattening than those of the young women. And, the width of the inside was wider than that of the outside, and the toe width was relatively short in comparison with the foot width resulting in severe deformities on the toes or the central axis of foot. Therefore, it was found that there were several deformities including flat foot or deformed toes among elderly women. It is expected that the characteristics of elderly women's foot shown in the results mentioned above will be used as the basic data in designing the footwear for elderly women.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.3
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• pp.23-30
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• 2002

In recently, using of steel reinforcements by reinforcing materials of the reinforced earth, micro-pile and root-pile etc,. is wide-spreading in the stabilizing control of cutting and embankment slopes, but the failure mechanism of reinforced earth as well as the effect of insert angles or types of reinforcement and others are not defined clearly. In this study, therefore heavy-duty direct shear tests were exercised on the reinforced soil and the non-reinforced soil, which was executed for research on the interaction of soil-reinforcement and theirs behavior. The hardness and softness and the standard sands were used for modeling of reinforced soil, the material constants for the computer simulation were estimated from the results of CD-Test. The effects of reinforcing and of friction increasing on the softness, area ratio of reinforcements is equal, were the better than them of the hardness, as well the reinforcing effects of shear strength without regard to the area ratio is much the same at $10^{\circ}$, insert angle of reinforced bar, differ from them of the existing study. Then, the results of numerical analysis showed that the behavior of reinforcements displayed bending resistance and shear resistance at $15^{\circ}$ and $30^{\circ}$, respectively. Also, the state of strain transfer was observed and the behavior of resistance mechanism on reinforcements presented almost the same them of landslides stabilizing pile.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.3
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• pp.279-288
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• 2012

The material removal mechanism in machining is significantly affected by the cutting edge geometry. Its effect becomes even more substantial when the depth of cut is relatively small as compared to the characteristic length which represents the shape and size of the cutting edge. Conventionally, radius or focal length has been employed as the characteristic length with the assumption that the shape of cutting edge is round or parabolic. However, in reality, there could be various ways to determine the radius or focal length even for the same tool edge profile, depending on the region to be considered as cutting edge in the measured profile and the constraints to be set in constructing the best fitted circle or parabola. In this regard, the present study proposes various models to determine the characteristic length in terms of radius or focal length. Their physical compatibility are validated by carrying out 2D orthogonal cutting experiments using inserts with a wide range of characteristic length ($30{\sim}180\;{\mu}m$ in terms of radius) and then by investigating the correlation between the characteristic length and the cutting forces. Such validation is based on the common belief that the larger the characteristic length is, the blunter the cutting edge is and the higher the cutting forces are. Interestingly, the results showed that the correlation is higher for the radius or focal length obtained with a constraint that the center of best fitted circle or the focus of the best fitted parabola should be on the bisectional line of the wedge angle of tool.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.150-157
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• 2015

Pedestrian detection has largely been researched as one of the important technologies for autonomous driving vehicle and preventing accidents. There are two categories for pedestrian detection, camera-based and LIDAR-based. LIDAR-based methods have the advantage of the wide angle of view and insensitivity of illuminance change while camera-based methods have not. However, there are several problems with 3D LIDAR, such as insufficient resolution to detect distant pedestrians and decrease in detection rate in a complex situation due to segmentation error and occlusion. In this paper, two methods using GM-PHD filter are proposed to improve the poor rates of pedestrian detection algorithms based on 3D LIDAR. First one improves detection performance and resolution of object by automatic accumulation of points in previous frames onto current objects. Second one additionally enhances the detection results by applying the GM-PHD filter which is modified in order to handle the poor situation to classified multi target. A quantitative evaluation with autonomously acquired road environment data shows the proposed methods highly increase the performance of existing pedestrian detection algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.116-122
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• 2016

This paper proposes a practical object shape reconstruction method using an underwater imaging sonar. In order to reconstruct the object shape, three methods are utilized. Firstly, the vertical field of view of imaging sonar is modified to narrow angle to reduce an uncertainty of estimated 3D position. The wide vertical field of view makes the incorrect estimation result about the 3D position of the underwater object. Secondly, simple noise filtering and range detection methods are designed to extract a distance from the sonar image. Lastly, a low pass filter is adopted to estimate a probability of voxel occupancy. To demonstrate the proposed methods, object shape reconstruction for three sample objects was performed in a basin and results are explained.

• Journal of Korean Neurosurgical Society
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• v.50 no.1
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• pp.11-16
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• 2011

Objective : The purpose of the present study was to determine the incidence of dural tears and predictable factors suggesting dural tears in patients who had lumbar burst fractures with vertical laminar fractures. Methods : A retrospective review was done on thirty-one patients who underwent operative treatment for lumbar burst fractures with vertical laminar fractures between January 2003 and December 2008. All patients were divided into two groups according to existence of dural tears, which were surgically confirmed; 21 patients with dural tears and 10 patients without dural tears. Clinical and radiographic findings were analyzed for their association with dural tears. Results : Among a total of 31 patients, dural tears were detected in 21 (67%) patients. A preoperative neurological deficits and mean separation distances of the edges in laminar fractures were found to be the reliable factors of dural tears (p=0.001 and 0.002, respectively). Decreased ratio of the central canal diameter and interpedicular distance were also the reliable factors suggesting dural tears (p=0.006 and 0.015, respectively). However, dural tears showed no significant association with age, sex, level of injury, absence of a posterior fat pad signal, the angle of retropulsed segment, or site of laminar fracture. Conclusion : Our study of lumbar burst fracture combined laminar fracture revealed that dural tears should be ruled out in cases of a preoperative neurological deficits, wide separation of the laminar fracture, severe canal encroachment, and wider interpedicular distance.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.317-321
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• 2009

Objective : In the thoracic spine, insertion of a pedicle screw is annoying due to small pedicle size and wide morphological variation between different levels of the spine and between individuals. The aim of our study was to analyze radiologic parameters of the pedicle morphometry from T1 to T8 using computed tomographic myelography (CTM) in Korean population. Methods : For evaluation of the thoracic pedicle morphometry, the authors prospectively analyzed a consecutive series of 26 patients with stable thoracic spines. With the consent of patients, thoracic CTM were performed, from T1 to T8. We calculated the transverse outer diameters and the transverse angles of the pedicle, distance from the cord to the inner cortical wall of the pedicle, and distance from the cord to the dura. Results : Transverse outer pedicle diameter was widest at T1 ($7.66{\pm}2.14\;mm$) and narrowest at T4 ($4.38{\pm}1.55\;mm$). Transverse pedicle angle was widest at T1 ($30.2{\pm}12.0^{\circ}$ and it became less than $9.0^{\circ}$ below T6 level. Theoretical safety zone of the medial perforation of the pedicle screw, namely, distance from the cord to inner cortical wall of the pedicle was more than 4.5 mm. Conclusion : Based on this study, we suggest that the current pedicle screw system is not always suitable for Korean patients. Computed tomography is required before performing a transpedicular screw fixation at the thoracic levels.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.202-208
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• 2001

A Switched Reluctance Motor(SRM) has double salient poles structure and the phase windings are wound in stator. SRM hase more simple structure that of other motor, thus manufacture cost is low, mechanically strong, reliable to a poor environment such as high temperature, and maintenance cost is low because of brushless. SRM needs position detector to get rotator position information for phase excitation and tachometer or encoder for constant speed operation. But, this paper doesn\`s use an encoder of high cost for velocity measurement of rotator. Instead of it, the algorithm for position detection and velocity estimation from simple slotted disk has been proposed and developed. To implement variable speed digital control system with velocity estimation algorithm, the TMS320F240-20MIPS fixed point arithmetic processor of TI corporation is used. The experimental results of the developing system are enable to control speed with wide range, not only single pulse, hard chopping mode and soft chopping, ut also variable speed control, and advance angle control.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.18-24
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• 2008

An organic light-emitting diode(OLED) has advantages of low power driving, self light-emitting, wide viewing angle, excellent high resolution, full color, high reproduction, fast response speed, simple manufacturing process, or the like. However, there are still a number of challenges to get over in order to put it to practical use as a high performance display. First of all, the most important thing is to improve the efficiency of the OLED element in order to commercialize it. To this end, its efficiency can be improved by lowering the driving voltage through the improvement of structure of the OLED element and the application of new organic substance. Therefore, in this study, we have manufactured a red OLED element by applying fluorescent dyes to the emitting layer of the element having the structure of ITO/TPD/ Znq2+DCJTB /Znq2/Al and the structure of ITO/CuPc/NPB/ Alq3+DCJTB/Alq3/Al, in order to light-emitting various colors or improve the brightness and the efficiency, and then we have evaluated its electrical and optical characteristics.

• Journal of Korean Foot and Ankle Society
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• v.10 no.2
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• pp.150-155
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• 2006

Purpose: The purpose of this study is to assess the results of the autologous osteochondral grafting harvested from medial side of talus for relatively large osteochondral lesion of the medial talar dome. Materials and Methods: From October 2004 to September 2005, 12 patients with osteochondral lesion measured more than 10 mm in axial MRI who were followed up more than 1 year after operation were analyzed. We evaluated postoperative symptoms by Mann and Reynolds scale, morbidity of donor site, and compared the range of both ankle motion. We also evaluated the union at the medial malleolar osteotomy site, trabecular connection between the grafted osteochondral mass and talus, irregularity of the articular surface in lesion. Results: Clinical results were rated as excellent in 4, good in 7, fair in 1. The mean angle of the total range of motion in affected ankle was decreased by 3 degrees compared to that in unaffected ankle. We did not observe abnormal findings at donor site. The osteotomized bone was united at mean 9 weeks (range, 8-12 weeks). We observed trabecular connection between grafted osteochondral mass and talus at mean 14 weeks (range, 12-16 weeks). We also observed irregular articular surface in osteochondral lesions in 6, smooth articular surface in 6. Conclusion: The local autologous osteochondral graft for relatively large osteochondral lesion of the medial talar dome is useful operative method with advantages of wide operative field, low morbidity of donor site, and high satisfaction rate.