• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.93-107
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• 2000

The excessive exposure to powered hand tools can cause damage to nerves, impair blood circulation, and musculoskeletal damage. The symptoms associated with hand-arm vibration syndrome (HAVS) include numbness, tingling, pain and subsequent reduced dexterity of the hands. This study was performed to report the prevalence of the HAVS and evaluate its related factors among the workers using powered hand tools. Total 282 workers in 11 plants of Kyungki and Inchon areas were examined. A standard symptom questionnaire was developed and administered to collect information on personal characteristics, work history, operating conditions, tool characteristics, and subjective symptoms of HAVS. Mean values (standard deviations) of the age, the duration of powered hand tools used, and the daily hours using powered hand tools were 38.3(8.9) years, 79.3(62.2) months and 6.0(2.6) hours, respectively. 132 workers(46.8%) showed vibration-induced white finger symptoms according to the Taylor-Pelmear classification, and 30 workers(10.6%) were interfered with the work. The results of a multiple logistic regression analysis controlling for age and daily working hours showed that smoking, work duration, weight of tools, and continuous work over 2 hours were significantly associated with the symptom of HAVS.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.443-446
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• 2014

Code reuse attack (CRA)는 기존의 코드 내에서 필요한 코드 조각들 (gadgets)을 모아 indirect branch 명령어들로 잇는 방식으로 공격자가 원하는 악성 프로그램을 구성할 수 있는 강력한 공격 방법이다. 공격자는 자신의 코드를 대상 시스템에 심는 대신 기존의 코드를 이용하기 때문에, 대부분의 범용 운영체제 (OS)가 강제하는 W^X protection 을 무력화할 수 있다. 이러한 CRA 에 대응하기 위하여 다수의 연구들에서 branch 의 trace 를 분석하여 CRA 고유의 특성을 찾아내는 Signature 기반 탐지 기술을 제안하였다. 본 논문에서는 ARM 프로세서 상에서의 CRA 를 대응하기 위한 Signature 기반 탐지 기술을 효율적으로 도울 수 있는 binary 분석 및 meta-data 생성 기술을 제안한다. 특히, 본 논문은 우리의 이전 논문에서 고려 되지 못했던 ARM 의 두 가지 명령어 세트의 특성을 고려하여, 공격자가 어느 명령어 세트를 이용하여 CRA 를 시도하더라도 막아낼 수 있도록 meta-data 를 두 가지 mode 에 대해서 생성하였다. 실험 결과, meta-data 는 본래 바이너리 코드 대비 20.8% 정도의 크기 증가를 일으키는 것으로 나타났다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.206-212
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• 2000

This paper presents a hybrid actuator scheme to actively control the end-point position and vibration of a two-link flexible robot arm. Control scheme consists of four different actuators; two servo-motors at the hubs and two piezoceramics bonded to the surfaces of the flexible links. Two sliding hyperplanes are designed for two servo-motors which have time varying parameters to maintain control performance in any configuration. The surface gradients of the hyperplanes are determined by pole assignment technique to guarantee the stability on the hyperplanes themselves. During the motion, undesirable oscillations caused by the torques based on the rigid link dynamics are actively suppressed by applying feedback control voltages to the piezoceramic actuators. Consequently, desired tip motion is achieved. In order to demonstrate the effectiveness of the proposed methodology, experiments are performed for the regulating and tracking control problems.

• Transactions of the Society of Information Storage Systems
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• v.2 no.1
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• pp.21-25
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• 2006

The new multimedia information environment requires smaller optical data storage systems. However, one of the difficulties encountered in designing small form factor(SFF) optical pick-up is to emit the heat which is generated from laser diode(LD). Heat generated at the LD can reduce the optical performance of the system and the lifetime of LD. Therefore, it is important to include the thermal design in the design stage of SFF optical pick-up system for high performance and the longer lifetime of LD, and furthermore, to analyze the thermal characteristics of LD in detail micro heat transfer analysis is necessary. In the present study, micro heat transfer analysis was performed using the finite element method for the $28{\times}11{\times}2mm^3$ super slim swing-arm type optical pick-up actuator for Blu-ray disk. Two different materials were used for a swing-arm; a double layer polycarbonate/steel structure and a single aluminum structure.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.175-181
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• 2015

In this paper, we develop a 2.4GHz ISM band wireless communication platform prototype based on embedded linux which support can be u-Hospital service. The developed system is available connecting between ARM920T processor board and FPGA board and linking IEEE 802.11b PHY board, AD/DA(10Bit) and RF(2.4GHz) board for wireless access. It is also can be utilized for the embedded system design with IEEE 802.11b/g Access Point(Option: IEEE 802.11a/b/g) test due to the Embedded Linux. Also, the developed system is possible to test and verify the radio access technology, Modem(OFDM etc) and IP(Intellectual Property) circuit. And make the most use of the system, we search for a expansion to that home and mobile healthcare, wellness service application.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.253-256
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• 2012

We present the IRC images of M51, a pair of interacting galaxies. Given the high angular resolution (7.4") and the wide field of view (~ 10') covering almost the entire M51 system, we investigate dust properties and their connection to the spiral arm structure. We have applied image-filtering processes including the wavelet analysis to the N3 image, which traces the total stellar mass best among the IRC bands. From this filtered image, the center, arm, and interarm regions are defined. A color, or flux ratio among the MIR bands, has been measured at each pixel (3.7" in size). We find a wide variety of S7/S11 with a difference between arm and interarm regions. We also find that at some positions S11 seems to be higher than predicted by MW dust models. Estimated contributions from the stellar continuum and gas emission lines to the band are not enough to explain this discrepancy. From these results, we deduce that the PAH ionization condition and its fraction to the total dust mass in M51 are different from those in MW.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.398-407
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• 2007

In this paper we proposed the tag antenna with a low performance distortion from an attached surface material using the asymmetric dual-arm dipole antenna(ADDA) structure. The tag is designed to exhibit low performance changes when the tag is attached on a target object(the medical litter receptacle, ${\varepsilon}_r=1.7,\;tan\;{\delta}=0.002$). Detail design parameters for the proposed antenna are optimized to maintain a good readable range in free-space as well as on a target object. The size of the optimized antenna is $100\;mm{\times}50\;mm$. The antenna shows the matching bandwidth($S_{11}$< -10 dB) of 3.7 % and the radiation efficiency of 80 % at the operating frequency. Finally we confirmed the readable range of the tag antenna by measurement and it shows about 5.3 m in free space and 5.5 m on the target object.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.9
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• pp.71-78
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• 2008

In this paper, we implement the H.264/AVC baseline decoder by hardware-software partitioning under the embedded Linux Kernel 2.4.26 and the FPGA-based target board with ARM926EJ-S core. We design several IPs for the time-demanding blocks, such as motion compensation, deblocking filter, and YUV-to-RGB and they are communicated with the host through the AMBA bus protocol. We also try to minimize the number of memory accesses between IPs and the reference software (JM 11.0) which is ported in the embedded Linux. The proposed IPs and the system have been designed and verified in several stages. The proposed system decodes the QCIF sample video at 2 frame per second when 24MHz of system clock is running and we expect the bitter performance if the proposed system is designed with ASIC.

• Applied Microscopy
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• v.38 no.4
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• pp.363-374
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• 2008

In this paper we have examined the usefulness of IWFR (the iterative wave-function reconstruction) analysis for through-focal series of high-resolution images for a relative thick crystal. In the work we employed JEOL ARM 1300S, and observed the high-resolution images for a Si crystal at the two orientations of [01-1] and [11-2] having 30 nm and 35 nm thickness respectively. As a result of applying IWFR method on the images we found out that even for a thick crystal by the method we can retrieve the exit-surface wave function. However because of the strong dynamical scattering effect, the image pattern of the function reflects only qualitatively the atomic column structure of the crystal examined. Nevertheless it is no doubt that the pattern would give important clue for the crystal structure.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.4
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• pp.11-20
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• 2015

Objectives The purpose of this study was to examine the relationship between cold hypersensitivity and bone mineral density. Methods 28 outpatients who visited OO University Oriental Hospital from July 11th, 2013 to August 28th, 2013 were analyzed. Patients were subjected to thermometer, and those with thermal difference greater than 0.3 ℃ between upper arm and palm and also with more than VAS 4 of cold hypersensitivity were diagnosed with cold sensitivity. Lumba spine (L2-4) and heel bone measurement were obtained on dual energy X-ray absorptiometry (DEXA) and Quantitative Computed Tomography (QCT). Results 1. There was statistically significant correlation between T-score of DEXA and body weight (0.522), BMI (0.643), OSTA (Osteoporosis elf-assesment Tool for Asians, 0.579), BMI, T-score and Z-score of QCT. OSTA and T-score of QCT (0.521) also had statistically significance. 2. There was no statistically significant correlation between body fat, abdominal obesity rate, degree of cold hypersensitivity, upper arm and palm's temperature difference, palm temperature, height and Z-score, T-score of QCT or T-sore of DEXA. Conclusions Bone mineral density was lower in women who had cold hypersensitivity of hand and feet. But there was no statistically significant correlation between bone mineral density and degree of cold hypersensitivity, upper arm and palm’s temperature difference.