• The Journal of Korean Physical Therapy
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• v.3 no.1
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• pp.151-174
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• 1991

The purpose of this study is to research the actual conditions of industrial accident patients and to produce worker satisfaction and a rational and effective counter measure plan. Direct interviews with 179 cases (in and out patients) were carried out during a three month period from April to July 1990, at six hospitals : two general hospitals Sun Lin and Sung Mo in Po Hang, and four general hospitals in Taegu : Kyung pooh University Hospital, Dong San Medical Center, Young Nam Medical Center and Catholic Hospital. The results of this study are summarized as fellows : 1. Among the 179 cases, $51.6\%$ were male and $48.4\%$ were female. The two largest age groups were 30-39, $31.8\%$ and 20-29, $27.4\%$. Among the 179 cases, $51.6\%$ were married, the largest family number was 2 to 3, $41.1\%$ and 4 to 5, $25.6\%$. Educationally, graduation from high school was the largest group, $46.4\%$ among ,the patients, followed by middle school and primary school. The largest group income level was from 40-69 만원, $45.2\%$. The largest group of patients who worked over 50 hrs. a week was $52.0\%$. The largest group of patients who worked less than 1 year was $44.7\%$, of the patients in work places of less than 100 people, $60.3\%$ were injured and in work places of 100-299 people, $20.1\%$ were injured. In manufacturing, the largest group injured was $55.3\%$, the next group was transport, storage, communication. The largest group of production workers injured was $40.2\%$. 2. The cause of injury in the largest group was facility problems, $33.5\%$. The next group was unsafe habits, $30.2\%$ ; a lack of safety knowledge, $17.9\%$ ; and insufficient supervision, $12.3\%$. The 30-39 year age group head the highest number of injuries, $40.4\%$ ; work places with more than 10 years of work, $44.4\%$ ; work places with more than 1000 people, $56.3\%$ and mining accidents, $80.0\%$. Among. these groups the highest cause of injury was due to facility problems. 3. The accident pattern showed machinery injuries $28.5\%$ as the largest group, followed by falls & falling objects $17.3\%$, fire & electric $15.1\%$, strucke by an object $14.5\%$, followed by overaction and vehicular accidents. The accident pattern showed $46.4\%$ among workers over the 50 year age group, workers in the 5-10 year group, $50.0\%$ ; places employing more than 1000 workers, $35.3\%$ ; construction $73.7\%$, and construction workers $57.1\%$, among these fall & falling objects caused the greatest number of injuries. 4. The largest group of injuries was fractures $54.8\%$, trauma $14.5\%$, amputation $11.7\%$, open wound, and burns. The largest number of fractures occurred in people in the 30-39 year age group, $63.2\%$ : over 10 years of work, $55.0\%$ ; in work places of 300-490 people, $63.6\%$ ; construction $63.2\%$ and general workers $57.2\%$. 5. The largest group of injuries was upper extremity $45.3\%$, lower extremity $24.0\%$, trunk $18.5\%$ and head or neck $12.2\%$. Of these groups, upper extremity injuries were the highest in those less than 20 years old $75.0\%$, less than 1 year or work $59.5\%$, in work places of 500-999 people $60.0\%$, manufacturing $56.6\%$ and production workers $55.6\%$. 6. Periods of injury showed 34 people injured in September, to be the largest followed by October, 32 ; August, 22 people : July, 19 people and the lowest December, 2 people. During the week, Friday had the largest group injured, 35 people ; followed by Saturday, 26 people and the lowest was Wednesday, 17 people, During the day 1400 hours had the largest group injured, 38 people ; followed by 800 hours, 31 people. 7. On a basis of 5 as the highest mark, the average, according to worker satisfaction showed facility safety 3.55, work environment 3.47, income 3.44, job 3.21 and treatment 2.98. 8. The correlation between general characteristics and injury showed that age was directly correlated to the duration of work (r=2591) p<0.01, age was directly correlated to industry (r=2311) p<0.01, and the duration was directly correlated to occupation (r=4372) p<0.001.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.171-175
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• 2006

In this paper, we have developed a retrodirective active array operating in the 2 GHz LS band. The retrodirective array has the property of redirecting any electromagnetic wave back to the incoming direction without any priory informations. The system is integrated with phase conjugators and antenna array. Microwave phase conjugators can be implemented by microwave mixers. In this research, 2-port gate mixers using pHEMT and $1{\times}4$ monopole array have been used to achieve the retrodirectivity. The measured results have been compared with the theoretical prediction, and it has been shown that there exists a reasonable agreement between them. The monopole array can be used easily in many areas for simplicity and cost-effective property, and the retrodirective array developed in this research can be applied directly in the base station facilities for the wireless mobile communications. indoor wireless LAN and RFID transponders.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.37-43
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• 2009

This paper describes a monolithic Darlington-cascade amplifier (DCA) operating at X-band, realized with a 0.35-micron SiGe bipolar process, which provides 45 GHz $f_T$. A conventional cascade amplifier was also designed on the same process and tested to establish a reference. Compared to the reference cascade amplifier, the proposed monolithic amplifier circuit exhibits an improved gain of 2.5 dB and improved output power 1-dB compression point of 5.2 dB with 72% wider bandwidth. Measurement results show 19.5 dB gain, 11.2 dBm 1-dB compression power, and 3.1 GHz bandwidth. These results demonstrate that the Darlington-cascade cell is an advantageous substitute to the conventional cascade amplifier.

• Health Policy and Management
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• v.17 no.4
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• pp.82-98
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• 2007

This study aimed to analyze the factors that influence the job satisfaction of nurses involved in medical insurance reviews. The study involved a self-administered questionnaire survey which was conducted with to 297 nurses who were in charge of medical insurance reviews between April 10 and April 28, 2000. The average job satisfaction of the subjects was 3.04. The sub-items of job satisfaction were noted to be high for 'professional status'(3.79) and low for wage (2.46). The job satisfaction of subjects showed statistically significant differences with regard to education, career, and volume of service(p<0.05). The average job stress of subjects was 2.57. The sub-items of job stress included problems pertaining to human relationships problem(2.84), conflicts with doctors at work (2.79), and the burden of excessive workloads(2.79), in that order. Multiple regression analysis demonstrated that job satisfaction was significantly low when the job stress was higher. It also showed that the job satisfaction was significantly high as there was more frequency of judgements and higher education. These results suggest that the job stress of nurses involved in medical insurance reviews has a profound impact on their job satisfaction. Therefore, the efforts should be made to reduce their job stress. It may also be beneficial to reinforce the training with the doctors and nurses in order to improve their communication skills. Disseminating more information about insurance standards may also be considered.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.393-396
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• 2004

본 논문에서는 완충층용 MgO 박막을 P-type(100)Si 기판위에 작업가스 $Ar:O_2=80:20$, RF 파워 50W, 기판온도 $400^{\circ}C$, 10mtorr의 작업진공에서 $500{\AA}$ 증착하였다. 제작된 MgO/Si 기판위에 RF Magnetron sputtering법으로 작업가스 $Ar:O_2$의 비율을 90:10, 80:20, 70:30으로 변화하면서 $BST(Ba_{0.5}Sr_{0.5}TiO_3)$ 박막을 약 $2000{\AA}$ 증착하였다. XRD 측정결과 작업가스비의 변화에 관계없이(110)BST와 (111)BST 피크만이 관찰되었으며 작업가스 $Ar:O_2=80:20$에서 가장 양호한 결정성을 나타내었다. I-V 측정결과 인가전계 ${\pm}100kV/cm$에서 $10^{-7}A/cm^2$이하의 양호한 누설전류 특성을 보여주고 있으며 C-V 측정결과 작업가스 $Ar:O_2$의 비율 90:10, 80:20, 70:30에서의 비유전율은 각각 283, 305, 296으로서 작업가스비 80:20에서 제작된 박막의 특성이 가장 우수하였다. 작업가스비 80:20에서 제작된 박막의 SEM 측정결과 결정이 성장되었음을 확인할 수 있었고 그레인의 크기는 약 10nm였다.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.436-440
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• 2021

The impact of the gate length (L_g) on the DC and high-frequency characteristics of indium-rich In_0.8Ga_0.2As channel high-electron mobility transistors (HEMTs) on a 3-inch InP substrate was inverstigated. HEMTs with a source-to-drain spacing (L_SD) of 0.8 ㎛ with different values of L_g ranging from 1 ㎛ to 19 nm were fabricated, and their DC and RF responses were measured and analyzed in detail. In addition, a T-shaped gate with a gate stem height as high as 200 nm was utilized to minimize the parasitic gate capacitance during device fabrication. The threshold voltage (V_T) roll-off behavior against L_g was observed clearly, and the maximum transconductance (g_{m_max}) improved as L_g scaled down to 19 nm. In particular, the device with an L_g of 19 nm with an L_SD of 0.8 mm exhibited an excellent combination of DC and RF characteristics, such as a g_{m_max} of 2.5 mS/㎛, On resistance (R_ON) of 261 Ω·㎛, current-gain cutoff frequency (f_T) of 738 GHz, and maximum oscillation frequency (f_max) of 492 GHz. The results indicate that the reduction of L_g to 19 nm improves the DC and RF characteristics of InGaAs HEMTs, and a possible increase in the parasitic capacitance component, associated with T-shap, remains negligible in the device architecture.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1062-1070
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• 2022

In the present communication, pure and stable α-Bismuth Oxide (Bi₂O₃) nanoparticles (NPs) were synthesized by low temperature solution combustion method using urea as a fuel and calcined at 500℃. The synthesized sample was characterized by using powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible absorption spectroscopy. The PXRD pattern confirms the formation of mono-clinic, stable and low temperature phase α-Bi₂O₃. The direct optical energy band gap was estimated by using Wood and Tauc's relation which was found to be 2.81 eV. The characterized sample was studied for X-ray/gamma ray shielding properties in the energy range 0.081-1.332 MeV using NaI (Tl) detector and multi channel analyzer (MCA). The measured shielding parameters agrees well with the theory, whereas, slight deviation up to 20% is observed below 356 keV. This deviation is mainly due to the influence of atomic size of the target medium. Furthermore an accurate theory is necessary to explain the interaction of X-ray/gamma ray with the NPs.The present work opens new window to use this facile, economical, efficient, low temperature method to synthesize nanomaterials for X-ray/gamma ray shielding purpose.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.27-34
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• 2013

Most of existing biomedical signal measurement devices measure and evaluate biomedical signal only in a single device. Also, even if the device is multi-functional, those biomedical signals can be measured by selection of the user. In this paper, we implemented wristband-style biomedical signal measurement device for u-healthcare system to solve the problem above. Implemented device uses 4 infrared sensors to measure the pulse, 2 electrodes to measure the skin conductivity, and 3-axis accelerometer to measure momentum. Also, we propose a communication packet frame for transmitting biomedical signal data to PC or mobile device, using Zigbee. Studies show that our device has the error rate of less than twice for pulse measurement, 85.6%, 84.7% reliability for momentum measurement, and the skin conductivity has changed according to the user's physical status.

• Imaging Science in Dentistry
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• v.32 no.4
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• pp.201-206
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• 2002

Purpose : To evaluate the radiographic change of operation sites after orthognathic surgery using the digital image processing and fractal analysis. Materials and Methods : A series of panoramic radiographs of thirty-five randomly selected patients who had undergone mandibular orthognathic surgery (bilateral sagittal split ramus osteotomy) without clinical complication for osseous healing, were taken. The panoramic radiographs of each selected patient were taken at pre-operation (stage 0), 1 or 2 days after operation (stage 1), 1 month after operation (stage 2), 6 months after operation (stage 3), and 12 months after operation (stage 4). The radiographs were digitized at 600 dpi, 8 bit, and 256 gray levels. The region of interest, centered on the bony gap area of the operation site, was selected and the fractal dimension was calculated by using the tile-counting method. The mean values and standard deviations of fractal dimension for each stage were calculated and the differences among stage 0, 1, 2, 3, and 4 were evaluated through repeated measures of the ANOVA and paired t-test. Results : The mean values and standard deviations of the fractal dimensions obtained from stage 0, 1, 2, 3, and 4 were 1.658±0.048, 1.580±0.050, 1.607±0.046, 1.624±0.049, and 1.641 ±0.061, respectively. The fractal dimensions from stage 1 to stage 4 were shown to have a tendency to increase (p < 0.05). Conclusion: The tendency of the fractal dimesion to increase relative to healing time may be a useful means of evaluating post-operative bony healing of the osteotomy site.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.239-244
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• 2004

In this paper, we have developed a frequency mixer which can be used as a microwave phase conjugator in the LS band retrodirective antenna system. The mixer as a phase conjugator must have an If signal of which frequency is nearly as high as that of an RF signal, so this fact brings difficulty in the combination of input signals and the design of impedance matching circuit. The circuit configuration is chosen to be of the gate mixer using a pseudomorphic HEMT device. The operating frequencies are 4.00 ㎓, 2.01 ㎓, and 1.99 ㎓ for LO, RF, and IF, respectively. Conversion gain is measured to be 12.5 ㏈ and 1 ㏈ compression point -34 ㏈m at the LO power of -7 ㏈m. The mixer fabricated in this research is the single-ended type, where RF leakage signal appears inevitably at the If port because RF and If frequencies are almost the same. The circuit topology suggested here can be applied directly to the design of balanced-type mixers and phase conjugators.