• Journal of Space Technology and Applications
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• v.1 no.3
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• pp.337-355
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• 2021

This paper is made to suggest a future strategy for the Korean High Resolution Wide Swath Synthetic Aperture Radar (HRWS SAR) satellite development by surveying the current trends for the SAR satellite technologies. From the survey, the latest SAR technology trends are revealed of using Digital Beam-Forming (DBF), SCan-On-Receive (SCORE), Displaced Phase Center Antenna (DPCA), interferometry, and polarimetry for exploiting the SAR imagery. Based on the latest SAR technology trends and the foreign HRWS SAR development cases, the strategy for the future HRWS Korean SAR satellite development is suggested to develop the DPCA and SCORE technologies by using the KOrea Multi-Purpose SATellite-6 (KOMPSAT-6) which is going to launch in a few years, and consequently to develop the HRWS SAR satellites which can monitor the whole Earth at weekly intervals.

• Journal of Korean Academy of Nursing
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• v.51 no.6
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• pp.720-731
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• 2021

Purpose: The purpose of this study was to identify the knowledge structure of health information (HI) for chronic obstructive pulmonary disease (COPD). Methods: Keywords or meaningful morphemes from HI presented on five health-related websites (HRWs) of one national HI institute and four hospitals, as well as HI needs among patients presented in nine literature, were reviewed, refined, and analyzed using text network analysis and their co-occurrence matrix was generated. Two networks of 61 and 35 keywords, respectively, were analyzed for degree, closeness, and betweenness centrality, as well as betweenness community analysis. Results: The most common keywords pertaining to HI on HRWs were lung, inhaler, smoking, dyspnea, and infection, focusing COPD treatment. In contrast, HI needs among patients were lung, medication, support, symptom, and smoking cessation, expanding to disease management. Two common sub-topic groups in HI on HRWs were COPD overview and medication administration, whereas three common sub-topic groups in HI needs among patients in the literature were COPD overview, self-management, and emotional management. Conclusion: The knowledge structure of HI on HRWs is medically oriented, while patients need supportive information. Thus, the support system for self-management and emotional management on HRWs must be informed according to the structure of patients' needs for HI. Healthcare providers should consider presenting COPD patient-centered information on HRWs.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04b
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• pp.126-132
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• 1996

A laboratory scale hot strip rolling wear simulator(HRWS) was developed for the purpose of investigating the tribological phenomena occurred in production hot strip rolling mills. The HRWS' main parts are the electric heater, the mechanical descaler, tandem type 2-4Hi rolling mill stands, the cooling chamber, the tension controller and coiler. By simulating the tribelogical phenomena in rolling process at laboratory, wear patterns, cracks, cat-ear wear, black film, effect of hot rolling oil lubrication, etc. were reproduced, and discussed on the performace of simulator.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.5
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• pp.31-36
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• 2024

In this paper, we designed and manufactured an ultra-wide band X-band SAR transceiver to implement HRWS. The manufactured transceiver is designed to operate at a bandwidth of 1500MHz, which results in a distance resolution performance of approximately 26cm at 67degrees incidence angle. To improve IRF performance, which is a performance indicator of wideband SAR signals, pre-distortion was performed for nonlinear distortion. Through predistortion, the PSLR value could be improved -13.13dB and -9.47 ISLR. To verify the de-chirp performance, a wide chirp signal was applied to the receiver's input and local signal. As a results, the -13.5dB PSLR value was confirmed through direct mixing of the chirp signal at the receiver. Through the developed ultra-wideband SAR transceiver technology, it is possible to achieve distance resolution of several tens of centimeters, and it is confirmed that not only direct receiving of wideband chirp signal but also de-chirp signal receiving by mixing wide chirp signal.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.353-363
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• 2020

Objectives: Occupational diseases that occur due to or aggravated by work have commonly been recognized in the manufacturing industry, but there are now more incidences happening in the service industry due to changes in the industrial structure. Health workers are exposed to direct factors and various other causes of occupational disease at work, such as physical, chemical, biological, and psyco-social factors. This study aims to identify work-related diseases affecting health workers that are recognized as occupational diseases. Methods: The research is based on the data of workers whose diseases were accepted as work-related by the Industrial Accidents Compensation Insurance, and filed by the Korean Occupational Safety and Health Agency. Amongst the approved claims during 2011 to 2015, we focused on healthcare workers and health-related workers of the Korean Standard Classification of Occupations. Descriptive statistics were performed. Results: The number of health workers(HWs) with approved work-related disease was 1,707 over 5 years. The number of healthcare workers(HCWs) excluding caregivers was 370 (21.7%) and of health-related workers (HRWs) it was 736 (43.1%). Out of HWs who were approved for their illnesses, females were 80% of HCWs and 88% of HRWs. The most common occupational disease in HWs was musculoskeletal diseases, while that of nurses was infectious disease. Conclusions: HWs are exposed to various risks from their profession and are affected by occupational diseases. It is necessary to focus on this issue and provide preventive measures.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.131-141
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• 2014

Synthetic Aperture Radar (SAR) is a powerful and well established microwave remote sensing technique which enables high resolution measurements of the Earth surface independent of weather conditions and sunlight illumination. In this study, this paper first summarizes the basic SAR theory and the history of the SAR satellites. The second part of this paper gives an overview of new technologies for future SAR systems. New innovative concepts and technologies for SAR satellites will be digital beamforming, High Resolution Wide Swath (HRWS), Waveform Encoding, Terrain Observation by Progressive Scan (TOPS), and so on. These technologies will play an important role for future spaceborne SAR satellites.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.464-472
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• 2018

Future spaceborne satellite synthetic aperture radar(SAR) system is expected to acquire high-resolution images over wide swath areas. Conventional SAR systems suffer from ambiguity problems in both azimuth and range directions that lead to image quality degradation. Recently, multiple input multiple output(MIMO) SAR techniques having multiple orthogonal waveforms are proposed to overcome the conventional ambiguity problems in wide-swath imaging modes. In this paper, noisy orthogonal frequency division multiplex(OFDM) waveforms are developed to reduce the ambiguity problems and suppress the image quality degradation. SAR simulations are performed to evaluate the performance of the proposed technique for wide-swath SAR imaging.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.3
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• pp.186-194
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• 2017

In this paper, we analyze the main performance of satellite's Synthetic Aperture Radar system for high resolution and wide swath. We have used the radiation pattern of reflector antenna with array feed and comparison between the conventional ScanSAR mode and SweepSAR mode has been carried out. The SweepSAR mode is a high-resolution wide-swath mode that transmits beams over a wide range and receives echo signals through sequential beamforming based on SCORE(SCan On REceive). In this paper, we analyzed the operating principle and characteristics of satellite's SweepSAR mode and simulate system performances. In addition, in order to increase the utilization of image, performances analysis for multiple frequency bands(C-band, X-band) has been considered.