• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.161-166
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• 2009

In this paper, we propose the internal mobile antenna for TDMB and KPCS. The proposed antenna is made of different dielectric substrate and it has small size ($45{\times}8{\times}8\;mm$, about 2.8 cc) for mobile device. TDMB antenna is designed spiral structure that makes maximum current for each cell and KPCS antenna is PIFA that is usually used for internal antenna. In order to compensate length of resonance TDMB antenna has a large inductor above 100 nH. In this case, the inductor isolate KPCS signal at TDMB by cutting high frequency. Also the antenna has good isolation because TDMB radiator is parasitic element in KPCS band. We simulated the antenna by using CST microwave studio and measured performance of the antenna in anechoic chamber Proposed antenna has $-6{\sim}-14\;dBi$ gain for TDMB and $-3.5{\sim}-5\;dBi$ gain for KPCS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1113-1119
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• 2013

In this letter, a new approach is proposed for the design of a multi antenna for MIMO wireless devices. The proposed antenna covers various LTE(Long Term Evolution) service bands: band 17(704~746 MHz), band 13(746~787 MHz), band 5(824~894 MHz), and band 8(880~960 MHz). The proposed main antenna consists of a conventional monopole antenna with an inverted L-shaped slit for wideband operation. The proposed the LTE sub antenna is based on a switch loaded loop antenna structure, with a resonance frequency that can be controlled by capacitance of a logic circuit. The tuning technique for the LTE Rx antenna uses a RF MEMS(Micro-Electro mechanical system) to match the impedances to realize the bands of interest. Because the two proposed antennas are polarized orthogonally to each other, the ECC(Envelope Correlation Coefficient) characteristic between two antennas was measured to be very low (below 0.06) with an isolation characteristic below -20 dB between the two antennas in the operating overall LTE bands. The proposed antenna is particularly attractive for mobile devices that integrate LTE multiple systems.

• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.47-51
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• 2013

In this paper, we present design and test results of a Ka-band dual-band ortho-mode transducer (OMT) for use in a feed assembly for the very small aperture terminals (VSATs). The designed ortho-mode transducer have wideband characteristics to separate the signals that have two orthogonal linear polarizations operating at 20GHz of receive frequency band and at 30GHz of transmit frequency band. In addition, in order to reduce the volume of the feed assebly, a Boifot based ortho-mode transducer has been designed with a dual-band. Experimental results for the design verification, the return loss in the receive band and in the transmit band for the horizontal polarization showed over 20dB and 21dB, respectively, and for the vertical polarization showed over 20dB and 24dB, respectively. The port isolation for the horizontal polarization and the vertical polarization showed over 43dB and 52dB, respectively, in the receive band and in the vertical band.

• The Journal of Engineering Geology
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• v.12 no.3
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• pp.319-332
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• 2002

This study is focused on the characterization of an effective hydraulic conductivity in each hydrogeologic unit assumed as an equivalent continuum medium in the granitic area. Four boreholes of 3" diameter were installed and a Multi-packer system was facilitated in the selected borehole. Various in-situ tests including the fracture logging, constant injection and fall-off tests, slug and pulse tests were carried out. A hydrogeologic unit was defined into the upper and lower zones based on the variation of fracture properties and hydraulic conductivities. The difference of the result obtained by the various hydraulic tests and the effective characterization techniques on rock mass permeability are also discussed. The effective hydraulic conductivity of the upper unit was measured by two times(5.27E-10 m/s~7.57E-10 m/s) that of the lower unit(2.45E-10 m/s~6.81E-10 m/s)through the constant injection and fall-off tests.

• Korean journal of applied entomology
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• v.41 no.1
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• pp.33-41
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• 2002

The mirid bug damages on grapevine were observed not only on young shoot and leaves (decoloration, deforming, and perforation) but also on fruits (black spot, corky scar, and young fruit shattering). Among 159 fields surveyed throughout the country, 113 fields (71%) were damaged, and the damages were relatively severer in the chief producing districts of grape vine, such as Gimpo, Anseong, Naju, Gimcheon, Buyeo, Daejeon, Yesan than other districts where grapevine yards were not concentrated. The severest shoot damages were observed in two grape vine yards of Naju (85%) and Gimpo (65%) in 1999. Three species of virid bugs were recognized on grape vine tree, Apoygus spinolae (Meyer-Dur), Apolygus lucorum (Meyer-Dur), and Orthotylus (Melanotrichus) flavosparsus(Sahlberg). Among them, A. spinolae was dominant species in the number of specimens collected. A. spinolae were collected on 10 host plants including Vitis vinifera L., Prunus armeniaca var. ansu Max., and prunus serrulata var. spontanea(Max.) Wils. and etc., and A. lucorum were collected on 10 species of plants, including Artemisia iwayomogi Kitamura, Artemisia princeps var. orientalis(Pampan) Hara and etc. Both A. spinolae and A. lucorum distributed widely in Korean grapevine yards.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.371-383
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• 2004

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks (SFN) in the Advanced Television Systems Committee (ATSC) transmission systems and propose equalization digital on-channel repeater (EDOCR) that overcomes the limitations of conventional digital on-channel repeaters (DOCRs). Since there are no forward error correction (FEC) decoder and encoder, the EDOCR does not have an ambiguity problem. In addition, since an adaptive equalizer in the EDOCR removes multi-path signals, additive white Gaussian noise (A WGN), and feedback signal due to low antenna isolation, the EDOCR may have good output signal quality with high power.

• Journal of Korean Academy of Nursing
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• v.51 no.5
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• pp.585-596
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• 2021

Purpose: The purpose of this study was to explore nurses' experience with caring for COVID-19 patients in a negative pressure room amid the spread of the pandemic. Methods: This study was a qualitative research, and focus group interviews were used to collect data. Three focus groups comprising 19 nurses were interviewed from February 17 to 25, 2021. All interviews were recorded and transcribed verbatim with the consent of the participants. The verbatim transcripts were scrutinized using thematic analysis. Results: Two main themes emerged from the analysis: 'Struggling in an isolated space' and 'Limitations of nursing infrastructure and system'. The nurses caring for COVID-19 patients experienced anxiety and fear about the infection, physical exhaustion, emotional burnout, and a sense of duty as a nurse. They also acknowledged the lack of guidelines, increased task and burden, limitations of nursing care, and the demand for improving the limitations of the nursing system. Conclusion: The results of this study demonstrate that nurses caring for COVID-19 patients encounter physical and emotional problems within the limited healthcare system. The study suggests that comprehensive interventions are needed for nurses. Furthermore, detailed guidelines, strengthening of nursing personnel, and improvements to the nursing system are vital to effectively cope with the pandemic. The government and medical institutions should be aware of the needs of nurses and what they are going through, and make efforts to improve the quality of life of healthcare workers and create a safe healthcare environment.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.6
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• pp.69-84
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• 2020

This study is conducted to improve the quality of healthcare services responding to COVID-19 by applying the public service quality management framework that is developed from ISO18091:2019 by the Ministry of the Interior and Safety of South Korea. The COVID-19 pandemic has been impacting the world since early 2020, and now in November 2020, it still has not been eliminated. The Korean medical institutions were able to prevent the spread of COVID-19 by agile test and strict cohort isolation. As a result, the so-called K-medical defense has achieved a positive reputation from around the world. In this study, we check and evaluate the current status of the COVID-19 response targeting some Korean hospitals by applying a quality control checklist based on the public service quality management framework. Status of 7 categories are analyzed based on the interview with 3 medical institutions. We also suggest improvements for better medical service quality in case of COVID-19 being prolonged.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.317-325
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• 2021

By analyzing the recognition analysis and motivation method of the determinants, this study investigates the future development direction of health exercise biodata analysis face-to-face practice education content. The participants were 40 millennial and zoomers (MZ) generation college graduates. Factors related to the decision to participate in face-to-face practice classes in the field of health exercise biodata and bio-digital content convergence technology in the era of COVID-19 were measured. Of the participants, 67.5% voluntarily decided to participate in small group classes while observing social distancing rules. This study presented the most effective and learning motive methods to participate in face-to-face training. Health exercise biodata needs improvement in terms of integrating with adjacent disciplines such as big data.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.349-358
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• 2022

This study was aim to understand the relationship between uncertainty, social isolation, social support and resilience of coronavirus infectious diseases-19 (COVID-19) patients and to identify factors related to resilience. Data were carried out from March 7 to May 5, 2021, and a total of 200 questionnaires were used for data analysis. Data were analyzed with descriptive statistics, t-test, ANOVA, Pearson correlation coefficient and multiple regression using SPSS WIN 24.0 program. As a result of the analysis, the lower the sense of social isolation, the higher the social support, the satisfaction with the explanation of isolation and the economic status of 'medium' were identified as related factors for resilience. Based on the above results, a systematic program should be developed and applied to improve the resilience of COVID-19 patients including strengthening social support through families and health care providers, reducing social isolation through non-face-to-face counseling, providing sufficient information about diseases, and providing economic support.