• Journal of Trauma and Injury
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• v.36 no.3
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• pp.172-179
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• 2023

Purpose: Out-of-hospital traumatic cardiac arrest (TCA) often has a poor prognosis despite rescue efforts. Although the incidence and mortality of out-of-hospital cardiac arrest have increased, bystander cardiopulmonary resuscitation (CPR) has decreased in some countries during the COVID-19 pandemic. In the prehospital setting, immediate treatment of cardiac arrest is required without knowing the patient's COVID-19 status. Because COVID-19 is usually transmitted through the respiratory tract, airway management can put medical personnel at risk for infection. This study explored whether on-scene treatments involving CPR for TCA patients changed during the COVID-19 pandemic in Korea. Methods: This retrospective study used data from emergency medical services (EMS) run sheets in Gangwon Province from January 2019 to December 2021. Patients whose initial problem was cardiac arrest and who received CPR were included. Data in 2019 were classified as pre-COVID-19 and all subsequent data (from 2020 and 2021) as post-COVID-19. Age, sex, possible cause of cardiac arrest, and treatments including airway maneuvers, oropharyngeal airway (OPA) or i-gel insertion, endotracheal intubation (ETI), bag-valve mask (BVM) ventilation, intravenous (IV) line establishment, neck collar application, and wound dressing with hemostasis were investigated. Results: During the study period, 2,007 patients received CPR, of whom 596 patients had TCA and 367 had disease-origin cardiac arrest (DCA). Among the patients with TCA, 192 (32.2%) were pre-COVID-19 and 404 (67.8%) were post-COVID-19. In the TCA group, prehospital treatments did not decrease. The average frequencies were 59.7% for airway maneuvers, 47.5% for OPA, 57.4% for BVM, and 51.3% for neck collar application. The rates of ETI, i-gel insertion, and IV-line establishment increased. The treatment rate for TCA was significantly higher than that for DCA. Conclusions: Prehospital treatments by EMS workers for patients with TCA did not decrease during the COVID-19 pandemic. Instead, the rates of ETI, i-gel insertion, and IV-line establishment increased.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1972-1975
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• 2002

In this paper, we have proposed low temperature co-fired ceramic (LTCC) based packaging for RF MEMS devices. The packaging structure is designed and evaluated with 3D full field simulation. 50 ${\Omega}$ matched coplanar waveguide(CPW) transmission line is employed as the test vehicle to evaluate the performances of the proposed package structure. The line is encapsulated with the LTCC packaging lid and connected to the via feed line. To reduce the insertion loss due to the packaging lid, the cavity with via post is formed in the packaging lid. The performances of the package structure is simulated with the different cavity depth and via-to-via length. Simulation results show that the proposed package structure has reflection loss better than 20 dB and insertion loss lower than 0.1 dB from DC to 30 GHz with the cavity depth and via-to-via length of 300 ${\mu}m$ and 350 ${\mu}m$, respectively. To realize the designed package structure, the cavity patterning is tested using the sandblast of LTCC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.67-71
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• 2008

We report the waveguide to microstrip transition using probe structure for Ka-band transceiver. The waveguide to microstrip transition is composed of probe, inductive line, ${\lambda}/4$ impedance transformer, and $50{\Omega}$ microstrip line. For design of the transition, we optimized the characteristic impedances and the lengths of the component parts. The fabricated transition exhibits an insertion loss of 1.3 dB and the input/output return losses of below 14 dB between 30 and 40 GHz. The insertion loss of each transition is about $0.5{\sim}0.6dB$, considering the losses in the microstrip line and input/output waveguides.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1376-1385
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• 2000

The phase characteristic of delay line in feedfarward linearizer has been changed due to variation of operating temperature. In this paper, design method of fixed phase control circuit of group delay line using adaptive vector control is derived. To maintain transfer characteristics of nominal operating temperature, the error correlated signals, which are changed adaptively due to changing of temperature, are added to main signals. The proposed method maintains transfer characteristics under 0.06dB of insertion loss and 0.36$^{\circ}$ of phase variation in case of 1-tone(880 MHz) and under 0.07 dB of insertion loss and 0.35$^{\circ}$ of phase variation in case of 2-tones(877 MHz, 882 MHz) for 10dB input power dynamic range and +/-10$^{\circ}$ phase variation respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.11
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• pp.831-837
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• 2003

This paper investigates the insertion loss of nosie barrier with a interference device, The efficiency of the conventional interference-type noise barrier depends on specific frequency, Thus this study is performed to improve the efficiency of the nosie barrierin the range of broadband frequency. by changing the shape of interference device and adding the channel with various depths, The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.749-754
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• 2002

This paper investigates the insertion loss of nosie barrier with a interference device. The efficiency of the conventional interference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the nosie barrier in the range of broadband frequency, by changing the shape of interference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• Journal of Chest Surgery
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• v.40 no.5 s.274
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• pp.388-391
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• 2007

Subclavian catheter insertion is now widely used because of its technical feasibility and effectiveness, but some complications related to this procedure have been noted. We present here a rare surgical case of post central line insertion mediastinitis with no mechanical complication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.73-76
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• 1997

A low loss x-cut LiNbO$_3$ optical waveguide was fabricated by Ti in-diffusion and the guided-mode properties and total insertion loss of pigtailing with polarization maintaining fiber(PMF) were investigated and measured at optical wavelength 15507. For formaing the waveguide, the parameters of diffusion Ti thickness, waveguide line-width, length, diffusion temperature, time and atmosphere were set 1400$\AA$, 8${\mu}{\textrm}{m}$, 3.3cm, 105$0^{\circ}C$, 8 hours and wet bubbled oxygen, respectively. and then After the polishing and pigtailing, it showed that total insertion loss was -4.1dB for TM mode, -5.5dB for TE mode, and mode size, that is, horizontal/vertical sizes were 13.87/18${\mu}{\textrm}{m}$ for TM mode, 9.61${\mu}{\textrm}{m}$/6.5${\mu}{\textrm}{m}$ for TE mode.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.8
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• pp.995-999
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• 2014

In this paper, a new size-reduction approach for branch-line coupler is introduced which uses parallel end-shorted coupled lines with lumped capacitors. The characteristic of the new design was analyzed using even-odd mode method, and simulated on HFSS before fabricated on the FR4 epoxy glass cloth copper-clad plat (CCL) PCB substrate at center frequency of 1 GHz. The electrical length of transmission line was reduced to 15 degrees, therefore the size of branch-line coupler was largely reduced approximately maintaining the same characteristic around the stable center frequency. The insertion loss of the branch-line coupler filter was -4.39 dB. The size of the overall hybrid is $20mm{\times}20mm$. Measurements results were well agreed with the simulated ones.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.63-70
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• 1985

In this paper, the Unilateral Fin-line structure and the I-Plane structure are analysed by Rayleigh-Ritz variational method including the effect of conductor thickness. And a com-putcr-aided design program, CADUNI, is developed for microwave I-plane and Unilateral Fin-Line bandpass filters. Unilateral Fin-Line Filters are desigied at the center frequency of 10.5 GHz with guided bandwidth between 5% and 24.6%. Measured insertion loss is between 0.17 and 0.25 dB, and center frequency deviation is less than 0.2%. Experimental results are in good agree-ment with theory.