헬리코박터 파일로리 감염에 대한 맞춤형 치료의 최근 경향

Hyungchul Park,Jeong Hoon Lee 대한상부위장관ㆍ헬리코박터학회 2021 Korean Journal of Helicobacter Upper Gastrointesti Vol.21 No.2

The efficacy of the standard triple eradication regimen for Helicobacter pylori (H. pylori) infection is gradually decreasing due to increased antibiotic resistance of H. pylori, which is represented by clarithromycin resistance. This is an important issue for clinicians. Tailored therapies for H. pylori infection, including culture-based susceptibility testing and molecular methods detecting genetic mutations that increase resistance to antibiotics, have been introduced to overcome the high treatment failure rate of the standard triple regimen. The treatment results have been satisfactory. In addition to the H. pylori-related factors, the CYP2C19 gene polymorphism, in terms of host factors, affects the effectiveness of proton pump inhibitors. This article reviews the status of the tailored therapies for H. pylori infection along with the proven therapeutic effects and benefits of such treatments in Korea, where the resistance to antibiotics such as clarithromycin, metronidazole, and quinolone is prevalent.

Automated structural modal analysis method using long short-term memory network

Hyungchul Yoon,Jaehyung Park,Jongwon Jung,Seunghee Park 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.31 No.1

Vibration-based structural health monitoring is used to ensure the safety of structures by installing sensors in structures. The peak picking method, one of the applications of vibration-based structural health monitoring, is a method that analyze the dynamic characteristics of a structure using the peaks of the frequency response function. However, the results may vary depending on the person predicting the peak point; further, the method does not predict the exact peak point in the presence of noise. To overcome the limitations of the existing peak picking methods, this study proposes a new method to automate the modal analysis process by utilizing long short-term memory, a type of recurrent neural network. The method proposed in this study uses the time series data of the frequency response function directly as the input of the LSTM network. In addition, the proposed method improved the accuracy by using the phase as well as amplitude information of the frequency response function. Simulation experiments and lab-scale model experiments are performed to verify the performance of the LSTM network developed in this study. The result reported a modal assurance criterion of 0.8107, and it is expected that the dynamic characteristics of a civil structure can be predicted with high accuracy using data without experts.

Sarcopenia is associated with severe erectile dysfunction in older adults: a population-based cohort study

Hyungchul Park,Il-Young Jang,Minkyu Han,Heayon Lee,정희원,Eunju Lee,Dae Hyun Kim 대한내과학회 2020 The Korean Journal of Internal Medicine Vol.35 No.5

Background/Aims: Sarcopenia and erectile dysfunction (ED) are associated with poor health and quality of life in older men. We investigate the association between sarcopenia and severe ED in community-dwelling older men. Methods: We prospectively assessed sarcopenia and ED in 519, community-dwelling, older men (mean age, 74.0) in Pyeongchang, Korea, in 2016 to 2017. Sarcopenia was based on muscle mass, grip strength, and gait speed according to the Asian Working Group consensus algorithm. Severe ED was defined as 5-item International Index of Erectile Function questionnaire score under 8. Logistic regressions were used to study associations between incident severe ED and sarcopenia, after adjusting age, cardiovascular risk factors, depression, and polypharmacy. Results: The prevalence of severe ED was 52.4% and that of sarcopenia was 31.6%. At baseline, the prevalence of severe ED was higher in men with sarcopenia than in those without (73.2% vs. 42.8%; adjusted odds ratio [aOR], 1.89; 95% confidence interval [CI], 1.18 to 3.03; p = 0.008). Slow gait speed (aOR, 2.80; 95% CI, 1.18 to 6.62; p = 0.019) and decreased muscle mass (aOR, 2.54; 95% CI, 1.11 to 5.81; p = 0.027) were associated with the incidence of severe ED, while decreased grip strength (aOR, 0.76; 95% CI, 0.30 to 1.91; p = 0.564) was not. Conclusions: Sarcopenia was associated with severe ED. Slow gait speed, and decreased muscle mass was independently associated with incident severe ED at 1 year. Further research is warranted to examine whether an intervention targeting these components can prevent severe ED.

Analysis and design of compact third-order intermodulation generation circuits

Park, Hyun-Chul,Jung, Sung-Chan,Lim, Kyung-Hoon,Kim, Min-Su,Kim, Hyungchul,Park, Cheon-Seok,Yang, Youngoo Wiley Subscription Services, Inc., A Wiley Company 2009 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.51 No.9

<P>In this article, we analyzed and designed miniaturized third-order intermodulation distortion (IM3) generation circuits. An antiparallel Schottky diode pair was adopted for nonlinearity generation. A reflective configuration using a 90° hybrid coupler was employed to acquire a pure IM3 signal at the output. The fundamental signal at the output was automatically suppressed below the IM3 level using a reflective load optimized for the fundamental impedance of the antiparallel diode pair. The IM3 generation characteristics were fully analyzed using the Volterra series under a weak nonlinear assumption. A new optimum matching condition of the reflective load for the perfect fundamental cancellation was derived. A miniaturized 12 × 14 mm<SUP>2</SUP> IM3 generator was designed and implemented for the 2.16 GHz band, based on the analysis results. The output performance measured for the implemented IM3 generator matched the calculated results. The IM3 generator showed excellent fundamental cancellation characteristics and had a wide operational range for the input signal level. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2137–2140, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24535</P>

반능동형 머플러의 배압분포 특성에 관한 연구

노형철(Hyungchul Noh),박경석(Kyoungsuk Park),박세종(Sejong Park),변영호(Youngho Byun),한창평(Changpyung Han),손성만(Sungman Son) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_1

In design of muffler, Noise reduction is most important point in the past. By reason of this factor, study of muffler mainly used acoustic analysis for predictive modeling. but, recently muffler design factor, back pressure reduction and enhanced engine performance is more important than noise reduction. and developing process uses FEM and fluid analysis. but these process is not clearly defined the value for effective pressure.<br/> In this study, make experiment in muffler and semi-active muffler and analysis back pressure. This has made it possible to optimize muffler design, and defined design variable.

고장 주입 시뮬레이션 기반 자율주행 자동차의 안정성 분석 및 고장안전 사양 도출

박형철(Hyungchul Park),신민우(Minu Shin),권철현(Cheolhyeon Kwon) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6

본연구는 고장 주입 시뮬레이션을 통해 자율주행 차량의 고장에 대한 잠재적 위험성을 분석하고, 이를 통해 고장 발생시 자율주행차량이 대응할 수 있는 안전 메커니즘을 도출하고자 하였다. 포괄적이면서도 철저한 고장 주입 시뮬레이션 수행을 위해, i)MATLAB Simulink 기반의 14 자유도 차량 동역학 모델 및 오픈소스 기반의 자율주행 알고리즘을 구현하고; ii)미국 도로교통안전국 문서를 기반으로 차량 핵심 부품 별 고장 유형 및 도로 주행 시나리오를 세분화하였다. 또한, 차량 거동의 위험성 평가를 위해 Responsibility-Sensitive Safety (RSS) 개념을 적용하여 주입한 고장과 주행 시나리오 조합에 대한 정량적인 분석을 수행하였다. 분석 결과를 바탕으로 기존 자율주행 알고리즘에 추가적인 고장 대응안전사양을 추가적으로 적용하였고, 시뮬레이션을 통해 그 유효성을 확인하였다. This paper employs the software-in-the-loop fault injection test (FIT) methodology to develop the fail-safe mechanism of an autonomous driving car against various fault scenarios. To perform the comprehensive and exhaustive FIT, we implement: i) MATLAB Simulink-based 14DOF vehicle dynamics model and open-source based autonomous driving algorithms; and ii) diverse fault types with different driving scenarios according to the National Highway Traffic Safety Administration documents. Besides, the responsibility-sensitive safety concept is adopted to quantify the threat of individual faulty scenarios. Based on the FIT results, we further implement the corresponding fail-safe requirements into the autonomous driving algorithm, whose effectiveness is validated through the simulation.

직관 양상논리 IS5를 위한 양방향 증명탐색 방법

박형철(Hyungchul Park),박성우(Sungwoo Park) 한국정보과학회 2013 한국정보과학회 학술발표논문집 Vol.2013 No.11

나노 기술을 이용한 철도시스템의 성능 향상 방안

박철민(Chulmin Park),박영(Young Park),정호성(Hosung Jung),박현준(Hyunjune Park),김형철(Hyungchul Kim) 대한전기학회 2011 대한전기학회 학술대회 논문집 Vol.2011 No.7

TV 유휴대역 응용을 위한 무선 영상전송 시스템

박형열(Hyeongyeol Park),고인창(Inchang Ko),박형철(Hyungchul Park),신현철(Hyunchol Shin) 한국전자파학회 2015 한국전자파학회논문지 Vol.26 No.4

본 논문에서는 TV 유휴대역에서 가능한 응용서비스중 하나로서, UHF 대역(470∼806 ㎒)에서 동작하는 무선 영상전송 시스템을 구현하였다. 이 시스템은 RF 송수신기 모듈, 디지털 모뎀, 카메라, 스크린으로 구성된다. RF 송수신기와 디지털 모뎀을 연동하여 VGA급 화질의 카메라 영상을 2.6 인치 LCD 스크린에 표시하는 방식이다. RF 송수신기 구조는 크기와 비용을 줄이기 위해 직접변환 방식을 채택하였다. 성능지표인 Image Leakage를 향상시키기 위하여 PLL의 출력에 3차 하모닉 제거필터를 사용하였으며, DC offset 문제 해결을 위해 DAC 출력노드에 Current steering technique을 이용하여 공통모드 전압을 조절하게 하였다. 또한, 채널대역폭은 국가별 표준을 맞게 6, 7, 8 ㎒ 중 선택이 가능하다. 출력 파워와 수신감도는 각각 +10 ㏈m, ?82 ㏈m이다. 디지털모뎀은 Kintex-7급 FPGA에서 구현하였다. QPSK와 512ch OFDM 변조를 기반으로 전송속도는 약 9 Mbps이다. 개발된 송수신 모듈을 이용하여 VGA급 화질을 무선으로 송수신하는데 성공하였다. In this paper, a wireless video streaming system is designed and implemented for TV white space applications. It consists of a RF transceiver module, a digital modem, a camera, and a LCD screen. A VGA resolution video is captured by a camera, modulated by modem, and transmitted by RF transceiver module, and finally displayed at a destination 2.6-inch LCD screen. The RF transceiver is based on direct-conversion architecture. Image leakage is improved by low pass filtering LO, which successfully covers the TVWS. Also, DC offset problem is solved by current steering techniques which control common mode level at DAC output node. The output power of the transmitter and the minimum sensitivity of the receiver is +10 ㏈m and ?82 ㏈m, respectively. The channel bandwidth is tunable among 6, 7 and 8 ㎒ according to regulations and standards. Digital modem is realized in Kintex-7 FPGA. Data rate is 9 Mbps based on QPSK and 512ch OFDM. A VGA video is successfully streamed through the air by using the developed TV white-space RF communication module.

전기철도 집전시스템 성능평가 기술 분석

박영(Young Park),조용현(Cho Hyeon Young),김형철(Hyungchul Kim),이기원(Kiwon Lee),박찬배(Chanbae Park),김인철(In-Chol Kim) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

In response to increasing interest in speed up of overhead catenary systems, various measurement systems have been developed to evaluate interaction between a contact wire and a contact strip. Contact force, electric arc, and dynamic stagger between overhead contact wire and contact strip are examples of several existing methods for assessment of current collection performance. Additionally, dynamic uplift and strain of contact wire have to be considered, when a pantograph moves at a registration arm. This paper introduces criteria on stability and performance assessment related with speed enhancement for current collection system in electric railway. Tolerance values and measurement techniques of measured items such as contact wire dynamic, contact force, and contact wire uplift were widely mentioned.