적응적 루프필터의 지터 평균값을 이용한 ATSC DTV 심볼 타이밍 동기 방식

김주경,이주형,송현근,김재명,김승원,Kim, Joo-Kyoung,Lee, Joo-hyoung,Song, Hyun-keun,Kim, Jae-Moung,Kim, Seung-Won 대한전자공학회 2005 電子工學會論文誌-TC (Telecommunications) Vol.42 No.10

본 논문에서는 ATSC 지상파 DTV 시스템에서 심볼 타이밍 동기 성능 개선을 위한 알고리즘을 제안한다. 일반적으로 심볼 타이밍 동기를 위해 사용되는 가드너 방법은 다중 경로 페이딩 환경에서 성능이 좋지만 지터에 의해 성능 열화가 발생한다. 지터량는 루프 필터 대역폭이 작을수록 작아지지만, 수렴속도는 느려지게 된다. 본 논문에서는 수렴속도는 빠르면서 수렴 후 지터량를 감소시키기 위해 일정시간마다 루프필터의 출력 값을 평균하고 이 평균값을 이용하여 옵셋량을 추정한 후 점차적으로 대역폭을 줄여 지터의 크기를 줄이는 알고리즘을 제안한다. 제안하는 알고리즘은 기존의 방식에 비해 수렴속도와 지터의 기에서 좋은 성능을 보인다. This Paper Proposes the algorithm for improving the Performance or symbol timing synchronization in hoc terrestrial DTV system. The Gardner algerian is used for symbol timing synchronization has good performance in multipath fading environment but degradation of performance is caused by jitter. Though the amount of jitter becomes more little as narrow bandwidth of loop Inter, convergence speed becomes slower. This paper propose the algorithm that averages out values of loop filter every certain time and gradually reduces the bandwidth of loop filter after estimating offset using this average for the high speed of convergence and reducing the met of jitter. The proposed algorithm has better performance with high speed of convergence and the amount of jitter than conventional method.

높은 굽이 균형 수행과 근활성도에 미치는 영향

김주경,김민정,이성란,오태영,Kim, J.K.,Kim, M.J.,Kim, S.R.,Oh, T.Y. 대한물리치료과학회 2012 대한물리치료과학회지 Vol.19 No.1

Objectives : The purpose of this study was to determine the effects of high heeled shoes on the static & dynamic balance performance and electromyography(EMG) of back and lower extremity muscles. Materials & Methods : Sixteen women participated in this study. Subjects were composed two groups with LL shoes group and higher heel shoes group. We carried out Romberg's test and muscle activity of left and right Paraspinalis, Quadriceps femoris, Tibialis anterior, Gastrocnemius muscles by EMG in order to determine static balance performance according heel height. Using by Biorescue(Incenierie company), we trained subject to transfer of COG each direction(Anterior, posterior, Right, Left), we carried out this test for distance, surface, distance/surface in order to determine dynamic balance performance according heel height. The data were analyzed by independent t-test between lower and high heel height using SPSS(ver. 17.0)/PC program. Results : There was significant difference of distance(p<.05) of weight perturbation between lower and high group in dynamic balance performance and EMG value of left Gastrocnemius(p<.05), both Tibialis anterior(p<.05) muscle in static balance performance. Conclusions : Height of heel has effect on dynamic balance performance in distance of the Anterior, posterior direction. EMG of Gastrocnemius and Tibialis anterior muscles were affected by Romberg's test.

SSD 기반 스토리지 시스템에서 중복률과 입출력 성능 향상을 위한 데이터 중복제거 및 재활용 기법

김주경,이승규,김덕환,Kim, Ju-Kyeong,Lee, Seung-Kyu,Kim, Deok-Hwan 대한전자공학회 2012 전자공학회논문지 Vol.50 No.8

SSD(Solid State Disk)는 다수의 NAND 플래시 메모리로 구성되었으며 내부에 고성능 컨트롤러와 캐시 버퍼를 포함한 스토리지 장치이다. NAND 플래시 메모리는 제자리 덮어쓰기가 안되기 때문에 파일시스템에서 유효페이지가 갱신 및 삭제시 무효페이지로 전환되어 완전히 삭제하기 위해서는 가비지 컬렉션 과정을 거쳐야한다. 하지만 가비지 컬렉션은 지연시간이 긴 Erase 연산을 포함하기 때문에 SSD의 I/O 성능을 감소시키고 마모도를 증가시키는 문제가 된다. 본 논문에서는 입력데이터에 대하여 유효데이터와 무효데이터에서 중복검사를 실행하는 기법을 제안한다. 먼저 유효데이터에 대한 중복제거 과정을 거치고 그 다음에 무효데이터 재활용 과정을 거침으로써 중복률을 향상시켰다. 이를 통하여 SSD의 쓰기 횟수와 가비지 컬렉션 횟수를 감소시켜 마모도와 I/O 성능이 개선되었다. 실험결과 제안한 기법은 유효데이터 중복제거와 무효데이터 재활용을 둘다 하지 않는 일반적인 경우에 비해서 가비지 컬렉션 횟수가 최대 20% 감소하고 I/O 지연시간이 9% 감소하였다. SSD is a storage device of having high-performance controller and cache buffer and consists of many NAND flash memories. Because NAND flash memory does not support in-place update, valid pages are invalidated when update and erase operations are issued in file system and then invalid pages are completely deleted via garbage collection. However, garbage collection performs many erase operations of long latency and then it reduces I/O performance and increases wear leveling in SSD. In this paper, we propose a new method of de-duplicating valid data and recycling invalid data. The method de-duplicates valid data and then recycles invalid data so that it improves de-duplication ratio. Due to reducing number of writes and garbage collection, the method could increase I/O performance and decrease wear leveling in SSD. Experimental result shows that it can reduce maximum 20% number of garbage collections and 9% I/O latency than those of general case.

삼차 스플라인 보간법을 활용한 탈퇴율 전환방법

김주경,이항석,Kim, Ju Kyung,Lee, Hangsuck 한국통계학회 2013 응용통계연구 Vol.26 No.3

보험상품의 보험료를 계산하거나 리스크 관리를 하는 과정에서 다중탈퇴율이 필요하지만 경험 자료의 부족으로 절대탈퇴율을 다중탈퇴율로 전환하여 많이 사용한다. 다중탈퇴율과 절대탈퇴율간의 전환에는 소수연령분포를 균등분포로 가정하거나 탈퇴력을 상수로 가정하여 전환하는 방법을 주로 사용한다. 하지만, 이러한 가정하에서는 전환 시 오차가 발생하므로 본 연구에서는 전환오차를 줄이기 위하여 소수연령분포를 삼차 스플라인 함수로 추정하여 전환하는 방법을 제안한다. 기존에 많이 사용하던 방법은 탈퇴력이 불연속적이라는 특징이 있었으나 새로이 제시하는 방법은 탈퇴력이 연속적이라는 측면에서 차이가 있다. 수치 예를 통하여 기존의 방법과 오차를 비교해 봄으로써 스플라인 추정법이 오차를 줄이는데 효과적임을 확인할 수 있다. This paper discusses conversion methods between multiple decrement models and associated single decrement models. One of most popular assumptions on fractional age is UDD(uniform distribution of decrement) or constant force of mortality in actuarial practice. Instead of these assumptions, this paper suggests cubic spline interpolation to approximate the distribution of fractional age with the continuous force of decrements. Conversion formulas are derived. The comparisons of these two methods based on the numerical data show that the cubic spline interpolation approach is more accurate.

Current Situation of Home Oxygen Therapy for Chronic Obstructive Pulmonary Disease Patients in Korea

김주경,장승훈,Sung Hoon Park,Joo-Hee Kim,박지영,유광하,김영삼,임성용,황용일 대한의학회 2020 Journal of Korean medical science Vol.35 No.4

Background: Long-term oxygen therapy provides various benefits, including prolonged survival for severely hypoxic chronic obstructive pulmonary disease (COPD) patients. However, adequate management strategies for home oxygen therapy are not well established in Korea. This study aimed to explore the current situation of home oxygen therapy to provide basic data for developing a strategy for COPD patients on home oxygen therapy. Methods: In this cross-sectional study, we enrolled COPD patients using home oxygen therapy for at least 1 month. Face-to-face interviews were conducted, guided by a structured questionnaire about home oxygen therapy. Results: A total of 195 patients were enrolled. The mean age was 72.6 ± 9.7 years, and 76.4% of patients were men. The mean modified Medical Research Council, COPD Assessment Test, and EuroQol-5D index scores were 3.4 ± 0.8, 29.7 ± 6.8, and 0.35 ± 0.44, respectively. At rest, patients were prescribed oxygen for 12.5 ± 7.3 hr/day and used 12.9 ± 8.5 hr/day on average. During exercise, the mean duration of prescribed oxygen was 6.6 ± 4.3 hr/day, and the actual use was 1.1 ± 2.9 hr/day. A total of 25.6% of patients used ambulatory oxygen; with financial burden the main reason for nonuse. The mean number of hospitalizations and emergency room visits were 2.5 and 2.6, respectively. Conclusion: This study revealed low adherence to home oxygen therapy, poor health-related quality of life, frequent hospitalizations, and a high financial burden among COPD patients using home oxygen therapy. The study highlights the need for adequate strategies to improve the quality of home oxygen therapy.

머신 비젼을 이용한 2축 스테이지의 마이크로 원형 궤적 실시간 측정 및 분석

김주경,박종진,이응석,Kim, Ju-Kyung,Park, Jong-Jin,Lee, Eung-Suk 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.10

To verify the 2D or 3D positioning accuracy of a multi-axes stage is not easy, particularly, in the case the moving path of the stage is not linear. This paper is a study on a measuring method for the curved path accurately. A machine vision technique is used to trace the moving path of two-axes stage. To improve the accuracy of machine vision, a zoom lens is used for the 2D micro moving path. The accuracy of this method depends of the CCD resolution and array align accuracy with the zoom lens system. Also, a further study for software algorithm is required to increase the tracing speed. This technique will be useful to trace a small object in the 2D micro path in real-time accurately.

참여가 송전선로 수용성에 미치는 영향

김주경(Ju Kyong Kim),김지수(Gwang Gu Kim),김광구(Ji Soo Kim) 한국정책분석평가학회 2018 政策分析評價學會報 Vol.28 No.1

착농약송환법 적용을 위한 살충 화합물의 말벌류 방제 효율 평가

김주경(Ju-gyeong Kim),최용수(Yong-Soo Choi),강은진(Eun-Jin Kang),김수배(Su-bae Kim),김경문(Kyungmun Kim),박보선(Bo-sun Park),김동원(Dongwon Kim) 한국양봉학회 2021 韓國養蜂學會誌 Vol.36 No.3

The Asian hornet, Vespa velutina nigrithorax is one of the biggest enemies of honey bee in Korea. Beekeeping industry in Korea is being heavily affected due to its attack on honey bee populations. It is evident that colony targeted control efficacy is far effective than individual one. In this study, we tested the ingestion and contact toxicity of 24,000 ppm and 16,000 ppm clothianidin on adult V. analis . In addition, we also evaluated toxicity of the 16,000 ppm clothianidin in hornet colony and its nests. The hornet ingestion of 24,000 ppm and 16,000 ppm clothianidin had a mortality rate of 0% at 60 min, 63% at 120 min, and 100% at 150 min. When the hornet contacted with both concentrations of clothianidin, mortality rate was achieved above 60% at 30 min, and close to 100% at 60 min. However, when 16,000 ppm clothianidin was applied on the back of 10 hornets, they were found to return into their nests. Overall, the mortality rate of 75% and 100% was detected after 24 h and 48 h application, respectively. Clothianidin residual was detected at 3.43 ppm per a dead hornet. Therefore, it is possible to use the pesticide repatriation method with 16,000 ppm clothianidin to kill the hornet colony.

2021~2022년 국내 아까시나무 개화기 중의 꿀벌 질병 발생 현황

김주경(Ju-gyeong Kim),김경문(Kyungmun Kim),오대근(Daegeun Oh),최용수(Yong-Soo Choi),김동원(Dongwon Kim),김수배(Su-bae Kim),박보선(Bo-sun Park),강은진(Eun-Jin Kang) 한국양봉학회 2022 韓國養蜂學會誌 Vol.37 No.3

Several diseases of the honeybee (Apis mellifera L.) pose severe problems on honeybee production and productivity. In addition, it become a serious economic lost in the beekeeping sector. The acacia (Robinia pseudoacacia) honey is a major product of the beekeeping industry in Korea. Therefore, detecting diseases of honeybee is important during the blooming season of acacia. In this study, we performed the polymerase chain reaction (PCR) analysis to detect seven viruses (Sacbrood Virus (SBV); Acute Bee Paralysis Virus (ABPV); Deformed Wing Virus (DWV); Black Queen Cell Virus (BQCV); Kashmir Bee Virus (KBV); Chronic Bee Paralysis Virus (CBPV); Israel Acute Paralysis Virus (IAPV)), two bacteria (Paenibacillus larvae and Melissococcus pluton), and three fungi ( Ascosphaera apis, Nosema ceranae, and N. apis) in samples of honeybees ( A. mellifera) that were collected from 24 apiaries in Korea during the blooming season of acacia. In 2021, three diseases (BQCV, N. ceranae, and N. apis) were detected from 24, 23, and 24 apiaries respectively, and in 2022, seven diseases (SBV, DWV, BQCV, IAPV, EFB, N. ceranae, and N. apis) were detected from 4, 5, 24, 4, 1, 20, and 20 apiaries respectively. In particular, three viral diseases (SBV, DWV, and IAPV) were newly detected in 2022 from 4, 5, and 4 apiaries respectively. These diseases are mainly transmitted by Varroa destructor. This could be attributed to high damages caused by the V. destructor in 2022. Our present study could be a milestone to beekeepers in fighting against these diseases during the blooming seasons of acacia to bust up honey production and other hives products.

덩굴잡초(칡)에 대한 제초활성 검토

김덕환(Kim Duk-Hwan),김경현(Kim Kyung-Hyun),이계환(Lee Kye-Hwan),김정태(Kim Jung-Tae),신호철(Shin Ho-Cheol),김주경(Kim Joo-kyung) 한국잡초학회 2016 한국잡초학회 별책(학술대회 초록집) Vol.36 No.2