다중필터링에 의한 PDC-R 기법의 자동화 해석

조성호(Joh Sung-Ho),노리나(Rahman Norinah Abd),하사눌(Hassanul Raja) 대한토목학회 2010 대한토목학회논문집 C Vol.30 No.3

지반내 존재하는 자연전위, 돌발성 전기잡음, 60㎐ 전기잡음 등은 전기비저항 시험에 있어서 신뢰성을 저하하는 요인 중의 하나이다. 특히 최근 개발된 저주파 교류를 사용하는 PDC-R(Pseudo DC Resistivity) 시험의 자료해석에 있어서도 해석의 신뢰성을 저하시키는 요인이 되고 있다. 즉 직류기반 전기비저항 시험, 교류기반 전기비저항 시험 모두에 있어서 정도의 차이가 있을 뿐 전기잡음은 전기비저항 기법의 신뢰도에 여전히 영향을 주고 있다. 본 연구에서는 PDC-R 기법의 자료해석에 있어서 전기잡음의 영향을 최소화하여 기법의 신뢰성을 제고할 수 있는 방안을 제시하였다. 또한 이를 구현하는 자동화 알고리듬을 이용하여 PDC-R 기법의 적용성도 개선하도록 하였다. 본 연구에서 제안하는 PDC-R 시험데이터의 자동화 해석 기법은 두 단계로 구성되어 있는데, 그 첫 번째는 다중필터링을 시용하여 입력전류와 동일한 주파수 성분을 추출하는 것이고, 두 번째 단계는 추출된 자료 중에서 안정적 거동의 신호성분만 분류해 내는 작업을 수행하는 것이다. 이러한 자동화 기법은 자연전위, 돌발성 잡음, 60㎐ 전기잡음 등을 포함한 가상의 조화함수를 이용하여 그 정확성과 안정성을 확인하였다. 또한 현장적용을 통하여 제안된 기법의 적용성 및 정확성도 확인할 수 있었다. Electrical noises like self potential, burst noises and 60-㎐ electrical noises are one of the causes to reduce reliability of electrical resistivity survey. Even the PDC-R (Pseudo DC resisitivity) technique, recently developed, is suffering from the problem of low reliability due to electrical noises. That is, both DC-based and AC-based resistivity technique is subject to reliability problem due to electrical noises embedded in urban geotechnical sites. In this research, a new technique to enhance reliability of the PDC-R technique by minimizing influence of electrical noises was proposed. In addition, an automated procedure was also proposed to facilitate data analysis and interpretation of PDC-R measurements. The proposed technique is composed of two steps: 1. to extract information only related with the input current by means of multiple-filter technique, and 2. to undertake a task to sort out signal information only to show stable and reliable characteristics. This automated procedure was verified by a synthetic harmonic wave including DC shift, burst random noises and 60-Hz electrical noises. Also the procedure was applied to site investigation at urban areas for proving its feasibility and accuracy.

초고온·고압 소결 공정으로 제조된 다결정 다이아몬드 컴팩트(PDC)의 VTL 마모 특성에 미치는 Co 제거의 영향

백민석,김지원,박배건,박희섭,이기안 대한금속·재료학회 2020 대한금속·재료학회지 Vol.58 No.7

Polycrystalline diamond compact (PDC) has excellent wear resistance, high impact resistance, superior fatigue properties, and has been used in the oil and gas drilling industries. This study investigated the effect of Co leaching on the microstructure, vertical turning lathe (VTL) wear properties of PDCs manufactured by high-temperature and high-pressure (HTHP) sintering. The VTL wear test has the advantage of simulating the actual oil drilling environment by using granite as the workpiece. PDC sintered material that did not receive Co leaching was named HTHP sintered PDC-A, and the material subjected to Co leaching was called Co-leached PDC-B in this study. As a result of XRD analysis of both PDCs, diamond and WC peaks were detected, and only the HTHP sintered PDC-A exhibited some Co peaks. In the HTHP sintered PDC-A, the binder WC and Co were evenly distributed at the diamond interface. However, in the Co-leached PDC-B, some empty spaces were observed at the diamond interface. The HTHP sintered PDCA exhibited a similar or slightly higher VTL wear resistance than the Co-leached PDC-B, but only in the short sliding distance. In the long sliding distance after 9 km, Co-leached PDC-B showed significantly superior wear resistance compared to the HTHP sintered PDC-A. The HTHP sintered PDC-A exhibited both abrasive and adhesive wear behaviors, while the Co-leached PDC-B showed only abrasive wear. Based on the above results, the VTL wear mechanism of PDCs, and ways of improving wear resistance were also discussed.

PDC와 적분 슬라이딩 모드 제어를 결합한 이동 로봇의 강인 궤도 추적 제어

박민수,박승규,안호균,곽군평,윤태성,Park, Min-soo,Park, Seung-kyu,Ahn, Ho-kyun,Kwak, Gun-pyong,Yoon, Tae-sung 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.7

In this paper, a robust trajectory tracking control method of a wheeled mobile robot is newly proposed combining the PDC and the ISMC. The PDC is a relatively simple and easy control method for nonlinear system compared to the other non-linear control methods. And the ISMC can have robust and stable control characteristics against model uncertainties and disturbances from the initial time by placing the states on the sliding plane with desired nominal dynamics. Therefore, the proposed PDC+ISMC trajectory tracking control method shows robust trajectory tracking performance in spite of external disturbance. The tracking performance of the proposed method is verified through simulations. Even though the disturbance increases, the proposed method keeps the performance of the PDC method when there is no disturbance. However, the PDC trajectory tracking control method has increasing tracking error unlike the proposed method when the disturbance increases. 본 논문에서는 병렬 분산 보상 (PDC) 제어와 적분 슬라이딩 모드 제어 (ISMC)를 결합하여 바퀴형 이동 로봇의 강인한 궤도 추적 제어 방법을 새롭게 제안한다. PDC 제어 방법은 다른 비선형 제어 방법에 비해 비교적 간단하고 사용이 편리하다. 그리고 ISMC는 상태 변수들을 원하는 공칭 동특성을 갖는 슬라이딩 평면에 배치함으로써 초기 순간부터 모델 불확실성 및 외란에 대해 강인하고 안정적인 제어 특성을 갖게 할 수 있다. 그러므로 제안된 PDC+ISMC 궤도 추적 제어 방법은 외란에도 불구하고 강인한 궤도 추적 제어 성능을 보여준다. 제안된 궤도 추적 방법에 대해 시뮬레이션을 통하여 외란이 있는 경우의 궤도 추적 성능을 확인하였다. 제안된 방법은 외란이 증가하더라도 외란이 없을 때의 PDC 제어 방법에 의한 궤도 추적 성능을 유지하였다. 그러나 PDC 궤도 추적 방법은 외란의 크기가 증가하면 제안된 방법과는 달리 궤도 추적 오차가 크게 증가함을 알 수 있었다.

Al-1%Si 박막 배선의 DC와 PDC 조건에서의 일렉트로마이그레이션 및 시뮬레이션

고형석,김진영 광운대학교 신기술연구소 1996 신기술연구소논문집 Vol.25 No.-

본 연구에서는 Al-1%Si 박막 배선의 DC와 PDC에서의 일렉트로마이그레이션 현상에 의한 결함발생을 관찰하였고, DC에 대한 PDC 조건의 수명 증가에 대한 해석을 위해 시뮬레이션을 실행하였다. 가속화 실험 결과 PDC에서 박막 배선의 수명이 DC 보다 10-20배 정도 길게 나타났으며, 박막배선의 길이가 증가할 수록 수명은 DC와 PDC 모두 감소하였다. 이로 부터 박막 배선의 길이가 증가할 수록 수명이 감소하는 것을 알 수 있다. 컴퓨터 시뮬레이션의 결과 PDC 조건에서의 박막 배선의 수명 증가의 원인으로써 박막 배선의 동작 온도가 인가된 전류밀도와 전류의 주파수에 대하여 DC 조건보다 낮기 때문에 박막 배선의 결함 발생이 억제되어 수명이 증가하는 것으로 사료된다. We studied the electromigration of Al-1%Si under DC and PDC, and run computer simulation to explain the lifetime increasement of PDC. Lifetime under PDC was longer than DC by 10∼20 times, and as thin film interconnection length increase, lifetime was decreased. Computer simulation explained that increasing of lifetime under PDC due to the heat dissipation at current off times. The temperature of thin film under PDC is lower than DC and depends on current density and frequency, therefore failure growth rate was lower than DC.

파라미터 불확실성을 갖는 이산시간 비선형 상호결합 시스템을 위한 강인 분산 제어기 설계

구근범(Geun Bum Koo) 한국지능시스템학회 2019 한국지능시스템학회논문지 Vol.29 No.3

본 논문에서는 이산시간 비선형 상호결합 시스템을 위한 강인 분산 퍼지 제어기 설계 기법을 제시한다. 이때, 상호결합 시스템은 불확실한 파라미터를 가질 뿐만 아니라, 미지의 상호결합성을 가진다고 가정한다. 비선형 상호결합 시스템의 퍼지 하위 시스템을 기반으로 분산 퍼지 제어기의 구조를 PDC기반과 Non-PDC 기반으로 모두 제안하며, 분산 퍼지 제어 설계 목적을 정의한다. Lyapunov 함수를 기반으로, 제어기를 포함한 폐루프 시스템의 안정도 조건을 구하고, 유도된 안정도 조건은 최대 상호결합 범위를 구할 수 있는 선형 행렬 부등식의 형태로 표현한다. 마지막으로 수치적 예제를 통해 PDC 기반과 Non-PDC 기반의 제어 성능 차이를 확인하고, 제시한 분산 퍼지 제어 기법의 효용성을 입증한다. In this paper, robust decentralized fuzzy controller design methods are presented for discrete-time nonlinear interconnected systems, which are assumed to have not only parametric uncertainties, but also unknown interconnections. Based on fuzzy subsystems of the nonlinear interconnected system, structures of decentralized fuzzy controllers are presented for both PDC and Non-PDC techniques. Also, the decentralized fuzzy controller design problem is defined. By using Lyapunov functional, each stability condition of closed-loop systems with decentralized controllers is guaranteed, and its condition is formulated into linear matrix inequalities with the maximum interconnection bound. Finally, by the numerical simulation, the performances are compared between PDC and Non-PDC control, and the validity of the proposed decentralized fuzzy controller design technique is shown.

Study on Influences and Elimination of Test Temperature on PDC Characteristic Spectroscopy of Oil-Paper Insulation System

Xiao Liu,Ruijin Liao,Yandong Lv,Jiefeng Liu,Jun Gao,Jian Hao 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

Study on Influences and Elimination of Test Temperature on PDC Characteristic Spectroscopy of Oil-Paper Insulation System

Liu, Xiao,Liao, Ruijin,Lv, Yandong,Liu, Jiefeng,Gao, Jun,Hao, Jian The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

Overexpression of ARO10 in pdc5ΔMutant Resulted in Higher Isobutanol Titers in Saccharomyces cerevisiae

Jingzhi Li,Ruiqi Feng,Zhihui Wen,Aili Zhang 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.4

To investigate effects of different pyruvate decarboxylases on isobutanol titers in Saccharomyces cerevisiae, single-gene deletion of the three PDCs genes encoding pyruvate decarboxylases were constructed in this study. In addition, we over-expressed Ilv2, which catalyzed the first step in the valine synthetic pathway, and Bat2, which was the cytoplasmic branched-chain amino-acid aminotransferase that catalyzed L-valine to 2-ketoisovalerate, to increase isobutanol production in the genetically modified strains. Our results showed that knockout of PDC5 were one of the main factors among the three PDC genes for improving isobutanol titers in S. cerevisiae. Additionally, we found that deletion of PDC5 in strain carrying overexpressed ILV2 and ARO10 resulted in 8-fold higher isobutanol productivity as compared to the control strain in micro-aerobic fermentations. Our results also suggested that engineered strain pdc5ΔpILV2 pARO10 generated lower ethanol titers and higher acetate acid titers than the control strain, while the growth rate and glucose consumption rate of engineered strain pdc5ΔpILV2 pARO10 were slightly lower than that of the control strain. Meanwhile, the biomass concentration of pdc5ΔpILV2 pARO10 decreased dramatically than that of the control strain.

Sequence Analysis and Functional Expression of the Structural and Regulatory Genes for Pyruvate Dehydrogenase Complex from Streptomyces seoulensis

HwanYoun,JangyulKwak,Dong-WonKim,Chang-JinLee,Yang-InYim,Jin-WonLee,In-KwonKim,Jeong-IlYu,임형순,Sa-OukKang 한국미생물학회 2002 The journal of microbiology Vol.40 No.1

A cluster of genes encoding the pyruvate dehydrogenase complex (PDC) of Streptomyces seoulensis, a Gram-positive bacterium, was cloned and sequenced. The genes of S. seoulensis consist of four open reading frames. The first gene, lpd, which encodes a lipoamide dehydrogenase, is followed by pdhB encoding a dihydrolipoamide acetyltransferase (E2p), pdhR, a regulatory gene, and pdhA encoding a pyruvate dehydrogenase component (E1p). E1p had an unusual homodimeric subunit, which has been known only in Gram-negative bacteria. S. seoulensis E2p contains two lipoyl domains like those of humans and Streptococcus faecalis. The pdhR gene appears to be clustered with the structural genes of S. seoulensis PDC. The PdhR-overexpressed S. seoulensis showed growth retardation and the decrease of E1p, indicating that PdhR regulates the function of PDC by repressing the expression of E1p. A strain of Streptomyces lividans overexpressing S. seoulensis PdhR showed a significant decrease in the level of actinorhodin, implying a regulatory role for Streptomyces PDC in antibiotic biosynthesis.

올-디지털 위상 고정 루프용 오프셋 및 데드존이 없고 해상도가 일정한 위상-디지털 변환기

최광천(Kwang-Chun Choi),김민형(Min-Hyeong Kim),최우영(Woo-Young Choi) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.2