• 제목/요약/키워드: false current

검색결과 157건 처리시간 0.049초

Transformer Differential Relay by Using Neural-Fuzzy System

  • Kim, Byung Whan;Masatoshi, Nakamura
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.157.2-157
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    • 2001
  • This paper describes the synergism of Artificial Neural Network and Fuzzy Logic based approach to improve the reliability of transformer differential protection, the conventional transformer differential protection commonly used a harmonic restraint principle to prevent a tripping from inrush current during initial transformer´s energization but such a principle can not performs the best optimization on tripping time. Furthermore, in some cases there may be false operation such as during CT saturation, high DC offset or harmonic containing in the line. Therefore an artificial neural network and fuzzy logic has been proposed to improve reliability of the transformer protection relay. By using EMTP-ATP the power transformer is modeled, all currents flowing ...

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구조물 손상진단을 위한 Lamb 파의 시간-역전현상에 대한 실험 (Experiment on the Time-Reversal of Lamb Waves for the Application to Structural Damage Detection)

  • 고한석;이창호;이우식
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2007년도 추계학술대회 논문집
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    • pp.913-916
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    • 2007
  • In this paper, the possibility of time reversal phenomenon was investigated in damage detection of structure. In conventional lamb wave techniques, damage is identified by comparing the measured data (baseline signals) and the current data. But this method can lead to high false signal in the intact condition of structures due to environmental conditions of the structures. So in this studying, we investigate the possibility of damage detection in the aluminum plate using the time reversal phenomenon of lamb waves.

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프레임 감산과 형태학적 필터를 이용한 드론 영상의 이동표적의 검출 (Moving Target Detection based on Frame Subtraction and Morphological filter with Drone Imaging)

  • 이민혁;염석원
    • 융합신호처리학회논문지
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    • 제19권4호
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    • pp.192-198
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    • 2018
  • 최근 드론의 활용이 여러 방면에서 급격하게 증가하고 있다. 드론은 원격으로 표적을 효율적으로 촬영할 수 있어 감시와 보안 시스템에 유용하다. 본 논문은 드론을 이용한 움직이는 차량을 검출하는 세 가지 방법을 연구한다. 배경 영상, 선행 프레임, 또는 이동 평균 프레임과 현재 프레임과의 감산 기법을 이용한 표적 검출을 비교한다. 프레임 감산 후 형태학적 필터링을 적용하여 검출률을 높이고 오보율을 감소시킨다. 또한 표적의 크기를 알고 있다는 가정 하에 영역크기 비교를 통하여 오경보 영역을 제거한다. 실험에서는 움직이는 3대의 자동차를 드론으로 촬영하여 앞서 제시한 방법에 따라 표적을 검출하고 각각 검출율과 오보율을 구하였다.

Development of 460V/225A/50㎄ Contact System in Current Limiting Molded Case Circuit Breakers

  • Park, Young-Kil;Park, Chan-Kyo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제3B권4호
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    • pp.165-172
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    • 2003
  • Low voltage circuit breakers are widely used in power distribution systems to interrupt fault current rapidly and to assure the reliability of the power supply. This paper is focused on understanding the interrupting capability, more specifically of the contacts and the arc runner, based on the shape of the contact system in the current molded case circuit breaker (hereafter MCCB). Moreover, in order to improve the interrupting capability of the circuit breaker, the estimation and analysis of the interrupting capability, based on the 3-D magnetic flux analysis, were developed. Furthermore, this paper also presents results of the estimation and analysis of the interrupting capability when applied to different model breakers. In addition, this paper analyzes the efficiency of the interrupting tests by forming false current paths consisting of a three-division cascade arc runner in the contact system. With regards to the interrupting test, there is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by the current and flux density be present. Based on the results of this study, this paper presents both computational analysis and test results for the newly developed MCCB 460V/225A/50㎄ contact system.

A novel grey TMD control for structures subjected to earthquakes

  • Z.Y., Chen;Ruei-Yuan, Wang;Yahui, Meng;Timothy, Chen
    • Earthquakes and Structures
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    • 제24권1호
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    • pp.1-9
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    • 2023
  • A model for calculating structure interacted mechanics is proposed. A structural interaction model and controller design based on tuned mass damping (TMD) was developed to control the induced vibration. A key point is to introduce a new analytical model to evaluate the properties of the TMD that recognizes the motion-dependent nonlinear response observed in the simulations. Aiming at the problem of increased current harmonics and low efficiency of permanent magnet synchronous motors for electric vehicles due to dead time effect, a dead time compensation method based on neural network filter and current polarity detection is proposed. Firstly, the DC components and the higher harmonic components of the motor currents are obtained by virtue of what the neural network filters and the extracted harmonic currents are adjusted to the required compensation voltages by virtue of what the neural network filters. Then, the extracted DC components are used for current polarity dead time compensation control to avert the false compensation when currents approach zero. The neural network filter method extracts the required compensation voltages from the speed component and the current polarity detection compensation method obtains the required compensation voltages by discriminating the current polarity. The combination of the two methods can more precisely compensate the dead time effect of the control system to improve the control performance. Furthermore, based on the relaxed method, the intelligent approach of stability criterion can be regulated appropriately and the artificial TMD was found to be effective in reducing cross-wind vibrations.

Crack Detection Method for Tunnel Lining Surfaces using Ternary Classifier

  • Han, Jeong Hoon;Kim, In Soo;Lee, Cheol Hee;Moon, Young Shik
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권9호
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    • pp.3797-3822
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    • 2020
  • The inspection of cracks on the surface of tunnel linings is a common method of evaluate the condition of the tunnel. In particular, determining the thickness and shape of a crack is important because it indicates the external forces applied to the tunnel and the current condition of the concrete structure. Recently, several automatic crack detection methods have been proposed to identify cracks using captured tunnel lining images. These methods apply an image-segmentation mechanism with well-annotated datasets. However, generating the ground truths requires many resources, and the small proportion of cracks in the images cause a class-imbalance problem. A weakly annotated dataset is generated to reduce resource consumption and avoid the class-imbalance problem. However, the use of the dataset results in a large number of false positives and requires post-processing for accurate crack detection. To overcome these issues, we propose a crack detection method using a ternary classifier. The proposed method significantly reduces the false positive rate, and the performance (as measured by the F1 score) is improved by 0.33 compared to previous methods. These results demonstrate the effectiveness of the proposed method.

환자의 의무기록 관련 의료인의 법적 지위 (Legal Status of Medical Personnel on Medical Records)

  • 이백휴
    • 의료법학
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    • 제11권2호
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    • pp.309-335
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    • 2010
  • This study is a paper reviewed legal status of medical personnel and issues of law on recently discovered medical records. As the increase of medical personnel who have gone through the administrative disposal in regards to the medical records, it is needed to examine the legal issue or dispute on the medical records under the current law. Medical records are the statement on patient's medical conditions made by the medical personnel. This records are used as important source for patient's further treatment. This becomes the communication route between the patients and the other medical personnel, and it provides the patients a right to find out their medical information. According to the Medical Service Act (Article 21), a medical personnel shall prepare respectively a record book of medical examination and treatment. And medical personnel shall make a signature. Furthermore, the medical personnel or the opener of the medical institutions must preserve the record book (including an electronic medical record). Meanwhile, the issues of a ban on false entry, additional record, revision or manipulation on the medical record have been recently on the rise. This paper briefly examined the major issues in regards to the medical records. It especially clarified the legal duty on medical records and its major-contentious-issues. At the same time, it pointed out the problems of the unreasonable over interpretation of the law. Furthermore, this suggested the guidelines for the further discussion and review.

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Evidence for U.S. Preventive Services Task Force (USPSTF) Recommendations Against Routine Mammography for Females between 40-49 Years of Age

  • Karimi, Parisa;Shahrokni, Armin;Moradi, Sedighe
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권3호
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    • pp.2137-2139
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    • 2013
  • Breast cancer is the most common cancer among females, worldwide, accounting for 22.9% of all cancers (excluding non-melanoma skin cancer) in females. Mammography is a sensitive (77-95%) and specific (94-97%) screening method for breast cancer. Previously, females between the 40-50 years old were recommended to have mammograms every one to two years. However, based on current evidence, in 2009, USPSTF recommended that the decision to start regular, biennial screening mammography for females younger than 50 years should be an individual decision and take patient context into account, including the patient's values regarding specific benefits and harms. This decision was based on findings regarding radiation exposure, false-positive and false-negative rates, over-diagnosis, and pain and psychological responses. The goal of this paper is to focus on evidence for updating the U.S. Preventive Services Task Force (USPSTF) recommendation against routine mammography for females between 40-49 years of age.

음성 패킷을 이용한 채널의 에러 정보 전달 (Transmission of Channel Error Information over Voice Packet)

  • 박호종;차성호
    • 한국음향학회지
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    • 제21권4호
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    • pp.394-400
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    • 2002
  • 디지털 음성 통신에서 송신하는 음성 패킷의 전송 에러율을 알면 송신 채널 상황에 적합한 압축 동작을 통하여 전체 통신의 품질을 향상시킬 수 있다. 그러나 현재의 이동통신과 인터넷 통신에서는 음성 패킷의 전송 에러정보를 알려주는 프로토콜이 지원되지 않는다. 본 논문에서는 이를 해결하기 위하여 채널의 전송 에러 정보를 음성 패킷에 삽입하여 실시간으로 전달하는 방법을 제안한다. 제안하는 채널 에러 정보 삽입 방법은 ACELP (algebraic code-excited linear predictin) 코드벡터의 펄스 위치의 상관 관계를 이용하며, 이를 통하여 추가정보 삽입에 의한 음질 저하를 막고 오인식율을 줄일 수 있다. 다양한 음성 데이터를 이용하여 제안한 방법의 성능을 측정하였으며 음질의 저하가 거의 발생하지 않고 정보의 검출 능력과 오인식율에서 만족할 만한 성능을 가지는 것을 확인하였다.

기능성 유제품의 생산 현황 및 관리제도 - 미국.유럽을 중심으로 - (Current Status and Regulation Issues of the Functional Dairy Products in European Countries and the United States of America)

  • 윤성식;송태석;전상록;박다정;박정민;운재호;임경종;김진만
    • Journal of Dairy Science and Biotechnology
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    • 제26권2호
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    • pp.9-22
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    • 2008
  • This work has been conducted as a part to set up the regulations and the scientific evaluation systems for the functional dairy products with health claims in Korea. Toward this end, current regulations, requirements, and all kinds of provisions related to the functional dairy products overseas were taken into accounts and feasible recommendations of new initiatives on the current regulations as well. By doing so, not only protecting hopefully the innocent consumers from the false labeling statements and fake advertisements, but also eventually to revitalize the stagnated domestic dairy industries. Currently, functional daily products are simply regarded as "Dietary Supplements" in the United States, and subjected to the regulations under the Dietary Supplement Health and Education Act, established m 1994. Manufacturers and sales distributors should notify their products to the FDA, which is in charge of the dietary supplements on nutrition and labeling, in advance when they start marketing a new dietary ingredient or any foods containing it in the States. For EU countries, there exists keen interests about the functional food products between the member countries of the European Union even though the products are categorized into "Food Supplements" similar to those in the United States. Therefore, they maintain a cautious attitude in applying the health claims to the functional food products. On the other hand, under the Japanese health food system, functional foods are qualified to the functional health foods in terms of legal status as long as any traditional foods can meet the legal standards in its effectiveness, safety as well as quality, along with significant scientific evidences related to the products, thus categorized into "Foods for Specified Health Uses and "Foods with Nutrient Function Claims". Through this study, we may have some expectations and potential utilizations as follows: Legal regulations of dietary supplements especially for the dairy products will be implemented by the outcomes of this research and proposed a tentative amendment of functional ingredients for the sake of consumer protection from the false advertisements and overstatement labeling. Current regulations on the animal foods processing and advertisements will be amended and supplemented in order to revitalize the current downturn dairy sales and to harmonize the international Codex recommendations. The results obtained from this study will make the consumers a wise selection of the dairy products with health claims and be utilized for consumer education and advertisement of the functional products as well.

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