• 제목/요약/키워드: Phase average

검색결과 2,215건 처리시간 0.026초

단상 능동 전력 조절 장치를 위한 새로운 제어기법 (A New Control Method for Single-Phase Active Power Line Contioners)

  • 서영조
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2000년도 전력전자학술대회 논문집
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    • pp.155-158
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    • 2000
  • A new control method for single-phase shunt active power line conditioners(APLC's) operated under zero average power consumption is proposed in this paper. The amplitude of the sinusoidal source current which is in-phase with the source voltage can be determined from the average value of the instantaneous load power. Then the command current for the shunt APLC is obtained by subtraction the source current from the load current. Neither bulky filter nor time-consuming computation is required. The shunt power compensator supplies all the harmonics of he load current and the source only supplies the fundamental component,. Experimental results on a prototype verify the feasibility of the presented scheme,

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수명분포가 Phase-Type인 수리불가능한 제품의 보증정책 (Warranty Policies for Non-Repairable Products with Phase-type Lifetime Distributions)

  • 김호균
    • 품질경영학회지
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    • 제24권1호
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    • pp.1-9
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    • 1996
  • Ritchken(1985) analyzes free replacement and pro-rata warranty policies for products receiving renewable warranies. He shows that for constant failure rates pro-rata warranty policies are more attractive to risk-averse manufacturers than shorter term free replacement policies that result in the same average warranty cost. This paper considers the case when product lifetimes distributions are of phase-type. When this is so, Ritchken's performance measures can be simplified considerably. It is found, that irrespective of the pattern of failure rates, pro-rata warranty policies are preferable to free replacement policies. But the warranty period of the equivalent free replacement policy decreases and then increases, as product reliability(the average time between failures) increases.

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자석 형상 최적화를 통한 축방향 이상 횡자속형 전동기의 토크 특성 향상에 관한 연구 (Improvement of Torque Characteristics of a Rotatory Two-phase Transverse Flux Machine Optimizing the Shape of Rotor Pole)

  • 안희태;장건희
    • 한국소음진동공학회논문집
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    • 제19권10호
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    • pp.1003-1011
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    • 2009
  • Transverse flux machine(TFM) has been developed to drive a machine of large input power at low-speed. However, it has complicated structure and large torque ripple due to its inherent structure. In this paper the characteristics of torque of a rotatory two-phase TFM are analyzed by using the 3-dimensional finite element method and optimal design. This research shows that one of the effective design variables is the skew angle of permanent magnet. The skew angles of permanent magnet are optimized by using a genetic algorithm. It also shows that the proposed optimal skew magnet not only increases average torque but also decreases torque ripple of a rotatory two-phase TFM.

광학적 비접촉 측정에 의한 구조물 해석의 화상처리 계측 시스템 개발에 관한 연구 (A Study on the Development of Image Processing Measurement System on the Structural Analysis by Optical Non-contact Measurement)

  • 김경석
    • 한국생산제조학회지
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    • 제8권6호
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    • pp.78-83
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    • 1999
  • This study discusses a non-contact optical technique, electronic speckle pattern interformetry(ESPI), that is well suited for in-plane and out-of-plane deformation measurement. However, the existing ESPI methods that are based on dual-exposure, real-time and time-average method have difficulties for accurate measurement of structure, due to irregular intensity and shake of phase. Therefore, phase shifting method has been proposed in order to solve this problem. About the method, the path of reference light in interferometry is shifted and added to least square fitting method to make the improvement in distinction and precision. This proposed method is applied to measure in -plane displacement that is compared with the previous method. Also, Used as specimen AS4/PE따 [30/=30/90]s was analyzed by ESPI based on real-time to determine the characteristics of vibration under no-load and tension. These results are quantitatively compared with those of FEM analysis inmode shapes.

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確率密度函數와 電導 Prode信號에 의한 垂直二相流의 流動樣式特性 (Flow pattern characteristics in vertical two phase flow by PDF and signals from conductance probe)

  • 손병진;김인석;이진
    • 대한기계학회논문집
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    • 제10권6호
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    • pp.814-822
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    • 1986
  • 본 연구에서는 이러한 점에 착안하여 비가열수직이상유동계에서 전도Probe 를 이용하여 시간평균보이드율을 측정하여 이들로부터 통계적으로 처리된 확률밀도함 수(PDF)분포와 이와 관련된 일련의 모우멘트계산을 시도 하므로써 유동양식과 천이특 성에 대하여 객관적이고 체계적인 해석을 하였다. 또한 학계 및 산업계에서는 측정 기구의 단순화가 요구되므로 전도Probe의 출력신호를 분석하여 유동양식에 따르는 특 성을 아울러 구명하였다.

환경이 조절되는 Chamber 내에서 Environmental Tobacco Smoke의 생성과 감소 현상 (Generation and Decay Phenomena of Environmental Tobacco Smoke in Controlled Experimental Atmosphere Chamber)

  • 이문수;나도영;안기영;이규서
    • 한국연초학회지
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    • 제18권2호
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    • pp.170-176
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    • 1996
  • This paper describes the generation and decay phenomena of gas, vapor and particulate phase components of environmental tobacco smoke in 18 m3 controlled experimental atmosphere chamber. Real time-weighted average concentration ratios of markers were determinated at no ventilation rates and sampling durations of starting to smoking 45 min. Average concentration of major ETS markers was no significant on the mainstream smoke contents of commercial cigarette and decay ratios were dependent on first order kinetic. RSP/nicotine, solanesol and 3-EP were good predictors of ETS concentration in the public indoor field. The concentration ratio of vapor phase and particulate phase components is highly variable to assessment of indoor air quality with ETS. Key words : ETS, chamber study, ETS markers.

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액상소결의 기공채움 이론과 미세구조 발달 (Pore Filling Theory of Liquid Phase Sintering and Microstrcture Evolution)

  • 이성민
    • 한국분말재료학회지
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    • 제6권1호
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    • pp.81-87
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    • 1999
  • Based on the pore filling theory, the microstructure evolution during liquid-phase sintering has been analyzed in terms of interrelationship between average grain size and relative density. For constant liquid volume fraction, the microsturucture trajectories reduced to a single curve in a grain size(x)-density(y) map, regardless of grain growth constant. The slope of curves in the map was inversely proportional to average pore size, while it increased fapidly with liquid volume fraction. Increase in pore volume fraction retarded the densification considerably, but showed marginal effect on the slope. The activation energy of densification was predicted to be the same as that of grain growth as long as the liquid volume fraction is constant for any temperature range studied. The present analyses on microstricture evolution may demonstrate the usefulness of pore filling theory and provide a guideline for process optimization of liquid-phase sintering.

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Malaysian Name-based Ethnicity Classification using LSTM

  • Hur, Youngbum
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제16권12호
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    • pp.3855-3867
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    • 2022
  • Name separation (splitting full names into surnames and given names) is not a tedious task in a multiethnic country because the procedure for splitting surnames and given names is ethnicity-specific. Malaysia has multiple main ethnic groups; therefore, separating Malaysian full names into surnames and given names proves a challenge. In this study, we develop a two-phase framework for Malaysian name separation using deep learning. In the initial phase, we predict the ethnicity of full names. We propose a recurrent neural network with long short-term memory network-based model with character embeddings for prediction. Based on the predicted ethnicity, we use a rule-based algorithm for splitting full names into surnames and given names in the second phase. We evaluate the performance of the proposed model against various machine learning models and demonstrate that it outperforms them by an average of 9%. Moreover, transfer learning and fine-tuning of the proposed model with an additional dataset results in an improvement of up to 7% on average.

Influence of ultrasonic impact treatment on microstructure and mechanical properties of nickel-based alloy overlayer on austenitic stainless steel pipe butt girth joint

  • Xilong Zhao;Kangming Ren;Xinhong Lu;Feng He;Yuekai Jiang
    • Nuclear Engineering and Technology
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    • 제54권11호
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    • pp.4072-4083
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    • 2022
  • Ultrasonic impact treatment (UIT) is carried out on the Ni-based alloy stainless steel pipe gas tungsten arc welding (GTAW) girth weld, the differences of microstructure, microhardness and shear strength distribution of the joint before and after ultrasonic shock are studied by microhardness test and shear punch test. The results show that after UIT, the plastic deformation layer is formed on the outside surface of the Ni-based alloy overlayer, single-phase austenite and γ type precipitates are formed in the overlayer, and a large number of columnar crystals are formed on the bottom side of the overlayer. The average microhardness of the overlayer increased from 221 H V to 254 H V by 14.9%, the shear strength increased from 696 MPa to 882 MPa with an increase of 26.7% and the transverse average residual stress decreased from 102.71 MPa (tensile stress) to -18.33 MPa (compressive stress), the longitudinal average residual stress decreased from 114.87 MPa (tensile stress) to -84.64 MPa (compressive stress). The fracture surface has been appeared obvious shear lip marks and a few dimples. The element migrates at the fusion boundary between the Ni-based alloy overlayer and the austenitic stainless steel joint, which is leaded to form a local martensite zone and appear hot cracks. The welded joint is cooled by FA solidification mode, which is forming a large number of late and skeleton ferrite phase with an average microhardness of 190 H V and no obvious change in shear strength. The base metal is all austenitic phase with an average microhardness of 206 H V and shear strength of 696 MPa.

최소자승법을 이용한 Switched Reluctance Motor의 최대 평균토오크 제어 (Maximization average torque control of Switched Reluctance Motor using least square method)

  • 김춘삼;정연석
    • 조명전기설비학회논문지
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    • 제16권5호
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    • pp.61-65
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    • 2002
  • SRM 토크는 인덕턴스 프로파일과 전류에 의해 발생한다. 발생한 SRM 토크는 전류제어시 turn-off 각을 제어함으로써 최대화 할 수 있고, 본 논문에서는 최소자승법을 이용하여 구한 함수를 통해 Turn-off 각을 제어할 수 있는 방안을 제안하였다. 시뮬레이션은 3상 6/4극 SRM을 대상으로 하였고, 제안한 방법에 의해 최대 평균토크가 됨을 시뮬레이션을 통해 증명하였다.