• 제목/요약/키워드: Step-Down Method

검색결과 183건 처리시간 0.033초

An Algorithm for a pose estimation of a robot using Scale-Invariant feature Transform

  • 이재광;허욱열;김학일
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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    • pp.517-519
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    • 2004
  • This paper describes an approach to estimate a robot pose with an image. The algorithm of pose estimation with an image can be broken down into three stages : extracting scale-invariant features, matching these features and calculating affine invariant. In the first step, the robot mounted mono camera captures environment image. Then feature extraction is executed in a captured image. These extracted features are recorded in a database. In the matching stage, a Random Sample Consensus(RANSAC) method is employed to match these features. After matching these features, the robot pose is estimated with positions of features by calculating affine invariant. This algorithm is implemented and demonstrated by Matlab program.

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난류유동해석을 통한 환기효율의 수치해석적 연구 (Numerical Analysis of Ventilation Effectiveness using Turbulent Airflow Modeling)

  • 한화택
    • 설비공학논문집
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    • 제4권4호
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    • pp.253-262
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    • 1992
  • A numerical procedure is introduced to calculate local ventilation effectiveness using the definitions of local decay rate and local mean age. A low Reynolds number $k-{\varepsilon}$ model is implemented to calculate steady state turbulent velocity distributions, and a step-down method is used to calculate transient concentration distributions. Simulations are carried out for several different values of air change rates and several different diffuser angles in a two-dimensional model of a half scale office room. The results show that the local ventilation effectiveness within a room could vary significantly from one location to another. The nominal air change rate based on the assumption of complete mixing of room air does not provide the local ventilation effectiveness information. It is numerically proved that the local mean age distribution obtained from the transient calculation is equivalent to the steady state concentration distribution with homogeneously distributed contaminant sources.

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SRM의 진동.소음의 저감을 위한 직류여자 전류방식에 관한 연구 (Study on the D.C Excitation Commutation Method of SRM for Reduction of Vibration/Acoustic Noise)

  • 오석규;추영배;이일천;황영문
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 1999년도 전력전자학술대회 논문집
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    • pp.147-150
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    • 1999
  • SRM drives generate large vibration and acoustic noise because it is commutated individually by step pulse m.m.f on each phase pole. The frequency or motor speed of peak vibrations and acoustic noises is coincided with the natural resonant frequency of the magnetic structure and frame material. And this radial vibration force is induced on the phase commutation region. This paper suggest the new electromagnetic structure of SRM with auxiliary commutation winding excited d.c e.m.f.. This phase- commutating winding is coupled magnetically between one phase winding and the vibrating force is falled down. As a result, SRM with d.c exciting commutation winding is very useful to reduce vibration and acoustic noise of SRM drive.

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환기방식별 실내 환기효율 분석에 관한 실험적 연구 (An Experimental Analysis of Ventilation Effectiveness using Tracer Gas)

  • 강태욱
    • Journal of Advanced Marine Engineering and Technology
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    • 제30권2호
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    • pp.260-266
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    • 2006
  • A tracer gas technique based on ASTM Standard E741-83 was used to measure ventilation performances in a model chamber ($0.84m{\times}0.68m{\times}0.7m$) with an exhaust fan and a supply fan. Experiments were performed for the ventilation effectiveness on three types of mechanical ventilation systems. For all cases. higher ventilation effectiveness was found in the type to ventilation system due to shorter residual time of air compared to type 1 and type 3.

정상 및 기억손상 유도 동물의 수동회피반응에 대한 홍삼 사포닌의 효과 (Effects of Red Ginseng Saponin on Normal and Scopolamine-induced Memory Impairment of Mice in Passive Avoidance Task)

  • 진승하;경종수
    • Journal of Ginseng Research
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    • 제20권1호
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    • pp.7-14
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    • 1996
  • This study was performed to examine the effect of red ginseng total saponin and extract on memory in mice using one trial step-down type passive avoidance method. Red ginseng total saponins (No. 1: PD/PT ratio=1.24, No. 2: PD/PT ratio=1.47) were prepared with the different mixing ratio by using the parts of red ginseng. In single administration of total saponin No. 1 (100 mg/ kg, bw) or No. 2 (50 mg/kg, bw) increased the latency time as compared with control group but was not statistically significant. Treatment of total saponin No. 1 (50 mg/kg, bw) for 10 days produced an increase of latency time but was not statistically significant. In scopolamine-induced memory deficient mice total saponin No. 1 (50 mg/kg, bw) and No. 2 (100 mg/kg, bw) significantly improved the latency time. These results show that red ginseng total saponin may improve the memory of sco-polamine-induced memory deficient mice and have nootropic activity.

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강정과 산자류 제조에 관한 실험조리적 연구 (II) - 건조와 튀기는 과정에 따른 강정과 산자의 질감에 대하여 - (Experimental Study on Gangjung and Sanja (II) - Textural Change in Gangjung and Sanja by Drying and frying Method -)

  • 김태홍
    • 대한가정학회지
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    • 제20권2호
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    • pp.119-125
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    • 1982
  • Based on the selected controlled receipe, drying and frying processes were varied inculding time and temperature. According to the panel test and measurement with a texturometer on the products of different drying and frying conditions, the highly acceptable best product was the one prepared as follows. It was placed in the oven at $45^{\circ}C$ for 5 minutes and then at $23^{\circ}C$for 15 minutes. After turning upside down, this drying step was repeatedly continued for 5 hours. It was also dipped into oil at $14^{\circ}C$ for 1 minute, soaked in oil at $120^{\circ}C$for 2 minutes and then fried in oil at $190^{\circ}C$for 2 minutes. The studies using a texturometer showed the products with high acceptability in the panel test had brittleness of 1.3-2cm and number of peaks 4-6. The optimum drying times is considered as 3 hours since there was no significant difference among the products of 3 to 5 hours drying time.

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바닥취출 공조공간에서 급기온도 및 급기풍속이 환기효율에 미치는 영향 (Effect of supply air temperature and airflow rate on ventilation effectiveness in an underfloor air conditioning space)

  • 정광섭;한화택;홍승재
    • 설비공학논문집
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    • 제10권5호
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    • pp.640-648
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    • 1998
  • A numerical study has been conducted to investigate the effect of inflow supply air temperature and velocity on ventilation effectiveness in an underfloor air conditioning space. A low Reynolds number k-$\varepsilon$ model is implemented to calculate steady state turbulent velocity distributions. A step-down injection method is used to calculate local and room mean ages from transient concentrations based on the concept of the age of air. Results show that there is a significant effect of Archimedes number on ventilation effectiveness especially for cooling conditions. Reynolds number shows relatively minor effect on velocity distribution and ventilation effectiveness especially for isothermal and heating conditions. It can be concluded that underfloor air conditioning system provides good ventilation characteristics for cooling conditions because of temperature stratification in the space.

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얼굴추적 카메라 구동에 사용된 스텝모터의 속도제어에 관한 연구 (A study on the speed control of the step motor for driving face-tracking camera)

  • 이종배;성하경;김영욱;정재훈;범진환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.230-232
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    • 2001
  • The camera system we researched has two stepping motors for the pan and tilt operation, and the human face tracking algorithm. Recently, this kind of the camera is used in PC communication, telecommunication vision meeting and tele-lecture. This paper discusses the smooth speed control method of this camera when the face is moved to up, down, left and right direction. We used a mean shift algorithm for the face-tracking, proposed the speed control algorithm using a fuzzy logic and certified this characteristics with the experiment.

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마이크로포텐시오미터를 이용한 저전압 교류-직류 변환기의 평가기술 (Evaluation Technique of the Low Voltage AC-DC Transfer Standard using Micropotentiometer)

  • 권성원;정재갑;이상화;김한준;김문석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.1704-1705
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    • 2007
  • A step-down procedure employing low voltage thermal transfer standard(LVTS) and micropotentiometer is described for the establishing the ac low voltage standards in the range of 2 mV to 200 mV below 1 MHz. Techniques are given for measuring input impedance with insertion method and calculating the loading error for the ac-dc transfer difference of the LVTS.

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공진모드의 변화에 따른 압전변압기의 특성에 관한 연구 (A Study on Design and Analysis of Piezoelectric Transformer for Resonance Mode)

  • 정현호;이상기;박태곤;김명호;이원재
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 하계학술대회 논문집
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    • pp.432-435
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    • 2000
  • This paper present a new sort of multilayer piezoelectric ceramic transformer for the application to AC-adapters. This piezoelectric transformers operate in the second and third length extensional vibration mode. And the output performance of two types of piezoelectric transformers are compared by ANSYS, which is one of the FEM analysis program. As a result the minimum displacement was occurred at the two points in second length extensional vibration mode and three point in third length extensional vibration mode. One is the middle of input and the other is middle of output parts. And output voltage was inversely decreased by increasing number of output layers. Also The third mode type is shown higher power transition ratio than the second mode type.

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