• Title/Summary/Keyword: fixed point observation

Search Result 36, Processing Time 0.022 seconds

Characteristics of Female College Students Clothing in Campus with Fixed Point Observation - Focusing in Seoul - (정점관측법에 의한 여대생들의 착의특성 - 서울의 여대생을 중심으로 -)

  • Choi, Young-Soon;Park, Mi-Ae
    • Fashion & Textile Research Journal
    • /
    • v.7 no.4
    • /
    • pp.401-406
    • /
    • 2005
  • The objective of this field research is to determine consumer's fashion sense and provide helpful information to manufacturers when planning designs and merchandizing strategies. This study's purpose was to observe what was being worn, colors and tones. The method of research was fixed point observation using digital photos. The subjects of the research were female college students, 18-22 years old. The T-shirt has become the representative item for casual and comfortable wear by the female college students. Pants and blue jeans were worn more often than skirts as a lower garment. This shows that the students think about their activities when choosing a lower garment. The majority of these students chose clothing that functioned well for their school activities. Among students that wore skirts about half wore a functional knee length while the other half wore a more fashionable mini-skirt. These students appear to care about both fashion and function. Blue was especially popular, with 70.4% of all lower garments being blue. This effect makes the body look thinner and may be one reason why blue is so popular. White is a popular color as an upper garment. White upper garments are easily matched with any color, while blue upper garments coordinate well with similarly colored blue lower garments. The distribution of upper garment color is significantly influenced by the seasons. Blue jean tones were many and varied, while upper garments were mostly weak tones and bright tones of pale, light and soft.

Improving the performance of PV system using the N-IC MPPT methods (N-IC MPPT방법을 이용한 태양광 발전시스템의 성능개선)

  • Seo, Tae-Young;Ko, Jae-Sub;Kang, Sung-Min;Kim, Yu-Tak;Chung, Dong-Hwa
    • Proceedings of the KIEE Conference
    • /
    • 2015.07a
    • /
    • pp.958-959
    • /
    • 2015
  • This paper proposes adaptive incremental conductance(A-IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. Conventional Perturbation & Observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, this paper proposes N-IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve tracking speed and accuracy, when operating point is far from maximum power point(MPP), step size uses maximum value and when operating point is near from MPP, step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional IC MPPT algorithm.

  • PDF

MPPT Control of Photovoltaic System using HBPI Controller (HBPI 제어기를 이용한 태양광발전 시스템의 MPPT 제어)

  • Ko, Jae Sub;Chung, Dong-Hwa
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.12
    • /
    • pp.1864-1871
    • /
    • 2012
  • This paper proposes the hybrid proportional integral(HBPI) controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation and influence of a shadow. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional constant voltage(CV), perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, in order to solve these problems, this paper proposes HBPI controller that is adjusted gain of conventional PI control using fuzzy control, and the maximum power point tracks using this controller. The validity of the controller proposed in this paper proves through the results of the comparisons.

Variation of Position Accuracy due to Observation Time and Baseline Distance in GPS Survey (GPS 측량에서의 관측시간과 기선거리에 따른 좌표정확도 비교)

  • Kim, Du-Sik;Park, Kwan-Dong;Lee, Sa-Hyung;Lee, Ho-Seok
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
    • /
    • 2010.04a
    • /
    • pp.187-190
    • /
    • 2010
  • GPS survey came into wide use, but there are inefficient parts in related laws and regulations. Especially, to get GPS surveying results under 1.5cm permissible error the observation time must be longer than 8 hours in triangulation points surveying regulations. However, GPS surveying technology is developing now, so results could be acceptable under 4 hours observation time. Therefore, this study made a stable standard of observation time in GPS survey by comparing the errors due to observation time, and used PAJU, DOND and YANP's GPS data and 6 cadastral points' survey data. Also, to analyze the variations of results due to baseline distance, applied each GPS site as a fixed point and compared the positions. As a result, the stable satisfactory results were calculated under 4 hour survey, when the baseline distances were under 30km.

  • PDF

Minimum risk point estimation of two-stage procedure for mean

  • Choi, Ki-Heon
    • Journal of the Korean Data and Information Science Society
    • /
    • v.20 no.5
    • /
    • pp.887-894
    • /
    • 2009
  • The two-stage minimum risk point estimation of mean, the probability of success in a sequence of Bernoulli trials, is considered for the case where loss is taken to be symmetrized relative squared error of estimation, plus a fixed cost per observation. First order asymptotic expansions are obtained for large sample properties of two-stage procedure. Monte Carlo simulation is carried out to obtain the expected sample size that minimizes the risk and to examine its finite sample behavior.

  • PDF

The MPPT Control of Photovoltaic System using the Fuzzy PI Controller (퍼지 PI 제어기를 이용한 태양광 발전시스템의 MPPT 제어)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.28 no.2
    • /
    • pp.9-18
    • /
    • 2014
  • This paper proposes the fuzzy PI controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, this paper proposes the MPPT control using the fuzzy PI controller that can be improve a MPPT control performance. The fuzzy PI controller is adjusted a input of PI controller by fuzzy control and compensated a cumulative error of fuzzy control by PI controller. The fuzzy PI MPPT control is compared to conventional PO and IC MPPT method for various temperature and radiation condition. This paper proves the validity of the fuzzy PI controller using these results.

The MPPT Control oh Photovoltaic System using FVSS-PO Method (FVSS-PO를 이용한 태양광 발전시스템의 MPPT 제어)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.27 no.11
    • /
    • pp.20-26
    • /
    • 2013
  • This paper proposes the maximum power point tracking(MPPT) control of photovoltaic system using fuzzy based variable step size perturbation & observation(FVSS-PO) method. Conventional PO and incremental conductance(IC)MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, the fixed step size can't be satisfying both the tracking speed and the tracking accuracy. This paper proposes FVSS-PO MPPT algorithm that adjusts automatically step size of PO by fuzzy control according to operating conditions. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO MPPT algorithm.

MPPT Control of Photovoltaic using Variable IC Method (가변 IC 방법을 이용한 태양광 발전의 MPPT 제어)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.26 no.8
    • /
    • pp.27-34
    • /
    • 2012
  • This paper proposes variable incremental conductance(IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small step size reduces a tracking error in the steady state but slows a tracking speed in the transient state. Also, a large step size is fast a tracking speed but increases a tracking error. Therefore, this paper proposes variable IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve a tracking speed and accuracy, when operating point is far from the maximum power point(MPP), the step size uses maximum value and when a operating point is near from the MPP, the step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO and IC MPPT algorithm.

Observation of Fracture Strengths According to the Core Materials for All Ceramic Bridge (전부도재교의치의 코어재료에 따른 파절강도 관찰)

  • Chung, In-Sung;Kim, Chi-Young
    • Journal of Technologic Dentistry
    • /
    • v.32 no.4
    • /
    • pp.351-356
    • /
    • 2010
  • Purpose: The purpose of this study was to evaluate the fracture strength between the core and veneering ceramic according to 2 core materials, In-Ceram Alumina and In-Ceram Zirconia, fabricated by electro ceramic layering technique. 2 different fixed partial denture cores of three units were veneered by veneering ceramic(Ceranion, Noritake) (n=10). Methods: The fracture strengths between the core and veneering ceramic were measured through the 3 point bending test. The interfaces between the core and veneering ceramic were observed with the X-ray dot mapping of EPMA. Results: The result of fracture strength was observed that IZP group, In-Ceram Zirconia core, had higher fracture strength. IPA group, In-Ceram Alumina core, had fracture strength of 359.9(${\pm}$86.2) N. IZP group, In-Ceram Zirconia core, had fracture strength of 823.2(${\pm}$243.0) N. X-ray dot mapping observation showed that a major element in the core and veneering ceramic of IPA group was alumina and silica, respectively. No binder was observed in interfaces between the core and veneering ceramic, and no ion diffusion or transition was observed between the core and veneering ceramic. However, apparent ion diffusion or transition was observed between the core and veneering ceramic of IZP group.

A Study on the Determination of 3-Dimensional Position by Trilateration (삼변측량에 의한 3차원 위치결정에 관한 연구)

  • 박운용;이종출;김희규
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.7 no.1
    • /
    • pp.1-9
    • /
    • 1989
  • Up to date, the ditermination of three dimentional position is performed sperately by horizontal and vertical adjustment. The purpose of this study is to determine simultaneously three dimentional coordinates of one unknown point by measuring only three slope distances from one unknown point to three fixed points. In this study, the adjustment problem for measurement values inclading redundancy is solved by observation equation and condition equation, and also the characteristic of these two analysis methods is studied and investigated.

  • PDF