• Title/Summary/Keyword: line sampling

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SAMPLING EXPANSION OF BANDLIMITED FUNCTIONS OF POLYNOMIAL GROWTH ON THE REAL LINE

  • Shin, Chang Eon
    • Communications of the Korean Mathematical Society
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    • v.29 no.2
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    • pp.379-385
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    • 2014
  • For a bandlimited function with polynomial growth on the real line, we derive a nonuniform sampling expansion using a special bandlimited function which has polynomial decay on the real line. The series converges uniformly on any compact subsets of the real line.

Development of multi-line laser vision sensor and welding application (멀티 라인 레이저 비전 센서를 이용한 고속 3차원 계측 및 모델링에 관한 연구)

  • 성기은;이세헌
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.169-172
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    • 2002
  • A vision sensor measure range data using laser light source. This sensor generally use patterned laser which shaped single line. But this vision sensor cannot satisfy new trend which feeds foster and more precise processing. The sensor's sampling rate increases as reduced image processing time. However, the sampling rate can not over 30fps, because a camera has mechanical sampling limit. If we use multi line laser pattern, we will measure multi range data in one image. In the case of using same sampling rate camera, number of 2D range data profile in one second is directly proportional to laser line's number. For example, the vision sensor using 5 laser lines can sample 150 profiles per second in best condition.

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High speed seam tracking system using vision sensor with multi-line laser (다중 레이저 선을 이용한 비전 센서를 통한 고속 용접선 추적 시스템)

  • 성기은;이세헌
    • Proceedings of the KWS Conference
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    • 2002.05a
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    • pp.49-52
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    • 2002
  • A vision sensor measure range data using laser light source, This sensor generally use patterned laser which shaped single line. But this vision sensor cannot satisfy new trend which needs faster and more precise processing. The sensor's sampling rate increases as reduced image processing time. However, the sampling rate can not over 30fps, because a camera has mechanical sampling limit. If we use multi line laser pattern, we will measure multi range data in one image. In the case of using same sampling rate camera, number of 2D range data profile in one second is directly proportional to laser line's number. For example, the vision sensor using 5 laser lines can sample 150 profiles per second in best condition.

  • PDF

High speed seam tracking using multi-line laser vision sensor (멀티 라인 레이저 비전 센서를 이용한 고속 용접선 추적 기술)

  • 성기은;이세헌
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.584-587
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    • 2002
  • A vision sensor measure range data using laser light source. This sensor generally use patterned laser which shaped single line. But this vision sensor cannot satisfy new trend which needs laster and more precise processing. The sensor's sampling rate increases as reduced image processing time. However, the sampling rate can not over 30fps, because a camera has mechanical sampling limit. If we use multi line laser pattern, we will measure multi range data in one image. In the case of using same sampling rate camera, number of 2D range data profile in one second is directly proportional to laser line's number. For example, the vision sensor using 5 laser lines can sample 150 profiles per second in best condition.

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A study on the Forest inventory work (삼림자원조사법(森林資源調査法)의 연구(硏究))

  • Kim, Kap Duk
    • Journal of Korean Society of Forest Science
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    • v.5 no.1
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    • pp.10-15
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    • 1966
  • 1) The purpose of this study was to compare the forest survey by ground method with that by aerial photo method. 2) In this study, the forest type map was made by use of the radial line plotter and radial line triangulation method. 3) The difference between the area found by the forest type map above mentioned and that by compass surveying on the ground was none-significant. 4) On aerial photo the stratification was carried out very easily. 5) The following sampling methods were applied : line plot method, representative sampling method and stratified random sampling on the aerial photo. 6) In confirming sampling point the line plot method and the representative sampling method were easier than another. 7) As to stands volume the maximum value was given by stratification, and the minimum by line plot method.

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A Comparative Case Study on Sampling Methods for Cost-Effective Forest Inventory: Focused on Random, Systematic and Line Sampling (비용 효율적 표준지 조사를 위한 표본추출방법 비교 사례연구: 임의추출법, 계통추출법, 선상추출법을 중심으로)

  • Park, Joowon;Cho, Seungwan;Kim, Dong-geun;Jung, Geonhwi;Kim, Bomi;Woo, Heesung
    • Journal of Korean Society of Forest Science
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    • v.109 no.3
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    • pp.291-299
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    • 2020
  • The purpose of this study was to propose the most cost-effective sampling method, by analyzing the cost of forest resource investigation per sampling method for the planned harvesting area of in Chunyang-myeon, Byeonghwa-gun, Gyeongsangbuk-do, Korea. For this study, three sampling methods were selected: random sampling method, systematic sampling method, and line transect method. For each method, sample size, hourly wage, number of sample points, survey time, travel time, the sample error rate of the estimated average volume, and the desired sampling error rate were used to calculate the cost of forest resource inventories. Thus, 10 sampling points were extracted for each sampling method, and the factors required for cost analysis were calculated via a field survey. As a result, the field survey cost per ha using the random sampling method was found to be have the lowest cost, regardless of the desired sampling error rate, followed by the systematic sampling method, and the line transect method.

Variable Sampling Inspection with Screening When Lot Quality Follows Mixed Normal Distribution

  • Suzuki, Yuichiro;Takemoto, Yasuhiko;Arizono, Ikuo
    • Industrial Engineering and Management Systems
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    • v.8 no.3
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    • pp.131-138
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    • 2009
  • The variable sampling inspection scheme with screening for the purpose of assuring the upper limit of maximum expected surplus loss after inspection has been proposed. In this inspection scheme, it has been assumed that a product lot consists of products manufactured through a single production line and lot quality characteristics follow a normal distribution. In the previous literature with respect to inspection schemes, it has been commonly assumed that lot quality characteristics obey a single normal distribution under the condition that all products are manufactured in the same condition. On the other hand, the production line is designed in order that the workload of respective processes becomes uniform from the viewpoint of line balancing. One of the solutions for the bottleneck process is to arrange the workshops in parallel. The lot quality characteristics from such a production line with the process consisting of some parallel workshops might not follow strictly the single normal distribution. Therefore, we expand an applicable scope of the above mentioned variable sampling inspection scheme with screening in this article. Concretely, we consider the variable sampling inspection with screening for the purpose of assuring the upper limit of average outgoing surplus quality loss in the production lots when the lot quality follows the mixed normal distribution.

Parallel processing in structural reliability

  • Pellissetti, M.F.
    • Structural Engineering and Mechanics
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    • v.32 no.1
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    • pp.95-126
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    • 2009
  • The present contribution addresses the parallelization of advanced simulation methods for structural reliability analysis, which have recently been developed for large-scale structures with a high number of uncertain parameters. In particular, the Line Sampling method and the Subset Simulation method are considered. The proposed parallel algorithms exploit the parallelism associated with the possibility to simultaneously perform independent FE analyses. For the Line Sampling method a parallelization scheme is proposed both for the actual sampling process, and for the statistical gradient estimation method used to identify the so-called important direction of the Line Sampling scheme. Two parallelization strategies are investigated for the Subset Simulation method: the first one consists in the embarrassingly parallel advancement of distinct Markov chains; in this case the speedup is bounded by the number of chains advanced simultaneously. The second parallel Subset Simulation algorithm utilizes the concept of speculative computing. Speedup measurements in context with the FE model of a multistory building (24,000 DOFs) show the reduction of the wall-clock time to a very viable amount (<10 minutes for Line Sampling and ${\approx}$ 1 hour for Subset Simulation). The measurements, conducted on clusters of multi-core nodes, also indicate a strong sensitivity of the parallel performance to the load level of the nodes, in terms of the number of simultaneously used cores. This performance degradation is related to memory bottlenecks during the modal analysis required during each FE analysis.

A Comparative Study Between Light Extinction and Direct Sampling Methods for Measuring Volume Fractions of Twin-Hole Sprays Using Tomographic Reconstruction

  • Lee, Choong-Hoon
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.1986-1993
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    • 2003
  • The spatially resolved spray volume fractions from both line-of-sight data of direct measuring cells and a laser diffraction particle analyzer (LDPA) are tomographically reconstructed by the Convolution Fourier transformation, respectively. Asymmetric sprays generated from a twin-hole injector are tested with 12 equiangular projections of measurements. For each projection angle, a line-of-sight integrated injection rate was measured using a direct sampling method and also a liquid volume fraction from a set of line-of-sight Fraunhofer diffraction measurements was measured using a light extinction method. Interpolated data between the projection angles effectively increase the number of projections, significantly enhancing the signal-to-noise level in the reconstructed data. The reconstructed volume fractions from the direct sampling cells were used as reference data for evaluating the accuracy of the volume fractions from the LDPA.

THE AVERAGING VALUE OF A SAMPLING OF THE RIEMANN ZETA FUNCTION ON THE CRITICAL LINE USING POISSON DISTRIBUTION

  • Jo, Sihun
    • East Asian mathematical journal
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    • v.34 no.3
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    • pp.287-293
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    • 2018
  • We investigate the averaging value of a random sampling ${\zeta}(1/2+iX_t)$ of the Riemann zeta function on the critical line. Our result is that if $X_t$ is an increasing random sampling with Poisson distribution, then $${\mathbb{E}}{\zeta}(1/2+iX_t)=O({\sqrt{\;log\;t}}$$, for all sufficiently large t in ${\mathbb{R}}$.