• Title/Summary/Keyword: Reference set

Search Result 1,199, Processing Time 0.026 seconds

Analysis of position accuracy of ground/underground facilities (지상ㆍ지하시설물의 위치정보 신뢰성 분석)

  • 손홍규;한춘득;김기홍;손덕재
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
    • /
    • 2004.11a
    • /
    • pp.405-410
    • /
    • 2004
  • In mid-90's, the Korean government introduced the GIS(Geographic Information System) to digitalize every topography of national land and thereby, index locations and attributes of various urban facilities to construct a system whereby every information could be managed and operated in an integrated way, but the reliability of such geographic information has yet to be tested, much less its modification, complementation and maintenance. Under such circumstances, this study was aimed at constructing a reference point infrastructure for Seoul and Kyonggi area and comparing the data obtained from the GPS operation and various facility location data with the existing GIS data to address the problems of GIS operation and suggest their solutions. As a result of calculating the GPS reference point data and analyzing the deviations of the unknown point data in comparison with the fixed point ones, it was found that the horizontal location values were reliable within +/- 5cm, but that the above-sea level values varied as much as 1.4m depending on the deployment of pre-set fixed points determined by the direct level gauging. In addition, as a result of directly surveying major facilities around the roads based on the coordinates of the urban reference points networked with such a reference point system to check their conformity to existing data, it was confirmed that the difference was as wide as 2m. Such differences may be attributable to the fact that the data with their geographic information not confirmed are used as basic data for GIS. Hence, this study suggests the ways to set the absolute geographic data based on reference points and test the reliability of existing data and thereby, suggests a methods to solve the problems.

  • PDF

Developing Model of Drought Climate Scenarios for Agricultural Drought Mitigation (농업가뭄대응을 위한 가뭄기상시나리오 모델 개발 및 적용)

  • Yoo, Seung-Hwan;Choi, Jin-Yong;Nam, Won-Ho;Kim, Tae-Gon;Go, Gwang-Don
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.54 no.2
    • /
    • pp.67-75
    • /
    • 2012
  • Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Evaluation and forecast the status of drought for the present and future utilizing the meteorological scenario for agricultural drought can be useful to set a plan for agricultural drought mitigation in agriculture water resource management. In this study, drought climate scenario model on the basis of historical drought records for preparing agricultural drought mitigation was developed. To consider dependency and correlation between various climate variables, this model was utilized the historical climate pattern using reference year setting of four drought levels. The reference year for drought level was determined based on the frequency analysis result of monthly effective rainfall. On the basis of this model, drought climate scenarios at Suwon and Icheon station were set up and these scenarios were applied on the water balance simulation of reservoir water storage for Madun reservoir as well as the soil moisture model for Gosam reservoir watershed. The results showed that drought climate scenarios in this study could be more useful for long-term forecast of longer than 2~3 months period rather than short-term forecast of below one month.

Intergalactic Magnetic Field and Arrival Direction of Ultra-High-Energy Iron Nuclei

  • Ryu, Dongsu;Kang, Hyesung;Das, Santabrata
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.37 no.2
    • /
    • pp.78.2-78.2
    • /
    • 2012
  • We have studied how the intergalactic magnetic field (IGMF) affects the propagation of super-GZK iron nuclei that originate from extragalactic sources within the local GZK sphere. Toward this end, we set up hypothetical sources of ultra-high-energy cosmic-rays (UHECRs), virtual observers, and the magnetized cosmic web in a model universe constructed from cosmological structure formation simulations. We then arranged a set of reference objects at high density region to represent astronomical objects formed in the large scale structure (LSS). With our model IGMF, the paths of UHE iron nuclei are deflected on average by about 70 degrees, which might indicate a nearly isotropic distribution of arrival directions. However, the separation angle between the arrival directions and the nearest reference object on the LSS is only ~6 degrees, which is twice the mean distance to the nearest neighbors among the reference objects. This means that the positional correlation of observed UHE iron events with their true sources would be erased by the IGMF, but the correlation with the LSS itself is to be sustained. We discuss implications of our findings for correlations studies of real UHECR events.

  • PDF

3D Segmentation of a Diagnostic Object in Ultrasound Images Using LoG Operator (초음파 영상에서 LoG 연산자를 이용한 진단 객체의 3차원 분할)

  • 정말남;곽종인;김상현;김남철
    • Journal of Biomedical Engineering Research
    • /
    • v.24 no.4
    • /
    • pp.247-257
    • /
    • 2003
  • This paper proposes a three-dimensional (3D) segmentation algorithm for extracting a diagnostic object from ultrasound images by using a LoG operator In the proposed algorithm, 2D cutting planes are first obtained by the equiangular revolution of a cross sectional Plane on a reference axis for a 3D volume data. In each 2D ultrasound image. a region of interest (ROI) box that is included tightly in a diagnostic object of interest is set. Inside the ROI box, a LoG operator, where the value of $\sigma$ is adaptively selected by the distance between reference points and the variance of the 2D image, extracts edges in the 2D image. In Post processing. regions of the edge image are found out by region filling, small regions in the region filled image are removed. and the contour image of the object is obtained by morphological opening finally. a 3D volume of the diagnostic object is rendered from the set of contour images obtained by post-processing. Experimental results for a tumor and gall bladder volume data show that the proposed method yields on average two times reduction in error rate over Krivanek's method when the results obtained manually are used as a reference data.

A Study on Suitability of the USN-Based Portable Reference Equipment for ITS Systems Performance Evaluation (USN-기반 이동식 기준장비의 ITS 장비 성능평가 적합성에 관한 연구)

  • Lee, Sang Hyup;Ma, Chang Young
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.31 no.6D
    • /
    • pp.765-769
    • /
    • 2011
  • The existing portable reference equipment for ITS systems performance evaluation has several limitations. First, it is difficult to set up and operate the equipment in the road section with the shoulder width equal to or smaller than 1.5m. Secondly, the crash with a car could lead to severe accident since it is big and heavy. Lastly, it cannot collect data from multiple lanes at a time. In this research the characteristics of the USN-based portable reference equipment developed to overcome shortcomings of the existing portable reference equipment were analyzed qualitatively and its performance level was evaluated through the field test. Consequently, the USN-based portable reference equipment turned out to overcome the operational shortcomings and satisfy the performance level required for the portable reference equipment.

Establishment of Total Sugar Reference Value for Koreans (한국인 총당류 섭취기준 설정)

  • Cho, Sung-Hee;Chung, Chin-Eun;Kim, Sun-Hee;Chung, Hye-Kyung
    • Journal of Nutrition and Health
    • /
    • v.40 no.sup
    • /
    • pp.3-8
    • /
    • 2007
  • Sugars are a ubiquitous component of our food supply and are consumed as a naturally occurring component of many foods and as additions to foods during processing, preparation, or at the table. Most fruits and dairy products are high in sugars and thus naturally occurring sugars are consumed as part of a healthy diet. Some countries developed recommended daily intake figures(daily values : DVs or guideline daily amounts: GDA) for nutrients, and some countries, but not most have developed DV/GDA for total sugars. Dietary Reference Intakes for Koreans established by the Korean Nutrition Society in 2005, did not include the reference values for total sugar or added sugar. The committee on Dietary Reference Intakes for sugar was constituted in 2006 and discussed whether to special added sugars or total sugar. Although added sugars are not chemically or physiologically different from naturally occurring sugars, many foods and beverages that are major sources of added sugars have lower micronutrient densities compared with foods and beverages that are major sources of naturally occuring sugars. But it was so hard to calculate a dietary intake of added sugar for Korean people, because there was insufficient information about contents of added sugar during processing or preparation of Korean food. Currently Korean or US food labels contain information on total sugars per serving but do not distinguish between sugars naturally present in food and added sugars. Therefore the committee decided to set the reference value for total sugar for Koreans. According to the recommended diet pattern for Koreans suggested by the Korean Nutrition Society, estimated sugar intake from the sugar containing food based on 2,000 kilocalories is 67 g or 13% of total energy. Based on the data available on risk of obesity, hypertension, hyperlipidemia, insulin resistance, and metabolic syndrome from the analysis of Korean NHANES, it was insufficient evidence to set a UL for total sugar, but tended to increase serum LDL cholesterol and obesity at over 20-25% of energy from total sugar when consumed with high carbohydrates. Therefore the committee on Dietary Reference Intakes for sugar set the Acceptable Macronutrient Distribution Range for total sugar as 10-20% of total energy intake.

Compensation of Source Voltage Unbalance and Current Harmonics in Series Active and Shunt Passive Power Filters

  • Lee G-Myoung;Lee Dong-Choon
    • Proceedings of the KIPE Conference
    • /
    • 2001.10a
    • /
    • pp.586-590
    • /
    • 2001
  • In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for hybrid active power filters is proposed, where no low/high-pass filters are used in compensation voltage composition. The phase angle and compensation voltages for source harmonic current and unbalanced voltage components are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. Since a balanced set of the source voltage obtained by scaling the positive sequence components is used as reference values for source current and load voltage, it is possible to eliminate the necessity of low/high-pass filters in the reference generation. Therefore the control algorithm is much simpler and gives more stable performance than the conventional method. In addition, the source harmonic current is eliminated by compensating for the harmonic voltage of the load side added to feedback control of the fundamental component.

  • PDF

Deformable image registration in radiation therapy

  • Oh, Seungjong;Kim, Siyong
    • Radiation Oncology Journal
    • /
    • v.35 no.2
    • /
    • pp.101-111
    • /
    • 2017
  • The number of imaging data sets has significantly increased during radiation treatment after introducing a diverse range of advanced techniques into the field of radiation oncology. As a consequence, there have been many studies proposing meaningful applications of imaging data set use. These applications commonly require a method to align the data sets at a reference. Deformable image registration (DIR) is a process which satisfies this requirement by locally registering image data sets into a reference image set. DIR identifies the spatial correspondence in order to minimize the differences between two or among multiple sets of images. This article describes clinical applications, validation, and algorithms of DIR techniques. Applications of DIR in radiation treatment include dose accumulation, mathematical modeling, automatic segmentation, and functional imaging. Validation methods discussed are based on anatomical landmarks, physical phantoms, digital phantoms, and per application purpose. DIR algorithms are also briefly reviewed with respect to two algorithmic components: similarity index and deformation models.

Comparative studies of density functionals in modelling hydrogen bonding energetics of acrylamide dimers

  • Lin, Yi-De;Wang, Yi-Siang;Chao, Sheng D.
    • Coupled systems mechanics
    • /
    • v.6 no.3
    • /
    • pp.369-376
    • /
    • 2017
  • Intermolecular interaction energies and conformer geometries of the hydrogen bonded acrylamide dimers have been studied by using the second-order Møller-Plesset (MP2) perturbation theory and the density functional theory (DFT) with 17 density functionals. Dunning's correlation consistent basis sets (up to aug-cc-pVTZ) have been used to study the basis set effects. The DFT calculated interaction energies are compared to the reference energy data calculated by the MP2 method and the coupled cluster method at the complete basis set (CCSD(T)/CBS) limit in order to determine the relative performance of the studied density functionals. Overall, dispersion-energy-corrected density functionals outperform uncorrected ones. The ${\omega}B97XD$ density functional is particularly effective in terms of both accuracy and computational cost in estimating the reference energy values using small basis sets and is highly recommended for similar calculations for larger systems.

Design of Video Quality Assurance and Integrated Quality Management System using No Reference QoE (비 참조 QoE를 이용한 영상품질 측정 및 통합품질 관리 시스템의 설계)

  • Kim, Sang-Soo;Park, Dong-Soo
    • The Journal of Information Technology
    • /
    • v.12 no.3
    • /
    • pp.49-57
    • /
    • 2009
  • This Paper provides perceptual metrics for video quality based on properties of human visual system, and audio quality based on human audition. All metrics work without reference signals, allowing non-intrusive, in-service measurements. A simple and easy-to-learn user interface displays the metrics and saves them in popular file formats like CSV. In this paper, proposed method was able to various and corrective measurement for the multimedia service video quality. As that it was able to application to set up service guide line and the methode of measurement and system for the set up standardization of the high quality video service.

  • PDF