• Title/Summary/Keyword: Survey control

Search Result 4,244, Processing Time 0.036 seconds

Analysis of the GPS-derived Control Point Errors for Quality Assurance of 3D Digital Maps (3차원 수치지도 정확도 검증을 위한 GPS 기반 기준점 오차의 영향 분석)

  • Bae, Tae-Suk;Lee, Dong-Cheon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.28 no.1
    • /
    • pp.153-160
    • /
    • 2010
  • It is necessary to determine accurate 3-dimensional coordinates of the building corner points that could be control or check points in order to verify the accuracy of 3D digital maps in the near future. The usual process of obtaining the coordinates of the building corner points is to set up the ground control points with a GPS and then to practice terrestrial survey such as distance or angle measurements. However, since an error in the ground control points can be propagated through the terrestrial survey into the final coordinates of the buildings, accurately should be considered as much as possible. The actual effect of the GPS-derived ground control point error on the estimates of the unknowns through the terrestrial survey is mathematically analyzed, and the simulation data is tested numerically. The error of the ground control points is tested in the cases of 1-4 cm for the horizontal components and 2-8 cm for the vertical component. The vertical component error is assigned twice the horizontal ones because of the characteristics of the GPS survey. The distance measurement is assumed for convenience and the precision of the estimated coordinates of the building corner points is almost linearly increased according to the errors of the ground control points. In addition, the final estimates themselves can vary by the simulated random errors depending on the precision of the survey instrument, but the precision of the estimates is almost independent of survey accuracy.

Development of a Sampling Strategy and Sample Size Calculation to Estimate the Distribution of Mammographic Breast Density in Korean Women

  • Jun, Jae Kwan;Kim, Mi Jin;Choi, Kui Son;Suh, Mina;Jung, Kyu-Won
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.9
    • /
    • pp.4661-4664
    • /
    • 2012
  • Mammographic breast density is a known risk factor for breast cancer. To conduct a survey to estimate the distribution of mammographic breast density in Korean women, appropriate sampling strategies for representative and efficient sampling design were evaluated through simulation. Using the target population from the National Cancer Screening Programme (NCSP) for breast cancer in 2009, we verified the distribution estimate by repeating the simulation 1,000 times using stratified random sampling to investigate the distribution of breast density of 1,340,362 women. According to the simulation results, using a sampling design stratifying the nation into three groups (metropolitan, urban, and rural), with a total sample size of 4,000, we estimated the distribution of breast density in Korean women at a level of 0.01% tolerance. Based on the results of our study, a nationwide survey for estimating the distribution of mammographic breast density among Korean women can be conducted efficiently.

A Study on the Development of Information System for the Ship Survey to Support Port State Control (항만국 통제 지원 선박검사 정보시스템 개발에 관한 연구)

  • 박주용;강병윤;이경철
    • Journal of Ocean Engineering and Technology
    • /
    • v.14 no.3
    • /
    • pp.100-105
    • /
    • 2000
  • Port State Control (PSC) is the inspection of foreign ships in national ports for the purpose of verifying that the condition of the ships and its equipments comply with the requirement of international conventions and the ship is manned and operated in compliance with applicable international laws. On the other hand, check items in PSC are nearly similar to periodical survey of Classification Societies, because they have the same background regarding safety and maritime pollution prevention. The purpose of this study is to develope computer-aided information system for ship inspection item which is useful for effective implementation of Port State Control. For this work, the status of PSC is reviewed, and the related scheme of ship survey system in Classification Societies is investigated. On these bases, a computer software integrated database system and object-oriented technique is developed. The developed system is expected helpful to establish and maintain an effective system of Port State Control.

  • PDF

Cancer Screening in Korea, 2012: Results from the Korean National Cancer Screening Survey

  • Suh, Mina;Choi, Kui Son;Lee, Yoon Young;Park, Boyoung;Jun, Jae Kwan
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.11
    • /
    • pp.6459-6463
    • /
    • 2013
  • We investigated the cancer screening rates for five types of cancer (stomach, liver, colorectal, breast, and cervix uteri) using data from the Korean National Cancer Screening Survey (KNCSS), which is a nationwide, annual cross-sectional survey. The eligible study population included cancer-free men 40 years of age and older and women 30 years of age and older. The lifetime screening rate and screening rate with recommendation were calculated. The lifetime screening rates for gastric, liver, colorectal, breast, and cervical cancers were 77.9%, 69.9%, 65.8%, 82.9%, and 77.1%, respectively. The screening rates with recommendation were 70.9%, 21.5%, 44.7%, 70.9%, and 67.9%, respectively. The most common reason for all types of cancer was "no symptoms", followed by "lack of time" and "fear of the examination procedure". Efforts to facilitate participation in liver and colorectal cancer screening among Korean men and women are needed.

A Study on the Development of Information System for the Ship Survey to Support Port State Control (항만국 통제 지원 선박검사 정보시스템 개발에 관한 연구)

  • 박주용;강병윤;이경철;정진욱
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2000.10a
    • /
    • pp.165-170
    • /
    • 2000
  • Port State Control (PSC) is the inspection of foreign ships in national ports for the purpose of verifying th\ulcorner the condition of the ships and its equipments comply with the requirement of international conventions and the ship is manned and operated in compliance with applicable international laws. On the other hand, check items in PSC are nearly similar to periodical survey of Classification Societies, because they have the same background regarding safety and maritime pollution prevention. The purpose of this study is to develope computer-aided information systems for ship inspection item which is useful for effective implementation of Port State Control. For this work, the status of PSC is reviewed, and the related scheme of ship survey system in Classification Societies is investigated. On these bases, a computer software integrated database system and object-oriented technique is developed. The developed system is expected helpful to establish and maintain an effective system of Port State Control.

  • PDF

Quality Test and Control of Kinematic DGPS Survey Results

  • Lim, Sam-Sung
    • Journal of Korean Society for Geospatial Information Science
    • /
    • v.10 no.5 s.23
    • /
    • pp.75-80
    • /
    • 2002
  • Depending upon geographical features and surrounding errors in the survey field, inaccurate positioning is inevitable in a kinematic DGPs survey. Therefore, a data inaccuracy detection algorithm and an interpolation algorithm are essential to meet the requirement of a digital map. In this study, GPS characteristics are taken into account to develop the data inaccuracy detection algorithm. Then, the data interpolation algothim is obtained, based on the feature type of the survey. A digital map for 20km of a rural highway is produced by the kinematic DGPS survey and the features of interests are lines associated with the road. Since the vertical variation of GPS data is relatively higher, the trimmed mean of vertical variation is used as criteria of the inaccuracy detection. Four cases of 0.5%, 1%, 2.5% and 5% trimmings have been experimented. Criteria of four cases are 69cm, 65cm, 61cm and 42cm, respectively. For the feature of a curved line, cublic spine interpolation is used to correct the inaccurate data. When the feature is more or less a straight line, the interpolation has been done by a linear polynomial. Difference between the actual distance and the interpolated distance are few centimeters in RMS.

  • PDF

Analysis of Network-RTK(VRS) Positioning Accuracy for Surveying Public Control Point (공공기준점 측량에 적용을 위한 VRS(가상기준점) 방식의 Network-RTK 정확도 분석)

  • Han, Joong-Hee;Kwon, Jay-Hyoun;Hong, Chang-Ki
    • Journal of Korean Society for Geospatial Information Science
    • /
    • v.18 no.2
    • /
    • pp.13-20
    • /
    • 2010
  • Currently, NGII(National Geographic Information Institute) provides VRS(Virtual Reference System) service using 44 CORS(Continuously Operating Reference Stations). Since the VRS provides high-precision coordinate in a short time, the users and applications are expected to be rapidly increasing. The accuracy analysis on the VRS service, however, was not sufficiently performed yet. Therefore, in this study, the VRS data is acquired from various circumstances and its accuracy is analyzed. According to analysis, it was concluded that the VRS could be applied to public control point survey. Furthermore, it was found that the PQ(Position Quality) which represents variance of estimated coordinates rather than GDOP(Geometric Dilution of Precision) is more relevant as a factor to determine the accuracy of coordinates. Based on the analysis of data from four manufacturers (TRIMBLE, MAGELLAN, LECIA, TOPCON), it was confirmed that the standard deviations better than 3cm. Therefore, VRS Survey apply to public control point survey.

Predictors of Tobacco-Control Activities of Community Health Practitioners: Report from a National Survey

  • Kim Jin-Sun;Song Mee-Suk;Oh Hyun-Ei
    • Journal of Korean Academy of Nursing
    • /
    • v.34 no.8
    • /
    • pp.1443-1450
    • /
    • 2004
  • The involvement of health-care professionals in tobacco-control activities is essential to prevent smoking-related morbidity and mortality. The purposes of this predictive correlational study were to examine tobacco-control activities and to identify the predictors of such activities of community health practitioners (CHPs). Of the 1,813 members of the Korean Association of CHP, 1,247 participated in this study. A mailed survey was conducted to collect data. The majority of CHPs supported tobacco-control policies and recognized tobacco-control activities as an important role for them. Only $44.3\%$ of CHPs were confident in their knowledge and skills regarding tobacco-control activities, and only $30.8\%$ had received professional tobacco-control education. While the majority of the CHPs 'asked, advised, and assessed' their clients, only a small number 'assisted or arranged'. The tobacco-control activities of CHPs were predicted by their attitude toward it, age, experience of tobacco-control education, educational level, and general perception of the risk of smoking; these variables accounted $13.5\%$ of variance in the tobacco-control activities of CHPs. These findings provide the basis for developing a continuing education program for CHPs. CHPs should be encouraged to integrate tobacco-control activities into their routine practice, and CHP education programs should be adjusted to increase the time spent on the tobacco-control intervention techniques.

The Vegetation Health Assessment in Riparian Vegetation of Lake Reservoirs (저수지 수변 식생 건강성 평가)

  • Kim, Hyoungdae;Koo, Bonhak
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.19 no.6
    • /
    • pp.111-121
    • /
    • 2016
  • This study was carried out to assess the riparian vegetation health in the fluctuation area and vicinity of reservoirs. The results of this study could be a basic data to improve the ecological function and establish green-network of waterside ecosystem. The study site is Daecheong lake reservoirs which the representative landscape of Geum river and with great number of visitors near metropolitan city. The 6 survey plots of 2 survey area were selected, survey area 1 had 4 survey plots and survey area 2 had 2 survey plots, and to compare the study results 4 control plots were selected in Gyeongcheon reservoir. The main dominant specie of survey sites was Salix koreensis in tree and subtree layer, were Salix koreensis and Salix glandulosa. in shrub layer. 2 survey plots of Samjeongdong and Kyeongcheon reservoir were assessed as 'Good', 2 survey plots of chudong were assessed as 'Fair' in vegetation health assessment. In the fluctuation area from flood water level to low water level, 58 populations of Salix koreensis were found in survey sites and Salix koreensis, Salix glandulosa and Acer tataricum subsp. ginale were found in control sites. The most adequate species at the condition affected by inundation impacts would be Salix koreensis and Salix glandulosa was more healthy at the area less affected by inundation. This study was carried out the vegetation health assessment on Daecheong reservoir which has been advanced natural succession for more than 30 years after the construction. Further, it should carry continuously out the research on the planting model of the waterside ecosystem for ecological restoration.