• Journal of Korean Society of Steel Construction
• /
• v.15 no.4 s.65
• /
• pp.435-445
• /
• 2003

Tension member is one of the most important elements in tension structure. An economical and reliable measurement method of a member's tensile force has yet to be developed, however. Several conventional measurement methods have some disadvantages when used for long-term, on-site measurement. A new tension-force measurement device was proposed to resolve measuring problems. Its principle was to use the bending part of the device as an elastic spring. The lateral deformation of the bending part due to tensile force can be measured to monitor the tensile force. This device was inserted in the tension member like a turn-buckle. Lateral deformation may be measured in the field at any time for the purpose of maintaining structures. Finite element analysis was used to design the shape and parametric study. Six specimens were tested within the elastic range. The test result showed that the elastic behavior or the bending part was consistent with the analysis' results.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1324-1327
• /
• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network

• Journal of Environmental Impact Assessment
• /
• v.24 no.6
• /
• pp.607-618
• /
• 2015

Five years have passed since the first set of environmental samples was taken in 2011 to represent various ecosystems which would help future generations lead back to the past environment. Those samples have been preserved cryogenically in the National Environmental Specimen Bank(NESB) at the National Institute of Environmental Research. Even though there is a strict regulation (SOP, standard operating procedure) that rules over the whole sampling procedure to ensure each sample to represent the sampling area, it has not been put to the test for the validation. The question needs to be answered to clear any doubts on the representativeness and the quality of the samples. In order to address the question and ensure the sampling practice set in the SOP, many steps to the measurement of the sample, that is, from sampling in the field and the chemical analysis in the lab are broken down to evaluate the uncertainty at each level. Of the 8 species currently taken for the cryogenic preservation in the NESB, pine tree samples from two different sites were selected for this study. Duplicate samples were taken from each site according to the sampling protocol followed by the duplicate analyses which were carried out for each discrete sample. The uncertainties were evaluated by Robust ANOVA; two levels of uncertainty, one is the uncertainty from the sampling practice, and the other from the analytical process, were then compiled to give the measurement uncertainty on a measured concentration of the measurand. As a result, it was confirmed that it is the sampling practice not the analytical process that accounts for the most of the measurement uncertainty. Based on the top-down approach for the measurement uncertainty, the efficient way to ensure the representativeness of the sample was to increase the quantity of each discrete sample for the making of a composite sample, than to increase the number of the discrete samples across the site. Furthermore, the cost-effective approach to enhance the confidence level on the measurement can be expected from the efforts to lower the sampling uncertainty, not the analytical uncertainty. To test the representativeness of a composite sample of a sampling area, the variance within the site should be less than the difference from duplicate sampling. For that, a criterion, ${i.e.s^2}_{geochem}$(across the site variance) <${s^2}_{samp}$(variance at the sampling location) was proposed. In light of the criterion, the two representative samples for the two study areas passed the requirement. In contrast, whenever the variance of among the sampling locations (i.e. across the site) is larger than the sampling variance, more sampling increments need to be added within the sampling area until the requirement for the representativeness is achieved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.297-298
• /
• 2008

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.202-205
• /
• 1999

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.747-748
• /
• 2013

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2018.05a
• /
• pp.21-22
• /
• 2018

• Journal of Korean Society of Forest Science
• /
• v.101 no.3
• /
• pp.395-404
• /
• 2012

This study was conducted to develop site index equations and to estimate productive areas for major coniferous species in Korea such as Pinus densiflora Sieb. et. Zucc, Pinus densiflora for. erect, Larix leptolepis and Pinus koraiensis using environmental factors. Using the large data set from both a digital forest site map and a climatic map, a total of 43 environmental factors including 15 climatic variables were regressed on site index by tree species to develop site index equations. Six environmental factors by species were selected as independent variables in the final site index equations. The result showed that the coefficients of determination for site index equations by species were ranged from 0.36 to 0.56, which seem to be relatively low but good enough for the estimation of forest stand productivity. The site index equations developed in this study were also verified by three evaluation statistics such as the estimation bias of model, precision of model, and mean square error of measurement. According to the evaluation statistics, it was found that the site index equations by species fitted well to the test data sets with relatively low bias and variation. As a result, it was concluded that the site index equations by species were well capable of estimating site quality. Based on the site index equations, the productive areas by species for all forest areas were estimated by applying GIS technique to the digital forest site map and climate map. In addition, the distribution of productive areas by species was illustrated by using GIS technique.

• Journal of Advanced Navigation Technology
• /
• v.16 no.6
• /
• pp.935-943
• /
• 2012

In this paper a three step procedure was derived to select the GNSS network receiving site candidates for GNSS based infrastructure technology development and according to the proposed procedure the 4 site candidates was selected for final network configuration. In the first step, the site requirement was produced for GNSS based infrastructure technology development referring regulation of the international organizations related to permanent GNSS data receiving and the first candidates were selected using the proposed requirement. In the second step, the second candidates were selected among the first candidates by analyzing the visual measurement, environment test and so on. In the third step the final candidates were selected among the second candidates by analyzing sky clearance, radio frequency interference. Through above the three step procedure 16,7,4 candidates of site were selected sequentially and receiving station site could be effectively selected.

• Journal of Korean society of Dental Hygiene
• /
• v.16 no.2
• /
• pp.241-248
• /
• 2016

Objectives: The purpose of the study is to evaluate the dental website usability in Korea. The dental website included dental university hospital, network dental hospital and dental office. Methods: The study was carried out by three age groups including twenties, thirties, and forties. Each group consisted of ten customers and evaluated twelve websites of dental hospitals. Each was assigned to four hospitals and three tasks including easiness of online reservation, preventive information, and treatment information. They filled out the self-administered questionnaire. The questionnaire included the easiness of on-line reservation, satisfaction on the quality and quantity of preventive informations, satisfaction on the quality and quantity of treatment informations, predictiveness on the sub-menu, usefulness of site map, information on the main page of web site, usefulness of decision on visit to dentistry, and revisit intention. Results: The easiness of on-line reservation was the highest in the private dental office, and university dental hospital and network dental hospitals followed in conducting task(1). The anticipated value and measurement on the usefulness of web site were the lowest in network dental hospitals and the time interval between two values was 57 seconds. This discrepancy showed the largest difference. The satisfaction on treatment information in task(3) was higher than that of the satisfaction on preventive information in task (2). The revisit intention was the highest in dental university hospitals. Conclusions: This study showed the comparison in usefulness of web site of university dental hospitals, network dental hospitals and private dental office. The web site focused on the treatment information rather than preventive information. This study suggested that the most important function of dental web site would be the preventive information that was mainly operated by the role of dental hygienists rather than treatment information in the future.