• Korean Journal of Remote Sensing
• /
• v.26 no.6
• /
• pp.653-664
• /
• 2010

The land surface reflectance is a key parameter influencing the climate near the surface. Therefore, it must be determined with sufficient accuracy for climate change research. In particular, the characteristics of the bidirectional reflectance distribution function (BRDF) when using earth observation system (EOS) are important for normalizing the reflected solar radiation from the earth's surface. Also, wide swath satellites like SPOT/VGT (VEGETATION) permit sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning. This gives a difficulty to BRDF model based reflectance normalization of high resolution satellites. The principal objective of the study is to add BRDF modeling of high resolution satellites and to supply insufficient angular sampling through identifying BRDF components from SPOT/VGT. This study is performed as the preliminary data for apply to high-resolution satellite. The study provides surface parameters by eliminating BRD effect when calculated biophysical index of plant by BRDF model. We use semi-empirical BRDF model to identify the BRD components. This study uses SPOT/VGT satellite data acquired in the S1 (daily) data. Modeled reflectance values show a good agreement with measured reflectance values from SPOT satellite. This study analyzes BRD effect components by using the NDVI(Normalized Difference Vegetation Index) and the angle components such as solar zenith angle, satellite zenith angle and relative azimuth angle. Geometric scattering kernel mainly depends on the azimuth angle variation and volumetric scattering kernel is less dependent on the azimuth angle variation. Also, forest from land cover shows the wider distribution of value than cropland, overall tendency is similar. Forest shows relatively larger value of geometric term ($K_1{\cdot}f_1$) than cropland, When performed comparison between cropland and forest. Angle and NDVI value are closely related.

• Smart Structures and Systems
• /
• v.6 no.5_6
• /
• pp.731-748
• /
• 2010

Impact detection and health monitoring are very important tasks for civil infrastructures, such as bridges. Piezoceramic based transducers are widely researched for these tasks due to the piezoceramic material's inherent advantages of dual sensing and actuation ability, which enables the active sensing method for structural health monitoring with a network of piezoceramic transducers. Wireless sensor networks, which are easy for deployment, have great potential in health monitoring systems for large civil infrastructures to identify early-age damages. However, most commercial wireless sensor networks are general purpose and may not be optimized for a network of piezoceramic based transducers. Wireless networks of piezoceramic transducers for active sensing have special requirements, such as relatively high sampling rate (at a few-thousand Hz), incorporation of an amplifier for the piezoceramic element for actuation, and low energy consumption for actuation. In this paper, a wireless network is specially designed for piezoceramic transducers to implement impact detection and active sensing for structural health monitoring. A power efficient embedded system is designed to form the wireless sensor network that is capable of high sampling rate. A 32 bit RISC wireless microcontroller is chosen as the main processor. Detailed design of the hardware system and software system of the wireless sensor network is presented in this paper. To verify the functionality of the wireless sensor network, it is deployed on a two-story concrete frame with embedded piezoceramic transducers, and the active sensing property of piezoceramic material is used to detect the damage in the structure. Experimental results show that the wireless sensor network can effectively implement active sensing and impact detection with high sampling rate while maintaining low power consumption by performing offline data processing and minimizing wireless communication.

• Journal of Climate Change Research
• /
• v.6 no.1
• /
• pp.33-40
• /
• 2015

Forests are to be recognized as an important carbon sink under the UNFCCC that consist of above- and below-biomass, dead organic matter (DOM) such as dead wood and litter, and soil organic matter (SOM). In order to asses for DOM and SOM, however, it is relevant to land-use change matrices over last 20 years for each land-use category. In this study, a land-use change matrix was produced and its uncertainty was assessed using a point sampling technique with permanent sample plots in national forest inventory at Chungbuk province. With point sampling estimated areas at 2012 year for each land-use category were significantly similar to the true areas by given six land-use categories. Relative standard error in terms of uncertainty of land-use change among land-use categories ranged in 4.3~44.4%, excluding the other land. Forest and cropland covered relatively large areas showed lower uncertainty compared to the other land-use categories. This result showed that selected permanent samples in the NFI are able to support for producing land-use change matrix at a national or province level. If the $6^{th}$ NFI data are fully collected, the uncertainty of estimated area should be improved.

• Journal of the Korean housing association
• /
• v.16 no.2
• /
• pp.99-105
• /
• 2005

Due to the vast increase in the elderly population and the changes in traditional filial duties, the importance of the elderly living arrangement is being greatly emphasized. The purpose of this study was to analyse the determinant factor of intention to move into senior congregate housing. The survey was conducted among middle-aged people in their fifties, who lived in Seoul, using the systematic random sampling method. The final sample included 498 respondents. The results were as follows. 1) It was revealed that many respondents thought positively about senior congregate housing. Both of having children and income were proved as an important variables which had an impact factor to move into senior congregate housing. 2) It was found that residential environment was the more important factor than housing level itself or personal social environment.

• Korean Journal of Human Ecology
• /
• v.4 no.2
• /
• pp.123-140
• /
• 2001

The purpose of this study is to find the suitable suit design of mid-aged men by examining visual effects in Physical and Psychological side aspects. I used convenience sampling by considering sex and age distribution. These methods were used to analyze data that were frequency analysis, variate analysis, centesimal scale, primary factor analysis, three primary variate analysis, duality variate analysis, equation variate analysis and Cronbach's multiplex range verification 1. Image perception of men's suit was analyzed with arrangement, numbers of button, pattern and the shape of one's body and was divided into charming, youthfulness, modernism. affection and manly. 2. 1) There are partly resemblance difference in physical visual effect by the shape of body and suit design. 2) There are partly resemblance differences in psychological visual effect by one's shape and suit design. In conclusion arrangement, number of button and Pattern are very important to give an effect on whole visual effect man's suit. Also, these were felt differently in each types of body Therefore it is confirmed that the type of body is important fluent to make people perceive.

• The Journal of Information Systems
• /
• v.12 no.2
• /
• pp.41-56
• /
• 2003

The objective of this study is to explore the effects of e-teaming users' self-efficacy and perceived service quality for e-teaming staffs such as instructors or teaching assistants on two main perceptions for e-learning systems in a view of information technology - perceived ease of use and perceived usefulness which have been considered as important antecedents for acceptance of information technology so called in Technology Acceptance Model. For this purpose, we suggest a research model and test it empirically by sampling in students of virtual universities. In result, all hypotheses except the relationship between academic self-efficacy and perceived usefulness are accepted. This result implies that self-efficacy for computers and service quality for staffs such as instructors or teaching assistants should be considered as important ones for success of e-learning systems in addition to those related with information technology.

• Journal of the Korean Society of Safety
• /
• v.29 no.3
• /
• pp.136-142
• /
• 2014

Recently a new version of PRO-LOCA program was released. Using the program, failure probability of pipes can be evaluated considering fatigue and/or stress corrosion crack growth and the effects of various parameters on the integrity of pipes in nuclear power plants can be evaluated quantitatively. The analysis results can be used to establish an inspection plan and to examine the effects of important parameters in a maintenance plan. In this study, sensitivity analyses were performed using the program for several important parameters including sampling method, initial crack size, number of initial fabrication flaws, operation temperature, inspection interval, operation temperature and nominal applied bending stress. The effect of parameters on the leak and rupture probability of pipes was evaluated due to fatigue or stress corrosion crack growth.

• Geosciences Journal
• /
• v.22 no.6
• /
• pp.891-902
• /
• 2018

Techniques for more reliable detection of 3D subsurface flow paths are highly important for most water-related geotechnical projects. In this case study, a magnetometric resistivity method with a new approach and state-of-the-art technology ("Willowstick survey") was applied to the testbed dam (YD dam) site, and its applicability was validated by geotechnical investigation techniques including borehole drilling and sampling, Lugeon test, flow direction and velocity test, and seismic tomography. In addition to the magnetometric survey, a 3D electrical resistivity survey was performed independently and the results were compared and discussed. The electrical resistivity survey was effective in detecting groundwater levels, but it was limited in mapping leakage paths. On the other hand, the Willowstick magnetometric survey effectively detected geologic weaknesses (e.g., fault fracture) and potential leakage paths of the dam site foundation rocks. The results of this research are expected to be effective for water infrastructures where leakage is an important issue.

• Journal of Environmental Science International
• /
• v.6 no.6
• /
• pp.563-578
• /
• 1997

The purpose of this study is to suggest the estimation model of' amenity environment' by Perceived Envionmental Quality Index(PEQI) model. A questionnaire survey was carried out for 연e study area of Taegu-Kyungbuk region. Sampling size was 838(427 of Taegu and 411 of Kyungbuk residents by stratified sampling of each region's(7 Gu for Tae-gu, 7 Cities 61 Gun far Kyungbuk) population. The survey was done during Sep. to Nov, of 1996. The suggested model was composed of four estimation categories and 16 Indicators. The four categories were 'Cleanness 61 Quietness', 'Naturalness & Harmony', 'Beauty 61 Comfort' and 'Environmental Conservation Efforts'. And each category has several individual Indicators. The weighted means of satisfaction were different by each region. Suseong-gu, Dalseogu, Joong-gu(Taegu), Bumcheon, Andong, and Cheondo(Kyungbuk) showed high enoronmental satisfaction, but Dong-gu. Seo-gu(taegu), Youngcheon, and Pohang(Kyungbuk) showed lower environmental satisfaction. By Analytic Hierarchy Process(AHP) of weighting values for each categorirs, 'Enoronmental Conservation Efforts' was estimated as the most Important(value of 0.367), and 'Naturalness 61 Harmony'(0. 242),'Clenness & guletness'(0.225), and 'Beauty & Comfort'(0.166) were Important respectively. Total PEQI's were estimated as 48.0 for Taegu, and 53.3 for Kyungbuk. PEQI's for each regions were between 46.2(Dong-gu) and 59.9(Kimcheon). The validity of the suggested model was verined by factor analysis. The four factors were identnied as the same categories and indicators. Finally, The LISREL+7 model was suggested as estimauon model of 'Amenity Environment' for Taegu-Kyungbuk region.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.3
• /
• pp.219-236
• /
• 2009

Particle-phase organic tracers (molecular markers) have been shown to be an effective method to assess and quantify the impact of sources of carbonaceous aerosols. These molecular markers have been used in chemical mass balance (CMB) models to apportion primary sources of organic aerosols in regions where the major organic aerosol source categories have been identified. As in the case of all CMB models, all important sources of the tracer compounds must be included in a Molecular Marker CMB (MM-CMB) model or the MMCMB model can be subject to biases. To this end, the application of the MM-CMB models to locations where reasonably accurate emissions inventory of organic aerosols are not available, should be performed with extreme caution. Of great concern is the potential presence of industrial point sources that emit carbonaceous aerosols and have not been well characterized or inventoried. The current study demonstrates that emissions from industrial point sources in the St. Louis, Missouri area can greatly bias molecular marker CMB models if their emissions are not correctly addressed. At a sampling site in the greater St. Louis Area, carbonaceous aerosols from industrial point sources were found to be important source of carbonaceous aerosols during specific time periods in addition to common urban sources (i.e. mobile sources, wood burning, and road dust). Since source profiles for these industrial sources have not been properly characterized, method to identify time periods when point sources are impacting a sampling site, needs to avoid obtaining biases source apportionment results. The use of real time air pollution measurements, along with molecular marker measurements, as a screening tool to identify when point sources are impacting a receptor site is presented.