• Korean Journal of Remote Sensing
• /
• v.39 no.2
• /
• pp.233-246
• /
• 2023

In terms of understanding the water cycle and efficient water resource management, the importance of soil moisture has been highlighted. However, in Korea, the lack of qualified in-situ soil moisture data results in very limited utility. Even if satellite-based data are applied, the absence of ground reference data makes objective evaluation and correction difficult. The cosmic-ray neutron probe (CRNP) can play a key role in producing data for satellite data calibration. The installation of CRNP is non-invasive, minimizing damage to the soil and vegetation environment, and has the advantage of having a spatial representative for the intermediate scale. These characteristics are advantageous to establish an observation network in Korea which has lots of mountainous areas with dense vegetation. Therefore, this study was conducted to evaluate the applicability of the CRNP soil moisture observatory in Korea as part of the establishment of a Korean cOsmic-ray Soil Moisture Observing System (KOSMOS). The CRNP observation station was installed with the Gunup-ri observation station, considering the ease of securing power and installation sites and the efficient use of other hydro-meteorological factors. In order to evaluate the CRNP soil moisture data, 12 additional in-situ soil moisture sensors were installed, and spatial representativeness was evaluated through a temporal stability analysis. The neutrons generated by CRNP were found to be about 1,087 counts per hour on average, which was lower than that of the Solmacheon observation station, indicating that the Hongcheon observation station has a more humid environment. Soil moisture was estimated through neutron correction and early-stage calibration of the observed neutron data. The CRNP soil moisture data showed a high correlation with r=0.82 and high accuracy with root mean square error=0.02 m³/m³ in validation with in-situ data, even in a short calibration period. It is expected that higher quality soil moisture data production with greater accuracy will be possible after recalibration with the accumulation of annual data reflecting seasonal patterns. These results, together with previous studies that verified the excellence of CRNP soil moisture data, suggest that high-quality soil moisture data can be produced when constructing KOSMOS.

• Tunnel and Underground Space
• /
• v.13 no.5
• /
• pp.344-352
• /
• 2003

The procedures to correct sampling biases for discontinuity data obtained from 1D survey line(borehole or scanline) is addressed. The Probability of intersection between the survey line and a circular discontinuity is considered, and a correction far orientation bias is developed assuming discontinuities as equivalent circular disks. The correction incorporates the effect of the angle between the direction of survey line and each discontinuity plane belonging to the discontinuity cluster, size of each discontinuity and length of the survey line. A procedure is provided to estimate unbiased discontinuity spacing parameters using the discontinuity spacing data based on the measurements carried out on a finite length of the survey line.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.6
• /
• pp.1155-1167
• /
• 2009

We made a new sample design for life and consciousness survey of Kyungpook people in 2007. We used the 10% sample survey data of 2005 population and housing census as a survey population. After stratification, we allocate proportionally samples within strata after examining various characteristics in previous survey, which includes economic activity state, an income level per year, and housing possession. And we calculated weight in a new sample design and derived estimators and a formula of standard error using the weights.

• Journal of Korean Society of Rural Planning
• /
• v.19 no.2
• /
• pp.51-61
• /
• 2013

The purpose of this study is to conduct an analysis of rural village's community status and consciousness through a questionnaire survey of community leaders and members. Nine types of rural village communities were selected in Korea through a pre-survey of amenity resources data from the Rural Development Administration. Survey items that could determine characteristics of rural village communities were derived from a literature survey of rural village community systems. A questionnaire survey was conducted for 12 Eup-Myeon in Yesan Gun and responses were gathered from 66 community leaders and 1,222 community members. The results derived from the data collected from the community leaders show that 50% percent of rural village communities have been operating for over 25 years, and that community works such as group purchases are carried out based on emotional sympathies between residents. The results derived from the data collected from community members show that on average, community activities are carried out at places that are between 30 and 60 minutes away. Most members are satisfied with regard to the status of their rural village community. A correlation analysis showed that the rural village community satisfaction depended on travel time, community fee, and activity time.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.5
• /
• pp.689-698
• /
• 2019

Objectives: The study aimed to investigate the relationship between depression and number of present teeth in Korean elderly individuals. Methods: Data for this cross-sectional survey was obtained from the records of the sixth Korea National Health and Nutrition Examination Survey (KNHANES). The subjects were 1,199 Korean elderly individuals above 65 years of age. The survey and examination data were used for the independent variables. The KNHANES included health status, nutrition survey, and oral examination. $x^2-test$ was performed to identify the characteristics of depression and number of teeth present according to the characteristics of the study subjects. Logistic regression analysis was also performed to identify the relationship between depression and number of teeth present. The statistical significance level wa sset at 0.05. Results: The prevalence of depression in the subjects was 14.8%. There were statistically significant differences in the prevalence of depression, depending on gender (p<0.001), education level (p=0.001), income (p=0.001), spouse status (p<0.001), and alcohol consumption (p=0.020). The association between depression and the number of teeth present showed statistically significant difference after adjustment (p=0.040). Conclusions: Depression in elderly individuals was closely related to the number of teeth present. Therefore, public health policies for improving oral health should be established to prevent depression.

• The Bulletin of The Korean Astronomical Society
• /
• v.45 no.1
• /
• pp.63.2-63.2
• /
• 2020

FLASH is a blind neutral hydrogen (HI) absorption line survey, eventually targeting about 100,000 background radio continuum sources in the entire southern sky using the full 36-antenna of the Australian Square Kilometre Array Pathfinder (ASKAP). Our primary goal is to search for associated and intervening HI absorption lines in the intermediate redshift range 0.4 < z < 1.0. The survey aims to understand the evolution of HI gas in galaxies as well as various physical mechanisms in active galactic nuclei, such as accretion and feedback processes. In this poster, we give an overview of the FLASH survey and present the preliminary results from our first 100-hrs of pilot observations. The latest survey data covers 1,000 square degrees and is ideal for validating observation and data processing in the continuous 300MHz-width low frequency ASKAP band (700-1000MHz). One of the crucial objectives of the pilot survey is to establish the analysis methodology that will be applied to upcoming large absorption surveys in the future. We discuss our data quality validation and present some detections of associated/intervening HI absorption lines. These absorption lines allow us to trace the cold gas properties of active and normal galaxies at higher redshifts where the HI emission line is too weak to be detectable.

• Korean Journal of Agricultural Science
• /
• v.39 no.1
• /
• pp.125-132
• /
• 2012

The 2009 Agricultural Survey is one of the most important official statistics about agricultural sector, which is mostly used by experts. However users have kept claiming about the problems of the 2009 Agricultural Survey, which need to be discussed in the academic area. The purpose of this paper is to analyze the 2009 Agricultural Survey and the level of satisfaction of users and to evaluate the 2009 Agricultural Survey. Then, the paper presents some suggestions to upgrade the 2009 Agricultural Survey. The results of studies present a few findings: First, the 2009 Agricultural Survey shows overall excellence but should focus on adding more various topics in agricultural sector, Second, the 2009 Agricultural Survey need to consider offering micro level data for experts such as data in the city or county level, Third, the 2009 Agricultural Survey had better to offer more specific examination and guide line for general users.

• Proceedings of the KIEE Conference
• /
• 2002.11b
• /
• pp.259-261
• /
• 2002

KEPCO(Korea Electric Power Corporation) has been management alone before some time. However through the electrical industry reorganization generation and KPX(Korea Power Exchange) were separated on 2001. A marketing and distribution part will be separated in the future. While many problem for appear in future. how to management for power system network is important. unfortunallity, electrical power industry is starting point right now. Thus, detail data is incomplete for this field and detail research for this field is required with distribution reorganazation. In this paper suggest for customer interruption cost compute method to establish a standard. The standard is need to security operation of power system network. The customer interruption cost compute method necessity of customer interruption cost compute method is minimizing process for total cost. As final total cost compute through the interruption cost compute, we can recognize investment point exactly. We cited foreign survey questions, because exactly matched survey questions for in the country circumstance is not exist. And process to survey performance suggest after modify for match in the country circumstance. Survey questions that suggested fer this paper are classified five categories. This paper suggests to detail survey questions and survey method before survey and suggest to how to customer interruption compute when survey data is ensured. Moreover this paper suggest to average interruption cost compute for residential customer using statistical method.

• Journal of the Korean Data and Information Science Society
• /
• v.15 no.4
• /
• pp.759-771
• /
• 2004

The decision tree approach is most useful in classification problems and to divide the search space into rectangular regions. Decision tree algorithms are used extensively for data mining in many domains such as retail target marketing, fraud dection, data reduction and variable screening, category merging, etc. We analyze Gyeongnam social indicator survey data using decision tree techniques for environmental information. We can use these decision tree outputs for environmental preservation and improvement.

• 한국데이터정보과학회:학술대회논문집
• /
• 2004.10a
• /
• pp.77-86
• /
• 2004

Clustering is the process of grouping the data into clusters so that objects within a cluster have high similarity in comparison to one another. In this paper we used k-means clustering of several clustering techniques. The k-means Clustering is classified as a partitional clustering method. We analyze 2002 Gyeongnam social indicator survey data using k-means clustering techniques for environmental information. We can use these outputs given by k-means clustering for environmental preservation and environmental improvement.