• Journal of Korea Water Resources Association
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• 제53권12호
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• pp.1049-1057
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• 2020

This study aimed to develop a flow measurement method using drone in flood season. Measuring flow in all branches is difficult to conduct annually due to budget and labor limitation, safety and river works. Especially when heavy rain like storm comes, changes in stage-discharge relationship should be reviewed; however, it is usually impeded by the aforementioned issues. To solve the problem, it developed a simple measuring method with a minimum of labor and time. A numeric map and numeric orthophoto coordinate of South Korea are mostly based on Transverse Mercator Projection (TM) in accordance with rectangular coordinate system and use World Geodetic Reference System 1980 (GRS80) oval figure for conversion. Applying a concept of aerial photogrammetry, it located four visible Ground Control Points (GCP) near the river at Uijeongbu-si (Singok Bridge) and Yeongdong-gun (Youngdong 2nd Bridge) station and measured the coordinates using VRS DGPS. Hovering at a same level, drones took orthophoto of water surface at an interval of 3 seconds. It defined the pictures with GRS80 TM coordinate system, a rectangular coordinate system and then conducted an orthometric correction using GCP coordinates. According to X and Y coordinate analysis, it estimated the distance between the floating positions at 3 seconds-intervals and calculated the flow through the flow area according to the flow path. This study attested applicability of the flow measurement method using drone in flood season by applying the rectangular coordinate system based on the concept of aerial photogrammetry.

• The Journal of Information Systems
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• 제18권3호
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• pp.111-134
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• 2009

Today many owners of Web sites are looking to user's satisfaction survey as a key means of measuring the usability of a Web site. While it is preferred for it simplicity and ease of use, this survey method is not without potential risks. This paper focuses on showing that the existing practice of questionnaire-based usability measurement is subject to human recall errors, and that such flaws can be reduced when the questionnaire survey is followed by the users hands-on experience of the site. An empirical study was conducted, and the results indicate that the above speculation holds true. Even if respondents felt highly confident about their responses on a recall survey, a hands-on experience with a focal Web site increased the extent to which the respondents were satisfied with the shopping mall site. This indicates that a user's perception of the quality of a Web site may be distorted or lost as time goes by. In addition, the findings have shown that the use of the verbal protocol analysis method can reveal critical information that can help track the root causes of Web site usability problems, thereby helping to develop site enhancement strategies. The paper concludes with directions for future research.

• Journal of Korean Society for Geospatial Information Science
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• 제21권4호
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• pp.117-123
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• 2013

The purpose of this research is to suggest the reasonable method of Network RTK surveying in future cadastral re-survey project through the accuracy analysis about Network RTK surveying achievement and the conventional TS-based confirmation surveying. To achieve it, we selected the experiment places and succeeded in achieving the result by Network RTK surveying about total of 307 parcel boundary point. We compared it with the result of confirmation surveying for cadastral, and it was shown that total connection errors of RMSE was ${\pm}0.1028m$ and total 48 places exceeded in the cadastral re-survey allowable error tolerance. The research suggested the practical alternatives in cadastral re-survey project after the comprehensive evaluation of those analysis results. Therefore, the author suggested development and adoptation of integrated electronic plane table surveying method. Moreover, we suggested unifying the first parcel boundary point method into the total station surveying and adopt the Network RTK surveying on the cadastral surveying inspection.

• Journal of Preventive Medicine and Public Health
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• 제29권4호
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• pp.815-829
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• 1996

A physician survey was done by mailing for the purpose of performing hospital services evaluation and ranking. A slightly over one thousand samples were drawn from the list of professional societies, and 324 physicians(about 32 percent) replied. This study has focused on developing easy and simple method to evaluate hospital services, and providing patients with useful information. Hospital service structure and process were evaluated without outcome evaluation, because it is difficult to obtain reliable data regarding health services outcome indicators. Clinical specialty was targeted to evaluate, and three specialties were chosen, that is obstetrics & gynecology, cardiology, and proctology. Among 16 structural indicators, four indicators were finally chosen in each specialty by respondent specialists. And then using these indicators, structural score was calculated for study hospitals. For process evaluation, physicians were requested to nominate five most famous hospitals. The nomination score and structural score were summed up to produce final score and hospital ranking. This method is very easy to conduct rather than other hospital services evaluation methods prevailing in Korea. And it is more useful for patients to choose hospitals, according to his/her own purpose, because it gives high ranking hospitals with specific clinical specialty.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.477-481
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• 2007

The purpose of this study is to provide the ideal forecasting model of cadastral survey work load through the Economeatric Analysis of Time Series, Granger Causality and VAR Model Analysis, it suggested the forecasting reference materials for the total amount of cadastral survey general work load. The main result is that the derive of the environment variables which affect cadastral survey general work load and the outcome of VAR(vector auto regression) analysis materials(impulse response function and forecast error variance decomposition analysis materials), which explain the change of general work load depending on altering the environment variables. And also, For confirming the stability of time series data, we took a unit root test, ADF(Augmented Dickey-Fuller) analysis and the time series model analysis derives the best cadastral forecasting model regarding on general cadastral survey work load. And also, it showed up the various standards that are applied the statistical method of econometric analysis so it enhanced the prior aggregate system of cadastral survey work load forecasting.

• Communications for Statistical Applications and Methods
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• 제16권2호
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• pp.317-323
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• 2009

Recently not even government polices but small town decisions are based on the survey data/information, so the most of government agencies/organizations demand various sample surveys in each fields for more detail information. However in conducting the sample survey, nonresponse problem rises very often and it becomes a major issue on judging the accuracy of survey. For that matters, one solution ran be using the administration data. However unfortunately most of administration data are restricted to the common users. The other solution can be the imputation. Therefore several method, of imputation are studied in various fields. In this study, in stead of the simple regression imputation method which is commonly used, factor score regression method is applied specially to the incomplete data which have the unit and item misting values in survey data. Here for simulation study, Consumer Expenditure Surveys in Korea are used.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제58권1호
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• pp.49-58
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• 2022

In September and October 2020, combined acoustic and trawl surveys were conducted in the northwestern sea of Jeju Island. In the survey area, a region, so called Jeju region, was designated to esimate the biomass of chub mackerel and jack mackerel using a trawl survey method and frequency difference method. In the September survey, the weight ratios of jack mackerel and chub mackerel to the total catch were 24.6% and 2.8%, respectively, and in the October survey, those ratios were 24.9% and 20.7%, which were used to calculate their biomass (trawl survey). Using the frequency difference range (-8 to -3dB) corresponding to two species in 120 and 200 kHz, their biomass was estimated (frequency difference method). As a result, the biomass of two species from the trawl method was 3252.3 tons in September and 5777.0 tons in October. The estimated biomass by the frequency difference method was 4926.6 tons in September and 7521.5 tons in October. It was the first trial to estimate the biomass of two species using the trawl and frequency differencing methods in South Korea although there were some differences between two methods. In addition, horizontal distributions of acoustic backscattering strength over the entire survey area were mapped.

• Survey Research
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• 제6권2호
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• pp.51-74
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• 2005

The internet survey methods have been more and more widely used as the coverage of the fixed-line telephone is being reduced due to the diffusion of mobile phone. So, there is a need to know the accuracy of this new survey method. This study aims to estimate the accuracy of the internet survey method and identify the factors affecting the accuracy of this method, For this purpose, we analyzed the election poll data during the 17th general election period. These data include fixed-line telephone survey data, internet survey data, mobile phone survey data and the election voting data. The analysis shows that the prediction errors of the internet survey were a little more than those of the telephone or mobile phone survey. But the differences are not significant. It follows from this result that we can use the internet survey method in social survey context. This study also found that the respondent's willingness to participate in the survey, the probability of being at home during survey and the respondent's educational level were affecting the accuracy of the internet survey. Further studies to develop weighting method with these factors are needed.

• Geophysics and Geophysical Exploration
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• 제11권2호
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• pp.109-115
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• 2008

It is very important to estimate the physical properties of survey area and delineate the geological basement in marine site survey for the design of offshore structures. For the purpose of providing high quality data by means of engineering site survey, it is necessary to apply several survey techniques and carry out the integrated interpretation to each other. In this study, we applied single channel seismic reflection method and OBC (Ocean Bottom Cable) type seismic refraction method at shallow marine. We used a dual boomer-single channel streamer as a source-receiver in seismic reflection survey and airgun source-the developed OBC type streamer in seismic refraction survey. We made 24 channels OBC type streamer which has 4m channel interval and each channel is composed of single hydrophone and preamplifier. We tested the field applicability of the proposed method and applied the typical seismic data processing methods to the obtained reflection data in order to enhance the data quality and image resolution. In order to estimate the geological velocity distribution from refraction data, seismic refraction tomography technique was applied. Therefore, we could successfully perform time-depth conversion using the velocity information as an integrated interpretation. The proposed method could provide reliable geologic information such as sediment layer thickness and 3D basement depth map.

• The Journal of Korean Medical History
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• 제18권1호
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• pp.89-101
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• 2005

Obejectives : This survey was accomplished to find out how Korean medical doctors think that the recognition regarding the Korean acupuncture method and research direction Methods : The survey questions were developed by the consensus from the professors who major in acupuncture and moxibustion. The questionnaire was given the 2731 Korean medical doctors at the mending education site; In addition, it was given to 793 doctors working at the 105 Korean medical hospitals listed on the National Korean Medical Hospital Associations Address book by postal mail; and also it was given to the 142 public health care Korean medical doctors who attended the conference for the municipal and provincial representatives of the public health service Korean medical doctors. Total of 1277 questionnaires were retrieved out of the 3666 subjects. Results : 1. Eleven hundred eighth seven out of 1277 Korean medical doctors think motion and bone and joint disease which has an effect in acupuncture treatment(92.9%) 2. Nine hundred fourteen out of 1277 Korean medical doctors used "Body acupuncture method"(71.5%) and 902 out of 1277 Korean medical doctors think of the korean acupuncture method which is "Sa Am acupuncture method"(70.6%) 3. Eight hundred forty out of 1277 Korean medical doctors want verification which leads a clinical research to know that acupuncturist have acupuncture and moxibustion treatment(65.7%). Conclusion : Korean medical doctors think motion and bone and joint disease which has an effect in acupuncture treatment Korean medical doctors most used "Body acupuncture method" but think of the korean acupuncture method which is "Sa Am acupuncture method". Korean medical doctors want verification which leads a clinical research to know that acupuncturist have acupuncture and moxibustion treatment.