• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1139-1149
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• 2017

Measuring tree's volume is very important input data of various environmental analysis modeling However, It's difficult to use economical and equipment to measure a fragmented small green space in the city. In addition, Trees are sensitive to seasons, so we need new and easier equipment and quantification methods for measuring trees than lidar for high frequency monitoring. In particular, the tree's size in a city affect management costs, ecosystem services, safety, and so need to be managed and informed on the individual tree-based. In this study, we aim to acquire image data with UAV(Unmanned Aerial Vehicle), which can be operated at low cost and frequently, and quickly and easily quantify a single tree using SfM-MVS(Structure from Motion-Multi View Stereo), and we evaluate the impact of reducing number of images on the point density of point clouds generated from SfM-MVS and the quantification of single trees. Also, We used the Watertight model to estimate the volume of a single tree and to shape it into a 3D structure and compare it with the quantification results of 3 different type of 3D models. The results of the analysis show that UAV, SfM-MVS and solid model can quantify and shape a single tree with low cost and high time resolution easily. This study is only for a single tree, Therefore, in order to apply it to a larger scale, it is necessary to follow up research to develop it, such as convergence with various spatial information data, improvement of quantification technique and flight plan for enlarging green space.

• Journal of the Korean Society of School Health
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• v.17 no.1
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• pp.85-95
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• 2004

Objectives : The aim of this study was to identify the trend of school health research by analyzing articles related to school health for the last 10 years. this information can be used to guide research direction for the future. Methods : This study is a descriptive study that analyzed annual data. using an objective frame of evaluation about the methodology and research domain in each paper, all the papers included in the journals concerning school health from January 1993 to December 2000 were analyzed. The data was processed statistically by frequency and percentage. Results : 455 papers in 9 journals related to school health were published. The Journal of the Korean Society of School Health had 204 articles, the highest number of any journal. most of the articles were descriptive, but the number of experimental studies increased over time. the most common research subjects were students were the greatest ones, but the trend to study both parents and teachers increased near the end of the sampling period. the most common selection of subjects appeared to be based on convenience, but probability sampling gradually increasing annually. the most common research instrument was the questionnaire and the reliability and the validity of instruments were described in approximately half of the studies. The survey was the most commonly used method of data collection. The papers that met ethical issue in data collection were less than those that did not. In addition, the papers that provided the rationale for the calculation of sample size were less than those that did not. parametric statistics were the main methods of data analysis, but some advanced statistics were used more often than simple descriptive statistics in the latter part of the sampling period. In general, limit of the studies were not frequently mentioned but more recommendations were made. regarding the characteristics of the research area, the assesment domain was remarkable. The rate of school health problem assesment was the highest among research subjects. Sex- related subjects were the highest in detail research subjects. Conclusions : The research of school health has increased quantitatively, but it is difficult to ascertain its qualitative development. Therefore, on the basis of the research completed up until now, more school-based intervention studies and longitudinal studies need to be another target for the evaluation of the effects of the school health service. as well, policy suggestion through international and cross-sectional comparison studies are needed to assist in the establishment of the long term direction of school health.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support for multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To data, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.75-84
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• 2018

Thermal stress of livestock has been issued due to recent climate change trends and this causes reproductive disorders, decreased feed consumption, immunosuppression, and increased mortality of animals. Concept of THI has been widely used to quantitatively evaluate the degree of thermal stress for animals, however use of this concept is restricted for animals living in the enclosed facilities such as mechanically ventilated broiler houses. In this study, time-based internal energy flow and variation trends of temperature and humidity were analyzed based on BES technique. Local weather data, insulation characteristics of building materials, heat and moisture generation rate from broilers according to age, algorithm of ventilation operation were adopted for boundary condition of the model to accurately compute THI values inside the mechanically ventilated broiler house. From the BES computation, excess frequency of THI threshold in Jeju city was highest on the assumption that air conditioning equipments were not installed. When general raising density ($39kg\;m^{-2}$) was adopted, total 2,191 hours were exceeded. Excess hours of THI threshold were strongly related to the cumulative air temperature ($R^2=0.87$).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1342-1347
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• 2010

Various researches have been studied on WSN(wireless sensor network) for barbed wire entanglements surveillance applications such as industry facilities, security area, prison, military area, airport, etc. Currently, barbed wire entanglements surveillance is formed wire sensor network environment. Traditional wire sensor network guarantee high data transmission rate. Therefore, wire sensor network use fast fourier transform of data of high transmission rate for extraction of feature parameter. However, wireless sensor network in comparison with wire sensor network has very low data transmission rate. Therefore, wireless sensor network doesn't use fast fourier transform of wire sensor network for extraction of feature parameter. In this paper, proposed method use 1 level approximation coefficient of DTW(dynamic time-warped) algorithms based on DWT(discrete wavelet transform) for extraction of detection feature parameter and classification feature parameter for barbed wire entanglements surveillance. l level approximation coefficient have time information and frequency information of signal. Therefore, Dynamic time-warped algorithms based on discrete wavelet transform improve detection and classification of target rather than using energy of signal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.585-596
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• 2016

This study was designed to examine the relationships among the levels of perceived stress, dietary behaviors, physical exercise, drinking, smoking, and relief from fatigue through sleep which affect the subjective happiness in adolescents. Based on the study findings, this paper proposes the basic data required for offering practical solutions to improve the subjective happiness of adolescents. IBM SPSS 20 and AMOS 23 were used to conduct frequency and descriptive analyses, in conjunction with Pearson's correlation coefficients, the AMOS bootstrapping method and phantom variables, for the raw data obtained from the 9,599 participants included in the 11th Korea Youth Risk Behavior Web-based Survey. Those factors having a direct effect on the subjective happiness of the adolescents were the level of perceived stress, relief from fatigue through sleep, physical exercise, dietary behavior and smoking. Perceived stress had an indirect effect on subjective happiness, and the analysis of the indirect effect and significance level of multiple mediators by means of phantom variables showed that, as well as perceived stress, relief from fatigue through sleep, physical exercise, dietary behaviors, and smoking also had indirect effects on subjective happiness. Consequently, a multidisciplinary approach is needed to optimize the subjective happiness in adolescents and financial support for environmental improvements is particularly necessary.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.613-628
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• 2011

Restoration, prediction and noise analysis of geomagnetic data measured in the Korean Peninsula were performed. Restoration methods based on an optimized principal component analysis (PCA) and the geostatistical kriging approach were proposed, and its effectiveness was also interpreted. The PCA-based method seemed to be effective to restore the periodical signals and the geostatistical approach was stable to fill the gaps of measurements. To analyze the noise level for each observatory, the geomagnetic time-series was plotted by scattergram which reflects the spatial variation, using data observed during same period. The scattergram showed that the observation made at Cheongyang seemed to have better quality in spatial continuity and stability, and the restoration result was also better than that of Icheon site. For the restoration, both of the methods, geostatistical and optimizaed PCA, showed stable result when the missing of observation was within 20 points. However, in case of more missing observations than 20 points and prediction problem, the optimized PCA seemed to be closer to the real observation considering the frequency-domain characteristics. The prediction using the optimized PCA seems to be plausible for one day of period for interpretation.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.2
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• pp.313-323
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• 1998

This study was a descriptive research on the level of self-care available to continous ambulatory peritoneal dialysis patients (hereinafter referred to as 'CAPD patient') related to the specific area of infection management. The method employed for the collection of data was a modified instrument of the self-care survey essentially based on Young Sook Choi's instrument. The relevant data was collected from september 1, 1996 to september 30, 1996. The subjects were provided with an open-ended question regarding the reasons behind why they did not seek self-care. The answers provided about self-care compliance were analyzed by SPSS for frequency, percentage, mean, t-test, ANOVA. Reasons for non-compliance were analyzed by content analysis. The results of the study were as follows : 1. The percentage of patients engaging in self-care were according to the following self performed tasks : preparation of dialysis : 30.58 points Dialysate exchange procedures : 49.40 points - Two bag type : 50.50 points - Spike type : 48.80 points - Neo type : 48.90 points Catheter exit site care : 25.13 points More specifically, in relation to the preparation of dialysis as referred to above, those patients engaging in self care was relatively high with respect to the cleaning of the dialysis before use and for the preservation of peritosol. However, in dialysate exchange procedures, data revealed that those patients engaging in self-care are relatively low with respect to putting on a mask during the performance of peritosol exchange. Similary in peritosol exchange procedure and catheter exit care, low levels of self-care performance were found in the area of putting on a mask during the peritosol exchange procedures and catheter line testing procedures, respectively. 2. In general characteristics, there appeared to be no distinction in self-care compliance among CAPD patients. 3. The main reasons for non-compliance were based in the following factor : intellectual, attitude, enviromental surrounding and physical. As a result of the foregoing finding, nurses should provide adequate assistance to promote self-care compliance by CAPD patients by checking the preparation of dialysis, dialysate exchange procedure, and catheter exit site care which recieved low point in this research.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.47-52
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• 2005

Obstructive Sleep Apnea (OSA) is a representative symptom of sleep disorder caused by the obstruction of upper airway. Because OSA causes not only excessive daytime sleepiness and fatigue, hypertension and arrhythmia but also cardiac arrest and sudden death during sleep in the severe case, it is very important to detect the occurrence and the frequency of OSA. OSA is usually diagnosed through the laboratory-based Polysomnography (PSG) which is uncomfortable and expensive. Therefore researches to improve the disadvantages of PSG are needed and studies for the detection of OSA using only one or two parameters are being made as alternatives to PSG. In this paper, we developed an algorithm for the detection of OSA based on Heart Rate Variability (HRV). The proposed method is applied to the ECG data sets provided from PhysioNet which consist of learning set and training set. We extracted features for the detection of OSA such as average and standard deviation of 1 minute R-R interval, power spectrum of R-R interval and S-peak amplitude from data sets. These features are applied to the input of neural network. As a result, we obtained sensitivity of $89.66\%$ and specificity of $95.25\%$. It shows that the features suggested in this study are useful to detect OSA.

• Journal of the Korean School Mathematics Society
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• v.5 no.2
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• pp.1-15
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• 2002

The purpose of this study came to start to be helpful in that the teachers in field produced evaluation subject about the mathematics and applied by analyzing the performance capacity for the students about the subject developed through the application of subject about the teaching-learning model that can utilize the learners' learning experience and the development of items that can evaluate it by utilizing various and concrete operational materials as an object of the first year at the middle schools. The concrete purpose of realizing it is as follows. 1. This study is to develop the teaching-learning model centered on activities adequate to utilize various and concrete operational materials. 2. This study is to develop evaluation data for utilizing the concrete operational materials by making construction through the application of developed teaching-learning model as possible. 3. This study is to present standards initiative for reliable and fair marking about the evaluation data and to analyze the students' practice capacity by using it effectively. For accomplishing the purpose of this research, this study is the work-oriented teaching and learning model using learning data that can be easily found around the surroundings and 8 evaluation programs in order that the experience-oriented learning based on circumstances learning among the learning models of constructivism. Also, it is to examine the result after applying that on a basis of 25 students, consisted of only on class in a year, in the first year at the small size of agricultural middle schools. The result of this study from this research is as follows. First, as a result of frequency survey, of response about the developed evaluation data it showed positive response more than 80% of all the items. The atmosphere of self-directed learning was produced because the developed evaluation data could induce activity-based learning naturally by stimulating the students' curiosity and promoting interest. Second, this study executed t-test for the result of questionnaire about the mathematics propensity, and there were significant differences in 19 items among 25 items. It presented that the application of data about the teaching-learning and evaluation directly using concrete operational materials to the constructional learning by level might have desirable affect on the students' mathematical propensity. It came to be a motive that could increase value recognition and interest on the subject of mathematics by investigating a mathematical principle rule and confirming it through activity learning using the concrete operational materials.