• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2543-2551
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• 1997

This paper proposes a compression technique of image data, a variable length PN code and channel models which are required in CDMA communication system. It also analyzes their performances. Original images is compressed by 2-D DCT and its coefficients are quantized by optimal quantizer at compression rate 0.84bit/pel. Channel model 1 and 2 which are composed of 5 and 4 channels respectively are employed to be used in CDMA. Such a situation forces us to empoly variable length PN code, such as Chebyshev map for spread spectrum system. When average PN code length of model 1 and 2 is 44.4 and 26.7 chips respectively, the received image through these models under Gaussian noise with variance 1.75 is visually of the same quality as the transmitting image. Thus, the model 2 appears to be better in channel efficiency, comparing with channel model 1 and channel model which uses fixed length PN code.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.214-218
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• 2008

하천의 유황특성을 평가 하는 것은 하천생태계의 인위적인 변형을 이해하고 예측하는데 중요한 역할을 한다. 본 연구에서는 댐 건설에 따른 하류하천의 영향을 분석하고자 수문변화 지표모형을 이용하여 용수 전용댐인 영천댐을 대상으로 댐 건설전 후의 유황변동을 분석하였다. 분석결과는 다음과 같다. (1) 월 평균유량은 갈수기와 홍수기 모두 댐건설 후 감소하였다. (2) 연 극치유량의 크기와 기간 분석결과, 댐 건설전 후의 1일 최소유량은 $3.48\;m^3/sec$와 $0.89\;m^3/sec$ 이였으며, 1일 최대유량은 $833.1\;m^3/sec$와 $672.1\;m^3/sec$ 이었다. (3) 연극치 유량의 발생시기 분석결과, 최소유량의 Julian Day는 댐 건설전 180 일(6월), 댐 건설 후 257 일(9월)이었으며, 최대유량의 Julian Day는 댐 건설전 209 일(7월), 댐 건설 후는 217 일(8월)에 발생하였다. (4) 홍수맥파의 빈도와 기간의 분석결과, 저맥파(Low Pulse)의 발생횟수는 댐 건설전 3회, 지속기간은 23 일, 댐 건설 후에는 7회, 지속기간 61 일 이었으며, 고맥파(High Pulse)의 발생횟수는 댐 건설 전 4회 지속기간은 2 일, 댐 건설후에는 2회 1.2 일로 분석되었다. (5) 변화율과 빈도의 분석결과, 상승율은 댐 건설 전, 후의 각각 39.27 %와 19.36 %로 댐 건설 전에 수문변동이 크게 발생하였으며, 감소율은 각각 -15.85 %와 -8.16 %로 분석되었다. (6) 분산정도를 변동계수로 분석하였으며, 1일 최소 최대유량은 0.9054에서 0.6314와 1.0440에서 0.9617로 모두 감소하였으며, 연 극치유량 발생시기는 댐 건설전 후 최소유량은 0.269에서 0.282, 최대유량은 0.069에서 0.153으로 댐건설이후 변동계수가 증가하였다.

• The Korean Journal of Applied Statistics
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• v.29 no.6
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• pp.1077-1094
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• 2016

Apache Spark is a fast and general-purpose cluster computing package. It provides a new abstraction named resilient distributed dataset, which is capable of support for fault tolerance while keeping data in memory. This type of abstraction results in a significant speedup compared to legacy large-scale data framework, MapReduce. In particular, Spark framework is suitable for iterative machine learning applications such as logistic regression and K-means clustering, and interactive data querying. Spark also supports high level libraries for various applications such as machine learning, streaming data processing, database querying and graph data mining thanks to its versatility. In this work, we introduce the concept and programming model of Spark as well as show some implementations of simple statistical computing applications. We also review the machine learning package MLlib, and the R language interface SparkR.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.13-20
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• 2012

In this study, the change pattern of hydrological response function as development has been observed. The target watershed was selected Tanbu sub-Basin in the Bocheong Basin. The applied channel networks are composed of 10 cases that are channel networks by strahler's ordering scheme and cases of all grids channel or the hillslope in basin. To each case of grid in basin, channel and hillslope drainage path lengths to outlet of basin are calculated, and hydrological response function was calculated by Nash Model. As results of this analysis, the peak discharge of hydrological response function is increased and peak time is shortened as development of channel networks. And based on statistical characteristics of hydrological response function, mean (lag time) and variance of travel time are reduced exponentially.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.26-30
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• 2011

최근 기후변화에 따라 강우의 패턴이 변화하고 있다. 강우일수는 줄어드는 반면, 강우강도는 증가하여, 홍수로 인한 많은 피해에 직면하고 있다. 이러한 기상이변은 홍수방어시스템을 위한 수공구조물에도 많은 영향을 미친다. 수공구조물을 설계할 때, 일반적으로 강우 기록들의 통계적 특성이 정상성을 가진다고 가정한다. 하지만 최근의 강우 자료를 분석하면, 시간에 따라 평균, 분산, 왜곡도와 같은 기본 통계량이 변화하는 것을 알 수 있다. 따라서, 수공구조물의 설계를 위한 확률 강우량은 이러한 기후변화에 따른 자료의 특성을 반영할 필요가 있다. 본 연구의 목적은 강우 자료의 비정상성의 특성을 이용하여 확률강우량을 산정하는 것이다. 최근 비정상성 강우빈도해석에 대한 연구가 활발히 진행되고 있는데, 이들 연구는 대부분 목표연도까지 경향성의 기울기가 증가, 또는 일정하다고 가정한다. 하지만, 현재는 경향성이 있지만, 목표연도에는 경향성이 없을 경우도 있고, 또는 경향성이 있어도 그 기울기가 적어지는 경향을 보일 수도 있다. 본 연구에서는 현시점과 목표연도의 시점에 대한 경향성 기울기의 변화를 고려하여 비정상성 강우빈도해석을 수행하였다. 대상지점 선정은 통계적 경향성 검정, Mann-Kendall test를 이용하여 1994년(현재시점)에 경향성이 있다고 판단되는 관측지점을 대상지점으로 선정하였다. 분석 방법은 24시간 임계지속시간의 연최대강우자료를 구축하였다. 자료를 현시점까지 선형회귀식을 이용하여 잔차 계열을 산정하고, Gumbel 분포를 이용하여 확률 잔차를 산정하였다. 확률강우량을 추정하기 위해 추세요소를 산정하였다. 기울기의 증가 혹은 감소 경향을 회귀모형을 이용하여 추세요소를 산정하였고, 잔차의 확률빈도와 추세요소의 합으로 비정상상 확률강우량을 산정하였다.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.955-962
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• 2018

The purpose of this study was to examine the awareness of sexual harassment and investigate on the factors influencing of the sexual harassment among nursing college students. This study used a descriptive research design. The participants of this study were 366 nursing college students at 2 universities in the J area. The collected data were analyzed by SPSS/WIN 22.0 program as follows. The data were analyzed using t-test, ANOVA, pearson's correlation coefficient and multiple regression. Average score were 3.45 for awareness of sexual harassment. Awareness of sexual harassment was significantly affected by gender, age. The awareness of sexual harassment of nursing college students showed a significant correlation with self-esteem and gender role stereotypes. The gender and gender role stereotypes and self-esteem was an important predictor for the awareness of sexual harassment among nursing college students with the explanatory power was 13.4%.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.692-700
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• 2020

The purpose of this study was to investigate the degree of optimism, academic resilience, and major satisfaction of nursing students, and identify influencing factors of major satisfaction. The study was a cross-sectional descriptive correlational design. A convenience sample of 286 nursing students was conducted from a university in Busan. Data were analyzed through descriptive statistics, t-test, one way ANOVA, Pearson's correlation coefficient, and hierachical multiple regression analysis using IBM SPSS version 23.0. The average score of optimism, academic resilience and major satisfaction in nursing students were 3.85±0.54, 3.87±0.52 and 3.75±0.63 respectively. The degree of major satisfaction was positively correlated with optimism and academic resilience. The significant predictors of major satisfaction were optimism(β=.385, p<.001) and academic resilience(β=.356, p<.001), explaining 49.2% of the independent variables. Accordingly, in order to increase the major satisfaction level of nursing college students, it is necessary to develop a program that can improve optimism and academic resilience, and apply it in the nursing curriculum.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.585-596
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• 2013

The objective of this study is to evaluate the hybrid downscaling method combined Step-Wise Scaling (SWS) method with Regional Climate Model (RCM) simulation data for climate change impact study on hydrology area. The SWS method is divided by 3 categories (extreme event, dry event and the others). The extreme events, wet-dry days and the others are corrected by using regression method, quantile mapping method, mean & variance scaling method. The application and evaluation of SWS method with 3 existing and popular statistical techniques (linear scaling method, quantile mapping method and weather generator method) were performed at the 61 weather stations. At the results, the accuracy of corrected simulation data by using SWS are higher than existing 3 statistical techniques. It is expected that the usability of SWS method will grow up on climate change study when the use of RCM simulation data are increasing.

• Korean Journal of Social Welfare
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• v.65 no.1
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• pp.5-31
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• 2013

The principle objective of this study is to determine factors affecting social participation for physically disabled people with musculoskeletal conditions (spinal cord injury, muscular dystrophy, osteogenesis imperfecta, rheumatoid arthritis) in South Korea using ICF relevant categories of the international classification index by WHO. The subjects of this study 352 people with physical disabilities, the data were collected using ICF component(body functions, body structures, activities and participation and environmental factors) and the relevant categories deprived from ICF core sets. The collected data were evaluated with descriptive analysis, ANOVA, correlation analysis, and multiple regression analysis. The results of this study can be summarized as follow. The mental function, Neuromusculoskeletal and movement-related functions, Genitourinary and reproductive functions, Skin and related structures, Learning and applying knowledge, General tasks and demands, and Mobility positively influenced social participation in people with musculoskeletal conditions. However individual factors and environmental factors didn't statistically significant affect on social participation. The implications of the study is to examine by ICF components of universal approach on disability study and utilized the relevant ICF categories as measurement tools.

• Journal of the Korea Convergence Society
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• v.12 no.9
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• pp.307-314
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• 2021

This study examined to identify the effect of self-leadership, career decision-making self-efficacy, and critical thinking disposition on career preparation behavior in nursing students. Data were collected from nursing students attending in nursing departments in G and M cities from April to June 2019. The 208 data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis. Self-leadership(β=.331, p<.001) and critical thinking disposition(β=.302, p<.001) reported to have effect on career preparation behavior. The study model accounted for 38.7% of career preparation behavior. These results suggest that measures to promote self-leadership and career decision-making self-efficacy should be developed and operated to improve career preparation behavior of nursing students in the nursing education field.