• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.33-40
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• 2009

The critical lag of crosswalk pedestrians is an important parameter in analyzing traffic operation at unsignalized crosswalks, however there is few research in this field in Korea. The purpose of this study is to develop a model to estimate the critical lag. Among the elements which influence the critical lag, the age of pedestrians and the length of crosswalks, which have fuzzy characteristics, and the each lag which is rejected or accepted are collected on crosswalks of which lengths range from 3.5 m to 10.5 m. The values of the critical lag range from 2.56 sec. to 5.56 sec. The age and the length are divided to the 3 fuzzy variables each, and the critical lag of each case is estimated according to Raff's technique, so a total of 9 fuzzy rules are established. Based on the rules, an ANFIS (Adaptive Neuro-Fuzzy Inference System) model to estimate the critical lag is built. The predictability of the model is evaluated comparing the observed with the estimated critical lags by the model. Statistics of $R^2$, MAE, MSE are 0.96, 0.097, 0.015 respectively. Therefore, the model is evaluated to explain the result well. During this study, it is found that the critical lag increases rapidly over the pedestrian's age of 40 years.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.233-239
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• 2006

Most research for until at now link travel time were research for mean link travel time calculate or estimate which uses the average of the individual vehicle. however, the link travel time distribution is divided caused by with the impact factor which is various traffic condition, signal operation condition and the road conditional etc. preceding study result for link travel time distribution characteristic showed that the patterns of going through traffic were divided up to 2 in the link travel times. therefore, it will be more accurate to divide up the link travel time into the one involving delay and the other without delay, rather than using the average link travel time in terms of assessing the traffic situation. this study is it analyzed transit hour distribution characteristic and a cause using examine to the variables which give an effect at link travel time distribute using simulation program and determinate link travel time distribute ratio estimation model. to assess the distribution of the link travel times, this research develops the regression model and the fuzzy model. the variables that have high level of correlations in both estimation models are the rest time of green ball and the delay vehicles. these variables were used to construct the methods in the estimation models. The comparison of the two estimation models-fuzzy and regression model- showed that fuzzy model out-competed the regression model in terms of reliability and applicability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.51-57
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• 2020

WSN is a wirelessly configured network of sensor nodes with limited power such as batteries. If the sensor node's battery is exhausted, the node is no longer available. Therefore, if the network is to be used for a long time, energy consumption should be minimized. There are many Wireless Sensor Network Protocols to improve energy efficiency, including Cluster-based and chain-based Protocols. This paper seeks to examine the performance evaluation of routing protocols studied separately for the improvement of performance in wireless sensor network. The criteria for comparison were selected as the LEACH protocol, a representative hierarchical routing protocol, and the comparison targets considered CHEF and FLCFP and LEACH-DFL routing protocols with Fuzzy Logic. Various criteria for performance comparison were presented in this paper, and the performance was compared through simulation of each protocol. The purpose is to present a reference point for comparing the performance of other protocols through the performance comparison of CHEF, FLCFP, and LEACH-DFL, protocols with LEACH and Fuzzy Logic, and to provide additional design methods for improving the performance of protocols.

• Journal of Korea Water Resources Association
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• v.46 no.8
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• pp.857-871
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• 2013

The interest in rainfall observation and forecasting using remote sensing method like RADAR (Radio Detection and Ranging) and satellite image is increased according to increased damage by rapid weather change like regional torrential rain and flash flood. In this study, the basin runoff was calculated using adaptive neuro-fuzzy technique, one of the data driven model and MAPLE (McGill Algorithm for Precipitation Nowcasting by Lagrangian Extrapolation) forecasted precipitation data as one of the input variables. The flood estimation method using neuro-fuzzy technique and RADAR forecasted precipitation data was evaluated. Six rainfall events occurred at flood season in 2010 and 2011 in Chungju Reservoir basin were used for the input data. The flood estimation results according to the rainfall data used as training, checking and testing data in the model setup process were compared. The 15 models were composed of combination of the input variables and the results according to change of clustering methods were compared and analysed. From this study was that using the relatively larger clustering radius and the biggest flood ever happened for training data showed the better flood estimation. The model using MAPLE forecasted precipitation data showed relatively better result at inflow estimation Chungju Reservoir.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.642-642
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• 2012

최근에 들어 지구온난화에 따른 기후변화의 영향으로 국지성 집중호우와 돌발성 호우가 한반도 뿐 아니라 전 세계적으로도 많이 나타나고 있고, 그로 인한 이상홍수의 발생이 우리나라의 인명 및 재산피해를 날로 증가시키고 있는 추세이다. 그러나 현재 국내의 홍수방어시스템은 정확도 및 선행시간 확보 등의 측면에서 국민들의 요구수준까지는 그 역할을 수행하지 못하고 있는 실정이다. 또한 최근 4대강 살리기 사업을 통해 수행된 보 설치 및 하도 준설로 인해 하천환경의 변화가 크게 발생하여, 보다 정확하고 신속한 홍수위 예측기법이 요구되고 있는 실정이다. 이에 따라 현재 4대강 홍수통제소에서는 정확한 홍수위예측을 위해 4대강 본류 및 주요 지류에 대해 수리모형을 구축하고 있고, 기존의 저류함수모형에 의한 강우-유출 해석기법을 적용하여 주요 지류에 대한 유입량을 산정하기 위한 모형을 구축중에 있다. 국내 홍수방어 시스템에 현재까지 사용되어 오고 있는 저류함수모형 및 수위-유량 관계식을 이용한 방법은 물리적 기반의 홍수예측모형으로 유역의 지형학적 인자와 그에 따른 여러 변수를 포함하기 때문에 하천환경의 변화로 인해 각각의 추적과정에서 오차들이 발생하여 해석결과에 영향을 미치는 단점이 있다. 이에 반해 데이터 기반 모형은 강우-유출 모형에서 사용되는 많은 수문학적 자료 및 매개변수들의 사용 없이 오직 수위 및 강우측정 자료만을 이용하여 홍수를 예측하는 모형이다. 본 연구에서는 낙동강 유역에 대해 보다 정확한 홍수위 예측을 위해 현재 낙동강홍수통제소에서 구축중인 낙동강 본류의 수리모형의 주요 지류의 유입량 산정을 위해 기존의 물리적 기반 모형이 아닌 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 data 기반 모형을 적용해 기존 물리적 기반 모형과 비교 분석 하고자 하였다. 낙동강의 주요지류인 감천, 금호강, 남강, 내성천, 밀양강, 반변천, 위천, 황강을 적용유역으로 선정하여 유역별로 티센망을 구축하였고, 각 지류별로 수위관측소를 선정하여 최근 10년동안 낙동강유역의 홍수예 경보가 발령되었거나 많은 비가 온 사상을 선정해 모형을 검증하였다. 모형은 실시간 수위측정 자료와 강우자료 및 해당유역 댐의 방류량 자료를 이용해 유역별 최적 입력자료 조합을 선정하여 간단하게 구축할 수 있었다. 또한 10분 단위 및 30분 단위의 입출력 자료로 모형을 구축하여 비교하였다. 이번 연구에서 수행한 낙동강유역에서의 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 홍수예측기법을 통해 몇가지 data만으로 유역의 주요지점에 대한 홍수위와 홍수량을 예측할 수 있음을 확인할 수 있었다. 모의 결과는 실측치와 비교해 정확도 면에서 우수함을 보여 주었으나 예측시간이 길어질수록 실측치의 경향을 벗어나는 결과를 보였다. 그러나 실시간 홍수예 경보에 있어서는 만족할만한 선행시간을 확보할 수 있었다. 구축된 Data 기반 모형이 물리적 기반 모형과 더불어 낙동강 홍수예 경보를 위한 모형으로 사용될 수 있다면 보다 효율적인 예 경보 체계 구축에 도움을 줄 수 있을 것으로 판단된다.

• Korean Journal of Social Welfare Studies
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• v.48 no.2
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• pp.71-95
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• 2017

This study aims (1) to identify whether real terms of imprisonment for sexual offenders against children are different between the first trial and appeal trial in 16 cases and (2) to assess which sentencing factors such as history of sexual crime of perpetrator, forgiveness of children, regretfulness of perpetrator, power of perpetrator, and relationship of perpetrator and victim influence sentencing period of imprisonment in the first and appeal trials, respectively. This study used cases which were prosecuted for sexual crimes against children since the protection act on the children and juveniles from sexual abuse was enacted in 2000. The target cases of the study include 8 first trials and 8 appeal cases which were appealed to the Supreme Court between 2000 and 2015. Result condition is the real term of imprisonment. Cause conditions include sentencing factors such as history of sexual crime, regretfulness, and power of perpetrator, forgiveness of child, and relationship between offender and victim. We employed Qualitative Comparative Analysis (QCA) for data analysis. We found that there are sentences in the first trial with lower terms than appeal trial regarding child sexual crimes. In addition, we found that (1) power of perpetrator and forgiveness of victim significantly influenced sentencing periods of imprisonment at levels of courts; (2) cause condition considered as comparatively more important in the first trial was regretfulness of perpetrator(but not in the appeal trial); and (3) relationship of perpetrator and child was not important in sentencing for sexual crime at both levels of trials.

• Information Systems Review
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• v.19 no.3
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• pp.127-154
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• 2017

This study aims to identify various service innovation patterns in the service industry and understand the main differences among them. We attempt to create a new typology of service innovation by analyzing its patterns based on the four major dimensions of service innovation (i.e., service concept, service delivery, customer interaction, and technology). We then investigate whether firms pursuing different service innovation patterns significantly differ from one another in terms of their performance (high and low performance). Based on empirical data collected from 198 Korean firms in the knowledge-intensive business service sector, four major clusters composed of different service innovation dimensions are identified. These four clusters can be interpreted as specific service innovation patterns, including "technology based high customer interaction," "high technology based high service delivery," "service delivery and high customer interaction-integrated," and "strongly balanced" innovators. High firm performance does not depend on the individual service innovation dimension but on the specific configurations of such service dimensions. Customer interaction also has an important role in achieving innovation success and improving firm performance, while technology has a key role in enhancing firm performance. This study sheds new light on service innovation research by developing a new typology of service innovation, identifying four major clusters as service innovation patterns, and exploring the relationship between service innovation patterns and firm performance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.73-80
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• 2004

Recently, many maritime accidents have been increased and the collisions due to human error are given a great deal of proportions out if them We develop the Real-time Collision Risk Monitoring System (CRMS) for the navigational officers to cope with the emergency situation promptly and thus to reduce the probability if casualty. In this study, the risk of collision is evaluated by two kinds if method. The first method is based on Fuzzy algorithm, which evaluates the risk of collision between traffic ships. The second method is based on Environmental Stress (ES) Model, where the total risk if collision is evaluated by the environmental stress felt by human. The developed real-time CRMS has been installed to the ship handling simulator system and its capabilities have been tested through simulator experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.6
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• pp.824-834
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• 1993

In cellular mobile communication systems, if the size of a cell is decreasing for economic utilization of frequency resources, frequent handovers may be requested because the time a mobile stays in a cell is decreasing. In general the measured parameters to decide handover including RSSI, BER, and the distance between mobile station and base station, are usually incorrect and handover decision using single parameter insufficient. Therefore, the better handover algorithm should take over the problems of this uncertain measurements, and make the decision more robust and flexible by the consideration of all those decision parameters at the same time. We propose a novel handover algorithm based the multicriteria decision making, in which those parameters are participated in the decision process using aggregation function in fuzzy set theory. As a simulation results, the overall decision making is more reliable and flexible than the conventional method using only one parameter, RSSI in terms of call force ratio, and handover request ratio.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.68-74
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• 2014

In a previous work, we proposed a novel approach of histogram equalization using a supplement set which is composed of centroids of Fuzzy C-Means of the background utterances. The performance of the proposed method is affected by the size of the supplement set, but it is difficult to find the best size at the point of recognition. In this paper, we propose a histogram equalization using a supplement set for majority voting based speaker identification. The proposed method identifies test utterances using a majority voting on the histogram equalization methods with various sizes of supplement sets. The proposed method is compared with the conventional feature normalization methods such as CMN(Cepstral Mean Normalization), MVN(Mean and Variance Normalization), and HEQ(Histogram Equalization) and the histogram equalization method using a supplement set.