• Phonetics and Speech Sciences
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• v.13 no.4
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• pp.75-87
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• 2021

The purpose of this study was to investigate, longitudinally, interruption behavior which children who do stutter (CWS), children who do not stutter (CWNS) and their mothers and relationship with disfluency of children showed during interactions with their mothers. Subjects for this study consisted of 2-5 year old CWS (male 2 and female 4), an age-matched group of CWNS (male 3 and female 3), and their mothers. Frequencies of normal disfluency (ND) and abnormal disfluency (AD) in children group and frequency of interruption and simultalk duration in children and mothers group were measured two times (initial visit and 12 months later) over the course of one year. As a result, no significant difference was observed in frequency of interruption and simultalk duration both between two mother groups and between two child groups at initial visit and 12 months later. However, frequency of interruption increased significantly over the course of one year in CWS group. A significant group difference was found in frequency of interruption of mothers but, no significant difference was observed in simultalk duration of mothers at initial visit. In the CWS·mothers group, no factors were related with disfluency of children at initial visit and 12 months later. These findings suggest that interruption is not just negative behavior, and that reducing interruption should be considered in child·parent interaction therapy for CWS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.191-196
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• 2004

The measurement method is proposed for performance-evaluation of bus system in this paper. The cycle tin in manufacturing system that sensor and actuator play on the role is important factor for performance-evaluation. In order to measure cycle time, proposed method is based on simple algorithm. But it must consider delay elements in PLC and it's peripheral. The test of the cycle time is divided into the best case and the worst case and parameters are set corresponding to two cases for the improvement of measurement result It is shown that the proposed method is efficient by measuring the cycle time of the fieldbus basing on the mathematics model. As a result, due to simplicity and convenience of proposed method, the engineering cost and time demanding for test of cycling time can much reduce.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.6-6
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• 2015

본 연구에서는 일단위로 제공되는 RCP 시나리오를 Poisson Cluster 기법을 활용하여 시간강우량으로 생성할 수 있는 모형을 개발하는데 목적이 있다. 일반적으로 시간단위 강우량의 경우 수자원 설계 또는 강우-유출 분석시 가장 기본이 되는 입력 자료로서 이에 대한 모의기법 확립이 기후변화에 따른 수문학적 영향 검토의 신뢰성을 결정짓는 핵심 요소이다. 그러나 국내 다수 연구를 살펴보면 기후변화 시나리오의 시 공간적 상세화 기법을 활용한 일단위 상세화 연구는 다수 존재하였지만, 일단이 이하의 시간적 규모에 대한 연구는 미진한 실정이다. 이러한 이유로 본 연구에서는 시단위 상세화 기법시 일반적으로 사용되고 있는 Poisson Cluster 기법을 활용하여 국내 실정에 맞는 시단위 상세화 기법을 개발고자 한다. 본 연구에서는 RCP 시나리오를 시단위강우량 자료로 생성하기 위해 다음과 같은 연구를 진행하였다. 첫째, 본 연구에서는 기상청에서 제공하는 RCP($27km{\times}27km$) 시나리오를 활용하였으며, 1km 격자 단위로 시공간적 상세화 기법을 수행하였다. 둘째, 시공간적으로 상세화 된 자료를 Poisson Cluster 기법을 기반으로 시간단위 자료를 생성하였으며, 기본적인 통계치(평균, 분산, 왜곡도 등)를 활용하여 관측값과 비교 분석 하였다. 마지막으로, 미래 기후변화 시나리오를 동일한 방법으로 시간단위 자료를 생성하고 연 최대값을 추출하여 빈도해석을 통해 미래 극치 확률강우량을 평가하였다. 본 연구 결과 시간단위 자료를 제공함으로써 미래 수자원 설계 및 영향평가를 효과적으로 수행할 것으로 기대되며, 수문기상변화 예측을 위한 신뢰성 있는 자료로 활용될 수 있을 것으로 판단된다.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.26-31
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• 2023

For durability improvement of polymer electrolyte membrane fuel cell (PEMFC) polymer membrane, accelerated durability evaluation methods that can evaluate durability in a short time have been researched and developed. However, the lifespan of fuel cells for large commercial vehicles such as trucks and buses is more than three times that of passenger cars, and the chemical accelerated stress test (AST) time is also longer, reaching 1,500 hours or more. Therefore, in this study, as a method to evaluate the chemical durability of a membrane within a short time, it was examined whether the durability could be predicted by the pristine membrane characteristics. Hydrogen crossover current density (HCCD) and short resistance (SR) were estimated as initial characteristics, and AST time was predicted through the Fenton experiment, which was possible as an out-of-cell experiment for 3 hours. As the HCCD and fluoride ion emission concentration increased, the AST time tended to be linearly shortened, but there was a deviation (R² ≒0.65). When the SR decreased, the AST time showed a linear increase, and the accuracy was high (R² =0.93), so the AST time could be predicted with the initial SR of the membrane.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.151-160
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• 2006

Software quality evaluation system and software evaluation criterion have to be defined to evaluate software reliability. In this study, we develop software reliability quality metrics for evaluating of software reliability and research for testing of suitable criteria of software reliability. To accomplish a study successfully, we have to estimate the failure time of software using the number of software bugs. Software reliability is very important in software quality. We propose the estimation of software reliability. We propose the software reliability metrics and the software testing method that the basis of international standard ISO/IEC 9126 in software testing metrics.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.213-220
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• 2008

In a distributed processing environment composed of many independent systems connected by networks, it is very important and difficult to make time synchronization between the systems. Especially in the USN environment the time synchronization is still more difficult than in general distributed processing environment because energy is limited and communication function is feeble. Even though of these difficulties, the USN environment requires higher precision of time synchronization. We of the typical applications requesting very strict time synchronization in USN is TDMA MAC. This paper proposes and evaluates a new time synchronization protocol HTSP(Hierarchical Time Synchronization Protocol) which is an advanced version of the FTSP(Flooding Time Synchronization Protocol) published recently. The time synchronization precision of the HTSP is equal to that of the FTSP, but the energy consumption of the HTSP is lower than that of the FTSP owing to the reduced number of broadcast messages. The simulation results show that the energy consumption of the HTSP is only 74% of that of the FTSP.

• KIISE Transactions on Computing Practices
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• v.21 no.5
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• pp.379-386
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• 2015

We propose a novel user-perceived performance optimization framework for the Android platform that takes advantage of the user-centric response time analysis. To this end, we propose a new definition of response time, which we call the user-centric response time, as a metric for the quality of user-perceived performance of the smartphone application. In this paper, we describe the design and implementation of an on-line user-centric response time analyzer for Android-based smartphones, which provides smartphone application developers with valuable insight for user-perceived performance optimization. We implemented the user-centric response time analyzer on the Android platform, version 4.0.4 (ICS) running on a Galaxy Nexus smartphone. From our experimental results, the proposed user-centric response time analyzer accurately estimates user-centric response times with an accuracy of 92.0% compared to manually measured times with less than 1% performance penalty. In order to evaluate the efficiency of the proposed framework, we were able to reduce the user-centric response time of the target application by up to 16.4% based on the evaluation results by the proposed framework.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.269-275
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• 2022

In this study, the setting time and compressive strength of cement paste composites applied with nano-micro pozzolanic binders were experimental analyzed. The pozzolanic binder was reduced initial and final setting time and the compressive strength was increased. Micro silica was effective in decrease the initial setting and final setting time and impressing the compressive strength. When two or more cement binders were used, the using of silica fume and a small amount of nano silica at reduced the setting time to 62-64 % to OPC cement and the compressive strength was increased to 117 %. A small amount of mixing the nano silica was effect to pore filling and pozzolanic activation. However, the addition of a chemical admixture should be considered when mixing table design because pozzolanic binders high specific surface area causes a decrease in cement composites flow.

• Explosives and Blasting
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• v.37 no.4
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• pp.10-16
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• 2019

Information on overpressure, positive phase duration, and impulse are required to assess the effects of shock waves or pressure waves on the structure. In this study, the overpressure and positive phase duration were determined by applying the Multi-Energy Method, which is found to be effective in analyzing the explosion of vapor clouds. Based on the total heat of combustion estimated in the cyclohexane vapor cloud explosion in the Nypro Ltd(UK), overpressure and positive phase duration at the distance of 40, 80, 120, 160, 200, 240, 280, 320, 360(m) from the source of explosion were evaluated. Overpressure was shown to decrease exponentially and positive phase duration increased almost linearly with distance. A probit function was used to assess the probability of damages for the structures at each distance using the overpressure and impact obtained at the above mentioned distances. The Analyses of probability of damages have shown that there is a high probability of collapse at distances within 120m, major damage to structures within 240m, and minor damage and breakage of window panes of structures occur over the entire distances.

• Journal of Korean Library and Information Science Society
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• v.54 no.1
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• pp.221-240
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• 2023

This study proposes a medium-specific reading instruction method for digital natives exposed to various reading media with the development of information and communication technology. For this purpose, an elementary school located in H-si, Gyeonggi-do was selected and the readability and literacy tests according to the media were conducted for 6th graders. In the experiment, the same article contents were divided into three groups, and the time required to read and read using different media was measured, and the literacy according to the media was confirmed through quizzes. As a result of the measurement, the average reading time of the web-page was 3 minutes 28 seconds, the quiz correct answer rate (average) 3.99 questions, the average reading time of the pdf file in the form of an e-book was 5 minutes 23 seconds, the correct answer rate (average) 4.35 questions, the average reading time of the printed text was 7 minutes 14 seconds, and the correct answer rate (average) 6.26 questions. The number of students who participated in the experiment is 144, and there is a limit to generalizing the reading method according to the media type only with the results of the researcher's experiment.