• 한국과학교육학회지
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• 제32권9호
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• pp.1452-1469
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• 2012

This study examined the science learning environments experienced by Korean and U.S. preservice elementary science teachers during their 3-week clinical experience. Observational experiences of 97 Korean and 112 U.S preservice teachers were surveyed with an instrument that we developed for the study. Follow-up interviews provided a clearer picture of what preservice teachers observed and experienced in science classrooms during their clinical experiences. Korean preservice teachers experienced a variety of science teaching environments, whereas the U.S. preservice teachers reported limited opportunities to observe science teaching and learning in terms of 6 identified facets that we posed. Along with our interpretation of the contrast in findings, some of the challenges are discussed in providing preservice teachers with opportunities to observe, experience, and teach in effective science learning environments during the clinical experience.

• 전기학회논문지
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• 제66권1호
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• pp.114-120
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• 2017

The work present in this paper deals with a navigation problem for multiple mobile robots in unknown indoor environments. The environments are completely unknown to the robots; thus, proximity sensors installed on the robots' bodies must be used to detect information about the surroundings. The environments simulated in this work are dynamic ones which contain not only static but also moving obstacles. In order to guide the robot to move along a collision-free path and reach the goal, this paper presented a navigation method based on fuzzy approach. Then genetic algorithms were applied to optimize the membership functions and rules of the fuzzy controller. The simulation results verified that the proposed method effectively addresses the mobile robot navigation problem.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.940-944
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• 2001

Shock environments are generally classified two categories; One is mechanical shock environments encountered in handling, transportation, and service environments. The other is pyrotechnic shock (or pyroshock) environments generally initiated by firing of an ordnance item to separate or release a structural member of fastener. The objective of this paper is to present a set of shock test methods - specific characteristics induced by many shock test devices, test objects properties, and shock environments. In addition, it is introduced the application of shock test in Korean aerospace development program and others with shock test facilities of Korea Aerospace Research Institute.

• Mycobiology
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• 제47권2호
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• pp.165-172
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• 2019

Species that belong to Penicillium section Sclerotiora are commonly found in various terrestrial environments, but only a few have been reported in marine environments. Because the number of Penicillium species reported in marine environments is increasing, we investigated the diversity of Penicillium section Sclerotiora in marine environments in Korea. Based on sequence analyses of b-tubulin and calmodulin loci, 21 strains of section Sclerotiora were identified as P. bilaiae, P. daejeonium, P. exsudans, P. herquei, P. cf. guanacastense, P. mallochii, P. maximae, and P. viticola. Three of them were confirmed as new to Korea: P. exsudans, P. mallochii, and P. maximae. Here, we have provided detailed morphological descriptions of these unrecorded species.

• Human Ecology Research
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• 제60권4호
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• pp.497-505
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• 2022

This study aims to examine the mediating role of peer attachment between affective school environments and the problematic behaviors of children using data from the Panel Study on Korean Children 10th wave (2017). Descriptive statistics, reliability analysis, correlation analysis, multiple regression analysis, Sobel test, and bootstrapping versification were performed using SPSS 28.0 and Process Macro 28.0. The results indicate that controlled and rigid school environments were negatively associated with peer attachment and positively associated with both internal and external behavior problems. Furthermore, peer attachment was negatively associated with both internal and external behavioral problems. Peer attachment completely mediated the link between affective school environments and internal behavioral problems, and partially mediated the link between affective school environments and external behavioral problems. These results show the important role of supportive and democratic school environments regarding peer attachment.

• International Journal of Internet, Broadcasting and Communication
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• 제15권4호
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• pp.107-114
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• 2023

In this paper, the results of experiments conducted in indoor wired and outdoor wireless environments to reduce the interference impact of 5G mobile communication on fixed satellite services using RF Interference Reduction Module (IRM) are presented. Test results for interference signals with a 100MHz bandwidth in a wired environment demonstrate that RF IRM can reduce interference by more than 20dB in a 100MHz bandwidth. The performance of RF IRM was also tested in the S-band wireless environments. In the S-band wireless environments with interference signals having a 20MHz bandwidth, RF IRM exhibits interference reduction performance of 12-15dB, for signals with a 50MHz bandwidth, it shows 10-12dB interference reduction, and for signals with a 100MHz bandwidth, it demonstrates 5-10dB interference reduction. This paper shows that RF IRM can be used not only within transceivers but also in wireless environments to mitigate interference.

• International Journal of Control, Automation, and Systems
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• 제5권6호
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• pp.674-680
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• 2007

The probabilistic roadmap (PRM) method, which is a popular path planning scheme, for a manipulator, can find a collision-free path by connecting the start and goal poses through a roadmap constructed by drawing random nodes in the free configuration space. PRM exhibits robust performance for static environments, but its performance is poor for dynamic environments. On the other hand, reinforcement learning, a behavior-based control technique, can deal with uncertainties in the environment. The reinforcement learning agent can establish a policy that maximizes the sum of rewards by selecting the optimal actions in any state through iterative interactions with the environment. In this paper, we propose efficient real-time path planning by combining PRM and reinforcement learning to deal with uncertain dynamic environments and similar environments. A series of experiments demonstrate that the proposed hybrid path planner can generate a collision-free path even for dynamic environments in which objects block the pre-planned global path. It is also shown that the hybrid path planner can adapt to the similar, previously learned environments without significant additional learning.

• Journal of Information Technology Applications and Management
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• 제14권1호
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• pp.179-202
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• 2007

This paper presents and tests a conceptual model of Technology Acceptance Model (TAM) that explains perceived usefulness, perceived ease of use, organizational commitment and turnover intention in terms of psychological commitments in mandatory environments. The model focuses on the psychological commitments (Kelman's internalization, Identification, compliance) as the primary predictors of perceived usefulness, perceived ease of use and organizational commitment. We discuss our current understanding of technology acceptance as well as the notion of mandated use. The results are as fellows that organizational commitment is negatively related to turnover intention : perceived usefulness is positively related to organizational commitment : psychological commitments are positively related to organizational commitment, perceived usefulness and perceived ease of use : perceived ease of use is positively related to perceived usefulness in mandatory environments. Through this research, psychological commitments are the strong determinants of technology acceptance in mandatory environments. These findings advance theory and contribution to the foundation for future research aimed at Improving our understanding of user adoption behavior in mandatory environments.

• 대한음성학회지:말소리
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• 제48호
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• pp.141-153
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• 2003

Researches into robust recognition in noise environments, especially in car environments, are being carried out actively in speech community. In this paper we will report on three types of corpora that SiTEC (Speech Information TEchnology & industry promotion Center) has created for research into speech recognition in car noise environments. The first is the recordings of 900 Korean native speakers, distributed according to gender, age, and region, who uttered application words in car environments. The second is the collections of mixed noise in 3 car types by model while setting up various noise patterns which can be obtained with the car engine on or off, at different driving speed, and in different road conditions with windows open or closed. The third is the recordings of simulated speech by HATS (Head and Torso Simulator) in car environments with the internal and external noise factors added. These three types of recordings were all made through synchronized 8 channel microphones that are fixed in a car. The creation and applications of these corpora will be reported on in detail.

• 노동경제논집
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• 제39권1호
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• pp.33-55
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• 2016

본 연구는 근로환경이 근로자의 객관적 주관적 보상과 어떠한 관계를 가지는지를 분석함으로써 한국노동시장에 나쁜 근로환경에 대한 보상이 존재하는지를 확인하고 시사점을 제공한다. 근로자가 당면하고 있는 다양한 근로환경과 보상지표를 제공하는 한국근로환경조사(KWCS) 자료를 사용하여 분석한 결과 나쁜 근로환경을 대표하는 위험성은 임금과 유의미한 관계를 보이지 않는 반면 보상만족도와는 부(-)의 관계로 나타난다. 이는 근로자들은 나쁜 근로환경에 대한 보상이 이루어져야 한다고 인식하고 있으나 실제 노동시장에서는 금전적 보상이 이루어지지 않는다는 것을 시사한다. 또한, 노동시장에서 물리적인 위험요인보다 정신적인 위험요인에 대한 기대 보상수준이 높게 나타나며, 이러한 경향은 남성에 비해 여성이 더 크게 나타난다.