• Educational Technology International
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• v.6 no.1
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• pp.103-119
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• 2005

This study investigated to designand implement web-based collaborative learning system Co-Net and map out students' learning procedure using the system, based upon Student Team Achievement Division (STAD Slavin, 1990, 1996). There are technical process and instructional considerations to be made during the design process. The former are those that concern equipment requirements and specifications and include Ease of Use, Speed of Access, and Flexibility. On the other hand, instructional considerationsare concerned with the delivery and access of instructional materials and their outcomes on learners. They are cooperative interactions within groups and group heterogeneity, learner control, group incentives, individual accountability, equal opportunity for earning high scores and contributing to group effort, task specialization, and competition among groups. A web site for a virtual learning environment designed and built by the authors and known as Co-Net is then explained along with the whole process learners inside the environment. The main page of Co-Net consists of 15 menus to implement cooperative learning process. The cooperative learning activities using 15 menus are composed of six phases (1) preparation of the new knowledge (2) presentation of the new knowledge (3) knowledge assimilation and application (4) team and individual evaluation (5) team and individual recognition Throughout the five phases, the appropriate use of cooperative learning techniques has been shown to have both academic and social benefits to learners.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.257-260
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• 2004

HRTF 를 사용하여 가상적인 음향 효과를 내는 시스템에서의 음의 왜곡은 필수적이다. 하지만 음성과 같은 사람이 민감하게 느끼는 부분에서의 음의 선명도 저하는 다른 대역의 왜곡보다 더욱 크게 느껴진다. 그리고 모노 및 두 채널의 주파수 특성이 비슷한 스테레오에서는 음질을 보상할 수 없다는 단점이 있다. 본 논문에서는 이러한 음의 선명도의 저하를 유발하게 하는 가상 음향 발생 필터의 특징을 분석하고, 간단한 필터 설계에 의해서 본래의 가상 음향을 그대로 유지하면서 선명도를 높일 수 있는 방법을 제시한다. 제시한 방법은 특히 모노 및 뉴스모드와 같이 음성이 많이 들어 있는 부분에서 뛰어난 성능을 보인다.

• Journal of Communications and Networks
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• v.16 no.4
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• pp.421-429
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• 2014

We consider the problem of scheduling communications in wireless sensor networks (WSNs) to ensure battery preservation through the use of the sleeping mode of sensors.We propose a communication protocol for 1-hop WSNs and extend it to multi-hop WSNs through the use of a 1-hop clustering algorithm.We propose to schedule communications in each cluster in a virtual communication ring so as to avoid collisions. Since clusters are cliques, only one sensor can speak or listen in a cluster at a time, and all sensors need to speak in each of their clusters at least once to realize the communication protocol. We model this situation as a mathematical program.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.11a
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• pp.73-73
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• 2007

• Journal of Information Technology Applications and Management
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• v.17 no.3
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• pp.83-97
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• 2010

The purpose of this study is to examine the impacts of media symbol variety on group performance in virtual teams. Symbol variety is defined as the number of ways in which information can be communicated and includes Daft and Lengel [1986]'s multiplicity of cues and language variety. According to media richness theory and media synchronicity theory, the use of media with high symbol variety is assumed to facilitate and promote communications among virtual team members. Therefore, it is expected that the media symbol variety is positively associated with group performance in virtual teams. Furthermore, online relationship building is expected to mediate the impacts of symbol variety on the performance. To confirm the suppositions, a controlled lab experiment was conducted with 60 undergraduate students as subjects. In the experimental virtual teams, subjects were allowed to communicate with other members using text-based messenger with emoticons. Subjects in the control virtual teams were allowed to communicate using only text-based messenger. The direct impact of symbol variety on group performance in virtual teams was found insignificant. However, the online relationship was found to completely mediate the positive impact of symbol variety on group performance. The implications and limitations of this study are also discussed for future research.

• Korean Journal of Optics and Photonics
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• v.30 no.6
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• pp.237-242
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• 2019

A compact virtual-reality (VR) device with wider field of view provides users with a more realistic experience and comfortable fit, but VR lens distortion is inevitable, and the amount of distortion must be measured for correction. In this paper, we propose two different full-field distortion-measurement methods, considering the characteristics of the VR device. The first is the distortion-measurement method using multiple images based on camera calibration, which is a well-known technique for the correction of camera-lens distortion. The other is the distortion-measurement method by measuring lens distortion at multiple measurement points by rotating a camera. Our proposed methods are verified by measuring the lens distortion of Google Cardboard, as a representative sample of a commercial VR device, and comparing our measurement results to a simulation using the nominal values.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.5
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• pp.404-410
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• 2016

To avoid the stability issues of LLCL filters, passive or active damping methods to eliminate the resonance phenomena are required. In this paper, system stability of a current control is analyzed when the active damping scheme based on the virtual resister is utilized in single-phase grid converter systems with LLCL input filters. The control performance according to the parameters of the virtual resistance is investigated. The validity of stability analysis was verified by simulation and experimental results.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.629-645
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• 2022

The purpose of this study is to investigate the educational needs of virtual reality(VR)-based communication and teamwork skills for patient safety intended for nursing students and nurses. For this study, mixed method design was used with surveyed data collected 60 nursing students and 123 nurses. And fourteen nurses was conducted focus group interview. SPSS/WIN 25.0 and inductive content analysis for focus group interviews were utilized for data analysis. The results indicated that the awareness of VR and educational needs of team communication, and teamwork skills were above average, and nursing students required higher educational needs than nurses. Teamwork knowledge was moderate, and there was no significant difference between the two groups. Regarding nurse's communication in hospital, 4 themes of contributing factors and 2 themes of result factors that cause communication difficulties among nurses were derived from the qualitative data. Therefore, it is necessary to develop a virtual reality-based simulation program reflecting the educational needs of nursing students and nurses in order to improve team communication and teamwork skills for patient safety required for nursing students and nurses.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.473-475
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• 2003

To overcome the limitation that traditional GISs lose much information for the real world, 4-dimensional GIS has the additional reference systems including object's height and temporal dimension. This paper describes the 4-dimensional geometric object model and components. The prototype for 4-dimensional GIS consists of the data provider, manager, and renderer components. We show the virtual city that its database contains topographic maps, buildings, roads and temporal history data. This provides spatial, temporal operations and analysis functions.

• Journal of Internet Computing and Services
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• v.18 no.5
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• pp.103-112
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• 2017

Work engagement and job burnout are crucial problems in Korea, particularly in the business environment, and they also indicate people's motivation. Online-based teams in e-business also have these issues. Especially the role of the leader in this new type of teams is more crucial for members' motivation, behavior, and performance. Contingency leadership theories posit that different situations need different traits or behaviors of a leader. For an online-based team, which is internet-based team in e-business, a leader should use specific communication strategies to enhance a team's performance and members' motivation. In an online-based team and an offline-based team, the ways in which leaders motivate members will be different. This paper suggests particular communicative strategies for leaders of online situations. Online-based team members communicate using mobile phones or IT tools, and leaders mayinfluences members in virtual meetings. Moreover, online-based leadership needs to be more entrepreneurial and risk encouraging, and less conservative than offline-based leadership. In addition, online-based leadership should be energetic, decisive, adaptable, and inspiring, and furtherutilize communication tools such as being more gregarious/talkative, assertiveness, linguistic diversity and affect. This paper explains the roles of communicative elements such as coordination, expression, direction-giving/uncertainty reduction, empathy, meaning-making, satisfaction, and competence to decrease job burnout and to increase work engagement. The purpose of this study is to suggest communication strategies' differentiated influences on work engagement and job burnout in an online-based team.