• 한국산업정보학회논문지
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• 제12권1호
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• pp.54-60
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• 2007

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality multimedia content to the mobile environment. The system adopts the MPEG-4 standard for the main video, audio and other media format. For providing interactive contents, it also adopts the MPEG-4 scene description that refers to the spatio-temporal specifications and behaviors of individual objects. With more interactive contents, the scene description also needs higher bitrate. However, the bandwidth for allocating meta data, such as scene description is restrictive in the mobile environment. On one hand, the DMB terminal renders each media stream according to the scene description. Thus the binary format for scene(BIFS) stream corresponding to the scene description should be decoded and parsed in advance when presenting media data. With this reasoning, the transmission delay of the BIFS stream would cause the delay in transmitting whole audio-visual scene presentations, although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique in adapting the BIFS stream into the expected bitrate without any waste in bandwidth and avoiding transmission delays inthe initial scene description for interactive DMB content.

• Journal of Power Electronics
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• 제15권6호
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• pp.1628-1639
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• 2015

Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid. In this paper, a control scheme for a line-interactive UPS system applied in a low-voltage microgrid is presented. It is based on the Q-w and P-E droop control to achieve a seamless transition between grid-connected and stand-alone operation modes. Moreover, a new model for designing the controllers is built in the dq-frame based on the instantaneous power definition. The new-built model takes into account the dynamic performance of the output impedance of the inverter in the dq-frame and can be evaluated in the time domain. Compared to the traditional model based on the instantaneous power definition, the new-built model is more accurate to describe the dynamic performance of the system. Simulation and experimental results obtained with a microgrid consisting of two 40-kW line-interactive UPS systems are given to validate the control strategy of the line-active UPS system and the accuracy of the new-built model.

• 조명전기설비학회논문지
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• 제26권7호
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• pp.70-76
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• 2012

In general, the unidirectional power flow is normal in distribution feeders before activation of distributed power source such as PV. However, the interactive power flow is likely to occur in case of the power system under distributed generation. This interactive power flow can cause an unexpected effect on convectional protection coordination systems designed based only on the unidirectional power flow system. When the power line system encounters a problem, the interactive power flow can be a contributed current source and this makes the fault current bigger or smaller compared to the unidirectional case. The effect of interactive power flow is varied depending on the location of the point to ground fault, relative location of the PV, and connection method. Therefore it is important to analyse characteristics of fault current and interactive flow for various transformer connection and location of the PV. This paper proposes a method of improved protection coordination which can be adopted in the protective device for customers in distribution feeders interconnected with the PV. The proposed method is simulated and analysed using PSCAD/EMTDC under various conditions.

• 방송공학회논문지
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• 제7권1호
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• pp.28-36
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• 2002

본 논문에서는 디지털 TV 방송에서 대화형 방송 서비스를 제공하기 위한 MPEG-4 기반 대화형 방송 시스템을 제안한다. 제안한 시스템은 ATSC(Advanced Television Systems Committee) 플랫폼 기반 데이터 방송 시스템에 MPEG-4 데이터를 저작하는 기능. MPEG-4 데이터를 MPEG-2 TS(Transport Stream)로 캡슬화하는 기능, MPEG-4 데이터를 MPEG-2 프로그램과 동기화하는 기능. MPEG-4 데이터를 MPEG-2 TS에서 역다중화하는 기능, MPEG-4 데이터를 복호화/출력하는 기능 및 IP 망을 통한 대화형 기능을 지원할 수 있도록 설계하였다. MPEG-4 기반 대화형 방송 시스템은 사용자에게 강력한 대화형 기능을 제공할 수 있으며. 데이터 방송 국제 규격인 ATSC. DVB 플랫폼(platform)을 대체할 수 있는 장점이 있다.

• 정보교육학회논문지
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• 제3권1호
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• pp.13-21
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• 1999

구성주의적 관점에서 교수-학습의 과정을 설명하고자 하는 노력들은 웹 기반 교수-학습체제 설계 과정의 중심을 학습자에게로 옮겨 놓았고 웹 환경에서도 학습자에게 인간의 면대면 의사소통과 동질의 학습환경을 제공하고자 하는 설계적 관심은 최적정 상호작용성을 구현하기 위한 처방적 전략으로 제시되고 있다. 상호작용 설계의 과정은 학습자와 체제간의 기계적, 물리적, 외현적인 교류는 물론 인지적, 정의적, 내면적 측면의 암묵적 교환을 포괄하는 측면에서 이루어져야 하고 이것은 웹 기반 교수-학습체제의 설계에도 예외없이 적용된다. 학습목표, 학습내용 및 학습자 특성과 더불어 웹 고유의 환경적 특성이 상호작용 설계에 통합되어야 한다.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.571-578
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• 2022

Objective: Cognitive-motor trainings had a positive impact on cognitive function and dual-task trainings led to improvements of global cognitive function. The brain activity of the prefrontal cortex (PFC) is another indicator that can infer cognitive function. This study aims to confirm the usability of the interactive system cognitive-motor training program and the changes in the prefrontal cortex through training. Design: Cross-sectional study Methods: In this study, two cognitive tasks were randomly applied to 20 adults as cognitive-motor training using an interactive system, and the same task was performed using the original method. During all tasks, the brain activity of the prefrontal cortex was measured by the change in oxyhemoglobin (HbO) in real-time using Functional Near-Infrastructure. After performing the tasks, the usability of the developed interactive system was evaluated by a usability questionnaire which consists of five items, and each item consists of a 7-point Likert scale that responds from 1 point to 7 points. Results: The HbO levels were increased during cognitive task performance than at the resting phase. And evaluating the usefulness of the interactive system, a questionnaire result showed that it would be useful for cognitive-motor programs. Conclusions: The cognitive-motor training using the interactive system increased the activity of the prefrontal cortex, and the developed wearable sensor-based interactive system confirmed its usefulness.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2693-2695
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• 2003

Recent advancement in technology raises fundamental questions: "what is right technology for human?", "how can we build machines for human welfare?" Interactive technology and soft engineering deals with these problems. Personal robotics for the elderly seems to be a major area in which to explore these ideas. We can start by asking "what are inhumane human conditions to be resolved by technology?" Issues lain robotics for the elderly are described and desirable roles for the robots in such applications are presented. Interdisciplinary science approach is proposed to successfully implement this technology for the elderly.

• Journal of Power Electronics
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• 제2권4호
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• pp.258-267
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• 2002

This paper presents the principal features of the software modules developed to provide an interactive teaching/learning environment in Power Electronics that can be used by educators and students. The software modules utilize an object oriented programming LabVIEW that provides a highly flexible graphical user interface. The paper highlights the principal features the software components and illustrates a number of highly interactive graphical user interfaces of selected Power Electronics circuits and systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2670-2675
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• 2003

A human-friendly interactive system, based on the harmonious symbiotic coexistence of human and robots, is explored. Based on interactive technology paradigm, a robotic cane is proposed for blind or visually impaired travelers to navigate safely and quickly among obstacles and other hazards faced by blind pedestrians. Robotic aids, such as robotic canes, require cooperation between humans and robots. Various methods for implementing the appropriate cooperative recognition, planning, and acting, have been investigated. The issues discussed include the interaction of human and robot, design issues of an interactive robotic cane, and behavior arbitration methodologies for navigation planning.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2687-2692
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• 2003

Recent advancement in information technology requires new interpretations for the space among human, machines and environment. Investigation of space between information and human could lead to the proper ways, in which human and machines meet. Various concepts regarding space have been explored in terms of “virtual reality in cyberspace” and “embodiment in tangible space.” “Mom (embodiment),” space, virtuality, sensation/perception, and interactive technology are some of the key ideas to be explored. Human “Mom” is such a fundamental membrane through which human can interact with the environment physically and mentally. An embodied interaction paradigm, based on “Mom,” is investigated. This leads to interactive technology paradigm. Sound space is an invisible but a tangible space in a sense that it travels in emotional tremors and stimulates new sensations and perceptions. Three cases are introduced to experiment such tangible space as a new and proper interactive paradigm. Also, a historical model of interaction is reviewed, which includes electrical, symbolic, textual, graphical, tangible, and social interaction.