• 한국운동역학회지
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• 제30권4호
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• pp.301-309
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• 2020

Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.388-390
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• 2003

Recent trend of sensor-less control of induction motor applied for commuter trains in Japan is introduced. Although many inverter-fed Induction motor driven trains have been produced so far, most of them were slip frequency based conventional V/f control system using shaft encoder. There arises a new trend to apply speed sensor-less vector control., for this inverter-fed induction motor drive system. The purpose of sensor-less control is to save, cost and improve system reliability. Several sensor-less systems now under testing on the actual railway company. This paper describes the survey of the fundamental structure and feature of representative sensor-less systems mentioned above.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2001년도 추계학술대회
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• pp.3-17
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• 2001

In this paper, we compare the market performances under circuit pricing whereby users are charged based on their length of usage time and under packet pricing whereby users are charged based on the amount of information received. We show that, if packet pricing is introduced, the market price rises contrary to the government's expectation but that the overall social welfare is unambiguously increased because packet pricing reflects the social cost properly while circuit pricing does not. Also, we show that, if delivery of multi-media files requires a much higher speed, a move to packet pricing lowers the price of multi-media transmission, thereby increasing the usage of multimedia data in the absence of congestion, which may not be the case in the presence of congestion.

• 기술혁신학회지
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• 제1권1호
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• pp.83-95
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• 1998

Although an academic journal has had an important role in the diffusion of knowledge and the confirmation of knowledge advancement, it has revealed several difficulties : long processing time for publishing, uni - directional communication, closed review process etc. But an electronic journal (E-Journal) can solve these problems and add several new advantages such as the multimedia expression of documents, and pre and post publication review. Moreover, it should be noted that an E-Journal is not an alternative medium which simply replaces an existing journal, but a new paradigm for scholarly communication. Although this paper reviews several issues related to E-Journal, the introduction of the concept of universal service and informal document style for flexible communication are noticeable. For effective diffusion of E-Journal, information infrastructures such as high - speed telecommunication networks and digital libraries are urgently needed. Government subsidy as in Great Britain is necessary for E-Journal publishing.

• 기술혁신학회지
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• 제8권spc1호
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• pp.323-336
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• 2005

Digital content industry is growing rapidly because of the property of high-speed networking and greater demand for digital fulltext-image. However, we know the fact that it is many difficulty in production and supply for good quality of content. Hereupon, we suggest digital fulltext-image service framework to protect copyright. More concretely, we propose integrated model and reference model to securely serve digital fulltext-image by recompositing core objects and reconstructing the value-chain structure of digital content industry to framework including the process(from its production (creators or copyrighters) to consumption (users or consumers)). Also, we construct the digital fulltext- image service system based on reference model and reconstruct its interface that occurs between core subjects.

• 기술혁신학회지
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• 제4권3호
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• pp.342-354
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• 2001

The appearance of on-demand business model of multimedia contents is one of the biggest changes in the broadband Internet which aims at the high-speed Internet users. Currently the interest in the webcasting service, a new converged service of the broadcasting and the telecommunications, has been increased. However the quality of service is not guaranteed due to the bottleneck problem in a middle-mile as the fundamental limit of the Internet, and has not been improved greatly due to the small-scaled operators of the webcasting services. This study suggests a new business model of the multi-channel satellite webcasting service based on the satellite multicasting and content delivery network, which guarantees the quality of service and channelizes the contents by the type or by the special purpose.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2002년도 제21회 하계학술발표회 논문집
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• pp.257-268
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• 2002

Korean mobile communications industry has been a main locomotive of the drastic development of Korean IT industry and became one of core industries in national economy. To secure strong competitiveness of mobile communications industry, smooth cooperation should be reconsidered among government, universities, research institutions, and private companies. Future mobile communications technology will be evolved from IMT-2000 to system upgrade, 3.5G and 4G. And the goals of technology development are provision of mobile multimedia services based on better mobility and higher data speed rates. Therefore, Korea's technology development strategies of mobile communications should be focused on intensifying bondage of international cooperation, strengthening standardization activities, and enhancing core technology development capability to secure IPR.

• Applied Science and Convergence Technology
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• 제26권5호
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• pp.95-109
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• 2017

There are several contributions to the gas load of a system of which often the most important is outgassing. Adsorption occurs via two main processes, physisorption and chemisorption, and can be described using five (or six) classifying isotherms. Outgassing is the result of desorption of previously adsorbed molecules, bulk diffusion, permeation and vapourisation. Looking at the desorption rate, pumping speed and readsorption on surfaces, the net outgassing of the system can be calculated. There is significant variation in measured outgassing rates between different materials but also between published rates for the same materials, in part due to the number of different methods used to measure outgassing. This article aims to review the outgassing process, outgassing rates, measurement methods and techniques that can be used to reduce the outgassing of a system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.998-1001
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• 2003

Recent trend of sensor-less control of induction motor applied for commuter trains in Japan is introduced. Although many inverter-fed induction motor driven trains have been produced so far, most of them were slip frequency based conventional V/f control system using shaft encoder. There arises a new trend to apply speed sensor-less vector control., for this inverter-fed induction motor drive system. The purpose of sensor-less control is to save, cost and improve system reliability. Several sensor-less systems now under testing on the actual railway company. This paper describes the survey of the fundamental structure and feature of representative sensor-less systems mentioned above.

• 기술혁신학회지
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• 제8권3호
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• pp.1060-1086
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• 2005

In this paper, we attempt to predict the future of broadband access market where new convergence access technologies and additional services are introduced, based on consumer preferences. Conjoint analysis and mixed logit model is used for estimation, From the results, consumers value convergence access technologies such as PLC and wireless LAN, and TV-related service, However, valuation on new beneficial features of convergence access technologies is not enough to overcome their technological inferiorities in data transfer speed and quality stability at current technological stage, Additionally, consumer preferences are so heterogeneous that differentiated business strategies are required, Finally, some managerial and policy implications are presented.