• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.650-653
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• 2011

In this paper, we describe Bluetooth system and Bluetooth security. And we analyze the structure of information security and vulnerability, introduced one of Bluetooth hacking techniques. We show a demo of the attack process to inject arbitrary hands-free voice messages and save the file information, recording a conversation through hands-free device.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.1-11
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• 2003

The purpose of the present driving simulation study was to examine the effect of cellular-phone use on driving performance when required driving speeds were systematically varied(60, 80, 100, or 120km/h) while either using cellular-phones(experimental condition; Hands-Free or Hands-Held) or not(control condition). Driving performance was measured both by longitudinal vehicle control(i.e., variabilities in driving speed and headway) and lateral vehicle control(variabilities in lane position). The results can be summarized as followings: (1) The significant difference in driving speed variation between the two cellular-phone usage conditions was found only at relatively higher driving speed conditions(i.e., over 80km/h). (2) Only in the experimental condition where cellular-phone was required to be used while driving, the magnitudes of variation in driving speed, headway and lane position were gradually increased as the required driving speeds were increased(this tendency was not found in control condition). And. (3) the dependent measures of this study appeared to suggest that cellular-phone usage itself (rather than the types of cellular-phone) had significant impact on driving performance. Finally, implication and issues related to this study were discussed.

• Archives of design research
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• v.17 no.3
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• pp.313-322
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• 2004

Product design has direct effects on sales, exciting consumer's interest in purchasing. With the draft bill of Road Traffic Law passing the National Assembly, drivers have been entirely prohibited by the law from using a cell phone while driving since June 30, 2001, As a result, the demand for and the sales of hands-free Kit products for vehicles have been skyrocketing, and more and more of them have been introduced in the market and competing each other in sales. In these situations, the study attempted to present a case study showing the whole process of product design by a small company, which intended to gain an advantage over the competitors in the sector of hands-free products for vehicles with differentiated design. The product whose design development process was presented in the study has many characteristics. Among them it is the most remarkable in removing the connection between the cell phone terminal and the stationary hands-free product. The study was aimed to increase the investment value of design by helping understand that the ultimate goal of technology is commercialization and that how great the role of design is from the beginning to the final stage of product development. It also emphasized the point that one of the goals of design development should lie in providing a more accurate perception of the importance of design to the industry, by establishing a design process throughout the whole stages of product development including initiation, designing and commercialization.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.65-71
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• 2004

This paper describes a new adaptive algorithm which can reduce the required computation quantities in the adaptive filter. The proposed S-LMS algorithm uses only the signs of the normalized input signal rather than the input signals when coefficients of the filter are adapted. By doing so, there is no need for the multiplications and divisions which are mostly responsible for the computation quantities. To analyze the convergence characteristics of the proposed algorithm, the condition and speed of the convergence are derived mathematically. Also, we simulate an echo canceller adopting this algorithm and compare the performances of convergence for this algorithm with the ones for the other algorithm. As the results of simulations, it is proved that the echo canceller adopting this algorithm shows almost the same performances of convergence as the echo canceller adopting the SIA algorithm.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.419-426
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• 2017

This paper describes an acoustic echo canceller with double-talk using BSS(: Blind Signal Separation) based on the geometric concept. The acoustic echo canceller may be deteriorated or diverged during the double-talk period. So we use the blind signal separation to detect the double talking by separating the near-end speech signal from the mixed microphone signal. In the closed reverberation environment, the blind signal separation extracts the near-end signal from unknown signals with the transformation and rotation based on the geometric concept. By this method, the acoustic echo canceller operates irrespective of double-talking. We verified performances of the proposed acoustic echo canceller by computer simulations. The results show that the acoustic echo canceller with this algorithm detects the double-talk periods thoroughly, and operates stably in the normal state without diverging of coefficients after ending the double-talking.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.33-38
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• 2009

Recently most of A/V devices are being adopted hi-tech of A VRCP and changed to mobile environment. AVRCP is designed to provide a standard interface to control A/V devices, hi-fi equipment, or others to allow a single remote control or other device to control all the A/V equipment to which a user has access. It may be used in concert with A2DP or VDP. The AVRCP defines two roles, that of a controller and target device. In AVRCP, the controller translates the detected user action to the A/V control signal, and then transmits it to a remote Bluetooth enabled device. It can be small and mixed mobile devices using bluetooth technologies. The functions available for a conventional infrared remote controller can be realized in this protocol. The remote control described in this protocol is designed specifically for A/V control only. We designed new DSP using Adaptive Acoustic Echo Canceller for bluetooth hands free based this AVRCP standard specifications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.969-976
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• 2004

The wide and growing use of cellular phones has raised the question about the possible health risks associated with radio-frequency electromagnetic fields. It would be helpful for phone users to blow the exposure levels during cellular phone use. But it is very difficult to recognize the amount of exposure, because measuring accurate level of RF is a difficult matter. In this study, we developed a model to estimate the exposure level and the individual risk of exposure by utilizing the available informations that we can get. We used such parameters as usage time a day, total using period, distance between cellular phone and head, slope of cellular phone, hands-free usage, antenna pulled out or not SAR(Specific Absorption Rate) of cellular phone, and flip or folder type. We proposed a model presenting individual risk of RF exposure from level 0 to 10 by using a neural network.