• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.72-85
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• 2012

Today, although most bluetooth hands-free devices within a vehicle provide telephone service functions such as voice communication, caller id display and SMS message display and so on, they do not provide a function that displays Internet-based text data. We need to develop a scheme that displays the internet-based text data including existing hands-free function because the request for using the Internet service is increasing within a vehicle recently. The proposed bluetooth device application includes advanced function such as SNS message arrival notification, the message display function and we chose Android as the implementation mobile platform giving consideration to the fact that most SNS applications operate on Android and the platform is easily embedded into small embedded device. Smartphone or tablet PC connected with the proposed bluetooth device is an Android-based device and we designed a form of Android app for the function implementation of the devices. When the audio-text gateway app receives SNS text data, it extracts title and sender information from the message header information in a form of text data and sends them via ACL (Asynchronous Connection-Oriented) link to the bluetooth device showing the data on the screen. Android-based bluetooth devices are not possible to play voice through speaker because the bluetooth hands-free or headset profile ported within Android platform normally only includes audio gateway's function. The proposed bluetooth device application, therefore, applies the streaming scheme that sends data via ACL link instead of the way that sending them via SCO (Synchronous Connection-Oriented) link.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.4
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• pp.159-164
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• 2023

Solar energy harvesting IoT devices prioritize maximizing the utilization of collected energy due to the periodic recharging nature of solar energy, rather than minimizing energy consumption. Meanwhile, research on edge AI, which performs machine learning near the data source instead of the cloud, is actively conducted for reasons such as data confidentiality and privacy, response time, and cost. One such research area involves performing various audio AI applications using audio data collected from multiple IoT devices in an IoT edge computing environment. However, in most studies, IoT devices only perform sensing data transmission to the edge server, and all processes, including data preprocessing, are performed on the edge server. In this case, it not only leads to overload issues on the edge server but also causes network congestion by transmitting unnecessary data for learning. On the other way, if data preprocessing is delegated to each IoT device to address this issue, it leads to another problem of increased blackout time due to energy shortages in the devices. In this paper, we aim to alleviate the problem of increased blackout time in devices while mitigating issues in server-centric edge AI environments by determining where the data preprocessed based on the energy state of each IoT device. In the proposed method, IoT devices only perform the preprocessing process, which includes sound discrimination and noise removal, and transmit to the server if there is more energy available than the energy threshold required for the basic operation of the device.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.63-68
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• 2016

Audio mixer is an electronic device which performs a mixing of multiple audio signals. Digital mixer having various functions and scalability is spreaded thanks to advanced DSP and IT technology. However, digital mixer is more vulnerable to stability comparing to conventional analog mixer in the digital error or software error sense because its control is executed by SW. To solve this problem, in this paper, we propose a multi-channel digital analog hybrid mixer scheme, digital mixer error detection mechanism and malfunctioning switching technique. Also we develop the audio mixer having digital-analog hybrid structure. By simulation, we can sense the error of digital mixer except power loss in a 120ms, change into analog mixer mode automatically and provide continuous broadcasting function without mixer function loss.

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.2
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• pp.19-30
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• 2020

Purpose: The ratio of the visually impaired is gradually increasing due to various causes such as natural aging, accidents, and environmental changes. Therefore, this study has two folds. Firstly, it aims to analyze the current satisfaction level with information facilities for the visually impaired. Secondly, it aims to examine the factors affecting the satisfaction with indoor information facilities. Through this study, it helps to identify problems of information facilities for the visually impaired and it works as a practical data for further improvements. Methods: For 50 visually impaired people, a telephone survey was conducted on the satisfaction with the braille blocks, braille signboards, braille information boards with tactile map, audio guide devices, and safety egress devices. Microsoft Excel and SPSS 26.0 were used for the analysis. Results: It was confirmed that the overall satisfaction with the indoor information facilities was very low. The more the visually impaired people recognized the installation standards, and the better the maintenance was, the higher the satisfaction. In the case of braille blocks and braille signboards, the effect of information transfer on satisfaction was relatively high. In the case of audio guide device and safety egress device, the standard suitability influenced satisfaction. Implications: The low level of satisfaction with the overall information facilities can impede visually impaired people from receiving practical help through the information facilities. Factors influencing the satisfaction level of each facility were identified, which makes it possible to prepare effective improvement measures.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.73-83
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• 2014

Thanks to the development of diverse audio editing Technology, audio file can be easily revised. As a result, diverse social problems like forgery may be caused. Digital forensic technology is actively studied to solve these problems. In this paper, a hand-held device identification method, an area of digital forensic technology is proposed. It uses the noise features of devices caused by the design and the integrated circuit of each device but cannot be identified by the audience. Wiener filter is used to get the noise sounds of devices and their acoustic features are extracted via MIRtoolbox and then they are trained by multi-layer neural network. To evaluate the proposed method, we use 5-fold cross-validation for the recorded data collected from 6 mobile devices. The experiments show the performance 99.9%. We also perform some experiments to observe the noise features of mobile devices are still useful after the data are uploaded to UCC. The experiments show the performance of 99.8% for UCC data.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.2
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• pp.102-110
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• 2006

This paper explains the design and development of the stand-alone high sound quality Internet Radio system, which is aimed for a small embedded type audio device rather than a general PC type. This device is designed to work with an Internet connection. This kind of system is not standardized so far, and also the related algorithm is not open to the public. So it is necessary to analyze several receiving algorithms of current radio receivers, and develop our own hardware in order to overcome these obstacles, finally to get the high quality of sound radio. The main electronic components of this Internet Radio are TCP/IP interfaces, an audio MP3 decoder, an I/O interface, and a Flash Memory Card with advanced audio multicasting for the next-generation Internet Radio. Basic structures and implementation issues of the next-generation most-versatile digital music player, and Internet Radio receivers, are discussed.

• ETRI Journal
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• v.35 no.2
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• pp.332-335
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• 2013

In this letter, the acoustic noise due to long term evolution (LTE) user equipment (UE) is investigated with various transmitting powers of the LTE UE by using the Monte Carlo method in a practical acoustic noise experiment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.165-172
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• 2016

This paper presents an implementation of a live audio streaming system using the Raspberry Pi 3 embedded computer. This system is a live streaming system not file-based streaming. This is a push streaming system which converts the incoming analog audio signal to digital samples and broadcasts them to multiple connected users concurrently. Since the server software is developed in Java language, it can be installed on any other embedded computers without any modification. We concluded that ESCatcher can service live streaming about 60 users concurrently through calculations and experiments, And also we achieved the delay time of a little bit more than 40ms between arrival of audio source and play on the android device.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.6
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• pp.580-587
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• 2000

In this paper, we present a design method of a digital filter converting humming voice melody into MIDI data and a method of adapting it to a distributed multimedia I/O server. MuX uses device-independent DLMs(Dynamic Linking Module) for the inteliace with various I/O devices, and has wave-form audio DLM and MIDI DLM for audio interfaces. In order to expand the audio device interfacing ability of MuX system, we have designed and implemented a filter transforming human voice into MIDI messages. As the methods to input MIDI data are expanded to human voice in addition to MIDI files and MIDI instrument, someone who is not good at playing instruments can also generate the MIDI data, which enables our media interfaces to be used in various applications.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.140-145
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• 2008

Mobile device has a constraint such as a small physical display size and interaction. One of the most important issues in mobile devices is the express an identity of one's products company. It can be appeal to the user in side of consistency. Thus, we integrate and extract an identity element from user experience including, Graphical User Interface, Information Architecture and Audio User Interface. The study was conducted by a task force team with User Interface practitioners of managing divisions of each product. In this study, methods and processes that were attempted in order to establish consistency principles of user experiences, enhancing the various characteristics of each product, are described. The results and practical experiences obtained through the processes are introduced.