• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.327-330
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• 2008

This paper shows an implementation of WLAN-based Audio/Video(A/V) system for multimedia home networks. Proposed WLAN-based A/V system can transmit multimedia data of high quality. The entire system consists of a 16-bit RISC controller, a program ROM, a SRAM, timers, an interrupt controller, a DART, GPIOs, an I2C and the OFDM modem supporting for the IEEE 802.11g standard. The simple MAC functions are implemented by firmware on an embedded 16-bit RISC controller. The OFDM modem supports a complete set of data rates up to 54Mbps. Proposed the system is implemented by an Altera FPGA EP1S60F1020C6 device, a 10-bit 2-ch DAC, a 10-bit 2-ch ADC and RF/IF chips.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.197-205
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• 2022

The Cyber Physical System(CPS) is an important concept in achieving SMSs(Smart Manufacturing Systems). Generally, CPS consists of physical and virtual elements. The former involves manufacturing devices in the field space, whereas the latter includes the technologies such as network, data collection and analysis, security, and monitoring and control technologies in the cyber space. Currently, all these elements are being integrated for achieving SMSs in which we can control and analyze various kinds of producing and diagnostic issues in the cyber space without the need for human intervention. In this study, we focus on implementing a production equipment monitoring system related to building a SMS. First, we describe the development of a fog-based gateway system that links physical manufacturing devices with virtual elements. This system also interacts with the cloud server in a multimedia network environment. Second, we explain the proposed network infrastructure to implement a monitoring system operating on a cloud server. Then, we discuss our monitoring applications, and explain the experience of how to apply the ML(Machine Learning) method for predictive diagnostics.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.402-410
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• 2022

Digital data can be manipulated easily, so information related to the timestamp is important in establishing the reliability of the data. The time values for a certain file can be extracted following the analysis of the filesystem metadata or file internals, and the information can be utilized to organize a timeline for a digital investigation. Suppose the reversal of a timestamp is found on a mobile device during this process. In this case, a more detailed analysis is required due to the possibility of anti-forensic activity, but little previous research has investigated the handling and possible manipulation of timestamps on mobile devices. Therefore, in this study, we determine how time values for multimedia files are handled according to the operating system or filesystem on mobile devices. We also discuss five types of timestamps-file created (C), last modified (M), last accessed (A), digitalized (Di), and filename (FN) of multimedia files, and experimented with their operational features across multiple devices such as smartphones and cameras.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.21-31
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• 2014

In this paper, we propose VLC(visible light communication) based multi-hop multimedia data transmission system. The main contributions and features of the proposed system are as follows. First, the contribution of this research is to develope the LED communication based multi-hop transmission network system which can transmit multimedia data(audio data, video data) with long distance. Second, the developed system has the following features: In transmitter, audio data and video data are transmitted via multi-hops using two channels. The relay in audio channel receives digital audio signal by using photo diode and then transmits the signal to receiver after error checking and amplifying. The receiver receives the encoded audio data via photo diode and then converts to analog audio signal by using decoding and amplifying. The relay in video channel receives video signal by using photo diode and then amplify the video signal using OP-AMP and then transmits the signal to receiver. The receiver amplifies the received signal from photo diode and then sends it to the monitor. The performance evaluation of the proposed system is conducted in the laboratory with fluorescent light source. The results of the performance evaluation confirm that the system can provide high quality multimedia data transmission from transmiter to receiver via multi-hop relays in a long distance while we can see there are differences in the transmitted multimedia(audio and video) quality according to the used LED colors.

• Journal of Korea Multimedia Society
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• v.18 no.3
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• pp.298-311
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• 2015

Vector data represents a map by its coordinate and Raster data represents a map by its pixel. Since these data types have very large data size, data compression procedure is a compulsory process. This paper compare the results from three different methodologies; GIS (Geographic Information System) vector map data compression using DP(Douglas-Peucker) Simplification algorithm, vector data compression based on Bin classification and the combination between two previous methods. The results shows that the combination between the two methods have the best performance among the three tested methods. The proposed method can achieve 4-9% compression ratio while the other methods show a lower performance.

• Proceedings of the Korea Database Society Conference
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• 1997.10a
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• pp.3-23
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• 1997

Internet can provide raw multimedia information; organization of information is the key challenge for the future. Keep the person in the loop, but provide tools to separate wheat from chaff.(omitted)

• Journal of the Korea Computer Graphics Society
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• v.21 no.3
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• pp.36-45
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• 2015

It is important subject of research in engineering and natural science field that creating continuing high-definition image from very large volume data. The necessity of software that helps analyze useful information in data has improved by effectively showing visual image information of high resolution data with visualization technique. In this paper, we designed multi-platform visualization system based on client-server to analyze and express earth environment data effectively constructed with observation and prediction. The visualization server comprised of cluster transfers data to clients through parallel/distributed computing, and the client is developed to be operated in various platform and visualize data. In addition, we aim user-friendly program through multi-touch, sensor and have made realistic simulation image with image-based lighting technique.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3139-3149
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• 1997

E-mail system has been widely used for information transmission. As multimedia technologies are developed, many Internet services support multimedia. E-mail system only transmits 7bit ASCII data using simple mail transfer protocol(SMTP) specified in RFC 821. E-mail system can't support the authoring and the transmission of multimedia data. In this study multimedia mail authoring system has been designed and implemented in order to provide message integration. Multimedia messages can be authored and transformed into text types with this system. Transformed messages are transmitted from sender's mail transfer agent (MTA) to receiver's MTA by means of SMTP. Messages can be authored in hypertext markup language (HTML) including text, image, audio and video. This system provides integrated messages which consist or various media. BASE64 Encoding method is used in order to transform multimedia messages into text types. Received mails are managed by multimedia user agent (MUA) which is proposed in this study. Convenience for user is improved in this system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.308-312
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• 2002

Recently, Internet is getting more popular and the usage of multimedia contents is getting more increased. Among the multimedia contents, the JPEG format is the most commonly used Image data format but the JPEG format doesn't supply cryptographic methods and access control. In this paper, a cryptographic method for cipher JPEG Image is proposed. This method can supply encryption and decryption using several algorithms such as DES to the JPEG Image data. Huffman table, which is the most important data area for JPEG data coding, is chosen as the coding data. Each method is compared to select the optimal cryptographic method in a certain environment.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.2
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• pp.213-225
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• 2003

In multimedia database system, it is very important issue how to query multimedia data and present the result of query. Also, in order to reuse the query result in other applications, multimedia database system must be considered to provide the query result which is more generalized form. In this paper, I propose a presentation model for presenting query result in multimedia database system and MMSQL based on the developed model for processing multimedia database query. This paper includes the design and implementation of MMSQL query processor. MMSQL query processor provides the presentation of query result which is SMIL (Synchronized Multimedia Integration Language) document. Therefore, MMSQL query result in this paper can be use to variant multimedia applications.