• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.650-654
• /
• 1995

In digital video recording, higher areal density is strongly required for realizing digital VCRs. In order to accomplish higher areal density. we have implemented a system that has a narrow track pitch and can record data of about 30 Mbps(15 Mbps per channel) with the conventional S-VHS tapes. After computer simulation using the characteristics of the experimental system, we have selected appropriate equalizer and detection method by taking into account performance and cost (including hardware complexity). As a result, the selected equalizer and detection schemes are cosine equalizer and integrated de tection, respectively. The implemented system confirms reliable operation with a symbol error rate of less than $1{\times}10^{-4}$. In this paper, We will show the performance of the implemented system together with simulation results.

• Journal of Engineering Education Research
• /
• v.23 no.6
• /
• pp.60-67
• /
• 2020

This study was conducted to understand the experiences of engineering college professors teaching classes online due to COVID-19. Instructional strategies were proposed based on these results. This study qualitatively analyzed interviews of four engineering college professors who switched from teaching classes offline to teaching them online in the first semester of 2020. The results showed that the professors had difficulties in creating video content, interacting with students, and conducting online assessments. The results also showed that the professors had difficulties in switching to online teaching. This study was significant in that it produced empirical data about online teaching based on the experiences of engineering college professors teaching classes online.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.4
• /
• pp.381-388
• /
• 2015

In this paper, a wireless video streaming system is designed and implemented for TV white space applications. It consists of a RF transceiver module, a digital modem, a camera, and a LCD screen. A VGA resolution video is captured by a camera, modulated by modem, and transmitted by RF transceiver module, and finally displayed at a destination 2.6-inch LCD screen. The RF transceiver is based on direct-conversion architecture. Image leakage is improved by low pass filtering LO, which successfully covers the TVWS. Also, DC offset problem is solved by current steering techniques which control common mode level at DAC output node. The output power of the transmitter and the minimum sensitivity of the receiver is +10 dBm and -82 dBm, respectively. The channel bandwidth is tunable among 6, 7 and 8 MHz according to regulations and standards. Digital modem is realized in Kintex-7 FPGA. Data rate is 9 Mbps based on QPSK and 512ch OFDM. A VGA video is successfully streamed through the air by using the developed TV white-space RF communication module.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.3
• /
• pp.497-502
• /
• 2018

An analog to digital converter(: ADC) has been designed to extract video signals of marine X-band radar and convert to digital signals in order to produce rainfall information. X-band weather radars are suitable for high temporal-spatial resolution observations of rainfall over local ranges but they are very expensive and require professional management. The marine radars with 10-2 cost facilitate data collection and management as well as economic benefits. To validate the usefulness of the developed ADC, comparative observations were made with weather radar for short term precipitation cases. The rainfall distribution of marine radar observations are consistent with that of weather radar within a radius of 15 km. This demonstrates the usability of marine radar for rainfall observations.

• Journal of Korea Society of Industrial Information Systems
• /
• v.8 no.2
• /
• pp.7-13
• /
• 2003

The Internet presents a unique platform for disseminating digital content such as music, video, games, software, text, business and proprietary corporate information. It promises ubiquitous access, while at the same time fundamentally challenging the traditional rules of ownership and distribution of content. In such environment, safe protection and proper delivery of digital content would be a crucial requirement toward a new e-business model. Research on the Digital Rights Management (DRM) focuses on filling this functional vacancy of the market transition by providing a more viable business model based. XrML(eXtensible Rights Markup Language) provides a universal tool for specification of rights, fees, and issuing conditions(licenses) associated with the use and protection of digital content. ContentGuard has developed XrML to unify the Digital Rights Management(DRM) specifications and encourage interoperability. It seems that all working groups of DRM agree to use XrMl for their right description language.

• Journal of Broadcast Engineering
• /
• v.8 no.4
• /
• pp.410-426
• /
• 2003

MPEG-21 defines a digital item as an atomic unit lot creation, delivery and consumption in order to provide an integrated multimedia framework in networked environments. It is expected that MPEG-21 standardization makes it Possible for users to universally access user's preferred contents in their own way they want. In order to achieve this goal, MPEG-21 has standardized the specifications for the Digital Item Declaration (DID). Digital Identification (DII), Rights Expression Language (REL), Right Data Dictionary (RDD) and Digital Item Adaptation (DIA), and is standardizing the specifications for the Digital Item Processing (DIP), Persistent Association Technology (PAT) and Intellectual Property Management and Protection (IPMP) tot transparent and secured usage of multimedia. In this paper, we design an MPEG-21 terminal architecture based one the MPEG-21 standard with DID, DIA and DIP, and implement with the MPEG-21 terminal. We make a video summarization service scenario in order to validate ow proposed MPEG-21 terminal for the feasibility to of DID, DIA and DIP. Then we present a series of experimental results that digital items are processed as a specific form after adaptation fit for the characteristics of MPEG-21 terminal and are consumed with interoperability based on a PC and a PDA platform. It is believed that this paper has n important significance in the sense that we, for the first time, implement an MPEG-21 terminal which allows for a video summarization service application in an interoperable way for digital item adaptation and processing nth experimental results.

• Journal of KIISE:Databases
• /
• v.37 no.3
• /
• pp.127-136
• /
• 2010

With rapid growth of information and computer communication technologies, the numbers of digital documents including multimedia data have been recently exploded. In particular, news video database and news video mining have became the subject of extensive research, to develop effective and efficient tools for manipulation and analysis of news videos, because of their information richness. However, many research focus on browsing, retrieval and summarization of news videos. Up to date, it is a relatively early state to discover and to analyse the plentiful latent semantic knowledge from news videos. In this paper, we propose the news video mining system based on multi-modal approach and text mining, which uses the visual-textual information of news video clips and their scripts. The proposed system systematically constructs a taxonomy of news video stories in automatic manner with hierarchical clustering algorithm which is one of text mining methods. Then, it multilaterally analyzes the topics of news video stories by means of time-cluster trend graph, weighted cluster growth index, and network analysis. To clarify the validity of our approach, we analyzed the news videos on "The Second Summit of South and North Korea in 2007".

• Journal of Korean Institute of Industrial Engineers
• /
• v.8 no.1
• /
• pp.13-21
• /
• 1982

Experiments on the eye movement behavior were performed using Vidicon Eye Camera. Factorial design ( $3{\times}3$) was used to evaluate the validity of the eye movement as a performance measure in vigilance task. Eye movement data were recorded in video tapes, then the data were converted to digital signals, which were reduced to quantitative fixation and saccadic movement data by a microcomputer. To compare with existing vigilance performance measures, response time and the number of false alarms were also recorded. The results showed that the saccadic movement is a good measure of the performance in vigilance task : 1. Both the response time and the saccadic movement increased significantly during the initial two time blocks. 2. High correlations were shown between the response time and the saccadic movement. 3. The locational uncertainty affects the saccadic movement, the number of fixations, the response time but doesn't affect the duration of eye fixations.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.3
• /
• pp.47-54
• /
• 1996

In this paper we propose a new timing recovery method by means of utilizing service data filling rate instead of timing information of transmitter. A proposed algorithm controls the phase locked loop in the opposite direction ot data filling rate of FIFO in receiver, and it is based on the fact that average of cell jitters is zero. The proposed method is simple compared with timing information method of transmitter. It can be utilized for timing recovery in synchronous digital hierarchy as well as in plesiochronous digial hierarchy without common reference clocks in end-to-end erminals. We implement the interactive video communication system and test the proposed algorithm. As a result, we hav econfirmed that it yields good perfomrnces in terms of jitters characteristics and hardware complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.4 no.5
• /
• pp.925-938
• /
• 2010

Depending on network conditions, a communication network could be overloaded when media are transmitted. Research has been carried out to lessen network overloading, such as by filtering, load distribution, frame dropping, and other methods. Among these methods, one of the most effective is frame dropping, which reduces specified video frames for bandwidth diminution. In frame dropping, B-frames are dropped and then I- and P-frames are dropped, based on the dependency among the frames. This paper proposes a scheme for protecting copyrights by encryption, when frame dropping is applied to reduce the bandwidth of media based on the MPEG-4 file format. We designed two kinds of frame dropping: the first stores and then sends the dropped files and the other drops frames in real time when transmitting. We designed three kinds of encryption methods using the DES algorithm to encrypt MPEG-4 data: macro block encryption in I-VOP, macro block and motion vector encryption in P-VOP, and macro block and motion vector encryption in I-, P-VOP. Based on these three methods, we implemented a digital rights management solution for MPEG-4 data streaming. We compared the results of dropping, encryption, decryption, and the quality of the video sequences to select an optimal method, and found that there was no noticeable difference between the video sequences recovered after frame dropping and the ones recovered without frame dropping. The best performance in the encryption and decryption of frames was obtained when we applied the macro block and motion vector encryption in I-, P-VOP.