• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.198-201
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• 2003

Changes in internet and network environment make it possible to provide high-quality content services in real time. As demand for digital content is increased, problems related to intellectual property rights are getting more important. Streaming service like video-on-demand solved this problem by preventing content from being saved. But, as the advent of several tools able to save streamed content, the streamed content is not free from these problems any more. So, with security countermeasure like access control, new technologies to control and manage rights for content are needed. One of the solutions is DRM In this paper, we describe a DRM-based streaming service that can send the ASF stream which is the multimedia file format of Microsoft.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.314-327
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• 2009

This paper studied the relationship between the quality of perceived service and the consumer satisfaction on IPTV which is on the increase in the number of subscribers as the representative of a convergence service of the communication and broadcasting. Using the measurement tools of five factors such as the perceived service quality, the accommodation of information techniques, the consumer satisfaction, the intention of continuous use and the users' intention to recommend to others, the empirical study on IPTV users was taken. The results showed that the perceived serviced service quality, usefulness and easy access to IPTV have strong effects on the use and the users, intention to recommend to others.

• 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.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.1-7
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• 2004

In addition to wired communication technology, wireless communication technology has been driving communication revolution nowadays. Bluetooth technology carries out data/voice communication making pico-net and the various application services are supported by access network connected to public network. This paper presents educational software development of bluetooth protocol stack including HCI, L2CAP, RFCOMM, SDP and profiles including GAP, SPP, GEOP, FTP. This software which supports programming environment of these protocol monitoring and emulation is implemented basically step by step for education based on H connected to the bluetooth device through RS-232-C, UART or USB cable. Application program coded by Visual C is operated over the firmware loaded on the bluetooth device connected to the PC. Additionally ftp and chatting function are developed to enhance educational efficiency.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.512-516
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• 2006

The relations between the two countries, Korea and Japan, are growing worse because of the matter of distorting korean history, absurd remark for aggressive war, and claiming Tokto by Japan. At the point of time, I research the distorted instances of Korean history in Japanese game. The distorted instances of Korean history in game are existed in any countries' game such as China and The West; however, Japanese game takes distorted instances too far. Teenagers in the interior of a country and people from other countries easily access the distorted game because of the development of Internet and promoted cultural exchange among nations so it is necessary that systematic countermeasure should be set.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.308-317
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• 2008

The objects real time rendered in the 3D cyber space can interact with each others according to the events which are happened when satisfying some conditions. But to representing the behaviors with these interactions, too many event conditions are considered because each behavior pattern and event must be corresponded in a one-to-one ratio. It leads to problems which increase the system complexity. So, in this paper, we try to physical method based on elasticity force for representing more realistic behaviors of AI fish and apply to the deformable multi-detection sensor, so we suggest the new method which can create the various behavior patterns responding to one evasion event.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.290-299
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• 2008

We propose the query optimization technique using query classification in hybrid spatial DBMS. In our approach, user queries should to be classified into three types: memory query, disk query, and hybrid query. Specialty, In the hybrid query processing, the query predicate is divided by comparison between materialized view creating conditions and user query conditions. Then, the deductions of the classified queries' cost formula are used for the query optimization. The optimization is mainly done by the selection algorithm of the smallest cost data access path. Our approach improves the performance of hybrid spatial DBMS than traditional disk-based DBMS by $20%{\sim}50%$.

• International Journal of Contents
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• v.3 no.2
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• pp.6-17
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• 2007

Emerging modem database applications require multi-dimensional index structures to provide high performance for data retrieval. In order for a multi-dimensional index structure to be integrated into a commercial database system, efficient techniques that provide transactional access to data through this index structure are necessary. The techniques must support all degrees of isolation offered by the database system. Especially degree 3 isolation, called "no phantom read," protects search ranges from concurrent insertions and the rollbacks of deletions. In this paper, we propose a new phantom protection method for multi-dimensional index structures that uses a multi-level grid technique. The proposed mechanism is independent of the type of the multi-dimensional index structure, i.e., it can be applied to all types of index structures such as tree-based, file-based, and hash-based index structures. In addition, it has a low development cost and achieves high concurrency with a low lock overhead. It is shown through various experiments that the proposed method outperforms existing phantom protection methods for multi-dimensional index structures.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.65-70
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• 2004

The method of broadcast encryption has been applied to the transmission of digital information such as multimedia, software, and paid TV on the open network. In this broadcast encryption method, only previously authorized users can gain access to digital information. When broadcast message is transmitted, authorized users can first decode the session key using the previously given private key and get digital information using this session key. This way, users retrieve a message or a session key using the key transmitted by broadcasters. For their part, broadcasters need to generate and distribute keys. Broadcasters should also carry out efficient key renewal when users subscribe or un-subscriber. In this paper use a broadcast, and present the DRM model, using that look into the requirement about the contents and apply also the concept of a broadcast encryption. We offer the authority to copy as the number of reproduction to want to the user, and the low so that we were convenient because we used.

• ETRI Journal
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• v.39 no.2
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• pp.213-221
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• 2017

The advent of wireless access in vehicular environments (WAVE) technology has improved the intelligence of transportation systems and enabled generic traffic problems to be solved automatically. Based on the IEEE 802.11p standard for vehicle-to-anything (V2X) communications, WAVE provides wireless links with latencies less than 100 ms to vehicles operating at speeds up to 200 km/h. To date, most research has been based on field test results. In contrast, this paper presents a numerical analysis of the V2X broadcast throughput limit using a path loss model. First, the maximum throughput and minimum delay limit were obtained from the MAC frame format of IEEE 802.11p. Second, the packet error probability was derived for additive white Gaussian noise and fading channel conditions. Finally, the maximum throughput limit of the system was derived from the packet error rate using a two-ray path loss model for a typical highway topology. The throughput was analyzed for each data rate, which allowed the performance at the different data rates to be compared. The analysis method can be easily applied to different topologies by substituting an appropriate target path loss model.