• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.630-640
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• 2007

This paper presents the design of service model, transport channel, and service signaling for the Terrestrial DMB Automatic Emergency Alert Service (AEAS) Standard. The paper begins with the analysis of technical backgrounds related to the design topics. Next, the raper presents the design of service model for the AEAS. Since, unlike the regular T-DMB services, the AEAS is event-driven and common to all services, some problems have been identified to design a service model conforming to the T-DMB standard. So, the paper proposes a new concept, called the common service, and the AEAS is modeled using the common service. Next, in order to decide the transport channel for the alert information, the paper proposes to divide the alert information into the message which contains code/text-based essential information, and the supplemental multimedia information. Then, the paper tries to find the most efficient transport channels. Emergency Warning Service (EWS) which uses FIG 5/2 is selected for the delivery of the message. The paper proposes no constraints on delivery of supplemental information except that it shall use the MSC. Finally, it proposes the service signaling for the common service and transport channel. Due to the problems of conventional signaling using the MCI, it proposes a new signaling method. The paper will contribute as a guideline to the development for emergency alert service standards fur other broadcasting media.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.337-340
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• 2002

In data transmission at the digital satellite broadcasting systems, the delay and spread are caused whit receiving original signals from the transmitter in the receiver. So, there are some problems in data fast transmission. Also, transmitted signals ate received in stale of the combination of transmission delay and noise of channel. The affect of channel noise is reduced when increasing transmission power, but as signal interference due to the transmission delay and spread of channel increase in proportion to the transmission power, there is a problem in spite of increasing the transmission power. And there is the problem to add ISI(inter symbol interference) because the property of the channel is limo-varying due to relative moving in the transceiver Therefore, in this paper, a pulse shaping filter for the high-speed service in digital satellite broadcasting systems was designed and reduced the ISI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.965-972
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• 2005

We propose a new resource management scheme, Distributed Channel Allocation Protocol (DCAP), for multimedia Ad Hoc Wireless LANs (AWLANS). This scheme implements a Qualify-of-Service (QoS) providing distributed resource management on the Orthogonal Frequency Division Multiplexing-Code Division Multiple Access (OFDM-CDMA) channel architecture. According to the performance evaluation results for MPEG traffic sources, DCAP can be a good choice of resource management scheme for AWLANs supporting multimedia services on the Broadband Wireless Access(BWA)-type physical layer.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.1
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• pp.1-8
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• 2008

In the Web 2.0, besides more gaining information on the web, the number of web sites that take advantage of RSS increases explosively. Commonly each users search RSS channels through the web search engine before registering RSS channel's url to the RSS reader. Users judge whether the site is RSS channel or not and register an RSS channel's url through theirs interests. Because accomplished by users themselves, those processes conflict to user's convenience and quick consumption of information. Techniques of current search engines can't provide users with reliable RSS feed information as search results. In this paper, we analysis appropriateness of current search engines' techniques that offer users RSS feed search service and discuss their limitations. Also, we make up RSS feed database through classification of RSS tag being possible to search RSS feed information effectively and apply update rate of each RSS channel's feed to ranking algorithm providing more reliable search results.

• ETRI Journal
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• v.29 no.5
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• pp.607-613
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• 2007

Most signal-to-noise ratio (SNR) estimation techniques in digital communication channels derive the SNR estimates solely from samples of the received signal after the matched filter. They are based on symbol SNR and assume perfect synchronization and intersymbol interference (ISI)-free symbols. In severe channel distortion where ISI is significant, the performance of these estimators badly deteriorates. We propose an SNR estimator which can operate on data samples collected at the front-end of a receiver or at the input to the decision device. This will relax the restrictions over channel distortions and help extend the application of SNR estimators beyond system monitoring. The proposed estimator uses the characteristics of the second order moments of the additive white Gaussian noise digital communication channel and a linear predictor based on the modified-covariance algorithm in estimating the SNR value. The performance of the proposed technique is investigated and compared with other in-service SNR estimators in digital communication channels. The simulated performance is also compared to the Cram$\acute{e}$r-Rao bound as derived at the input of the decision circuit.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1002-1011
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• 2005

In this paper. we design and implement a bi-directional broadcasting system, so called return channel server, to allow users to participate in a broadcasting program by using a hi-directional interaction channel. To provide user participation in a program and reflect the user's opinions or responses in real time, the return channel server can be viewed as consisting of four major functional modules: a control module, network interface module, DBMS module, and real-time content authoring module. To construct a return channel server that has a service independent architecture, we designed a return channel server to include the hierarchical structure. The presented return channel server consists of two parts: an RCSAE(return channel server application environment) and RCSA(return channel server application). An RCSA is composed of an execution code and a parameter for executing the execution code. RCSA defines the procedures for providing a specific broadcasting program using the return channel server. On the other hand, an RCSAE provides the environment for the execution of RCSAS. By adopting RCSAE and RCSA, we construct the return channel server that has a service-independent architecture which are shown by the test.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.263-272
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• 2008

Recently, WiBro has been developed to efficiently support real-time broadcasting with wireless system. MBS (Multicast Broadcast Service) based on WiBro has numerous applications such as DMB. Since the current MBS uses only common channel managed by scheduling, it cannot effectively support many users at the same time. This paper proposes a new counting scheme with which the channel mode can be properly switched between common channel and dedicated channel. It thus allows efficient use of limited radio resource in WiBro for the MBS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.131-134
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• 2009

The MOST network, which is a network for vehicle infotainment network, requires efficient channel allocation to provide multimedia service effectively. Though there is a study on channel allocation according to network traffic as studies on channel allocation for MOST network, there have scarcely been studies on channel allocation according to bandwidth of multimedia for transferring. Therefore, in this paper, we propose the channel allocation method which calculates the number of channels by analyzing multimedia data for transferring and assigns the optimal number of channels for the given data. The proposed method reduces wasting of channels by optimally allocating channels and prevents initializing network due to change of Boundary Descriptor.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.121-127
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• 2023

A 500 km/h linear motor high speed terrestrial transportation service is planned to launch 2027 in Japan. In order to support 5G service in the train, the Sub-carrier spacing frequency of 30 kHz is planned to be used instead of common 15 kHz sub-carrier spacing to mitigate Doppler effect in such high-speed transportation. In addition, to increase the cell size of 5G mobile system, plural Base Station antenna will transmit the identical Down Link (DL) signal to form the expanded cell size along the train rail. In this situation, forward and backward antenna signals will be Doppler shifted by reverse direction respectively and the receiver in the train might suffer to estimate accurate Channel Transfer Function (CTF) for its demodulation. In this paper, Delay and Doppler Profiler (DDP) based Channel Estimator is proposed and it is successfully implemented in signal processing simulation system. Then the simulated performances are compared with the conventional Time domain linear interpolated estimator. According to the simulation results, QPSK modulation can be used even under severe channel condition such as 500 km/h, 2 path reverse Doppler Shift condition, although QPSK modulation can be used less than 200 km/h with conventional Channel estimator.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.304-306
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• 2004

With the developing of current multimedia broadcasting, user will be provided for lots of various content through the various channel and media. Content provider and consumer want the various service using content with the better quality which is fit to users' preference. For transmitting this content in the limited transmission channel capacity, it needs to transmit the highly compressed content. The content of 3D mesh model-based on MPEG-4 enables the various content service that provides the lower size and the resonable quality, and Personalize(Targeting) service just provide the contents that user more wants and likes. This paper presents the study on the targeting service using compression of 3D mesh model-based on MPEG-4 and the adaptation of Embedded Graphic application program using it.