• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.106-112
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• 1998

Recently, the amount of image and audio data has been increasing dramatically for high performance. According to this trend, a high-density magnetic recording system is necessitated and the tracks of magnetic tapes are getting narrower. This, in turn, requires the capstan servo system of the magnetic recording system such as DVCR to control precisely the speed and position of the capstan motor. Especially, in case of play-back, the capstan servo system should be able to position and maintain the head on the desired place of the track. To meet this requirement, digital camcorders use ATF (Automatic Track Following). In this paper, a new ATF block using discrete Fourier transform is proposed. The proposed ATF block was designed and implemented in ALTERA FPGA chips and fully tested in a real DVCR system. It is shown through experiments that the new ATF block is more cost-effective than other existing ATF blocks using digital lowpass filters. In particular, the number of logic gates can be reduced by 20% in average, compared to the existing ATF's.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.87-93
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• 2018

This Study Propose A New Approach To Impliment A Intelligent Robot Control Based on Voice Recognition For Smart Factory Automation Since human usually communicate each other by voices, it is very convenient if voice is used to command humanoid robots or the other type robot system. A lot of researches has been performed about voice recognition systems for this purpose. Hidden Markov Model is a robust statistical methodology for efficient voice recognition in noise environments. It has being tested in a wide range of applications. A prediction approach traditionally applied for the text compression and coding, Prediction by Partial Matching which is a finite-context statistical modeling technique and can predict the next characters based on the context, has shown a great potential in developing novel solutions to several language modeling problems in speech recognition. It was illustrated the reliability of voice recognition by experiments for humanoid robot with 26 joints as the purpose of application to the manufacturing process.

• Journal of Korea Multimedia Society
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• v.15 no.8
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• pp.963-976
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• 2012

'Gesture' except for voice is the most intuitive means of communication. Thus, many researches on how to control computer using gesture are in progress. User detection and tracking in these studies is one of the most important processes. Conventional 2D object detection and tracking methods are sensitive to changes in the environment or lights, and a mix of 2D and 3D information methods has the disadvantage of a lot of computational complexity. In addition, using conventional 3D information methods can not segment similar depth object. In this paper, we propose object detection and tracking method using Depth Projection Map that is the cumulative value of the depth and motion information. Simulation results show that our method is robust to changes in lighting or environment, and has faster operation speed, and can work well for detection and tracking of similar depth objects.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1493-1501
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• 1999

For the multimedia conference in various networks, international standard works make progress with H and T series. T.120 series are recommended for multipoint data conference in various networks, but its demerit is not supported with video and audio capabilities. H.32X series are recommended for videoconference in various networks. To solve these problems, the combination of H.32X and T.120 are used. But many difficulties exist for consistent control. To solve these problems, T.130, T.131 and T.132 standardizations are made progress, and these are analyzed and implemented over LAN(Local Area Network). Our system introduced in this paper is currently operated on LAN, but can be operated with mixed networks with addition of underlying network dependent protocols.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.182-189
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• 2005

In this paper, an asymmetric WDM-EPON transmission scheme is proposed to be used in a high speed access network system, which is required to implement the convergence of broadcast and communication. WDM is used for downstream transmission from OLT to access nodes, satisfying wide bandwidth requirement for broadcasting and various multimedia services. And an EPON scheme, which is cheaper than WDM, is applied to upstream transmission where less bandwidth is required. A transmission test in physical layer was performed successfully and the results are provided. If ONUs are to be used in a home gateway, its protocol should be appropriate to its traffic pattern. Voice is sensitive to a time delay while data is not. A new dynamic bandwidth assignment protocol for PON system, which can cope with various types of data in access network is proposed and its performance is analysed. A maximum cycle time is specified to achieve the QoS of signals sensitive to time delay. And a minimum window is specified to prevent the downstream control signals from uprising. It is shown by simulation that the proposed EPON protocol can provide a better performance than previous ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1046-1051
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• 1999

It is well known that Parallel Concatenated Convolutional Codes(turbo codes) has a good performance for long block sizes. This thesis has analyzed the performance of turbo code which is based on voice or control frames with short frame sizes in the future mobile communication system. Also, at the similar decoding complexity, the performance of turbo code and convolutional codes in the speech/control frames, and the applicability of this system are considered. As a result, turbo code in short frame sizes present the performance of a BER of $10^{-3}$ or more over 3 iterations in the future mobile communication system. However, at a BER of $10^{-3}$ , if the same complexity is considered, the performance of rate 1/2 turbo code with K = 5 is better than that of convolutional code with K = 9 at low $E_b/N_0$, and the performance of turbo code with K = 3 is superior to that of convolutional code with K = 7. Rate 1/3 turbo code with K = 3 and 5 have similar to performance of rate 1/2 turbo code.

• Journal of Digital Contents Society
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• v.16 no.6
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• pp.917-925
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• 2015

WebRTC is one of the most recent technologies that supports browser-to-browser for voice calling, video chat, and P2P file sharing without the need of either internal or external plugins. However, there has some limitation which lets our development deal with many problems. This research will focus just on a small field of that problem which is bandwidth. While the bandwidth for downloading and uploading is fixed by service providers, but the number of users in a certain area is increasing largely by the time. In this paper, we propose a model to overcome the limitation of the bandwidth based on fuzzy control to adjust utilized bandwidth by changing frame rate and resolution of streaming video in the client itself.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.117-124
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• 2008

In this paper, the call setup performance of the CSCF(Call Session Control function) that manages the session control in providing the IMS(IP Multimedia subsystem)-based multimedia service in the BcN(Broadband convergence Network) is analyzed. While the performance related with the call/session of the SIP-Based voice service is analysed, the study for the call recessing performance of the IMS-based multimedia service is insufficient. In this paper, as, the processing capacity and subscriber number of CSCF were changed, the call setup delay time according to the session setup procedure of IMS was measured using the M/M/1 queuing model and OPNET simulation. The experimental results show that the sudden increased delay showed up in case the session establishment requirement ratio of total users over 13% of the CSCF processing capacity. Therefore, the user number and capacity of CSCF suitable for the session establishment delay threshold can be calculated or estimated.

• Journal of IKEEE
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• v.19 no.2
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• pp.133-141
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• 2015

The IMS is an architectural control framework for delivering IP multimedia services such as voice, video, audio and data, the IMS supports not only the mobile communication system but also the existing wired and wireless network based on IP. The network that is integrated by the IMS needs policy-based network management protocol for managing the limited network resources to provide efficient multimedia service. The IMS use additional device called PDF for efficient resource management, but the PDF only uses diameter which is one of the network management protocol such as SNMP and COPS. Many devices use various protocol to manage the limited network resources. There is an algorithm using a variety of protocols such as Diameter, COPS and SNMP to handle the resources management efficiently. We also analyze the performance using the proposed algorithm in the implemented IMS environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1A
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• pp.17-24
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• 2003

Access network is one of the most critical components of telecommunication networks. Essentially it provides the final connection through to the subscriber and at the same it is usually the most expensive component in terms of capital investment and ongoing cost of maintenance and repair In recent, various access technologies with broadband have been developed and also are emerging newly Comparing fixed access networks, the concrete concept as well as the scope of mobile access networks or parts has not been defined yet although it is caused by peculiarities of mobile network with mobility-guarantee technology, use of RF resource, fixed-exchange and transport networks This article examines the characteristics and detailed functions of BTS, BSC, MSC and other components in CDMA mobile network under the IS-95 A/B and cdma 2000-1x standards comparing the ITU's access network functional model From the systematic and functional perspectives, futhermore, an alternative definition for access parts of mobile network is proposed.