• Journal of Communications and Networks
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• v.13 no.3
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• pp.277-285
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• 2011

Real-time multimedia streaming over the Internet is rapidly increasing with the popularity of user-created contents, Web 2.0 trends, and P2P (peer-to-peer) delivery support. While many homes today are broadband-enabled, the quality of experience (QoE) of a user is still limited due to frequent interruption of media playout. The vulnerability of TCP (transmission control protocol), the popular transport-layer protocol for streaming in practice, to the packet losses, retransmissions, and timeouts makes it hard to deliver a timely and persistent flow of packets for online multimedia contents. This paper presents TCP-real-time online multimedia environment (ROME), a novel transport-layer framework that allows the establishment and coordination of multiple many-to-one TCP connections. Between one client with multiple home addresses and multiple co-located or distributed servers, TCP-ROME increases the total throughput by aggregating the resources of multiple TCP connections. It also overcomes the bandwidth fluctuations of network bottlenecks by dynamically coordinating the streams of contents from multiple servers and by adapting the streaming rate of all connections to match the bandwidth requirement of the target video.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.1-12
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• 2002

In the multimedia CDMA mobile communication service, it is required to support various applications, such as voice, video, file transfer, e-mail, and Internet access, with guaranteed QoS. In the mixed traffic environment ,which consists of voice, stream data, and packet data, we analyze the network where preemptive priority is granted to delay-intolerant voice service and a buffer is offered to delay-tolerant stream data service. And, for best-effort packet data service, the access control by transmission permission probability is applied to obtain prominent throughput. To analyze the multimedia CDMA mobile communication system, we build a 2-dimensional markov chain model about prioritized-voice and stream data services and accomplish numerical analysis in combination with packet data traffic based on residual capacity equation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.26-39
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• 2007

In recent years, rate control is an important technique in real time video communication applications using H.264/AVC. Many existing rate control algorithms employ the quadratic rate-distortion model, which is determine the target bits for each P frame. In this paper, a new rate control algorithm for transmission of H.264/AVC video bit stream through CBR(Constant Bit Rate) channel is proposed. The proposed algorithm predicts an adaptive QP(Quantization Parameter) for improving video distortion, due to high motion and abruptly scene change, which target bit rate and MAD(Mean of Absolute Difference) for current frame considering image complexity variance between previous and current frames. Additionally, it uses frame skip technique to maintain bit stream within a manageable range and protect buffer from overflow or underflow. Experimental results show that the proposed method gives a quality improvement of about 0.5dB when compared to previous rate control algorithm. Also our proposed algorithm encodes the video sequences with less frame skipping compared to the existing rate control for H.264/AVC.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.41-46
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• 2011

Mobile Ad-Hoc networks (MANET) has been getting the spotlight in the area of the wireless networks because of its flexibility and salability, and developing of many applications with it. As a consequence, MANETs are required to process not only simple data traffics, but also multimedia traffics, which has some constraints on the performances. However, unlike wired-networks, the wireless networks have frequent route-disconnections due to some reasons such as channel errors and mobility. Such frequent link disconnections makes the delivery of multimedia traffics difficult. Even though there many researches on multimedia transmissions on various environments, the performances of multimedia transmissions over fading channel and mobility even using various routing protocols have not been evaluated. Therefore, this paper extensively simulates the MPEG-4 video transmission over fading channel environment with node's mobility. In addition, the performances with two routing protocols such as AODV and DSR are compared. Finally, the simulation results shows that DSR protocol has the better performances to deliver MPEG-4 traffic.

• Journal of Distribution Science
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• v.1 no.1
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• pp.1-24
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• 1999

CALS/EC is about doing business electronically. It is based on the electronic processing and transmission of data, including text, sound and video. It encompasses many diverse activities including electronic trading of goods and services, online delivery of digital content, electronic fund transfers, electronic share trading, electronic bills of lading, commercial auctions, collaborative design and engineering, online sourcing, public procuremet, direct consumer marketing, and after-sales service. It involves both products(e.g. consumer goods, specialised medical equipment) and services(e.g. information services, financial and legal services); traditional activities(e.g. healthcare, education) and new activities (e.g. virtual malls). CALS/EC will be emerging to replace and substitute the role of the conventional market. By changing and eliminating some processes of the transactions, the electronic market and the electronic commerce will redistribute the power and hence the benefits of the market activities. Traditional way of doing business may enter into the new electronic market because the role and function of trust and established reputation will be reinforced in the electronic market. The CALS/EC through the Internet has been in the spotlight in the shopping behavior of the consumers. Accordingly Corporates are trying to adapt themselves to those rapidly changing environments being affected by the Internet. Among others, particularly to be noted is the CALS/EC between corporations and consumers whose potential growth can be considered very substantial. This report, focusing on the introduction of CALS/EC for the logistics of SMEs, will allow us to prepare more efficiently for the coming 21st Century. It is obvious that CALS/EC is fast becoming the useful way of exchanging not only information but products in business between firm-to-firm and firm-to-customer.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.63-70
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• 2016

To increase throughput efficiency and improve performance, FTN(Faster Than Nyquist) method and LDPC(Low Density Parity Code) codes are employed in DVB-S3 system. In this paper, we proposed efficient turbo equalization model to minimize inter symbol interference induced by FTN transmission. This paper introduces two conventional scheme employing SIC(Successive Interference Cancellation) and BCJR equalizer. Then, we proposed new scheme to resolve problems in this two conventional scheme. To make performance improved in turbo equalization model, the outputs of LDPC and BCJR equalizer are iteratively exchange probabilistic information. In fed LDPC outputs as extrinsic informa tion of BCJR equalizer. we split LDPC output to separate bit probabilities. We compare performance of proposed scheme to that of conventional methods through using simulation in AWGN(Additive White Gaussian Noise) channel. We confirmed that performance was improved compared to conventional methods as increasing throughput parameters of FTN.

• International Commerce and Information Review
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• v.1 no.1
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• pp.179-201
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• 1999

CALS/EC is about doing business electronically. It is based on the electronic processing and transmission of data, including text, sound and video. It encompasses many diverse activities including electronic trading of goods and services, online delivery of digital content, electronic fund transfers, electronic share trading, electronic bills of lading, commercial auctions, collaborative design and engineering, online sourcing, public procuremet, direct consumer marketing, and after-sales service. It involves both products(e.g. consumer goods, specialised medical equipment) and services(e.g. information services, financial and legal services); traditional activities(e.g. healthcare, education) and new activities (e.g. virtual malls). CALS/EC will be emerging to replace and substitute the role of the conventional market. By changing and eliminating some processes of the transactions, the electronic market and the electronic commerce will redistribute the power and hence the benefits of the market activities. Traditional way of doing business may enter into the new electronic market because the role and function of trust and established reputation will be reinforced in the electronic market. The CALS/EC through the Internet has been in the spotlight in the shopping behavior of the consumers. Accordingly Corporates are trying to adapt themselves to those rapidly changing environments being affected by the Internet. Among others, particularly to be noted is the CALS/EC between corporations and consumers whose potential growth can be considered very substantial. This report, focusing on the introduction of CALS/EC for the logistics of SMEs, will allow us to prepare more efficiently for the coming 21st Century. It is obvious that CALS/EC is fast becoming the useful way of exchanging not only information but products in business between firm-to-firm and firm-to-customer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.369-390
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• 2023

Technologies for disaster management are highly sought areas for research and commercial deployment. Landslides, Flood, cyclones, earthquakes, forest fires and road/train accidents are some causes of disasters. Capturing video and accessing data in real time from the disaster site can help first responders make split second decisions which may save human lives and valuable resource destructions. In this context the communication technologies performing the task should have high bandwidth and low latency which only 5G can deliver. But unfortunately in India, deployment of the 5G mobile communication systems is yet to give a shape and again in remote areas unavailability of 4G signals is still severe. In this situation the authors have proposed, simulated and experimented a 4G-5G communication scheme where from the disaster site the signals will be transmitted by a 5G terminal to a nearby 4G-5G gateway installed in a mobile vehicle. The received 5G signal will be further relayed by the 4G-5G gateway to the fixed 4G base station for onward transmission towards the disaster management station for decision making, deployment and relief monitoring. The 4G-5G gateway acts as a relay and converter of 5G signal to 4G signal and vice versa. This relayed system can be further mounted on a vehicle mounted relay (VMR) as proposed by 3GPP in Release 18. The scheme is also in the same line of context with Verizon's, "Tactical Humanitarian Operations Response" (THOR) vehicle concept. The performance of the link is studied in different channel conditions, the throughput achieved is superb. The authors have implemented the above mentioned system towards smart campus networking and monitoring landslides activities which are common in their regions.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.317-326
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• 2010

Nowadays, transmission bandwidth for network traffic is increasing and the type is varied such as peer-to-peer (PZP), real-time video, and so on, because distributed computing environment is spread and various network-based applications are developed. However, as PZP traffic occupies much volume among Internet backbone traffics, transmission bandwidth and quality of service(QoS) of other network applications such as web, ftp, and real-time video cannot be guaranteed. In previous research, the port-based technique which checks well-known port number and the Deep Packet Inspection(DPI) technique which checks the payload of packets were suggested for solving the problem of the P2P traffics, however there were difficulties to apply those methods to detection of P2P traffics because P2P applications are not used well-known port number and payload of packets may be encrypted. A proposed algorithm for identifying P2P heavy traffics based on flow transport parameters and behavioral characteristics can solve the problem of the port-based technique and the DPI technique. The focus of this paper is to identify P2P heavy traffic flows rather than all P2P traffics. P2P traffics are consist of two steps i)searching the opposite peer which have some contents ii) downloading the contents from one or more peers. We define P2P flow patterns on these P2P applications' features and then implement the system to classify P2P heavy traffics.