• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1272-1285
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• 2018

The paper presents a novel embedded multifunctional media sever (EMMS) for mobile devices to receive various media programs. Being different from other contemporary system research, the paper mainly studies how to design a reception solution for terrestrial digital television (DTV) on mobile devices and how to enable mobile devices can receive DTV program, enjoy video-on-demand (VOD), achieve video surveillance and relay Internet video program via local Wi-Fi simultaneously. In the system design, we integrate broadcasting-terrestrial DTV tuner, streaming media re-transmission system, VOD disk, video camera and access interface to the Internet into EMMS, which can either receive terrestrial DTV radio signals and demodulate out digital transport stream (TS), or can read streaming media bit-stream from VOD disk, surveillance camera or access interface to the Internet. The experimental results show the proposed system is stable and quality-efficient. Comparing with the other systems, the proposed system has the least packet loss rate and response time.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.69-77
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• 2008

I propose adding users’Media Access Control (MAC) addresses to standard X.509 certificates to provide more secure authentication. The MAC address can be added by the issuing Certification Authority (CA) to the "extensions" section of the X.509 certificate. I demonstrate that when two users with MAC address information on their digital certificates communicate, the MAC address on the first user’s certificate can be easily verified by the second user. In this way, security can be improved without markedly degrading system performance and the level of initial trust between participants in virtual communities will be improved.

• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.277-287
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• 2006

Most of the existing broadband access networks based on DSL, cable modem, and Ethernet support the best-effort internet access service, and adopt the flat rate pricing mechanism. It is almost impossible to provide the differentiated communication services, in current broadband access networks, for the different users and/or the different application services. Currently, however, the advances in multimedia, communication, and security technologies push the interactive and/or streaming multimedia services and VPN services to be widely deployed over Internet, and they require more QoS-sensitive services than the best-effort service. Though various QoS technologies such as RSVP-based IntServ and DiffSern were already developed and under standardization in Internet world, it is impractical to replace the existing QoS-unaware access networks with the QoS-enabled ones at a time to deploy QoS-sensitive services. In this paper, after analyzing current broadband access network architectures and the status of QoS support, we propose a practical approach to support multimedia QoS in the broadband access networks. The approach will be based on the integration of the differentiated pricing and the DiffServ technology. And it will be a step-wise approach to support backward compatibility with the legacy broadband access networks as much as possible.

• Journal of Internet Computing and Services
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• v.21 no.5
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• pp.9-20
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• 2020

This study redefines the networks' connection behaviors and the terms confusion over the settlement in Netflix-SK Broadband's dispute through domestic and foreign legal references. Conflict parties, academics and the media use the terms "interconnection fee" or "Access fee" without uniformity, and in some cases mixes for strategic purposes. The use of different terms for the same phenomenon (or vice versa) has a high need for research in that it makes it difficult to reach a unified approach to the problem, to discuss it productively and rationally, and, moreover, to resolve disputes. Therefore, this study cross-referenced/analyzed terms related to network utilization and connectivity, namely "Use", "Access", "Interconnection" and thus cost-related terms as a counter-pay. In addition, it suggests that interconnection fees and access fees should be used separately, and allows them to function as a starting point in resolving future ICT sector issues. As a result of this study, the price against the network access/use between Netflix and SK Broadband is access fee or retail price, and proposes to be used uniformly in the term "interconnection fee" only for fees incurred in interconnection between ISPs that possess or operate networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.461-471
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• 2004

Recently, subscribers have strong desire to get QoS based personalized services in high-speed Internet access. Service providers have been rapidly replacing ADSL, cable broadband access networks with Metro-Ethernet based VDSL. But, it is difficult for Motto-Ethernet based broadband access networks to provide QoS based personalized services, because already deployed network elements cannot distinguish subscribers by specific traffic characteristics. In this paper, when the access network has tree topology, we show that it is possible to provide QoS for each downstream flow with only per flow traffic shaping at the edge node without QoS functions in access networks. In order to show that our suggested scheduling algorithm at the edge node can support the assured service in tree topology access networks, we evaluated its performance by simulation. The suggested scheduling algorithm can shape per-flow traffic based on the maximum bandwidth, and guarantees minimum bandwidth per flow by modifying the DRR scheduler. Simulation results show that congestion and loss in the access network elements are greatly reduced, TCP performance is highly enhanced and loss for assured CBR service flows is reduced by only shaping per-flow traffic at the edge node using our proposed scheduling algorithm.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.95-104
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• 2000

In general cases, the conventionl Internet connected to a terrestrial network is too slow to transmit large medical images. To overcome this low speed problem of the Internet, we have developed asymmetric satellite data communication system (ASDCS) as a fast satellite Internet communication method. The ASDCS uses a receive-only satellite link for dat delivery and a terrestrial network for control communication. The satellite communication link we implemented showed the very high-speed performance compared to the terrestrial link. Using ASDCS, the satellite Internet communication was 10-30 times faster than the conventional terrestrial Internet link. Also we have developed a Web-based Telemedicine system that can access every permitted server of hospital via the Internet. Java programming techniques were used to make our system and it can access and retrieve medical information and images through only public web browser such as Netscape TM without additional specific tools. To increase the transmitting speed of our Telemedicine system, JPEG method was used. In conclusion, we were able to develop a fast and public Telemedicine system using the proposed ASDCS and Web technology. ASDCS technology increased the speed of the conventional Internet and Web technology extended the scope of use for Telemedicine system from intrahospital to public use.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.597-600
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• 2003

Wireless Internet access shows an early-stage market that is entering a period of strong and sustained growth., reaching almost $40 billion in combined related equipment services by 2008 with equipment and services of nearly equal proportion. This explosive development is possible due to the continued growth of two of the most successful markets in history, the internet and mobile telephony. The number of global wireless internet users will incense from approximately 1.9million in 2001 to 1.3billion by 2006. Technological changes are the main factor in the emergence of what is being called the fourth generation of mobile communications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.233-242
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• 2009

The security of medical information need continued research about steady and flexible security model because of privacy of patient's as well as directly relation in the patient's life. In particular, u-healthcare environment is need flexible and detailed access control by variety changes of context. Control model analyzed relation of resource and authority, and analyzed authority about all accessible resource from access point using K2BASE. The context-based access control model can change flexibly authority change and role, and can obtain resource of authority granted and meaningly connected resource. As a result, this thesis can apply flexible and adaptive access control model at u-healthcare domain which context change various.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3131-3149
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• 2016

In-band Full-duplex (IBFD) wireless communication allows improved throughput for wireless networks. The current Half-duplex (HD) medium access mechanism Request to Send/Clear to Send (RTS/CTS) has been directly applied to IBFD wireless networks. However, this is only able to support a symmetric dual link, and does not provide the full advantages of IBFD. To increase network throughput in a superior way to the HD mechanism, a novel three-way handshaking access mechanism RTS/SRTS (Second Request to Send)/CTS is proposed for point to multipoint (PMP) IBFD wireless networks, which can support both symmetric dual link and asymmetric dual link communication. In this approach, IBFD wireless communication only requires one channel access for two-way simultaneous packet transmissions. We first describe the RTS/SRTS/CTS mechanism and the symmetric/asymmetric dual link transmission procedure and then provide a theoretical analysis of network throughput and delay using a Markov model. Using simulations, we demonstrate that the RTS/SRTS/CTS access mechanism shows improved performance relative to that of the RTS/CTS HD access mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.687-708
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• 2017

The machine-to-machine (M2M) communication is featured by tremendous number of devices, small data transmission, and large uplink to downlink traffic ratio. The massive access requests generated by M2M devices would result in the current medium access control (MAC) protocol in LTE/LTE-A networks suffering from physical random access channel (PRACH) overload, high signaling overhead, and resource underutilization. As such, fairness should be carefully considered when M2M traffic coexists with human-to-human (H2H) traffic. To tackle these problems, we propose an adaptive Slotted ALOHA (S-ALOHA) and time division multiple access (TDMA) hybrid protocol. In particular, the proposed hybrid protocol divides the reserved uplink resource blocks (RBs) in a transmission cycle into the S-ALOHA part for M2M traffic with small-size packets and the TDMA part for H2H traffic with large-size packets. Adaptive resource allocation and access class barring (ACB) are exploited and optimized to maximize the channel utility with fairness constraint. Moreover, an upper performance bound for the proposed hybrid protocol is provided by performing the system equilibrium analysis. Simulation results demonstrate that, compared with pure S-ALOHA and pure TDMA protocol under a target fairness constraint of 0.9, our proposed hybrid protocol can improve the capacity by at least 9.44% when ${\lambda}_1:{\lambda}_2=1:1$and by at least 20.53% when ${\lambda}_1:{\lambda}_2=10:1$, where ${\lambda}_1,{\lambda}_2$ are traffic arrival rates of M2M and H2H traffic, respectively.