• Journal of KIISE:Information Networking
• /
• v.33 no.5
• /
• pp.369-379
• /
• 2006

In recent years, there have been many researches about Ad-hoc Networks which is available to communicate freely between mobile devices by using multi-hop without any support of relay base or access point. TCP that used the most widely transport protocol in the Internet repeats packet loss and retransmission because it increases congestion window size by using reactive congestion control until packet loss occurs. As a result of this, energy of mobile device is wasted unnecessarily. In this paper, we propose TCP-New Veno in order to improve the energy efficiency of mobile device. According to the state of network, the scheme adjusts appropriate size of congestion window. Therefore, the energy efficiency of mobile device and utilization of bandwidth are improved by the scheme. From the simulation by using ns-2, we could see more improved energy efficiency with TCP-New Veno than those with TCP in Ad-hoc Networks.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4C
• /
• pp.353-364
• /
• 2002

To prevent the performance degradation of TCP due to packet loss in the smooth handoff by the route optimization extension of Mobile If protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers the packets dropped during the handoff by forwarding the buffered packets at the old base station to the mobile user. But, when the mobile user moves to a new foreign network which is connected to a congested router, the buffered packets forwarded by the old base station are dropped and the link utilization performance degraded due to increased congestion by the forwarded packets. In this paper, when the mobile user moves to a new foreign network which is connected to a congested router, Ive propose a packet forwarding control scheme required far the old base station to improve TCP performance in mobile networks. The old base station forwards or discards the buffered packets during handoff by proposed packet forwarding control scheme based on congestion states of RED(Random Early Detection) at the congested router. Simulation results slow that link utilization performance can be improved by applying proposed packet forwarding control scheme.

• The KIPS Transactions:PartC
• /
• v.9C no.2
• /
• pp.283-292
• /
• 2002

This paper develops a scheme of resource management for guaranteeing QoS of realtime traffic in wireless mobile internet environments Mobile terminal has significant impact on the QoS originating mobility provided to a real-time application. The currently proposed MRSVP is not clear the boundary of resource reservation tregion and also can give rise to signal overhead to maintain sessions. To solve above problem, we propose the new reservation protocol, mobile cluster based H-MRSVP to combine MRSVP with moving cluster concept. In this paper, we analytically design our model for guaranteeing the QoS of realtime traffic and compare the three schemes: guard channel allocation schemes, DCA and our model. The performance measures are the probabilities of new call blocking, handoff dropping, resource utilization and service completion versus the system offered Erlang load. Consequently, Simulation indicate our model is more flexible than DCA in a view pint of channel utilization and gains the advantage over guard channel scheme with respects to the mobility.

• Journal of Convergence for Information Technology
• /
• v.7 no.4
• /
• pp.83-89
• /
• 2017

This study aims to investigate the impact of a mobile-based human coaching healthcare service provided for diabetic patients by nurses on their self-management ability. This study collected data from 311 persons who were diagnosed with diabetes from all over the country, and the collected data were analyzed through SPSS Win 23. The results of the study are summarized as follows: First, it was found that the utilization of a glucose meter by the provision of the mobile-based human coaching healthcare service was men group, and there was a statistically significant difference (${\chi}^2=6.059$, p= .048*). Second, there was a positive correlation in the utilization between the glucose meter and an activity tracker band by the provision of the mobile-based human coaching healthcare service, which was statistically significant (r=.660, p< .001). Third, as a result of checking the changes of the utilization of the glucose meter by the provision of the mobile-based human coaching healthcare service, it was maintained between 79% and 41% from Week 1 through 49. In conclusion, this study partially confirmed that the mobile-based human coaching health service was easily accessible and cost-effective in enhancing the participants'self-healthcare ability.

• The Journal of Korea Robotics Society
• /
• v.1 no.1
• /
• pp.36-45
• /
• 2006

In this paper, we introduce visual contexts in terms of types and utilization methods for robust object recognition with intelligent mobile robots. One of the core technologies for intelligent robots is visual object recognition. Robust techniques are strongly required since there are many sources of visual variations such as geometric, photometric, and noise. For such requirements, we define spatial context, hierarchical context, and temporal context. According to object recognition domain, we can select such visual contexts. We also propose a unified framework which can utilize the whole contexts and validates it in real working environment. Finally, we also discuss the future research directions of object recognition technologies for intelligent robots.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.10 no.4
• /
• pp.121-127
• /
• 2011

Many peer-to-peer (p2p) systems have been studied in distributed, ubiquitous computing environments. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. Because super-nodes can share advertisements, we can guarantee physical locality utilization between a requestor and a target during any discovery process. To overcome a node failure, we propose a simple recovery mechanism. The simulation results demonstrate that MLH-Net can decrease discovery routing hops by 15% compared with JXTA and 66% compared with Chord.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.215-218
• /
• 2010

Smart Phone with domestic demand increasing rapidly, the utilization of multimedia services have become diverse. Accordingly, Smart Phone users to hack their Jail Breaking and Rooting and illegal use of the multimedia content is copyrighted. Also relevant to mobile communication terminal as a high crime, create, and the digital evidence increases the utilization of the mobile forensic evidence is required to study. In this paper, Smart Phone Copyright Violation and Forensic Apply Method research. Smart Phone Status and related violations of copyright infringement, broadcasting, film, music, e-book, etc. for each survey item, and how to apply for forensics were studied. This study investigated the development and forensic science will be able to contribute to the development.

• The KIPS Transactions:PartC
• /
• v.11C no.6 s.95
• /
• pp.863-870
• /
• 2004

UMTS(Universal Mobile Telecommunication System) is recently recognized as a standard for 3rd generation of wireless networks and DSCH(Down-link Shared Chanel) is considered as a very effective multiplexing method in UMTS. So, it is inevitable to develope an effective packet scheduling algorithms for DSCH in UMTS. This paper describes an improved packet scheduling algorithm for DSCH of UMTS. The algorithm takes consideration in channel state for each mobile terminal to maximize link utilization, delay threshold for class 3 traffic and throughput for class 4 to get long term fairness. To verify the algorithm, we programmed a simulator using PARSEC simulation tool and got some simulation results by it. The simulation results show that the algorithm has reasonable characteristics in both of link utilization and fair-ness by trade-off.

• Electronics and Telecommunications Trends
• /
• v.35 no.6
• /
• pp.129-136
• /
• 2020

Korea launched the world's first commercial 5G services in April 2019. Mobile traffic is expected to increase further with the acceleration of mobile-centric data utilization. It is one of the most important indexes of the growth of the mobile communications market, and it has a close relationship with frequency demand and supply, network management, and information communication policy. To overcome the limitations of an analytical solution due to the high complexity of the real world, this paper estimates the diffusion of 5G users using systemic thinking and the behavior of individual agents. Based on these demand forecasts, contributions to the establishment of strategic policies are suggested. For better understanding, global 5G predictions of subscribers and mobile traffic are also compared.

• Journal of Korea Multimedia Society
• /
• v.7 no.12
• /
• pp.1754-1764
• /
• 2004

Lately mobile handheld devices such as Personal Digital Assistant (PDA) and cellular phones are getting more popular for personal web surfing. However, today most mobile handheld devices have relatively poor web browsing capability due to their low performance so their users have to suffer longer communication latency than those of desktop Personal Computers (PCs). In this paper, we propose an effective pre-refresh mechanism for embedded web browser of mobile handheld devices to reduce this problem. The proposed mechanism uses the idle time to pre-refresh the expired web objects in an embedded web browser's cache memory. It increases the utilization of Central Processing Unit (CPU) power and network bandwidth during the idle time and consequently reduces the client's latency and web browsing cost. An experiment was done using a simulator designed by us to evaluate the efficacy of the proposed mechanism. The experiment result demonstrates that it has a good performance to make web surfing faster.