• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7A
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• pp.757-767
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• 2008

Start Ongoing next generation networks are expected to be deployed over current existing networks, in the form of overlayed heterogeneous networks, in particular, in hot spot areas. Therefore, it will be necessary to develop an interworking technique such as load balancing, to achieve increased overall resource utilization in the various heterogeneous networks. In this paper, we present a new load balancing mechanism termed 'soft' load balancing where the IP(Internet Protocol) traffic of a user is divided into sub-traffic, each of which flows into a different access network. The terminology of soft load balancing involves the use of both load sharing and handover techniques. Through a numerical analysis, we obtain an optimal LBR (Load Balancing Ratio) for determining the volume of traffic delivered to each network over an overlayed multi-cell environment. Using the optimal LBR, a more reliable channel transmission can be achieved by reducing the outage probability efficiently for a given user traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.805-812
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• 2008

H.264 technology is considered as the heart of the next-generation video codec standard. Europe and other countries have actually specified H.264 technology as the video codec standard for HD broadcasting. However, due to the complexity of algorithm, it is still a difficult job to implement HD-level H.264 decoders in real-time software. In this paper, I have restricted a part of the decoding process, in order to implement an H.264 software video decoder which guarantees a real-time operation, and suggest an H.264 decoder that adaptively selects the algorithm to minimize image degradation. Performance of the suggested H.264 decoder was compared and verified through a PC simulation. As a consequence, when the suggested decoder was used in an environment where real-time decoding was difficult, it has achieved the minimal image degradation as well as real-time decoding in most cases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.454-472
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• 2013

The development of wireless network technology and the increasing use of wireless networks to mobile users with a variety of wireless network systems has arisen. Wireless sensor networks, they can be nested together, and the need to switch between the network, depending on your needs. Next Generation Wireless Networks(NGWN) gives the mobile user a wide coverage and optimized service etc. Previous hand off management protocol is not enough to secure support of the NGWN application program. Cross-layer Handoff(CLH) protocol technique has been developed to support between and inside networks of handoff management of NGWN. CLH supports mobility management in a wireless network environment and also utilizes mobility speed and handoff signaling delay information to improve the handoff performance ability. For the analysis of handoff performance ability, we analyzed sensitivity of link layer and network layer, therefore, CLH technique is suggested based on this analysis.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.20-25
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• 2014

There are several severe problems for LED device, the next generation's economy green lighting: as the temperature increases, the lamp efficiency decreases; if the temperature is over $80^{\circ}C$, the lifetime of lighting decreases; Red Shift phenomenon that wavelength of spectrum line moves toward long wavelength occurs; and optical power decreases as $T_j$ increases. Thus, Heat sink design that can minimize the heat of LED device is currently in progress. While the thermal resistance of COB Type LED was reduced by direct coupling of LED chip to the board, residential 13.5W requires Heat sink in order resolve heat issue. This study designed Heat Sink suitable for residential 13.5W COB LED down-light and selected the optimum Fin thickness through flow simulation that packaged the designed Heat Sink and 13.5W COB. And finally it analyzed and evaluated the thermal modes using contacting thermometer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.403-410
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• 2008

In this paper, we investigate the performance of MMR system in Non-transparent mode. The IEEE 802.16j MMR system has two node of operation, Single-frame (in band) and Multi-frame (out band) mode. In the analysis, we assume that channel interference between MR-BS and RS, or between RSs anywhere in the given area is ignored. The performance is presented in terms of the delay and the frame efficiency by varying number of RS and BS coverage to RS coverage ratio and the maximum coverage area of a BS by varying traffic density. Analytical results show that the Single-frame is more efficient than Multi-frame in frame efficiency and coverage extension.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.47-52
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• 2024

The effects of annealing temperature on the optical and electrical properties of BZO thin films, grown on glass substrate, have been investigated. Analysis of the XRD shows that regardless of the annealing temperature, all BZO thin films indicate the c-axis orientation. The full width of half maximum (FWHM) decreases from 1.65 to 1.07° as the annealing temperature increases from 400 to 600℃. The average transmittance in the visible light region showed a high value of 85% without significantly affecting the annealing temperature. The results of Hall effect measurements indicate that the carrier concentration and mobility increased and the resistivity decreased as the annealing temperature increased. The resistivity and the carrier concentration of the BZO thin films annealed 600℃ were 9.75×10^-2 Ω·cm and 4.21×10¹⁹ cm^-3 respectively, showing the best value. The optimization of deposition and annealing conditions will certainly make the BZO thin films promising materials for the application to the next generation of optoelectronic devices.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.561-568
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• 2006

WPS(Wearable Personal Station) for next generation PC can define as a core terminal of 'Ubiquitous Computing' that include information processing and network function and overcome spatial limitation in acquisition of new information. As a way to acquire significant dynamic gesture data of user from haptic devices, traditional gesture recognizer based on desktop-PC using wire communication module has several restrictions such as conditionality on space, complexity between transmission mediums(cable elements), limitation of motion and incommodiousness on use. Accordingly, in this paper, in order to overcome these problems, we implement hand gesture recognition system using fuzzy algorithm and neural network for Post PC(the embedded-ubiquitous environment using blue-tooth module and WPS). Also, we propose most efficient and reasonable hand gesture recognition interface for Post PC through evaluation and analysis of performance about each gesture recognition system. The proposed gesture recognition system consists of three modules: 1) gesture input module that processes motion of dynamic hand to input data 2) Relational Database Management System(hereafter, RDBMS) module to segment significant gestures from input data and 3) 2 each different recognition modulo: fuzzy max-min and neural network recognition module to recognize significant gesture of continuous / dynamic gestures. Experimental result shows the average recognition rate of 98.8% in fuzzy min-nin module and 96.7% in neural network recognition module about significantly dynamic gestures.

• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.1-10
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• 2006

It is widely accepted that the coverage with high user densities can only be achieved with small cell such as micro- and pico-cell. The smaller cell size causes frequent handovers between cells and a decrease in the permissible handover Processing delay. This may result in the handover failure. in addition to the loss of some Packets during the handover. In these cases. re-transmission is needed in order to compensate errors, which triggers a rapid degradation of throughput. In this paper, we propose a new handover scheme in the next generation mobile communication systems, in which the handover setup process is done in advance before a handover request by predicting the handover cell based on mobile terminal's current position and moving direction. Simulation is focused on the handover failure rate and Packet loss rate. The simulation results show that our proposed method provides a better performance than the conventional method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.6
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• pp.35-41
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• 2010

The ubiquitous-transportation sensor network (u-TSN) system is a next generation transportation system that provides traffic information through analysis and processing periodic information from vehicles. In this paper, we propose the adequate transmission scheme from vehicles for collecting vehicular information. The conventional scheme is transmitting each vehicle information every 0.1s. A variable transmission period scheme is proposed in this paper according to vehicle speed. The proposed and conventional schemes are compared with computer simulations.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.459-465
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• 2010

Mobile IPv6(MIPv6) features have several defects such as overloading of nodes, loss of wireless signals, packet loss, movement problem and so forth. Proxy Mobile IPv6 (PMIPv6) got over the limit of MIPv6 problems. MIPv6 features have several defects such as overloading of nodes, loss of wireless signals, packet loss, movement problem and so forth. Research on PMIPv6, which features network-based mobility is actively in progress in order to resolve these issues. PMIPv6 is emerging as a new paradigm that can overcome the limitations of the existing MIPv6. Nevertheless, such PMIPv6 also incurs problems during hand-over. While it offers a solution to node-based problems, it does, too, create long delay times during hand-over. Since MN (Mobile Node) has been sensing its own movements on MIPv6, fast handover can be done easily. However it can't apply fast handover like MIPv6, as it can't apply fast handover like MIPv6 In this paper, the author solved hand-over problem on MIPv6. MAG knows location information of MN and if MN moves into other MAG's area, Location Server gives MN information to the MAG. Therefore, this mechanism makes hand-over process easier.