• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.707-710
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• 2005

In this paper, we propose a new communication network for on-chip communication. The network is based on a direct sequence code division multiple access (DS-CDMA) technique. The new communication network is suitable for a parallel processing system and also drastically reduces the I/O pin count. Our network architecture is mainly divided into a CDMA-based network interface (CNI), a communication channel, a synchronizer. The network includes a reverse communication channel for reducing latency. The network decouples computation task from communication task by the CNI. An extreme truncation is considered to simplify the communication link. For the scalability of the network, we use a PN-code reuse method and a hierarchical structure. The network elements have a modular architecture. The communication network is done using fully synthesizable Verilog HDL to enhance the portability between process technologies.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.723-733
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• 2012

In wireless ad hoc networks, packet loss and latency are frequently occurred by movement of node. As the number of transmission hops increases in these networks, the throughput is increasingly deteriorated. In this paper, we design the wireless ad hoc network system based on IEEE 802.16j MMR (Mobile Multi-hop Relay), which improves the network performance. Our wireless ad hoc network system used adaptively the nearest BS and Farthest BS scheduling algorithms for efficient data transmission and chose the optimal path that minimize data loss and latency. In order to evaluate performance of the wireless ad hoc network system based on IEEE 802.16j MMR, we used the LWX (Light Wimax) model of NS-2 simulator. Through the simulation, we analyzed the network performance for various scenarios.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.2
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• pp.57-62
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• 2014

In order to provide real-time multimedia streaming service, a lot of system resources and network bandwidth required. Thus each computer is any computer other equivalent has the ability to act as a client and a server Peer-to-Peer(P2P) architecture with much interest. In this paper, techniques of P2P content that requires a user to efficiently retrieve the desired time in the streaming service have placed the focus of the research techniques. In a number present in the P2P contents, the user requests to find out the desired amount of time the content streaming services in order to provide seamless lookup latency contents search algorithm to minimize the study. P2P based smart network system and the structure of the super-node and the peer node is composed of super-gateway. Smart network system architecture proposed by performing a content search algorithm. The user requests a desired content, the service can be retrieved within the provided the flexibility.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.404-407
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• 2014

Delay Tolerant Network (DTN) is a networking architecture that is designed to solve network problem in unstable and stressed environments using the Store-Carry-Forward method. Different form general networks, DTN does not guarantee the end-to-end connectivity, it is hard for the exiting TCP/IP based protocols to normally work due to the characteristic such as large latency and unstable link connectivity. And the condition that send massage without the information of the destination occurs frequently. Thus, suitable routing protocols for DTN are required and being researched. In this paper, we propose a novel routing protocol for DTN utilizing epidemic and prediction based algorithm to prevent the defect of previously DTN routing protocols such as the absence of the holistic view of the network. Proposed algorithm predicted destination using the mobility information recorded in neighbor node's history and utilize epidemic based algorithm when occurred condition without destination's information. This algorithm is enhanced in terms of delivery ratio, decreases latency and overhead in sparse network such as DTN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2401-2409
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• 2015

This paper proposes the improved handoff mechanism for IEEE 802.11 wireless LANs. When a wireless mobile node moves out of the coverage of its currently associated AP(Access Point) and needs to be re-associated with a new AP, a handoff procedure is initiated. Channel scanning process during a handoff procedure occupies over 90% of total handoff latency. Long latency leads to many packet losses and service discontinuity, which degrades wireless network performance. This paper describes about the new mechanism to improve handoff performance by skipping channel scanning during a handoff procedure. In oerder for that, acquires neighboring AP information such as its address, location, channel number in use, the number of associated nodes before handoff, and delivers the information to its associated mobile nodes. The mobile nodes can reduce handoff latency and perform more exact handoff using the delivered AP information. We have conducted simulations to analyze our proposal's performance and confirmed that handoff latency and the number of handoff occurrences are decreased.

• Journal of Digital Contents Society
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• v.10 no.4
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• pp.501-507
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• 2009

On intranet system, it is essential element for providing information to decrease response time. To realize this efficiencies of response time of the network, a lot of research have been conducted. The purpose of the research and implementation is to shorten the response time of information system. We can realize final goal of information system through fast response time. This final goal of information system is to secure the performance efeciency within the required time. In order to acquire the method of warranty of fast response time, the efficient measurement method is essential. This research suggests a latency test techniques being used on infrastructure system and also offers a response time measurement methodology. Methodology proposed in this research has proven that it is possible to measure response time through the scheduled method. Also it is possible to develop a enhanced networking capabilities, and information system capabilities for the development of information system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.193-198
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• 2016

For environmental monitoring and risk identification of industrial plants, several monitoring systems using Wireless Sensor Networks (WSNs) have been developed. In this paper, we propose a dynamic duty cycle adjustment mechanism for reduced latency in industrial plants. The proposed method adjusts the duty cycle among predefined risk groups depending on the urgency of sensed data values. To demonstrate its efficacy, we analyze the expected transmission latency model and then discuss the characteristics in detail. We show that the proposed dynamic duty cycle mechanism is a more effective than a periodic mechanism by analyzing the expected latency of them in industrial plants where there are various types of sensory data with different levels of reliability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.77-87
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• 2017

Even though current LTE/LTE-A mobile networks provide enough high data rate and low latency to support conventional wireless services, to support ultra-low delay services, such as virtual reality and remote control, in the next generation mobile communication network, it is required to provide very low delay about several ms. However, in the uplink transmission of the LTE/LTE-A system, the process of scheduling grant is required to obtain uplink resources for uplink transmission from the eNB. The process of granting uplink resources from eNB brings additional fixed latency, which is one of the critical obstacles to achieve low delay in uplink transmissions. Thus, in this paper, we propose a novel uplink transmission scheme called Cut-in uplink transmission, to reduce uplink latency. We provide the performance of the proposed uplink transmission scheme through simulations and show the proposed uplink transmission scheme provides lower uplink transmission delay than conventional uplink transmission scheme in LTE/LTE-A mobile networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.277-284
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• 2009

With significant development in wireless communication technologies, the needs to handover from one network to another have grown dramatically. Recently IETF developed MIPv6 and FMIPv6 which are used to handover between different access networks. These handover mechanisms have some known weaknesses. MIPv6 can not serve time-critical application because it causes long handover latency and packet loss. By these reasons, MIPv6 does not guarantee session continuity. FMIPv6 uses handover preparation phase to reduce DAD latency. However FMIPv66 still suffers from long handover latency, because it must perform binding update at the end of handover procedure. In this paper we propose new handover mechanism FMIPv6-PBU which eliminates binding update latency. The proposed mechanism has compatability with lagacy FMIPv6. In this paper propose FMIPv6-PBU handover procedure and explain its procedures and evaluate it with MIPv6 and FMIPv6.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1387-1390
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• 2008

In a wireless network, handover latency is very important in supporting user mobility with the required quality of service (QoS). In view of this many schemes have been developed which aim to reduce the handover latency. The Hierarchical Mobile IPv6 (HMIPv6) approach is one such scheme which reduces the high handover latency that arises when mobile nodes perform frequent handover in Mobile IPv6 wireless networks. Although HMIPv6 reduces handoff latency, failures in the mobility anchor point (MAP) results in severe disruption or total disconnection that can seriously affect user satisfaction in ongoing sessions between the mobile and its correspondent nodes. HMIPv6 can avoid this situation by using more than one mobility anchor point for each link. In [3], an improved Robust Hierarchical Mobile IPv6 (RH-MIPv6) scheme is presented which enhances the HMIPv6 method by providing a fault-tolerant mobile service using two different MAPs (Primary and Secondary). It has been shown that the RH-MIPv6 scheme can achieve approximately 60% faster recovery times compared with the standard HMIPv6 approach. However, if mobile nodes perform frequent handover in RH-MIPv6, these changes incur a high communication overhead which is configured by two local binding update units (LBUs) as to two MAPs. To reduce this communication overhead, a new cost-reduced binding update scheme is proposed here, which reduces the communication overhead compared to previous schemes, by using an increased number of MAP switches. Using this new proposed method, it is shown that there is a 19.6% performance improvement in terms of the total handover latency.