• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.05a
• /
• pp.611-613
• /
• 2021

Recently, research and development of quantum computers, which exceed the limits of classical computers, have been actively carried out in various fields. Quantum computers, which use quantum mechanics principles in a way different from the electrical signal processing of classical computers, have various quantum mechanical phenomena such as quantum superposition and quantum entanglement. It goes through a very complicated calculation process compared to the calculation of a classical computer for performing an operation using its characteristics. In order to utilize each element efficiently and accurately, it is necessary to visualize the data before driving the actual quantum computer and perform error verification, optimization, reliability, and verification. However, when visualizing all the data of various elements configured inside the quantum computer, it is difficult to intuitively grasp the necessary data, so it is necessary to visualize the data selectively. In this paper, we visualize the data of various elements that make up a quantum computer, and hierarchically visualize the internal circuit components of a quantum computer that are complicatedly configured so that the data can be observed and utilized intuitively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.11B
• /
• pp.960-968
• /
• 2006

HMIPv6 improved the handover management of basic MIPv6 by introducing the new protocol agent MAP. In this new protocol, MAP instead of the Mobile Node intercepts all packets and redirects the packets to CoA of the Mobile Node. However, this process may degrade the network performance due to the centralization phenomenon of registration occurring in the hierarchical MAP structure. ffe propose two schemes to improve real time traffic performance. First proposal is a MAP selection mettled in which MAP is selected based on traffic characteristics. And we also propose differentiated traffic processing scheme with multi-level queues when Home Agent or Correspondent Nodes process Binding Update messages. Performances of the proposed scheme are analyzed. Analysis result shows that our model has good performance in the respect of location update cost and total cost of Mobile Nodes.

• The KIPS Transactions:PartA
• /
• v.14A no.4
• /
• pp.235-244
• /
• 2007

Caching and prefetching policies have been used in most of computer systems to compensate speed differences between primary memory and secondary storage devices. In this paper, we design and implement a Flash Cache Core Module(FCCM) on the YAFFS which operates on a file system layer for NAND flash memory. The FCCM is independent of the underlying kernel in order to support its stability and compatibility. Also, we implement the Dirty-Last memory replacement technique considering the characteristics of flash memory, and the waiting queue for pages to be prefetched according to page hit. The FCCM reduced the number of I/Os and the amount of prefetched pages by maximum 55%(20% on average) and maximum 55%(24% on average), respectively, comparing with caching and prefetching policies of Linux.

• The Journal of the Korea Contents Association
• /
• v.10 no.9
• /
• pp.45-56
• /
• 2010

This paper reports a new mechanism for congestion controls. The proposed congestion detection algorithm can be provided with delay and unnecessary energy consumption. Conventional congestion control methods decide congestion by queue occupancy or mean packet arrival rate of MAC layer only, however, our method can perform precise detection by considering queue occupancy and mean packet arrival rate. In addition, the congestion avoiding method according to congestion degree and scheduling method using priority for real time packets are proposed. Finally, simulation results show that proposed congestion detection and control methods outperforms conventional scheduling schemes for wireless sensor network.

• Journal of the Korea Society for Simulation
• /
• v.19 no.4
• /
• pp.43-50
• /
• 2010

Recently, the Internet telephony has been used rather than the traditional telephony by many Internet users, with low cost. Session Initiation Protocol(SIP) is the standard of application layer protocol for establishment and disconnection of the session for Internet telephony. SIP mainly runs over the UDP for transport. So in case of the loss of the INVITE request message, the message is retransmitted by an appropriate timer for reliable transmission of the UDP message. Though the retransmission is useful for ensuring the reliability of SIP messages sent by the users, it may cause the overload traffic in the SIP proxy server. The overload in SIP proxy servers results in the loss of many input messages. This paper presents a non-linear overload control algorithm to resolve the overload condition of the server. we simulate our proposed algorithm using the network simulator ns-2. The simulation results show that the throughput of the server with the proposed algorithm have been improved about 12% compared to the existing linear control algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.2
• /
• pp.53-58
• /
• 2013

A Fat-Tree topology has multiple paths between any pair of hosts. The delay for the multiple paths with an equal number of hops depends mainly on the queuing delay. However, most of the existing load-balancing schemes do not sufficiently exploit the characteristics of Fat-Tree. In most schemes load-balancing is performed at a flow level. Packet-level load-balancing schemes usually require the availability of special transport layer protocols to address packet reordering. In this paper, we propose a new packet-level load-balancing scheme which can enhance network utilization while minimizing packet reordering in Fat-Trees. Simulation results show that the proposed scheme provides as high TCP throughput as a randomized flow-level Valiant load balancing scheme for a best case.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.10
• /
• pp.110-118
• /
• 2007

In multi-hop wireless network, multi-channel makes it possible to enhance network performance because it reduces channel interferences md contentions. Recently several schemes have been proposed in the literatures to use multi-channel. Especially, MCR(Multi channel routing protocol), which utilize hybrid interface assignment, is a prominent routing protocol. MCR uses simple way to change channel but efficiently reduce channel interferences. In this paper, we propose a load-aware channel selection algorithm called LCS that enhances the channel switching algerian used in MCR protocol. In LCS, channel of a node is assigned based on collected information about queue length of neighbors. Moreover this paper evaluates the performance of in by using simulation test and testbed demonstration. Test results show that the MCR with LCS outperforms the naive MCR.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.1
• /
• pp.129-137
• /
• 2016

Transmission Control Protocol as a transport layer protocol provides steady data transfer service. There are some serious concerns about the performance of TCP over diverse networks. The vital concern in TCP network environment is congestion which may occur due to quick transmission rates or because of large number of new connections entering the network at the same time. Size of queues in routers grows thus resulting in packet drops. Retransmission of the dropped packets, and reduced throughput can prove costly. Explicit Congestion Notification (ECN) in conjunction with Active Queue Management mechanisms (AQM) such as Random early detection (RED) is used for packet marking rather than dropping. In IP packet header ECN bits can be added as a sign of congestion thus avoiding needless packet drops. The proposed ECN and AQM mechanism can be implemented with help of ns2 simulator and the performance can be tested on different TCP variants.