• Journal of the Korea Society for Simulation
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• v.6 no.2
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• pp.45-57
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• 1997

MAC (media access control) bridge is used to interconnect separate LANs and to relay frames between the BLANs (bridged LANs). Bridge architecture consists of MAC entity, MAC relay entity and bridge protocol entity protocol entity and performs learning, filtering and forwarding functions using filtering database. In this paper, we simulate these functions of bridge and the STP (spanning tree protocol). The STP derives an active topology from an arbitrarily connected BLAN. Our simulation model assumes a BLAN consisted of three bridge forming a closed loop. In order to remove the loop, each bridge process exchanges configruation BPDU (bridge protocol data unit0 with other bridge processes connected to the bridge itself. To simulate the communication between bridges, we implement the IPC (inter-process communication) server using message queues. Our simulation results show that the assumed BLAN contains no closed loop and then there is no alternative route and no unnecessary traffic.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.209-214
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• 2007

In this paper, we proposed a new MANET (Mobile Ad hoc Networks) technology of routing protocol. The MANET has a mobility formation of mobile nodes in the wireless networks. Wireless network have two types architecture: the Tree based multicast and shared tree based. The two kind's architecture of general wireless networks have difficult to solve the problems existing in the network, such as connectivity, safety, and reliability. For this purpose, as using that ADDMRP (Ad hoc network Doppler effect-based for Dynamic Multicast Routing Protocol), this study gives the following suggestion for new topology through network durability and Omni-directional information. The proposed architectures have considered the mobility location, mobility time, density, velocity and simultaneous using node by Doppler effects and improved the performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1514-1523
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• 2009

It is well known that the current wireless sensor networks addressing methods do not work efficiently in networks more than a few hundred nodes. A standard protocol in ZigBee-Standard feature in ZigBee 2007 gives balanced tree based address assignment method with distributed manner. However, it was limited to cover less than hundreds of sensor nodes due to the wasteful use of available address space, because composed sensor networks usually make an unbalanced tree topology in the real deployment. In this paper, we proposed the hierarchical cluster tree based address assignment method to support large and scalable networks. This method provides unique address for each node with distributed manner and supports hierarchical cluster tree on-demand. Simulation results show that the proposed method reduces orphan nodes due to the address exhaustion and supports larger network with limited address space compared with the ZigBee distributed address assignment method defined in ZigBee-Standard feature in ZigBee 2007.

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

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.994-1003
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• 2009

For Automatic Meter Reading System, good topology of check machines, concentrators, and repeaters in client field is important. Steiner Minimum Tree is a minimum cost tree connecting all given nodes with introducing Steiner points. In this paper, an efficient mechanism allocating and connecting check machines, concentrators and repeaters which are essential elements in automatic meter reading system is proposed, which conducts repeated applications of building approximate Minimum Steiner Trees. In the mechanism, input nodes and Steiner points might correspond to check machine, concentrators or repeaters and edges might do to the connections between them. Therefore, through suitable conversions and processes of them, an efficient network for automatic meter reading system with both wired and wireless communication techniques could be constructed. In our experiment, for 1000 input nodes and 200 max connections per node, the proposed mechanism shortened the length of produced network by 19.1% comparing with the length of Minimum Spanning Tree built by Prim's algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.714-727
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• 2015

The hierarchical structure in networks is widely applied in many practical scenarios especially in some emergency cases. In this paper, we focus on a tree network with and without packet loss where one source sends data to n destinations, through m relay nodes employing random linear network coding (RLNC) over a Galois field in parallel transmission systems. We derive closed-form probability expressions of successful decoding at a destination node and at all destination nodes in this multicast scenario. For the convenience of computing, we also propose an upper bound for the failure probability. We then investigate the impact of the major parameters, i.e., the size of finite fields, the number of internal nodes, the number of sink nodes and the channel failure probability, on the decoding performance with simulation results. In addition, numerical results show that, under a fixed exact decoding probability, the required field size can be minimized. When failure decoding probabilities are given, the operation is simple and its complexity is low in a small finite field.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.760-766
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• 2012

In this paper, we propose an efficient flooding process on link-state routing protocol. It is possible to exchange information using typical link-state routing protocol; for example, OSPF(Open Short Path First) or IS-IS(Intermediate system routing protocol) that floods LSA between nodes when the network topology change occurs. However, while the scale of network is getting bigger, it affects the network extensibility because of the unnecessary LSA that causes the increasing utilization of CPU, memory and bandwidth. An existing algorithm based on the Minimum spanning tree has both network instability and inefficient flooding problem. So, we propose algorithm for efficient flooding while maintaining network stability. The simulation results show that the flooding of proposed algorithm is more efficient than existing algorithm.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.1
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• pp.27-34
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• 2005

In this paper, we propose the Q-edge labeling method related to the graph embedding problem in binomial trees. This result is able to design a new reliable interconnection networks with maximum connectivity using Q-edge labels as jump sequence of circulant graph. The circulant graph is a generalization of Harary graph which is a solution of the optimal problem to design a maximum connectivity graph consists of n vertices End e edgies. And this topology has optimal broadcasting because of having binomial trees as spanning tree.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.57-64
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• 2005

A Piconet consists of Master device and several Slave devices. Master and Slave devices are transmitted using TDD (Time Duplex Oivision) in a Piconet. A Scattemet constructed by several Piconets communicates by a Piconet. Bluetooth Specification defines the meaning of a Scatternet. But the formation and scheduling method is not defined. For the efficient formation of a Scatternet, the preceding research proposes a tree-shape topology Scatternet. But this research passes over the characteristic of Bluetooth transmission carried out by a Piconet in the Scattemet. So this Paper proposes a efficient throughput tree formation Scatternet algorithm To improve the throughput of a Scatternet, this paper proposes a tree tolopology that guarantees the efficient throughput of a Piconet

• International Journal of Computer Science & Network Security
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• v.23 no.4
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• pp.156-165
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• 2023

IEEE 802.15.4e-TSCH is recognized as a wireless industrial sensor network standard used in IoT systems. To ensure both power savings and reliable communications, the TSCH standard uses techniques including channel hopping and bandwidth reserve. In TSCH mode, scheduling is crucial because it allows sensor nodes to select when data should be delivered or received. Because a wide range of applications may necessitate energy economy and transmission dependability, we present a distributed approach that uses a cluster tree topology to forecast scheduling requirements for the following slotframe, concentrating on the Poisson model. The proposed Optimized Minimal Scheduling Function (OMSF) is interested in the details of the scheduling time intervals, something that was not supported by the Minimal Scheduling Function (MSF) proposed by the 6TSCH group. Our contribution helps to deduce the number of cells needed in the following slotframe by reducing the number of negotiation operations between the pairs of nodes in each cluster to settle on a schedule. As a result, the cluster tree network's error rate, traffic load, latency, and queue size have all decreased.