• Journal of the Korea Society for Simulation
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• v.13 no.4
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• pp.55-69
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• 2004

In MANET(Mobile Ad-hoc Network), unlike in wired networks, a path configuration should be in advance of data transmission along a routing path. Frequent movement of mobile nodes, however, makes it difficult to maintain the configured path and requires re-configuration of the path very often. It may also leads to serious problems such as deterioration of QoS in mobile ad-hoc networks. In this paper, we proposed a Reactive Routing Keyword (RRK) routing procedure to solve those problems. Firstly, we noticed it is possible in RRK routing to assign multiple routing paths to the destination node. We applied this feature into active networks and SNMP information based routing by storing unique keywords in cache of mobile nodes corresponding to present and candidate routings in a path configuration procedure. It was shown that the deterioration of QoS which may observed in Dynamic Source Routing(DSR) protocol was greatly mitigated by using the proposed routing technique.

• Journal of Information Processing Systems
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• v.13 no.1
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• pp.104-113
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• 2017

In this paper, we present an approach to transmit data from the source to the destination through a minimal path (least-cost path) in a computer network of n nodes. The motivation behind our approach is to address the problem of finding a minimal path between the source and destination. From the work we have studied, we found that a Steiner tree with bounded Steiner vertices offers a good solution. A novel algorithm to construct a Steiner tree with vertices and bounded Steiner vertices is proposed in this paper. The algorithm finds a path from each source to each destination at a minimum cost and minimum number of Steiner vertices. We propose both the sequential and parallel versions. We also conducted a comparative study of sequential and parallel versions based on time complexity, which proved that parallel implementation is more efficient than sequential.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1371-1379
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• 2009

In this paper, we propose a new multi-path routing protocol to provide reliable and stable data transmission in MANET that is composed of high-mobility nodes. The new multi-path routing establishes the main route by the mechanism based on AODV, and then finds the backup route that node-disjoint from the main route by making add nodes in the main route not participate in it. The data transmission starts immediately after finding the main route. And the backup route search process is taking place while data is transmitted to reduce the transmission delay. When either of the main route or the backup route is broken, data is transmitted continuously through the other route and the broken route is recovered to node-disjoint route by the route maintenance process. The result of the simulation based on the Qualnet simulator shows that the backup route exists 62.5% of the time when the main route is broken. And proposed routing protocol improved the packet transmission rate by 2~3% and reduced the end-to-end delay by 10% compared with AODV and AODV-Local Repair.

• Journal of Communications and Networks
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• v.8 no.2
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• pp.228-233
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• 2006

Survivability is a very important requirement for the deployment of broadband networks because out of service links can affect volumes of traffic even if it is a very short time. And the data paths of broadband networks, which are critical for traffic engineering, are always necessary to be well protected. The procedure of protection or restoration for a path is initiated when failure is detected within the working path. In order to minimize the influence on transmission quality caused by the failure of links and to provide a definite time for the recovery from the failure, the protection switching time (PST) should be carefully considered in the path arrangement. Several researches have been devoted to construct the protection and restoration schemes of data paths over dense wavelength division multiplexing (DWDM) networks, however, there was rare research on the design of data paths with guaranteed protection switching time. In this paper, the PST-guaranteed scheme, which is based on the concept of short leap shared protection (SLSP), for the arrangement of data paths in DWDM networks is proposed. The proposed scheme provides an efficient procedure to determine a just-enough PST-guaranteed backup paths for a working path. In addition to selecting the PST-guaranteed path, the network cost is also considered in a heuristic manner. The experimental results demonstrate that the paths arranged by the proposed scheme can fully meet the desired PST and the required cost of the selected path is competitive with which of the shared path scheme.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.47-54
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• 2013

In this paper, the structural design of optical Internet is analyzed and by using UNI (User Network Interface) signaling protocol an optical transmission experiment was performed. The hierarchical structure of the basic optical Internet consists of the backbone network, the service network and the access network. The necessary functions for each layer were described as follows: Control structure of the optical transport layer, network operation and management structure, internetworking technology of sub networks, routing and signaling technology. By using UNI signaling protocol from OIF (Optical Internetworking Forum), the optical transmission in the proposed structure of the optical Internet network was experimented. By the traffic generation of LSP (Label Switched Path) data packets along the route-configuration was delivered to UNI. Finally, by showing the value of TCP (Transmission Control Protocol) packets the optical transmission was completely and successfully demonstrated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.14-21
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• 1995

General Mechanical Structures have various and complex vibration transmission paths. In order to identify the mechanism of vibration transmission. The correct estimation of exciation forces and the exact modeling of transmission paths are required. In this paper, vector synthesis technique is employed to identify the characteristics of vibration input and it's transmission to body structure for the mounting system of a compressor in a refrigerator. Vibration reduction efficiency of each transmission path is evaluated by comparing individual vector components obtained before and after the paths from experimental research. The degree of effect is used to estimate the contribution of vibration input components to total output. And this paper presents a new technique based on simulation studies using vector synthesis dragram, by which the effects of change of the magnitude and phase of transmission paths can be predicted.

• ETRI Journal
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• v.43 no.1
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• pp.133-140
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• 2021

Herein, we present a compact transversal bandpass filter (BPF) with an extremely wide upper stopband and multiple transmission zeros (TZ). Three signal transmission paths with shorted stubs and open-coupled lines allow signal transmission from input port to output port. Two resonant modes can be excited simultaneously and managed easily for bandpass response. Eleven TZs are achieved via transmission path cancelation; an extremely wide upper stopband with an attenuation level better than -12 dB is achieved up to 11.7 f0, where f0 is the center frequency (CF). In addition, bandwidth and CF can be controlled by adjusting electrical lengths. For proof of concept, a wideband BPF centered at 1.04 GHz with 3 dB fractional bandwidths of 49.2% was designed, fabricated, and evaluated. The overall circuit measures 0.045λg × 0.117λg; good agreement was observed between the measured and simulated results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.754-762
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• 2021

Seamless wireless communication network access technology enables users to guarantee service continuity. Hence, it is necessary for disaster situations in which network service may be interrupted. The Multi-path router is a technology to improve network stability and strengthen field operability, particularly in a disaster environment where network failure can occur by providing high-performance data transmission using multi-communication networks and network security by VPN-based wireless IP. In this paper, a prototype system for an MPR-based wireless communication network was proposed to improve the operation performance for disaster field investigation applications. A comparative experiment was performed on various data transmission performances with the existing single wireless communication network. In addition, another experiment was conducted by measuring the data packet transmission and receiving performance in the existing/new wireless communication system first and then assessing the UDP transmission performance in a single router environment to understand the transmission capability of the new MPR. The experimental results showed that the sending and receiving performance was improved by approximately double that of the existing single wireless communication system. The proposed prototype system is expected to allow users to share and disseminate collected on-site data more quickly and efficiently during a disaster site investigation.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.131-140
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• 2008

In this paper, we present a data dissemination protocol that guarantees energy-efficient data transmission and maximizes network lifetime. SPMS that outperforms the well-known protocol SPIN uses the shortest path to minimize the energy consumption. However, since it repeatedly uses the same path, maximizing the network lifetime is impossible. In this paper, we propose a protocol for data dissemination called the protocol Considering Between Energy and Distance (ConBED). It solves the network lifetime problem using the residual energy and the distance between nodes to determine a path for data dissemination. The simulation results show that ConBED guarantees energy-efficient transmission and increases the network lifetime by approximately 69% than that of SPMS.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.119-124
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• 2021

Elastic Optical Networks (EONs) allow to solve the high demand for bandwidth due to the increase in the number of internet users and the explosion of multicast applications. To support multicast applications, network operator computes a tree-shaped path, which is a set of optical channels. Generally, the demand for bandwidth on an optical channel is enormous so that, if there is a single fiber failure, it could cause a serious interruption in data transmission and a huge loss of data. To avoid serious interruption in data transmission, the tree-shaped path of a multicast connection may be protected. Several works have been proposed methods to do this. But these works may cause the duplication of some resources after recovery due to a link failure. Therefore, this duplication can lead to inefficient use of network resources. Our work consists to propose a method of protection that eliminates the link that causes duplication so that, the final backup path structure after link failure is a tree. Evaluations and analyses have shown that our method uses less backup resources than methods for protection of a multicast connection.