• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.69-77
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• 2012

This study observes the purchased lands in riparian areas of Suncheon City region and proposes a reasonable management method. For the study, the site surveying and analysis on the neglected purchased lands is executed, then, based on the site analysis result, the appropriate management method for each neglected purchased land is established. Each management method is approached from the ecological restoration perspective. According to site surveying and analysis of the neglected purchased lands, most of the sites were bare and agricultural lands. The reason for this is thought to be as when purchasing a land, the areas with higher nonpoint source pollution are bought preferentially. As for the dominant species coverage, 26% ($364,000m^2$) of the total neglected purchased land area in Sucheon City was covered with the dominated species, and for the exotic species coverage, 17% ($232,000m^2$) of the total neglected purchased land area in Sucheon City was covered with the exotic species. The survey site constituted of five different invasive species such as Japanese Hop (Humulus japonicus), Daisy Fleabane (Erigeron annuus), and Evening Primrose (Oenothera odorata). As for the natural succession on site, about 47% of the area showed poor natural succession process. The reason for this outcome is understood as having a lack of appropriate management for purchased lands. Based on the site surveying and analysis, especially the current management state of the and its location, the research site was categorized into preservation, restoration, and improvement sites. During the establishment of the ecological riparian belt, the comprehensive management for preservation, restoration, and improvement of the purchased lands should be executed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.29-34
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• 2008

In this paper, we proposed a system protocol for detecting injurious insect to support energy saving transmission in wireless bio sensor networks. The main ideas and features of the system are as follows. First, the route establishment method which is based on the energy efficiency and stability by using time-division tree structure. Second, multi-hop direction-based data gatering structure. In this structure, the selected fading method is used to transmit packet via the established tree structure for supporting power saving and route lifetime efficiently. Finally, we can get the node power saving and reduce transmission delay, thus network lifetime and efficiency are improved. The performance evaluation of the proposed protocol is via OPNET(Optimized Network Engineering Tool).

• Journal of Korea Multimedia Society
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• v.9 no.2
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• pp.244-254
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• 2006

This paper presents an efficient hybrid technique to compact the trie indexing the huge forward table small enough to be stored into cache for speeding up IP lookup. It combines two techniques, an encoding scheme called bit-map and a controlled-prefix expanding scheme to replace slow memory search with few fast-memory accesses and computations. For compaction, the bit-map represents each index and child pointer with one bit respectively. For example, when one node denotes n bits, the bit-map gives a high compression rate by consumes $2^{n-1}$ bits for $2^n$ index and child link pointers branched out of the node. The controlled-prefix expanding scheme determines the number of address bits represented by all root node of each trie's level. At this time, controlled-prefix scheme use a dynamic programming technique to get a smallest trie memory size with given number of trie's level. This paper proposes standard that can choose suitable trie structure depending on memory size of system and the required IP lookup speed presenting optimal memory size and the lookup speed according to trie level number.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.65-73
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• 2004

In this paper, we propose a tunnel establishment scheme using Next Hop Resolution Protocol over mobile IP networks, which consist of LAN-based IP networks and ATM-based IP networks. As a basic idea, we use the shortest path algorithm to establish a short-cut tunnel between HA and FA. Also, we classify methods for establishing a short-cut tunnel into four cases considering the locations of HA, FA, CN and MN. To confirm the advantages of our schemes, which deliver packets using short-cut tunnel in optimized path method over mobile IP networks, we performed mathematical analysis and simulation, compared proposed schemes with existing IP routing method in terms of transmission delay between CN and MN. The simulation results show that our scheme have superior performance to that of existing IP routing mechanism, because the store-and-forward delay which occurred in IP routing mechanism is considerably reduced in short-cut tunnel over ATM networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.829-836
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• 2013

Wireless mesh networks(WMNs) are wireless backbone networks technology consisting of a multi-hop routers. Location management is essential to provide a service to the terminal in WMNs. IEEE 802.11s standards have two basic location management scheme for location management - the proxy registration procedure and the associated station discovery protocol. These basic schemes, however, suffer from serious drawbacks including redundancy control message, ineffective location information maintenance, additional delay time. This paper propose an on-demand station location management scheme using 6-address structure of IEEE 802.11s. Through analysis and experimental evaluation on simulation, we show that proposal scheme reduce control message and forwarding delay time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.31-34
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• 2012

In MANET, frequent movement of nodes causes the dynamic network topology changes. Therefore the routing protocol, which is very stable to effectively respond the changes of the network changes, is required. Moreover, the existing cluster-based routing protocol, that is the hybrid approach, has routing delay due to the re-electing of the cluster header. In addition, the routing table of CBRP has all only one hop distant neighbor nodes. PCBRP, proposed in this paper, ties two clusters in one pair of clusters to make longer radius. Then the pair of the cluster headers manages and operates corresponding member nodes. When they route nodes in the paired cluster internally, PCBRP reduces the delay by requesting a route. Therefore PCBRP shows improved total delay of the network and improved performance of packet transmitting rate.

• Journal of Internet of Things and Convergence
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• v.6 no.3
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• pp.1-6
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• 2020

This paper aims to integrate the previous models about mean object transfer latency in one framework and analyze the result through the computational experience. The analytical object transfer latency model assumes the multiple packet losses and the Internet of Things(IoT) environment including multi-hop wireless network, where fast re-transmission is not possible due to small window. The model also considers the initial congestion window size and the multiple packet loss in one congestion window. Performance evaluation shows that the lower and upper bounds of the mean object transfer latency are almost the same when both transfer object size and packet loss rate are small. However, as packet loss rate increases, the size of the initial congestion window and the round-trip time affect the upper and lower bounds of the mean object transfer latency.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.905-916
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• 2004

Self-organizing hierarchical ad hoc network (SOHAN) is a new ad-hoc network architecture designed to improve the scalability properties of conventional 'flat' ad hoc networks. This network architecture consists of three tiers of ad-hoc nodes, i.e.. access points, forwarding nodes and mobile nodes. This paper presents a topology discovery and routing protocol for the self-organization of SOHAN. We propose a cross-layer path metric based on link quality and MAC delay which plays a key role in producing an optimal cluster-based hierarchical topology with high throughput capacity. The topology discovery protocol provides the basis for routing which takes place in layer 2.5 using MAC addresses. The routing protocol is based on AODV with appropriate modifications to take advantage of the hierarchical topology and interact with the discovery protocol. Simulation results are presented which show the improved performance as well as scalability properties of SOHAN in terms of through-put capacity, end-to-end delay, packet delivery ratio and control overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.619-629
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• 2005

In this paper, we propose energy-aware routing schemes which are simple enough to be applicable to the wireless sensor networks. The one hop upstream no de in direction of the base-station is determined in four different ways based on the energy information of neighboring nodes, which are obtainable via the process of self-organization of the network. The fair distribution of the energy consumption over all the possible routes to the base-station is one of the design objectives. Also, an alternate route search mechanism is proposed to cope with the situation in which no routing information is available due to lack of remaining energy of the neighboring nodes. The mechanism turns out to be a supplementary scheme to improve the energy efficiency. Lots of simulations are performed to examine the performance metrics such as the energy efficiency, throughput, network lifetime, and the transmission latency of the proposed schemes. Simulation results show the feasibility of the simple routing schemes for the sensor networks.

• Journal of Communications and Networks
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• v.6 no.3
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• pp.269-279
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• 2004

A new online multi-layer integrated routing (MLIR) scheme that combines IP (electrical) layer routing with WDM (optical) layer routing is investigated. It is a highly efficient and cost-effective routing scheme viable for the next generation integrated optical Internet. A new simplified weighted graph model for the integrated optical Internet consisted of optical routers with multi-granularity optical-electrical hybrid switching capability is firstly proposed. Then, based on the proposed graph model, we develop an online integrated routing scheme called differentiated weighted fair algorithm (DWFA) employing adaptive admission control (routing) strategies with the motivation of service/bandwidth differentiation, which can jointly solve multi-layer routing problem by simply applying the minimal weighted path computation algorithm. The major objective of DWFA is fourfold: 1) Quality of service (QoS) routing for traffic requests with various priorities; 2) blocking fairness for traffic requests with various bandwidth granularities; 3) adaptive routing according to the policy parameters from service provider; 4) lower computational complexity. Simulation results show that DWFA performs better than traditional overlay routing schemes such as optical-first-routing (OFR) and electrical-first-routing (EFR), in terms of traffic blocking ratio, traffic blocking fairness, average traffic logical hop counts, and global network resource utilization. It has been proved that the DWFA is a simple, comprehensive, and practical scheme of integrated routing in optical Internet for service providers.