• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.1909-1928
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• 2011

Node cooperation during packet forwarding operations is critically important for fair resource utilization in Community Wireless Mesh Networks (CoWMNs). In a CoWMN, node cooperation is achieved by using fairness protocols specifically designed to detect and isolate malicious nodes, discourage unfair behavior, and encourage node participation in forwarding packets. In general, these protocols can be split into two groups: Incentive-based ones, which are managed centrally, and use credit allocation schemes. In contrast, reputation-based protocols that are decentralized, and rely on information exchange among neighboring nodes. Centrally managed protocols inevitably suffer from scalability problems. The decentralized, reputation-based protocols lacks in detection capability, suffer from false detections and error propagation compared to the centralized, incentive-based protocols. In this study, we present a new fairness protocol management scheme, called Hybrid FPMS that captures the superior detection capability of incentive-based fairness protocols without the scalability problems inherently expected from a centralized management scheme as a network's size and density grows. Simulation results show that Hybrid FPMS is more efficient than the current centralized approach and significantly reduces the network delays and overhead.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4623-4643
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• 2015

This paper considers physical-layer security protocols in multicast cognitive radio (CR) networks. In particular, we propose dual-hop cooperative decode-and-forward (DF) and randomize-and-forward (RF) schemes using partial relay selection method to enhance secrecy performance for secondary networks. In the DF protocol, the secondary relay would use same codebook with the secondary source to forward the source's signals to the secondary destination. Hence, the secondary eavesdropper can employ either maximal-ratio combining (MRC) or selection combining (SC) to combine signals received from the source and the selected relay. In RF protocol, different codebooks are used by the source and the relay to forward the source message secretly. For each scheme, we derive exact and asymptotic closed-form expressions of secrecy outage probability (SOP), non-zero secrecy capacity probability (NzSCP) in both independent and identically distributed (i.i.d.) and independent but non-identically distributed (i.n.i.d.) networks. Moreover, we also give a unified formula in an integral form for average secrecy capacity (ASC). Finally, our derivations are then validated by Monte-Carlo simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2091-2098
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• 2006

In this paper, it proposes a protocol of resource adaptive data dissemination for sensor nodes in a wireless sensor network. In general, each sensor node used in a wireless sensor network delivers the required information to the final destination by conducting cooperative works such as sensing, processing, and communicating each other using the battery power of a independent sensor node. So, a protocol used for transferring the acquired information to users through the wireless sensor network can minimize the power consumption of energy resource given to a sensor node. Especially, it is very important to minimize the total amount of power consumption with a method for handling the problems on implosion. data delivery overlapping, and excessive message transfer caused by message broadcasting. In this paper, for the maintaining of the shortest path between sensor nodes, maximizing of the life time of a sensor node and minimizing of communication cost, it presents a method for selecting the representative transfer node for an event arising area based on the negotiation scheme and maintaining optimal transfer path using hop and energy information. Finally, for the performance evaluation, we compare the proposed protocol to existing directed diffusion and SPIN protocol. And, with the simulation results, we show that the proposed protocol enhances the performance on the power consumption rate when the number of overall sensor nodes in a sensor network or neighbor sensor nodes in an event area are increased and on the number of messages disseminated from a sensor node.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.161-180
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• 2017

As the competition for securing cross-border biological sovereignty becomes intensified due to the adoption of the Nagoya Protocol, this study analyzed patent trends only for freshwater plants in order to secure national biological sovereignty. As a result, freshwater plants include a total of 68 genera and 128 species, and a total of 60 genera and 3,256 patents were surveyed. Among them, iris was the most industrialized, 14.71% followed by angelica(8.48%) and Mentha(6.94%). However, unconfirmed eight genera (Aneilema, Artemisia Cabomba, Nymphoides, Pistia stratiotes L., Pseudoraphis Griff., Ruppia) are not patented freshwater plants and it is expected that patent entry is high and barrier is low in the future. Based on patent results, Cooperative Patent Classification analysis was carried out and as a result, a total of 15 industry sectors were derived. And biopharmaceutical(30.24%) was found to be the most industrialized industry sector followed by agricultural chemistry (28.89%), biochemical industry (16.25%). In the biomedical industry, angelica(17.74%) was the most used and Iris (9.55%), Sium(20.56%) and angelica (20.48%) were found to be the most used in agricultural chemistry, biochemical industry and bio food industry, respectively. The analysis of detailed industry fields for 15 industry sectors showed that medicines of unknown structure containing substances from plants (37.77%), raw materials (46.57%) such as insect repellants, attracting agents and preparation of peptides(16.82%) with more than 21 amino acids were most frequently used in biopharmaceutical, agricultural chemistry and biochemical industry, respectively. This study is of significance as a basic data to know which freshwater plants are used in which field in order to secure biological sovereignty and patent analysis is considered necessary to continuously secure the biological sovereignty for freshwater plants.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.37-47
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• 2013

The objective of this research is to discover the rule of gameplay related to the task interdependence to analyse the behavior pattern of social gameplay. Previous literatures related to the gameplay were reviewed and game which was suitable for the gameplay of the task interdependence was selected. A party-play includes a team of five people in the experiment during the gameplay with think-aloud method and video/audio data about action protocol and verbal report were collected. The video observation and protocol analysis were conducted to analyse data. The objective coding scheme were developed from consolidated sequence model task analysis. The player's behavior was analysed. The result was revealed that four rules and four modified rules were included into the total eight behavior pattern. A behavior graph integrated with five gameplay was written. The excellent cooperative spot and error and failure place could be identified. The social gameplay behavior graph is expected to be the key practical design guideline on whether the level design and balance design are proper.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.57-67
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• 2015

A large amount of work has been done in the areas of routing, MAC, QoS, capacity, location service, cooperative communication, fault tolerance, mobility models and various applications of mesh networks thanks to their merits of cost-effective way of deployment and flexibility in extending wireline services. Although multi-path routing protocols have been proposed to be used to provide QoS and fault-tolerance, there has not been any significant results discussed that support both in the literature to our best knowledge as they are often required in military and public safety applications. In this paper, we present a novel routing protocol for a mesh network based on the OFDM-TDMA collision-free MAC that discovers and maintains multiple paths that allows retransmitting and forwarding packets that have been blocked due to a link failure using an alternative next-hop node such that the delay-capacity tradeoff is reduced and the reliability is enhanced. Simulation results show that the proposed protocol performs well in terms of both the QoS and delivery ratio.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.61-68
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• 2009

In this paper, we propose a Cluster-based Cooperative Routing using ARQ (CCRA) for supporting both reliability and transmitting efficient service in mobile ad-hoc wireless sensor networks with Rayleigh fading environments. The main contributions and features of this paper are as follows. First, the clustering method which uses the position information of nodes as underlying structure for supporting reliable transmission services is used. Second, the cooperative data transmission method based on the underlying clustering informations is used to improve both reliability and data transmission efficiency. Third, the ARQ-based transmission is used to improve transmission reliability. Fourth, we consider a realistic approach, in the points of view of mobile ad-hoc wireless sensor networks, based on mobile sensor nodes as well as fixed sensor nodes in the sensor fields while the conventional research for sensor networks focus on mainly fixed sensor networks. The performance evaluation of proposed routing protocol implemented via simulation using Optimized Network Engineering Tool (OPNET) and theoretical analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.426-435
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• 2013

The diversity-multiplexing tradeoff (DMT) functions of three special half-duplex (HD) dynamic decode-and-forward (DDF) protocols with multiple antennas only at the source node, only at the destination node, and only at the relay node are analytically derived. The DMT functions of these three relay protocols are compared with one another and with those of the nonorthogonal amplify and forward (NAF) protocols.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.711-716
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• 2003

This study considers the implementation issues of the inter-vehicle communication system for the vehicle platoon experiments via a testbed. The testbed, which consists of three scale vehicles and one RCS(remote control station), is developed as a tool for functions evaluation between simulation studies and full-sized vehicle researches in the previous study. The cooperative communication of the vehicle-to-vehicle or the vehicle-to-roadside plays a key role for keeping the relative spacing of vehicles small in a vehicle platoon. The static platoon control, where the number of vehicles remains constant, is sufficient for the information to be transmitted in the suitably fixed interval, while the dynamic platoon control such as merge or split requires more flexible network architecture for the dynamical coordination of the communication sequence. In this study, the wireless communication device and the reliable protocol of the flexible network architecture are implemented for our testbed, using the low-cost, ISM band transceiver and the 8-bit microcontroller.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.111-117
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• 2009

This paper presents an energy-efficient and bandwidth-efficient 2-1-1 relaying scheme in which a sensor node(SN) assists two others in their data transmission to a clusterhead in WSNs(Wireless Sensor Networks) using LEACH (Low-Energy Adaptive Clustering Hierarchy). We derive the closed-form BER expression of this scheme which is also a general BER one for the decode-and-forward cooperative protocol and prove that the proposed scheme performs the same as the conventional relaying scheme but obtains higher channel utilization efficiency. A variety of numerical results reveal the relaying can save the network energy up to 11 dB over single-hop transmission at BER of $10^{-3}$.