• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.36-43
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• 2009

In this paper, we propose a Cooperative Routing using ARQ-based Transmission (CRARQ) in Mobile Ad-hoc Wireless Sensor Networks (MAWSN). The goals of the CRARQ are to improve both the efficiency of transmission and the reliability of transmission together. The main features and contributions of the proposed CRARQ for supporting these goals are as follows. First, CRARQ uses a reactive concept to construct a route from a source to a destination. Second, CRARQ chooses the most stable relay at each hop along the route by mobility-based strategy. Third, cooperative transmission using the ARQ technique which can improve reliability is used at each hop to send data packets from source to destination. Finally, we present a theoretical analysis model for the proposed CRARQ. The performance evaluation of our protocol is implemented via simulation using Optimized Network Engineering Tool (OPNET) and analysis. The results of both simulation and analysis show that CRARQ achieves the improved packet delivery ratio (PDR) and outage probability.

• Convergence Security Journal
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• v.11 no.6
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• pp.37-44
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• 2011

VANET(Vehicular Ad-hoc Network) is a kind of ad hoc networks consist of intelligence vehicular ad nodes, and has become a hot emerging research project in many field. It provide traffic safety, cooperative driving and etc. but has also some security problems that can be occurred in general ad hoc networks. Also, in VANET, vehicles shoul d be able to authenticate each other to securely communicate with network-based infrastructure, and their locations and identifiers should not be exposed from the communication messages. This paper proposes V2I(Vehicular to Infra structure) authentication protocol that anonymity and untraceability of vehicular using Error Correcting Code that ge nerate encoding certification using generation matrix. The proposed scheme based on ECC resolves overhead problems of vehicular secure key management of KDC.

• Journal of Digital Contents Society
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• v.17 no.1
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• pp.65-70
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• 2016

This paper suggests an environment of a CSCW(Computer Supported Cooperative Works) for industry safety service. A good example of industry safety service is gunpowder. This paper proposed a computer-based integrated multimedia for industry safety service running on shepherd and SIP(Session Initiation Protocol). But, conventional framework has not yet fully progressed a shepherd for computer-based integrated multimedia running on SIP(Session Initiation Protocol). Session management include function of session creation, session end, late comer process, and access control. Therefore, this paper described an environment of integrated multimedia based on a shepherd and SIP environment to maintain good session condition.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.303-310
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• 2008

Recently, IEC 61850 supports the standardized communication technique in both station bus and process bus, and presents substation automation model. In order to implement the IEC 61850 based communication in a substation using the MU (merging unit) which is one of the important data acquisition equipments in substation automation, the time synchronization is demanded for cooperative operation between the devices. This paper proposes the precision time synchronization technique using IRIG-B protocol to develop the MU under IEC 61850 communication protocol. The proposed technique is implemented and its performance is verified experimentally.

• Journal of the Korean Society for information Management
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• v.22 no.1 s.55
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• pp.229-248
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• 2005

This study proposes a national cooperative model of access point control, that enables local systems to utilize national access point control record, without creating their own authority records. In order to applying this model, a client/server system is developed using SRU (Search and Retrieve URL Service) protocol. The suggested access point control system will be a cost-effective and time-saving model for the local system, and will be more flexible and extensible with concept of access point control, XML record format and SRU protocol.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.45-50
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• 2014

In this paper, we proposed a method using the user mobile device to overcome the interference constraint without building a cooperative communication system. In addition, in order to mitigate interference, we apply the user mobile device selection method, and then exploit power allocation scheme in the user mobile device. The proposed protocol is analyzed in the Rayleigh fading environment, and the performance system is evaluated in terms of the bit error rate and the outage probability. The simulation results showed that when the proposed transmission algorithm is applied, the interference can be mitigated. Further, network overload problems can be solved in the weak channel interference. Therefore, we can increase the network capacity without additional relay.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2354-2370
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• 2015

The advantages of employing SCTP-based Concurrent Multipath Transfer (CMT) have been demonstrated to be very useful for data delivery over multi-homed wireless networks. However, there is still significant ongoing work addressing some remaining limitations and challenges. The most important concern when applying CMT to data delivery is related to handling packet reordering and buffer blocking. Another concern on this topic is that current sender-based CMT solutions seldom consider balancing the overhead and sharing the load between the sender and receiver. This paper proposes a novel Receiver-driven Cooperation-based Concurrent Multipath Transfer solution (CMT-Rev) with the following aims: (i) to balance overhead and share load between the sender and receiver, by moving some functions including congestion and flow control from the sender onto receiver; (ii) to mitigate the data reordering and buffer blocking problems, by using an adaptive receiver-cooperative path aggregation model, (iii) to adaptively transmit packets over multiple paths according to their receiver-inspired sending rate values, by employing a new receiver-aware data distribution scheduler. Simulation results show that CMT-Rev outperforms the existing CMT solutions in terms of data delivery performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1357-1372
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• 2017

Energy harvesting techniques, particularly radio frequency energy harvesting (RF-EH) techniques, which are known to provide feasible solutions to enhance the performance of energy constrained wireless communication systems, have gained increasing attention. In this paper, we consider a wireless-powered cooperative communication network (WPCCN) for transferring energy in the downlink and forwarding signals in the uplink. The objective is to maximize the average transmission rate of the system, subject to the total network power constraint. We formulate such a problem as a form of wireless energy transmission based on resource allocation that searches for the joint subcarrier pairing and the time and power allocation, and this can be solved by using a dual approach. Simulation results show that the proposed joint optimal scheme can efficiently improve system performance with an increase in the number of subcarriers and relays.

• The Journal of Korean Medicine
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• v.24 no.4
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• pp.64-70
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• 2003

Background and Purpose : Allergic rhinitis is a well-known, relatively controllable chronic disease. Although a number of methods for treating allergic rhinitis have been tried, many patients have not been satisfied with their treatment. Therefore, this study tried to evaluate the effect of a cooperative system of Oriental and Western medicine and to develop a new diagnosis protocol for treatment of allergic rhinitis. Methods : We measured improvement rate and acoustic rhinometry after the allergeninduction test and performed a filter paper test as a nonspecific hypersensitivity test with 60 patients who are allergic to house dust mite. Patients were divided into two groups, one treated with Western medicine only and one treated with both Western and Oriental herbal medicine. For the group with Western medicine only, antihistamine for one week and local steroid medicine for two weeks were prescribed. For the group with combined medicine, Oriental herbal medicine was prescribed according to the patient s constitution, along with Western medicine. After all treatments, the above tests were re-performed and the improvement rate was compared. Results and Conclusion : We observed better results in the group treated with both Western and Oriental herbal medicines, comparing improvement rate and the alteration of total nasal volume through acoustic rhinometry after the allergen induction test. In the filter paper test, there was no significant difference between the two groups. In conclusion, we showed the additive effect of Oriental herbal medicine without any severe side effects compared with treatment with Western medicine only. In this study, we set only two patient groups, but further study is required to create various experimental groups and compare among them. We suggest that it might enhance understanding of the improved effect of Oriental herbal medicine in the therapy of allergic rhinitis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1C
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• pp.1-7
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• 2010

In this paper, the performance of the soft-decision-and-forward (SDF) protocol in the cooperative communication network with one source, one relay, and one destination, where each node has two transmit and receive antennas, is analyzed in terms of the bit error rate (BER) obtained from the pairwise error probability (PEP). For the slow-varying Rayleigh fading channel, the optimal and suboptimal power allocation ratios are determined without feedback. The optimal power allocation can be obtained by minimizing the average PEP. For the tractability, an alternative strategy of maximizing the product SNR of direct and relay links, which we call the suboptimal power allocation, is considered. Through the numerical analysis, we show that the performance gap between the suboptimal and the optimal power allocation is negligible in the high SNR region.