• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.5
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• pp.222-238
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• 2008

In this paper, the random key pre-distribution scheme introduced in ACM CCS'02 by Eschenauer and Gligor is reexamined, and a generalized form of key establishment is introduced. As the communication overhead is one of the most critical constraints of any successful protocol design, we introduce an alternative scheme in which the connectivity is maintained at the same level as in the original work, while the communication overhead is reduced by about 40% of the original overhead, for various carefully chosen parameters. The main modification relies on the use of a two-level key pool design and two round assignment/key establishment phases. Further analysis demonstrates the efficiency of our modification.

• Information Systems Review
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• v.5 no.2
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• pp.37-51
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• 2003

Mobile business noticed as a constructive alternative of e-commerce and e-business is being diversely considered as a new form or subset of e-business. In this study, mobile business is defined as a comprehensive alternative including e-business. The framework of the superset of e-business has two axes: connectivity and mobility. In addition, various cases based on the combination of the components are provided and explained. It is the main characteristic of this study that the element of off-line "mobility" is added to "connectivity" generally used while explaining e-commerce and e-business. For place (or location) is a prerequisite for the feature of mobility, we grope for why and how Location-Based Service (LBS) will take an important role in the development of new e-business models and services. As the real and full-scale beginning of IMT-2000 service and the rapid progress and diffusion of mobile communications services including wireless LAN require an immense and innovative way of thinking about e-commerce and e-business, the framework suggested in this study is considered to go far toward satisfying the new needs in this area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.589-592
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• 2005

The ubiquitous environment of the future has to exploit this multitude of connectivity alternatives resulting from diverse wireless communication systems and different access technologies to provide useful services with guaranteed quality to users. New applications require a ubiquitous environment capable of accessing information from different potable devices at any time and everywhere. This has motivated researchers to integrate various wireless platforms such as cellular networks., WLANs, and MANETs. Integration of different technologies with different capabilities and functionalities is an extremely complex task and involves issues at all layer of the protocol stack. This article compares and discusses a connection alternatives and integrated architecture in network layer for a SDR-based heterogeneous wireless network.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.525-535
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• 2011

In this paper, we study the contribution of network coding (NC) in improving the multicast capacity of random wireless ad hoc networks when nodes are endowed with multi-packet transmission (MPT) and multi-packet reception (MPR) capabilities. We show that a per session throughput capacity of ${\Theta}$(nT$^3$(n)) can be achieved as a tight bound when each session contains a constant number of sinks where n is the total number of nodes and T(n) is the transmission range. Surprisingly, an identical order capacity can be achieved when nodes have only MPR and MPT capabilities. This result proves that NC does not contribute to the order capacity of multicast traffic in wireless ad hoc networks when MPR and MPT are used in the network. The result is in sharp contrast to the general belief (conjecture) that NC improves the order capacity of multicast. Furthermore, if the communication range is selected to guarantee the connectivity in the network, i.e., ${\Omega}$($\sqrt{log\;n/n}$)=T(n) = O(log log n / log n), then the combination of MPR and MPT achieves a throughput capacity of ${\Theta}$(log$^{\frac{3}{2}}$ n/$\sqrt{n}$) which provides an order capacity gain of ${\Theta}$(log$^2$ n) compared to the point-to-point multicast capacity with the same number of destinations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2382-2388
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• 2014

To provide network reliability in indoor wireless communication systems, we should resolve the problem of unexpected network failure rapidly. In this paper, we propose an adaptive resource management (ARM) scheme to support seamless connectivity to users. In consideration of system throughput and user fairness simultaneously, the ARM scheme adaptively determines the set of healing channels, and performs scheduling and power allocation iteratively based on a constrained non-convex optimization technique. Through intensive simulations, we demonstrate the superior performance results of the proposed ARM scheme in terms of the average cell capacity and user fairness.

• The Journal of Information Technology
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• v.12 no.1
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• pp.15-20
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• 2009

In this paper, we aim that it solve to problem of the database hoarding because a week connectivity of wireless networks and cutting of link, Consistency of shared data, optimizing of the log include to Mobile Continuous Query Processing System under the mobile client and server environment. and we demonstrate of the superiority for the new Mobile Continuous Query Processing System compare C-I-S(Client-Intercept -Server)model with performance. and we perform to various experiment in order to establishment of superiority compare the index architecture and method for the realtime Continuous Query Processing. in this paper.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.342-345
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• 2008

본 논문에서는 대규모 무선 센서 네트워크에서 센서 노드와 게이트웨이를 배치하였을 때 연결성의 변화를 살펴본다. 2 차원의 감지목표지역에서 정해진 수로 균일 분포 과정으로 배치된 센서 노드들이 게이트웨이에 연결된 노드의 평균 비율을 통해 기대해 볼 수 연결 노드 비율을 확인하고, 이에 따라 적합한 게이트웨이의 수를 확인한다.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.357-364
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• 2014

The first mission for the IoT based hyper-connectivity communication is developing a device-to-device communication technique in infra-less low-power and lossy networks. In a low-power and lossy wireless network, IoT devices and routers cannot keep the original path toward the destination since they have the limited memory. Different from the previous light-weight routing protocols focusing on the reduction of the control messages, the proposed scheme provides the light-weight IPv6 address auto-configuration, IPv6 neighbor discovery and routing protocol in a IoT capable infra-less wireless networks with the bloom filer and enhanced rank concepts. And for the first time we evaluate our proposed scheme based on the modeling of various probability distributions in the IoT environments with the lossy wireless link. Specifically, the proposed enhanced RPL based light-weight routing protocol improves the robustness with the multi-paths locally established based on the enhanced rank concepts even though lossy wireless links are existed. We showed the improvements of the proposed scheme up to 40% than the RPL based protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9B
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• pp.760-766
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• 2008

As a backbone network, wireless mesh network (WMN) aims to provide reliable high throughput network connectivity to wireless users. Recent research has focused on routing and channel allocation to increase the capacity of wireless mesh backbones. Wireless mesh networking is an attractive solution for home, community, and enterprise networks as it is a self-configuring, instantly deployable, and lowcost networking system. In this paper, we empirically evaluate and analyze charateristic of WMN to establish WMN testbed by measurement. We use laptops and net4826 Soekris board widely used. Soekris boards are equipped with one network interface card (NIC) or above in our measurements. We also use paket generator, routing demon tools and so on. Throughout this measurements, we show limitation of Soekris board and software we use, and suggest guideline to establish WMN.

• ETRI Journal
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• v.36 no.3
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• pp.374-384
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• 2014

To achieve high-speed (giga-bit) connectivity for short-range wireless multimedia applications, the millimeter-wave (mmWave) wireless personal area networks with directional antennas are gaining increased interest. Due to the use of directional antennas and mmWave communications, the probability of non-interfering transmissions increases in a localized region. Network throughput can be increased immensely by the concurrent time allocation of non-interfering transmissions. The problem of finding optimum time allocation for concurrent transmissions is an NP-hard problem. In this paper, we propose two enhanced versions of previously proposed multi-hop concurrent transmission (MHCT) schemes. To increase network capacity, the proposed schemes efficiently make use of the free holes in the time-allocation map of the MHCT scheme; thus, making it more compact.