• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.365-371
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• 2012

In recent years, researchers have been attracted to clustering methods to improve communication and data transmission in a network. Compared with traditional wireless networks, wireless sensor networks are energy constrained and have lower data rates. The concept of implementing a clustering algorithm in an existing project on gateway relocation is being explored here. Low energy adaptive clustering hierarchy (LEACH) is applied to an existing study on relocating a gateway. The study is further improved by moving the gateway to a specific cluster based on the number or significance of the events detected. The protocol is improved so that each cluster head can communicate with a mobile gateway. The cluster heads are the only nodes that can communicate with the mobile gateway when it (the mobile gateway) is out of the cluster nodes' transmission range. Once the gateway is in range, the nodes will begin their transmission of real-time data. This alleviates the load of the nodes that would be located closest to the gateway if it were static.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1599-1610
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• 2019

Intelligent services have expanded as Internet of Things (IoT) technology has evolved and new requirements emerge to accommodate various services. One new requirement is transmitting data over long distances with low-power. Researchers have developed low power wide area (LPWA) network technology to satisfy the requirement; this can improve IoT network infrastructure and increase the range of services. However, network coverage expansion causes several problems. The traffic load is concentrated at a specific gateway, which causes network congestion and leads to decreased transmission efficiency. Therefore, the approach proposed in this paper attempts to recognize and then avoid congestion through gateway channel hopping. The LPWA network employs multiple channels, so wireless channel hopping is available in a gateway. Devices that are not delay sensitive wait for the gateway to reappear on their wireless channel; delay sensitive devices change the wireless channel along the hopping gateway. Thus, the traffic load and congestion in each wireless channel can be reduced improving transmission efficiency. The proposed approach's performance is evaluated by computer simulation and verified in terms of transmission efficiency.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.3
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• pp.176-180
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• 2009

This paper investigates protocol architecture for a web-sensor gateway interconnecting internet and wireless sensor network, in which Zigbee sensors are connected over the IEEE802.15.4 communication protocol standard. The web-sensor gateway is to deliver data between TCP/IP and Zigbee/IEEE802.15.4 protocols, transparently. Since the gateway provides a means to remotely control and aggregate sensor data over the internet, it needs to be designed in the view point of users and in their convenience. In accordance, the common gateway interface technology satisfying users on the web browser to efficiently manage and query the sensors in the wireless sensor networks, ubiquitously, is also introduced. Finally, a simulation prototype for the web-sensor gateway is proposed and verified using OPNET simulation tool.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.175-177
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• 2007

This paper is concerned with a performance analysis using a wired/wireless gateway based on DeviceNet. For the performance analysis, the data transmission time between DeviceNet and the wireless devices is investigated and analyzed. The experimental results show the perfom1ance in terms of the polling/COS service time and end-to-end delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.576-583
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• 2010

Wireless Internet is the network which provides wireless access in order to serve the Internet connections and data communication through the mobile handsets. To get efficient wireless access to the Internet, we need the WAP (Wireless Application Protocol) gateway that performs protocol translation and contents conversion between two different networks. We need the capacity dimensioning of the WAP gateway system in order to provide the wireless Internet service stably and cost-effectively. We also need the traffic engineering methods including traffic modelling and forecasting for the economical facility investment. The existing method of WAP gateway capacity dimensioning was intuitive and qualitative. But in this paper, we deal with the capacity dimensioning analytically and quantitatively on the basis of WAP traffic description parameters and traffic forecasting method.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.101-107
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• 2009

In existing wireless ad-hoc networks, how to distribute network resources fairly between many users to optimize data transmission is an important research subject. However, in wireless mesh networks (WMNs), it is one of the research areas to avoid gateway bottleneck more than the fair network resource sharing. It is because WMN traffic are concentrated on the gateway connected to backhaul. To solve this problem, the paper proposes Weighted Fairness Time-sharing Access (WFTA). The proposed WFTA is a priority time scheduling scheme based on Weighted Fair Queuing (WFQ).

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.151-154
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• 2010

In this paper, we propose an energy monitoring and management service based on wireless sensors and a home gateway for homes and buildings. Homes and buildings have a significant energy saving potential compared with other sectors. Sensing, monitoring, and managing of the information on the energy consumption are required for an efficient energy saving service. The proposed system is composed of two main components, wireless sensor and an intelligent home gateway. Wireless sensors have the ZigBee communication interface for communication, and the intelligent home gateway is an energy portal. We expect that energy saving could be achieved with this system. As a further work, we will analyze the practical impact of the proposed service.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.333-338
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• 2014

Zigbee is a wireless communication technology optimized for WSN (Wireless Sensor Network) environment. A WSN gateway is used for node control and data transmission. However, a fixed-type gateway can restrict the flexibility of the WSN environment. A smartphone-mounted high-performance processor and Android OS can be easily used in a mobile WSN gateway. In this paper, we proposed a mobile WSN gateway based on Android smartphones. In the proposed system, a Zigbee sensor module is connected with a smartphone via USB (Universal Serial Bus) port. We also implemented an Android application for the mobile WSN gateway.

• Journal of Internet Computing and Services
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• v.6 no.3
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• pp.45-54
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• 2005

Recently, researches on various base technologies for wireless Internet services have been conducted. In the WAP (Wireless Application Protocol) Forum, a WAP gateway which does mutual conversion between existent wired Internet protocols and WAP protocols was proposed. In this paper, CSA(Client Side Agent) and SSA(Server Side Agent) for WAP gateway environments are designed and implemented, as a way of improving communication efficiency in such restrictive environments as wireless communications. Located on mobile WAP devices(CSA) and a WAP Gateway(SSA), the agents perform communication efficiency improvement activities such as a packet header reduction mechanism and a data reduction mechanism using data differencing analysis in order to reduce the size of data transmission in wireless communication environments. The Internet phone emulator of Phone.com is used in order to make sure that the implemented agents work correctly, Experimental results show that the implemented agents reduce the size of data transmission significantly.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.24-51
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• 2011

When supporting both voice and TCP in a wireless multihop network, there are two conflicting goals: to protect the VoIP traffic, and to completely utilize the remaining capacity for TCP. We investigate the interaction between these two popular categories of traffic and find that conventional solution approaches, such as enhanced TCP variants, priority queues, bandwidth limitation, and traffic shaping do not always achieve the goals. TCP and VoIP traffic do not easily coexist because of TCP aggressiveness and data burstiness, and the (self-) interference nature of multihop traffic. We found that enhanced TCP variants fail to coexist with VoIP in the wireless multihop scenarios. Surprisingly, even priority schemes, including those built into the MAC such as RTS/CTS or 802.11e generally cannot protect voice, as they do not account for the interference outside communication range. We present VAGP (Voice Adaptive Gateway Pacer) - an adaptive bandwidth control algorithm at the access gateway that dynamically paces wired-to-wireless TCP data flows based on VoIP traffic status. VAGP continuously monitors the quality of VoIP flows at the gateway and controls the bandwidth used by TCP flows before entering the wireless multihop. To also maintain utilization and TCP performance, VAGP employs TCP specific mechanisms that suppress certain retransmissions across the wireless multihop. Compared to previous proposals for improving TCP over wireless multihop, we show that VAGP retains the end-to-end semantics of TCP, does not require modifications of endpoints, and works in a variety of conditions: different TCP variants, multiple flows, and internet delays, different patterns of interference, different multihop topologies, and different traffic patterns.