Taehun Yang

Sink Mobility Support Scheme for Continuous Object Tracking in Wireless Sensor Networks

In wireless sensor networks, one of the most important application is tracking diffusive and large-scale phenomena, called continuous object. A number of sources from the large size of a continuous object bring huge communication overhead that former studies have to deal with. Meanwhile, recent application scenarios, such as forest fire suppression by firefighters, require sink mobility support. Most sink mobility support schemes have proposed for individual object tracking. They provide one-to-one connection between a mobile sink and a source. That is, too many connections resulting excess energy consumption are built if continuous object tracking directly adopts them. In this paper, we propose a solution to the problem with building a one-to-many connection between a sink and sources detecting a continuous object. The proposed scheme gradually extends the initial connection between a sink and the first source according to the spread of the continuous object. Our simulation results show that the proposed scheme is superior to existing schemes in terms of energy consumption.

Reliable push notification for mobile users in interactive smart mobile applications: poster abstract

Nowadays, mobile applications are engaged with and depended on the physical world more and more. Interaction with a certain proximity and thing is bringing smarter services into our daily lives through cyber-physical world collaboration. Push notification of meaningful content associated with the proximity or thing is one of key technologies of the cyber-physical services. For example, empty parking spot recommendation in a parking lot or promotion coupon notification of a shop at a shopping cent er should be delivered accordingly. This paper explores reliable push notification of content for novel interactive mobile applications over Bluetooth Low Energy (BLE) beacon infrastructure. Since mobile users move around with different speeds, this paper deals with such difference to relay right content in a reliable manner, called Reliable Push Notification (RPN). RPN dynamically clusters contents and links them to a beacon to achieve reliability, and then adaptively pre-allocate contents for transmission.

Low-Cost Multipath Routing Protocol by Adapting Opportunistic Routing in Wireless Sensor Networks

The wireless sensor networks (WSNs) are special network which has purpose of gathering information in certain area. The reliability is an important factor in the WSNs for transferring the information to the destination. However, the reliability is decreased while multi-hop transmission of the information because a node which composes the WSNs has limited communication range. Also, the transmission process may suffer from the various factors including the faulty nodes and network congestion. To solve this, the multipath routing protocols, which transfer the information through a multipath to the destination at the same time, have been proposed for improving the reliability. In the existing multipath routing protocols, however, the network scale should be sufficient for constructing multipath to guarantee of the disjoint path and the energy is consumed for multipath construction#x002F;maintenance consistently. The energy consumption leads to the reduction of networks lifetime and the restricted network scale may not even ensure the enough reliability. Thus, we proposed Low-Cost Multipath Routing Protocol by Adapting Opportunistic Routing which can reduce consistent energy consumption and less affected by network scale. The proposed protocol exploits the opportunistic routing that improves the single-hop reliability in order to improve the reliability in each path. It reduces the number of paths, which constructed for ensuring the enough reliability. Also, a fewer path reduces the energy consumption and alleviates the restriction of network scale. Simulation results show that the proposed protocol provides the more reliable performance than the existing protocols in the network, which restricted scale, and consumes the less energy.

Multipath Management Scheme for Supporting Sink Mobility in Wireless Sensor Networks

In wireless sensor networks, sink mobility support is one of the essential functionality in many applications. With continuous advancement, the future applications will require not only sink mobility but also high performance. Multipath routing is one of the promising technologies for improving network performance. However, existing multipath routing protocols have not dealt with the sink mobility. As a result, they lead to bad performance in terms of energy efficiency due to the end-to-end path reconstruction. Consequently, a novel path management scheme is required thereby supporting sink mobility without performance degradation. In this paper we propose a multipath management scheme for supporting sink mobility. The proposed scheme dynamically constructs multipath along the moving path of a sink. In addition, the proposed scheme provides the path shortening mechanism according to the sinks movement for reducing energy consumption. Our simulation results show that the proposed scheme is superior to existing path management schemes in terms of reliability and energy efficiency.

Poster Abstract: Enhanced Real-Time Transmission Using Time Gain in Wireless Sensor Networks

Real-time applications in wireless sensor networks require that packets should reach to a sink within the time deadline. To satisfy the requirements, existing studies exploit nodes whose speed is higher than the desired delivery speed decided by the spatiotemporal approach. However, they fail real-time transmission in the area where there is no neighbor nodes which meet the requirements toward a sink since the desired delivery speed is fixed. This paper proposes a scheme to pass the area using time gain which occurs by the nature of the existing real-time transmission scheme. Thus, in the area, a sending node could make full use of nodes which do not satisfy the requirements. In the end, the packet passes across the area with a lower speed than the desired delivery speed. The simulation results show that the proposed scheme is superior in terms of real-time transmission success ratio to the existing schemes.

Multipath-based opportunistic routing scheme for large-scale wireless sensor network

Opportunistic routing (OR) has been emerged as a promising routing strategy to improve transmission reliability for wireless networks. By taking broadcast nature of wireless medium, a set of forwarding candidate nodes receive a data packet simultaneously, so one of them can relay it unless they all fail to receive. This strategy can dramatically improve one-hop reliability even in unreliable wireless links, however, it cannot be directly applied into large-scale wireless multi-hop networks since multi-hop communication significantly decreases end-to-end reliability. In this letter, we propose a novel opportunistic routing scheme for large-scale wireless multi-hop networks, which adopts multipath based routing in order to improve end-to-end reliability. While taking advantages of opportunistic routing, each intermediate node can determine whether it branches into multiple paths or not without any network topology information, so that a desired delivery ratio from a source to a destination given by application demands can be achieved in a fully localized manner.