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Wireless sensor networks based on the IEEE 802.15.4 standard is able to achieve low-power transmissions in low-rate and short-distance wireless personal area networks (WPANs). It employs the slotted carrier sense multiple access with collision avoidance (CSMA/CA) in the contention access period (CAP). Unfortunately the periodic broadcast beacon frame is transmitted without CSMA/CA so that it could...
File replication and consistency are well known techniques in distributed systems to address the key issues such as scalability, reliability and fault tolerance. For many years, file replication and consistency in distributed environment has been researched to enhance and optimize the availability and reliability of the entire system. An effort has been made in the present work to propose a file popularity...
Ultra-wideband (UWB) transmission is an emerging wireless communication technology that is gaining significant interest for future broadband wireless access. This transmission technique based mainly on the Impulse-Radio (IR) paradigm, has the potential to deliver high-speed wireless connectivity at low power and low proximity, characteristics that makes it an ideal choice for wireless sensor networks...
Requirements on end-to-end latency and jitter are becoming more and more important due to new real-time services ‘delay sensitive’ to be transported. Capability to support measurements of end-to-end latency and jitter is essential in particular for Carrier Ethernet products [1]. This paper addresses a concrete example of measurement of the end-to-end latency and jitter in a Carrier Ethernet network...
In peer-to-peer (P2P) overlay networks, a group of multiple peers have to cooperate with each other. P2P systems are in nature scalable, distributed systems, where there is no centralized coordinator. Hence, a group of peers is required to be scalable in P2P overlay networks. Each peer sends a message to every peer and every other peer receives the message in a group. In group communication, each...
Process algebra for quantitative evaluation are based on either of the two following mechanisms for communication: binary, where a channel is shared by exactly two agents, or multiway, where all agents sharing a channel must synchronise. In this paper we consider an intermediate form which we call generalised communication, where only m agents out of n potentially available are involved in the communication...
Due to the oceanic climate and frequent earthquakes in Japan, bridge health diagnosis is a problem of greater complexity. In bridge diagnosis system, we develop a wireless sensor network to sample and gather the vibration data of bridge. Time synchronization is a crucial component for the wireless sensor network (WSN), because large populations of sensor nodes will collaborate in order to complete...
This paper describes the ROMEO architecture for live 3D multi-view video delivery over peer-to-peer networks. The scope of the European founded Integration Project ROMEO encompasses addressing the challenges of live multiview video delivery over heterogeneous networks (WiFi, LTE, DVB, etc.) and diverse user equipment (mobile, portable, fixed). In order to achieve seamless uninterrupted 3D video delivery...
To securely exchange data over public networks, such as the Internet, organizations often utilize Virtual Private Networks (VPNs). However, relying on these potentially large overlay networks makes them vital targets for Denial-of-Service(DoS) attacks. Thus, recent approaches for VPN auto-configuration address DoS resistance by employing distributed management algorithms. Nevertheless, there is no...
This paper presents a conceptual framework of new type of hybrid peer-to-peer distributed groupware and its prototype implementation in a simple scenario of learning case study as a prove of concept. The CSCL (Computer Supported Collaborative Learning) tool developed, demonstrates a typical virtual classroom scenario with scheduled workflow among participants. The key architecture of the prototype...
A key aspect of a wireless sensor network is its ability to self-organize and maintain connectivity. Medium Access Control (MAC) protocol manages network self-configuration, which includes establishing a personal area network (PAN), finding a network to associate or disassociate with, and synchronizing if required. Currently, there is limited research that addresses the network initialization phase...
Single channel wireless sensor networks may be unreliable when the channel of choice is either unstable or interfered. Previous work has shown that multi-channel solutions could effectively improve network reliability and deliver higher throughput as well. While a number of multi-channel medium access control schemes have been proposed, there are not much work on routing protocol design addressing...
Small playback lag in live streaming is important for time-critical and interactive applications such as live stock, market updates, sports and remote education. In this paper, we present Elite addresses the playback lag problem in peer-assisted live streaming systems. Instead of deploying a large initial offset to all the users, Elite seeks the possibility of initializing users with layered proportional...
This paper describes the current Smart high voltage substation where Merging Units and other protection devices require high-precision time synchronization, and analyzes the time synchronization significant role in the Smart substation. With the expansion of the IEC 61850 standard in Smart substation automation applying, the IEEE 1588 which can achieve sub-microsecond level of accuracy seems to be...
Distributed beamforming technique has been introduced in the wireless sensor network (WANs) in order to increase the transmission range and signal strength of sensor node. The identical data is transmitted to the destination by all nodes which have timing and carrier synchronously. Then, the data transmissions are combined gainfully at the destination. Thus accuracy of reference signal for synchronization...
This paper presents the mapping of the High-Availability Seamless Redundancy (HSR) protocol to PROFINET RT. Whereas common PROFINET RT components that implement the Media Redundancy Protocol (MRP) are requiring up to 200 ms for recovery after link failures, HSR provides seamless redundancy. In order to overcome the incompatibilities between PROFINET and HSR a configurable HSR RedBox is implemented...
This paper surveys previous distributed storage systems and related data redundancy and fault-tolerance schemes which are introduced to overcome the impact of host churn on data reliability. Furthermore, a hybrid storage system model is proposed which offers a reliable data storage service by integrating idle storage contributed by volatile peer nodes and stable and durable storage utilities. In order...
Conventional distributed system courses follow a syllabus in which a list of topics is discussed independently and at different levels of abstractions. We propose to use a wireless sensor network environment to pin all topics down to concrete applications and to maintain issues such as fault tolerance and coordination continuously present. We describe a syllabus with eight conceptual modules, each...
Many modern clusters are being equipped with multiple GPUs per node to achieve better compute density and power efficiency. However, moving data in/out of GPUs continues to remain a major performance bottleneck. With CUDA 4.1, NVIDIA has introduced Inter-Process Communication (IPC) to address data movement overheads between processes using different GPUs connected to the same node. State-of-the-art...
We present a highly available system for environments such as stock trading, where high request rates and low latency requirements dictate that service disruption on the order of seconds in length can be unacceptable. After a node failure, our system avoids delays in processing due to detecting the failure or transferring control to a back-up node. We achieve this by using multiple primary nodes which...
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