Clock synchronization is one of the most basic building blocks for many applications in a distributed system. Synchronized clocks are interestingly important because they can be used to improve performance of a distri...
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ISBN:
(纸本)9781467345286
Clock synchronization is one of the most basic building blocks for many applications in a distributed system. Synchronized clocks are interestingly important because they can be used to improve performance of a distributed system. The purpose of clock synchronization is to provide the constituent parts of a distributed system with a common notion of time. There are several algorithms for maintaining clock synchrony in a distributed multiprocessor system where each processor has its own clock. In this paper we consider the problem of clock synchronization with bounded clock drift. We propose a clock synchronization algorithm which does a two level synchronization to synchronize the local clocks of the nodes and also it exhibits fault tolerant behavior. Our algorithm is a combination of external clock synchronization and internal clock synchronization.
Collaborative document authoring between geographically distributed users is increasingly common in our professional and personal lives. Corresponding systems aim to allow for the involvement of locally unavailable sp...
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ISBN:
(纸本)9781538625651
Collaborative document authoring between geographically distributed users is increasingly common in our professional and personal lives. Corresponding systems aim to allow for the involvement of locally unavailable specialists while connecting familiar single-user functionality with an accessible, distributed multi-user environment. However, considering the highly dynamic processing loads on modern machines, accounting for network inadequacies, and providing a user-adjustable, mainly interruption-free work environment still presents some challenges. To address these challenges, we integrated our fine-granular data model, concurrency-based command application, and data-type specific consistency management into a distributed authoring environment. The collaboration environment provides individual sites sufficient independence to allow the local users to adapt their work experience based on personal preference and other, machine-related factors. This paper discusses our approach for a responsive, yet unobtrusive and adaptable distributed compound document authoring environment with the focus on concurrent and mainly autonomous command application and consistency management.
In this paper we discuss about our new clustering algorithm (ALEC) by modeling the CH and non CH nodes during set-up and steady-state phases of the algorithm. We investigate the effects of event sensing reliability an...
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ISBN:
(纸本)9781479932474;9780769550237
In this paper we discuss about our new clustering algorithm (ALEC) by modeling the CH and non CH nodes during set-up and steady-state phases of the algorithm. We investigate the effects of event sensing reliability and number of clusters on the network lifetime. We also analyze the power consumption and delay overheads of the clustering algorithm. According to the results, energy consumption overhead and delay overhead of ALEC algorithm in worst cases are very low (overhead of power consumption is about 0.06% and overhead of delay is about 0.001%.). The results also show that longer network lifetime can be achieved by both lower values of number of clusters and sensing reliability.
The ongoing convergence of cloud computing and the IoT gives rise to the proliferation of diverse, large-scale IoT and mobile cloud systems. Such novel IoT cloud systems offer numerous advantages for all involved stak...
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ISBN:
(纸本)9781479989775
The ongoing convergence of cloud computing and the IoT gives rise to the proliferation of diverse, large-scale IoT and mobile cloud systems. Such novel IoT cloud systems offer numerous advantages for all involved stakeholders. However, due to scale, complexity, and inherent geographical distribution of such systems, governing new IoT cloud resources poses numerous challenges. In this paper we introduce rtGovOps, a novel framework for on-demand runtime operational governance of software-defined IoT cloud systems. To illustrate the feasibility of our framework and its practical applicability to implement and execute operational governance processes in large-scale software-defined IoT cloud system, we evaluate our approach using a realworld case study on managing fleets of electric vehicles.
This paper proposes a MAC protocol for enhancing the throughput in underwater acoustic sensor networks. Since the transmission speed of acoustic wave is much slower than that of radio, the propagation delay in the wat...
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ISBN:
(纸本)9781479932474;9780769550237
This paper proposes a MAC protocol for enhancing the throughput in underwater acoustic sensor networks. Since the transmission speed of acoustic wave is much slower than that of radio, the propagation delay in the water is much longer. For solving the long propagation delay and hidden terminal problems, the throughput may become very low. To improve the throughput, this paper proposes an algorithm to increase the communications by using some resources which are originally idle for protecting communication from interference. The proposed protocol is based on synchronized technologies. Performance study reveals that the proposed protocol outperforms existing work in terms of network throughput and waiting time of nodes.
In response to the demands and harsh conditions of underwater environments, developing sensor networks and underwater Internet of Things (IoT) has paved the way for wireless communication, ocean exploration, and vario...
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Challenge of graceful migration through upgrades and updates is a daunting task for process control systems. Issues confronted include aging hardware and software, as well as shortage of process experts with knowledge...
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ISBN:
(纸本)9781538662274
Challenge of graceful migration through upgrades and updates is a daunting task for process control systems. Issues confronted include aging hardware and software, as well as shortage of process experts with knowledge of vintage control systems. We offer techniques and solutions for graceful evolution to current generation control system. Our approach covers entire system including HMI, Controller, I/O and Field Interface Layers. We showcase stepwise implementation approach while addressing the concerns. We also provide cost-benefit analysis and pre-requisites for choosing specific evolution path.
Stream processing is emerging to react to the changing business situations of real-time processing. The main aim of this paradigm is to deal with the huge volume of data in the format of information flows originating ...
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ISBN:
(纸本)9781538625880
Stream processing is emerging to react to the changing business situations of real-time processing. The main aim of this paradigm is to deal with the huge volume of data in the format of information flows originating from distributed devices. This consequently poses challenges to the scheduling problem in cloud data centers regarding the time-varying velocity of data ingesting and processing. In response to the uncertainties and complexities of streaming data, we propose a model-based scheduling scheme for stream processing systems, capturing the system behavior and providing an optimal allocation strategy to adapt to the changing work conditions. The proposed scheduling policy is implemented in Apache Storm, and micro-benchmarks with various shapes (e.g line, star, and diamond) were used in the evaluation. A topology that tracks trending topics on Twitter is also used, where the input is feeding with tweets in realtime. Experimental results show that the proposed solution can perform estimations that are well aligned with the system performance. The proposed scheduling policy achieves an improved performance with regards throughput and latency under varying ingesting rates.
With the onset of the Internet the perception of computingsystems in general has revolutionised. Areas of research have migrated from developing nodes to building networks - thus requiring the need for a variety of i...
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ISBN:
(纸本)0780390946
With the onset of the Internet the perception of computingsystems in general has revolutionised. Areas of research have migrated from developing nodes to building networks - thus requiring the need for a variety of information processing techniques, such as clustering, classification, dependency modelling and others. However, the applications of sensor Networks are yet to evolve in such proportions. Some of the primary constraints being the resources available in an embedded environment, the need to dynamically configure services to carry out a variety of tasks, communication interfaces and sensing and monitoring techniques. This paper discusses a holonic analysis to aid in mitigating ill-structured and often problematic situations that, are often characterized by uncertainty in reasoning and the varying nature of relationships with associated elements. The proposed methodology is a synergy between the classic model derived from Soft systems Methodology (SSM) and the model of Systemic Analysis through Familiar Entities (SAFE). Development of an Intelligent Security System (ISS) has been considered to be an ideal test-bed for this synergy to go through the phases of problem definition and exploration, development of conceptual models and generation of insight to stimulate acceptable and feasible changes. The technical aspect of this system encompasses the mode of query processing and surveillance through a structured sensor network set up with the aid of distributed services and network protocols.
Wireless sensor Networks (WSNs) pose novel challenges compared with traditional networks. To answer such challenges a new communication paradigm, data-centric communication, is emerging. One form of data-centric commu...
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ISBN:
(纸本)9781424417964
Wireless sensor Networks (WSNs) pose novel challenges compared with traditional networks. To answer such challenges a new communication paradigm, data-centric communication, is emerging. One form of data-centric communication is the publish/subscribe messaging system. Compared with other data-centric variants, publish/subscribe systems are common and wide-spread in distributedcomputing. Thus, extending publish/subscribe systems into WSNs will simplify the integration of sensor applications with other distributed applications. This paper describes MQTT-S [1], an extension of the open publish/subscribe protocol Message Queuing Telemetry Transport (MQTT) [2] to WSNs. MQTT-S is designed in such a way that it can be run on low-end and battery-operated sensor/actuator devices and operate over band width-constraint WSNs such as ZigBee-based networks. Various protocol design points are discussed and compared. MQTT-S has been implemented and is currently being tested on the IBM wireless sensor networking testbed [3]. Implementation aspects, open challenges and future work are also presented.
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