Advanced modulation formats combined with digital signal processing and direct detection is a promising way to realize high capacity, low cost and power efficient short reach optical transmission system. In this paper...
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Advanced modulation formats combined with digital signal processing and direct detection is a promising way to realize high capacity, low cost and power efficient short reach optical transmission system. In this paper, we have studied and compared several advanced modulation formats in terms of performance and implementation complexity for 100Gb/s/lambda short reach transmission systems.
Multi Query Optimization in federated database systems is a well-studied area. Studies have shown that similar problem arises in wide range of applications, e.g., distributed stream processing systems and wireless sen...
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ISBN:
(纸本)9781509002887
Multi Query Optimization in federated database systems is a well-studied area. Studies have shown that similar problem arises in wide range of applications, e.g., distributed stream processing systems and wireless sensor networks. In this paper, a general distributed multiquery processing problem motivated by the need to speedup data acquisition in federated databases using evolutionary algorithm is studied. We setup a simple framework in which each individual in population is evolved in terms of cost, uniform labeling of hyper edges and validity of resource constraints through a number of generations. Variations of our general problem can be shown to be NP-Hard. Our extensive empirical evaluation over five different synthetic datasets shows a significant improvement of 8 percent in results as compared to the state-of-the-art methods.
Cross-phase modulation (XPM) induced by the lower rate on-off keying (OOK) channels has been considered as the main impairment on quadrature phase shift keying (QPSK) channels in hybrid wavelength division multiplexed...
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ISBN:
(纸本)9781467373746
Cross-phase modulation (XPM) induced by the lower rate on-off keying (OOK) channels has been considered as the main impairment on quadrature phase shift keying (QPSK) channels in hybrid wavelength division multiplexed (WDM) optical coherent systems. We extend a linear IM/XPM model for XPM by considering the nonlinear effects induced by dispersion compensation fibers (DCF) in dispersion compensated optical links. From such a model we estimate the variance of the XPM induced nonlinear phase noise. the bit error rate (BER) is provided for QPSK signal contaminated by both XPM and ASE induced phase noise. the extended model and the analytical expressions show a good agreement with Monte-Carlo (MC) simulations. Simulation results also show that the XPM contributions of the DCFs impact the IM/XPM filter amplitude and the performance of the dispersion compensation system.
Cooperative behavior is vital to Cognitive Radio networks (CRN), which has the distributed nature. Time synchronization is the basic to cooperation. Many protocols are developed. However, they are either rather compli...
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ISBN:
(纸本)9781467372916
Cooperative behavior is vital to Cognitive Radio networks (CRN), which has the distributed nature. Time synchronization is the basic to cooperation. Many protocols are developed. However, they are either rather complicated or relying on infrastructure such as GPS. In this paper, a physical layer approach is proposed. Without complex protocols and not reliable to other systems, this approach has a better efficiency. the synchronization method is proposed and the corresponding platform is demonstrated. the analysis on how the error of synchronization deteriorates the performance is given and the solutions are shown thereafter.
We consider the fundamental problem of managing a bounded size queue buffer where traffic consists of packets of varying size, each packet requires several rounds of processing before it can be transmitted out, and th...
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ISBN:
(纸本)9781479936359
We consider the fundamental problem of managing a bounded size queue buffer where traffic consists of packets of varying size, each packet requires several rounds of processing before it can be transmitted out, and the goal is to maximize the throughput, i.e., total size of successfully transmitted packets. Our work addresses the tension between two conflicting algorithmic approaches: favoring packets with fewer processing requirements as opposed to packets of larger size. We present a novel model for studying such systems and study the performance of online algorithms that aim to maximize throughput.
For several years were actively developing solutions for creation regional cross-border gateways that allowed to implement high performance, reliable and effective connections between national scientific - educational...
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For several years were actively developing solutions for creation regional cross-border gateways that allowed to implement high performance, reliable and effective connections between national scientific - educational networks in the East Europe. Created and proposed for implementation connections are used for providing access of regional NRENs to Trans-European academic infrastructure GEANT (the pan-European data network for the research and education community). However, external optical gateways without developed internal connectivity at national level cannot solve the main problem - to provide high speed and cost effective access for end users to GEANT resources and services. To eliminate the existing misbalance in the networking infrastructure in RENAM was elaborated a project of national optical networking backbone upgrading. the project is focusing on transferring internal backbone to utilization of modern routing and switching equipment that will allow implementing new communication technologies. Upgraded optical infrastructure will significantly improve access to the wide range of GEANT network services and resources for national users' communities.
Withthe growing deployment of host and network intrusion detection systems in increasingly large and complex communicationnetworks, managing low-level events from these systems becomes critically important. A networ...
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Withthe growing deployment of host and network intrusion detection systems in increasingly large and complex communicationnetworks, managing low-level events from these systems becomes critically important. A network has multiple tasks, which consist of multiple network services aiding the execution of a task. An emerging track of security research has focused on event prioritization and correlation to rank the criticality of events and reduce the number of low-level events. To prioritize and correlate events, the ongoing tasks in an enterprise network are identified, as the goal of network operators is to protect ongoing tasks when a security breach occurs. the prioritization of an event depends on the criticality of an ongoing task that is potentially threatened by the event. Additionally, in order to support network operators, we correlate all events that target the same task. A particular task may depend on multiple network services and involve multiple network devices. So, if one network service becomes unavailable, other network services will be affected over time since they Unfortunately, dependency details are often not documented and are difficult to discover by relying on human expert knowledge. In order to solve this problem, a network dependency analysis based on network traffic is conducted. We rely on pattern mining techniques to discover tasks in a monitored enterprise network. A formal description of the identified tasks is provided and events are prioritized and correlated based on this model. the pattern mining based network dependency analysis algorithm is evaluated based on a real-world network and three networksthat where created with a network simulator.
Delay variation or jitter is an inherent feature of packet switched communicationnetworks due to bottlenecks. In communicationsystems buffering is commonly used to mitigate in real time multimedia applications at th...
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ISBN:
(纸本)9781479977321
Delay variation or jitter is an inherent feature of packet switched communicationnetworks due to bottlenecks. In communicationsystems buffering is commonly used to mitigate in real time multimedia applications at the expense of an additional delay. this method is therefore not suitable for control systems implemented over packet switched communicationnetworks due to the additional delay which can make the system unstable. Hence, jitter modelling and management is necessary. this paper focuses on the development and experimental verification of a suitable jitter model for wireless and wired network bottlenecks. the effects of jitter are then investigated by quantifying the performance of a simulated Networked Control System (NCS). According to the results, the reduction in attenuation due to jitter compared to a jitter free benchmark ranges from approximately 0.01-0.04dB depending on the encoding type.
A computational study is conducted to evaluate the hypothesis that mate selection is the evolutionary origin of communication. A population of neural networks is evolved for two cooperative tasks - mate selection and ...
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ISBN:
(纸本)9780262326216
A computational study is conducted to evaluate the hypothesis that mate selection is the evolutionary origin of communication. A population of neural networks is evolved for two cooperative tasks - mate selection and prey capture. Simple codes developed for mate selection serve as an effective stepping stone for prey capture but not vice versa. Mate selection followed by an additional prey capture task is also easier to evolve than both together from the beginning. this result suggests that mate selection may be a first step in the evolution of general communicationsystems in nature.
the proceedings contain 24 papers. the topics discussed include: automatic transport selection and resource allocation for resilient communication in decentralized networks;reducing costs in the personal cloud: is Bit...
ISBN:
(纸本)9781479962013
the proceedings contain 24 papers. the topics discussed include: automatic transport selection and resource allocation for resilient communication in decentralized networks;reducing costs in the personal cloud: is BitTorrent a better bet?;decentralizing the cloud: how can small data centers cooperate;diversity entails improvement: a new neighbor selection scheme for kademlia-type systems;RankSlicing: a decentralized protocol for supernode selection;on the tradeoff between resilience and degree overload in dynamic p2p graphs;user freedom: to be or not to be a supernode;routing table construction method solely based on query flows for structured overlays;stochastic models of pull-based data replication in p2p systems;replicated erasure codes for storage and repair-traffic efficiency;and cloudy knapsack problems: an optimization model for distributed cloud-assisted systems.
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