We present results of an acquisition of Terahertz imaging and its analysis in terms of frequency based on a Time Domain Terahertz Spectroscopy system. THz radiation was generated using a photoconductive antenna based ...
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ISBN:
(纸本)9781424458547
We present results of an acquisition of Terahertz imaging and its analysis in terms of frequency based on a Time Domain Terahertz Spectroscopy system. THz radiation was generated using a photoconductive antenna based on LT-GaAs and was detected by the electro-optical sampling in a ZnTe crystal. Broadband THz pulses were obtained in the range from 0.1 THz to 4 THz, with a peak intensity at 1 THz. The full transmission spectrum for different materials was measured, and frequency-dependent imaging characteristics were analyzed.
All-optical wavelength conversion is investigated using fourwave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the co...
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ISBN:
(纸本)9781849193146
All-optical wavelength conversion is investigated using fourwave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the conversion efficiency and phase-matching condition are analyzed. The conversion bandwidth is tempted to enhance by optimizing the waveguide geometry and using the two-pump regime. And finally an angled-polarization pump is used to realize the polarization-independent wavelength conversion by eliminating the polarization discrepancy between the TE and TM modes.
As networks develop into large-scale systems, survivability of network systems is imperative. The systematic metrics of network survivability are used to measure or evaluate network survivability. This Paper summarize...
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In ICC2008 and subsequent work, Lei et al. proposed a user authentication system (virtual password system), which is claimed to be secure against identity theft attacks, including phishing, keylogging and shoulder sur...
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In ICC2008 and subsequent work, Lei et al. proposed a user authentication system (virtual password system), which is claimed to be secure against identity theft attacks, including phishing, keylogging and shoulder surfing. Their authentication system is a challenge-response protocol based on a randomized linear generation function, which uses a random integer in the responses of each login session to offer security against assorted attacks. In this paper we show that their virtual password system is insecure and vulnerable to multiple attacks. We show that with high probability an attacker can recover an equivalent password with only two (or a few more) observed login sessions. We also give a brief survey of the related work and discuss the main challenges in designing user authentication methods secure against identity theft.
Cluster-Head (CH) nodes function as gateways between the sensors and the Base Station, in Wireless Sensor Networks with a cluster hierarchy. The total energy dissipation of the sensors can be reduced by optimizing the...
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Cluster-Head (CH) nodes function as gateways between the sensors and the Base Station, in Wireless Sensor Networks with a cluster hierarchy. The total energy dissipation of the sensors can be reduced by optimizing the load balance within the cluster hierarchy. This paper proposes an uncapacitated facility location based cluster scheme in which the system lifetime is extended by adding an additional layer of SuperCluster-Head (SCH) nodes, in order to ease the transmission load of the CHs and to balance the load distribution within the network. The SCH layer is configured using an uncapacitated facility location algorithm in which the facility and service costs are defined in terms of both the energy and the transmission distance. The simulation results confirm that the proposed method yields a better load balance in the SCH layer than that obtained using either a random configuration or a round-robin scheme. Finally, it is shown that irrespective of the size of the sensor field, the proposed scheme outperforms the conventional LEACH-C two-layer scheme in terms of the average energy dissipation of the nodes, the average survival times of the nodes, and the overall system lifetime.
A mathematical model is established, centered on time efficiency andimproved, Ant Colony Algorithm. Ant Colony Algorithm, is used, to solve theemergency resources distribution problem, and, several aspects of the algo...
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The multiple pattern matching has always been a significant principle for applying to a network security system. This principle is adapted to accommodate the target patterns to be detected in a pre-processing phase, a...
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ISBN:
(纸本)9781424469611
The multiple pattern matching has always been a significant principle for applying to a network security system. This principle is adapted to accommodate the target patterns to be detected in a pre-processing phase, and the objective text and the suspect patterns are simultaneously detected by comparing with the existing structure. This research article introduces a new algorithm of multi-string pattern matching by means of a new data structure called inverted lists. The inverted lists structure, inherited from the inverted index, is represented by the positions of characters which appear in the patterns. The new algorithm, which is more efficient time than the traditional algorithms, scans the given text in a single pass. More importantly, the structure of patterns is able to update the patterns over time.
Sharing communications are not easy to do in the mobility networks (MONETs) for the limited bandwidth and the overhead of tunneling. Multicast is an intuitive method to solve this problem. To improve the performance, ...
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ISBN:
(纸本)9781424455652
Sharing communications are not easy to do in the mobility networks (MONETs) for the limited bandwidth and the overhead of tunneling. Multicast is an intuitive method to solve this problem. To improve the performance, the multicast topology should be redesigned for the MONETs. We proposed an efficient communication algorithm with multicast schemes in a network mobility (NEMO) environment. The Mobile Router Forwarding Scheme (MRFS) algorithm is proposed for this goal. We can find that MRFS can reduce the storage cost for every Mobile Router (MR) especially in the TLMR (Top level MR).
In this work we present a general control scheme for the management of an energy community and a load modeling approach. We adopt a multilevel control scheme in which the first level computes the energy consumption se...
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In this work we present a general control scheme for the management of an energy community and a load modeling approach. We adopt a multilevel control scheme in which the first level computes the energy consumption set point towards the second level and the generation planning towards the energy sources, the second level is in charge of local loads scheduling and micro-generation planning.
Sensor network terminals are installed in large numbers in the field and transmit data periodically by radio. Such terminals must be miniaturized, and save power so that each device can operate by battery for several ...
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