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Thyristors working in power converters tend to operate under thermal and environmental stresses which degrade their performance. If the degree of degradation due to such stresses remains undetected at its early stage, then critical processes may lead to unwanted shutdown and consequential economic loss. Work presented in this paper proposes a scheme to monitor the degree of degradation due to thermal...
We demonstrate experimental evidence for non-instantaneous polarization decay in dielectrics. The few-femtosecond relaxation times agree favorable with solutions of the time-dependent Schrödinger equation and relate to resonances of the quantum mechanical dipole.
Dilute GaAsN layers are grown by liquid phase epitaxy technique from a GaAs + Ga + GaN melt with upto 2 mol% Li3N added to the same to act as a flux to promote nitrogen dissolution in Ga. A maximum nitrogen content of 1 at% in the material is obtained as measured by high resolution X-ray diffraction studies. Further 10 K photoluminescence measurements showed a band gap reduction of 145 meV in the...
A new optimization technique named as sliced particle swarm optimization (SPSO) is proposed. It introduces the slicing of search space into rectangular slices. It gives complete solution in terms of reduction in the computational cost and tracking minutely each sliced search space. It introduces the momentum factor which restricts the particle in a sliced search space. Linearly decreasing inertia...
Due to the unattended nature of wireless sensor networks, an adversary can physically capture and compromise sensor nodes and then mount a variety of attacks with these compromised nodes. To minimize the damage incurred by compromised nodes, the system should detect and revoke them as soon as possible. To meet this need, we propose a zone-based node compromise detection and revocation scheme in sensor...
The challenge today is to develop a modeling and simulation paradigm that integrates structural, molecular and genetic data for a quantitative understanding of physiology and behavior of biological processes at multiple scales. This paradigm requires techniques that maintain a reasonable accuracy of the biological process and also reduces the computational overhead. This objective motivates the use...
Data reporting strategy in heterogeneous wireless sensor networks can be differentiated based on task-specific requirements. In this paper, we propose a novel two-phase data reporting (TDR) scheme that supports class-based QoS to sensor nodes in different priority classes. In the first phase, time slots are divided into separate data reporting round defined for each class, while in the second phase,...
Most of geographic forwarding protocols assume that all sensors are always on. Such an assumption is unrealistic for applications where sensors are switched on or off. This paper focuses on k-covered wireless sensor networks (WSNs), where each point in a field is covered by at least k sensors. First, we characterize k-coverage. Then, we propose an energy-efficient scheduling protocol for k-covered...
This study investigates on the laser-induced periodic surface structures (LIPPS) formation in single-crystalline ZnO semiconductors with two distinct types of ripple structures, characterized by the lower and higher spatial frequency LIPPS. Results are shown and interpreted in the frame of a Drude-model including a nonlinear process at the irradiated surface. In addition, results reveal the influence...
ZnOis one of the most promising materials for optoelectronic devices for UV spectral range because of its wide and direct bandgap (3.37 eV) and high exciton binding energy (60 meV). The generation of multiphoton absorption (MPA) induced luminescence in ZnO by highly intense fs-lasers in near infrared offers one effective route for optical excitation. Therefore, much attention has been paid recently...
Sensing coverage reflects the quality of surveillance of a field by a wireless sensor network (WSN). This paper investigates the problem of minimum connected k-coverage in WSNs, where each point in a field is covered (or sensed) by at least k active sensors while minimizing the necessary total number of active sensors and ensuring connectivity between them. In this paper, we propose two k-coverage...
Due to the unattended nature of wireless sensor networks, an adversary can capture and compromise sensor nodes, generate their replicas, and thus mount a variety of attacks with these replicas. Such attacks are dangerous because they allow the attacker to leverage the compromise of a few nodes to exert control over much of the network. Several replica node detection schemes have been proposed in the...
In this paper, we propose an integrated cross-layer data reporting scheme focusing on communication protocols in wireless sensor networks. The scheme operates based on the various application demands and available resources to provide an adaptive quality of service (QoS). The goal of this work is to achieve the expected information quality at the end system by efficiently controlling data reporting...
A number of protocols have been developed to mitigate the threat against wireless sensor networks of an attacker finding nodes, compromising them, and using these nodes to eavesdrop or undermine the operation of the network. A more dangerous threat that has received less attention, however, is that of replica nodes, in which the attacker compromises a node, extracts its keying materials, and produces...
Teleportation is a new and exciting field of future communication. Security in data communication is a major headache now a day. Among the encryption technologies that are available at present, shared key is the most reliable which depends on secure key generation and distribution. Teleportation/entanglement is a perfect solution in this regard as for the no cloning theorem of quantum mechanics any...
On behalf of the organizing committee, we are pleased to present to you the proceedings of the First International Workshop on Information Quality and Quality of Service for Pervasive Computing, IQ2S 2009. The workshop is the first in a series intended to the creation of a forum to exchange ideas, present results, share experience, and enhance collaborations among researchers, professionals, and application...
In this paper, asynchronous sampling is proposed as a novel approach to improve the information quality of sensory data through shifting the sampling moments of sensors from each other. The exponential correlation model and the entropy model for the sensory data are introduced to quantify their information quality. An asynchronous sampling strategy, EASS, is presented accordingly to assign equal time...
The term entanglement is used in quantum theory to describe the way that particles of energy/matter can become correlated and predictably interact with each other regardless of how far apart they are. In future quantum entanglement will dominate the way we look at information, the way we communicate secretly and the way our computers do their things. Much current research is focusing on how to harness...
Ubiquitous (or smart) healthcare applications envision sensor rich computing and networking environments that can capture various types of contexts of patients (or inhabitants of the environment), such as their location, activities and vital signs. Such context information is useful in providing health related and wellness management services in an intelligent way so as to promote independent living...
Angularly and spectrally resolved second harmonic studies for c-axis ZnO nanorods are reported. 7.5 times higher efficiency than for BBO was found at 55 GW/cm2 at Ti:sapphire laser oscillator wavelengths. Spectral profiles agree with simulations.
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