Topology-Aware Correlated Network Anomaly Event Detection and Diagnosis

For purposes such as end-to-end monitoring, capacity planning, and performance bottleneck troubleshooting across multi-domain networks, there is an increasing trend to deploy interoperable measurement frameworks such as perfSONAR. These deployments expose vast data archives of current and historic measurements, which can be queried using web services. Analysis of these measurements using effective schemes to detect and diagnose anomaly events is vital since it allows for verifying if network behavior meets expectations. In addition, it allows for proactive notification of bottlenecks that may be affecting a large number of users. In this paper, we describe our novel topology-aware scheme that can be integrated into perfSONAR deployments for detection and diagnosis of network-wide correlated anomaly events. Our scheme involves spatial and temporal analyses on combined topology and uncorrelated anomaly events information for detection of correlated anomaly events. Subsequently, a set of ‘filters’ are applied on the detected events to prioritize them based on potential severity, and to drill-down upon the events “nature” (e.g., event burstiness) and “root-location(s)” (e.g., edge or core location affinity). To validate our scheme, we use traceroute information and one-way delay measurements collected over 3 months between the various U.S. Department of Energy national lab network locations, published via perfSONAR web services. Further, using real-world case studies, we show how our scheme can provide helpful insights for detection, visualization and diagnosis of correlated network anomaly events, and can ultimately save time, effort, and costs spent on network management.     

Flame aerosol synthesis of phase-pure monoclinic Y2O3 particles via particle size control

In this study, for the first time, a particle size effect on crystal structure of Y₂O₃ particles was exploited to synthesize phase-pure monoclinic Y₂O₃ particles. In the synthesis process, a precursor aerosol consisting of H₂ fuel gas and precursor droplets passed through an impactor before it entered a flame to form yttria particles. A round-jet impactor was used to remove the large precursor droplets, so that the product Y₂O₃ particles were all smaller than a critical size of approximately 1.5 µm. Due to the particle size effect on crystal structure, the Y₂O₃ particles thus obtained were essentially phase-pure with the monoclinic structure. The result shows that, by using an impactor to alter the particle size distribution, it is possible to control the crystal structure of Y₂O₃ particles while maintaining relatively high synthesis yield.     

Studies on the utilization of stripping voltammetry technique in the detection of high-energy materials

Research and development activities are on in many laboratories to develop methods for detecting energetic materials at the trace level. Production or application of high-energy materials may also contaminate the natural environmental systems. Therefore, development of a simple, portable, and inexpensive device for determining explosives at the trace levels is highly desirable. In this study, a stripping voltammetry technique is used for their analytical determination. The study is conducted in an acetonitrile medium. Optimum conditions are obtained in stripping voltammetry for individual analytes. The stripping voltammetric method is compound-selective and can be used for determining a particular high-energy material in a mixture. In this paper, we report the development of an electro-analytical procedure for detecting conventional energetic materials such as Tetryl, TNT, PETN, RDX, and HMX, using the stripping voltammetric method.     

Random vs. alternating donor-acceptor copolymers: A comparative study of absorption and field effect mobility

The influence of the arrangement of donor and acceptor units in a conjugated copolymer chain on the absorption and field effect mobilities was studied. We synthesized a target random copolymer and compared it with two structurally relevant alternating copolymers, all consisting of 2,1,3-Benzothiadiazole (BT) as acceptor and 3-Hexylthiophene (Th) as donor units. Especially, bifunctional AB-type monomers were developed to obtain the desired randomly linked copolymer r-BT-2Th. We chose AA/BB-type monomers as well to obtain relevant alternating copolymers a-BT-2Th and a-BT-1Th. The systematic structural variation enables us to compare the copolymers in a precise manner. In dilute solutions r-BT-2Th and a-BT-2Th resemble closely in absorption spectra and have similar oxidation potentials regardless of random or alternating arrangement of donor and acceptor. In thin films, a-BT-2Th shows the lowest optical gap and depicts the highest field effect hole mobility of 1.5 × 10⁻³ cm² V⁻¹ s⁻¹.     

Nanoalloying and phase transformations during thermal treatment of physical mixtures of Pd and Cu nanoparticles

Nanoscale alloying and phase transformations in physical mixtures of Pd and Cu ultrafine nanoparticles are investigated in real time with in situ synchrotron-based x-ray diffraction complemented by ex situ high-resolution transmission electron microscopy. The combination of metal–support interaction and reactive/non-reactive environment was found to determine the thermal evolution and ultimate structure of this binary system. At 300 °C, the nanoparticles supported on silica and carbon black intermix to form a chemically ordered CsCl-type (B2) alloy phase. The B2 phase transforms into a disordered fcc alloy at higher temperature (> 450 °C). The alloy nanoparticles supported on silica and carbon black are homogeneous in volume, but evidence was found of Pd surface enrichment. In sharp contrast, when supported on alumina, the two metals segregated at 300 °C to produce almost pure fcc Cu and Pd phases. Upon further annealing of the mixture on alumina above 600 °C, the two metals interdiffused, forming two distinct disordered alloys of compositions 30% and 90% Pd. The annealing atmosphere also plays a major role in the structural evolution of these bimetallic nanoparticles. The nanoparticles annealed in forming gas are larger than the nanoparticles annealing in helium due to reduction of the surface oxides that promotes coalescence and sintering.     

Solution NMR of polypeptides hyperpolarized by dynamic nuclear polarization

Hyperpolarization of nuclear spins through techniques such as dynamic nuclear polarization (DNP) can greatly increase the signal-to-noise ratio in NMR measurements, thus eliminating the need for signal averaging. This enables the study of many dynamic processes which would otherwise not be amenable to study by NMR spectroscopy. A report of solid- to liquid-state DNP of a short peptide, bacitracin A, as well as of a full-length protein, L23, is presented here. The polypeptides are hyperpolarized at low temperature and dissolved for NMR signal acquisition in the liquid state in mixtures of organic solvent and water. Signal enhancements of 300-2000 are obtained in partially deuterated polypeptide when hyperpolarized on (13)C and of 30-180 when hyperpolarized on (1)H. A simulated spectrum is used to identify different resonances in the hyperpolarized (13)C spectra, and the relation between observed signal enhancement for various groups in the protein and relaxation parameters measured from the hyperpolarized samples is discussed. Thus far, solid- to liquid-state DNP has been used in conjunction with small molecules. The results presented here, however, demonstrate the feasibility of hyperpolarizing larger proteins, with potential applications toward the study of protein folding or macromolecular interactions.     

A dynamic reconfigurable routing framework for wireless sensor networks

Sensornet deployments of the future are expected to deliver a multitude of services, ranging from reliable sensing, real time streams, mission critical support, network reprogramming and so on. Naturally, no one routing protocol can sufficiently cater to the network layer functionalities expected. Severe resource constraints further limit the possibility of multiple routing protocols to be implemented. Further, vertically integrated designs of present protocols hinder synergy and code-reuse among implementations. In this paper, we present an architecture that allows applications to send different types of flows, often with conflicting communication requirements. A flow’s requirements are made visible to our framework by using just 3 bits in the packet header. The core architecture is a collection of highly composable modules that allows rapid protocol development and deployment. We show that our framework can provide: (i) flow based network functionality that ensures each flow gets an application specific network layer which is dynamically knit as per the flow’s needs, (ii) modular organization that promotes code-reuse, run time sharing, synergy and rapid protocol development and (iii) pull processing that allows flows to dictate their traffic rate in the network, and implement flexible scheduling policies. This creates a framework for developing, testing, integrating, and validating protocols that are highly portable from one deployment to another. Using our framework, we show that virtually any communication pattern can be described to the framework. We validate this by gathering requirements for one real world application scenario: predictive maintenance (PdM). The requirements are used to generate a fairly complete and realistic traffic workload to drive our evaluation. Using simulations and 40 node MicaZ testbed experiments, we show that our framework can meet the deployments demands at granularities not seen before in sensornets. We measure the costs of using this framework in terms of code size, memory footprints and forwarding costs on MicaZ motes.     

Influence of 1,4-dinitropiperazine (DNP) on the pressure index of rdx containing extruded double base propellants

Abstract

Effect of 1,4-dinitropiperazine (DNP) in bringing down the pressure index (n) in RDX - containing extruded double base propellents has been studied. Experiments have been conducted on two sets of formulations based on controls of low calorimetric value (870 cal/g) and high calorimetric value (1070 cal/g). RDX content was varied between 10 and 20% and DNP content from 2 to 6 parts per 100 parts of the base composition. DNP alone does not bring down n appreciably; however, in conjuction with Basic Lead Salicylate, a well known ballistic modifier (2 parts), it brings down the n in the 70–105 kg/cm² pressure range significantly. The effect is more pronounced in the low calorimetric value compositions and a plateau effect has been observed. Addition of dinitropiperazine does not adversely affect the thermal and chemical stability of the formulations nor their mechanical properties. The temperature sensitivity of burn rate of DNP containing formulations was reduced to 0.21% / °C as compared to that of the control having of 0.32% / °C.     

Design,simulation and performance analysis bio-sensors for the detection of cholera and diarrhea using MEMS technology

Microsystem Technologies - This paper presents two different types of micro channels namely one is cylindrical and the other is rectangular which are designed and simulated using FEM tool for the...     

Design and simulation of fixed–fixed flexure type RF MEMS switch for reconfigurable antenna

Microsystem Technologies - This Paper Presents the design and simulation of RF MEMS switch taken on Microstrip patch antenna loaded with the circular type CSRR. The Tunability of the patch antenna...