Fast network configuration in Software Defined Networking

Software Defined Networking (SDN) provides a framework to dynamically adjust and re-program the data plane with the use of flow rules. The realization of highly adaptive SDNs with the ability to respond to changing demands or recover after a network failure in a short period of time, hinges on efficient updates of flow rules. We model the time to deploy a set of flow rules by the update time at the bottleneck switch, and formulate the problem of selecting paths to minimize the deployment time under feasibility constraints as a mixed integer linear program (MILP). To reduce the computation time of determining flow rules, we propose efficient heuristics designed to approximate the minimum-deployment-time solution by relaxing the MILP or selecting the paths sequentially. Through extensive simulations we show that our algorithms outperform current, shortest path based solutions by reducing the total network configuration time up to 55% while having similar packet loss, in the considered scenarios. We also demonstrate that in a networked environment with a certain fraction of failed links, our algorithms are able to reduce the average time to reestablish disrupted flows by 40%

Microwave (EPR) measurements of the penetration depth measurements of high-Tc superconductors

The use is discussed of electron paramagnetic resonance (EPR) as a quick and easily accessible method for measuring the London penetration depth, lambda for the high T sub c superconductors. The method uses the broadening of the EPR signal, due to the emergence of the magnetic flux lattice, of a free radical adsorbed on the surface of the sample. The second moment, of the EPR signal below T sub c is fitted to the Brandt equation for a simple triangular lattice. The precision of this method compares quite favorably with those of the more standard methods such as micro sup(+)SR, neutron scattering, and magnetic susceptibility

Amalan pengurusan keselamatan bengkel kemahiran hidup (KHB) Sekolah Menengah Harian Daerah Batu Pahat

Kajian ini dijalankan untuk mengkaji sejauhmanakah persepsi pelajar terhadap amalan pengurusan keselamatan dari aspek keselamatan alatan dan bahan, diri dan rakan serta keselamatan am di bengkel Kemahiran Hidup sekolah menengah harian daerah Batu Pahat. Kajian berbentuk kuantitatif dilaksanakan di empat buah sekolah menengah harian daerah Batu Pahat iaitu SMK Datin Onn Jaafar, SMK Banang Jaya, SMK Dato Onn dan SMK Seri Gading. Sampel kajian terdiri daripada 350 orang pelajar tingkatan dua yang mengambil matapelajaran KHB dan data dikumpul menggunakan instrumen borang soal selidik. Dapatan kajian dianalisis menggunakan perisian Winsteps Version 3.69.1.11 dengan pendekatan Model Pengukuran Rasch sepenuhnya. Data dianalisis menggunakan teknik analisis diskriptif dan analisis inferensi iaitu ujian-t bagi menguji hipotesis kajian. Dapatan kajian menunjukkan bahawa amalan pengurusan keselamatan di bengkel diamalkan secara sederhana bagi ketiga-tiga aspek tersebut. Terdapat perbezaan yang signifikan di antara pelajar di bandar dan luar bandar iaitu t=-4.08 dan p=0.000 di mana nilai min ukuranya pula ialah -.19. Beberapa cadangan telah dikemukakan bagi penambahbaikkan seperti mengadakan kempen kesedaran dan menyediakan sudut standard operasi amalan pengurusan keselamatan agar pelajar sentiasa mematuhi peraturan semasa berada di bengkel Kemahiran Hidup

Tunable near- to mid-infrared pump terahertz probe spectroscopy in reflection geometry

Strong-field mid-infrared pump--terahertz (THz) probe spectroscopy has been proven as a powerful tool for light control of different orders in strongly correlated materials. We report the construction of an ultrafast broadband infrared pump--THz probe system in reflection geometry. A two-output optical parametric amplifier is used for generating mid-infrared pulses with GaSe as the nonlinear crystal. The setup is capable of pumping bulk materials at wavelengths ranging from 1.2 $\mu$m to 15 $\mu$m and beyond, and detecting the subtle, transient photoinduced changes in the reflected electric field of the THz probe at different temperatures. As a demonstration, we present 15 $\mu$m pump--THz probe measurements of a bulk EuSbTe$_{3}$ single crystal. A $0.5\%$ transient change in the reflected THz electric field can be clearly resolved. The widely tuned pumping energy could be used in mode-selective excitation experiments and applied to many strongly correlated electron systems.Comment: 4 pages, 4 figure

Effect of magnetic field on the velocity autocorrelation and the caging of particles in two-dimensional Yukawa liquids

We investigate the effect of an external magnetic field on the velocity autocorrelation function and the "caging" of the particles in a two-dimensional strongly coupled Yukawa liquid, via numerical simulations. The influence of the coupling strength on the position of the dominant peak in the frequency spectrum of the velocity autocorrelation function confirms the onset of a joint effect of the magnetic field and strong correlations at high coupling. Our molecular dynamics simulations quantify the decorrelation of the particles' surroundings - the magnetic field is found to increase significantly the caging time, which reaches values well beyond the timescale of plasma oscillations. The observation of the increased caging time is in accordance with findings that the magnetic field decreases diffusion in similar systems

Measurement of NO2 indoor and outdoor concentrations in selected public schools of Lahore using passive sampler

Higher levels of NO2 are a danger to human health especially for children. A seven day study was carried to find out the ambient concentrations of NO2in 27 schools of Lahore with the help of passive samplers. In each school three sites were selected, viz: laboratory, corridor and outdoors. After 7 days exposure the tubes were subjected to spectrophotometric analysis. Results showed that the maximum values measured in laboratory, outdoor and corridors were 376µg/m3 , 222µg/m3 and 77µg/m3 . Minimum values for laboratory, outdoor and corridors were 10µg/m3 , 20µg/m3 and 8µg/m3 . Factors affecting these values were laboratory activities and proximity to main roads. These values were significantly higher than the standard values defined by EPA. Therefore children in schools were at risk of developing health complications