Optimal size-based opportunistic scheduler for wireless systems

Modern wireless cellular systems are able to utilize the opportunistic scheduling gain originating from the variability in the users’ channel conditions. By favoring users with good instantaneous channel conditions, the service capacity of the system can be increased with the number of users. On the other hand, for service systems with fixed service capacity, the system performance can be optimized by utilizing the size information. Combining the advantages of size-based scheduling with opportunistic scheduling gain has proven to be a challenging task. In this paper, we consider scheduling of data traffic (finite-size elastic flows) in wireless cellular systems. Assuming that the channel conditions for different users are independent and identically distributed, we show how to optimally combine opportunistic and size-based scheduling in the transient setting with all flows available at time 0. More specifically, by utilizing the time scale separation assumption, we develop a recursive algorithm that produces the optimal long-run service rate vectors within the corresponding capacity regions. We also prove that the optimal operating policy applies the SRPT-FM principle, i.e., the shortest flow is served with the highest rate of the optimal rate vector, the second shortest with the second highest rate, etc. Moreover, we determine explicitly how to implement the optimal rate vectors in the actual time slot level opportunistic scheduler. In addition to the transient setting, we explore the dynamic case with randomly arriving flows under illustrative channel scenarios by simulations. Interestingly, the scheduling policy that is optimal for the transient setting can be improved in the dynamic case under high traffic load by applying a rate-based priority scheduler that breaks the ties based on the SRPT principle.     

Lateral beam shift at transmission through layered structures with negative index material

We studied electromagnetic wave transmission through layered structures that include negative index materials. The excitation of leaky guided modes leads to the formation of anomalous lateral shifts in the reflected beam with a double-peak structure and in the transmitted beam with a single-peak structure. In the absence of losses, we demonstrate that the total transparency (i.e. zero reflection) of the slab waveguide with the negative index material can be achieved under conditions in which high reflectivity is normally expected. We demonstrate the trade-off effect between the high transmission and the high lateral shift. This peculiar effect exists not only for the pure TE or the pure TM polarization of the obliquely incident radiation, but also under certain circumstances for both of them simultaneously i.e. for the nonpolarized radiation.     

Systematic generation of higher-order solitons and breathers of the Hirota equation on different backgrounds

In almost all real-world application such as electric vehicles, system outputs are corrupted by various types of noises. Although the sliding mode controller is a popular controller in the electrical vehicle applications, it is vulnerable to the noisy signals, and even intensify its unwilling effects. In this paper, to eliminate process noise and stabilize the vehicle in noisy conditions, a minimum variance controller is utilized. It is shown that this controller is able to decrease the system output variance, optimally. Besides, it can track yaw rate and velocity reference inputs. Also stability condition is reached. Furthermore, decreasing control signal variance along with output variance is studied in this paper. Finally, the proposed approach is compared with sliding mode controller in noisy condition on four wheel drive electric vehicle which is simulated in MATLAB and CARSIM environments.     

A lab-on-a-chip compatible bioaffinity assay method for human alpha-fetoprotein

A new lab-on-a-chip compatible binding assay platform is introduced. The platform combines dry-chemistry bioaffinity reagents and the recently introduced ArcDia TPX binding assay technique. The technique employs polymer microspheres as a solid phase reaction carrier, fluorescently labeled antibody conjugates, and detection of fluorescence emission from the surface of individual microspheres by two-photon excitation fluorescence. Signal response of the technique is independent of the reaction volume, thus the technique is particularly well suited for detection of bioaffinity reactions from miniature volumes. Performance of the new assay platform is studied by means of an immunometric assay of human alpha-fetoprotein (hAFP) in 384-plate format, and the results are compared to those of a corresponding wet-chemistry assay method. The results show that the ArcDia TPX detection technique can be combined with dry-chemistry reagents without compromises in assay performance. The microchip field has so far been characterized with a lack of microchip-compatible detection platforms which would allow cost-effective microchip design and sensitive bioaffinity detection. The presented detection technique is expected to provide a solution for this shortage.     

Metal-ligand interplay in strongly correlated oxides: a parametrized phase diagram for pressure-induced spin transitions

We investigate the magnetic properties of archetypal transition-metal oxides MnO, FeO, CoO, and NiO under very high pressure by x-ray emission spectroscopy at the Kbeta line. We observe a strong modification of the magnetism in the megabar range in all the samples except NiO. The results are analyzed within a multiplet approach including charge-transfer effects. The spectral changes are well accounted for by changes of the ligand field acting on the d electrons and allows us to extract the d-hybridization strength, O-2p bandwidth and ionic crystal field across the magnetic transition. This approach allows first-hand insight into the mechanism of the pressure-induced spin transition.     

In vivo MRI reveals the dynamics of pathological changes in the brains of cathepsin D-deficient mice and correlates changes in manganese-enhanced MRI with microglial activation

Cathepsin D (CTSD; EC 3.4.23.5) is essential for normal development and/or maintenance of neurons in the central nervous system: its deficiency causes a devastating neurological disorder with severely shortened life span in man, sheep and mouse. Neuropathologically, the CTSD deficiencies are characterized by selective neuronal degeneration, gliosis and accumulation of autofluorescent proteinaceous storage material in neurons. Our aim was to study the dynamics behind the pathological alterations occurring in the brains of CTSD-deficient (CTSD-/-) mice by using in vivo magnetic resonance imaging (MRI) and histology. In order to do this, we measured T(2) signal intensity (SI), apparent diffusion coefficient, area and volume of multiple brain structures from MR images acquired using T(2)-, T(1)- and diffusion-weighted sequences at three time points during disease progression. MRI revealed no differences in the brains between CTSD-/- and control mice at postnatal day 15+/-1 (P15+/-1), representing an initial stage of the disease. In the intermediate stage of the disease, P19(+/-1), SI alterations in the thalami of the affected mice became evident in both T(1)- and T(2)-weighted images. The terminal stage of the disease, P25, was characterized by marked alterations in the T(2) SI, apparent diffusion coefficient and volume of multiple brain structures in CTSD-/- mice. In addition, manganese enhanced high-resolution T(1)-weighted 3D sequences (MEMRI) and histological stainings revealed that the hyperintense signal areas in MEMRI matched perfectly with areas of microglial activation in the brains of CTSD-/- mice at the terminal disease stage. In conclusion, the SI alterations in the thalami of CTSD-/- mice preceded other changes, and the degenerative process was greatly enhanced at the age P19(+/-1), leading to severely reduced brain volume in just 6 days.     

Breathers,solitons and rogue waves of the quintic nonlinear Schrödinger equation on various backgrounds

Nonlinear Dynamics - We investigate the generation of breathers, solitons, and rogue waves of the quintic nonlinear Schrödinger equation (QNLSE) on uniform and elliptical backgrounds. The...