A survey of handover algorithms in DVB-H

Digital Video Broadcasting for Handhelds (DVB-H) is a standard for broadcasting IP Datacast (IPDC) services to mobile handheld terminals. Based on the DVB-T standard, DVB-H adds new features such as time slicing, MPE-FEC, in-depth interleavers, mandatory cell id identifier, optional 4K-modulation mode and the use of 5 MHz bandwidth in addition to the usually used 6, 7, or 8 MHz raster. IPDC over DVB-H is proposed for ETSI to complement the DVB-H standard by combining IPDC and DVB-H in an end-to-end system. Handover in such unidirectional broadcasting networks is a novel issue. In the last few years since the birth of DVB-H technology, great attention has been given to the performance analysis of DVB-H mobile terminals. Handover is one of the main research topics for DVB-H in mobile scenarios. Better reception quality and greater power efficiency are considered to be the main targets of handover research for DVB-H. New algorithms for different handover stages in DVB-H have been the subject of recent research and are currently being studied. Further novel algorithms need to be designed to improve the mobile reception quality. This article provides a comprehensive survey of the handover algorithms in DVB-H. A systematic evaluation and categorization approach is proposed based on the problems the algorithms solve and the handover stages being focused on. Criteria are proposed and analyzed to facilitate designing better handover algorithms for DVB-H that have been identified from the research conducted by the author

Algorithms for Replica Placement in High-Availability Storage

A new model of causal failure is presented and used to solve a novel replica placement problem in data centers. The model describes dependencies among system components as a directed graph. A replica placement is defined as a subset of vertices in such a graph. A criterion for optimizing replica placements is formalized and explained. In this work, the optimization goal is to avoid choosing placements in which a single failure event is likely to wipe out multiple replicas. Using this criterion, a fast algorithm is given for the scenario in which the dependency model is a tree. The main contribution of the paper is an $O(n + \rho \log \rho)$ dynamic programming algorithm for placing $\rho$ replicas on a tree with $n$ vertices. This algorithm exhibits the interesting property that only two subproblems need to be recursively considered at each stage. An $O(n^2 \rho)$ greedy algorithm is also briefly reported.Comment: 22 pages, 7 figures, 4 algorithm listing

Improved Charge-Trapping Performance of Hf-Doped SrTiO3 for Nonvolatile Memory Applications

The charge-trapping characteristics of Hf doped SrTiO3 have been studied based on Al/Al2O3/Hf-doped SrTiO3/SiO2/Si capacitors. The thermodynamic stability of the SrTiO3 film is significantly improved by Hf incorporation, thus resulting in negligible formation of an interlayer at the Hf-doped SrTiO3/SiO2 interface, as confirmed by X-ray photoelectron spectroscopy and transmission electron microscopy. The memory device with Hf-doped SrTiO3 as charge-trapping layer displays high speed at low operating voltage (a VFB shift of 1.9 V at +6 V, 100 ms) and good data retention (charge loss of 12.7% after 104 s). Therefore, the Hf-doped SrTiO3 film is a promising material as charge-trapping layer for high-performance nonvolatile memory applications.postprin

Nitrided La 2O 3 as charge-trapping layer for nonvolatile memory applications

Charge-trapping characteristics of La 2O 3 with and without nitrogen incorporation were investigated based on Al/Al 2O 3/La 2O 3/SiO 2Si (MONOS) capacitors. The physical properties of the high-k films were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. Compared with the MONOS capacitor with La 2O 3 as charge-trapping layer, the one with nitrided La 2O 3 showed a larger memory window (4.9 V at ±10-V sweeping voltage), higher program speed (4.9 V at 1-ms +14 V), and smaller charge loss (27% after 10 years), due to the nitrided La 2O 3 film exhibiting less crystallized structure and high trap density induced by nitrogen incorporation, and suppressed leakage by nitrogen passivation. © 2012 IEEE.published_or_final_versio

Microstructure of the deep level defect E1/E2 in 6H silicon carbide (Abstract)

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Charge-Trapping Characteristics of Fluorinated Thin ZrO2 Film for Nonvolatile Memory Applications

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Effects of thermal annealing on La2O3 gate dielectric of InGaZnO thin-film transistor

The effects of thermal annealing on La2O3 gate dielectric of InGaZnO thin-film transistor (TFT) are investigated by varying annealing temperature. Due to densification and enhanced moisture resistance of the La2O3 film, its surface roughness and interface with InGaZnO are improved by the thermal annealing, thus leading to significant improvement in the TFT electrical performance. However, higher-temperature (450 oC) annealing deteriorates the dielectric roughness and induces more traps associated with grain boundaries in the La2O3 film. The TFT with an appropriate annealing (350 oC) shows the best performance with smallest sub-threshold swing (0.276 V/dec), lowest threshold voltage (3.01 V), highest field-effect mobility (23.2 cm2/V.s) and largest on-off current ratio (3.52×108). © 2015 The Electrochemical Society.postprin

Organic diagenesis in sediment and its impact on the adsorption of bisphenol A and nonylphenol onto marine sediment

Hydrophobic organic contaminants in marine water are mostly adsorbed onto (partitioned into) sediment organic matter (SOM). To study the impact of SOM diagenesis on sediment adsorption properties, artificial sediment with rich SOM content was incubated for more than 120. days. The sediment was sampled every week, and batch sediment adsorption tests were conducted with bisphenol A (BPA) and nonylphenol (NP) as the model pollutants. The results show that the amount of organic matter loaded in the sediment decreased by nearly 80% during incubation. For the incubated sediment, the BPA partition coefficient, Kd, decreased whereas the organic normalized partition coefficient, Koc, more than doubled. The experiments with NP show an even greater increase in Koc. Organic matter diagenesis shows a profound effect on the adsorption behavior of sediment, as the SOM residue has an increasing affinity and partition capacity for organic contaminants. © 2010 Elsevier Ltd.postprin

Effects of fluorine incorporation on the electrical properties of silicon MOS capacitor with La2O3 gate dielectric

In this work, the effects of fluorine incorporation by using plasma on the electrical properties of Si MOS capacitor with La2O3 gate dielectric are investigated. From the capacitance-voltage (C-V) curve and gate leakage current, it is demonstrated that the F-plasma treatment can effectively suppress the growth of interfacial layer, and thus improve the electrical properties of the device in terms of accumulation capacitance, interface-state density and breakdown voltage. © 2011 IEEE.published_or_final_versio