Efficient motion vector prediction algorithm using pattern matching

The state-of-the-art median prediction scheme is widely used for predicting motion vectors (MVs) in recent video standards. By exploiting the spatial correlations among MVs, median prediction scheme predicts MV for current block from three neighboring blocks. When MV is obtained from motion estimation, MV difference (MVD) is calculated and then transmitted. This process for predicting MV and calculating MVD is known as MV coding process. For MV coding, the performance depends on how efficient both the spatial and the temporal correlations among MVs are being exploited. Median prediction scheme applies a sophisticated way including some special rules to exploit the spatial correlations, however the temporal correlations among successive MVs are not exploited. In this paper, a new algorithm named MV pattern matching (MV-PM) exploiting both the spatial and temporal correlations is proposed. Various kinds of experimental results show that the proposed MV-PM algorithm outperforms the median prediction and the other related prediction schemes.     

A 54×54-b regularly structured tree multiplier

A 54-b×54-b parallel multiplier was implemented in 0.88-μm CMOS using the new, regularly structured tree (RST) design approach. The circuit is basically a Wallace tree, but the tree and the set of partial-product-bit generators are combined into a recurring block which generates seven partial-product bits and compresses them to a pair of bits for the sum and carry signals. This block is used repeatedly to construct an RST block in which even wiring among blocks included in wire shifters is designed as recurring units. By using recurring wire shifters, the authors can expand the level of repeated blocks to cover the entire adder tree, which simplifies the complicated Wallace tree wiring scheme. In addition, to design time savings, layout density is increased by 70% to 6400 transistors/mm², and the multiplication time is decreased by 30% to 13 ns     

Photoluminescence characteristics and pit formation of InGaN/GaN quantum-well structures grown on sapphire substrates by low-pressure metalorganic vapor phase epitaxy

We have examined how a growth interruption, caused by closing group-III sources, affects the crystalline quality of InGaN/GaN quantum-well (QW) structures grown by metalorganic vapor phase epitaxy. The QW samples were characterized by their photoluminescence (PL), and by atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy dispersive x-ray (EDX) microanalysis. The PL peak wavelength was strongly dependent on the duration of the growth interruption and on the number of QW layers. AFM measurements revealed that the size of the open hexagonally shaped pits in the QW structures increased dramatically as the interruption duration was lengthened. Through TEM and EDX microanalysis, we found that the formation of these hexahedronal pits, formed due to the growth interruption, causes a large fluctuation in the In composition, especially around the pits, and the presence of such pits in an underlying QW layer strongly affects the In incorporation into the upper QW layers, leading to significant growth-rate variation in an InGaN QW layer and red-shifting of the PL spectra when a multiple-QW structure is grown.     

Quantum flux parametron: a single quantum flux device for Josephsonsupercomputer

A quantum flux parametron (QFP), a single quantum flux superconductive device that has a potential of up to 100-GHz switching with nW-order power dissipation, is considered. The potential of the QFP and key technologies when QFPs are applied to a Josephson supercomputer are described. Switching speed, stability, and power dissipation of a QFP are discussed. QFP gates, circuits, and systems are next described. Then, ultra-fast clock distribution using a standing wave is explained. High-speed operation at more than 10 GHz and 10¹⁴ error-free operations per QFP have been demonstrated. Finally described is a high-density packaging scheme by three-dimensional integration, which is very important for ultra-high speed circuits because the propagation delay becomes dominant in such circuits     

Gate length scalability of n-MOSFETs down to 30 nm: Comparisonbetween LDD and non-LDD structures

Gate length scalability of LDD and non-LDD n-MOSFETs are investigated in terms of resistance to short-channel effects. Extremely small gate electrodes are delineated using electron beam direct writing and highly selective dry-etching techniques. An LDD MOSFET with As-implanted 15-nm-deep junctions shows a superior scalability down to 30 nm. In contrast, in the case of a non-LDD MOSFET having Sb-δ-doped 18-nm-deep junctions, the drain induced barrier lowering (DIBL) mechanism limits the minimum gate length to around 80 nm, at which favorable device operation is achieved. The difference between built in potential of source/drain junctions (around 0.1 eV) of LDD and non-LDD devices is found to remarkably affect short channel characteristics in the sub-0.1-μm region     

Initiation and propagation of fretting fatigue cracks

Fretting fatigue tests of a carbon steel were carried out. Fatigue cracks were measured by means of electrical resistance and observed with a scanning electron microscope. The mechanism of fretting fatigue failure is discussed from the experimental results. Small fatigue cracks are initiated early in life and some grow to be propagating cracks. Cracks grow to a given depth by tangential stress combined with repeated stress and then propagate with repeated stress alone, causing a knee point in the propagation curve. Fretting fatigue damage is saturated in the first 20–25 % of life which coincides with the knee point. The condition of non-propagating cracks is also known.     

Multidimensional feedforward compensator for industrial systems through pole assignment regulator and observer

A feedforward-compensator-design technique is presented for industrial control systems. The proposed feedforward compensator can improve dynamic characteristics of multidimensional systems by modifying the input signals. The multidimensional feedforward-compensator design is based on the pole assignment regulator, the minimal-order observer, and the conversion from a closed-loop system to an open-loop system. The effectiveness of the proposed feedforward compensator is demonstrated by a simulation study of temperature control of a thermal power plant and by experiments of the contour control of an articulated robot arm.     

Electronically controlled high-speed wavelength-tunable femtosecondsoliton pulse generation using acoustooptic modulator

The compact system of electronically controlled high-speed wavelength-tunable femtosecond (fs) soliton pulse generation is realized for the first time using a passively mode-locked fs fiber laser, a polarization maintaining optical fiber, and an acoustooptic (A-O) modulator. The wavelength of the output pulses can be continuously tuned simply by controlling the input voltage into the A-O modulator. The wavelength of the soliton pulses can be changed at 2.5-μs intervals. Wavelength stabilization, time division wavelength multiplexed soliton pulse generation, and a wavelength scanner have been demonstrated     

Dynamic nuclear self-polarization of Ⅲ-Ⅴ semiconductors

Ⅲ-Ⅴ semiconductors exhibit dynamic nuclear self-polarization (DYNASP) owing to the contact hyperfine interaction (HFI) between optically excited conduction electrons and lattice nuclei.In the self-polarization process at a low temperature,electron spin state and the nuclear polarization (magnetization) exchange a positive feedback,increasing energy splitting of the conduction electron states,thereby a large nuclear polarization.This phenomenon was theoretically predicted previously for conduction electrons excited linearly and elliptically polarized light.The polarization of the conduction electrons was represented by a parameter α in a formula for nuclear polarization (Eq.(9) in Ref.[1]);however,the effect of external magnetic fields on the nuclear polarization was not considered.Therefore,this study introduces this effect by further extending the previous studies.Herein,α'represents the combination of the effects of elliptically polarized electrons and an external magnetic field,which is used in the equations presented in previous studies.When α'=0,a large nuclear polarization is obtained below critical temperature Tc,but no polarization occurs above Tc.When α'＞ 0,the nuclear polarization is enhanced above Tc.Below Tc,the nuclear polarization follows a hysteresis curve when α'is partially manipulated by adjusting the degree of the polarization of the exciting laser.     

A new wastewater treatment technology for mixed acid drainagecontaining fluorine

A new environment-friendly wastewater treatment technology was developed for the treatment of mixed acid drainage containing fluorine. The ordinary wastewater system using “slaked lime” is ineffective at removing fluorine; besides, it cannot decompose “hard-type surfactants” in the wastewater, so the amount of generated sludge and the quality of treated wastewater are not at the satisfactory level. This newly developed wastewater system uses microorganisms and calcium carbonate to treat the industrial wastewater that contains strong chemicals such as acids, bases, and hydrogen peroxide. By changing the structure and construction of the treatment tanks, it is possible to treat calcium carbonate and microorganisms at the same time and decompose hard-type surfactants. This greatly contributes to improved water quality, saves resources, and reduces greenhouse gas emissions to one third those of the old system