A current-mode bit-block circuit applicable to low-voltage, low-power pipeline video-speed A/D converters

This paper describes a study to determine if a current-mode circuit is useful as an analog circuit technique for realizing submicron mixed analog-and-digital MOS LSIs. To examine this, we designed and circuit simulated a new current-mode ADC bit-block for a 3 V, 10-bit level, 20 MHz ADC with a pipeline architecture and with full current-mode approach. A new precision current-mode sample-and-hold circuit which enables operation of a bit block at a clock speed of 20 MHz was developed. Current mismatches caused by the poor output impedance of a device were also decreased by adopting a cascode configuration throughout the design. Operation with a 3 V power supply and a 20 MHz clock speed in a 3-bit A/D configuration was verified through circuit simulation using standard CMOS 0.6 m device parameters. Gain error, mismatch of current, and linearity of the bit block with changing threshold voltage of a device were carefully examined. The bit block has a gain error of 0.2% (10-bit level), a linearity error of less than 0.1% (more than 10-bit level), and a current mismatch of DAC current sources in a bit cell of 0.2 to 0.4% (more than 8-bit level) with a 3 V power supply and 20 MHz clock speed. An 8-to 9-bit video-speed pipeline ADC can be realized without calibration. This confirms that the current-mode approach is effective.     

The robustness of a Nash equilibrium simulation model: Game-theoretic approach using variable metric projection method

This paper proposes a Nash equilibrium model that applies continuous time replicator dynamics to the analysis of oligopoly markets. The robustness of the proposed simple Nash equilibrium model under the simultaneous constraints of allocation of product and market share using a simulation method to derive an optimal solution for production decisions by rival firms in oligopoly markets is tested by changing profit and cost function parameters, as well as the initial production values and market shares of the firms examined in this study. The effects of differences in conjectural variation and initial allocation of market share on the convergent values are considered, particularly in the case of corner solutions. This approach facilitates the understanding of the robustness of attaining equilibrium in an oligopoly market.     

Short‐term load forecasting using informative vector machine

In this paper, a novel method is proposed for short‐term load forecasting, which is one of the important tasks in power system operation and planning. The load behavior is so complicated that it is hard to predict the load. The deregulated power market is faced with the new problem of an increase in the degree of uncertainty. Thus, power system operators are concerned with the significant level of load forecasting. Namely, probabilistic load forecasting is required to smooth power system operation and planning. In this paper, an IVM (Informative Vector Machine) based method is proposed for short‐term load forecasting. IVM is one of the kernel machine techniques that are derived from an SVM (Support Vector Machine). The Gaussian process (GP) satisfies the requirements that the prediction results are expressed as a distribution rather than as points. However, it is inclined to be overtrained for noise due to the basis function with N² elements for N data. To overcome this problem, this paper makes use of IVM that selects necessary data for the model approximation with a posteriori distribution of entropy. That has a useful function to suppress the excess training. The proposed method is tested using real data for short‐term load forecasting. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(2): 23– 31, 2009; Published online in Wiley InterScience ( www. interscience.wiley.com ). DOI 10.1002/eej.20693     

Improvement of gas barrier property of polyolefins by diamond‐like carbon deposition and photografting polymerization

The gas barrier properties of isotactic polypropylene (iPP) and high‐density polyethylene (HDPE) are both significantly improved by diamond‐like carbon (DLC) deposition and photografting polymerization using acrylic acid (AA) monomers. In fact, the gas barrier properties can be highly improved just by DLC or by AA‐photografting polymerization. The improvement observed by AA‐photografting polymerization is more pronounced than that by DLC deposition in our general experimental condition. In more detail, the oxygen barrier property of DLC‐deposited and AA‐grafted iPP is considerably improved by ～10 times when compared with that of neat iPP. As for HDPE, the oxygen barrier property is enhanced by nearly six times through DLC deposition and photografting polymerization. By observing the surfaces, 30 nm layer of DLC and 1.0 μm of AA‐grafted layer are firmly constructed on the polyolefins, which should contribute to the enhancement of the oxygen barrier property. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Global optimization with the PSO coupling‐type discrete gradient chaos model

In this paper, we propose a new multiagent discrete gradient chaos model using a coupling structure which PSO has. Concretely, first, we introduce a multiagent‐type optimization model whose agents search autonomously with the discrete gradient chaos model which is the simplest dynamical global search model, and they are coupled by convective coupling. Convective coupling in this model is used to aim at overcoming of emergence of boundary crisis which is a problem of the original discrete gradient chaos model. Second, we introduce PSO coupling structure, where population drifts to the “gbest” and the “pbest”, into discrete gradient chaos model. Then, we propose “PSO coupling‐type discrete gradient chaos model” with the search strategy based on objective function's value. In this paper, our proposed models are applied to several benchmark problems. The results show that our proposed models have better global optimization ability than the original discrete gradient chaos model and PSO model. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 67–75, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20563     

The impact of comparison processes on coactors' task performance.

Conducted 2 experiments with 135 female undergraduates to investigate the operation of social comparison processes within coaction. Perceived discrepancies between coactors' performance levels were induced by altering their feedback schedules. An S was paired with a coactor who seemed to be performing either at a superior, inferior, or similar level. The pattern of results suggests that comparison processes are active components within coaction. An expectation/criterion level interpretation is discussed within a social comparison analysis. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrode biomaterials based on immobilized laccase. Application for enzymatic reduction of dioxygen

Three different methods of immobilization of the laccase enzyme have been studied by measuring the enzyme activity of the bioelectrode and its catalytic efficiency for dioxygen reduction in the presence of the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) as a redox mediator. One approach has consisted in laccase entrapment in polypyrrole matrix electrogenerated on the electrode surface. The two other approaches have concerned the grafting of laccase on an original aminopolypyrrole film and the complexation of laccase with avidin and biotin reagents. The laccase activity and the catalytic current of dioxygen reduction have demonstrated the efficiency of covalent grafting to aminopolypyrrole film. The polymer thickness was a key parameter of the catalytic efficiency and stability of this type of biocathode.