874 resultados para learning and digital media
Resumo:
This paper proposes two kinds of novel single-electron analog-digital conversion (ADC) and digital-analog conversion (DAC) circuits that consist of single-electron transistors (SETs) and metal-oxide-semiconductor (MOS) transistors. The SET/MOS hybrid ADC and DAC circuits possess the merits of the SET circuit and the MOS circuit. We obtain the SPICE macro-modeling code of the SET transistor by studying and fitting the characteristics of the SET with SPICE simulation and Monte Carlo simulation methods. The SPICE macro-modeling code is used for the simulation of the SET/MOS hybrid ADC and DAC circuits. We simulate the performances of the SET/MOS hybrid 3-b ADC and 2-b DAC circuits by using the H-SPICE simulator. The simulation results demonstrate that the hybrid circuits can perform analog-digital and digital-analog data conversion well at room temperature. The hybrid ADC and DAC circuits have advantages as-follows: 1) compared with conventional circuits, the architectures of the circuits are simpler; 2) compared with single electron transistor circuits, the circuits have much larger load capability; 3) the power dissipation of the circuits are lower than uW; 4) the data conversion rate of the circuits can exceed 100 MHz; and 5) the resolution of the ADC and DAC circuits can be increased by the pipeline architectures.
Resumo:
An air- and water-stable PEG-supported bidentate nitrogen ligand is prepared and its applications in the palladium-catalyzed Suzuki reaction of aryl halides with arylboronic acids in PEG and Suzuki-type reaction of aryl halides with sodium tetraphenylborate in aqueous media are reported. The homogeneous catalyst system is environmentally friendly and offers the advantages of high activity, reusability and easy separation.
Resumo:
Heteropoly acids (HPAs), such as dodecatungstosilicic acid (SiW12), adsorb strongly on to activated carbons. The surface chemical properties of the activated carbons have a pronounced effect on the adsorption of HPAs. To obtain activated carbons with the desired surface chemical properties, modification with mineral acids has been applied. The adsorption isotherms of SiW12 from aqueous solution and various acidic media on to the various carbons have been studied. On the basis of the results obtained, an adsorption model for HPAs from acidic media is presented.
Resumo:
In various acidic media, such as H2SO4, HCl, H3PO4, acetic acid of 3 M in hydrogen ion concentration, and pure acetic acid, the adsorption of heteropolyacids composed of molybdenum with the Keggin structures PMo12 and SiMo12 on different activated carbons is studied. In acidic media, the adsorbed amount of heteropolyacids is much higher than that in water. By considering the relation between adsorbed amount and the acid strength of the media, as far as SiMo12 and PMo12 are concerned, there exist different trends.
Resumo:
In a Communication Bootstrapping system, peer components with different perceptual worlds invent symbols and syntax based on correlations between their percepts. I propose that Communication Bootstrapping can also be used to acquire functional definitions of words and causal reasoning knowledge. I illustrate this point with several examples, then sketch the architecture of a system in progress which attempts to execute this task.
Resumo:
This thesis presents a learning based approach for detecting classes of objects and patterns with variable image appearance but highly predictable image boundaries. It consists of two parts. In part one, we introduce our object and pattern detection approach using a concrete human face detection example. The approach first builds a distribution-based model of the target pattern class in an appropriate feature space to describe the target's variable image appearance. It then learns from examples a similarity measure for matching new patterns against the distribution-based target model. The approach makes few assumptions about the target pattern class and should therefore be fairly general, as long as the target class has predictable image boundaries. Because our object and pattern detection approach is very much learning-based, how well a system eventually performs depends heavily on the quality of training examples it receives. The second part of this thesis looks at how one can select high quality examples for function approximation learning tasks. We propose an {em active learning} formulation for function approximation, and show for three specific approximation function classes, that the active example selection strategy learns its target with fewer data samples than random sampling. We then simplify the original active learning formulation, and show how it leads to a tractable example selection paradigm, suitable for use in many object and pattern detection problems.
Resumo:
This thesis examines a complete design framework for a real-time, autonomous system with specialized VLSI hardware for computing 3-D camera motion. In the proposed architecture, the first step is to determine point correspondences between two images. Two processors, a CCD array edge detector and a mixed analog/digital binary block correlator, are proposed for this task. The report is divided into three parts. Part I covers the algorithmic analysis; part II describes the design and test of a 32$\time $32 CCD edge detector fabricated through MOSIS; and part III compares the design of the mixed analog/digital correlator to a fully digital implementation.
Resumo:
Training that is relevant to employers is not necessarily enriching for employees, especially those on the lower salary scales. The authors argue that the analysis of training and development needs to be understood in the context of the employment relationship. Drawing on reasearch evidence from six case studies in the public sector, the article examines the impact of changes in work organisation on workplace learning, managers' and employees' own strategies towards it and the limitations of tools such as appraisal. Since employees' existing qualifications are poorly utilised and their development needs often frustrated, issues concerning job design, occupational progression routes and employee entitlements need to be addressed