Low-frequency noise properties of dynamic-threshold (DT) MOSFET's

This paper shows that MOSFET operated in dynamic-threshold (DT) mode (V_body=V_gate) is more suitable for low-noise RF/analog applications than those operated in conventional mode (V_body=V_source). Detailed low-frequency noise properties of these two modes of device operation were compared for 0.31-μm gate MOSFET's, in which NMOS's are surface-channel devices (S.C.) and PMOS's are buried-channel (B.C.) devices. Experimental data show that when the devices are biased at same transconductance, the low-frequency noise in DT mode is 30 times lower (at g_m=2.2×10^-3 S) than that in the conventional mode for the B.C. devices and ten times (at g_m=2.0×10 ^-3 S) lower for the S.C. devices     

Truth and credibility as a double ambition: reconstruction of the built past,experiences and dilemmas

The reconstruction of our historical heritage involves a few fundamental problems. We mention only two. There can be many interpretations of scientific data which can result in different reconstructions: however, the appearance of an image or animation in a digital format out of context is nearly always misleading. Therefore, the verisimilitude of the computer‐based image should be questioned in the same manner as a picture in a journal, but the digital medium seldom facilitates this questioning. Furthermore, the diffusion of visualizations raises concerns; currently there is no established ontology to moderate the process. This article is based on our own experiences and attempts to contribute to this ontology. In this, scientific ‘truth’ will go hand in hand with artistic credibility, which to many may come as a surprise. Copyright © 2003 John Wiley & Sons, Ltd.     

The slippery road to sliding control: conventional versus dynamical sliding mode control

Theory and design of a conventional sliding mode controller (CSMC) and a dynamical sliding mode controller (DSMC) are discussed and compared. The controllers are applicable to uncertain nonlinear MIMO systems. Emphasis is put on handling of unmodelled dynamics, tuning of controller parameters, suppression of chattering, and robust tracking performance. Experiments are performed with a mechanical manipulator. Errors in the model of this manipulator are due to, amongst other things, neglected flexibilities. It is concluded that for this set-up the robustness to these model-reality differences is approximately the same for both controllers, while nominal performance is best for the CSMC. © 1998 John Wiley & Sons, Ltd.     

Linear Diophantine equation (LDE) decoder: A training-free decoding algorithm for multifrequency SSVEP with reduced computation cost

Multifrequency steady-state visual evoked potentials (SSVEPs) have been developed to extend the capability of SSVEP-based brain-machine interfaces (BMIs) to complex applications that have large numbers of targets. Even though various multifrequency stimulation methods have been introduced, the decoding algorithms for multifrequency SSVEP are still in early development. The recently developed multifrequency canonical correlation analysis (MFCCA) was shown to be a feasible training-free option to use in decoding multifrequency SSVEPs. However, the time complexity of MFCCA is shown to be $O(n^3)$, which will lead to long computation time as $n$ grows, where $n$ represents the input size in decoding. In this paper, a novel decoding algorithm is proposed with the aim to reduce the time complexity. This algorithm is based on linear Diophantine equation solvers and has a reduced computation cost $O(nlogn)$ while remaining training-free. Our simulation results demonstrated that linear Diophantine equation (LDE) decoder run time is only one fifth of MFCCA run time under respective optimal settings on 5-s single-channel data. This reduced computation cost makes it easier to implement multifrequency SSVEP in real-time systems. The effectiveness of this new decoding algorithm is validated with nine healthy participants when using dry electrode scalp electroencephalography (EEG).     

Exploring the Potential of Wire Fed Direct Energy Deposition of Aluminum–Boron Nitride Nanotube Composite: Microstructural Evolution and Mechanical Properties

Recent advancements have shown great promise in utilizing wire-fed direct energy deposition (DED) for building aluminum alloy structures. However, utilizing the wire-fed DED approach for fabricating metal matrix composite structures remains a significant challenge. Herein, a wire-based additive manufacturing process is used to successfully produce a 1D boron nitride nanotube (BNNT)-reinforced aluminum composite with high strength. Al-BNNT electrode is developed in house. The microstructural changes that occur during layer-by-layer deposition are investigated. The grain morphology changes from equiaxed grains in the bottom layer to columnar grains in the top layer. BNNTs act as nuclei to promote the formation of equiaxed grains and interfacial compounds (AlN and AlB₂) during solidification. This results in improved strength, with Al-BNNT composite exhibiting a tensile strength of 47 MPa, 2.3 times higher than its pure Al. Higher strength is attributed to the retention and uniform distribution of BNNT reinforcement in the melt pool, leading to effective load transfer. This study demonstrates the potential of additive manufacturing for producing high-performance metal matrix composites with novel 1D reinforcements and improved multifunctional properties.     

Object-based approach to programming distributed systems

Two kinds of parallel computers exist: those with shared memory and those without. The former are difficult to build but easy to program. The latter are easy to build but difficult to program. In this paper we present a hybrid model that combines the best properties of each by simulating a restricted object-based shared memory on machines that do not share physical memory. In this model, objects can be replicated on multiple machines. An operation that does not change an object can then be done locally, without any network traffic. Update operations can be done using the reliable broadcast protocol described in the paper. We have constructed a prototype system, designed and implemented a new programming language for it, and programmed various applications using it. The model, algorithms, language, applications and performance will be discussed.     

Retrieval-based language model adaptation for handwritten Chinese text recognition

International Journal on Document Analysis and Recognition (IJDAR) - In handwritten text recognition, compared to human, computers are far short of linguistic context knowledge, especially...     

Dependability analysis of stand‐alone photovoltaic systems

Long‐term performance of PV stand‐alone systems is analysed in this work in terms of dependability. On one side, the quality of a PV system, the energy service supplied to the users, depends on the initial design and sizing and on the component ageing that progressively decreases the availability of supply on demand (energy reliability). On the other side, technical failures lead to system stoppage until repairing is performed (technical reliability), which is crucial in real rural electrification applications. All those factors are analysed together with the basis of an extended field, laboratory and bibliographic review work. Copyright © 2006 John Wiley & Sons, Ltd.