Low frequency noise and technology induced mechanical stress in MOSFETs

A detailed experimental investigation of low frequency noise as a function of technology-induced mechanical stress in MOSFET devices is presented. Both n- and p-MOSFETs have been studied. Strain in the channel region is obtained by the Shallow Trench Isolation (STI) technique. An increasing of 1/f noise intensity when compressive mechanical stress increases has been detected in p-channel transistor. A critical discussion of this experimental finding has been proposed in the scenario of advanced generation CMOS technologies.     

Textureless macula swelling detection with multiple retinal fundus images

Retinal fundus images acquired with nonmydriatic digital fundus cameras are versatile tools for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or point-of-care (PoC) applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyze the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image, which are useful in PoC automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalizes the image; second, all available views are registered using nonmorphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naive height map of the macula. Results are presented on three sets of synthetic images and two sets of real-world images. These preliminary tests show the ability to infer a minimum swelling of 300 μm and to correlate the reconstruction with the swollen location.     

Frequency-related effects in the optimization of coils for the magnetic stimulation of the nervous system

Magnetic stimulation of the nervous system is a non-invasive technique with a large number of applications in neurological diagnosis, brain research, and, recently, therapy. New applications require engineering modifications in order to decrease power consumption and coil heating. This can be accomplished by optimized coils with minimized resistance. In this study the influence of some frequency-related effects (skin and proximity effect) on the coil resistance will be discussed, together with the role played by wire shape, wire section, and twisting effect. The results show that the coil resistance increases with frequency. As an example, for a 20-mm2 circular wire section, the skin effect in the typical frequency range of magnetic stimulator devices (2-4 kHz) increases the coil resistance up to about 45% with respect to its dc value. Moreover, the influence of the frequency is lower for flat wire sections and reasonably small helix twist angle of the coil.     

Degradation mechanisms in polysilicon emitter bipolar junction transistors for digital applications

This paper is a thorough overview on polysilicon bipolar junction transistors’ (BJTs) reliability, with focus on transistors for digital applications, where the base–emitter junction switches from forward to reverse bias (low fields) and the base–collector junction is reverse biased at high fields. The effects of base–emitter reverse biasing are generation, charging and discharging of traps in silicon oxide or at the Si–SiO₂ interface near the base–emitter junction; their understanding is essential to model transistor current gain degradation and low frequency noise increase. Failure modes and mechanisms, degradation kinetics, lifetime models and physical phenomena related to device aging will be discussed. The base–emitter junction is also stressed by high currents, which lead, for example, to electromigration phenomena. The base–collector junction degradation is mainly due to high field and impact-ionization effects. Reliability constraints are now an important component of a correct design methodology in deep-sub-micron integrated circuits.     

New developments of THERMOS, a tool for 3D electro-thermal simulation of smart power MOSFETs

In this work, we present a novel 3D electro-thermal simulation tool capable of taking into account also particular driving strategies of the electron device, as it may be the case of smart power MOSFETs where a control logic interacts with the power section and controls its dissipated power and temperature. As an example, a thermal shutdown circuit, capable of reading the temperature on chip and switching the device off if the latter reaches dangerous values, usually embedded within smart power devices used in automotive applications to drive direction light or small motors/actuators, is simulated to validate our approach.     

Automated Design Flow for Multi-Functional Dataflow-Based Platforms

The implementation of processing platforms supporting multiple applications by runtime reconfigurations on dedicated hardware modules requires the solution of different problems. These problems are notably not-trivial since both platform and application complexities increase year after year. As a consequence, the design process is both time and resource demanding. System configuration along with resources management and mapping remain one of the most challenging problem, particularly when runtime adaptation is required. In this direction, the ISO/IEC SC29WG11 committee (MPEG) has developed the so called MPEG-RVC standards ISO/IEC 23001-4 and 23002-4. This standard provides specifications of video codecs in the form of dataflow programs. In this paper, an integrated design flow to derive optimized multi-functional platforms directly from disjoined high-level specifications is presented. To the authors’ best of knowledge, such an optimization, synthesis and mapping methodology for coarse-grained reconfigurable systems design does not exist within the MPEG-RVC framework. The design flow presented in this paper leverages on an integrated set of independently designed tools, all supporting the RVC standard. Results assessment has been carried out on three different scenarios: an MPEG-RVC decoder, a standard baseline MPEG-RVC JPEG codec and a generalized reconfigurable multi-quality JPEG encoder. For all these scenarios, the proposed design flow has been targeted for a Xilinx Virtex 5 FPGA. Results show how this approach is capable of yielding a reconfigurable design that preserves the original performance of the stand alone non-reconfigurable platform providing, at the same time, considerable area savings featuring a larger set of functionalities. Moreover, platforms programmability, on the basis of the required functionality ID, is automatically handled at runtime without any designer effort.     

An OpenCL-based feature matcher

Nowadays visual search is one of the most active branches of computer vision. It relies on finding invariant points inside images, describing them into features and then matching these features against a reference database to identify objects in the scene or the entire photo (environment). In this paper, we discuss an approach to feature matching that exploits the capabilities of modern GPUs to speed up the aforementioned and that keeps low the number of false matches.     

Implementation of a Moving Target Tracking Algorithm Using Eye-RIS Vision System on a Mobile Robot

A moving target tracking algorithm is proposed here and implemented on the Anafocus Eye-RIS vision system, which is a compact and modular platform to develop real time image processing applications. The algorithm combines moving-object detection with feature extraction in order to identify the specific target in the environment. The algorithm was tested in a mobile robotics experiment in which a robot, with the Eye-RIS mounted on it, pursued another one representing the moving target, demonstrating its performance and capabilities.     

On the Power Assignment Problem in Radio Networks

Given a finite set S of points (i.e. the stations of a radio network) on a d-dimensional Euclidean space and a positive integer 1h|S|–1, the MIN DD H-RANGE ASSIGNMENT problem consists of assigning transmission ranges to the stations so as to minimize the total power consumption, provided that the transmission ranges of the stations ensure the communication between any pair of stations in at most h hops.Two main issues related to this problem are considered in this paper: the trade-off between the power consumption and the number of hops; the computational complexity of the MIN DD H-RANGE ASSIGNMENT problem.As for the first question, we provide a lower bound on the minimum power consumption of stations on the plane for constant h. The lower bound is a function of |S|, h and the minimum distance over all the pairs of stations in S. Then, we derive a constructive upper bound as a function of |S|, h and the maximum distance over all pairs of stations in S (i.e. the diameter of S). It turns out that when the minimum distance between any two stations is not too small (i.e. well spread instances) the upper bound matches the lower bound. Previous results for this problem were known only for very special 1-dimensional configurations (i.e., when points are arranged on a line at unitary distance) [Kirousis, Kranakis, Krizanc and Pelc, 1997].As for the second question, we observe that the tightness of our upper bound implies that MIN 2D H-RANGE ASSIGNMENT restricted to well spread instances admits a polynomial time approximation algorithm. Then, we also show that the same approximation result can be obtained for random instances. On the other hand, we prove that for h=|S|–1 (i.e. the unbounded case) MIN 2D H-RANGE ASSIGNMENT is NP-hard and MIN 3D H-RANGE ASSIGNMENT is APX-complete.