Serban Meza

New modified saleh models for memoryless nonlinear power amplifier behavioural modelling

A new generic modified Saleh (MS) model for use in memoryless nonlinear power amplifier (PA) behavioural modelling is proposed. The model was evolved primarily to overcome some particular weaknesses in the original Saleh model when handling the polar AM-PM envelope modelling. From it new two parameter MS polar models are derived. By modelling a near memoryless LDMOS PA amplifying a WCDMA signal, evidence of the improvement in modelling accuracy and performance of the MS over the original Saleh for both polar and quadrature models is provided.

Some new memoryless behavioural models of wireless transmitter solid state power amplifiers

This paper briefly review aspects of memoryless nonlinear power amplifier behavioural models in the context of the more popular ones - the complex power series expansion, the Saleh model, and the Bessel-Fourier (B-F) model. Other models considered are the Fourier model, the Hetrakul & Taylor model and the Berman & Mahle model. Static envelope characteristics, i.e., static AM-AM and/or AM-PM characteristics, are taken as the basis for defining a behavioural model as memoryless. Some new insights and new developments are presented including a new modified Saleh model - evolved to overcome some particular weaknesses of the Saleh model - and considerations on applying the B-F model and its linkage to the Fourier model. Some comparative considerations among models was presented, through their application to modelling an LDMOS amplifier amplifying a WCDMA signal.

Interactive Kanban — Blending Digital and Physical Resources for Collaborative Project Based Learning

Using team projects for teaching agile product development processes requires regular task status reports, following evaluation and further planning. In such scenarios, task boards (like Kanban) provide the most efficient means of centralized team tracking with frequent task status updates. Regular task boards are physical equipment (i.e. whiteboards) having the working area divided in task status zones (i.e. to do, done, in progress), while tasks are noted down on cardboards and then pined to the board. The current paper proposes an improvement in the process of teaching and tracking product development processes classes by implementing a computer-aided task board with real time tracking features. Tickets are defined and created online, then printed and pinned to the physical task board and tracked by a camera. Processing is applied to detect any changes in board status, with real-time update online. The advantages of the proposed blended solution are discussed.

A compact robotic head for automatic acquisition of indoor panoramic images

Indoor exploration based on panoramic images has been of interest in both navigation and visualization scenarios of mobile intelligent systems, becoming an appealing research topic in hardware design and computational algorithms. A detailed profile of an indoor scene further used for 3D reconstruction purposes or visualization requires an accurate high-resolution rendering from multiple camera shots. In panoramic imaging, 360 degree Gigapixel panoramas involve a process of capturing multiple segments at a predefined step according to the physical and optical characteristics of the camera (focal length, field of view, angle of view). Manual shooting in such scenes becomes cumbersome, as high precision and stability is required for prolonged time. The current work, proposes a hardware implementation and software control of a panoramic robotized head (GoSphere), used to automatically capture panoramic segments, that further are to be stitched into panoramic renderings. The proposed model features a light-weight portable design for action cameras, allowing a two axes control for a 360 × 180 degree coverage of the scene. Experimental validation has been made in comparison with a standard panoramic capturing assembly. Limitations and improvement proposals are presented for further development and extensions.

Blended Assessment Concepts for Formal and Informal Engineering Education

Multiple assessment options have been adopted in engineering education in the last years due to different reasons. Most of them are related to increasing the efficiency of the evaluation process applied in each activity performed by students/trainees and decreasing stress among them. The assessment methodology implemented in the formal and informal education programs mentioned in the article includes the automated evaluation approach consisting of assessment of conceptual/theoretical knowledge, as well as competences achieved within individual and/or team projects, hands-on laboratory, or simulation work. An analysis of the assessment scores reveals that end-of-programs assessments looks better if continuous evaluation methods are applied during the whole study act while students and trainees develop their own modes of learning and working based on the assessment results.

The SWARA speech corpus: A large parallel Romanian read speech dataset

This paper introduces one of the largest Romanian speech datasets freely available for both academic and commercial use. The dataset comprises speech data recorded over the last year from 12 speakers, along with 5 other speakers previously recorded in a separate environment. The data was manually segmented at utterance-level and semi-automatically labelled at phone-level. The resulting corpus amounts to approximately 21 hours of high-quality read speech data, split into over 19,000 utterances. The speakers read between 921 and 1493 utterances each. 880 utterances are common to all speakers and add up to over 16 hours of parallel data. We present the steps of performing the recordings and data segmentation, as well as a first use of this corpus in the context of synthetic voice development.

A fuzzy logic approach for the fast approximate computation of image transforms from block JPEG DCT coefficients

Computationally efficient implementation of different image processing and analysis algorithms is crucial in many modern real world applications. Several modern visual analytics applications involve processing large amounts of compressed image/video data on restricted hardware resources, in a numerically efficient manner. In this context, the formulation of some image analysis/processing algorithms in the compressed image/video domain can bring significant benefits in the computational complexity reduction. An important step to image analysis, feature extraction, based on unitary image transforms is addressed in this paper, in a general form. Starting from the fact that in most popular video compression the intraframes are block discrete cosine transform (DCT) encoded, we present and propose a solution to computing any unitary image transform at pixels block level, starting from the DCT coefficients of the block. Since approximate forms of the transforms are often satisfactory, we propose a fuzzy logic system based approach to optimize the computational complexity with minimal loss of image information. The method is exemplified for the case of the Walsh transform, which shows that even the fastest implementation provides (by reconstruction) images of good quality.

Heuristic optimization for the resource constrained Project Scheduling Problem: A systematic mapping

Context: Heuristic optimization has been of strong focus in the recent modeling of the Resource Constrained Project Scheduling Problem (RCPSP), but lack of evidence exists in systematic assessments. New solution methods arise from random evaluation of existing studies. Objective: The current work conducts a secondary study, aiming to systemize existing primary studies in heuristic optimization techniques applied to solving classes of RCPSPs. Method: The systemizing framework consists of performing a systematic mapping study (SM), following a 3-steped protocol. Results: 371 primary studies have been depicted from the multi-stage search and filtering process, to which inclusion and exclusion criteria have been applied. Results have been visually mapped in several distributions. Conclusions: Specific RCPSP classes have been grounded and therefore a rigorous classification is required before performing a systematic mapping. Focusing on recent developments of the RCPSP (2010-2015, a strong interest has been acknowledged on solution methods incorporating AI techniques in meta- and hyper-heuristic algorithms.

Information, information quantum, knowledge

Knowledge is a primary measure that opposes the uncertainty of the existence of a system and that leads, through minimization to the structuring of the system. Knowledge is a discrete, negative measure, made of knowledge quanta. The structuring of the system is done by minimizing the knowledge obtained by information absorption. Information is a kinetic phenomenon of transmission from a source to a user/receiver of the quantity of knowledge within the time quantum, through a communication channel. Information is discrete, negative and is transmitted through information quanta. The information quantum structures dynamic processes.