José Cruz Núñez Pérez

What happens to the traditional taxonomy when a well-known tropical saturniid moth fauna is DNA barcoded?

Abstract. Biodiversity of tropical Saturniidae, as measured through traditionally described and catalogued species, strongly risks pooling cryptic species under one name. We examined the DNA barcodes, morphology, habitus and ecology of 32 ‘well known’ species of dry forest saturniid moths from Area de Conservacion Guanacaste (ACG) in north-western Costa Rica and found that they contain as many as 49 biological entities that are probably separate species. The most prominent splitting of traditional species – Eacles imperialis, Automeris zugana, Automeris tridens, Othorene verana, Hylesia dalina, Dirphia avia, Syssphinx molina, Syssphinx colla, and Syssphinx quadrilineata – is where one species was believed to breed in dry forest and rain forest, but is found to be two biological entities variously distinguishable by DNA barcodes and morphology, habitus, and/or microecological distribution. This implies that ‘standard’ biological information about each traditional species may be an unconscious mix of interspecific information, and begs renewed DNA barcoding, closer attention to so-called intraspecific variation, and increased museum collection and curation of specimens from more individual and ecologically characterised sites – as well as eventually more species descriptions. Simultaneously, this inclusion of sibling species as individual entities in biodiversity studies, rather than pooled under one traditional name, reduces the degree of ecological and evolutionary generalisation perceived by the observer.

Using Automatic Dependent Surveillance-Broadcast Data for Monitoring Aircraft Altimetry System Error

*† ‡ Altimetry System Error (ASE) is a measure of the height-keeping performance of an aircraft. In airspace where the Reduced Vertical Separation Minimum (RVSM) is applied, the importance of accurate aircraft height-keeping is magnified. ASE is not detectible in routine operations; specialized measurement equipment is necessary to independently measure the errors. To be eligible for RVSM operations, operators must adhere to the height-keeping performance monitoring requirements established for the airspace in which operations are to be conducted. The Federal Aviation Administration (FAA) developed a process to monitor the height-keeping performance of aircraft for RVSM operations. The International Civil Aviation Organization (ICAO) has established long-term minimum monitoring requirements to be used by the regions where the RVSM is implemented which go into effect in November 2010. This paper progresses the work which considers the role of a Next Generation Air Transportation System (NextGen) technology, Automatic Dependent Surveillance–Broadcast (ADS-B), to monitor the height-keeping performance of aircraft. This paper contains results from test flights conducted at the FAA Technical Center to compare aircraft geometric height obtained from three sources; ADS-B, EGMU, and an onboard independent GPS reference receiver. In addition, this paper presents initial results from ADS-B data collected from real airspace operations. The ADS-B data made available for this work result from a cooperative research agreement between the FAA and Airservices Australia The results of this study will be used to determine the quality control processes needed for monitoring aircraft ASE using ADS-B geometric height data.

Asymmetrically-driven current-based chireix class-F power amplifier designed using an embedding device model

Model-based nonlinear embedding is applied for the first time to the design of an asymmetrically-driven class-F Chireix power amplifier (PA). The embedding model of a 15 W GaN HEMT is used to determine the optimum load impedances for the fundamental and multi-harmonics required at the package reference planes such that the two intrinsic transistors operate with a recently reported ideal current-based Chireix combiner. A symmetric circuit topology is used so that the phase offset of the Chireix combiner is maintained through the design from the intrinsic and packaged nodes up to the drive generators. Unlike the conventional Chireix PA, which is driven with constant envelope signals, this PA designed using embedding is found to require asymmetrical amplitude and phase modulated input drives to support the targeted equal-power input signals at the intrinsic reference planes. The Chireix PA designed exhibits a peak drain efficiency of 79.6 % and power added-efficiency (PAE) over 77/71% around peak power (43/44 dBm) and 55% at 8dB backoff power (36dBm) at 2 GHz as measured with a large-signal network analyzer (LSNA). Using a lookup table driver, the PA average drain efficiency is 50% for a 5 MHz W-CDMA signal with 9.3 dB PAPR and −41.5 dBc ACPR achieved.

A Reconfigurable Buck, Boost, and Buck-Boost Converter: Unified Model and Robust Controller

The need for reconfigurable, high power density, and low-cost configurations of DC-DC power electronic converters (PEC) in areas such as the transport electrification and the use of renewable energy has spread out the requirement to incorporate in a single circuit several topologies, which generally result in an increment of complexity about the modeling, control, and stability analyses. In this paper, a reconfigurable topology is presented which can be applied in alterative/changing power conversion scenarios and consists of a reconfigurable Buck, Boost, and Buck-Boost DC-DC converter (RBBC). A unified averaged model of the RBBC is obtained, a robust controller is designed through a polytopic representation, and a Lyapunov based switched stability analysis of the closed-loop system is presented. The reported RBBC provides a wide range of voltage operation, theoretically from to volts with a single power source. Robust stability, even under arbitrarily fast (bounded) parameter variations and reconfiguration changes, is reported including numerical and experimental results. The main advantages of the converter and the robust controller proposed are simple design, robustness against abrupt changes in the parameters, and low cost.

Local Search Approach to Genetic Programming for RF-PAs Modeling Implemented in FPGA

This paper presents a genetic programming (GP) approach enhanced with a local search heuristic (GP-LS) to emulate the Doherty 7 W @ 2.11 GHz Radio Frequency (RF) Power Amplifier (PA) conversion curves. GP has been shown to be a powerful modeling tool, but can be compromised by slow convergence and computational cost. The proposal is to combine the explorative search of standard GP, which build the syntax of the solution, with numerical methods that perform an exploitative and greedy local optimization of the evolved structures. The results are compared with traditional modeling techniques, particularly the memory polynomial model (MPM). The main contribution of the paper is the design, comparison and hardware emulation of GP-LS for FPGA real applications. The experimental results show that GP-LS can outperform standard MPM, and suggest a promising new direction of future work on digital pre-distortion (DPD) that requires complex behavioral models.

Design and Optimization of 20 GHz LC-VCOs in SiGe:C BiCMOS Technology

The design and analysis of fully integrated voltage controlled oscillators (VCO) for 20 GHz low cost and low power communication system is presented in this paper. Two differential topologies have been studied: balanced Colpitts VCO and LC-VCO using a cross-coupled differential pair. We have focussed on oscillation frequency, tuning range, phase noise, and output power optimization and buffer stage specifications. SiGe:C hetero-junction bipolar transistors of fT=55 GHz have been used and produced with a monolithic BiCMOS technology.

Experimental B-learning laboratory for an electrical machines undergraduate course

This paper presents the development of an experimental B-learning laboratory for an electrical machines undergraduate course. A custom conditioning signal board was developed from scratch that fits a low-cost data acquisition board used to interact with the LabVIEW real time target. In addition a friendly graphical user interface was developed that allows real time remote user interaction. The system was developed and fully tested in a standard Lucas-Nulle 300W electrical machines module. It is shown that the resulting system can be extended to other modules already in the market, and the conditioning signal board adapted to other electrical engineering courses.

Global system approach to validate a wireless system even with a multi-antennas receiver structure

This article discusses key points to easily develop, simulate and validate a large scale platform to evaluate different possible combinations of promising techniques in the field of converged wireless systems. The idea is there to propose to merge a maximum of degrees of freedom to offer an agile enough receiver, by the addition of multi-antenna, multi-standard and multichannel principles. A general architecture is presented and major relevant points are described.

Analysis and design of 20 GHz VCOs using cross-coupled differential pair and balanced Colpitts topologies in SiGe:C BiCMOS technology

The design and analysis of fully integrated voltage controlled oscillators (VCO) for 20 GHz low cost and low power communication system is presented in this paper. Two differential topologies have been studied: balanced Colpitts VCO and LC-VCO using a cross-coupled differential pair. We have focussed on oscillation frequency, tuning range, phase noise, and output power optimization and buffer stage specifications. SiGe:C hetero-junction bipolar transistors of fT=55 GHz have been used and produced with a monolithic BiCMOS technology.