Showing papers in "Electronics in 2013"

A Simulative Study on Active Disturbance Rejection Control (ADRC) as a Control Tool for Practitioners

Abstract: As an alternative to both classical PID-type and modern model-based approaches to solving control problems, active disturbance rejection control (ADRC) has gained significant traction in recent years. With its simple tuning method and robustness against process parameter variations, it puts itself forward as a valuable addition to the toolbox of control engineering practitioners. This article aims at providing a single-source introduction and reference to linear ADRC with this audience in mind. A simulative study is carried out using generic first- and second-order plants to enable a quick visual assessment of the abilities of ADRC. Finally, a modified form of the discrete-time case is introduced to speed up real-time implementations as necessary in applications with high dynamic requirements.

Fault Tree Analysis for Safety/Security Verification in Aviation Software

Abstract: The Next Generation Air Traffic Management system (NextGen) is a blueprint of the future National Airspace System. Supporting NextGen is a nation-wide Aviation Simulation Network (ASN), which allows integration of a variety of real-time simulations to facilitate development and validation of the NextGen software by simulating a wide range of operational scenarios. The ASN system is an environment, including both simulated and human-in-the-loop real-life components (pilots and air traffic controllers). Real Time Distributed Simulation (RTDS) developed at Embry Riddle Aeronautical University, a suite of applications providing low and medium fidelity en-route simulation capabilities, is one of the simulations contributing to the ASN. To support the interconnectivity with the ASN, we designed and implemented a dedicated gateway acting as an intermediary, providing logic for two-way communication and transfer messages between RTDS and ASN and storage for the exchanged data. It has been necessary to develop and analyze safety/security requirements for the gateway software based on analysis of system assets, hazards, threats and attacks related to ultimate real-life future implementation. Due to the nature of the system, the focus was placed on communication security and the related safety of the impacted aircraft in the simulation scenario. To support development of safety/security requirements, a well-established fault tree analysis technique was used. This fault tree model-based analysis, supported by a commercial tool, was a foundation to propose mitigations assuring the gateway system safety and security.

Graphene and Graphene Nanomesh Spintronics

Abstract: Spintronics, which manipulate spins but not electron charge, are highly valued as energy and thermal dissipationless systems. A variety of materials are challenging the realization of spintronic devices. Among those, graphene, a carbon mono-atomic layer, is very promising for efficient spin manipulation and the creation of a full spectrum of beyond-CMOS spin-based nano-devices. In the present article, the recent advancements in graphene spintronics are reviewed, introducing the observation of spin coherence and the spin Hall effect. Some research has reported the strong spin coherence of graphene. Avoiding undesirable influences from the substrate are crucial. Magnetism and spintronics arising from graphene edges are reviewed based on my previous results. In spite of carbon-based material with only sp2 bonds, the zigzag-type atomic structure of graphene edges theoretically produces spontaneous spin polarization of electrons due to mutual Coulomb interaction of extremely high electron density of states (edge states) localizing at the flat energy band. We fabricate honeycomb-like arrays of low-defect hexagonal nanopores (graphene nanomeshes; GNMs) on graphenes, which produce a large amount of zigzag pore edges, by using a nonlithographic method (nanoporous alumina templates) and critical temperature annealing under high vacuum and hydrogen atmosphere. We observe large-magnitude ferromagnetism, which arises from polarized spins localizing at the hydrogen-terminated zigzag-nanopore edges of the GNMs, even at room temperature. Moreover, spin pumping effects are found for magnetic fields applied in parallel with the few-layer GNM planes. Strong spin coherence and spontaneously polarized edge spins of graphene can be expected to lead to novel spintronics with invisible, flexible, and ultra-light (wearable) features.

Model-driven Techniques for Data Model Synthesis

Abstract: This article presents a survey of model-driven techniquesfor data model synthesis. During an extensive research,we identified more than 70 research papers in the field andmore than 15 different graphical notations used for the sourcemodel representation.We have classified the proposed approachesinto four distinct groups: function-oriented, process-oriented,communication-oriented and goal-oriented. Their contributionsare presented in chronological order and evaluated based onseveral main criteria. Although the idea of model-driven designof the data model is more than 25 years old, the survey showsthe richness and diversity of ideas, but only a small number ofimplemented automatic generators.

Carbon Nanotubes and Graphene Nanoribbons: Potentials for Nanoscale Electrical Interconnects

Abstract: Carbon allotropes have generated much interest among different scientific communities due to their peculiar properties and potential applications in a variety of fields. Carbon nanotubes and more recently graphene have shown very interesting electrical properties along with the possibility of being grown and/or deposited at a desired location. In this Review, we will focus our attention on carbon-based nanostructures (in particular, carbon nanotubes and graphene nanoribbons) which could play an important role in the technological quest to replace copper/low-k for interconnect applications. We will provide the reader with a number of possible architectures, including single-wall as well as multi-wall carbon nanotubes, arranged in horizontal and vertical arrays, regarded as individual objects as well as bundles. Modification of their functional properties in order to fulfill interconnect applications requirements are also presented. Then, in the second part of the Review, recently discovered graphene and in particular graphene and few-graphene layers nanoribbons are introduced. Different architectures involving nanostructured carbon are presented and discussed in light of interconnect application in terms of length, chirality, edge configuration and more.

Morlet Wavelet UDWT Denoising and EMD based Bearing Fault Diagnosis

Abstract: Bearing Faults in rotating machinery occur as low energy impulses in their vibration signal and are lost in the noise. This signal has to be properly denoised before analyzing for effective condition monitoring. This paper proposes a novel method to denoise and analyze such a noisy signal. The Undecimated Discrete Wavelet Transform (UDWT) with Morlet wavelet based De-noising method is used to denoise the signal. Then this denoised signal is decomposed by Empirical Mode Decomposition (EMD) into a number of Intrinsic Mode Functions (IMF). The impulses in the signal, corresponding to the characteristic fault frequency, are seen clearly in the FFT of the IMFs. A Fast Fourier Transform (FFT), Wavelet Transform (WT), Empirical Mode Decomposition and Envelope Detection are also performed with the acquired signal and all the results are compared with the proposed method. These results clearly show the effectiveness of proposed method in detecting the faults.

Current-Perpendicular-to-Plane Magnetoresistance in Chemical Vapor Deposition-Grown Multilayer Graphene

Abstract: Current-perpendicular-to-plane (CPP) magnetoresistance (MR) effects are often exploited in various state-of-the-art magnetic field sensing and data storage technologies. Most of the CPP-MR devices are artificial layered structures of ferromagnets and non-magnets, and in these devices, MR manifests, due to spin-dependent carrier transmission through the constituent layers. In this work, we explore another class of artificial layered structure in which multilayer graphene (MLG) is grown on a metallic substrate by chemical vapor deposition (CVD). We show that depending on the nature of the graphene-metal interaction, these devices can also exhibit large CPP-MR. Magnetoresistance ratios (>100%) are at least two orders of magnitude higher than “transferred” graphene and graphitic samples reported in the literature, for a comparable temperature and magnetic field range. This effect is unrelated to spin injection and transport and is not adequately described by any of the MR mechanisms known to date. The simple fabrication process, large magnitude of the MR and its persistence at room temperature make this system an attractive candidate for magnetic field sensing and data storage applications and, also, underscore the need for further fundamental investigations on graphene-metal interactions.

Variability and Reliability of Single-Walled Carbon Nanotube Field Effect Transistors

Abstract: Excellent electrical performance and extreme sensitivity to chemical species in semiconducting Single-Walled Carbon NanoTubes (s-SWCNTs) motivated the study of using them to replace silicon as a next generation field effect transistor (FET) for electronic, optoelectronic, and biological applications. In addition, use of SWCNTs in the recently studied flexible electronics appears more promising because of SWCNTs’ inherent flexibility and superior electrical performance over silicon-based materials. All these applications require SWCNT-FETs to have a wafer-scale uniform and reliable performance over time to a level that is at least comparable with the currently used silicon-based nanoscale FETs. Due to similarity in device configuration and its operation, SWCNT-FET inherits most of the variability and reliability concerns of silicon-based FETs, namely the ones originating from line edge roughness, metal work-function variation, oxide defects, etc. Additional challenges arise from the lack of chirality control in as-grown and post-processed SWCNTs and also from the presence of unstable hydroxyl (–OH) groups near the interface of SWCNT and dielectric. In this review article, we discuss these variability and reliability origins in SWCNT-FETs. Proposed solutions for mitigating each of these sources are presented and a future perspective is provided in general, which are required for commercial use of SWCNT-FETs in future nanoelectronic applications.

Handbook of RF, Microwave, and Millimeter-Wave Components. Edited by Leonid A. Belov, Sergey M. Smolskiy and Victor N. Kochemasov, Artech House, 2012; 504 pages. Price: £119.00, ISBN 978-1-60807-209-5

Abstract: This unique and comprehensive resource offers you a detailed treatment of the operations principles, key parameters, and specific characteristics of active and passive RF, microwave, and millimeter-wave components. The book covers both linear and nonlinear components that are used in a wide range of application areas, from communications and information sciences, to avionics, space, and military engineering.

High-Feedback Operation of Power Electronic Converters

Abstract: The purpose of this review is to provide a survey of some of the most important bifurcation phenomena that one can observe in pulse-modulated converter systems when operating with high corrector gain factors. Like other systems with switching control, electronic converter systems belong to the class of piecewise-smooth dynamical systems. A characteristic feature of such systems is that the trajectory is “sewed” together from subsequent discrete parts. Moreover, the transitions between different modes of operation in response to a parameter variation are often qualitatively different from the bifurcations we know for smooth systems. The review starts with an introduction to the concept of border-collision bifurcations and also demonstrates the approach by which the full dynamics of the piecewise-linear, time-continuous system can be reduced to the dynamics of a piecewise-smooth map. We describe the main bifurcation structures that one observes in three different types of converter systems: (1) a DC/DC converter; (2) a multi-level DC/DC converter; and (3) a DC/AC converter. Our focus will be on the bifurcations by which the regular switching dynamics becomes unstable and is replaced by ergodic or resonant periodic dynamics on the surface of a two-dimensional torus. This transition occurs when the feedback gain is increased beyond a certain threshold, for instance in Electronics 2013, 2 114 order to improve the speed and accuracy of the output voltage regulation. For each of the three converter types, we discuss a number of additional bifurcation phenomena, including the formation and reconstruction of multi-layered tori and the appearance of phase-synchronized quasiperiodicity. Our numerical simulations are compared with experimentally observed waveforms.

An Energy Conservative Wireless Sensor Networks Approach for Precision Agriculture

Abstract: Reducing energy consumption of sensor nodes to prolong the lifetime of finite-capacity batteries and how to enhance the fault-tolerant ability of networks are the major challenges in design of Wireless Sensor Networks (WSNs). In this paper, we present an energy-efficient system of WSNs for black pepper monitoring in tropical areas. At first, we optimized the base station antenna height in order to facilitate reliable communication, after which the Energy-efficient Sensor Protocol for Information via Negotiation (ESPIN) routing protocol was utilized to solve the energy saving challenge. We conducted radio propagation experiments in actual black pepper fields. The practical test results illustrate that the ESPIN protocol reduces redundant data transmission and whole energy consumption of network, and enhances the success rate of data transmission compared with traditional Sensor Protocol for Information via Negotiation (SPIN) protocol. To further optimize topology for improving the network lifetime, we designed a symmetrical double-chain (SDC) topology which is suitable to be deployed in farmland and compared the lifetime with traditional tree topology. Experiment results indicate SDC topology has a longer network lifetime than traditional tree topology. The system we designed will greatly help farmers to make more informed decisions on the efficient use of resources and hence improve black pepper productivity.

Photovoltaic System Equipped with Digital Command Control and Acquisition

Abstract: In this paper, we present results concerning the design, the realization and the characterization of a photovoltaic system (PV), equipped with a digital controls: Power Point Tracking (MPPT), charge/discharge lead acid batteries, sun tracker and supervision. These different functions are performed with a microcontroller that has capabilities and functions to the reliability of PV systems (signal generation Pulses Width Modulation (PWM), speed etc.). Concerning the MPPT control operation, we improved the accuracy and reliability of research by improving the search algorithm “Hill Climbing” taking into account the optimal operation of PV panels depending on weather conditions (temperature and light).The experiment of each block shows that the MPPT control converges instantly the operating point of the PV panels around the maximum power point, independently of sudden changes of the illumination or the load. The control blocks charge/discharge battery and sun tracking show good control of charge/discharge lead acid batteries and the need of sun tracker to increase the power supplied by the PV panel. By using the improved MPPT control, loss of power supplied by the PV panels are very low (below 5%).

An Efficient Method for Approximation of Non Rational Transfer Functions

Abstract: A method for rational approximation of linear fractional order systems (LFOS) is presented in the present paper. The method is computationally efficient, flexible and effective, as is illustrated by numerous examples. The proposed approach can also be used as an intermediate stage in designing indirect discrete rational approximations.

Digital Controller Development Methodology Based on Real-Time Simulations with LabVIEW FPGAc Hardware-Software Toolset

Abstract: In this paper, we exemplify the use of NI Lab-VIEW FPGA as a rapid prototyping environment for digitalcontrollers. In our power electronics laboratory, it has beensuccessfully employed in the development, debugging, and test ofdifferent power converter controllers for microgrid applications.The paper shows how this high level programming language,together with its target hardware platforms, including CompactRIO and Single Board RIO systems, allows researchers andstudents to develop even complex applications in reasonabletimes. The availability of efficient drivers for the consideredhardware platforms frees the users from the burden of low levelprogramming. At the same time, the high level programmingapproach facilitates software re-utilization, allowing the laboratoryknow-how to steadily grow along time. Furthermore, itallows hardware-in-the-loop real-time simulation, that proved tobe effective, and safe, in debugging even complex hardware andsoftware co-designed controllers. To illustrate the effectiveness ofthese hardware-software toolsets and of the methodology basedupon them, two case studies are presented.

Modeling Radiation-Induced Degradation in Top-Gated Epitaxial Graphene Field-Effect-Transistors (FETs)

Abstract: This paper investigates total ionizing dose (TID) effects in top-gated epitaxial graphene field-effect-transistors (GFETs). Measurements reveal voltage shifts in the current-voltage (I-V) characteristics and degradation of carrier mobility and minimum conductivity, consistent with the buildup of oxide-trapped charges. A semi-empirical approach for modeling radiation-induced degradation in GFETs effective carrier mobility is described in the paper. The modeling approach describes Coulomb and short-range scattering based on calculations of charge and effective vertical field that incorporate radiation-induced oxide trapped charges. The transition from the dominant scattering mechanism is correctly described as a function of effective field and oxide trapped charge density. Comparison with experimental data results in good qualitative agreement when including an empirical component to account for scatterer transparency in the low field regime.

From Theory to Development: Role of Multiphysics Modeling and its Effect on Education in Electronics

Abstract: Electronics engineering is a very rapidly growingfield, as the time passes the requirement of more advance technologiesincrease. There are a lot of institutions and universitiesaround the world that provide quality education to different fieldsof engineering. The courses that electronics engineers study needpractical exposure as well to cope up with industrial demands. Inthis paper, the role of multiphysics modeling and its impact onengineering education is demonstrated. Finite element modeling(FEM) tools are very powerful tools and due to there hugeadvantages, electronics graduates should study these tools in theircourse curriculum to know how to tackle various types of physicsproblems and through examples it is demonstrated that how thesetools can help shift from just theory to development process.

Redundancy + Reconfigurability = Recoverability

Abstract: An approach to consider computers and connected computer systems using structural, time, and information redundancies is proposed. An application of redundancy for reconfigurability and recoverability of computers and connected computer systems is discussed, gaining performance, reliability, and power-saving in operation. A paradigm of recoverability is introduced and, if followed, shifts connected computer systems toward real-time applications. Use of redundancy for connected computers is analysed in terms of recoverability, where two supportive algorithms of forward and backward tracing are proposed and explained. As an example, growth of mission reliability is formulated.

Embroidered Coils for Magnetic Resonance Sensors

Abstract: Magnetic resonance imaging is a widely used technique for medical and materials imaging. Even though the objects being imaged are often irregularly shaped, suitable coils permitting the measurement of the radio-frequency signal in these systems are usually made of solid copper. One problem often encountered is how to ensure the coils are both in close proximity and conformal to the object being imaged. Whilst embroidered conductive threads have previously been used as antennae in mobile telecommunications applications, they have not previously been reported for use within magnetic resonance. In this paper we show that an embroidered single loop coil can be used in a commercial unilateral nuclear magnetic resonance system as an alternative to a solid copper. Data is presented showing the determination of both longitudinal (T1) and effective transverse (T2 eff ) relaxation times for a flat fabric coil and the same coil conformed to an 8 cm diameter cylinder. We thereby demonstrate the principles required for the wider use of fabric based conformal coils within nuclear magnetic resonance and magnetic resonance imaging.

Celebrating 65th Anniversary of the Transistor

Abstract: The paper is dedicated to the 65th anniversary of theinvention of the revolutionary electronic component that actuallychanged our way of life—the transistor. It recounts the keyhistorical moments leading up to the invention of the firstsemiconductor active component in 1947. The meaning of theblend “transistor” is explained using the memorandum issued byBell Telephone Laboratories. Certain problems appeared in theengineering phase of the transistor development and the newcomponents obtained as a result of this research are reviewed.The impact of this invention on the development of powerelectronics is being emphasized. Finally, the possibility that themost important invention of the 20th century has been conceivednot once but twice is discussed.

Design of a Parallel Sampling Encoder for Analog to Information (A2I) Converters: Theory, Architecture and CMOS Implementation

Abstract: We discuss the architecture and design of parallel sampling front ends for analog to information (A2I) converters. As a way of example, we detail the design of a custom 0.5 µm CMOS implementation of a mixed signal parallel sampling encoder architecture. The system consists of configurable parallel analog processing channels, whose output is sampled by traditional analog-to-digital converters (ADCs). The analog front-end modulates the signal of interest with a high-speed digital chipping sequence and integrates the result prior to sampling at a low rate. An FPGA is employed to generate the chipping sequences and process the digitized samples.

Influence of Signal Stationarity on Digital Stochastic Measurement Implementation

Abstract: The paper presents the influence of signal stationarity on digital stochastic measurement method implementation. The implementation method is based on stochastic voltage generators, analog adders, low resolution A/D converter, and multipliers and accumulators implemented by Field-Programmable Gate Array (FPGA). The characteristic of first implementations of digital stochastic measurement was the measurement of stationary signal harmonics over the constant measurement period. Later, digital stochastic measurement was extended and used also when it was necessary to measure time-series of non-stationary signal over the variable measurement time. The result of measurement is the set of harmonics, which is, in the case of non-stationary signals, the input for calculating digital values of signal in time domain. A theoretical approach to determine measurement uncertainty is presented and the accuracy trends with varying signal-to-noise ratio (SNR) are analyzed. Noisy brain potentials (spontaneous and non-spontaneous) are selected as an example of real non-stationary signal and its digital stochastic measurement is tested by simulations and experiments. Tests were performed without noise and with adding noise with SNR values of 10dB, 0dB and -10dB. The results of simulations and experiments are compared versus theory calculations, and comparasion confirms the theory.

Single-Phase Full-Wave Rectifier as an Effective Example to Teach Normalization, Conduction Modes, and Circuit Analysis Methods

Abstract: Application of a single phase rectifier as an example in teaching circuit modeling, normalization, operating modes of nonlinear circuits, and circuit analysis methods is proposed. The rectifier supplied from a voltage source by an inductive impedance is analyzed in the discontinuous as well as in the continuous conduction mode. Completely analytical solution for the continuous conduction mode is derived. Appropriate numer- ical methods are proposed to obtain the circuit waveforms in both of the operating modes, and to compute the performance parameters. Source code of the program that performs such computation is provided.

An Operational Standpoint in Electrical Engineering

Abstract: In electrical engineering education exists a major difficulty for first level students, namely the Laplace transform. The question is: does this ubiquitous tool is needed in an electrical engineering course? Our answer is: Obviously, not. Based on an operational standpoint the paper describes some guidelines and results for a primer on handling signals and linear systems without using the Laplace transform. The main advantage is that the operational standpoint leads to simplified proofs for well-known results.

Study on New Smart Transformer Terminal Unit Based on ARM and GPRS Network

Abstract: Distribution transformer is one of the mostimportant power equipments in distribution network, whoserunning state exercises a great influence on the stability of thenetwork. Transformer Terminal Unit (TTU) is an effective deviceto monitor the running state of transformers in the distributionautomation system. In this paper, we study a new smart TTUwhich uses ARM7 series chip as processor, equipped withATT7022B based electric meter module and GPRS module forremote data transmission control. We focus on the correspondinghardware, software design and the measurement principle ofharmonics of TTU. The new TTU can measure the electricparameters of the distribution transformer precisely. Takingadvantage of the powerful ARM processor, it can analyzeharmonic of the power line effectively. Due to the always-on-linefeature of GPRS, TTU can achieve reliable communication withthe remote terminal and the master station. Compared with othersimilar units, the new unit outperforms in terms of real-time,precision and reliability, which can fully meet with the high-speeddevelopment of distribution automation system.

Far Field Extrapolation from Near Field Interactions and Shielding Influence Investigations Based on a FE-PEEC Coupling Method

Abstract: Regarding standards, it is well established that common mode currents are the main source of far field emitted by variable frequency drive (VFD)-cable-motor associations. These currents are generated by the combination of floating potentials with stray capacitances between these floating potential tracks and the mechanical parts connected to the earth (the heatsink or cables are usual examples). Nowadays, due to frequency and power increases, the systematic compliance to EMC (ElectroMagnetic Compatibility) becomes increasingly difficult and costly for industrials. As a consequence, there is a well-identified need to investigate practical and low cost solutions to reduce the radiated fields of VFD-cable-motor associations. A well-adapted solution is the shielding of wound components well known as the major source of near magnetic field. However, this solution is not convenient, it is expensive and may not be efficient regarding far field reduction. Optimizing the components placement could be a better and cheaper solution. As a consequence, dedicated tools have to be developed to efficiently investigate not easy comprehendible phenomena and finally to control EMC disturbances using component placement, layout geometry, shielding design if needed. However, none of the modeling methods usually used in industry complies with large frequency range and far field models including magnetic materials, multilayer PCBs, and shielding. The contribution of this paper is to show that alternatives regarding modeling solutions exist and can be used to get in-deep analysis of such complex structures. It is shown in this paper that near field investigations can give information on far field behavior. It is illustrated by an investigation of near field interactions and shielding influence using a FE-PEEC hybrid method. The test case combining a common mode filter with the floating potentials tracks of an inverter is based on an industrial and commercialized VFD. The near field interactions between the common mode inductance and the tracks with floating potentials are revealed. Then, the influence of the common mode inductance shielding is analyzed.

Project-Based Learning and Agile Methodologies in Electronic Courses: Effect of Student Population and Open Issues

Abstract: Project-Based Learning (PBL) and Agile methodologieshave proven to be very interesting instructional strategiesin Electronics and Engineering education, because they providepractical learning skills that help students understand the basisof electronics. In this paper we analyze two courses, onebelonging to a Master in Electronic Engineering and one to aBachelor in Telecommunication Engineering that apply Agile-PBL methodologies, and compare the results obtained in bothcourses with a traditional laboratory course. Our results supportprevious work stating that Agile-PBL methodologies increasestudent satisfaction. However, we also highlight some open issuesthat negatively affect the implementation of these methodologies,such as planning overhead or accidental complexity. Moreover,we show how differences in the student population, mostly relatedto the time spent on-campus, their commitment to the course orpart-time dedication, have an impact on the benefits of Agile-PBLmethods. In these cases, Agile-PBL methodologies by themselvesare not enough and need to be combined with other techniquesto increase student motivation.

Analysis and Design of a Higher Current ZVS-PWM Converter for Industrial Applications

Abstract: A new auxiliary circuit that can be implemented in DC-DC and AC-DC ZVS-PWM converters is proposed in the paper. The circuit is for ZVS-PWM converters used in applications where high-frequency operation is needed and the load current is higher than that of typical ZVS-PWM converters. In the paper, the operation of a new ZVS-PWM converter is described, its steady-state operation is analyzed, and a procedure for its design is derived and then demonstrated. The feasibility of the new converter is confirmed by experimental results obtained from a prototype.

A Realization of Temperature Monitoring System Based on Real-Time Kernel μC/OS and 1-wire Bus

Abstract: The traditional temperature monitoring system generally adopt some analog sensors for collecting data and a microcontroller for processing data for the purpose of temperature monitoring. However, this back-fore ground system has the disadvantages that the system has poor real-time property and single function, the amount of sensors is not easy to expand, and the software system has a difficulty in upgrading. Aiming at these disadvantages, the system designed in this paper adopts brand-new hardware and software structures: a digital temperature sensor array is connected to 1-wire bus and communicated with a control core through 1-wire bus protocol, thus a great convenience is provided for the expansion of the sensor; a real-time operating system is introduced into the software, an application program capable of realizing various functions runs on the real-time kernel μC/OS-II platform. The application of the real-time kernel also provides a good lower layer interface for the late-stage software upgrading.

Tool-Based Curricula and Visual Learning

Abstract: In the last twenty years nanotechnology hasrevolutionized the world of information theory, computers andother important disciplines, such as medicine, where it hascontributed significantly in the creation of more sophisticateddiagnostic tools. Therefore, it is important for people working innanotechnology to better understand basic concepts to be morecreative and productive. To further foster the progress onNanotechnology in the USA, the National Science Foundation hascreated the Network for Computational Nanotechnology (NCN)and the dissemination of all the information from member andnon-member participants of the NCN is enabled by thecommunity website www.nanoHUB.org. nanoHUB’s signatureservices online simulation that enables the operation ofsophisticated research and educational simulation engines with acommon browser. No software installation or local computingpower is needed. The simulation tools as well as nano-conceptsare augmented by educational materials, assignments, and toolbasedcurricula, which are assemblies of tools that help studentsexcel in a particular area.As elaborated later in the text, it is the visual mode of learningthat we are exploiting in achieving faster and better results withstudents that go through simulation tool-based curricula. Thereare several tool based curricula already developed on thenanoHUB and undergoing further development, out of which fiveare directly related to nanoelectronics. They are: ABACUS –device simulation module; ACUTE – Computational Electronicsmodule; ANTSY – bending toolkit; and AQME – quantummechanics module. The methodology behind tool-based curriculais discussed in details. Then, the current status of each module ispresented, including user statistics and student learningindicatives. Particular simulation tool is explored further todemonstrate the ease by which students can grasp information.Representative of Abacus is PN-Junction Lab; representative ofAQME is PCPBT tool; and representative of ACUTE isSCHRED, which has 97 citations in research papers and is themost popular tool on nanoHUB.org.Surveys were collected from three courses offered at ArizonaState University. These courses were: EEE434/591, the QuantumMechanics class offered in the fall 2007; EEE 101 EngineeringDesign, offered in the spring 2008; and EEE533 SemiconductorManuscript received 2 December 2013. Received in revised form 25December 2013. Accepted for publication 26 December 2013.This work was financially supported from NSF Grant under grant No. NSFECS 0901251 is also acknowledged.This work was presented at the 9th, European conference on e-Learning(2010).Dragica Vasileska is with the Arizona State University, Tempe, AZ USA(phone: +1-480-965-6651; e-mail: Vasileska@asu.edu).Gerhard Klimeck is with Purdue University, West Lafayette, IN USA (email:gekco@purdue.edu).A. Magana is with Purdue University, West Lafayette, IN USA (e-mail:admagana@purdue.edu).S. M. Goodnick is with the Arizona State University, Tempe, AZ USA (email:stephen.goodnick@asu.edu).Device and Process Simulation, offered in the fall 2009. Thestudy consisted of students participating in a voluntary Likertscalesurvey that focused on: Learning outcomes, Evidence of thelearning, Pedagogical approach and Usability aspects. Inparticular, the survey investigated how intuitive the tools are.The results of the study identified differences in the waystudents perceived the nanoHUB.org simulation tools. Graduateand undergraduate students reported more positive experienceswith nanoHUB.org simulations than freshman students did.Potential explanations for these differences are: a) freshmanstudents have not fully developed graphical literacy skills; b)students may lack the prior knowledge required at the time theyinteract with the tool; and c) students may lack interests in thetopic and have not yet seen the value of how these tools can beapplied toward their own learning goals. A potential support toovercome some of these difficulties may be by embedding just-intimeinstructional supports together with the simulation tools.

Effects of Localized Trap-States and Corrugation on Charge Transport in Graphene Nanoribbons

Abstract: We investigate effects of the electron traps on adiabatic charge transport in graphene nanoribbons under a longitudinal surface acoustic wave (SAW) potential. Due to the weak SAW potential and strong transverse confinement of nanoribbons, minibands of sliding tunnel-coupled quantum dots are formed. Therefore, as the chemical potential passes through minigaps, quantized adiabatic charge transport is expected to occur. We analyze the condition for a closed minigap, thereby destroying the current quantization in a nanoribbon. We present numerical calculations showing the localized energy states within minigaps. Additionally, we compare the results with the minibands of corrugated nanoribbons.