42 research outputs found

    Mixed-Domain Fast Simulation of RF and Microwave MEMS-based Complex Networks within Standard IC Development Frameworks

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    MS technology (MicroElectroMechanical-System) has been successfully employed since a few decades in the sensors/actuators field. Several products available on the market nowadays include MEMS-based accelerometers and gyroscopes, pressure sensors and micro-mirrors matrices. Beside such well-established exploitation of MEMS technology, its use within RF (Radio Frequency) blocks and systems/sub-systems has been attracting, in recent years, the interest of the Scientific Community for the significant RF performances boosting that MEMS devices can enable. Several significant demonstrators of entirely MEMS-based lumped components, like variable capacitors (Hyung et al., 2008), inductors (Zine-El-Abidine et al., 2003) and micro-switches (Goldsmith et al., 1998), are reported in literature, exhibiting remarkable performance in terms of large tuning-range, very high Q-Factor and low-loss, if compared with the currently used components implemented in standard semiconductor technology (Etxeberria & Gracia, 2007, Rebeiz & Muldavin, 1999). Starting from the just mentioned basic lumped components, it is possible to synthesize entire functional sub-blocks for RF applications in MEMS technology. Also in this case, highly significant demonstrators are reported and discussed in literature concerning, for example, tuneable phase shifters (Topalli et al., 2008), switching matrices (Daneshmand & Mansour, 2007), reconfigurable impedance matching networks (Larcher et al., 2009) and power attenuators (Iannacci et al., 2009, a). In all the just listed cases, the good characteristics of RF-MEMS devices lead, on one side, to very highperformance networks and, on the other hand, to enabling a large reconfigurability of the entire RF/Microwave systems employing MEMS sub-blocks. In particular, the latter feature addresses two important points, namely, the reduction of hardware redundancy, being for instance the same Power Amplifier within a mobile phone suitable both in transmission (Tx) and reception (Rx) (De Los Santos, 2002), and the usability of the same RF apparatus in compliance with different communication standards (like GSM, UMTS, WLAN and so on) (Varadan, 2003). Beside the exploitation of MEMS technology within RF transceivers, other potentially successful uses of Microsystems are in the Microwave field, concerning, e.g., very compact switching units, especially appealing to satellite applications for the very reduced weight (Chung et al., 2007), and phase shifters in order to electronically steer short and mid-range radar systems for the homeland security and monitoring applications (Maciel et al., 2007). Given all the examples reported above, it is straightforward that the employment of a proper strategy in aiming at the RF-MEMS devices/networks optimum design is a key-issue in order to gain the best benefits, in terms of performance, that such technology enables to address. This is not an easy task as the behaviour of RF-MEMS transversally crosses different physical domains, namely, electrical, mechanical and electromagnetic, leading to a large number of trade-offs between mechanical and electrical/electromagnetic parameters, that typically cannot be managed within a unique commercial simulation tool. In this chapter, a complete approach for the fast simulation of single RF-MEMS devices as well as of complex networks is presented and discussed in details. The proposed method is based on a MEMS compact model library, previously developed by the author, within a commercial simulation environment for ICs (integrated circuits). Such software tool describes the electromechanical mixed-domain behaviour typical of MEMS devices. Moreover, through the chapter, the electromagnetic characteristics of RF-MEMS will be also addressed by means of extracted lumped element networks, enabling the whole electromechanical and electromagnetic design optimization of the RF-MEMS device or network of interest. In particular, significant examples about how to acc..

    Connecting vehicular networks to the internet : a life time-based routing protocol

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    Inter-Vehicle Communications have recently attracted the attention of researchers in academia and industry. In such networks, vehicles should be able to communicate among each other (V2V) as well as with roadside Infrastructure units (V2I). Vehicular networks try to provide safety on the roads by disseminating critical messages among vehicles. Infrastructure units provide some services such as driver information systems and Internet access. Because of the high speed and high mobility of vehicles, establishing and maintaining a connection to these units is very challenging. We introduce a new protocol that uses the characteristics of vehicle movements to predict the vehicle behavior and select a route with the longest life-time to connect to the wired network. It aims at spreading the advertisement messages through multi-hops without flooding the network, do seamless hand-overs and select the most stable routes to these units. We performed some simulations and compared the performance of our work with some well-known protocols

    FogLearn: Leveraging Fog-based Machine Learning for Smart System Big Data Analytics

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    Big data analytics with the cloud computing are one of the emerging area for processing and analytics. Fog computing is the paradigm where fog devices help to reduce latency and increase throughput for assisting at the edge of the client. This paper discussed the emergence of fog computing for mining analytics in big data from geospatial and medical health applications. This paper proposed and developed fog computing based framework i.e. FogLearn for application of K-means clustering in Ganga River Basin Management and realworld feature data for detecting diabetes patients suffering from diabetes mellitus. Proposed architecture employed machine learning on deep learning framework for analysis of pathological feature data that obtained from smart watches worn by the patients with diabetes and geographical parameters of River Ganga basin geospatial database. The results showed that fog computing hold an immense promise for analysis of medical and geospatial big data

    III-V Nanowire MOSFET High-Frequency Technology Platform

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    This thesis addresses the main challenges in using III-V nanowireMOSFETs for high-frequency applications by building a III-Vvertical nanowire MOSFET technology library. The initial devicelayout is designed, based on the assessment of the current III-V verticalnanowire MOSFET with state-of-the-art performance. The layout providesan option to scale device dimensions for the purpose of designing varioushigh-frequency circuits. The nanowire MOSFET device is described using1D transport theory, and modeled with a compact virtual source model.Device assessment is performed at high frequencies, where sidewall spaceroverlaps have been identified and mitigated in subsequent design iterations.In the final stage of the design, the device is simulated with fT > 500 GHz,and fmax > 700 GHz.Alongside the III-V vertical nanowire device technology platform, adedicated and adopted RF and mm-wave back-end-of-line (BEOL) hasbeen developed. Investigation into the transmission line parameters revealsa line attenuation of 0.5 dB/mm at 50 GHz, corresponding to state-ofthe-art values in many mm-wave integrated circuit technologies. Severalkey passive components have been characterized and modeled. The deviceinterface module - an interconnect via stack, is one of the prominentcomponents. Additionally, the approach is used to integrate ferroelectricMOS capacitors, in a unique setting where their ferroelectric behavior iscaptured at RF and mm-wave frequencies.Finally, circuits have been designed. A proof-of-concept circuit, designedand fabricated with III-V lateral nanowire MOSFETs and mm-wave BEOL, validates the accuracy of the BEOL models, and the circuit design. Thedevice scaling is shown to be reflected into circuit performance, in aunique device characterization through an amplifier noise-matched inputstage. Furthermore, vertical-nanowire-MOSFET-based circuits have beendesigned with passive feedback components that resonate with the devicegate-drain capacitance. The concept enables for device unilateralizationand gain boosting. The designed low-noise amplifiers have matching pointsindependent on the MOSFET gate length, based on capacitance balancebetween the intrinsic and extrinsic capacitance contributions, in a verticalgeometry. The proposed technology platform offers flexibility in device andcircuit design and provides novel III-V vertical nanowire MOSFET devicesand circuits as a viable option to future wireless communication systems

    Robotic Percutaneous Coronary Intervention in Coronary Heart Disease: Applications and Recent Advances

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    Traditional percutaneous coronary intervention (T-PCI) has long been an effective method for treating coronary heart disease (CHD), but the radiation hazards and orthopedic injuries among T-PCI operators are concerning. These problems have been mitigated with the emergence of robotic percutaneous coronary intervention (R-PCI), which is expected to increase intervention accuracy and safety. In this review, we first summarize the current status of PCI development, including robot systems, and PCI application and evaluation. Second, we compare T-PCI and R-PCI to identify the benefits for patients and physicians. In addition, we describe a new R-PCI system, R-PCI WSER-CD01, which incorporates multi-instrument collaborative delivery and provides full-process assistance in minimally invasive vascular intervention. This system introduces three key innovations that address safety concerns, and improve the accuracy, wire compatibility, and remote operation capabilities of existing of vascular intervention robot systems. Finally, we discuss prospects for the development of R-PCI. As an emerging technology, R-PCI aligns well with the trends of precision medicine and telemedicine, and therefore warrants continued innovation

    Quality-Driven Cross-Layer Protocols for Video Streaming over Vehicular Ad-Hoc Networks

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    The emerging vehicular ad-hoc networks (VANETs) offer a variety of applications and new potential markets related to safety, convenience and entertainment, however, they suffer from a number of challenges not shared so deeply by other types of existing networks, particularly, in terms of mobility of nodes, and end-to-end quality of service (QoS) provision. Although several existing works in the literature have attempted to provide efficient protocols at different layers targeted mostly for safety applications, there remain many barriers to be overcome in order to constrain the widespread use of such networks for non-safety applications, specifically, for video streaming: 1) impact of high speed mobility of nodes on end-to-end QoS provision; 2) cross-layer protocol design while keeping low computational complexity; 3) considering customer-oriented QoS metrics in the design of protocols; and 4) maintaining seamless single-hop and multi-hop connection between the destination vehicle and the road side unit (RSU) while network is moving. This thesis addresses each of the above limitations in design of cross-layer protocols for video streaming application. 1) An adaptive MAC retransmission limit selection scheme is proposed to improve the performance of IEEE 802.11p standard MAC protocol for video streaming applications over VANETs. A multi-objective optimization framework, which jointly minimizes the probability of playback freezes and start-up delay of the streamed video at the destination vehicle by tuning the MAC retransmission limit with respect to channel statistics as well as packet transmission rate, is applied at road side unit (RSU). Two-hop transmission is applied in zones in which the destination vehicle is not within the transmission range of any RSU. In the multi-hop scenario, we discuss the computation of access probability used in the MAC adaptation scheme and propose a cross-layer path selection scheme; 2) We take advantage of similarity between multi-hop urban VANETs in dense traffic conditions and mesh connected networks. First, we investigate an application-centric routing scheme for video streaming over mesh connected overlays. Next, we introduce the challenges of urban VANETs compared to mesh networks and extend the proposed scheme in mesh network into a protocol for urban VANETs. A classification-based method is proposed to select an optimal path for video streaming over multi-hop mesh networks. The novelty is to translate the path selection over multi-hop networks to a standard classification problem. The classification is based on minimizing average video packet distortion at the receiving nodes. The classifiers are trained offline using a vast collection of video sequences and wireless channel conditions in order to yield optimal performance during real time path selection. Our method substantially reduces the complexity of conventional exhaustive optimization methods and results in high quality (low distortion). Next, we propose an application-centric routing scheme for real-time video transmission over urban multi-hop vehicular ad-hoc network (VANET) scenarios. Queuing based mobility model, spatial traffic distribution and prob- ability of connectivity for sparse and dense VANET scenarios are taken into consideration in designing the routing protocol. Numerical results demonstrate the gain achieved by the proposed routing scheme versus geographic greedy forwarding in terms of video frame distortion and streaming start-up delay in several urban communication scenarios for various vehicle entrance rate and traffic densities; and 3) finally, the proposed quality-driven routing scheme for delivering video streams is combined with a novel IP management scheme. The routing scheme aims to optimize the visual quality of the transmitted video frames by minimizing the distortion, the start-up delay, and the frequency of the streaming freezes. As the destination vehicle is in motion, it is unrealistic to assume that the vehicle will remain connected to the same access router (AR) for the whole trip. Mobile IP management schemes can benefit from the proposed multi-hop routing protocol in order to adapt proxy mobile IPv6 (PMIPv6) for multi-hop VANET for video streaming applications. The proposed cross-layer protocols can significantly improve the video streaming quality in terms of the number of streaming freezes and start-up delay over VANETs while achieving low computational complexity by using pattern classification methods for optimization

    中性子捕獲ガンマ線反応における空間反転対称性の破れ

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    本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである京都大学0048新制・課程博士博士(理学)甲第4931号理博第1350号新制||理||755(附属図書館)UT51-92-B107京都大学大学院理学研究科物理学第二専攻(主査)教授 政池 明, 教授 玉垣 良三, 教授 井上 信学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

    Bioconjugation Techniques to construct Spontaneously assembling DNA-Enzyme Macromolecules

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    In the past two decades, crosslinking has been a popular choice in synthesizing bioconjugatesinthefieldsofbiotechnology,medicaldiagnostics,andgeneticscreening.However, their efficacyin synthesizing the desired bioconjugates is scarcely analyzed and documented. The scope of this investigation encompassed studying covalent bioconjugation techniques, and determining the structural characteristics of the bioconjugates formed via several crosslinking strategies. The major goal of the study was to determine relatively inexpensive, less complex, and universal bioconjugation techniques with the flexibility to control the distance between wild-type enzymes. In this investigation, three different crosslinkers were studied to determine the efficacy of crosslinking biological molecules. In the first aim of the study, an adapted strategy from the conventional 1-ethyl-3-(3dimethylaminopropyl) carbodiimide hydrochloride (EDC) was developed to form a novel phosphoramidated single stranded DNA (ssDNA) bioconjugate. Matrix-assisted laser desorption/ionization time-of-flight(MALDI-TOF) was used to determine the molecular weights, and the stability of the bioconjugates formed. A reversed phase high performance liquid chromatography(RP-HPLC)analytical method was developed to determine the conjugate product yields. The analytical procedure’s accuracy, precision, linearity, limit of detection (LOD), and limit of quantitation (LOQ) were determined. Afterwards, the yield of the phosphoramidated ssDN Abioconjugate was determined using the developed analytical procedure. In our attempts to determine suitable crosslinkers, another crosslinker (BS3) was also investigated to accomplish bioconjugation between ssDNA, and a small peptide. However, mass spectrometry results indicated conjugate molecular weights evidencing only partial bioconjugate formation. In the next aim, the successful adapted EDC crosslinking technique was applied to two wild-type enzymes to synthesize enzyme-single stranded DNA (enzyme-ssDNA) bioconjugates, in an aqueous system. Like so, glucose oxidase-ssDNA4 (GOD-ssDNA4), and horseradish peroxidase-ssDNA3 (HRP-ssDNA3) conjugates were synthesized separately. These enzymessDNA conjugates were analyzed, and purified using size exclusion chromatography (SEC). Fluorescence spectroscopy was used to determine the presence of ssDNA in the GOD-ssDNA4 bioconjugates, while MALDI-TOF spectrometry was used to determine the molecular weights of the HRP-ssDNA3 bioconjugates. Altogether, size exclusion chromatography, fluorescence spectroscopy, and MALDI-TOF results suggest that the adapted EDC crosslinking method was successful in producingthe expected enzyme-ssDNA conjugates. In order to spontaneously assemble the GOD-ssDNA4, and HRP-ssDNA3 bioconjugates, DNA hybridization was utilized. However, high annealing temperatures used in the general heating-cooling protocols has the potential to degenerate these enzyme conjugates. Therefore, possibilities of accomplishing DNA hybridization at lowered annealing temperatures was investigated as well. After facilitating DNA hybridization between GOD-ssDNA4 and HRPssDNA3, the final enzymatic macromolecule was analyzed on size exclusion chromatography. Based on the structural evidence obtained from mass spectrometry, UV-Vis spectrophotometry, reversed phase chromatography, size exclusion chromatography, and fluorescence spectroscopy, we analyzed the desired bioconjugates at each successive stage in this bottom-up-synthesis

    Experimental Assessment and Enhancement of Planar Laser-Induced Fluorescence Measurements of Nitric Oxide in an Inverse Diffusion Flame

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    We have experimentally assessed the quantitative nature of planar laser-induced fluorescence (PLIF) measurements of NO concentration in a unique atmospheric pressure, laminar, axial inverse diffusion flame (IDF). The PLIF measurements were assessed relative to a two-dimensional array of separate laser saturated fluorescence (LSF) measurements. We demonstrated and evaluated several experimentally-based procedures for enhancing the quantitative nature of PLIF concentration images. Because these experimentally-based PLIF correction schemes require only the ability to make PLIF and LSF measurements, they produce a more broadly applicable PLIF diagnostic compared to numerically-based correction schemes. We experimentally assessed the influence of interferences on both narrow-band and broad-band fluorescence measurements at atmospheric and high pressures. Optimum excitation and detection schemes were determined for the LSF and PLIF measurements. Single-input and multiple-input, experimentally-based PLIF enhancement procedures were developed for application in test environments with both negligible and significant quench-dependent error gradients. Each experimentally-based procedure provides an enhancement of approximately 50% in the quantitative nature of the PLIF measurements, and results in concentration images nominally as quantitative as LSF point measurements. These correction procedures can be applied to other species, including radicals, for which no experimental data are available from which to implement numerically-based PLIF enhancement procedures
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