Browsing by Type "Conference Publication"
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- PublicationA 0.5ps 1.4mW 50MS/s Nyquist bandwidth time amplifier based two-step flash-ΔΣ time-to-digital converterWe propose a 50-MS/s two-step flash-ΔΣ time-todigital converter (TDC) using stable time amplifiers (TAs).The TDC demonstrates low-levels of shaped quantization noise. The system is simulated in 40-nm CMOS and consumes 1.3 mA from a 1.1 V supply. The bandwidth is broadened to Nyquist rate. At frequencies below 25 MHz, the integrated TDC error is as low as 143 fsrms, which is equal to an equivalent TDC resolution of 0.5 ps.
394Scopus© Citations 2
- PublicationA 0.5V 0.5mW switching current source oscillatorThis paper proposes a new RF oscillator topology that is suitable for ultra-low voltage and power applications. By employing alternating current source transistors, the structure combines the benefits of low supply voltage operation of conventional NMOS cross-coupled oscillators together with high current efficiency of the complementary push-pull oscillators. In addition, the 1/f noise upconversion is also reduced. The 40nm CMOS prototype exhibits an average FoM of 189.5 dBc/Hz over 4–5 GHz tuning range, dissipating 0.5mW from 0.5V power supply, while abiding by the technology manufacturing rules.
569Scopus© Citations 14
- PublicationA 1.8–2.3 GHz broadband Doherty power amplifier with a minimized impedance transformation ratioIn this paper, the design and measurement results of a 1.8 GHz to 2.3 GHz broadband Doherty power amplifier (DPA) are reported. A modified load modulation network is designed to minimize impedance transformation ratio over the entire dynamic range for the purpose of extending the operating bandwidth. Experimental results show that the drain efficiency of the proposed DPA maintains above 50% and 63% with continuous wave input signal powers of 26 dBm and 34 dBm, respectively, from 1.8 GHz to 2.3 GHz. When stimulated by a 60-MHz, 12- carrier UMTS signal at 2.14 GHz, the proposed DPA achieved an average efficiency of 53% at 7.6 dB back-off, while the corresponding adjacent channel leakage ratio is linearized to -48.4 dBc with digital predistortion.
408Scopus© Citations 4
- PublicationA 1/f noise upconversion reduction technique applied to class-D and class-F oscillatorsThe 1/f (flicker) noise upconversion degrades the close-in spectrum of CMOS RF oscillators. The resulting 1/f3 phase noise (PN) can be an issue in PLLs with a loop bandwidth of <;1MHz, which practically implies all cellular phones. A previously published noise-filtering technique  and adding resistors in series with gm-device drains  have shown significant reduction of the 1/f3 oscillator PN corner. However, the former needs an additional tunable inductor and the latter degrades PN in the 20dB/dec region.
1137Scopus© Citations 39
- PublicationA 15-μW, 103-fs step, 5-bit capacitor-DAC-based constant-slope digital-to-time converter in 28nm CMOSThis paper proposes a power-efficient capacitor-array-based digital-to-time converter (DTC) using a constant-slope approach. Fringe-capacitor-based digital-to-analog converter (C-DAC) array is used to regulate starting supply voltage of the constant slope fed to a fixed threshold comparator. The proposed DTC consumes only 15 μW from a 1V supply, while achieving fine resolution of 103 fs when running at 40 MHz. The measured INL and DNL are 0.73/0.35 LSB within a 5-bit range. The DTC achieves the best figure-of-merit of 8.5 fJ among state-of-the-art when normalizing the product of power and INL to the product of input frequency and range.
683Scopus© Citations 12
- PublicationA 2.0–2.5 GHz frequency-selectable oscillator for digital predistortion model identification of RF power amplifiersThis paper presents the design of a frequency selectable oscillator used as part of a new data acquisition architecture for digital predistortion (DPD) of RF power amplifiers (PAs). The proposed architecture aims to alleviate the requirement of high sampling rate analog-to-digital-converters (ADCs) in the data acquisition loop. The oscillator utilizes switchable capacitors with a digital control scheme and is capable of operating between 2.0 GHz and 2.5 GHz with an approximate frequency step size of 512 kHz.
334Scopus© Citations 1
- Publication2.7 Ga plume associated VMS mineralization in the Eastern Goldfields Superterrane: insights from the Ag-Zn-(Au) Nimbus depositEconomic volcanic - hosted massive sulfide (VHMS) deposits of the Archean Yilgarn Craton, Western Australia, are restricted to zones of juvenile crust as revealed through regional Nd, Pb and Hf isotopic variations and the geochemistry of felsic volcanic rocks. Interpreted as Archean paleo - rift zones, one of these runs N - S through the Eastern Goldfields Superterrane (broadly coincident with the Kurnalpi Terrane) and is associated with the high grade ca. 2690 Ma Teutonic Bore, Jaguar and Bentley deposits, plus sub - economic VHMS mineralization further south. To date, only small, historic Cu deposits (e.g. Anaconda) and barren pyritic lenses have been recognised in the older 2.7 Ga plume - dominated lower stratigraphy of the Eastern Goldfields.
- Publication2010 EFFoST Annual Meeting, Dublin(Elsevier, 2011)The 2010 Annual Meeting of the European Federation of Food Science and Technology (EFFoST) took place in Dublin, Ireland on 10-12 November. Twenty four papers and 275 posters were presented, and there were 290 attendees. The theme of the Conference was 'Food and Health'. There were five oral sessions: (i) Nutrition and Health; (ii) Functional Foods [a]; (iii) Functional Foods [b]; (iv) Processing for Healthy Foods, and (v) Food Safety and Health. The poster sessions corresponded to these themes.
- Publication2011 EFFoST Annual Meeting, Berlin(Elsevier, 2012)The 2011 European Federation of Food Science and Technology (EFFoST) conference took place in Berlin, Germany on 9-11 November. The conference programme centred on food process-structure-function relationships and the content was closely allied to the research agenda of the European Technology Platform: Food for Life. There were 16 keynote/review lectures, 38 other oral presentations, 260 posters, and close to 300 attendees. The oral sessions corresponded to the process-structure-function themes as did the poster sessions.
- PublicationA 28-GHz Switched-Filter Phase Shifter with Fine Phase-Tuning Capability Using Back-Gate Biasing in 22-nm FD-SOI CMOSThis paper introduces a phase shifter based on switched filters for mm-wave 5G MIMO transmitters. It is realized in 22 nm FD-SOI CMOS and exploits the use of back-gate biasing. The new approach features strong tolerance to process, voltage and temperature (PVT) variations and thus can maintain low phase error with fine phase tuning capability supporting a large bandwidth. Measurement results show that the 4-bit phase shifter achieves 3.5° rms phase error at 28 GHz. The proposed phase shifter can maintain <5° of the worst-case rms phase error when operating across 24 to 29.5 GHz resulting in 20.56% fractional bandwidth which is the largest among the published switched-filter phase shifters to date.
160Scopus© Citations 1
- Publication28/38 GHz Dual-band Dual-polarized Highly Isolated Antenna for 5G Phased Array ApplicationsThis paper proposed a new dual-band dual-polarized array antenna operating at 28 GHz and 38 GHz for 5G communication applications. Three stacked patches are adopted to achieve the dual-band operation. The lower band from 27.48 to 28.50 GHz is achieved by using the lower large patch, which is couple-fed by the middle patch. While the upper band from 36.94 to 40.43 GHz is achieved by using the middle and upper patches. The two patches resonant at 38 and 40 GHz respectively and the two resonant modes coupled together, which greatly enhances the upper band. To increase the polarization isolation in the lower band, a shorting pin connecting the lower patch and ground is utilized. Taking advantages of the multi-layer technology, the position of the vertical feeding probe between the middle patch and lower patch is slightly shifted to ensure the good impedance matching in both lower band and upper band. For the antenna element, the simulated -12 dB bandwidths are 27.48-28.50 GHz and 36.94-40.43 GHz for the two bands, respectively. The in-band gains are over 6 dBi in the lower band, and over 4 dBi in the upper band. For the 2×2 antenna array, the isolations are better than 20 dB in both bands.
1494Scopus© Citations 12
- Publication2D Non-separable Linear Canonical Transform (2D-NS-LCT) based cryptographyThe 2D non-separable linear canonical transform (2D-NS-LCT) can describe a variety of paraxial optical systems. Digital algorithms to numerically evaluate the 2D-NS-LCTs are not only important in modeling the light field propagations but also of interest in various signal processing based applications, for instance optical encryption. Therefore, in this paper, for the first time, a 2D-NS-LCT based optical Double-random-Phase-Encryption (DRPE) system is proposed which offers encrypting information in multiple degrees of freedom. Compared with the traditional systems, i.e. (i) Fourier transform (FT); (ii) Fresnel transform (FST); (iii) Fractional Fourier transform (FRT); and (iv) Linear Canonical transform (LCT), based DRPE systems, the proposed system is more secure and robust as it encrypts the data with more degrees of freedom with an augmented key-space.
- PublicationA 30-GHz Class-F23 Oscillator in 28nm CMOS using harmonic extraction and achieving 120 kHz l/f3 CornerThis paper presents a mmW frequency generation stage aimed at minimizing phase noise via waveform shaping and harmonic extraction while suppressing flicker noise upconversion via proper harmonic terminations. A second-harmonic tank resonance is assisted by a proposed embedded decoupling capacitor inside a transformer for shortest and well controlled common-mode current return path. Class-F operation with third-harmonic boosting and extraction techniques allow maintaining high quality factor of a 10 GHz tank at the 30 GHz frequency generation while providing implicit divide-by-3 functionality. The proposed 27.3-31.2 GHz oscillator is implemented in 28-nm CMOS. It achieves phase noise of-106 dBc/Hz at 1-MHz offset and figure-of-merit (FoM) of -184 dB at 27.3GHz. Its flicker phase-noise (1/f3) corner of 120 kHz is an order-of-magnitude better than currently achievable at mmW.
367Scopus© Citations 12
- PublicationA 3D computational fluid dynamics validation study for the Queensferry Crossing Bridge with bus models on the deckIn this paper, 3D CFD models of a bridge section of the Queensferry Crossing Bridge including a bus and other secondary structures on the deck are developed in OpenFOAM using the k-ω-SST turbulence model to determine the aerodynamic coefficients. The aerodynamic performance of the bridge deck accounting for several angles of attack with the bus located in various traffic lanes is investigated. The models are then validated with wind tunnel test results and good agreement is found between the 3D CFD models and the wind tunnel tests. The importance of the validated models is that they can be used in the future to study what wind speed should be set as a limit to prevent high-sided vehicles from overturning on the Queensferry Crossing Bridge.
- Publication3D Location and Orientation Estimation using Angle of ArrivalThis paper discusses the problem of joint location and orientation estimation of a receiver using only angle of arrival (AOA) information. Conventional formulations of the problem consist of a number of nonlinear equations where the number of unknowns exceeds the number of equations. However, formulations presented in this paper simplifies the problem in a way that leads of efficient solutions. Two solutions are presented and their performance is compared via simulations using an indoor application as an example. Results emphasize the effectiveness of the the proposed methods.
388Scopus© Citations 5
- Publication50 Years of CS1 at SIGCSE: A Review of the Evolution of Introductory Programming Education ResearchThe SIGCSE Technical Symposium is celebrating its 50th year, and a constant theme throughout this history has been to better understand how novices learn to program. In this paper, we present a perspective on the evolution of introductory programming education research at the Symposium over these 50 years. We also situate the Symposium’s impact in the context of the wider literature on introductory programming research. Applying a systematic approach to collecting papers presented at the Symposium that focus on novice programming / CS1, we categorized hundreds of papers according to their main focus, revealing important introductory programming topics and their trends from 1970 to 2018. Some of these topics have faded from prominence and are less relevant today while others, including many topics focused on students—such as making learning programming more appropriate from gender, diversity, accessibility and inclusion standpoints—have garnered significant attention more recently.We present discussions on these trends and in doing so, we provide a checkpoint for introductory programming research. This may provide insights for future research on how we teach novices and how they learn to program.
982Scopus© Citations 60
- PublicationA 60 GHz 25% tuning range frequency generator with implicit divider based on third harmonic extraction with 182 dBc/Hz FoMA 60 GHz frequency generator with implicit ÷3 divider is proposed in this work to improve the system-level efficiency and phase noise. A third-harmonic boosting technique is utilized to simultaneously generate 20GHz and sufficiently strong 60 GHz signals in order to avoid any divider operating at 60 GHz. The prototype is fabricated in 40nm CMOS and exhibits a phase noise of −100 dBc/Hz at 1MHz offset from 60 GHz carrier and 25% tuning range. The phase noise and FoMT (figure-of-merit with tuning range) are improved by 5 dB and 4.6 dB, respectively, compared to state-of-the-art.
591Scopus© Citations 11
- PublicationAbatement and allocation in the pilot phase of the EU ETSWe use historical industrial emissions data to assess the level of abatement and overallocation that took place across European countries during the pilot phase (2005-2007) of the European Union Emission Trading Scheme. Using a dynamic panel data model, we estimate the counterfactual (business-as-usual) emissions scenario for EU member states. Comparing this baseline to allocated and verified emissions, we conclude that both overallocation and abatement occurred, along with under-allocation and emissions inflation. Over the three trading years of the pilot phase we find over-allocation of approximately 376 million EUAs (6%) and total abatement at the member state level of 107 Mt CO2 (1.8%). However, due to over-allocation and possible uncertainty about future allocation methodologies, we calculate that emissions inflation of approximately 119 Mt CO2 (2%) occurred, resulting in emissions over the pilot phase being approximately 12 Mt CO2 (0.2%) higher than they would have been in the absence of the EU ETS.
- PublicationAbbreviation and Acronym Identification and Expansion Within Medical Health RecordsRecent years have seen the rapid increase in digitised medical information. In particular, the massive expansion of Electronic Health Records (EHRs), which are designed to document all information that is clinically relevant in a patient's use of a healthcare facility, has introduced unprecedented volumes of relatively unstructured data. This paper intends to determine the extent to which knowledge discovery in relation to both abbreviations and acronyms within heterogeneous data can be achieved. Heterogeneous data such as the narrative-based free-text notes found within patients' EHRs may use inconsistent ways to indicate contractions within the text and may use non-standard definitions for both abbreviations and acronyms. We approached this task through the retrieval and classification of contractions as well as using a novel method of combining multiple publically available repositories. In order to provide better coverage of abbreviations, and also to address the issue of neologisms in general, word embeddings were applied to find semantically similar lexemes.
- PublicationABI: A mechanism for increasing video delivery quality in multi-radio Wireless Mesh Networks with Energy SavingWireless Mesh Networks (WMNs) are becoming increasingly popular mostly due to their ease of deployment. One of the main drawbacks of these networks is that they suffer with respect to Quality of Service (QoS) provisioning to its clients. Equipping wireless mesh nodes with multiple radios for increasing the available bandwidth has become a common practice nowadays due to the low cost of the wireless chipsets. Even though the available bandwidth increases with each radio deployed on the mesh node, the energy consumed for transmission increases accordingly. Thus, efficient usage of the radio interfaces is a key aspect for keeping the energy consumption at low levels while keeping a high QoS level for the mesh network’s clients. In the light of the above presented aspects concerning WMNs, the contribution of this paper is two-fold: (i) ABI, a mechanism for efficient usage of the available bandwidth for the mesh nodes, and (ii) decreasing the energy consumption by activating the radios only when needed. The solution proposed is throughly evaluated and shows that the two contributions can provide good QoS and decrease the overall energy consumption.
236Scopus© Citations 3