44 research outputs found
Excited-state intramolecular proton transfer of 2-acetylindan-1,3-dione studied by ultrafast absorption and fluorescence spectroscopy
Get PDFWe employ transient absorption from the deep-UV to the visible region and fluorescence upconversion to investigate the photoinduced excited-state intramolecular proton-transfer dynamics in a biologically relevant drug molecule, 2-acetylindan- 1,3-dione. The molecule is a ß-diketone which in the electronic ground state exists as exocyclic enol with an intramolecular H-bond. Upon electronic excitation at 300 nm, the first excited state of the exocyclic enol is initially populated, followed by ultrafast proton transfer (±160 fs) to form the vibrationally hot endocyclic enol. Subsequently, solvent-induced vibrational relaxation takes place (±10 ps) followed by decay (±390 ps) to the corresponding ground state. © 2015 Author(s)1561sciescopu
Clock multiplication techniques for high-speed I/Os
Get PDFGeneration of a low-jitter, high-frequency clock from a low-frequency reference clock using classical analog phase-locked loops (PLLs) requires a large loop filter capacitor and power hungry oscillator. Digital PLLs can help reduce area but their jitter performance is severely degraded by quantization error. In this dissertation different clock multiplication techniques have been explored that can be suitable for high-speed wireline systems. With the emphasis on ring oscillator based architecture using cascaded stages, three possible architectures are explored.
First, a scrambling TDC (STDC) is presented to improve deterministic jitter (DJ) performance when used with a low-frequency reference clock. A cascaded architecture with digital multiplying delay locked loop as the first stage and hybrid analog/digital PLL as the second stage is used to achieve low random jitter in a power efficient manner. Fabricated in a 90nm CMOS process, the prototype frequency synthesizer consumes 4.76mW power from a 1.0V supply and generates 160MHz and 2.56 GHz output clocks from a 1.25MHz crystal reference frequency. The long-term absolute jitter of the 60MHz digital MDLL and 2.56 GHz digital PLL outputs are 2.4 psrms and 4.18 psrms, while the peak-to-peak jitter is 22.1 ps and 35.2 ps, respectively. The proposed frequency synthesizer occupies an active die area of 0.16mm2 and achieves power efficiency of 1.86 mW/GHz.
Second, a hybrid phase/current-mode phase interpolator (HPC-PI) is presented to improve phase noise performance of ring oscillator-based fractional-N PLLs. The proposed HPC-PI alleviates the bandwidth trade-off between VCO phase noise suppression and ΔΣ quantization noise suppression. By combining the phase detection and interpolation functions into an XOR phase detector/interpolator (XOR PD-PI) block, accurate quantization error cancellation is achieved without using calibration. Use of a digital MDLL in front of the fractional-N PLL helps in alleviating the bandwidth limitation due to reference frequency and enables bandwidth extension even further. The extended bandwidth helps in suppressing the ring-VCO phase noise and lowering the in-band noise floor. Fabricated in 65nm CMOS process, the prototype generates fractional frequencies from 4.25 to 4.75 GHz, with an in-band phase noise floor of -104 dBc/Hz and 1.5 psrms integrated jitter. The clock multiplier achieves power efficiency of 2.4mW/GHz and FoM of -225.8 dB.
Finally, an efficient clock generation, recovery, and distribution techniques for flexible-rate transceivers are presented. Using a fixed-frequency low-jitter clock provided by an integer-N PLL, fractional frequencies are generated/recovered locally using multi-phase fractional clock multipliers. Fabricated in a 65nm CMOS, the prototype transceiver can be programmed to operate at any rate from 3-to-10 Gb/s. At 10 Gb/s, integrated jitter of the Tx output and recovered clock is 360 fsrms and 758 fsrms, respectively.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01The student, Romesh Kumar Nandwana, accepted the attached license on 2017-04-17 at 15:09.The student, Romesh Kumar Nandwana, submitted this Dissertation for approval on 2017-04-17 at 15:42.This Dissertation was approved for publication on 2017-04-19 at 08:46.DSpace SAF Submission Ingestion Package generated from Vireo submission #10816 on 2017-08-10 at 15:05:48Made available in DSpace on 2017-08-10T20:32:59Z (GMT). No. of bitstreams: 3
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Previous issue date: 2017-04-19Embargo set by: Colleen Fallaw for item 102771
Lift date: 2019-08-10T21:27:21Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 102771 on 2019-08-11T09:15:10Z
Anomaly-Based DNN Model for Intrusion Detection in IoT and Model Explanation: Explainable Artificial Intelligence
No full textIoT has gained immense popularity recently with advancements in technologies and big data. IoT network is dynamically increasing with the addition of devices, and the big data is generated within the network, making the network vulnerable to attacks. Thus, network security is essential, and an intrusion detection system is needed. In this paper, we proposed a deep learning-based model for detecting intrusions or attacks in IoT networks. We constructed a DNN model, applied a filter method for feature reduction, and tuned the model with different parameters. We also compared the performance of DNN with other machine learning techniques in terms of accuracy, and the proposed DNN model with weight decay of 0.0001 and dropout rate of 0.01 achieved an accuracy of 0.993, and the reduced loss on the NSL-KDD dataset having five classes. DL models are a black box and hard to understand, so we explained the model predictions using LIME.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
The impact of social isolation due to the COVID-19 pandemic on patients with dementia and caregivers
Get PDFSupplementary Material: To view supplementary material for this article, please visit https://doi.org/10.1017/neu.2022.12.Copyright © The Author(s) and Scandinavian College of Neuropsychopharmacology 2022. Objective:
Social distancing to limit COVID-19 transmission has led to extensive lifestyle changes, including for people with dementia (PWD). The aim of this study, therefore, was to assess the impact of lockdown on the mental health of PWD and their carers.
Methods:
Forty-five carers of PWD completed a telephone interview during the baseline assessment of the SOLITUDE study to gather information on life conditions and changes in symptoms of PWD during lockdown. Associations between changes in symptoms of PWD and carers’ concerns and mental health were investigated.
Results:
About 44% of carers experienced anxiety and irritability and reported changes in behavioural and cognitive symptoms in PWD. These changes were associated with worse carers’ mental health and concerns about faster disease progression (χ2 = 13.542, p < 0.001).
Conclusion:
COVID-19-related social isolation has had a negative impact on patients’ and carers’ mental health. Potential long-term neurocognitive consequences require further investigation.This research received no specific grant from any funding agency, commercial or not-for-profit sectors
Experimental investigations on Carbon-Nomex T410 reinforced polymer matrix composite for enhanced mechanical and tribological properties
No full textInvestigation of mechanical properties of aluminium reinforced glass fibre polymer composites
No full textDr. B.R. Ambedkar\u27s Vision of Indian Polity: Equality, Justice, and Social Transformation
Get PDFDr. B. R. Ambedkar, a well-known social activist as well as distinguished philosopher, was genuinely worried regarding the situation of the marginalised at the start of his distinguished career. He spent his whole life working to improve social and economic circumstances. Ambedkar\u27s transformative vision directs individual\u27s efforts as assists with renegotiating issues, particularly the collapse of modern political thought. Ambedkar became well-known as a key strategic philosopher throughout today\u27s society following the rise of the dalit struggle. He rose to prominence in India\u27s sociopolitical environment during the 1920s. With terms of political, economic, social or religious views, he was crucial to the improvement of the least rung of so-called indestructible Indian community. Furthermore, he was a brilliant sociologist, economist, judicial analyst, educationist, author, legislator, advocate, or rights-based activist. He was an iconoclast as well as researcher who successfullly organised, emancipated, or united the uneducated Indians opposing all forms of societal and political tyranny. This investigation captures Ambedkar\u27s views on politics
Theoretical analysis of the Fresnel lens as a function of design parameters
No full textThe author has studied the theoretical performance of the Fresnel lens as a function of the design parameters--i.e. the radius to the centre of the steps, the focal distance from the back of the lens to the plane of the image with the object (i.e. the sun) at infinity, the thickness of the lens plate, the step width and the refractive index of the material (with respect to air)--used in its fabrication. Numerical calculations have also been carried out for a Fresnel lens of perspex sheet.
