| 1. |
- Aamir, Syed Ahmed, 1980-, et al.
(författare)
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A 1.2-V pseudo-differential OTA with common-mode feedforward in 65-nm CMOS
- 2010
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Ingår i: Proceedings of the 17th IEEE International Conference on Electronics, Circuits, and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 29-32
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Konferensbidrag (refereegranskat)abstract
- In this work, we describe the implementation of a 1. 2-V pseudo-differential operational transconductance amplifier (OTA) with common-mode feedforward (CMFF) and inherent common-mode feedback (CMFB) in a 65-nm, digital CMOS process. The OTA architecture provides an inherent CMFB when cascaded OTA structures are utilized andthis work has studied a cascaded amplifier consisting of fourstages. Due to the low-gain using core 65-nm circuit devices, the overall gain must be distributed on all four stages to acquire a gain of more than 60 dB, while maintaining a-3-dB bandwidth of 200 MHz. To achieve high gain, we propose using a modified, positive-feedback, cross-coupled input differential stage. The modified OTA achieves a high output swing of ± 0.85 V due to only two stacked transistors, 88 dB DC gain and a third-order harmonic of -60 dB for 800 mVpp at 30 MHz. Further on, in a capacitive buffer configuration, we achieve a high slew rate of 1240 V/µS, -3-dB bandwidth of 509 MHz, signal-to-noise ratio of 63 dB while consuming 10.4 mW power.
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| 2. |
- Aamir, Syed Ahmed, 1980-, et al.
(författare)
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A 500-MHz low-voltage programmable gain amplifier for HD video in 65-nm CMOS
- 2010
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Ingår i: Proceedings of 28th IEEE Norchip Conference., NORCHIP'10. - Tampere : www.ieee.org. - 9781424489718 - 9781424489725 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- This work describes the implementation of a 1.2-V programmable gain amplifier (PGA) for high-definition (HD) video digitizers in a 65-nm digital CMOS process. The “pseudo” switched-capacitor (SC) PGA architecture buffers the video signal, without switching, during the active video. The SC circuitry is used for setup of DC operating point during horizontal and vertical blanking periods. Additionally, it compensates for the `sync-tip' of analog video signals to an equal blanking level for increased dynamic range to the digitizer following the PGA. The operational transconductance amplifier (OTA) employed as main amplifier in the PGA is a pseudo-differential, positive-feedback input stage architecture with a common-mode feedforward (CMFF) technique. The common-mode feedback (CMFB) is provided once two OTAs are cascaded. Schematic-level simulation results show that the OTA maintains a -3-dB bandwidth of 550 MHz, while keeping the distortion HD3 at -60 dB for a 30-MHz, 850 mVpp high definition video signal. The 88 dB DC gain is distributed among four OTA stages and the overall, combined PGA achieves a signal-to-noise ratio of 63 dB. Due to only two stacked transistors, it achieves high output swing of ±0.85 V, 1240 V/μs slew rate while consuming 10.4 mW power.
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| 3. |
- Abbas, Muhammad, et al.
(författare)
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Computational and Implementation Complexity of Polynomial Evaluation Schemes
- 2011
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Ingår i: Proceedings of NORCHIP, 2011 Date:14-15 Nov. 2011. - : IEEE conference proceedings. - 9781457705151 - 9781457705144 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- In this work, we consider the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained. These can then be used to short list suitable candidates for an implementation given the specifications. Not only multiplications are considered, but they are divided into data-data multiplications, squarers, and data-coefficient multiplications, as the latter can be optimized depending on implementation architecture and application.
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| 4. |
- Abbas, Muhammad, et al.
(författare)
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Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy
- 2010
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Ingår i: Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010. - Washington, DC, USA : IEEE Computer Society. - 9781424497225 ; , s. 1168-1172
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Konferensbidrag (refereegranskat)abstract
- In this work, we investigate the problem of computing any requested set of power terms in parallel using summations trees. This problem occurs in applications like polynomial approximation, Farrow filters (polynomial evaluation part) etc. In the proposed technique, the partial product of each power term is initially computed independently. A redundancy check is then made in each and among all partial products matrices at bit level. The redundancy here relates to the fact that same three partial products may be present in more than one columns, and, hence, can be mapped to the same full adder. The proposed algorithm is tested for different sets of powers and wordlengths to exploit the sharing potential.
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| 5. |
- Abbas, Muhammad, et al.
(författare)
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Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology
- 2010
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Ingår i: Proceedings of International Conference on Green Circuits and Systems (ICGCS), 2010, Date: 21-23 June, 2010. - : IEEE. - 9781424468775 - 9781424468768 ; , s. 221-225
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Konferensbidrag (refereegranskat)abstract
- The power modeling of different realizations of cascaded integrator-comb (CIC) decimation filters has been a subject of several recent works. In this work we have extended these with modeling of leakage power, which is an important factor since the input sample rate may differ several orders of magnitude. Furthermore, we have pointed out the importance of the input wordlength on the comparison of recursive and nonrecursive implementations.
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| 6. |
- Abbas, Muhammad, et al.
(författare)
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Switching Activity Estimation of CIC Filter Integrators
- 2010
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Ingår i: Proceedings of Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), 2010, Date:22-24 Sept. 2010. - : IEEE. - 9781424467365 - 9781424467358 ; , s. 21-24
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Konferensbidrag (refereegranskat)abstract
- In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters.
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| 7. |
- Abbas, Qaisar, et al.
(författare)
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Energy Stability of the MUSCL Scheme
- 2010
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Ingår i: Proc. 7th South African Conference on Computational and Applied Mechanics. - Berlin : South African Association for Theoretical and Applied Mechanics. ; , s. 65:1-8, s. 61-68
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Abbott, Allan, et al.
(författare)
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Early rehabilitation targeting cognition, behaviour and motor function after lumbar fusion: A randomised controlled trial
- 2010
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Ingår i: Abstracts. ; , s. 186-186
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Study Design: Open label randomised controlled trial with 3, 6, 12 month and 2-3 year follow-up.Objective. To investigate the effectiveness of a psychomotor therapy focusing on cognition, behaviour and motor relearning compared to exercise therapy applied during the first 3 months after lumbar fusion.Methods: The study recruited 107 patients, aged 18 to 65 years, selected for lumbar fusion due to 12 months of symptomatic spinal stenosis, degenerative/isthmic spondylolisthesis or degenerative disc disease. The exercise therapy group received a home program focusing on pain contingent training of back, abdominal and leg muscle functional strength and endurance, stretching and cardiovascular fitness. The psychomotor therapy group received a home program and 3 outpatient sessions focusing on modifying maladaptive pain cognitions, behaviours and motor control. Patient-rated questionnaires investigating functional disability, pain, health related quality of life, functional self-efficacy, outcome expectancy, fear of movement/(re)injury and copingwere assessed at baseline, 3, 6, 12 months and 2-3 years after surgery.Results: Follow-up rates were 93% at 12 months and 81% at 2-3 years after surgery. Psychomotor therapy improved functional disability, self-efficacy, outcome expectancy and fear of movement/(re)injury significantly more than exercise therapy at respective follow-up occasions. Similar results occurred for pain coping but group differences were non-significant at 2-3 year follow-up.Conclusions: The study shows that post-operative rehabilitation can be effectively implemented during the first 3 months after lumbar fusion and should include measures to modify psychological aswell as motor functions.
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| 9. |
- Abbott, Allan, et al.
(författare)
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Multidimensional assessment of pain related disability after surgery for cervical disc disease
- 2013
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Ingår i: APA Conference 2013. - : Australian Physiotherapy Association. ; , s. 2-2
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Questions: Given only 25% of patients, 10 year post-surgery for cervical disc disease report clinically meaningful improvements in functional disability, what are the biopsychosocial factors associated with continued long-term disability? What are the implications for physiotherapy practice?Design: Cross-sectional observational study.Participants: Ninety patients who had undergone anterior discectomy and fusion (ACDF) surgery 10-13 years prior.Outcome Measures: The Neck Disability Index (NDI), ACDF surgery type, surgical fusion status, patient age and Part 1 of the West Haven-Yale multidimensional pain inventory Swedish version (MPI-S) were entered into a statistical model. Part 1 of the MPI-S contains 5 subscales: pain severity, interference, life control, affective distress and support.Results: Seventy-three patients answered the questionnaires. Non-linear categorical regression modeling (CATREG) of the selected predictive variables explained 76.1% of the variance in NDI outcomes 10-13 years post ACDF. Of these predictors, MPI-S affective distress subscale (β = 0.635, p = <0.001) and pain severity subscale (β = 0.354, p = <0.001) were significant individual predictors of NDI ratings.Conclusion: This is the first study to investigate potential factors associated with prolonged functional disability greater than 10 years post-surgery for cervical disc disease. The results suggest the importance of not only pain severity but also screening affective distress as a potential barrier to physical functioning in patients previously operated for cervical disc disease. Future research on the utility of affect-focused body awareness therapy and pain coping strategies for post-surgical patients with continuing pain and physical disability is indicated.Key Practice Points:• The screening of pain severity and affective distress is of importance for patients presenting with continuing physical disability after previous surgery for cervical disc disorders• Affect-focused body awareness therapies and pain coping strategies may be a potential treatment alternative for patients with continuing pain and physical disability.
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| 10. |
- Abbott, Allan, et al.
(författare)
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The effectiveness of physiotherapeutic rehabilitation and issues of outcome prediction after lumber fusion surgery.
- 2011
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Ingår i: Proceedings of the WCPT Congress, Amsterdam Netherlands.. - : World Confederation of Physical Therapy. ; , s. 20-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: The primary purpose was to analyse the short and long term effectiveness of physiotherapeutic rehabilitation programs performed during the first 3 month after lumbar fusion surgery. A secondary purpose was to analyse factors predicting long-term disability, back pain and health related quality of life (HRQOL) outcomes after lumbar fusion.Relevance: The study provides evidence for the effectiveness of early physiotherapy after lumbar fusion. Furthermore improved knowledge of predictive factors can help physiotherapist in the screening of lumbar fusion candidates and the individualised implementation of pre-surgical and post-surgical interventions.Participants: A total of 107 patients were recruited from the Karolinska University Hospital's Orthopaedic Clinic, Stockholm, Sweden. The inclusion criteria were: men and women aged between 18 and 65 years with a >12 month history of back pain and/or sciatica; a primary diagnosis of spinal stenosis, degenerative or isthmic spondylolisthesis or degenerative disc disease; selected for lumbar fusion with or without decompression; competence in the Swedish language. The criteria for exclusion were: previous lumbar fusion, rheumatoid arthritis and ankylosing spondylitis.Methods: An open book randomised controlled trial with pre-surgical and post-surgical measures at 3, 6, 12 and 24-36 months was performed to investigate the effectiveness of a psychomotor therapy focusing on cognition, behaviour and motor relearning compared to exercise therapy focusing on strength and conditioning, applied during the first 3 months after lumbar fusion. Randomisation allocated 53 patients to psychomotor therapy and 54 patients to exercise therapy. The Oswestry disability index (ODI) was the primary outcome measure. Secondary measures included the Visual analogue scale for back pain (VAS), European quality of life questionnaire (EQ5D), as well as other clinical, psychological and work related variables.Analysis: A total of 78 patients were needed assuming a power = 80%. Patient compliance was analysed and an intention to treat principle applied to data analysis. For statistical comparison between the 2 independent groups, analysis of covariance was used. Categorical regression with optimal scaling transformation, elastic net regularization and bootstrapping were used to investigate pre-surgical predictor variables and address predictive model validity.Results: Follow-up rates were 93% at 12 months and 81% at 24-36 months after surgery. Psychomotor therapy improved functional disability, self-efficacy, outcome expectancy and fear of movement/(re)injury significantly more than exercise therapy at respective follow-up occasions. Pre-surgical control over pain significantly predicted functional disability and HRQOL. Pre-surgical catastrophizing and leg pain intensity significantly predicted functional disability and back pain while the pre-surgical lasegue test significantly predicted back pain. The implementation of post-operative psychomotor therapy also significantly predicted functional disability while pre-surgical outcome expectations significantly predicted HRQOL.Conclusions: The study shows that post-operative rehabilitation can be safely implemented during the first 3 months after lumbar fusion and should include measures to modify psychological as well as motor functions. The study also demonstrates the importance of pre-surgical psychological factors, leg pain intensity, the lasegue test and post-operative psychomotor therapy in the predictions of functional disability, back pain and HRQOL related outcomes.Implications: Physiotherapist should screen patients pain, psychological factors and neuromusculoskeletal system pre-surgically and rehabilitate patients with early psychomotor therapy after lumbar fusion.
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