Design Techniques for High-Performance SAR A/D Converters

The design of electronics needs to account for the non-ideal characteristics of the device technologies used to realize practical circuits. This is particularly important in mixed analog-digital design since the best device technologies are very different for digital compared to analog circuits. One solution for this problem is to use a calibration correction approach to remove the errors introduced by devices, but this adds complexity and power dissipation, as well as reducing operation speed, and so must be optimised. This thesis addresses such an approach to improve the performance of certain types of analog-to-digital converter (ADC) used in advanced telecommunications, where speed, accuracy and power dissipation currently limit applications. The thesis specifically focuses on the design of compensation circuits for use in successive approximation register (SAR) ADCs. ADCs are crucial building blocks in communication systems, in general, and for mobile networks, in particular. The recently launched fifth generation of mobile networks (5G) has required new ADC circuit techniques to meet the higher speed and lower power dissipation requirements for 5G technology. The SAR has become one of the most favoured architectures for designing high-performance ADCs, but the successive nature of the circuit operation makes it difficult to reach ∼GS/s sampling rates at reasonable power consumption. Here, two calibration techniques for high-performance SAR ADCs are presented. The first uses an on-chip stochastic-based mismatch calibration technique that is able to accurately compute and compensate for the mismatch of a capacitive DAC in a SAR ADC. The stochastic nature of the proposed calibration method enables determination of the mismatch of the CAPDAC with a resolution much better than that of the DAC. This allows the unit capacitor to scale down to as low as 280aF for a 9-bit DAC. Since the CAP-DAC causes a large part of the overall dynamic power consumption and directly determines both the sizes of the driving and sampling switches and the size of the input capacitive load of the ADC and the kT/C noise power, a small CAP-DAC helps the power efficiency. To validate the proposed calibration idea, a 10-bit asynchronous SAR ADC was fabricated in 28-nm CMOS. Measurement results show that the proposed stochastic calibration improves the ADC’s SFDR and SNDR by 14.9 dB, 11.5 dB, respectively. After calibration, the fabricated SAR ADC achieves an ENOB of 9.14 bit at a sampling rate of 85 MS/s, resulting in a Walden FoM of 10.9 fJ/c-s. The second calibration technique is a timing-skew calibration for a time-interleaved (TI) SAR ADC that calibrates/computes the inter-channel timing and offset mismatch simultaneously. Simulation results show the effectiveness of this calibration method. When used together, the proposed mismatch calibration technique and the timing-skew calibration technique enables a TI SAR ADC to be designed that can achieve a sampling rate of ∼GS/s with 10-bit resolution and a power consumption as low as ∼10mW; specifications that satisfy the requirements of 5G technology

A comparison of various influential points diagnostic methods and robust regression approaches: reanalysis of interstitial lung disease data

In a linear regression model, the estimation of regression parameters by ordinary least squares method is affected by some anomalous points in the data set. Thus, detection of these abnormal points is one of the essential steps in regression analysis. There are many classical single deletion diagnostic measures which may fail to detect strange points due to masking effect. Local influence is an alternative method to evaluate the influence of local departures from assumptions in a proposed model. The main objective of this paper is to obtain the best resistant regression method which is robust to outliers in both the response and the explanatory variables. To achieve this objective, the weight vectors of the most commonly used robust regression techniques, such as the M- and the Generalized M-regressions are studied. A new measure based on the normal curvatures of the likelihood displacement is also proposed for comparing different robust regression methods. A medical data set is reanalyzed to underline that the use of only one alternative detection method or robust regression approach may not be sufficient to detect all influential points or to conclude the best robust method. A Monte Carlo simulation study is performed to confirm the results

Investigating Effect of Development of Agricutural, Industrial, Service and Oil Revenue to ICOR ofAgricultural Sector

In this study, considering the importance of incremental capital output ratio (ICOR) in agriculture Investment capital and self-sufficiency in this sector in order to grow and being influenced by the past and previous relationships strong agricultural sector productivity growth in other sectors of the economy, especially the effect of oil revenues, was trying to, long-term relationships as well as their adjustment process described by the Autoregressive-Distributed Lag model (ARDL) to investigate.The results also confirm the long-run relationship between the variables of the model show that oil revenues in appropriate path to growth agricultural productivity have beentoo much attention to the industry and imports of agricultural products decreased investment in agricultural productivity. However, the service sector growth by improving marketing activities and financing farmers to improve venture capital productivity in the agricultural sector operates. In the long run, adjusting the intersection, the model indicates improved productivity in the agricultural sector is of capital. Shown the necessary support to the agricultural sector in the short term

An exploration study on factors influencing green marketing

These days, there have been tremendous efforts on offering products, which are environment friendly. Green marketing plays an important role for attracting new customer and customer retention. This paper presents an empirical investigation based on the implementation of factor analysis to locate important factors influencing green marketing planning and strategies. building market oriented business units. The study designs a questionnaire including 23 questions and the questionnaire was distributed among 200 people who were visiting organic product exhibition. Cronbach alpha was calculated as 0.845, which is well above the minimum acceptable limit and validates the results. The results of factor analysis reveal four major factors including green labeling, compatibility, product value and marketing component and size

Testing for Asset Pricing Model based on Sentiment Indexes: SAPM Model

The purpose of this article is to investigate the effect of behavioral deviations on the pricing of financial assets with the assumption that sentiment is an important and relevant risk factor in the Iranian capital market. This paper also examines the effect of sentiment, momentum, size, value, and market risk premium by estimating the Multi-Factor Asset Pricing Model (APT). In order to perform empirical analysis, the quarterly returns of companies listed on the Tehran Stock Exchange in the period 2010-2019 in the form of 18 stock exchange groups including 63 listed companies are used. Using two indicators of market turnover sentiment.  and sentiment effect. we estimate the sentiment index and by extending the Carhart model and considering two sentiment variables in the form of SAPM model, coefficients estimate by using Hausman-Taylor panel data method. The results of the model show that in the SAPM model, the sentiment variable is very important and significant and have a positive relationship with the average seasonal rate of return of different stock exchange groups

The effect of probiotics mixture on learning and spatial memory in kindled rats

Background: Repeated seizure attacks lead to extensive neuronal damage and cognitive impairment such as memory loss and learning. Probiotics are shown to have some protective actions against neurological disorders. The present study aimed to examine the effect of probiotics on learning, memory and the nitric oxide level in kindled rats. Materials and Methods: In this experimental study, 40 male rats were randomly divided into five groups: control, kindled with penthylenetetrazole (PTZ), kindled and valproic acid (VPA), kindled after probiotic treatment (probiotic + PTZ), and kindled before probiotic treatment (PTZ + probiotic). The animals were treated by a mixture of probiotics for 4 weeks. Chemical kindling was induced by intraperitoneal injection of PTZ (35 mg/kg) every 48 hours for 24 days. The learning and spatial memory were evaluated by the Morris water maze. The serum nitric oxide level was assessed by the Miranda method. Results: No significant difference was observed between the control and VPA groups in terms of memory, learning and serum levels of nitric oxide. Learning (P<0.001) and spatial memory (P<0.05) phenomena were improved in the probiotic supplemented groups compared to the PTZ group. Also, serum nitric oxide levels were reduced in the probiotic supplemented groups (P<0.05). Conclusion: Probiotic supplementation reduces the level of nitric oxide and improves the learning and memory process

Effects of repeated intravitreal bevacizumab administration on anterior segment parameters and limbal stem cells

Background: Macular edema (ME) is fluid accumulation in the macula caused by vascular leakage. Repeated intravitreal bevacizumab (IVB) injections are extensively used to treat ME of different origins, are well tolerated, and have few side effects. This study evaluated the effects of repeated IVB injections on the anterior segment parameters and limbal stem cells (LSCs) in eyes with ME. Methods: This before–after study involved patients with ME of different causes who underwent repeated IVB injections at the Imam Khomeini Ophthalmology Center in Kermanshah, Iran. Before and after repeated IVB injections, anterior segment parameters were measured using anterior segment optical coherence tomography, and the LSCs were assessed using impression cytology. Results: We enrolled 42 eyes of 42 patients with a mean (standard deviation [SD]) age of 59.6 (7.6) years, of whom 25 (59.5%) were men and 17 (40.5%) were women. The underlying diseases included diabetic ME in 30 eyes (71.4%), central (5 [11.9%]) or branch (3 [7.1%]) retinal vein occlusion, and choroidal neovascularization in 4 eyes (9.5%). The right eye was affected in 22 (52.4%) participants. The mean (SD) number of IVB injections was 4.3 (1.3). After repeated injections, the mean central corneal thickness (CCT) increased, whereas the mean anterior chamber angle (ACA) and anterior chamber depth (ACD) decreased (all P<0.001). Three patients developed LSC deficiency after repeated IVB injections for diabetic ME. Conclusions: We observed a significant increase in the mean CCT and a decrease in the mean ACA and ACD after repeated IVB injections in our series. Three patients developed LSC deficiency after repeated IVB injections for diabetic ME management. The observed effect on LSC may cast doubt on the safety of repeated IVB injections; however, this finding must be verified in multicenter clinical trials with longer follow-up periods and larger study samples

High order modeling of shocks and disturbances in compressible flows using WENO scheme

Two new higher order version of WENO schemes are introduces and problems are solved to investigate problems containing shocks and disturbances in compressible flow. The solver is capable of solving conservation laws using WENO scheme of up to 7th order. The scheme is a recently developed version of the WENO-η-z method with a modified Global Smoothness Indicator (GSI) of 12th order of accuracy, aimed to decrease numerical dissipation over critical points. The code is primarily investigated trough solving several 1D and 2D problems, including the Sod’s shock tub, Lax’s problem, the Shu-Osher problem, which some are presented here as verification. The 2-D shock-bobble interaction and Richtmyer-Meshkov instability are solved as problems including shocks and disturbances, in which proposed methods are compared with both original WENO- η-z and two similarly modified methodes from recent literature. In these problems, the introduced scheme shows lower dissipation in comparison with the original versions, while having more acceptable stability and symmetry against other modifien versions

The effects of aerobic, resistance, and combined exercises on the plasma irisin levels, HOMA-IR, and lipid profiles in women with metabolic syndrome: A randomized controlled trial

Background/objective Irisin is suggested to be an exercise beneficial effects mediator. This study aimed to examine the effects of the aerobic exercise (AE), resistance exercise (RE), and combined exercise (CE) on the plasma levels of irisin and some metabolic and anthropometric indices. Methods Sixty overweight women with metabolic syndrome were assigned equally into four groups: AE, RE, CE, and control. The study variables were measured before and 24 h after the intervention period. Results None of the study groups showed statistically significant changes in the serum irisin. However, muscle mass significantly increased in the RE and CE groups. Also, a significant decrease was observed in the body fat percentage in all groups. In addition, compared with the control group, the homeostatic model assessment of insulin resistance in the AE (p = 0.021), RE (p = 0.039), and in the CE (p = 0.003) groups reduced significantly. According to the analysis of indices’ changes, serum irisin was significantly correlated with the body fat percentage (r = 0.532) and HOMA-IR (r = 0.424). Conclusions The systematic exercise program for 8-weeks did not change circulating irisin and no statistically significant difference was observed between the exercise methods. Also, serum irisin seemed to be associated with the glycemic status, body fat and weight independent of exercise activity.publishedVersionUnit Licence Agreemen

Production, Quality Control and Pharmacokinetic Studies of 166Ho-EDTMP for Therapeutic Applications

166Ho-EDTMP is a major therapeutic agent which is widely used in bone palliation therapy. In this study, a 166Ho-EDTMP complex was prepared successfully using an in-house synthesized EDTMP ligand and 166HoCl3. Ho-166 chloride was obtained by thermal neutron irradiation (1 × 1013 ncm−2s−1) of natural Ho(NO3)3 samples (specific activity = 3–5 GBq/mg), dissolved in acidic media. The radiochemical purity of 166Ho-EDTMP was checked by ITLC (>99%) and stability studies in presence of human serum and final preparation were performed. The biodistribution of 166Ho-EDTMP and 166HoCl3 in wild-type rats was checked by scarification. SPECT imaging of 166Ho-EDTMP was also performed in wild-type rats. A comparative accumulation study for 166Ho-EDTMP and 166HoCl3 was performed for vital organs up to 48h. Significant bone accumulation (>70%) of the tracer in 48h was observed