A. H. Khalil

A 2.7 GHz super-regenerative receiver front-end for QPSK modulated signals

In this paper, the operation of super-regenerative (SR) receivers based on super-regenerative oscillators (SRO) is extended to enable the detection of QPSK modulated signals rather than traditional implementation of SR receivers to detect OOK signals. The ability of super-regenerative receivers to properly detect QPSK modulated signals enables using the benefits of such receivers of high gain and low power for current mainstream receivers for wireless sensor networks applications. For this purpose, a low power super-regenerative front end is proposed, it is composed of an LNA and (SRO) merged for current-reuse and operating at 2.7 GHz. The front-end embedded in a downconversion receiver demonstrates that SRO phase preserving property enables proper detection of QPSK modulated signal while consuming an average power of 0.54 mW from a 0.65 V supply at a bit rate of 4 Mbps equivalent to 135 pj/bit.

Testing of one stage Pipelined Analog to Digital Converter

Analog to Digital converters are some of the most commonly used mixed-signal circuits nowadays. Testing such circuits has recently become extremely important. In this paper, a low-cost test is developed for a one-stage Pipelined Analog-to-Digital Converter (PADC). This circuit consists of one operational amplifier, one comparator, five transmission gates and two capacitors and is based on a 90 nm CMOS technology. By applying simple DC test inputs, it is shown that only two DC test values are enough to detect all catastrophic faults in the fault set. The Eldo simulator provided by Mentor Graphics was used in the analysis.

Sampling optimization for macro-modeling interconnect parasitic extraction

Parasitic extraction is a critical task for modern nano scale semiconductor circuits which are characterized by high speed, small feature size and dense layout. Among the available extraction methodologies is the macro-modeling, which is based on dividing the circuit into smaller parts, then matching those smaller parts to a pre-defined model library whose parasitics are known. In the macro-modeling method, building the predefined model library goes into a number of stages; a major stage of them is the sampling stage, where we calculate the parasitic associated with the predefined models at a set of selected geometries (samples). Those samples are, then, used to build the model library by fitting them to a model equation. In this paper we are focusing on optimizing the sampling stage of the macro-modeling method for interconnect parasitic extraction. Herein, we optimize (minimize) the sample size where a graphically inspired method is introduced to define the minimum sample size for complex non-linear model equation mathematically. This method also addresses the impact of the data set uncertainty on the minimum required sample size. Then, we introduce a method for optimizing the distributing of those minimum required sample size. This sample distribution method, is based on Latin hypercube hybridization, optimizes inter-sample distances and correlations concurrently.

Design of ADPLL for good phase and frequency tracking performance

This paper describe a new all-digital phase-locked loop (ADPLL). We reconfigure the commercially available ADPLL 74HC297 with a newly developed digitally controlled oscillator (DCO) to obtain digitally a phase-frequency detector (PFD) which achieves good phase and frequency error detection performance not implemented in 74HC297. A complete VHDL RTL level design is developed and fully synthesized for both 74HC297 and the proposed ADPLL. The VHDL code is targeted to FPGA technology (Altera, Xilinx) and standard cell ASIC (Alcatel 0.5 micron technology). Simulation of the proposed ADPLL and 74HC297 shows good tracking and homogeneous output of the proposed ADPLL.

Design and implementation of a TV ghost cancelling system using high level synthesis tools

We introduce a system for TV ghost cancelling. A complete VHDL RTL level design had been developed and fully synthesized for the developed digital-processing chip. A complete behavioral model had been developed and visual simulation had been done using Matlab. The assistant TV interface system had been designed using available off the shelf components that can be integrated in our design. The VHDL code has been targeted for FPGA technology (Altera Xilinx) and standard cell ASIC (Alcatel 0.5 micron technology).

Interconnects Parasitic Extraction using natural optimization techniques

Three new Genetic Algorithm (GA) approaches and four new Particle Swarm Optimization (PSO) approaches are proposed and used to solve a Curve fitting problem for Parasitic Extraction Macro-modeling application. For GA, the first proposed approach, Diagonal GA (DGA); is based on replacing the traditional random population initialization method with a deterministic diagonal-like one. The second proposed approach, Elite Condensation GA (ECGA); is based on fine-tuning the GA by explicitly condensing the population around a number of elite individuals. The third proposed approach, ECGA2, is a modified version of ECGA; that chooses elite members among all the population in each generation, then it divides the population into a number of sub-populations where each sub-population is composed of a single elite and a condensed population around it. Then, it performs GA operations on each of those sub-populations separately before merging them all into one population and keep repeating that divide-merging sequence. For PSO, in the first proposed approach, Wiggling PSO (WPSO); we enforce the particles to vibrate in their motion towards the best position -instead of straight motion- to enlarge the scanning area. The second approach, Incrementally Social PSO (ISPSO); is utilizing a variable weight for the social term (xg-x). This variability enables changing the social relationship between the particles from highly repulsive to highly attractive. Finally, we proposed a new Control inspired approach, PID-PSO, where we dealt with the PSO motion as a process that needs a controller to be optimized. It is quite common to use PSO to tune PID parameters but in this context we used PID to tune PSO motion. Eventually, we have mixed PID and ISPSO in a certain proposal which resulted in the best performance over the rest of methods. The performances of these seven proposed approaches were measured on an extensive real data sets provided by Mentor Graphics and used along with the understanding of the physical problem to offer various explanations of the theoretical aspects of the new extensions.

Novel technique for reducing effects of non-linear frequency sweeps in LFM ranging radars

A new technique for overcoming VCO (Voltage Controlled Oscillator) non-linearity in FMCW (Frequency Modulated Continuous Wave) radar transceivers is presented. The proposed technique relies on correlating the output beat signal in the stretch processing technique with a pre-formed reference correlation signal that accounts for the VCO non-linearity. An overview of the FMCW radar is presented followed by a discussion of the VCO non-linearity problem with existing solutions. The proposed solution is demonstrated with supporting simulation results. The benefits of the proposed solution are stated with a suggestion of a possible simple realization.

Living donor liver transplantation for hepatocellular carcinoma: Milan criteria versus University of California San Francisco

Introduction Hepatocellular carcinoma (HCC) is the most common primary liver cancer and most patients with HCC also suffer from coexisting cirrhosis. HCC recurrence is a major concern after liver transplant. The Milan criteria was accepted after a good 5 years survival but was criticized for being so restricted and this criticism promoted the appearance of more expanded criteria like the University of California San Francisco (UCSF). Our study compares the results of both Milan and UCSF criteria and the risk factors for recurrence. Patients and methods This study included 60 patients had living donor liver transplantation for HCC between January 2011 and December 2016 in Ain Shams Center for Organ Transplantation.They were divided into two groups. Group A: transplanted within the Milan criteria; and group B: transplanted while beyond Milan but within the UCSF criteria. Both groups are compared as regards the recurrence, survival, and risk factors for recurrence. Results There is no statistically significant difference between the two groups as regards the survival and recurrence. The 1 and 3 years survival were 86.5 and 71.9% for the Milan group and 81.7 and 61.4% in the group of patients beyond Milan (statistically nonsignificant, P=0.348). Seven (15.1%) patients from the Milan group had recurrence while in the beyond Milan group four (28.6%) patients had recurrence (statistically nonsignificant, P=0.258). There were no statistically significant difference in microvascular invasion (P=0.388), tumor grade (P=0.207), and α-fetoprotein (P=0.112) between both groups. Conclusion Milan criteria can be safely expanded to UCSF with comparable results if responding well to downstaging and with low α-fetoprotein.

Resection of hepatocellular carcinoma in cirrhotic patients: laparoscopic versus open resection

Background Liver resection is an established modality of treatment for hepatocellular carcinoma although not commonly used in liver cirrhosis due to the poor liver reserve and the risk of decompensation. Laparoscopic surgery is known for its short-term and long-term benefits. Also, laparoscopic hepatectomy has many advantages in cirrhotic patients like minimizing the destruction of collateral blood and lymphatics. Our study aims at evaluating the effectiveness and safety of laparoscopic approach in patients with cirrhotic livers and compares it with the open approach. Patients and methods This prospective study involved 65 patients with hepatic tumors (with Child A classification) managed by hepatic resection at Ain Shams University Hospitals (Ain Shams University) and Badr Hospital (Helwan University) during the period from October 2014 to August 2016. The patients were randomly divided into two groups, group A (32 patients) was managed with laparoscopic hepatic resection technique and group B (33 patients) was managed with open hepatic resection technique. The patients were followed up to 12 months from the time of operation. Results Group A showed significantly shorter hospital stay; the mean hospital stay in the open group was 5.51±1.28 days ranging from 4 to 7 days, while in the laparoscopic group it was 3.75±1.16 days ranging from 3 to 5 days with highly statistically positive correlation difference between the two groups (P<0.001). Also, postoperative complications (mainly postoperative ascites) were significantly lower in the laparoscopic group, with no statistically significant difference in 1-year survival or recurrence rate. Conclusion The laparoscopic approach has superior short-term outcome compared with the open approach. Laparoscopic approach carries less postoperative complications and should be considered when possible.

How far is sleeve gastrectomy more effective than diet regimen in treating obesity-associated hyperlipidemia

Background The global epidemic of obesity is one of the major health issues in the 21st century that influences many aspects of public health, including psychosocial and socioeconomic aspects. Hyperlipidemia is one of the health hazards associated with morbid obesity. Patients and methods This was a prospective study conducted in Kasr Al-Aini University Hospital (sleeve gastrectomy group) and the National Nutrition Institute (diet group) during the period from June 2015 till December 2015 with a follow-up of 12 months till December 2016 for both groups. One hundred patients were included in the study and were equally divided into two groups: group A (sleeve gastrectomy group) and group B (diet group). Objective The objective of this study was to compare the effects of laparoscopic sleeve gastrectomy (LSG) and a dietary regimen on hyperlipidemia in morbidly obese patients. Results LSG significantly decreased total cholesterol in 70% of cases and triglycerides in 78% of cases; however, diet caused a decrease of total cholesterol in 30% of cases and triglycerides in 54% of case. Low-density lipoprotein was not significantly changed in both groups. Conclusion LSG is more effective than diet programs in treating obesity-associated hyperlipidemia due to more significant and sustained excess body weight loss.