Are Slepian-Wolf Rates Necessary for Distributed Parameter Estimation?

We consider a distributed parameter estimation problem, in which multiple terminals send messages related to their local observations using limited rates to a fusion center who will obtain an estimate of a parameter related to observations of all terminals. It is well known that if the transmission rates are in the Slepian-Wolf region, the fusion center can fully recover all observations and hence can construct an estimator having the same performance as that of the centralized case. One natural question is whether Slepian-Wolf rates are necessary to achieve the same estimation performance as that of the centralized case. In this paper, we show that the answer to this question is negative. We establish our result by explicitly constructing an asymptotically minimum variance unbiased estimator (MVUE) that has the same performance as that of the optimal estimator in the centralized case while requiring information rates less than the conditions required in the Slepian-Wolf rate region.Comment: Accepted in Allerton 201

Distributed Statistical Learning under Communication Constraints

In this thesis, we study distributed statistical learning, in which multiple terminals, connected by links with limited capacity, cooperate to perform a learning task. As the links connecting the terminals have limited capacity, the messages exchanged between the terminals have to be compressed. The goal of this thesis is to investigate how to compress the data observations at multiple terminals and how to use the compressed data for inference. We first focus on the distributed parameter estimation problem, in which terminals send messages related to their local observations using limited rates to a fusion center that will obtain an estimate of a parameter related to the observations of all terminals. It is well known that if the transmission rates are in the Slepian-Wolf region, the fusion center can fully recover all observations and hence can construct an estimator having the same performance as that of the centralized case. One natural question is whether Slepian-Wolf rates are necessary to achieve the same estimation performance as that of the centralized case. In this thesis, we show that the answer to this question is negative. We then examine the optimality of data dimensionality reduction via sufficient statistics compression in distributed parameter estimation problems. The data dimensionality reduction step is often needed especially if the data has a very high dimension and the communication rate is not as high as the one characterized above. We show that reducing the dimensionality by extracting sufficient statistics of the parameter to be estimated does not degrade the overall estimation performance in the presence of communication constraints. We further analyze the optimal estimation performance in the presence of communication constraints and we verify the derived bound using simulations. Finally, we study distributed optimization problems, for which we examine the randomized distributed coordinate descent algorithm with quantized updates. In the literature, the iteration complexity of the randomized distributed coordinate descent algorithm has been characterized under the assumption that machines can exchange updates with an infinite precision. We consider a practical scenario in which the messages exchange occurs over channels with finite capacity, and hence the updates have to be quantized. We derive sufficient conditions on the quantization error such that the algorithm with quantized update still converge

Conditional Decoding for X Channels

The conditional decoder is a low complexity and optimal decoder for multiplexed orthogonal designs in point-to-point channels. We extend this notion to X channels and differentiate between two interference scenarios. First, the interference is perfectly aligned in a different sub-space than the intended information symbols. For this scenario, the conditional decoder is applied as a one stage and two stages decoder to cancel the interference and decode the desired signal. Second, the interference is misaligned. In this case, the conditional decoder attempts to jointly cancel the interference and decode the intended signal while achieving a performance gain over other interference cancellation schemes. We consider the two user scenario where Alamouti codes are used at the transmitters and then extend our investigation to three user channels with arbitrary signal structure. Our numerical results establish the superiority of our decoder to previously proposed zero-forcing and decoupling techniques, in terms of performance. It is further shown that the proposed decoder achieves the same performance as the sphere decoder; while enjoying a much lower implementation complexity

Ultra-wideband CMOS power amplifier for wireless body area network applications: a review

A survey on ultra-wideband complementary metal-oxide semiconductor (CMOS) power amplifiers for wireless body area network (WBAN) applications is presented in this paper. Formidable growth in the CMOS integrated circuits technology enhances the development in biomedical manufacture. WBAN is a promising mechanism that collects essential data from wearable sensors connected to the network and transmitted it wirelessly to a central patient monitoring station. The ultra-wideband (UWB) technology exploits the frequency band from 3.1 to 10.6 GHz and provides no interference to other communication systems, low power consumption, low-radiated power, and high data rate. These features permit it to be compatible with medical applications. The demand target is to have one transceiver integrated circuit (IC) for WBAN applications, consequently, UWB is utilized to decrease the hardware complexity. The power amplifier (PA) is the common electronic device that employing in the UWB transmitter to boost the input power to the desired output power and then feed it to the antenna of the transmitter. The advance in the design and implementation of ultra-wideband CMOS power amplifiers enhances the performance of the UWB-transceivers for WBAN applications. A review of recently published CMOS PA designs is reported in this paper with comparison tables listing wideband power amplifiers' performance

Low cost detection of hepatitis C virus RNA in HCV infected patients by SYBR Green I real-time PCR

The prevalence of hepatitis C virus (HCV) is highest in Egypt compared to other countries. Nucleic acid amplification test (NAT) allows detection of HCV early during the course of infection. Unfortunately, NAT is more expensive than ELISA, thus its routine use as a screening tool for blood products or in clinical practice is quite limited. The aim of this study was to compare two common RT-PCR methods, TaqMan probe technique and SYBR Green method in quantitative detection of HCV RNA for diagnosis and follow up of HCV patients. Among the recruited 220 HCV patients, 154 (70%) were HCV-RNA positive by both the techniques, while 24 (10.9%) were negative by both techniques. On the other hand, 40 (18.2%) cases were HCV RNA positive only by SYBR Green technique, and 2 (0.9%) only by TaqMan probe technique. Forty (20.4%) of the 196 chronic HCV cases were HCV-RNA positive by SYBR Green but negative by TaqMan probe technique.Conclusion: This method is useful for rapid qualitative detection of HCV infection and particularly suitable for routine diagnostic applications.Keywords: HCV, PCR, SYBR Green 1, TaqMan probe, Viral loa

Surgical treatment of displaced intra-articular calcaneal fracture using a single small lateral approach

The objective of this study was to evaluate the outcome of semi-open reduction and minimal internal fixation through a single small lateral approach as a minimally invasive technique for treatment of displaced intra-articular calcaneal fractures. This prospective study was conducted on eighteen patients (16 men and 2 women). The average age was 37.7 (22–55). The most common cause of injury was a fall from height in fourteen patients. Patients were operated on within a mean time of 4.8 days of admission (1–11 days) and were followed up for an average period of 24.1 months (6–39 months). Patients were evaluated clinically using the Creighton-Nebraska Heath Foundation Assessment score of Crosby and Fitzgibbons (J Bone Joint Surg (Am) 72-A:852–859, 1990). The scoring system proposed by Knirk and Jupiter was used for radiological assessment of the posterior subtalar joint (Knirk and Jupiter in J Bone Joint Surg (Am) 68-A: 647–659, 1986). The skin incision healed in all cases without necrosis, infection, or sural nerve injury. All fractures healed after an average of 8 weeks (7–10 weeks), and patients returned to the routine daily activities after an average time of 4.3 months (3–7 months). In conclusion, semi-open reduction and minimal internal fixation through a small lateral approach is an effective treatment for carefully selected cases of displaced intra-articular calcaneal fractures

Implementation of a bowel management program in the treatment of incontinence in children for primary healthcare providers

Objectives: Our surgical team has devised a bowel management program (BMP) as a basic approach for primary healthcare providers with the least use of resources.Background: Soiling in children is a major problem that has a serious impact on the child’s social and psychological life. Causes vary from idiopathic constipation to postoperative or neuropathic causes as meningomyelocele.Participants and methods: Seventy five children suffering from fecal incontinence were assessed and divided into true incontinence and pseudoincontinence groups. The BMP was applied to both categories in the form of proper diet control, enemas, drugs, and bowel habit alteration. The program was fashioned according to the age, type, severity, and response of each case. A fecal incontinence scoring system was used to assess the results.Results: All cases with pseudoincontinence attained 50% or more improvement in incontinence score whereas the true incontinence cases attained excellent results except in post high anorectal malformation repairs and neurologic groups.Conclusion: Most of the cases suffering from constipation with pseudoincontinence can be treated properly by BMPs, whereas the minority suffering from true incontinence need multidisciplinary work to achieve acceptable results.Keywords: anorectal malformations, bowel management program, chronic idiopathic constipation, fecal incontinence, Hirschsprung’s disea

Impact of a Designed Nursing Intervention Protocol about Preoperative Liver transplantation Care on Patients’ Outcomes at A University Hospital in Egypt

Background: Literature review cited that, Liver transplantation is now considered as the gold standard for treatment of patients with end-stage liver diseases and early liver tumors in cirrhotic livers. Patient education is vital to the safety and success of a transplant. Aim: the aim is to assess the impact of a designed nursing intervention protocol about preoperative liver transplantation care on patient’s outcomes as indicated by: patients` knowledge & practice mean scores, and complications developed. To fulfill the aim of this study, the following hypothesis was formulated: patients undergoing liver transplantation who will be exposed to the designed nursing intervention protocol about preoperative liver transplantation care will show better outcomes. Material and Methods: A convenient sample of 14 adult male and female patients admitted to Liver Transplant Unit at El Manial University Hospital were included, three of them were died with an attrition rate of 21.4%. Four tools were formulated to collect data pertinent to the study. 1- Sociodemographic and medical data sheet; 2- Pre/Post knowledge assessment questionnaire sheet, 3- Observational checklists, & 4- Complications assessment sheet. Structured interview, reviewing medical records, direct observation and physical examination were utilized for data collection. Results: a  significant statistical difference was found in relation to the total and subtotal mean knowledge and practice scores during different assessment periods  with P values (0.00 for both); as well, 45.5 %  of patients developed respiratory complications (pleural effusion) compared to 53.8 % of their correspondence who developed respiratory complications (pleural effusion, chest infection, and others), in addition, 9.1% of the studied subjects developed  rejection, and ascites as compared to (1.9 %, 5.7%) of their correspondence over the last consecutive three years respectively. Conclusion: Liver transplantation patients showed a positive improvement in their knowledge and practice in relation to breathing, coughing, & using respirometer exercises and range of motion. Replication of this study on a larger sample selected from different geographical areas is highly recommended. Key wards: liver transplantation, designed nursing intervention protocol, preoperative liver transplantation care, knowledge, complications, and patient`s outcome