Neural Decoder for Topological Codes using Pseudo-Inverse of Parity Check Matrix

Recent developments in the field of deep learning have motivated many researchers to apply these methods to problems in quantum information. Torlai and Melko first proposed a decoder for surface codes based on neural networks. Since then, many other researchers have applied neural networks to study a variety of problems in the context of decoding. An important development in this regard was due to Varsamopoulos et al. who proposed a two-step decoder using neural networks. Subsequent work of Maskara et al. used the same concept for decoding for various noise models. We propose a similar two-step neural decoder using inverse parity-check matrix for topological color codes. We show that it outperforms the state-of-the-art performance of non-neural decoders for independent Pauli errors noise model on a 2D hexagonal color code. Our final decoder is independent of the noise model and achieves a threshold of $10 \%$. Our result is comparable to the recent work on neural decoder for quantum error correction by Maskara et al.. It appears that our decoder has significant advantages with respect to training cost and complexity of the network for higher lengths when compared to that of Maskara et al.. Our proposed method can also be extended to arbitrary dimension and other stabilizer codes.Comment: 12 pages, 12 figures, 2 tables, submitted to the 2019 IEEE International Symposium on Information Theor

Uric acid levels in chronic kidney disease- a hospital based cross-sectional study in RIMS, Ranchi, Jharkhand

Background: Uric acid is the final end product of purine metabolism and is excreted mainly by proximal tubules of the kidney. Raised uric acid levels may lead to proximal tubular injury, endothelial dysfunction, oxidative stress and intra renal inflammation in patients with normal renal function. Uric acid has been deemed as an independent risk factor for progression of CKD. Aim was to study the uric acid levels in different stages of chronic kidney disease and its association with age, sex and other co-morbidities.Methods: 140 patients of chronic kidney disease admitted in RIMS, Ranchi were included in this study and their serum uric acid level were analyzed. Uric acid level more than 7 mg/dl was considered as hyperuricemia. The study was approved by the Institutional Ethics Committee, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India. Informed consent was taken from every patient included in the study.Results: Median age±SD was 55±13.47 years (IQR: 45,65; Range: 19-80). Mean±SD uric acid levels in stage 3 CKD was 4.4±1.9 mg/dl, stage 4 CKD was 6.5±4.1 mg/dl, stage 5 CKD was 8.8±3.1 mg/dl (p<0.05). Females were 31.4% and males were 69.6%. Male to female ratio was 2.2:1. The prevalence of hyperuricemia was 50% in females and 66.6% in males.Conclusions: Hyperuricemia is common among CKD patients and more common among males. Uric acid levels increase with progressive decline in eGFR. Monitoring and follow-up of such patients by may lead to delay in onset and progression of complications of CKD

Handoffs in hierarchical macro/femto networks and an algorithm for efficient handoffs

The surest way to increase the system capacity of a wireless link is by getting the transmitter and receiver closer to each other, which creates the dual benefits of higher-quality links and more spatial reuse. In a network with nomadic users, this inevitably involves deploying more infrastructure, typically in the form of microcells, hot spots, distributed antennas, or relays. A less expensive alternative is the recent concept of femtocells also called home base stations which are data access points installed by home users to get better indoor voice and data coverage. In macro/femto hierarchical networks, one of the biggest challenges is ensuring efficient handoffs. Here in this thesis, we first evaluated received signal strength at mobile user using different path loss models (indoor and outdoor) which is the main criterion for performing handoff. We also obtained the interference and SINR scenarios for handoff performance. Then we derived some basic handoff parameters like handoff probability, radio link failure rate, ping-pong handoff for macro/femto environment. Finally we proposed an algorithm for efficient handoff. The main idea of the proposed algorithm is to combine the values of received signal strength from a serving macro BS and a target femto BS in the consideration of large asymmetry in their transmit powers. Numerical results show that there is a significant gain in view of the probability that the user will be assigned to the femtocell while keeping the same level of the number of handoffs

Density Matrix Embedding Using Multiconfiguration Pair-Density Functional Theory

We present a quantum embedding method for ground and excited states of extended systems that uses multiconfiguration pair-density functional theory (MC-PDFT) with densities provided by periodic density matrix embedding theory (pDMET). We compute local excitations in oxygen mono- and divacancies on a magnesium oxide (100) surface and find absolute deviations within 0.05 eV between pDMET using the MC-PDFT, denoted as pDME-PDFT, and the more expensive, nonembedded MC-PDFT approach. We further use pDME-PDFT to calculate local excitations in larger supercells for the monovacancy defect, for which the use of nonembedded MC-PDFT is prohibitively costly

Sonographic Features of an Adult Granulosa Cell Tumor of the Testis

AbstractA 25-year-old man presented with epididymoorchitis. Sonography revealed a 5 mm hypoechoic lesion with scattered foci of high level echoes and an area of calcification in the upper pole of the left testicle close to the hilum. Growth and pronounced neovascularity was demonstrated a subsequent scan. An orchidectomy was performed and histological studies revealed a granulosa cell tumour of the testicle. Testicular granulosa cell tumors are extremely rare. Comparing the previously published findings to our case, we suggest that common sonographic features of testicular granulosa cell tumors include a hypoechoegenic lesion with hyperechoic and calcified foci, sharply defined edge, and internal vascularity

Boosting XML Filtering with a Scalable FPGA-based Architecture

The growing amount of XML encoded data exchanged over the Internet increases the importance of XML based publish-subscribe (pub-sub) and content based routing systems. The input in such systems typically consists of a stream of XML documents and a set of user subscriptions expressed as XML queries. The pub-sub system then filters the published documents and passes them to the subscribers. Pub-sub systems are characterized by very high input ratios, therefore the processing time is critical. In this paper we propose a "pure hardware" based solution, which utilizes XPath query blocks on FPGA to solve the filtering problem. By utilizing the high throughput that an FPGA provides for parallel processing, our approach achieves drastically better throughput than the existing software or mixed (hardware/software) architectures. The XPath queries (subscriptions) are translated to regular expressions which are then mapped to FPGA devices. By introducing stacks within the FPGA we are able to express and process a wide range of path queries very efficiently, on a scalable environment. Moreover, the fact that the parser and the filter processing are performed on the same FPGA chip, eliminates expensive communication costs (that a multi-core system would need) thus enabling very fast and efficient pipelining. Our experimental evaluation reveals more than one order of magnitude improvement compared to traditional pub/sub systems.Comment: CIDR 200