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Intrinsically random hardware devices are increasingly attracting attention for their potential use in probabilistic computing architectures. One such device is the single-photon avalanche diode (SPAD) and an associated functional unit, the variable-rate SPAD circuit (VRSC), recently proposed by us as a source of randomness for sampling and annealing Ising and Potts models. This work develops a more advanced understanding of these VRSCs by introducing several VRSC design options and studying their tradeoffs as implemented in a 65-nm CMOS process. Each VRSC is composed of a SPAD and a processing circuit. Combinations of three different SPAD designs and three different types of processing circuits were evaluated on several metrics such as area, speed, and variability. Measured results from the SPAD design space show that even extremely small SPADs are suitable for probabilistic computing purposes, and that high dark count rates are not detrimental either, so SPADs for probabilistic computing are actually easier to integrate in standard CMOS processes. Results from the circuit design space show that the time-to-analog-based designs introduced in this work can produce highly exponential and analytical transfer functions, but that the less analytically tractable output of the previously proposed filter-based designs can achieve less variability in a smaller footprint. Probabilistic bits (P-bits) composed of the fabricated VRSCs achieve bit flip rates of 50 MHz and allow at least one order of magnitude of control over their simulated annealing temperature.

Intrinsically random hardware devices are increasingly attracting attention for their potential use in probabilistic computing architectures. One such device is the single-photon avalanche diode (SPAD) and an associated functional unit, the variable-rate SPAD circuit (VRSC), recently proposed by us as a source of randomness for sampling and annealing Ising and Potts models. This work develops a more advanced understanding of these VRSCs by introducing several VRSC design options and studying their tradeoffs as implemented in a 65-nm CMOS process. Each VRSC is composed of a SPAD and a processing circuit. Combinations of three different SPAD designs and three different types of processing circuits were evaluated on several metrics such as area, speed, and variability. Measured results from the SPAD design space show that even extremely small SPADs are suitable for probabilistic computing purposes, and that high dark count rates are not detrimental either, so SPADs for probabilistic computing are actually easier to integrate in standard CMOS processes. Results from the circuit design space show that the time-to-analog-based designs introduced in this work can produce highly exponential and analytical transfer functions, but that the less analytically tractable output of the previously proposed filter-based designs can achieve less variability in a smaller footprint. Probabilistic bits (P-bits) composed of the fabricated VRSCs achieve bit flip rates of 50 MHz and allow at least one order of magnitude of control over their simulated annealing temperature.

Abstract The paper tackles the problem of joint deconvolution and segmentation of textured images. The images are composed of regions containing a patch of texture that belongs to a set of K possible classes. Each class is described by a Gaussian random field with parametric power spectral density whose parameters are unknown. The class labels are modelled by a Potts field driven by a granularity coefficient that is also unknown. The method relies on a hierarchical model and a Bayesian strategy to jointly estimate the labels, the K textured images in addition to hyperparameters: the signal and the noise levels as well as the texture parameters and the granularity coefficient. The capability to estimate the latter is an important feature of the paper. The estimates are designed in an optimal manner as a risk minimizer that yields the marginal posterior maximizer for the labels and the posterior mean for the rest of the unknowns. They are computed based on a convergent procedure from samples of the posterior obtained through an advanced MCMC algorithm: Perturbation-Optimization step and Fisher Metropolis-Hastings step within a Gibbs loop. Various numerical evaluations provide encouraging results despite the strong difficulty of the problem.

The present study aimed to investigate the clinical effects of the brand new perioperative transfusion trigger score (POTTS) system in patients undergoing malignant tumor surgeries. 442 cases of patients diagnosed with malignant tumor were randomly selected (from January 2012 to December 2016) from Zunyi Medical University and were divided into 3 experimental groups. Patients in the POTTS group were transfused by the POTTS guideline perioperatively, while patients in the 7–10 g group were treated by the traditional transfusion guidelines existed (restrictive transfusion strategy), patients in the 10 g group should be transfused to keep the Hb level no less than 10 g/dL (liberal transfusion strategy). Baseline information, operation time, bleeding volume, transfusion amount, incision healing time, postoperative complications, metastasis and recurrence were observed and recorded. Postoperative short-term mortality was comparable of the 3 groups, 3 cases of death all occurred in 10 g group, there was no significant difference in the incidence of postoperative complications, including infectious complications and coagulation related complications. Follow-up to date, there were 25 cases, 29 cases and 29 cases of tumor recurrence and metastasis in the three groups, but no statistical difference observed. The present findings show that the POTTS transfusion system is more advantageous with regard to save blood and relieve economic burdens of patients, and does not affect the long-term recurrence and metastasis rate of malignant tumor. [ABSTRACT FROM AUTHOR]

Intrinsically random hardware devices are increasingly attracting attention for their potential use in probabilistic computing architectures. One such device is the single-photon avalanche diode (SPAD) and an associated functional unit, the variable-rate SPAD circuit (VRSC), recently proposed by us as a source of randomness for sampling and annealing Ising and Potts models. This work develops a more advanced understanding of these VRSCs by introducing several VRSC design options and studying their tradeoffs as implemented in a 65-nm CMOS process. Each VRSC is composed of a SPAD and a processing circuit. Combinations of three different SPAD designs and three different types of processing circuits were evaluated on several metrics such as area, speed, and variability. Measured results from the SPAD design space show that even extremely small SPADs are suitable for probabilistic computing purposes, and that high dark count rates are not detrimental either, so SPADs for probabilistic computing are actually easier to integrate in standard CMOS processes. Results from the circuit design space show that the time-to-analog-based designs introduced in this work can produce highly exponential and analytical transfer functions, but that the less analytically tractable output of the previously proposed filter-based designs can achieve less variability in a smaller footprint. Probabilistic bits (P-bits) composed of the fabricated VRSCs achieve bit flip rates of 50 MHz and allow at least one order of magnitude of control over their simulated annealing temperature.

We study the orientation of rods in the neighborhood of a surface. A semi-infinite region in two different situations is considered: (i) the rods are located close to a flat wall and (ii) the rods occupy the space that surrounds a sphere. In a recent paper we investigated a similar problem: the interior of a sphere, with a fixed concentration of rods. Here, we allow for varying concentration, the rods are driven from a reservoir to the neighborhood of the surface by means of a tunable chemical potential. In the planar case, the particle dimensions are irrelevant. In the curved case, we consider cylinders with dimensions comparable to the radius of curvature of the sphere; as they come close to the surface, they have to accommodate to fill the available space, leading to a rich orientational profile. These systems are studied by a mapping onto a three-state Potts model with annealed disorder on a semi-infinite lattice; two order parameters describe the system: the occupancy and the orientation. The Hamiltonian is solved using a mean-field approach producing recurrence relations that are iterated numerically and we obtain various interesting results: the system undergoes a first order transition just as in the bulk case; the profiles do not have a smooth decay but may present a step and we search for the factors that determine their shape. The prediction of such steps may be relevant in the field of self-assembly of colloids and nanotechnology.

We study the orientation of rods in the neighborhood of a surface. A semi-infinite region in two different situations is considered: (i) the rods are located close to a flat wall and (ii) the rods occupy the space that surrounds a sphere. In a recent paper we investigated a similar problem: the interior of a sphere, with a fixed concentration of rods. Here, we allow for varying concentration, the rods are driven from a reservoir to the neighborhood of the surface by means of a tunable chemical potential. In the planar case, the particle dimensions are irrelevant. In the curved case, we consider cylinders with dimensions comparable to the radius of curvature of the sphere; as they come close to the surface, they have to accommodate to fill the available space, leading to a rich orientational profile. These systems are studied by a mapping onto a three-state Potts model with annealed disorder on a semi-infinite lattice; two order parameters describe the system: the occupancy and the orientation. The Hamiltonian is solved using a mean-field approach producing recurrence relations that are iterated numerically and we obtain various interesting results: the system undergoes a first order transition just as in the bulk case; the profiles do not have a smooth decay but may present a step and we search for the factors that determine their shape. The prediction of such steps may be relevant in the field of self-assembly of colloids and nanotechnology. [ABSTRACT FROM AUTHOR]

Study Design: Bibliometric review of the literature., Objective: This bibliometric analysis aims to give an overview of the most influential academic literature written on spinal tuberculosis., Methods: All databases included in the Thomson Reuters Web of Knowledge were searched for the most influential publications in spinal tuberculosis. The most cited articles published between 1950 and 2015, with the main focus on orthopedic surgery, were identified using a multistep approach, and a total of 100 articles were included. The publications were then analyzed in this bibliometric analysis., Results: The number of citations ranged from 243 to 36, with an average of 77.11. The articles were published in 34 different journals, and the studies were conducted in 20 different countries. The top 3 countries, India, the United States, and China, published a total of 51% (n = 51) of all articles. Low-burden countries produced 60% (n = 60) of all articles in our list. African centers produced only 4% (n = 4) of all included articles., Conclusions: Indian and Chinese researchers dominate evidence in spinal tuberculosis. Other areas with high disease burden, such as Africa, do not feature. Most publications are retrospective studies with a low level of evidence., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.