Statistical Physical Properties of Four-Wave Mixing Optical Neural Network

Исследованы статфизические свойства оптической нейросети. Получены условия, при которых возможно обучение нейросети алгоритмом максимального правдоподобия. Исследование проведено на примере трехмерной модели Изинга, в которой последовательно добавляется дальнодействие так, что в пределе модель можно описывать теорией среднего поля. Получены аналитические оценки для критической температуры нейросети при учете взаимодействия со вторыми и третьими соседями. Данные оценки на всем интервале значений параметров взаимодействия хорошо согласуются с результатами, полученными методами Монте-Карло. Установлено, что с ростом числа положительных межсвязей величина критической температуры падает и алгоритм максимального правдоподобия может применяться практически без ограничений. The paper investigates the statistical physical properties of an optical neural network. The conditions for training a neural network by the maximum likelihood algorithm are identified. The study uses a three-dimensional Ising model, to which a long-range action is sequentially added so that in the limit the model can be described by the mean-field theory. Analytical estimates of the critical neural network temperature were obtained considering the interaction with the second and third-order neighbors. The estimates for the entire interval of the interaction parameters are in good agreement with the results obtained by Monte Carlo methods. It is found that as the number of positive interconnections increase, the critical temperature value decreases and the maximum likelihood algorithm can be applied virtually without any restrictions.

Lithofacial Interpretation of the Section in the Core Absence Intervals Using Microimager Data

This work is devoted to a new direction for geology – interpretation of studied section of sediments through the analysis of microimager data. Imager analysis provides important information about the structural and textural features of rocks, nature of stratification, structural occurrence of the section, natural and technogenic fracturing. The use of borehole microimages in geological and field studies allows us to deepen and expand the existing ideas about the geological structure of known hydrocarbon deposits, and the integrated use of images allows us to solve narrowly focused tasks (Rybalchenko et al., 2016). It is worth to notice that today the potential of reservoir microimagers as a geological GIS tool is underestimated (Isotova et al., 1993) (Mathis et al., 1995) (Donselaar et al., 2005). The most widespread development of borehole imagers abroad occurred in the mid-80s of the XX century. Currently, their use is still gaining popularity in Russia. The use of microimages is not limited to the open trunk of a drilled well, technologies that allow obtaining images directly during drilling are available and widely used (Rybalchenko et al., 2016). From the point of view of well productivity, they can be used to characterize such key parameters as the orientation of horizontal stresses, as well as the intervals of anisotropy, secondary porosity, fracturing and possible crack spread during hydraulic fracturing (Climer et al., 2015). Fine structural and textural features of the section can be used for sedimentological analysis, which means the study of sedimentary rocks in order to establish the processes of their formation - the transport of material, the accumulation of sediments and their diagenetic transformations (Nichols et al., 1999). This analysis is based on the principle of actualism and is carried out using the latest results of studying modern sedimentation processes (Prothero et al., 1996). Imagers are divided into the degree of detail and the scale of measurements:Microimagers – a number of GIS devices, the result of which are images (well scan) with an axial resolution of no more than 1 cm, with a maximum coverage of the wellbore of at least 75% and having a correction for uneven movement and for the intervals of puffs (FMI, FMI-HD, QGEO, QGEO Slim, TBEI of the Wireline division, and also MicroScope HD devices).Imagers – a number of GIS devices, the result of which is images with an axial resolution of no more than 10 cm and/or with a maximum coverage of the wellbore of at least 50%. (FMS, DOBMI, OBMI, UBI divisions of Wireline, and also MicroScope and GeoVISION devices).Macroimagers – a number of GIS devices, the result of which is images (well scan) with an axial resolution of more than 10 cm (geoVISION, EcoScope). Imager - a graphical representation of the walls of the well. It is the result of recording a number of GIS devices. In the diagrams, it is a scan of the cylinder from 0 to 360 degrees, oriented to the cardinal directions relative to the true north or relative to the "top" of the well (Top of Hole). In this paper, authors show the advantages of microimagers over the informativeness of a standard GIS complex and sedimentological core study, and also describes cases when the informativeness of a microimager is not inferior to the informativeness of core data. Authors understand that core is the most important link in the chain of studying the geological structure of the deposit. Nevertheless, it is difficult to characterize the entire interval of the formation using only the core, both for geological and technological reasons. At the same time, imagers can be used not only as a qualitative, but also a quantitative source of visual information (Brown et al., 2015).

Heart rate monitoring of the endurance runner during high intensity interval training: Influence of device used on training functions

Photoplethysmography (PPG) heart rate devices are greatly affected by the motion artifacts of running. As a result, their application in training load systems and effort control strategies based on heart rate (HR) could be debatable. In 2019, Polar applied some new features on their PPG devices to improve their accuracy. Thus, the purpose of this study was to determine the level of agreement between the new PPG system Polar Precision Prime™ and the chest strap Polar H10 (reference system) in the HR monitoring during an interval running protocol. A group of 37 long distance runners completed an interval running protocol of 10 min composed of five 1-min trials with an active break of 1-min between each trial. An excellent reliability (ICC > 0.9) was obtained for the entire interval running protocol with the lowest values in the first 2 min (ICC = 0.960–0.949), slight differences between intensities (ICC = 0.992–0.986), and a reduction of the observed tendency (ICC > 0.9) when the Edwards quantification model was applied (ICC = 0.877–0.967). The Bland-Altman plots with the final HR values of each trial establish a systematic bias (<1 bpm) for all intervals with a random error (<4 bpm), except in the first trial which had a higher random error (6.85 bpm). In conclusion, the innovations applied in the new PPG system provide the accuracy required for use in diverse functions, including endurance running.

Environmental evolution, faunal and human occupation since 2 Ma in the Anagni basin, central Italy

We present the study of a composite, yet continuous sedimentary succession covering the time interval spanning 2.6–0.36 Ma in the intramontane basin of Anagni (central Italy) through a dedicated borecore, field surveys, and the review of previous data at the three palaeontological and archaeological sites of Colle Marino, Coste San Giacomo and Fontana Ranuccio. By combining the magneto- and chronostratigraphic data with sedimentologic and biostratigraphic analysis, we describe the palaeogeographic and tectonic evolution of this region during this entire interval. In this time frame, starting from 0.8 Ma, the progressive shallowing and temporary emersion of the large lacustrine basins and alluvial plains created favorable conditions for early hominin occupation of the area, as attested by abundant tool industry occurrences and fossils. This study provides new constraints to better interpret the hominin migratory dynamics and the factors that influenced the location and spatial distribution during the early occupation of this region.

Saving 2.2 Days from Drilling in Hard and Abrasive Sandstone Formation with Innovative 360 Rolling Diamond Element Bit Technology

This project drilled in Sin Phu Horm field. The main challenge in this field is the formation. The 8.5-in section is designed to drill through the hard and abrasive sandstone formation (known as Nam Phong formation) with unconfined compressive strength (UCS) between 6,000 and 24,000 psi and peak up to 55,000 psi. Multiple bit runs and heavy set of Polycrystalline Diamond Compact (PDC) bits were observed in the offset wells with slow rate of penetration (ROP) and short intervals, which resulted in a high drilling cost. In the offset runs, the average interval was observed between 200 and 300 meters and average on-bottom ROP ranged from 2 to 8 m/hr. Worn cutters were the main dull characteristic in the offset PDC bits and the bits were pulled out of hole due to slow ROP. Due to the challenging formation, the goal was to increase the interval per bit run and ROP which resulted to reduce the number of bit trips and drilling cost. Looking at the dull grading of the offset PDC bits, it was obvious that the slow ROP was caused by the cutters worn by the abrasive and hard Nam Phong formation. The fixed-cutter PDC bits were run in the offset wells and worn cutters were observed in the shoulder area. The worn portion of the cutter occurred only in the exposed side, while the portion in the cutter pocket remained intact. Utilizing the portion in the cutter pocket helps to prolong cutter life, increase the ROP, and bit life longevity. Thus, it can help to reduce undesired bit trips. Based on the worn cutter observation, the new design of the 8.5-in PDC bit equipped with innovative 360 rolling cutter (RC) bit was proposed. A comprehensive vibration simulation drilling parameters roadmap were provided to minimize shock and vibration. Two bits were run with rotary steerable BHA to drill Nam Phong formation in the field. The first bit drilled 431 meters at an average ROP of 6.8 m/hr and the second bit drilled 391 meters at an average ROP of 5.5 m/hr. Two runs using the 360 RC bits drilled 822 meters in total of 1,236 meters entire interval of Nam Phong formation, which was equivalent to 66%, achieving the operator's goal while saving 2.2 days solely from two runs of RC bit. This success increased the operator's confidence to run 360 RC bits in the subsequent wells to reduce the number of bit trips and increase the ROP. This paper will discuss the application and evolution of 360 RC bit, along with the result achieved by the bit fitted equipped with this cutter in Thailand onshore.

A Bivariate Chebyshev Polynomials Method for Nonlinear Dynamic Systems With Interval Uncertainties

A bivariate Chebyshev polynomials approach is proposed to estimate the dynamic response bounds of nonlinear systems with interval uncertainties. The existing collocation method directly searches the maximum and minimum values of the surrogate model in the entire interval space by the scanning method (SM). The presence of too many uncertain parameters will lead to expansive computational cost. To overcome this shortcoming, the dynamic response is decomposed by a bivariate function decomposition (BFD), established based on high-order Taylor expansion, into the sum of multiple univariate and bivariate response functions. The above univariate and bivariate functions are fitted using Chebyshev polynomials, and polynomial coefficients are obtained through one-dimensional (1D) and two-dimensional (2D) interpolation points. Thus, the solution of the nonlinear dynamic systems with uncertain parameters can be transformed into that of univariate and bivariate Chebyshev interval functions. The extremum values of the low-dimensional Chebyshev interval functions can be found by SM, and then the bounds of dynamic response are acquired by interval arithmetic. Since SM searches for extreme values only in 1D and 2D uncertain domains, the amount of calculation is reduced compared to searching the whole uncertain space. The efficiency, practicability and effectiveness of the proposed interval uncertainty analysis method are proved by three dynamic examples.

Turn Around Time for Clinical Biochemistry Laboratory: A Vital and Effective Parameter for Patient Care

Introduction: Clinical laboratories are judged by its validity, reliability, genuineness or authenticity and its timeliness in reports generating. Repetitively, patients and physicians complain about the time taken by the laboratory for the investigation. The total Turn Around Time (TAT) for laboratory tests includes the entire interval from the order of the test to the awareness of the result by the clinicians. The evaluation and improvement of TAT is crucial for the management of laboratory quality and the satisfaction of patients. Aim: To observe the TAT of common biochemical investigations, to identify reasons for increased TAT and to formulate a plan to rectify increased TAT. Materials and Methods: A hospital based cross-sectional study was conducted at the Clinical Biochemistry Section of the Central Diagnostic Laboratory of Tertiary Care Hospital. TAT data from April 2014 to September 2015 were included in the study. The laboratory technicians and the resident doctors of biochemistry recorded the reasons for the delay of those specimens exceeding the TAT. Data were analysed with the help of statistical software Epi Info 7. Results: The total number of samples received in the biochemistry laboratory were 1,85,658. Out of this, Out Patient Department (OPD) samples were 1,35,022 and Intensive Care Unit (ICU) samples were 50,636. Pre-analytical errors were observed in 670 of ICU samples, which was 1.32% of total samples received and it was higher than the post-analytical errors. In the pre-analytical phase, the most common cause was inaccurate procedures of sample collection. Conclusion: This study demonstrates that the main culprit of increased TAT was delay in the sample transportation and Haemolysed samples. TAT minimisation is a constant procedure for any facility. Every laboratory needs to develop a decent approach for reducing the TAT.

Lithological attributes of hd-001 well, shallow offshore, Niger delta basin, Nigeria

Lithological analysis was carried out on 96 ditch cuttings samples from HD-001 well located within the shallow offshore Niger delta basin, Nigeria. Three lithofacies sequences were delineated by the integration of wireline logs textural/lithologic attritudes and the distribution of index accessory minerals. They are transitional paralic, paralic and marine paralic sequences. The lithologic, textural and wireline log data indicate that the entire interval studied in the HD-001 well belongs to the Agbada Formation. The Formation is made up of alternating sand and shale units which suggests rapid shoreline progradation. The grain size increases from essentially fine to medium-grained at the basal part of the well to dominantly coarser grain at the upper part. The index accessories recognize shallow marine to coastal deltaic settings environment of deposition. Sand bodies which represent sub-environments within those settings are deposited in sequences. Each sequence begins with a transgressive phase followed by significant regressions.

Fast Switch and Spline Function Inversion Algorithm with Multistep Optimization and k-Vector Search for Solving Kepler’s Equation in Celestial Mechanics

Obtaining the inverse of a nonlinear monotonic function f(x) over a given interval is a common problem in pure and applied mathematics, the most famous example being Kepler’s description of orbital motion in the two-body approximation. In traditional numerical approaches, this problem is reduced to solving the nonlinear equation f(x)−y=0 in each point y of the co-domain. However, modern applications of orbital mechanics for Kepler’s equation, especially in many-body problems, require highly optimized numerical performance. Ongoing efforts continually attempt to improve such performance. Recently, we introduced a novel method for computing the inverse of a one-dimensional function, called the fast switch and spline inversion (FSSI) algorithm. It works by obtaining an accurate interpolation of the inverse function f−1(y) over an entire interval with a very small generation time. Here, we describe two significant improvements with respect to the performance of the original algorithm. First, the indices of the intervals for building the spline are obtained by k-vector search combined with bisection, thereby making the generation time even smaller. Second, in the case of Kepler’s equation, a multistep method for the optimized calculation of the breakpoints of the spline polynomial was designed and implemented in Cython. We demonstrate results that accurately solve Kepler’s equation for any value of the eccentricity e∈[0,1−ϵ], with ϵ=2.22×10−16, which is the limiting error in double precision. Even with modest current hardware, the CPU generation time for obtaining the solution with high accuracy in a large number of points of the co-domain can be kept to around a few nanoseconds per point.

Female Breast Cancer in Suriname: Pathways to Treatment—A Patient’s Perception

PURPOSE Delays across the entire cancer care continuum are not uncommon. This cross-sectional study explored the health care trajectories of Surinamese women with breast cancer and identified predictors of timely diagnosis and treatment initiation. METHODS One hundred women age 30 years or older who were newly diagnosed with breast cancer in 2017 to 2018 were recruited from all 4 hospitals in Paramaribo. Data on their demographics, lifestyle, reproductive and medical history, health status, and family history of breast cancer and other malignancies were collected using a validated semistructured questionnaire. Using Anderson’s Model of Pathways to Treatment, we defined a patient interval (from detection to first consultation), diagnostic interval (from consultation to histopathologic diagnosis), and treatment interval (from diagnosis to first treatment). Log-transformed data were analyzed using linear regression, and variables with P ≤ .05 were considered statistically significant predictors of intervals. RESULTS All participants had health insurance and access to health care. Eighty-five percent of patients presented with early-stage disease. Ninety percent of patients had self-detected their disease, with 70% finding a lump. Average age was 55.6 years (± 11.8 years). Median durations of patient, diagnostic, and treatment intervals were 13 days (interquartile, range, 4-63 days), 40 days (IQR, 21-57 days), and 18 days (IQR, 8-38 days), respectively. Median duration of the entire interval was 95 days (IQR, 59-272 days). Patient-related factors associated with the intervals were religion (β = −530; P = .003), being employed (β = 149.4; P = .007), and age 50 years and older (β = −195.8; P = .037). Disease-related factors were lump as first symptom (β = −175.6; P = .038) and late-stage disease at diagnosis (β = 213.5; P = .004). CONCLUSION Given the limited-resource setting, delays in Suriname’s health care can be minimized by programs aimed at increasing breast cancer awareness and education; however, delays may have been underestimated as a result of the over-representation of early-stage disease and recall bias regarding the first symptom detected.