Multiple Counters Research Articles

A new ground level neutron monitor for space weather assessment

We report on a new ground-level neutron monitor design for studying cosmic rays and fluxes of solar energetic particles at the Earth’s surface. The first-of-its-kind instrument, named the NM-2023 after the year it was standardised and following convention, will be installed at a United Kingdom Meteorological Office observatory (expected completion mid 2024) and will reintroduce such monitoring in the UK for the first time since ca. 1984. Monte Carlo radiation transport code is used for the development and application of parameterised models to investigate alternative neutron detectors, their location and bulk material geometry in a realistic cosmic ray neutron field. Benchmarked against a model of the current and most widespread design standardised in 1964 (the NM-64), two main parameterisation studies are conducted; a simplified standard model and a concept slab parameterisation. We show that the NM-64 standard is well optimised for the intended large-diameter boron trifluoride (BF3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_3$$\\end{document}) proportional counters but not for multiple smaller diameter counters. The new design (based on a novel slab arrangement) produces comparable counting efficiencies to an NM-64 with six BF3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_3$$\\end{document} counters and has the added advantage of being more compact, lower cost and avoids the use of highly toxic BF3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_3$$\\end{document}.

Single-photon counting detectors for diffraction-limited light sources

When first introduced, single-photon counting detectors reshaped crystallography at synchrotrons. Their fast readout speed enabled, for example, shutter-less data collection and fine slicing of the rotation angle and boosted the development of new experimental techniques like ptychography. Under optimal conditions, single-photon counting detectors provide an unlimited dynamic range with image noise only limited by the Poisson statistics of the incoming photons. Counting the pulses from individual photons, essentially what made the detectors so successful, also causes the main drawback, which is the loss of efficiency at high photon fluxes due to pulse pileup in the analog front end. To fully take advantage of diffraction-limited light sources, the next-generation single-photon counters need to improve their count rate capabilities in the same order of magnitude as the increased flux. Moreover, fast frame rates (a few kHz) are required to cope with the shorter dwell time achievable, thanks to the higher flux. Detector architecture with multiple comparators and counters can open new possibilities for energy-resolved imaging, while interpixel communication can overcome the issues arising from charge sharing and reduce the loss of efficiency at the pixel corners. Coupling single-photon counting detectors to high-Z sensors for hard X-ray detection (>20 keV) and to low-gain avalanche diodes (LGADs) for soft X-rays is also necessary to make use of the increased coherence of the new light sources over the full radiation spectrum. In this paper, we present possible strategies to improve the performance of single-photon counting detectors at the fourth-generation synchrotron sources and compare them to charge integrating detectors.

Design of a compact long counter with an improved response using multiple point-like thermal neutron counters

Design of a compact long counter with an improved response using multiple point-like thermal neutron counters

Improved in situ analysis of lead isotopes in low-Pb melt inclusions using laser ablation-multi-collector-inductively coupled plasma-mass spectrometry.

In situ Pb isotope analyses of tiny melt inclusions using laser ablation-multi-collector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) are crucial for exploring the origins of mafic lavas. However, quantitative use of this technique with low-Pb (<10ppm) melt inclusions is difficult due to their low 204 Pb content and 204 Hg interference. Pb isotopic ratios of various reference glasses and olivine-hosted melt inclusions were determined using LA-MC-ICP-MS. Multiple ion counters were used to simultaneously determine signal intensities of all Pb isotopes and 202 Hg. An Hg signal-removal smoothing device reduced its signal in the gas blank by >80%. Instrumental mass bias was corrected using the standard-sample bracketing method. With 24-90 μm diameter laser spots, 2-4Hz repetition rates, and 2.5-4J cm-2 energy fluence, the analytical precisions of 20x Pb/204 Pb ratios (x = 6, 7, 8) for standards BHVO-2G, ML3B-G, NIST 614, NKT-1G, T1-G, GOR132-G, and StHs6/80-G were <1.0% (2RSD) when 208 Pb signals >100 000 cps. The Wangjiadashan melt inclusions have 206 Pb/204 Pb = 17.14-18.44, 207 Pb/204 Pb = 15.28-15.66, and 208 Pb/204 Pb = 37.12-38.68. The described method improves the precision and accuracy of in situ Pb isotope analysis in low-Pb melt inclusions using LA-MC-ICP-MS. The Pb isotopic compositions of the Wangjiadashan melt inclusions indicate the coexistence of LoMu and EMII+young HIMU components in the mantle source of weakly alkaline basalts.

Large-batch evaluation of cell counter instrument-to-instrument consistency for cell therapy applications

Abstract Cell therapy has been hailed as a medical revolution, and its rise has only increased the importance of accuracy and precision in cell counting. Ensuring the identity, purity, and viability of cell therapy products is critical for increasing efficacy and avoiding potential harmful side effects. The burden of sample analysis often rests on fleets of automated cell counters, leading to the need for confidence that multiple cell counters will give similar results. In this work we compare groups of two distinct cell counting instruments. The first type is a well-established single-sample counter (Cellometer K2), similar to those often found in R&amp;D laboratories. The second type of instrument (Cellaca MX) is a high-throughput cell counter that is often more suitable for a manufacturing environment than its single-sample counterparts. We test the consistency of these cell counters using both live cells and fluorescent beads. We use samples of Jurkat cells to simulate immunotherapy products, and prepare the beads in fixed reference samples to allow comparison of multiple instruments over extended periods of time. We use these beads to investigate agreement among 60 Cellometer K2 instruments and 30 Cellaca MX instruments, what we believe is the largest group of cell counting instruments to be involved in a single comparison study. Our work illustrates experimental approaches suitable for the comparison of multiple cell counting methods. We measure consistency among the cell counters, both within groups of similar instruments and between instrument types. This consistency encourages optimism for “future-proof” assays that can survive the transition from R&amp;D to production with minimal adjustment.

Avoiding Flow Size Overestimation in Count-Min Sketch With Bloom Filter Constructions

The Count-Min sketch is the most popular data structure for flow size estimation, a basic measurement task required in many networks. Typically the number of potential flows is large, eliminating the possibility to maintain a counter per flow within memory of high access rate. The Count-Min sketch is probabilistic and relies on mapping each flow to multiple counters through hashing. This implies potential estimation error such that the size of a flow is overestimated when all flow counters are shared with other flows with observed traffic. Although the error in the estimation can be probabilistically bounded, many applications can benefit from accurate flow size estimation and the guarantee to completely avoid overestimation. We describe a design of the Count-Min sketch with accurate estimations whenever the number of flows with observed traffic follows a known bound, regardless of the identity of these particular flows. We make use of a concept of Bloom filters that avoid false positives and indicate the limitations of existing Bloom filter designs towards accurate size estimation. We suggest new Bloom filter constructions that allow scalability with the support for a larger number of flows and explain how these can imply the unique guarantee of accurate flow size estimation in the well known Count-Min sketch.

Input-driven multi-counter automata

The model of deterministic input-driven multi-counter automata is introduced and studied. On such devices, the input letters uniquely determine the operations on the underlying data structure that is consisting of multiple counters. We study the computational power of the resulting language families and compare them with known language families inside the Chomsky hierarchy. In addition, it is possible to prove a proper counter hierarchy depending on the alphabet size. This means that any input alphabet induces an upper bound which depends on the alphabet size only, such that k+1 counters are more powerful than k counters as long as k is less than this bound. The hierarchy interestingly collapses at the level of the bound. Furthermore, we investigate the closure properties of the language families. For input-driven multi-counter automata with 0 or 1 counter, we discuss the computational complexity of their decidable problems. For k≥2 counters, the decidability problems of emptiness, finiteness, universality, inclusion, equivalence, regularity, and context-freeness are shown to be non-semidecidable. Finally, we study descriptional complexity aspects of input-driven multi-counter automata. It is shown that a nondeterministic device can be determinized and that 2n−1 is a necessary and sufficient blow-up in the number of states for the determinization. For the operational state complexity of deterministic input-driven multi-counter automata under Boolean operations, tight bounds on the number of states are established. Finally, it turns out that the size trade-offs between deterministic input-driven multi-counter automata with k+1 and k counters are non-recursive, that is, they are not bounded by any recursive function.

Template attacks on ECC implementations using performance counters in CPU

We demonstrate a new set of template attacks on ECC implementations using the performance counters in CPU. Template attacks are powerful mechanisms that can combine statistical intelligence for modelling side channel leakages and can thus compromise complex crypto implementations. Automated attack phases add to the efficiency of this approach. We introduce a new approach of using CPU counter values for constructing templates to carry out attacks on crypto implementations, which also opens up the possibility of many other template attacks that have been demonstrated earlier using power analysis, to be feasible on the modern day architectures. The values obtained from multiple CPU counters are used to generate templates, which are further matched with the traces obtained on the target implementation for guessing the bit values of the secret scalar used during the scalar multiplication function of the ECC implementation. We demonstrate the feasibility of the attack approach on virtualized environments such as the resources of the cloud computing infrastructure. We further model the attack, define the evaluation metrics and demonstrate the effectiveness of the attack approach.

Spectrometry and dosimetry of neutron beams produced by 7Li (p,n) reactions in the proton energy range of 3–5 MeV

Abstract Neutron spectrometry was carried out with a state of art neutron spectrometer system named ROSPEC based on multiple proportional counters, for neutron beams generated by bombarding proton beams on a 7Li target with projectile energy in the range of 3–5 MeV. Along with the neutron spectra, neutron fluence rates and ambient dose equivalent rates at the position of the detector were also measured. Neutron spectra measured by ROSPEC were compared with theoretically simulated neutron spectra. The neutron peak energy correspond to n o group of neutrons was found to be within 10%–15% of the expected peak values (theoretical values). The study also determines the neutron fluence rate and ambient dose equivalent rates per unit beam current for neutron energy below and above 50 keV for the studied proton beams energies. The characterization of the quasi mono-energetic neutron beams could be useful for the purpose of radiation protection of the users of the beam line, Boron neutron Capture Therapy (BNCT), and study of response characteristics of the neutron detectors.

On families of full trios containing counter machine languages

We look at nondeterministic finite automata augmented with multiple reversal-bounded counters where, during an accepting computation, the behavior of the counters is specified by some fixed pattern. These patterns can serve as a useful “bridge” to other important automata and grammar models in the theoretical computer science literature, thereby helping in their study. Various pattern behaviors are considered, together with characterizations and comparisons. For example, one such pattern defines exactly the smallest full trio containing all the bounded semilinear languages. Another pattern defines the smallest full trio containing all the bounded context-free languages. The “bridging” to other families is then applied, e.g. to certain Turing machine restrictions, as well as other families. Certain general decidability properties are also studied using this framework.

The cafeteria problem: order sequencing and picker routing in on-the-line picking systems

This paper is dedicated to the cafeteria problem: given a single waiter operating multiple counters for different dishes arranged along a line and a set of customers with given subsets of dishes they desire, find a sequence of customers, which may not overtake each other, and a service schedule for the waiter, such that the makespan is minimized. This generic problem is shown to have different real-world applications in order picking with blocking restrictions. We present different heuristic and exact solution procedures for both problem parts, i.e., customer sequencing and waiter scheduling, and systematically compare these approaches. Our computational results reveal that the largest performance gains are enabled by not strictly processing order after order. Instead, the waiter should be allowed to flexibly swap between customers waiting along the line. Such a flexible service policy considerably reduces the makespan and the total walking distance of the waiter.

Data Placement Algorithm for Improving I/O Load Balance without Using Popularity Information

Data placement considerably affects the I/O performance of distributed storage systems such as HDFS. An ideal placement algorithm should keep the I/O load evenly distributed among different storage nodes. Most of the existing placement algorithms with I/O load balance guarantee depend on the information of data popularity to make the placement decisions. However, the popularity information is typically not available in the data placement phase. Furthermore, it usually varies during the data lifecycle. In this paper, we propose a new placement algorithm called Balanced Distribution for Each Age Group (BEAG), which makes data placement decisions in the absence of the popularity information. This algorithm maintains multiple counters for each storage node, with each counter representing the amount of data belonging to a certain age group. It ensures that the data in each age group are equally scattered among the different storage nodes. As the popularity variance of the data belonging to the same age group is considerably smaller than that of the entire data, BEAG significantly improves the I/O load balance. Experimental results show that compared to other popularity independent algorithms, BEAG decreases the I/O load standard deviation by 11.6% to 30.4%.

Variations of checking stack automata: Obtaining unexpected decidability properties

We introduce a model of one-way language acceptors (a variant of a checking stack automaton) and show the following decidability properties:1.The deterministic version has a decidable membership problem but has an undecidable emptiness problem.2.The nondeterministic version has an undecidable membership problem and emptiness problem. There are many models of accepting devices for which there is no difference with these problems between deterministic and nondeterministic versions, i.e., the membership problem for both versions are either decidable or undecidable, and the same holds for the emptiness problem. As far as we know, the model we introduce above is the first one-way model to exhibit properties (1) and (2). We define another family of one-way acceptors where the nondeterministic version has an undecidable emptiness problem, but the deterministic version has a decidable emptiness problem. We also know of no other model with this property in the literature. We also investigate decidability properties of other variations of checking stack automata (e.g., allowing multiple stacks, two-way input, etc.). Surprisingly, two-way deterministic machines with multiple checking stacks and multiple reversal-bounded counters are shown to have a decidable membership problem, a very general model with this property.

Trace inclusion for one-counter nets revisited

One-counter nets ( OCN) consist of a nondeterministic finite control and a single integer counter that cannot be fully tested for zero. They form a natural subclass of both One-Counter Automata, which allow zero-tests and Petri Nets/VASS, which allow multiple such weak counters. The trace inclusion problem has recently been shown to be undecidable for OCN. In this paper, we contrast the complexity of two natural restrictions which imply decidability.We show that trace inclusion between a OCN and a deterministic OCN is NL-complete, even with arbitrary binary-encoded initial counter-values as part of the input. Secondly, we show that the trace universality problem of nondeterministic OCN, which is equivalent to checking trace inclusion between a finite system and a OCN-process, is Ackermann-complete.

A multiple ion counter total evaporation (MICTE) method for precise analysis of plutonium by thermal ionization mass spectrometry

This paper presents a total evaporation method for the analysis of sub-picogram quantities of Pu, utilizing an array of multiple ion counters. Data from three standards are presented to assess the utility of the technique. An external precision of 1.5% RSD (2σ) was achieved on aliquots approaching 100 fg for the minor 240Pu isotope. Accurate analysis of <1 femtogram of 240Pu, is achievable, with an external reproducibility of better than 10% RSD (2σ). This new technique represents a significant advance in the total evaporation method and will allow routine measurement of femtogram sized Pu samples by thermal ionization mass spectrometry.

An impulse control approach for optimal maintenance scheduling of a gas turbine

AbstractToday gas turbine outages are determined by one global life counter and deterministic life times. In the future the gas turbine will be equipped with multiple life counters for outage determination. Therefore we present an impulse control approach which takes the probabilistic nature of the damage mechanism into account to calculate an optimized maintenance schedule. (© 2016 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Time resolution of time-of-flight detector based on multiple scintillation counters readout by SiPMs

A new timing detector measuring ∼50MeV/c positrons is under development for the MEG II experiment, aiming at a time resolution σt∼30ps. The resolution is expected to be achieved by measuring each positron time with multiple counters made of plastic scintillator readout by silicon photomultipliers (SiPMs). The purpose of this work is to demonstrate the time resolution for ∼50MeV/c positrons using prototype counters. Counters with dimensions of 90×40×5mm3 readout by six SiPMs (three on each 40×5mm2 plane) were built with SiPMs from Hamamatsu Photonics and AdvanSiD and tested in a positron beam at the DAΦNE Beam Test Facility. The time resolution was found to improve nearly as the square root of the number of counter hits. A time resolution σt=26.2±1.3ps was obtained with eight counters with Hamamatsu SiPMs. These results suggest that the design resolution is achievable in the MEG II experiment.

Performance analysis of Cellular Automata HPC implementations

Cellular Automata (CA) are of interest in several research areas and there are many available serial implementations of CA. However, there are relatively few studies analyzing in detail High Performance Computing (HPC) implementations of CA which allow research on large systems. Here, we present a parallel implementation of a CA with distributed memory based on MPI. As a first step to insure fast performance, we study several possible serial implementations of the CA. The simulations are performed in three infrastructures, comparing two different microarchitectures. The parallel code is tested with both Strong and Weak scaling, and we obtain parallel efficiencies of ∼ 75%–85%, for 64 cores, comparable to efficiencies for other mature parallel codes in similar architectures. We report communication time and multiple hardware counters, which reveal that performance losses are related to cache references with misses, branches and memory access.

A case study of air quality above an urban roof top vegetable farm

The effect of elevation and rooftop configuration on local air quality was investigated at the Brooklyn Grange rooftop farm during a short-term observational campaign. Using multiple particle counters and sonic anemometers deployed along vertical gradients, we found that PM2.5 concentration decayed with height above the street. Samples adjacent to the street had the highest average PM2.5 concentration and frequent stochastic spikes above background. Rooftop observations 26 m above ground showed 7–33% reductions in average PM2.5 concentration compared with the curbside and had far fewer spikes. A relationship between the vertical extinction rate of PM2.5 and atmospheric stability was found whereby less unstable atmosphere and greater wind shear led to greater PM2.5 extinction due to damped vertical motion of air.

Design and Implementation of an On-Chip Test Generation Scheme Based on Reconfigurable Run-Time Programmable and Multiple Twisted-Ring Counters

Built-in-self-test (BIST) has emerged as a very effective solution to VLSI testing problems. Related work based on single fixed-order twisted-ring-counter design requires longer testing time to achieve high fault coverage and large storage space to store the seeds and the control data. By using multiple programmable twisted-ring-counters (PTRC), a considerable reduction in test application cycles were achieved. In this paper, an on-chip test generation scheme based on reconfigurable run-time programmable multiple twisted-ring-counters is proposed to generate more number of different test patterns based on the requirements. The design was modeled in VHDL and simulated and synthesized using Xilinx ISE 14.2.