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Violations in the timing constraints of a clocked register can cause a synchronous system to malfunction. The effects of parameter variations on the timing characteristics of registers that determine the timing constraints are investigated in this paper. The sensitivity of the setup time and data propagation delay to variations in power supply voltage, temperature, and gate oxide thickness is demonstrated for four different register designs. Furthermore, design modifications are proposed that enhance the robustness of each register to variation effects.

This research work focuses on implementation of the FinFET-based complementary metal-oxide-semiconductor (CMOS) Full Adder circuits for different transistor configurations using ASAP7 FinFET model. First, this work examines FinFET-based AND-OR-invert (AOI) gates using different topologies, and second, a FinFET-based CMOS Full Adder circuit at the 7nm technology node is analyzed with respect to its process, voltage and temperature (PVT) variability effect measured in terms of the normalized standard deviation of different performance metrics. The comparison is made between conventional (CFFA1) and proposed (FFA2, FFA3, FFA4, FFA5, FFA6, FFA7 and FFA8) FinFET-based CMOS full adder circuits. The aim is to determine the optimal design configuration of the FinFET full adder circuit with the minimum impact of PVT variability. On examining the power delay product (PDP) variability, it is found that variations in FFA2, FFA3, FFA4, FFA5, FFA6, FFA7 and FFA8 are significantly lower than CFFA1 by 6.30%, 4.68%, 10.30%, 65.48%, 68.05%, 65.61% and 17.20%, respectively. Among all the proposed configurations, normalized standard deviation $\sigma /\mu (\%)$ for the PDP metric is lowest in FFA6, followed by FFA7, FFA5, FFA8, FFA4, FFA2 and FFA3. The normalized standard deviation $\sigma /\mu (\%)$ for power dissipation, however, is lowest in FFA8. In addition, a layout comparison analysis of conventional and proposed full adder circuits reveals that FFA7 has the least area, followed by FFA8, FFA6, FFA5, FFA3, FFA4, FFA2 and CFFA1. The area of FFA2, FFA3, FFA4, FFA5 and FFA6 has decreased by 3.29%, 3.51%, 3.50%, 5.14% and 5.52%, while FFA7 and FFA8 have experienced a decrease in area by 13.87% and 14.36%, respectively, as compared to conventional CFFA1. The proposed layout of FinFET-based CMOS Full Adders can be directly transferred into the foundry’s production line for manufacturing purposes. The overall investigation led us to conclude that FFA8 is the most efficient of all due to the lowest power variation, lower delay variation and lower PDP variation, moreover it has a reduced layout area among all the discussed designs. However, there is a tradeoff in terms of penalty in nominal power, propagation delay and PDP in the proposed topologies.

We report our results on nonperiodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly shape similar to a chaotic attractor of Lorentz type. The suitable recurrence plot shows that the dynamics of the combustion is a nonlinear multidimensional process mediated by stochastic noise.

In a software product family context, software architects design architectures that support product diversification in both space (multiple contexts) and time (changing contexts). Product diversification is based on the concept of variability: a single architecture and a set of components support a family of products. Software product families have to support increasing amounts of variability, thereby making variability engineering a primary concern in software product family development. The first part of this paper (1) suggests a two-dimensional, orthogonal categorization of variability realization techniques and classifies these variability categories into system maturity levels. The second part (2) discusses a case study of an industrial software product family of mobile communication infrastructure for professional markets such as the military. The study categorizes and classifies the variability in this product family according to criteria common to virtually all software development projects.

Software Product-Line Engineering (SPLE) is composed of two areas, namely domain engineering and application engineering. Domain engineering is associated with product-line architecture, which is a core asset of the product-line. One of the key issues of the software product-line, especially in domain engineering, is handling the variability among product families. That is, variation management for the software product-line architecture determines the success of software development. Therefore, this paper proposes processes and artifacts to build the software product-line architecture and to manage uniform variability over the life cycle of software product-lines. Furthermore, a case study, namely, the Electronic Medical Record (EMR) system, is presented.

We study the variability properties of the prompt emission of Gamma-Ray Bursts in the gamma-ray energy range. We use the power spectrum analysis in the time domain as developed by [Margutti, in preparation]; this technique is suitable to study the rms variations at different time scales. The timing analysis of 252 Swift light-curves in the 15–150 keV energy range reveals the existence of different variability classes. Moreover, after accounting for the cosmological time dilation, the distribution of the GRB characteristic variability time scales is found to cluster around 0.6–1 s we identify this time scale as a characteristic variability time scale of long GRBs in the source rest frame.

Cell proliferation is considered as a periodic process which is governed by a two-variable relaxation timer. The collective behavior of a system composed of three identical relaxation oscillators is numerically studied under the condition that diffusion of the slow mode (inhibitor) dominates. The phase diagrams for cyclic and linear configurations show unexpectable diversity of stable periodic regimes, some of them are only observable under intermediate but reasonable values of coupling and stiffness. For cyclic configuration we demonstrate: (1) the existence of three periodic regimes with different periods and phase relations and unsymmetrical stable steady state (USSS); (2) the coexistence of in-phase oscillations and USSS; (3) the coexistence of periodic attractors and (4) the emergence of special kind of rotating wave which is manifested as two-loop limit cycle. The natural asymmetry of linear configuration leads to the appearance of many periodic attractors. The most of them are characterized by the large period oscillations of the middle element which has the step-like dependence of period versus coupling. The qualitative reasons for such a diversity and its possible role in the generation of cell cycle variability are discussed.

The development of neuronal branching patterns mainly proceeds by branching events at terminal segments. The randomness in the occurrences of these events is the major cause of the variability that is observed in the final topological structures of neuronal trees. A general observation in neuronal trees is the existence of a branch power relation between the diameters of the segments at branch points. Because of this correlation, total area and volume will become dependent on branching pattern topology. A quantitative assessment of this finding is given. How topological variation propagates into variation in total area and volume, using topological growth models for producing random tree topologies and a simple metrical parametrization is discussed.

When using the ordered weighted average operator, it can happen that one wants to optimize the variability (measured by the entropy (maximal) or by the variance (minimal)) of the weights while keeping the orness of this operator at a fixed level. This has been considered by several authors. Dually, there might be some contexts where one wishes to maximize the orness while guaranteeing some fixed variability. In this paper, we present two algorithms for finding such weights, when the variability is captured by the entropy and by the variance.

The aim of this paper is to evaluate the association between four simple B-mode image descriptors and age, to further assess the association between the descriptors and automated intima-media thickness (IMT) and intima-media thickness variability (IMTV) measurements, and finally analyze the predictive value of the B-mode image descriptors. A database of 1774 images of the carotid artery is used to manually calculate the contrast and the signal-to-noise ratio (SNR) between the (i) intima-media complex and lumen, and (ii) adventitial wall layer and intima-media complex. A subset of 200 images is then used to automatically measure the IMT and IMTV parameters with a previously developed algorithm. Correlation studies and logistic regression analysis are then performed. The contrast and SNR between the intima-media complex and lumen (contrast_IM and SNR_IM) are 112.691$\pm$247.427 and 19.542$\pm$6.236, respectively; whereas between the adventitial wall layer and intima-media complex the parameters (contrast_ADV and SNR_ADV) are found to be 1.684$\pm$1.182 and 32.859$\pm$10.766, respectively. Pearson’s rho is significantly different from zero considering the contrast_IM and the SNR_ADV descriptors when tested for the association with age. The automated IMT and IMTV measurements are 0.796$\pm$0.152mm and 0.096$\pm$0.044mm, respectively. Testing the association with the IMT and IMTV measurements yielded Pearson’s rho values which are significantly different from zero except in the case of contrast_IM for the IMTV measurement. The logistic regression results showed the IMTV measurement and the SNR descriptor between the intima-media complex and the lumen has a significant predictive value. Considering the association between the IMT and IMTV, the B-mode image descriptors showed a strong and statistically significant association. Moreover, the SNR between the intima-media complex and lumen is found to be a predictive variable in demonstrating its effectiveness as an image descriptor.

Recent computational modeling of early fruit fly (Drosophila) development has characterized the degree to which gene regulation networks can be robust to natural variability. In the first few hours of development, broad spatial gradients of maternally derived transcription factors activate embryonic gap genes. These gap patterns determine the subsequent segmented insect body plan through pair-rule gene expression. Gap genes are expressed with greater spatial precision than the maternal patterns. Computational modeling of the gap–gap regulatory interactions provides a mechanistic understanding for this robustness to maternal variability in wild-type (WT) patterning. A long-standing question in evolutionary biology has been how a system which is robust, such as the developmental program creating any particular species’ body plan, is also evolvable, i.e. how can a system evolve or speciate, if the WT form is strongly buffered and protected? In the present work, we use the WT model to explore the breakdown of such Waddington-type ‘canalization’. What levels of variability will push the system out of the WT form; are there particular pathways in the gene regulatory mechanism which are more susceptible to losing the WT form; and when robustness is lost, what types of forms are most likely to occur (i.e. what forms lie near the WT)? Manipulating maternal effects in several different pathways, we find a common gap ‘peak-to-step’ pattern transition in the loss of WT. We discuss these results in terms of the evolvability of insect segmentation, and in terms of experimental perturbations and mutations which could test the model predictions. We conclude by discussing the prospects for using continuum models of pattern dynamics to investigate a wider range of evo-devo problems.

In the past few years, the electronics industry has undergone an explosion in new products and technologies. This fierce global competition has resulted in the decision by many companies to outsource manufacturing in order to concentrate on research and development, marketing, and sales. This has given rise to a number of companies who solely provide electronics manufacturing services. Exchange of information between product developers and contract manufacturers, especially information about product demand, is critical to the success of this business model. In this paper, we analyze forecast data obtained from a local contract manufacturer in order to better understand forecast variability and its reasons. We find that forecast variability tends to increase as the production period approaches, despite common belief that forecasts get better with time. We also discuss the impact that chronic material unavailability and product mix have on forecast variability. Finally, we see that unmet demand pushed in the next production period can distort forecasts and result in unrealistic expectations.

Background: Range of motion (ROM) asymmetry between sides is one indicator of a positive neurodynamic test, but this has been less well studied for the ulnar nerve.

Objective: The purpose of this study was to investigate side-to-side variation in elbow ROM during an ulnar neurodynamic test sequence, including contralateral cervical side flexion, in 40 asymptomatic subjects.

Methods: A traditional goniometer was used to measure elbow flexion ROM at two end points, onset of resistance ($R$1) and symptom onset ($P$1). Two repeated measures of $R$1 and $P$1 were taken on each side.

Results: Reliability for $R$1 and $P$1 was found to be good (ICC $\ge 0.83$, SEM $\le 5.37$) with no significant difference in mean ROM between sides. A significant relationship between sides was seen ($r$ values $\ge 0.48$) and $R^2$ values $>0.23$; this indicates at least 23% of the variance observed in one limb was accounted for by range in the opposite limb. This relationship was slightly stronger for $R$1 than $P$1. Lower bound scores indicate that intra-individual ROM difference $>23^{°}$ for $R$1 and 22^° for $P$1 would exceed normal ROM asymmetry.

Conclusion: These findings provide clinicians with background information of ROM asymmetry during the ulnar neurodynamic test.

Large modifications of seismic waves are produced by variations of material properties near the Earth's surface and by both surface and buried topography. These modifications, usually referred to as "site response", in general lead to larger motions on soil sites than on rock-like sites. Because the soil amplifications can be as large as a factor of ten, they are important in engineering applications that require the quantitative specification of ground motions. This has been recognised for years by both seismologists and engineers, and it is hard to open an earthquake journal these days without finding an article on site response. What is often missing in these studies, however, are discussions of the uncertainty of the predicted response. A number of purely observational studies demonstrate that ground motions have large site-to-site variability for a single earthquake and large earthquake-location-dependent variability for a single site. This variability makes site-specific, earthquake-specific predictions of site response quite uncertain, even if detailed geotechnical and geological information is available near the site. Predictions of site response for average classes of sites exposed to the motions from many earthquakes can be made with much greater certainty if sufficient empirical observations are available.

The 4m International Liquid Mirror Telescope (ILMT) is a zenith-pointing optical observing facility at ARIES Devasthal observatory (Uttarakhand, India). The first light preparatory activities of the ILMT were accomplished in April 2022 followed by on-sky tests that were carried out at the beginning of May 2022. This telescope will perform a multi-band optical (SDSS $g^{\prime }$, $r^{\prime }$ and $i^{\prime }$) imaging of a narrow strip ($\sim 22^{\prime }$) of sky utilizing the time-delayed integration technique. Single-scan ILMT images have an integration time of 102s and consecutive-night images can be co-added to further improve the signal-to-noise ratio. An image subtraction technique will also be applied to the nightly recorded observations in order to detect transients, objects exhibiting variations in flux or position. Presently, the facility is in the commissioning phase and regular operation will commence in March 2023. This paper presents a discussion of the main preparation activities before first light, along with preliminary results obtained.

Extreme weather and climate events including extreme precipitation have increased in frequency, intensity, and severity due to climate change and hit vulnerable communities disproportionately hard. However, there is a gap in the understanding of the characteristics of extreme precipitation and their effects on socio-economic activities in sub-Saharan Africa societies. The study utilized climate hazards group infrared precipitation with station data (CHIRPS) to analyze the climate characteristics from 1981 to 2019 over Senegal, Burkina Faso, Tanzania, and Malawi. Standardized precipitation evapotranspiration index (SPEI) and standardized precipitation index (SPI) were used to classify the precipitation and water balance anomalies with respect to the long-term observations. It was found that Burkina Faso and Senegal have a similar climate signal with more rainfall in Burkina Faso. Malawi recorded more rainfall than Tanzania. All the four countries recorded a high rainfall variability of extreme events. Standardized hydro climatic indices have shown that these sub-Saharan countries have suffered severe droughts which have negatively affected the socio-economic activities among the rural populations.

H.E.S.S., a system of imaging Cherenkov telescopes, is dedicated to the observation of TeV gamma-rays. Within the first years of operation a number of objects were detected, most of these objects were previously not known to be TeV emitters. The observed TeV emission is crucial for the understanding of particle acceleration in the sources.

Here I will review the results obtained on Galactic sources expected to show variable emission. Variable emission was detected with high significance from the binary systems PSR B1259−63 / SS 2883 and LS5039. The emission of the latter object appears to be periodic in accordance with the orbit. No pulsed emission from pulsars was detected so far. For three pulsars (PSR B0531+21, PSR B0833−45, PSR B1706−44) upper limits on the TeV emission at the EGRET pulse phases were derived.

In dermatology, the optical coherence tomography (OCT) is used to visualize the skin over few millimeters depth. These images are affected by speckle, which can alter their interpretation, but which also carries information that characterizes locally the visualized tissue. In this paper, we propose to differentiate the skin layers by modeling locally the speckle in OCT images. The performances of four probability density functions (Rayleigh, Lognormal, Nakagami and Generalized Gamma) to model the distribution of speckle in each skin layer are analyzed. From this study, we propose to classify the pixels of OCT images using the estimated parameters of the most appropriate distribution. Quantitative results with 30 images are compared to the manual delineations of five experts. The results confirm the potential of the method to generate useful data for robust segmentation.