Addition is a fundamental function in arithmetic operation; several adder designs have been proposed for implementations in inexact computing. These adders show different operational profiles; some ...of them are approximate in nature while others rely on probabilistic features of nanoscale circuits. However, there has been a lack of appropriate metrics to evaluate the efficacy of various inexact designs. In this paper, new metrics are proposed for evaluating the reliability as well as the power efficiency of approximate and probabilistic adders. Reliability is analyzed using the so-called sequential probability transition matrices (SPTMs). Error distance (ED) is initially defined as the arithmetic distance between an erroneous output and the correct output for a given input. The mean error distance (MED) and normalized error distance (NED) are then proposed as unified figures that consider the averaging effect of multiple inputs and the normalization of multiple-bit adders. It is shown that the MED is an effective metric for measuring the implementation accuracy of a multiple-bit adder and that the NED is a nearly invariant metric independent of the size of an adder. The MED is, therefore, useful in assessing the effectiveness of an approximate or probabilistic adder implementation, while the NED is useful in characterizing the reliability of a specific design. Since inexact adders are often used for saving power, the product of power and NED is further utilized for evaluating the tradeoffs between power consumption and precision. Although illustrated using adders, the proposed metrics are potentially useful in assessing other arithmetic circuit designs for applications of inexact computing.
In metal cutting processes, tool condition monitoring has a great importance to prevent surface damage and maintaining the quality of surface finishing. With the development of digitalisation and ...connection of industrial machines, it has become possible to collect real-time data from various types of sensors (e.g. vibration, acoustic or emission) during the process execution. However, information fusion from multiple sensor signals and tool health prediction still present a big challenge. The aim of this paper is to present a data-driven framework to estimate the tool wear status and predict its remaining useful life by using machine learning techniques. The first part of the framework is dedicated to sensor data preprocessing and feature engineering, while the second part deals with the development of prediction models. Different types of machine learning algorithms are used and compared to find the best result. A case study in a milling process is presented to illustrate the potentialities of the proposed framework for tool condition monitoring.
Neuronal avalanches, measured in vitro and in vivo, exhibit a robust critical behavior. Their temporal organization hides the presence of correlations. Here we present experimental measurements of ...the waiting time distribution between successive avalanches in the rat cortex in vitro. This exhibits a nonmonotonic behavior not usually found in other natural processes. Numerical simulations provide evidence that this behavior is a consequence of the alternation between states of high and low activity, named up and down states, leading to a balance between excitation and inhibition controlled by a single parameter. During these periods, both the single neuron state and the network excitability level, keeping memory of past activity, are tuned by homeostatic mechanisms.
A relationship between an acidic pH in the joints, osteoarthritis (OA), and pain has been previously demonstrated. Acidosis Chemical Exchange Saturation Transfer (acidoCEST) indirectly measures the ...extracellular pH through the assessment of the exchange of protons between amide groups on iodinated contrast agents and bulk water. It is possible to estimate the extracellular pH in the osteoarthritic joint using acidoCEST MRI. However, conventional MR sequences cannot image deep layers of cartilage, meniscus, ligaments, and other musculoskeletal tissues that present with short echo time and fast signal decay. Ultrashort echo time (UTE) MRI, on the other hand, has been used successfully to image those joint tissues. Here, our goal is to compare the pH measured in the knee joints of volunteers without OA and patients with severe OA using acidoCEST-UTE MRI. Patients without knee OA and patients with severe OA were examined using acidoCEST-UTE MRI and the mean pH of cartilage, meniscus, and fluid was calculated. Additionally, the relationship between the pH measurements and the Knee Injury and Osteoarthritis Outcome Score (KOOS) was investigated. AcidoCEST-UTE MRI can detect significant differences in the pH of knee cartilage, meniscus, and fluid between joints without and with OA, with OA showing lower pH values. In addition, symptoms and knee-joint function become worse at lower pH measurements.
Two-Dimensional Schemes for Clocking/Timing of QCA Circuits Vankamamidi, V.; Ottavi, M.; Lombardi, F.
IEEE transactions on computer-aided design of integrated circuits and systems,
2008-Jan., 2008-01-00, 20080101, Volume:
27, Issue:
1
Journal Article
Peer reviewed
At nanoscale, quantum-dot cellular automata (QCA) defines a new device architecture that permits the innovative design of digital systems. Features of these systems are the allowed crossing of signal ...lines with different orientation in polarization on a Cartesian plane, the potential of high throughput due to efficient pipelining, fast signal switching, and propagation. However, QCA designs of even modest complexity suffer from the negative impact due to the placement of long lines of cells among clocking zones, thus resulting in increased delay, slow timing, and sensitivity to thermal fluctuations. In this paper, different schemes for clocking and timing of the QCA systems are proposed; these schemes utilize 2D techniques that permit a reduction in the longest line length in each clocking zone. The proposed clocking schemes utilize logic-propagation techniques that have been developed for systolic arrays. Placement of QCA cells is modified to ensure correct signal generation and timing. The significant reduction in the longest line length permits a fast timing and efficient pipelining to occur while guaranteeing a kink-free behavior in switching.
Abstract Objectives Adipose tissue has been associated with knee osteoarthritis (KOA) pathogenesis, but the longitudinal changes in adipose tissue with KOA progression have not been carefully ...evaluated. This study aimed to determine if longitudinal changes of systemic and local adipose tissue is associated with radiographic progression of KOA. Methods This case-control study used data from the Osteoarthritis Initiative (OAI) and included 315 cases (all the right knees with a minimum of Kellgren-Lawrence score (KL) of 0 and an increase of ≥ 1 KL from baseline to 48 months) and 315 controls matched by age, sex, race, and baseline KL. Cross sectional area of IPFP (IPFP CSA) and subcutaneous adipose tissue around the distal thigh (SCAT thigh) were measured using MRI images at baseline and 24 months. Conditional logistic regression models were fitted to estimate associations of obesity markers, IPFP CSA, and SCAT thigh with radiographic KOA progression. Mediation analysis was used to assess whether IPFP CSA or SCAT thigh mediates the relationships between baseline BMI and radiographic KOA progression. Results 24-month changes of IPFP CSA (ΔIPFP CSA) and SCAT thigh (ΔSCAT thigh ) were significantly greater in cases compared to controls, whereas Δ BMI and Δ abdominal circumference were similar in both groups during follow-up. Adjusted ORs for radiographic KOA progression were 9.299, 95% CI (5.357–16.141) per 1 SD increase of Δ IPFP CSA and 1.646, 95% CI (1.288–2.103) per 1 SD increase of Δ SCAT thigh . ΔIPFP CSA mediated the association between baseline BMI and radiographic KOA progression (87%). Conclusions Subjects with radiographic progression of KOA, had significant increases in IPFP CSA and subcutaneous adipose tissue while BMI and abdominal circumference remained stable. Additional studies are needed to confirm these associations.
Context:
Iodine deficiency disorders are a major public health problem, and programs have been implemented to improve iodine nutrition.
Objective:
The objective of the study was to verify the effects ...of voluntary iodine prophylaxis in a small rural community (Pescopagano, Italy).
Design:
The design of the study was the evaluation of the prevalence of thyroid disorders 15 years after a previous survey conducted before iodine prophylaxis.
Setting:
The setting for this study was a general community survey.
Participants:
One thousand one hundred forty-eight residents were examined in 2010 and 1411 in 1995.
Results:
In 2010, 757 of 1148 subjects (65.9%) routinely used iodized salt, urinary iodine excretion being significantly higher than in 1955 (median 98.0 μg/L, vs 55.0 μg/L, P < .0001). The prevalence of goiter was lower in 2010 than in 1995 (25.8% vs 46.1%, P < .0001), mainly due to the reduction of diffuse goiter (10.3% vs 34.0%, P < .0001). In 2010 vs 1995, thyroid autonomy in subjects younger than 45 years old (3 of 579, 0.5% vs 25 of 1010, 2.5% P = .004) and nonautoimmune hyperthyroidism in subjects older than 45 years old (8 of 569, 1.4% vs 18 of 401, 4.5%, P = .03) were less frequent. The prevalence of hypothyroidism was higher in 2010 vs 1995 (5.0% vs 2.8%, P = .005), mainly because of an increased frequency of subclinical hypothyroidism in subjects younger than 15 years old (7 of 83, 8.4% vs 0 of 419, 0.0%, P < .0001). Accordingly, serum thyroid autoantibodies (19.5% vs 12.6%; P < .0001) and Hashimoto's thyroiditis (14.5% vs 3.5%; P < .0001) were more frequent in 2010 than in 1995.
Conclusions:
In the present work, the role of voluntary iodine prophylaxis was assessed in a small rural community relatively segregated, in which genetic and other environmental factors have not substantially changed between the 2 surveys. Iodine intake strongly affected the pattern of thyroid diseases, but the benefits of correcting iodine deficiency (decreased prevalence of goiter and thyroid autonomy in younger subjects and reduced frequency of nonautoimmune hyperthyroidism in older subjects) far outweighs the risk of development of thyroid autoimmunity and mild hypothyroidism in youngsters.
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