A Computational Approach for Human-like Motion Generation in Upper Limb Exoskeletons Supporting Scapulohumeral Rhythms

This paper proposes a computational approach for generation of reference path for upper-limb exoskeletons considering the scapulohumeral rhythms of the shoulder. The proposed method can be used in upper-limb exoskeletons with 3 Degrees of Freedom (DoF) in shoulder and 1 DoF in elbow, which are capable of supporting shoulder girdle. The developed computational method is based on Central Nervous System (CNS) governing rules. Existing computational reference generation methods are based on the assumption of fixed shoulder center during motions. This assumption can be considered valid for reaching movements with limited range of motion (RoM). However, most upper limb motions such as Activities of Daily Living (ADL) include large scale inward and outward reaching motions, during which the center of shoulder joint moves significantly. The proposed method generates the reference motion based on a simple model of human arm and a transformation can be used to map the developed motion for other exoskeleton with different kinematics. Comparison of the model outputs with experimental results of healthy subjects performing ADL, show that the proposed model is able to reproduce human-like motions.Comment: In 2017 IEEE International Symposium on Wearable & Rehabilitation Robotics (WeRob2017

The Effect of Mechanical and Geometric Parameters on the Shear and Axial Failures of Columns in Reinforced Concrete Frames

Experimental research activities and post-earthquake considerations have demonstrated that reinforcedconcrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure duringearthquakes. According to this point by using failure limit curve, we can assess the effective parameters in shearand axial failure of reinforced concrete columns in framed buildings. In the current study by flexural, shear andaxial springs which are used in series, shear and axial failures and important effective parameters have beenassessed, Besides 5,10 and 15 story models with different amounts of initial axial load ratio have been analyzedby nonlinear push-over analysis. The results of analytical models contain behavior of buildings based on differentinitial axial load ratio and different spacing of transverse reinforcement are compare

Evaluating the effect of security on tourists' loyalty to the destination with emphasis on the mediating role of satisfaction and destination image (Case study: Shiraz foreign tourists)

Objective: One of the most important factors that can affect the loyalty of tourists is the security of the destination. Accordingly, the main purpose of this study is to investigate the effect of security on the loyalty of foreign tourists in Shiraz with the mediating role of satisfaction and destination image. Methods: The present research is applied in terms of purpose and is descriptive and survey based on the nature and method. Research data were collected in the field through a questionnaire. The statistical population of the study is foreign tourists visiting the city of Shiraz in 2019. The sample size was estimated to be equal to 200 tourists according to the Cochran’s formula and a simple random method was used to distribute the questionnaire. Data collected based on descriptive and inferential statistics methods have been analyzed. Results: The results showed that Security with a coefficient of 0.20 directly and with a coefficient of 0.07 with the mediating role of the destination image and with a coefficient of 0.26 with the mediating role of satisfaction has a positive effect on the loyalty of foreign tourists in Shiraz. The overall effect of security on the loyalty of foreign tourists is equal to 0.53. Conclusion: With the increase in the level of security and the improvement of this factor in the city of Shiraz, we will see an increase in the loyalty of foreign tourists to this city, which will lead to the further prosperity of the tourism industry of this city

Induced voltage in piezoelectric tube driven segments and their use in nanopositioning, an assessment

A piezoelectric tube actuator has a number of segments or electrodes. The induced voltage and the piezoelectric voltage, two easy-to-measure electrical signals in piezoelectric tubes, have been used in position estimation of these actuators since 2006 and 1982. However, since introduction, the in-duced voltage has never been compared with the piezoelectric voltage for piezoelectric tubes’ po-sition estimation. In addition, only linear models have been used to present the relationship between the induced voltage and the position of piezoelectric tubes. In other words, in the literature, it has been practically assumed that (1) the relationship between the induced voltage and the position is linear, and (2) the induced voltage can estimate the position more accurately compared to the piezoelectric voltage. This article assesses and nullifies both these assumptions. In this research, with the use of the experimental data, both aforementioned voltage signals were mapped into the position through linear and nonlinear models. It was shown that the position can be estimated less accurately with the induced voltage compared to the piezoelectric voltage, and the relationship of the position with the induced voltage presents higher and non-negligible nonlinearity compared to the one with the piezoelectric voltag

Global burden of chronic respiratory diseases and risk factors, 1990–2019: an update from the Global Burden of Disease Study 2019

Background: Updated data on chronic respiratory diseases (CRDs) are vital in their prevention, control, and treatment in the path to achieving the third UN Sustainable Development Goals (SDGs), a one-third reduction in premature mortality from non-communicable diseases by 2030. We provided global, regional, and national estimates of the burden of CRDs and their attributable risks from 1990 to 2019. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated mortality, years lived with disability, years of life lost, disability-adjusted life years (DALYs), prevalence, and incidence of CRDs, i.e. chronic obstructive pulmonary disease (COPD), asthma, pneumoconiosis, interstitial lung disease and pulmonary sarcoidosis, and other CRDs, from 1990 to 2019 by sex, age, region, and Socio-demographic Index (SDI) in 204 countries and territories. Deaths and DALYs from CRDs attributable to each risk factor were estimated according to relative risks, risk exposure, and the theoretical minimum risk exposure level input. Findings: In 2019, CRDs were the third leading cause of death responsible for 4.0 million deaths (95% uncertainty interval 3.6–4.3) with a prevalence of 454.6 million cases (417.4–499.1) globally. While the total deaths and prevalence of CRDs have increased by 28.5% and 39.8%, the age-standardised rates have dropped by 41.7% and 16.9% from 1990 to 2019, respectively. COPD, with 212.3 million (200.4–225.1) prevalent cases, was the primary cause of deaths from CRDs, accounting for 3.3 million (2.9–3.6) deaths. With 262.4 million (224.1–309.5) prevalent cases, asthma had the highest prevalence among CRDs. The age-standardised rates of all burden measures of COPD, asthma, and pneumoconiosis have reduced globally from 1990 to 2019. Nevertheless, the age-standardised rates of incidence and prevalence of interstitial lung disease and pulmonary sarcoidosis have increased throughout this period. Low- and low-middle SDI countries had the highest age-standardised death and DALYs rates while the high SDI quintile had the highest prevalence rate of CRDs. The highest deaths and DALYs from CRDs were attributed to smoking globally, followed by air pollution and occupational risks. Non-optimal temperature and high body-mass index were additional risk factors for COPD and asthma, respectively. Interpretation: Albeit the age-standardised prevalence, death, and DALYs rates of CRDs have decreased, they still cause a substantial burden and deaths worldwide. The high death and DALYs rates in low and low-middle SDI countries highlights the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for tobacco control, enhancing air quality, reducing occupational hazards, and fostering clean cooking fuels are crucial steps in reducing the burden of CRDs, especially in low- and lower-middle income countries

Burden of tracheal, bronchus, and lung cancer in North Africa and Middle East countries, 1990 to 2019: Results from the GBD study 2019

ObjectiveTo provide estimates on the regional and national burden of tracheal, bronchus, and lung (TBL) cancer and its attributable risk factors from 1990 to 2019 in the North Africa and Middle East (NAME) region.Methods and materialsThe Global Burden of Disease (GBD) 2019 data were used. Disability-adjusted life years (DALYs), death, incidence, and prevalence rates were categorized by sex and age groups in the NAME region, in 21 countries, from 1990 to 2019. Decomposition analysis was performed to calculate the proportion of responsible factors in the emergence of new cases. Data are presented as point estimates with their 95% uncertainty intervals (UIs).ResultsIn the NAME region, TBL cancer caused 15,396 and 57,114 deaths in women and men, respectively, in 2019. The age-standardized incidence rate (ASIR) increased by 0.7% (95% UI -20.6 to 24.1) and reached 16.8 per 100,000 (14.9 to 19.0) in 2019. All the age-standardized indices had a decreasing trend in men and an increasing trend in women from 1990 to 2019. Turkey (34.9 per 100,000 [27.6 to 43.5]) and Sudan (8.0 per 100,000 [5.2 to 12.5]) had the highest and lowest age-standardized prevalence rates (ASPRs) in 2019, respectively. The highest and lowest absolute slopes of change in ASPR, from 1990 to 2019, were seen in Bahrain (-50.0% (-63.6 to -31.7)) and the United Arab Emirates (-1.2% (-34.1 to 53.8)), respectively. The number of deaths attributable to risk factors was 58,816 (51,709 to 67,323) in 2019 and increased by 136.5%. Decomposition analysis showed that population growth and age structure change positively contributed to new incident cases. More than 80% of DALYs could be decreased by controlling risk factors, particularly tobacco use.ConclusionThe incidence, prevalence, and DALY rates of TBL cancer increased, and the death rate remained unchanged from 1990 to 2019. All the indices and contribution of risk factors decreased in men but increased in women. Tobacco is still the leading risk factor. Early diagnosis and tobacco cessation policies should be improved

Feature extraction using wavelet analysis with application to machine fault diagnosis

Two different approaches have been used to diagnose faults in machinery such as internal combustion engines. In the first approach, a mathematical model of the specific engine or component under investigation is developed and a search for causes of change in engine performance is conducted based on the observations made in the system output. In the second approach, the specific engine or component is considered a black box. Then, by observing some sensory data, such as cylinder pressure, cylinder block vibrations, exhaust gas temperatures, and acoustic emissions, and analyzing them, fault(s) can be traced and detected. In this research the latter approach is employed in which vibration data is used for the detection of malfunctions in reciprocating internal combustion engines. The objective of this thesis is to develop effective data-driven methodologies for fault detection and diagnosis. The main application is the detection and characterization of combustion related faults in reciprocating engines; faults such as knock, improper ignition timing, loose intake and exhaust valves, and improper valve clearances. To perform fault diagnosis in internal combustion engines, cylinder head vibration data are used for characterizing the underlying mechanical and combustion processes. Fault diagnosis includes two main stages: feature extraction and classification. In the feature extraction stage, we have utilized wavelets for the analysis of acceleration data acquired at the cylinder head to capture meaningful features that include necessary information about the state of the engine. Wavelets have shown to provide suitable signal processing means for analysis of transient data and noise reduction. Wavelet packets, as a generalization of wavelets, offer even a more powerful data analysis structure to extract features that are capable of identifying combustion malfunctions. Various concepts of wavelets, wavelet packets, related algorithms and assessment techniques have been reviewed, analyzed and discussed. As a result of this research, a novel methodology for fault diagnosis has been developed. This has been achieved through critically investigating available methodologies employed in fault diagnosis and classification, and by understanding their shortcomings. The developed method not only avoids the demerits of the previous techniques, but also demonstrates superior performance. To compare the performance of the proposed approach with major existing methods, various sets of real-world machine data acquired by mounting accelerometer sensors on the cylinder head, as well as a set of synthetic data, have been extensively tested.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat