1,161 research outputs found
A new procedure for monitoring the range and standard deviation of a quality characteristic
The Shewhart and the Bonferroni-adjustment R and S chart are usually applied to monitor the range and the standard deviation of a quality characteristic. These charts are used to recognize the process variability of a quality characteristic. The control limits of these charts are constructed on the assumption that the population follows approximately the normal distribution with the standard deviation parameter known or unknown. In this article, we establish two new charts based approximately on the normal distribution. The constant values needed to construct the new control limits are dependent on the sample group size (k) and the sample subgroup size (n). Additionally, the unknown standard deviation for the proposed approaches is estimated by a uniformly minimum variance unbiased estimator (UMVUE). This estimator has variance less than that of the estimator used in the Shewhart and Bonferroni approach. The proposed approaches in the case of the unknown standard deviation, give out-of-control average run length slightly less than the Shewhart approach and considerably less than the Bonferroni-adjustment approach.Shewhart, Bonferroni-adjustment, Average run length, R chart, S chart
Transfer Learning for Inverse Design of Tunable Graphene-Based Metasurfaces
This paper outlines a new approach to designing tunable electromagnetic (EM)
graphene-based metasurfaces using convolutional neural networks (CNNs). EM
metasurfaces have previously been used to manipulate EM waves by adjusting the
local phase of subwavelength elements within the wavelength scale, resulting in
a variety of intriguing devices. However, the majority of these devices have
only been capable of performing a single function, making it difficult to
achieve multiple functionalities in a single design. Graphene, as an active
material, offers unique properties, such as tunability, making it an excellent
candidate for achieving tunable metasurfaces. The proposed procedure involves
using two CNNs to design the passive structure of the graphene metasurfaces and
predict the chemical potentials required for tunable responses. The CNNs are
trained using transfer learning, which significantly reduced the time required
to collect the training dataset. The proposed inverse design methodology
demonstrates excellent performance in designing reconfigurable EM metasurfaces,
which can be tuned to produce multiple functions, making it highly valuable for
various applications. The results indicate that the proposed approach is
efficient and accurate and provides a promising method for designing
reconfigurable intelligent surfaces for future wireless communication systems
Wireless power and data transmission to high-performance implantable medical devices
Novel techniques for high-performance wireless power transmission and data interfacing with implantable medical devices (IMDs) were proposed. Several system- and circuit-level techniques were developed towards the design of a novel wireless data and power transmission link for a multi-channel inductively-powered wireless implantable neural-recording and stimulation system. Such wireless data and power transmission techniques have promising prospects for use in IMDs such as biosensors and neural recording/stimulation devices, neural interfacing experiments in enriched environments, radio-frequency identification (RFID), smartcards, near-field communication (NFC), wireless sensors, and charging mobile devices and electric vehicles. The contributions in wireless power transfer are the development of an RFID-based closed-loop power transmission system, a high-performance 3-coil link with optimal design procedure, circuit-based theoretical foundation for magnetic-resonance-based power transmission using multiple coils, a figure-of-merit for designing high-performance inductive links, a low-power and adaptive power management and data transceiver ASIC to be used as a general-purpose power module for wireless electrophysiology experiments, and a Q-modulated inductive link for automatic load matching. In wireless data transfer, the contributions are the development of a new modulation technique called pulse-delay modulation for low-power and wideband near-field data communication and a pulse-width-modulation impulse-radio ultra-wideband transceiver for low-power and wideband far-field data transmission.Ph.D
Investigating and analyzing the impact of IC on the profitability of companies listed on the Iraqi stock exchange
Companies need to follow a continual strategy of knowledge improvement and innovation to maintain their competitive advantage in the face of rapid technological advances and global competition. This method, known as intellectual capital (IC), aids businesses in keeping their edge in the market. Managers should pay attention to IC because of this reason. This study looked at how IC affected the bottom line of a company listed on the ISE in Iraq. The study studied data from a subset of the ISE-listed manufacturers throughout the span of ten years, from 2010 to 2019. Multivariate regression, as well as the F-Limer, Chow, and Hausman tests, were used to examine the data. It was shown that IC improved both ROA and ROE. The results also showed that the capital added value coefficient (COAV) positively impacted ROA but had no discernible impact on ROE. Moreover, ROA and ROE were found to be positively impacted by structural capital's coefficient of added value COAV. And while it had little impact on ROA, the added value coefficient (AVC) of human capital (HC) had a positive and large impact on ROE
Finite Element Analysis of Flush End Plate Moment Connections under Cyclic Loading
This paper explains the results of an investigation on the analysis of flush end plate steel connections by means of finite element method. Flush end plates are a highly indeterminate type of connection, which have a number of parameters that effect their behavior. Because of this, experimental investigations are complicated and very costly. Today, the finite element method provides an ideal method for analyzing complicated structures. Finite element models of these types of connections under monotonic loading have previously been investigated. A numerical model, which can predict the cyclic behavior of these connections, is of critical importance, as dynamic experiments are more costly. This paper summarizes a study to develop a three-dimensional finite element model that can accurately capture the cyclic behavior of flush end plate connections. Comparisons between FEM results and experimental results obtained from full-scale tests have been carried out, which confirms the accuracy of the finite element model. Consequently, design equations for this connection have been investigated and it is shown that these predictions are not precise in all cases. The effect of end plate thickness and bolt diameter on the overall behavior of this connection is discussed. This research demonstrates that using the appropriate configuration, this connection has the potential to form a plastic hinge in the beam--desirable in seismic behavior
Assessment of check dams’ role in flood hazard mapping in a semi-arid environment
This study aimed to examine flood hazard zoning and assess the role of check dams as effective hydraulic structures in reducing flood hazards. To this end, factors associated with topographic, hydrologic and human characteristics were used to develop indices for flood mapping and assessment. These indices and their components were weighed for flood hazard zoning using two methods: (i) a multi-criterion decision-making model in fuzzy logic and (ii) entropy weight. After preparing the flood hazard map by using the above indices and methods, the characteristics of the change‐point were used to assess the role of the check dams in reducing flood risk. The method was used in the Ilanlu catchment, located in the northwest of Hamadan province, Iran, where it is prone to frequent flood events. The results showed that the area of ‘very low’, ‘low’ and ‘moderate’ flood hazard zones increased from about 2.2% to 7.3%, 8.6% to 19.6% and 22.7% to 31.2% after the construction of check dams, respectively. Moreover, the area of ‘high’ and ‘very high’ flood hazard zones decreased from 39.8% to 29.6%, and 26.7% to 12.2%, respectively
Influence of Olive Cultivar on Oil Attributes in the Arid Region of Qom, Iran
Olive cultivation has economic and health implications. The quality of harvested oil is affected by the type of cultivar and the climate in which the trees are cultivated. This study was carried out to determine quality indices (peroxide value, K232, and K270), fatty acid composition, and pigment profiles in some cultivars grown in an arid region in central Iran. These are cultivated in completely different climatic conditions than the major olive growing areas of Iran. The results have illustrated that there are significant differences between the cultivars in oil quality, pigments content, and fatty acid composition. Oil quality of all studied cultivars falls within the established ranges for extra virgin olive oil. Oleic acid levels of the ‘Beledy’ and ‘Leccino’ cultivars are below the International Olive Council (IOC) established limit. Oils of the ‘Mari’, ‘Koroneiki’, and ‘Mission’ cultivars had the highest monounsaturated fatty acids (MUFA) content. However, polyunsaturated fatty acid (PUFA) content for Mission oil was considerably higher than ‘Koroneiki’ and ‘Mari’ oils. The ratio of MUFA/PUFA for ‘Mari’ and ‘Koroneiki’ was higher among all the cultivars studied. Furthermore, these two cultivars presented higher oleic/linoleic acid ratio and lower Cox values. Based on our findings, ‘Mari’ and ‘Koroneiki’ are among the best performing cultivars for producing olive oil in intensely hot and arid regions
A New Procedure to Monitor the Mean of a Quality Characteristic
The Shewhart, Bonferroni-adjustment and analysis of means (ANOM) control chart are typically applied to monitor the mean of a quality characteristic. The Shewhart and Bonferroni procedure are utilized to recognize special causes in production process, where the control limits are constructed by assuming normal distribution for known parameters (mean and standard deviation), and approximately normal distribution regarding to unknown parameters. The ANOM method is an alternative to the analysis of variance method. It can be used to establish the mean control charts by applying equicorrelated multivariate non-central t distribution. In this paper, we establish new control charts, in phases I and II monitoring, based on normal and t distributions having as a cause a known (or unknown) parameter (standard deviation). Our proposed methods are at least as effective as the classical Shewhart methods and have some advantages
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