Miracle-dz/UniFAR-FTUs huggingface dataset:
DC‐50 GHz RF‐MEMS SPDT switch for high‐reliability applications

A large band SPDT (single‐pole double‐throw) switch based on a very advanced RF‐MEMS switch technology for redundancy schemes are presented. This device allowed to reach state‐of‐the‐art working bandwidth (DC‐50 GHz) and RF performances (IL (Insection loss) < 0.8 dB, isolation > 25 dB, and RL > 20 dB). The 200 mm MEMS technology process has demonstrated a very good stability with very low dispersion (deviations < 0.05 dB for the IL and < 0.6 dB for the isolation over the entire wafer and frequency range). An accurate electrical equivalent circuit, modeling the SPDT in the DC‐65 GHz frequency band, has allowed to extract a contact resistance which is as low as 1.4 Ω. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:333–335, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27330
Linear time-varying identification of ankle mechanical impedance during human walking

This paper presents a new method to investigate the multivariable time-varying behavior of the ankle during human walking, and provides the first experimental results from treadmill walking. A wearable ankle robot with an ensemble-based linear time-varying system identification method enabled identification of transient ankle mechanical impedance in 2 degrees of freedom, both in the sagittal and frontal planes. Several important issues of the ensemble-based identification method in practical measurements are discussed, especially a strategy to solve the limitation of the method which assumes that the system undergoes the same time-varying behavior on every stride. The suggested method was successfully applied to 15 minutes of human walking on a treadmill. Experiments with 10 young healthy subjects showed clear time-varying behavior of ankle impedance across the gait cycle, except the mid-stance phase. Interestingly, most subjects increased ankle impedance just before heel strike in both degrees of freedom. Interpretation of impedance changes was consistent with analysis of electromyographic signals from major muscles related to ankle movements.Copyright © 2012 by ASME
Quality of rainwater harvesting in urban systems: case study in Colombia

An analysis of the utilisation and quality of rainwater in different collection systems located in the Pereira–Dosquebradas (Colombia) conurbation was conducted to evaluate the conditions in these systems and thus determine whether rainwater is safe water for domestic, commercial and industrial purposes. The quality of rainwater and its relation to selected variables (roofing material, material deposits, piping material and amount of precipitation) were evaluated. Six buildings with different types of roofing (zinc, polycarbonate or fibre cement) that have installed systems to capture rainwater were selected for the evaluation. According to the results, the sampled water is suitable for different uses. In cities, rainwater can be adapted and eventually used as an alternative water source, thereby reducing dependence on local and external sources.
Identification of Laminar Composition in Cerebral Cortex Using Low-Resolution Magnetic Resonance Images and Trust Region Optimization Algorithm

Pathological changes in the cortical lamina can cause several mental disorders. Visualization of these changes in vivo would enhance their diagnostics. Recently a framework for visualizing cortical structures by magnetic resonance imaging (MRI) has emerged. This is based on mathematical modeling of multi-component T1 relaxation at the sub-voxel level. This work proposes a new approach for their estimation. The approach is validated using simulated data. Sixteen MRI experiments were carried out on healthy volunteers. A modified echo-planar imaging (EPI) sequence was used to acquire 105 individual volumes. Data simulating the images were created, serving as the ground truth. The model was fitted to the data using a modified Trust Region algorithm. In single voxel experiments, the estimation accuracy of the T1 relaxation times depended on the number of optimization starting points and the level of noise. A single starting point resulted in a mean percentage error (MPE) of 6.1%, while 100 starting points resulted in a perfect fit. The MPE was <5% for the signal-to-noise ratio (SNR) ≥ 38 dB. Concerning multiple voxel experiments, the MPE was <5% for all components. Estimation of T1 relaxation times can be achieved using the modified algorithm with MPE < 5%.
Energetic Electron Precipitation Driven by the Combined Effect of ULF, EMIC, and Whistler Waves

Energetic electron losses in the Earth's inner magnetosphere are dominated by outward radial diffusion and scattering into the atmosphere by various electromagnetic waves. The two most important wave modes responsible for electron scattering are electromagnetic ion cyclotron (EMIC) waves and whistler‐mode waves (whistler waves) that, acting together, can provide rapid electron losses over a wide energy range from few keV to few MeV. Wave‐particle resonant interaction resulting in electron scattering is well described by quasi‐linear diffusion theory using the cold plasma dispersion, whereas the effects of nonlinear resonances and hot plasma dispersion are less well understood. This study aims to examine these effects and estimate their significance for a particular event during which both wave modes are quasi‐periodically modulated by ultra‐low‐frequency (ULF) compressional waves. Such modulation of EMIC and whistler wave amplitudes provides a unique opportunity to compare nonlinear resonant scattering (important for the most intense waves) with quasi‐linear diffusion (dominant for low‐intensity waves). The same modulation of plasma properties allows better characterization of hot plasma effects on the EMIC wave dispersion. Although hot plasma effects significantly increase the minimum resonant energy, Emin, for the most intense EMIC waves, such effects become negligible for the higher frequency part of the hydrogen‐band EMIC wave spectrum. Nonlinear phase trapping of 300–500 keV electrons through resonances with whistler waves may accelerate and make them resonant with EMIC waves that, in turn, quickly scatter those electrons into the loss‐cone. Our results highlight the importance of nonlinear effects for simulations of energetic electron fluxes in the inner magnetosphere.
The E-Commerce System and its Evaluation of Manufacturing

In this paper, Electronic commerce (e-commerce) systems application of manufacturing industry is summaried; e-commerce system of manufacturing is introduced. Efforts to develop measures the success of e-commerce system of manufacturing have been hampered by many obstacles. The purpose of this study is to develop a comprehensive model and instrument for measuring e-commerce systems of manufacturing with user satisfaction as one of the antecedents. Also, based on the analysis of features and users’ behavior change of manufacturing e-commerce systems, the basic indexes of systems success measures of e-commerce manufacturing were constructed. Also we integrated the basic indexes into a structural model of systems success evaluation of Chinese e-commerce manufacturing. Furthermore, the method is put forward to analyze the mutual influence relationship of the indexes. The work of this paper is of important meaning to manufacturing companies and e-commerce systems success researchers both in realism and academic study.
Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO2 and CH4

When organic matter from thawed permafrost is released, the sources and sinks of greenhouse gases (GHGs), like carbon dioxide (CO2) and methane (CH4) in Arctic rivers will be influenced in the future. However, the temporal variation, environmental controls, and magnitude of the Arctic riverine GHGs are largely unknown. We measured in situ high temporal resolution concentrations of CO2, CH4, and oxygen (O2) in the Ambolikha River in northeast Siberia between late June and early August 2019. During this period, the largely supersaturated riverine CO2 and CH4 concentrations decreased steadily by 90% and 78%, respectively, while the O2 concentrations increased by 22% and were driven by the decreasing water temperature. Estimated gas fluxes indicate that during late June 2019, significant emissions of CO2 and CH4 were sustained, possibly by external terrestrial sources during flooding, or due to lateral exchange with gas‐rich downstream‐flowing water. In July and early August, the river reversed its flow constantly and limited the water exchange at the site. The composition of dissolved organic matter and microbial communities analyzed in discrete samples also revealed a temporal shift. Furthermore, the cumulative total riverine CO2 emissions (36.8 gC‐CO2 m−2) were nearly five times lower than the CO2 uptake at the adjacent floodplain. Emissions of riverine CH4 (0.21 gC‐CH4 m−2) were 16 times lower than the floodplain CH4 emissions. Our study revealed that the hydraulic connectivity with the land in the late freshet, and reversing flow directions in Arctic streams in summer, regulate riverine carbon replenishment and emissions.
The Interplay Between Hardware and Control System Design in the Development of the Active Rack Isolation System

A primary mission of the International Space Station (ISS) is to provide a premier microgravity laboratory environment for conducting acceleration sensitive scientific research. In order to accomplish this goal, vibroacoustic disturbances caused by station activities that occur during the microgravity mode of operation, must be controlled. In addition to source isolation and other passive isolation methods, the ISS uses active isolation at the receiver, through the use of an Active Rack Isolation System (ARIS), as part of its overall vibration isolation strategy. A schematic diagram of a typical ARIS payload rack is shown. The ARIS isolation control system senses rack acceleration via three triaxial accelerometer heads and uses eight pushrod actuators to perform active vibration attenuation. Position sensors housed in the actuator assembly are used to sense the relative position between the rack and the station. Electrical power, data and other essential resources are routed through a set of umbilicals that interface with a passthrough panel at the bottom of the rack. A representative umbilical set is shown.
Direction of arrival estimation for uncorrelated and coherent signals with uniform linear array

A novel direction of arrival (DOA) estimation method is proposed with uniform linear array when uncorrelated and coherent signals coexist. The DOAs of uncorrelated signals are first estimated using a new method of modified total least squares estimation of signal parameters via rotation invariance techniques. Afterwards, the contributions of uncorrelated signals are eliminated and a new matrix is constructed based on the spatial difference matrix. Then, the coherent signals can be resolved by performing the forward spatial smoothing scheme on the new matrix. The proposed method can resolve more signals than the array elements with good performance. Simulation results demonstrate the effectiveness and efficiency of the proposed method.
Velocity scheduled driver assisted control

This paper investigates the effectiveness of velocity-scheduled Driver Assisted Control (DAC) to control the yaw rate of a front wheel drive, four-wheel steer passenger vehicle. The goal of this research is to be able to impart new handling characteristics to a vehicle through the entire range of operational longitudinal velocities. The DAC uses vehicle yaw rate as input and the rear steering angle as output, thus allowing the driver to maintain a direct line of vehicle control via the front wheels for safety reasons. Multiple DAC controllers are designed for discrete longitudinal velocities within the vehicle's operating range. A transition methodology was then implemented to switch between DAC controllers as the longitudinal velocity changes. Finally, the controller was tested experimentally on a scaled vehicle testbed.
A Uni-Planar Fed 2-D Slot Array for Digital Beamforming

A compact design of two-dimensional (2-D) antenna array for digital beamforming is proposed in this paper. The essential idea is based on switchable microstrip slot antennas in conjunction with spatial multiplexing of local elements (SMILE) techniques. The SMILE technique makes it possible to realize a series-fed digital-beamforming (DBF) antenna array in one dimension and leaves room for parallel element in the other dimension. This provides a simple way of constructing 2-D DBF arrays with a simple and uni-planar feed network. It also offers other advantages such as low cost and compatibility with MMICs for the receiver system. A 4x4 receiving array test-bed at 5.5GHz operating frequency is fabricated and digital beamforming on this test-bed is successfully demonstrated in the E- and H- planes. Index Terms — Compact array, digital-beamforming, slot antennas, SMILE (Spatial Multiplexing of Local Elements).
Data Repair Method for Real Time Urban Link Speed Estimation

Real-time link speed estimation plays an important role in Intelligent Transportation Systems. Recently, traffic data is gradually being collected by probe vehicles such as taxis equipped with global positioning system (GPS) receivers. The number of probe vehicles may vary with time on the road. This creates a problem that the accuracy of link speed may decline sharply if there is not enough GPS data. The aim of this research is to propose a new method for repairing link speed data when there is an insufficient number of a probe vehicle using a Back Propagation Neural Network (BPNN) for this purpose. According to the number of probe vehicles, a self-adaptive filter is designed to merge the measured value and the predicted value. An arterial road in Guangzhou city was selected as a case study to test the proposed method. The performance test illustrates that the proposed method provides significantly better results than a normal speed estimation method.
Damage Patterns from Satellite Images of the 2003 Bam, Iran, Earthquake

High-resolution (0.6m) commercial satellite images contain a wealth of information for mapping earthquake damage. Satellite images of the city of Bam, acquired on 30 September 2003 (pre-earthquake) and 03 January 2004 (post-earthquake), were obtained and used to distinguish damage patterns across the city. Comparisons between pre- and post-earthquake images clearly show structural damage and collapse. Using spectral (color) and textural information from the post-earthquake image, regions of damage were identified using a semi-automated computer-based algorithm. This analysis indicates that the damage within the city of Bam was concentrated in the eastern sections of the city. The extent of damage in some sections of the city reached 100%. The results from this study not only provide information regarding damage patterns for the city of Bam, but they also illustrate the potential for using satellite images to understand and document earthquake effects during future earthquakes.
A wideband mixer designed with low conversion loss through the entire W-band

In this paper, a mixer is designed with low conversion loss through the entire W-band. A novel low pass filter is proposed and used to select the intermediate frequency signal with large rejection of the local oscillator (LO) and radio frequency (RF) signals. A single slot is added on the LO passage to achieve impedance matching in a narrow frequency band, while two slots and one metal strip are added on the RF passage to achieve impedance matching in a wide frequency band. The detailed design process is presented, where a more accurate full-wave simulation model of the adopted diode is suggested. Difference in performances can be obtained by changing the key sizes of the matching structures. One sample is fabricated, and the measured conversion loss is less than 9.5 dB through the entire W-band (from 75 to 110 GHz) under fixed LO condition. The measured return loss of RF port is between 5 and 13.5 dB.
Uma Ferramenta para Modelagem de Processos de Negócios com base em Padrões de Recomendação

A Notação de Modelagem de Processos de Negócios (BPMN) é a especificação desenvolvida pela OMG para representar processos de negócios no paradigma de modelagem imperativa. A criação de diagramas BPMN continua sendo uma atividade dependente do desempenho humano e do conhecimento do domínio da aplicação. Nesse contexto, este trabalho propõe uma ferramenta de apoio à modelagem de processos baseada no conceito de Padrão de Recomendação com o objetivo de gerar recomendações posicionais em um processo interativo integrado à atividade de modelagem. O estudo de caso mostra que cada recomendação sugerida é sensível ao estado atual do modelo. O modelo final é sintático e semanticamente correto.
Combating amyloid-induced cellular toxicity and stiffness by designer peptidomimetics

Amyloid beta (Aβ) aggregation species-associated cellular stress instigates cytotoxicity and adverse cellular stiffness in neuronal cells. The study and modulation of these adverse effects demand immediate attention to tackle Alzheimer's disease (AD). We present a de novo design, synthesis and evaluation of Aβ14-23 peptidomimetics with cyclic dipeptide (CDP) units at defined positions. Our study identified AkdNMC with CDP units at the middle, N- and C-termini as a potent candidate to understand and ameliorate Aβ aggregation-induced cellular toxicity and adverse stiffness.
Charting presence in virtual environments and its effects on performance

Virtual reality (VR) involves an attempt to create an illusion that the user of the VR system is actually present in a synthetic (usually computer-generated) environment. Little is known about how various system parameters affect the illusion of presence in a virtual environment (VE). In particular, there seem to be very little quantitative data on which to base VR system design decisions. Also, while presence (or immersion) in VEs is a primary goal of VR, not much is known about how this variable affects task performance. The goal of this research was to provide a ratio-scale measure of perceived presence in a VE, to explore the effects of a number of environmental parameters on this measure and construct empirical models of these effects, and to relate perceived presence to user performance. This was done by manipulating eleven independent variables in a series of three experiments. The independent variables manipulated were scene update rate, visual display resolution, field of view, sound, textures, head-tracking, stereopsis, virtual personal risk, number of possible interactions, presence of a second user, and environmental detail. Participants performed a set of five tasks in the VE and rated perceived presence at the end of each set using the technique of free-modulus magnitude estimation. The amount of time spent in the VE was also recorded. The results indicate that the VR system parameters manipulated and analyzed in this research did affect participants' subjective feeling of presence in the VE. Field of view, sound, and head-tracking showed the largest effects. Other significant effects found were those of visual display resolution, texture-mapping, stereopsis, and the presence of a second user. Free-modulus magnitude estimation worked well as a measure of perceived presence. A positive relationship was found between perceived presence and task performance, but this relationship was relatively weak. Second-order empirical models were constructed that predicted perceived presence with moderate success and, with less success, task performance.
A V‐band CMOS sub‐harmonic mixer with integrated frequency doubler and 180° out‐of‐phase splitter

A V‐band sub‐harmonic mixer with an integrated frequency doubler and a 180° out‐of‐phase splitter using standard 0.13 μm CMOS technology is reported. The sub‐harmonic mixer comprises a current‐reused bleeding mixer, a baseband amplifier, a 180° (Wilkinson‐power‐divider‐based) out‐of‐phase splitter, and a frequency doubler. The mixer consumed 31.5 mW and achieved input return loss at RF port better than −10 dB for frequencies from 49.8 to 63 GHz. At IF of 20 MHz, the mixer achieved maximum conversion gain of 9.5 dB at RF of 53 GHz. The corresponding 3‐dB bandwidth (ω3dB) of RF is 9.6 GHz (48.4–58 GHz). The measured LO‐to‐RF and LO‐to‐IF isolation were better than 50 dB over the frequency band of interest. In addition, the measured input 1‐dB compression point (P1dB) and input third‐order intermodulation point were −8 dBm and 2.2 dBm, respectively, at RF of 60 GHz. These results demonstrate the proposed mixer architecture is very promising for high‐performance V‐band RFIC applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:870–875, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25888
High linearity 3.0–5.0 GHz ultrawideband CMOS up‐conversion mixer with parallel capacitor

A high linearity CMOS up‐conversion mixer at 3.0–5.0 GHz for ultrawideband applications is presented. The proposed design is implemented in TSMC 0.18‐μm CMOS technology. A Gilbert‐cell active double‐balanced mixer using a capacitor placed in parallel with the intrinsic gate‐source capacitor of a core mixer to improve linearity is used. To further improve the linearity and input matching, source degeneration inductors is used. In addition, a current injection is designed to increase gain and obtain low power. A 100 MHz intermediate frequency input signal is converted to a 3.0–5.0 GHz radio frequency input signal. The measured input third‐order intercept point (IIP3) is 13.5 dBm with a convention gain of 2.3 dB. Moreover, a low power of 7.1‐mWwith a 1.2‐V power supply is obtained. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:427–429, 2015
Accessibility, Vulnerability, and Resilience in a Stochastic Model of Sustainable Ecotourism

We show how the notions of accessibility, vulnerability, and resilience can be used to shed light on the sustainable management of a natural area that is used for ecotourism. To this end, we construct and analyze two queuing-theoretic models that approach the problem of sustainable management in different ways. In the first model, there is a capacity constraint on the number of ecotourists that are permitted to visit the natural area and the optimal rate at which an ecotourist agency manager provides service to the ecotourists is endogenously determined. In the second model, there is no capacity constraint but the manager endogenously ascertains the optimal number of ecotourists who are allowed into the natural area before he provides service to these ecotourists. The sustainability aspect of the management problem is addressed in two ways. First, the conceptualizations of accessibility, vulnerability, and resilience depend on certain long run metrics. Second, the objective functions in the two models that the manager optimizes are formulated using these long run metrics.