Miracle-dz/UniFAR-FTUs huggingface dataset:
Switchable bandpass filter with two-state frequency responses

A novel switchable bandpass filter with two-state frequency responses is presented, where dual-band bandpass and single bandpass characteristics can be conveniently switched by turning pin diodes on and off. The switchability results from the effect of different working modes. The filter can work as a dual-band bandpass filter obtaining two centre frequencies, 1.8 and 3.5 GHz, which could be appropriately used for GSM and WiMax systems. In the meantime, it also can operate only at 3.5 GHz, rejecting signal at 1.8 GHz. The proposed filter consists of two dual-mode resonators, using pin diodes to switch the frequency responses. An experiment was carried out to validate the design concept, and the measured results agree well with simulated results.
Oil Droplet Impact Dynamics in Aero-Engine Bearing Chambers-Correlations Derived from Direct Numerical Simulations

Bearing Chambers in Aero-Engines are located near the rolling-element type of bearings which support the shafts and accomodate the resulting thrust loads. One of the main task of the bearing chambers is, beside an efficient scavenging of the lubricating oil, the cooling of the hot compartments. A very complex two-phase air-oil flow takes usually place in these bearing chambers consisting of oil droplet-laden air flows and shear-driven liquid wall films. The interaction of the droplets with the wall films is significantly influencing the wall heat transfer and the cooling performance of these systems. For this reason, a detailed characterization and modelling of the mass and momentum exchange between droplets and wall films for the unique impingement parameter range in bearing chambers is inevitable. This scientific report investigates the oil droplet impact dynamics for typical impingement regimes relevant to aero-engine bearing chambers. The application of a Direct Numerical Simulation (DNS) technique based on the Volume-of-Fluid (VOF) method and coupled with a gradient-based adaptive mesh refinement (AMR) technique allowed to characterize the drop impact dynamics during various single micro- and millimeter drop impacts onto thin and thick films. With the help of a special numerical treatment, a self-perturbing mechanism is installed that leads to the correct resolution of the crown disintegration process. The numerical methodology was thoroughly validated using the experimental results of millimeter sized drop impacts onto deep liquid pools. These results were developed with an enhanced back-illuminated high-speed imaging and Particle Tracking Velocimetry (PTV) technique. New insights into the cavity penetration, the crown’s breakup dynamics and the secondary droplet characteristics following a single drop impact have been developed with the help of the isolated variation of different parameters of influence. Particularly the influence of the Froude number, the impingement angle, and the cavity-wall interaction delivered results to date not reported in scientific literature. Beside the advances in fundamental physics describing the drop impact dynamics with the help of the numerical and experimental results, a set of correlations could also be derived. From these correlations, a drop-film interaction model was formulated that is suitable for the parameter range found in bearing chambers.
Understanding and supporting large-scale requirements management

Large market-driven software companies face new challenges in requirements engineering and management that emerged due to their recent extensive growth. At the same time, the pressure generated by competitors’ and users’ expectations demands being more competitive, creative and flexible to more quickly respond to a rapidly changing market situation. In the pursuit of staying competitive in this context, new ideas on how to improve the current software engineering practice are requested to help maintaining the engineering efficiency while coping with growing size and complexity of requirements engineering processes and their products. This thesis focuses on understanding and supporting large-scale requirements management for developing software products to open markets. In particular, this thesis focuses on the following requirements management activities in the mentioned context, namely: scope management, variability management and requirements consolidation. The goals of the research effort in this thesis are to provide effective methods in supporting mentioned requirements management activities in a situation when the size of them and their complexity require large time and skills efforts. Based on empirical research, where both quantitative and qualitative approaches were utilized, this thesis reports on possible improvements for managing variability and presents visualization techniques to assist scope management for large-scale software product development contexts. Both reported ideas are empirically evaluated in case studies in a large-scale context. Additionally, the benefits of using linguistic methods for requirements consolidation are investigated in a replicated experimental study based on a relevant industry scenario.
Calibration and correction of the CCD spectral response nonuniformity for Fourier transform imaging spectrometer

Due to the manufacturing technique, some kinds of CCD, such as the back illuminated CCD, have the problem of spectral response nonuniformity. The near infrared light passing through the substrate and gates and is reflected back into the substrate for a second pass resulting in increased response. For the Fourier transform imaging spectrometer, it adds stripe pattern error to the interferogram and distorts the reconstructed spectrum. The nonuniform response is wavelength dependent due to changes in reflectivity of metal and the cavity formed by silicon and metal with transparent dielectric, so it adds difficulty to the correction of the error of the reconstructed spectrum. In order to reduce the error of the reconstructed spectrum, in this paper, a calibration method and a correction method to correct the error caused by the CCD spectral response nonuniformity was developed, basing on analysis of the property of the CCD spectral response nonuniformity. Firstly, a calibrated monochromater was used to measure the CCD spectral response nonuniformity and the property and affect of the CCD spectral response nonuniformity were analyzed. Method to correct the error of the reconstructed spectrum caused by the stripe pattern error was developed. Secondly, to calibrate the CCD spectral response nonuniformity, the spectral response coefficient and the spatial response nonuniformity coefficient was measured and computed. Finally, we took data with a Fourier transform imaging spectrometer, and got the correction results of the reconstructed spectrums. The results showed that the distortion of recovered spectrum was evidently reduced and the effect of the calibration and correction method was proved.
Improving the quality of indicator systems by MoSi

Long term business success highly depends to how fast a company reacts on changes in the market situation. Those who want to be successful need relevant, up-to-date, and accurate information. Business or economic decisions rely on indicators. One facet of data quality is the integrity of data. Most of the main business and economic indicators suffer from statistical discrepancies. These indicators are based on non-linear equation systems and are normally not crisp, but random due to measurement errors. Consequently, computation of the corresponding probability distributions is usually not trivial. Handling uncertainty within indicator systems is a major challenge for improved decision making. Different approaches exist for dealing with uncertainty, e. g. , Fuzzy set theory and the probabilistic method. The shortcomings of both approaches can be reduced by the use of simulation. As the Gaussian distribution is not closed under all four arithmetic operations, there is the need for Markov Chain Monte Carlo (MCMC) simulation to determine the probability distributions. A combination of data, generated by MCMC simulation, which is based on prior knowledge about a fully specified non-linear, stochastic balance equation system with noisy measurements, is proposed for handling uncertainty within indicator systems. The Metropolis Hastings algorithm enables the use of any computable target probability function. SamPro is the algorithm that implements the MCMC simulation approach for indicator systems. The estimation of unobservable quantities of such models is improved by SamPro and data inconsistencies to the equation system are revealed. MoSi is proposed as a software tool for the modelling of indicator systems as well as their simulation. The implementation of the SamPro algorithm is consequently included in MoSi, as well. MoSi can be used efficiently in the processes of planning, decision making, and controlling.
Active membrane masks for improved overlay performance in proximity lithography

Membrane masks are thin (2 micron x 35 mm x 35 mm) structures that carry the master exposure patterns in proximity (X-ray) lithography. With the continuous drive to the printing of ever-finer features in microelectronics, the reduction of mask-wafer overlay positioning errors by passive rigid body positioning and passive stress control in the mask becomes impractical due to nano and sub-micron scale elastic deformations in the membrane mask. This paper describes the design, mechanics and performance of a system for actively stretching a membrane mask in-plane to control overlay distortion. The method uses thermoelectric heating/cooling elements placed on the mask perimeter. The thermoelectric elements cause controlled thermoelastic deformations in the supporting wafer, which in turn corrects distortions in the membrane mask. Silicon carbide masks are the focus of this study, but the method is believed to be applicable to other mask materials, such as diamond. Experimental and numerical results will be presented, as well as a discussion of the design issues and related design decisions.
Establishing effective, appropriate and applicable technologies in treating contaminated surface water as part of a rehabilitation strategy for the Princess Dump in Roodepoort, west of Johannesburg

This study aimed to identify an effective, appropri ate and applicable technology for the treatment of contaminated surface water from the Princess Dump. Princess Dump is an old abandoned and unrehabilitated gold tailings storage facility situ a ed in Roodepoort, west of Johannesburg. It falls within the Upper Klip River subcatchment, which for ms part of the Klip River catchment. Undoubtedly, abandoned gold tailings storage facili ties have caused varying degrees of environmental damage especially those that have been abandoned an d left unrehabilitated. Water pollution that result from these facilities does not only influence the l ocal environment but also other receptors downstrea m of the source. In order to assess the extent of wat er pollution attributed to the abandoned Princess Dump, sampling was done on specific points around t he s udy site. Other physical and chemical water quality sampling data was obtained from the Departm ent of Water Affairs and Forestry (DWAF). The chemical analysis was performed on the data to dete rmin whether the water quality parameter concentration was within the Target Water Quality R ange (TWQR) as stipulated by DWAF for various uses, while correlation analysis determined the rel ationship between the various water quality parameters at the time of sampling. These analyses gave an indication of the potential liability of th e abandoned Princess Dump as far as the degradation o f the l cal surface water quality. The study identified that pollution resulting from the Princess Dump is seriously impacting on the water quality environment around the site. Differen t surface water treatment systems, active and passive, were reviewed and analysed on the basis of their efficiency and applicability to the site and their ability to remediate the contaminated surface water around the site. This was done in comparison between the various identified systems and their ab ility to treat the contaminated water that is being released from the abandoned site. A preferred water treatment system was identified b ased on its projected efficiency in treating the water quality from the site while considering the w orst case scenario of the pollution. Other potentia l point and non point sources of pollution around the study site were also identified and elaborated on and recommendations made to improve the water quali ty around the site. It was concluded that the local surface water quality has been degraded and t hat a passive surface water treatment technology can adequately improve the water quality before it is released into the environment.
Backlash against the #MeToo movement: How women’s voice causes men to feel victimized

Three studies examined whether perceived increase in women’s “voice” (i.e., being heard and taken seriously about sexual assault) contributes to perceptions of bias against men. In Study 1, both men and women who perceived women to have a greater voice related to sexual assault, perceived greater victimization of men. This relationship was stronger for relatively conservative participants. In Study 2, relatively conservative (but not relatively liberal) participants who read about #MeToo perceived greater men’s victimization than those in the control condition. Study 3 examined responses to perceiving that men are victimized by #MeToo. For relatively conservative (but not liberal) men, perceptions of men’s victimhood led to less willingness to work alone with a woman and less willingness to combat sexual assault (relative to a control condition). Thus, while the #MeToo movement brings awareness of issues of sexual assault, it also generates a backlash among the more conservative, and may accentuate gender disparities.
Electromagnetic Field Analysis of Hybrid Excitation Vehicle Generator with Low Voltage and High Current

In order to further improve the power supply system reliability of low voltage high current vehicle generator, hybrid excitation is used and the permanent magnets are added between the main magnetic poles body and pole shoes. Aiming at reply the problem of limited installation space, the asymmetric pole structure, non-uniform commutating pole, single wave windings playing a role of the pressure line and oblique brush etc are investigated for improving commutation. This paper researched on the distribution of the flux line, the waveform of the air gap magnetic field, and analysis inner magnetic field at the loading by hybrid excitation and no loading by permanent magnet excitation alone respectively with the method of finite element. The results reveal that the magnetic field established by several excitation systems is still symmetric and uniform although the asymmetric structure, so it ensures the provision of suitable medium space for mechanical and electrical energy conversion. By comparing the permanent magnets excitation alone and hybrid excitation in a generator magnetic field distribution and air gap magnetic field waveform, the permanent magnet excitation and electricity excitation realized the superposition of magnetic field, and common establish main generator magnetic field. Hybrid excitation also reduces the current density of excitation coils and improves the heat dissipating performance compared with electrically excited alone. Through the performance analysis of the hybrid excitation, the output voltage waveform is very stable. The curve of auxiliary excitation current along with velocity variation provide important basis for excitation control devices and the development of control algorithm. It will help to improve the stability, reliability and security of the generator, the results can provide key technical support to the development of low-voltage high-current hybrid excitation vehicle generator.
Water Hazard Detection Based on 3D LIDAR

Autonomous off-road navigation is a highly complicated task for a robot or unmanned ground vehicle (UGV) owing to the different kinds of obstacles it could encounter. In-particular, water hazards such as puddles and ponds are very common in outdoor environments and are hard to detect even with ranging devices due to the specular nature of reflection at the air water interface. In recent years, many researches to detect the water bodies have been done. But there still has been very little work on detecting bodies of water that could be navigation hazards, especially at night. In this paper, we used Velodyne HDL-64ES2 3D LIDAR to detect water hazard. The approach first analyzes the data format and transformation of 3D LIDAR, and then writes the data acquisition and visualizations algorithm, integrated data based on ICP algorithm. Finally according the intensity distribution identifies the water hazard. Experiments are carried out on the experimental car in campus, and results show the promising performance.
Digital Educational Platforms: An Emerging School-Family Communication Channel

The establishment of effective communication channels is the basis of building good relations and encourages the participation and involvement of families. In primary schools, there is an increasing need to implement new channels of information and communication with families, as new technologies are a fundamental tool. Furthermore, if we consider the presence of foreign students in the center, this need is even more pressing. A new emerging channel is educational platforms. The focus is on their use as an innovative element in school-family communication and on how to improve family involvement in the school. This paper is framed in the project "cultural diversity and equal opportunities at school" (recercaixa2015 call) and the perceptions and attitudes of teachers and families on educational platforms were explored as a tool for information and communication between school and family. It is based on the results of an ethnography (in-depth interviews and observations) carried out in ten schools in Catalonia with a high percentage of immigration, during the 2017-18 school year. Among the main results, accessibility and ease of use, digital literacy, aptitude, speed of communication, information control, are both weak and strengths points, highlighted by both interlocutors (teachers and family members). In all the schools studied some actions have been implemented to favour their use and eliminate some identified barriers.
Factors influencing online shopping behaviors of Facebook users among undergraduate students in UUM, Sintok, Kedah

Online shopping in Malaysia is a new technology innovation since it has just begun to beating the Malaysia retailing sector with online shopping services. Online buying behavior process discusses about the products bought through online. The process of online buying behavior is kind of similar to traditional shopping behavior except there is no face to face transaction occurred. The aim of this study is to investigate the factors that influencing the online shopping behavior among students. This study is focus on undergraduate students in university Utara Malaysia, Sintok, Kedah who have the Facebook account. A total number of 250 students chosen as respondents but only 168 of them responded to the questionnaire. Statistical Package software for Social Science (SPSS) Version 22.0 was used to analyze the collected data. Reliability analysis, multiple regressions and correlation were applied to this study. The Pearson correlation analysis indicated that perceived risk is a negatively associated with actual online shopping behavior whereas attitude and experience have positive relationship with dependent variable. Furthermore, the multiple regression analysis revealed that all the independent variables have significant prediction on dependent variable. It is suggested for future research to look at the way to influence the attitudes of online buyers among student by investigate some other important factors that able to improve their buying behavior in the future
Reliability Analysis of Phasor Measurement Unit Using Hierarchical Markov Modeling

Abstract The consequence of a phasor measurement unit failure is very severe and may cause a blackout as it is a primary part of a wide-area measurement system. This article presents a hierarchical Markov modeling technique for reliability evaluation of phasor measurement unit. A phasor measurement unit is divided into seven modules for reliability modeling in terms of the functionalities of phasor measurement unit elements. Each module is hierarchically represented using Markov state space models and equivalently converted into two-state Markov representations, such that the reliability of the entire phasor measurement unit can be easily evaluated. The numerical results and sensitivity analyses indicate that the global positioning system module is the most unreliable source of phasor measurement unit, followed by the central processor unit module. The failure rate of the global positioning system receiver (λA) is the most crucial parameter to the phasor measurement unit reliability, followed by the failure rate (λhw) of the hardware in the central processor unit module. Improving the time precision of the crystal oscillator is an effective means to enhance the phasor measurement unit reliability if improving the two key parameters is confined in a manufacturing process.
An Aerodynamic Analysis of a Mixed Flow Turbine

The aerodynamic performance of a high-work Mixed Flow Turbine (MFT) is computed and compared with experimental data. A three dimensional (3-D) viscous analysis is applied to the single stage MFT geometry with a relatively long upstream transition duct. Predicted vane surface static pressures and circumferentially averaged spanwise quantities at stator and rotor exits agree favorably with data. Compared to the results of axisymmetric flow analysis from design intent, the 3-D computation agrees much better especially in the endwall regions where throughflow prediction fails to assess the loss mechanism properly. Potential sources of performance loss such as tip leakage and secondary flows are also properly captured by the analysis.
Use of automatic speech recognition: Current and potential applications

The development of more sophisticated techniques for analysing human speech combined with the increased processing power of microcomputers has resulted in improved performance for machine recognition of human utterances. Consequently, automatic speech recognisers are now either operational or being considered in a variety of industrial tasks, telecommunications, office and aerospace environments, and disabled user applications. However, take-up in two of these application areas, namely, in avionics on the aircraft flight deck, and for disabled users, has been slow. The issues surrounding this state of affairs are briefly discussed in this article, with conclusions being drawn on the way forward for these potential application areas.