Miracle-dz/UniFAR-FTUs huggingface dataset:
Air emissions inventory of the public transport in maracaibo municipality: Part I: Passenger car

The first phase of mobile source emission inventory based on the 2001 census (specifically, passenger car) for the Maracaibo Municipality, is presented in this work. The estimation was carried out using the methodology developed by the U S. EnvironmentaI Protection Agency. The following gases were included in the inventory: carbon monoxide (CO), total hydrocarbons (HC) and nitrogen oxides (NOx). It was verified using the inventory, that the main pollution emitted to the atmosphere was the CO (5307.88 ton/year) representing the 86,42%. folIowed by the HC (6.96%) and NOx (6,62%). In Addition, Maracaibo downtown was the most important area that contributed lo the pollution in the municipality (94.37%). This study is a tool to deve! op a calculus method to evaluate the remaining categories of the public transport, and also for the private sector; provides a methodology for the emission inventory generated by this source, more accurate than the applies in Venezuela and shows the first results to determine the contribution of these gases in the urban environmental pollution and the Heal Island effect.
A Novel Noise Reduction Algorithm of MEMS Gyroscope Based on Compressive Sensing and Lifting Wavelet Transform

A novel noise reduction algorithm combined with compressive sensing (CS) and lifting wavelet transform (LWT) is proposed in this paper. This algorithm can overcome the limitations of traditional noise reduction methods based on Kalman filtering and wavelet threshold filtering. The characteristics of wavelet time-frequency distribution of the microelectromechanical system (MEMS) gyroscope are discussed to illustrate the demerit of the classical filtering methods. Noise reduction algorithm of MEMS gyroscope signal is studied in detail by combining CS theory with lifting wavelet transform. De-noising effect, time-consumption of computation as well as traditional CS reconstruction algorithms are analyzed. The results show that the signal reconstruction algorithm of conventional matching pursuit (MP) greedy algorithms contains more glitches and computation time-consumption, the basis pursuit de-noising (BPDN) algorithm is better and it has advantages of high computational efficiency and ease of implementation.
Gate stack and channel engineering: Study of metal gates and Ge channel devices

The continued scaling of device dimensions in complementary metal oxide semiconductor (CMOS) technology within the sub-100 nm region requires an alternative high dielectric constant (high-κ) oxide layer to counter high tunneling leakage currents, a metallic gate electrode to address polysilicon depletion, boron penetration and high polysilicon sheet resistance, and high mobility channel materials to boost the CMOS performance. Metal gates can also offer improved thermal and chemical stability, but their use requires that we improve our understanding of how the metal alloy phase, crystallographic orientation, and composition affect the electronic properties of the metal alloy-oxide interface. To replace n++ and p++ polysilicon gate electrodes and maintain scaled device performance requires metal gate electrodes with work functions within 0.2 eV of the silicon conduction and valence band edges, i.e., 5.0-5.2 and 4.1-4.3 eV, for PMOS and NMOS devices, respectively. In addition to work function and thermal/chemical stability, metal gates must be integrated into the CMOS process flow. It is the aim of this work to significantly expand our knowledge base in alloys for dual metal gates by carrying out detailed electrical and materials studies of the binary alloy systems of Ru with p-type metal Pt. Three n-type metals systems, Ru-Ta, Ru-Hf and Ru-Nb have also been partially investigated. This work also focuses on high mobility Ge p-MOSFETs for improved CMOS performance. DC magnetron sputtering has been used to deposit binary alloy films on thermally grown SiO2. The composition of the alloy films have been determined by Rutherford backscattering spectrometry and the identification of phases present have been made using x-ray and electron diffraction of samples. The microstructure of the phases of interest has been examined in the
Simulation and performance of a photovoltaic pumping system

An efficient system for pumping water using a brushless DC motor driven by a PV array is described. Development of a system model from the individual component models (array model, motor model and pump model) allows overall system performance to be predicted. Results from the project to date are promising and there is a good correlation between the model and the test results from the system. The system efficiency values, over a range of operating conditions, show a significant improvement over existing systems. <<ETX>>
An isolated full bridge boost converter with active soft switching

The isolated full-bridge boost power converter is attractive in applications such as single-stage power factor correction (PFC) with isolation requirement, or bi-directional DC-DC power converters. It features several merits such as multiple-output capability with one shared choke, single-stage energy processing and good input current shaping ability. But its major disadvantage is that the transformer leakage inductance causes high transient voltage across the bridge switches, which increases the switching rating and decreases the reliability. In this paper, an active soft switching circuit is proposed for the isolated full-bridge boost converter. The proposed soft switching circuit clamps the voltage across the full bridge, transfers the energy in the leakage inductance to the load, and provides zero voltage turn-off for all the main switches. Furthermore, the auxiliary switch features zero current turn-on and zero voltage turn-off. Therefore, the efficiency is improved. The analysis is verified by experimental results.
Simulation Research of the Influence of Random Phase Disturbance on MVDR Beam Former

In practical sonar engineering, the random phase disturbance error will be existed in the output signals of every channels of hydrophone because of the complexity of ocean diffuse environment and the disturbed beam. So only the statistical methods can be used to analyze these errors. By this way, the influence of the different output signals of every channels of hydrophone on MVDR Beam former and the array gain is researched, and also the computer simulation is completed.
Electromagnetic Absorption by the Human Body from 1 - 15 GHz

Microwave radiation is emitted by a wide variety of computing, communications and other technologies. In many transport, industrial and medical contexts, humans are placed in close proximity to several of these sources of emission in reflective, enclosed cavities. Pseudo-reverberant conditions are created, in which absorption by human bodies can form a significant, even the dominant loss mechanism. The amount of energy stored, and hence the field intensities in these environments depend on the nature of electromagnetic absorption by the human body, so quantifying human absorption at these frequencies is necessary for accurate modelling of both electromagnetic interference and communications path loss in such situations. The research presented here aims to quantify absorption by the body, for the purpose of simulating its effect on the environments listed above. For this purpose, nine volunteer participants are enlisted in a preliminary study in which their height and mass are taken and their electromagnetic absorption cross section is measured in a reverberation chamber. The preliminary study is unable to gather enough data to provide precise measurements during the time that a participant is willing to sit motionless in the chamber. Issues also exist due to power loss in some parts of the equipment. A number improvements are made to both the experimental equipment and methodology, and the study is repeated with a sample of 60 adult volunteer participants. The results are compared to the preliminary data and found to match, once unwanted absorption in the latter has been subtracted. The results are also validated using data from absorption by a spherical phantom of known absorptive properties. The absorption cross section of the body is plotted and its behaviour is compared to several biometric parameters, of which the body’s surface area is found to have a dominant effect on absorption. This is then normalised out to give an absorption efficiency of the skin, which is again compared to several biometric parameters; the strongest correlation is found to be with an estimate for average thickness of the subcutaneous fat layer. These data are used to model the effect of 400 passengers on the Q-factor of an airliner’s cabin. Absorption by the passengers is shown to be the dominant loss mechanism in the cabin, showing the importance of accounting for human absorption when modelling electromagnetic propagation and interference in situations that include human occupants. The relationship between subcutaneous fat and absorption efficiency is suggested for further research, as it promises development of new tools to study body composition, with possible medical applications.
Robust and Stable Periodic Flight of Power Generating Kite Systems in Turbulent Wind Flow Field

Abstract Power-generating kite systems extract energy from the wind by periodically pulling a generator on the ground while flying fast in a crosswind direction. Kite systems are intrinsically unstable, and subject to atmospheric turbulences. As an alternative to closed-loop control, this paper investigates the open-loop stabilization and robustification of a kite system using techniques based on the solution of Lyapunov differential equation. A wind flow is computed as a solution to a time-dependent three dimensional Navier-Stokes equation. Open-loop stable trajectories for the power-generating kite system are computed based on the statistical properties of the wind field, and are robustified with respect to the system constraints. The stability and robustness of the resulting trajectories are assessed by simulating the system using the computed time- and space-dependent turbulent wind flow.
Multiple Shaker Random Vibration Control--An Update

The theory of the control of multiple shakers driving a single test item is reviewed. Several improvements that have been introduced since the original papers on the subject will be discussed. The improvements include: (1) specification of the control spectra; (2) the control of non-square systems (the number of shakers does not have to be equal to the number of control points); (3) the connection between sine testing, waveform control, and random control; (4) improvements in feedback control; (5) overlap-add versus time domain randomization; and (6) reproduction of non-Gaussian waveforms.
Economical hand-pushed digital cone penetrometer

A b s t r a c t. The cone penetrometer is widely used in tillage and off-road mobility researches as an indicator of soil strength and density characteristics. Light-weight, manually operated units are especially useful in recording cone index determination at remote field locations. An electronic hand-pushed soil penetrometer with a microcontroller-based data logging system was designed and fabricated to provide a portable penetrometer for determining soil resistance to penetration in tillage studies. The device consists of three main components: a cantilever beam strain-gauge load cell held by housing to measure penetration force, depth measurement mechanism with a photodiode sensor, and a data logging system for amplifying, digitizing, and acquiring data. Data from the data logging system can be downloaded into a personal computer by an RS-232 cable and a software program. In evaluation stage, the performance of the developed penetrometer was compared with an Eijkelkamp hand-pushed digital penetrometer in controlled soil bin conditions. No significant difference was found (p <0.05) between the two penetrometers. The penetrometer performance was reliable and the mechanical and electrical parts worked without any malfunction. The device is very light, easy to use and more economical compared to the conventional types. K e y w o r d s: hand-pushed penetrometer, penetration resistance, load cell, data logging system
Enhanced FAA-Hybrid III dummy for aircraft occupant safety assessment

Following an integral approach unique in aircraft safety, the European HeliSafe project aims to improve the survivability of helicopter crashes and to reduce the risk at injuries for occupants in cockpit and cabin. In the project, a modified FAA-Hybrid III is used for the baseline-, design- and concept validation tests based on helicopter crash scenarios. This paper provides the background to the dummy updates developed and new instrumentation options. Component, sub-assembly and full body tests have been performed to support the development of new dummy parts and to obtain validation data for computer models of the dummy. As illustrated by full-scale cockpit and cabin mock-up crash test results, the enhanced FAA-Hybrid III dummy is a valuable research and certification tool to assess helicopter and aerospace safety.
Multilevel postbuckling design of aerospace structures

Mass minimisation is a key objective in aircraft design, resulting in reduced material costs, fuel consumption and environmental impact. Metals are increasingly being replaced by lightweight composite materials which can be tailored to specific loading requirements. Aircraft wings and fuselages comprise slender stiffened panels which are susceptible to buckling, but advantage can often be taken of a substantial postbuckling reserve of strength. The software VICONOPT [1, 2] performs initial buckling, postbuckling and free vibration analysis of metal or composite stiffened panels, using an exact stiffness formulation and the Wittrick-Williams algorithm [3]. Minimum mass design is achieved by optimising plate widths and layer thicknesses subject to buckling, strength, stiffness and geometric constraints. VICONOPT is a computationally efficient alternative to finite element analysis in the preliminary design of aircraft structures, where many alternative configurations need to be explored. In this context, it is important to note that design changes to individual panels influence the stress distribution over the whole structure, and must also be compatible with the geometry of adjacent panels. VICONOPT MLO [4] is a Visual C++ program providing a multilevel interface between VICONOPT [4] and the finite element software MSC/NASTRAN [5], as illustrated in Fig. 1. At system level, finite element models are constructed using a pre/post-processor such as MSC/PATRAN and analysed using MSC/NASTRAN. Then the model data (i.e. geometry, material properties, stress distributions, etc.) is translated to panel level by VICONOPT MLO, which also requires users to specify the design variables and their bounds. VICONOPT analyses and optimises each of the panels, and the updated geometry is returned to MSC/NASTRAN via VICONOPT MLO. Further finite element analysis of the whole structure determines the new stress distributions in each panel. The process is repeated until a convergence criterion on the overall mass of the structure is met. The present paper extends the procedure by allowing each panel to buckle before the design load is reached [6]. The remaining load is carried under a regime in which the stiffness of the panel is reduced by differing amounts due to the re-distribution of stress among and within the component plates [7]. Fig. 2 plots stress σ against strain e in the postbuckling regime for a square plate of width b loaded in longitudinal compression.
Isolating analog circuits from digital interferences

Recent advances in analog integrated circuit techniques and continued improvement in VLSI technology are enabling more and more mixed-signal analog digital integrated circuits to be implemented on the same chip. One of the important topics in mixed signal circuit design is the coupling of digital switching noise onto sensitive nodes in the analog circuits. In this paper we consider isolating analog circuits using a post processing method. Using an inexpensive mask, a trench can be etched using potassium hydroxide, KOH, from the backside of the wafer all the way to the under-surface of the field oxide. To evaluate the practical aspects of the basic idea, we have implemented some test structures consisting of analog sensing transistors surrounded by conventional guard ring, and large digital inverters a few hundred microns away.
Best-worst scaling: consistency of preferences with discrete choice experiments and stability over time

This paper addresses two research questions regarding best-worst scaling (BWS): (a) Are preferences estimated from BWS tasks consistent with those from discrete choice experiments (DCEs)? and (b) Are population preferences estimated from BWS tasks stable over time? The context of this research was the estimation of a set of preference weights for a number of social care related quality of life indicators, which are used to describe dimensions of people's lives that may be expected to be influenced by social care. This research programme was funded by the UK Department of Health through their HTA programme, and the UK Office for National Statistics through the Treasury's ‘Invest to Save' programme. To address the first question, 300 interviews were undertaken with members of the general public in which they were asked to complete both DCEs and BWS tasks. This approach allowed efficient collection of the data and avoided possible concerns that a matched-sample approach might lead to biases in unobserved characteristics between the groups presented with each preference-elicitation method. The order of the choice tasks was randomised across individuals to avoid bias. The empirical analysis undertaken on the BWS and DCE data revealed that the two methods produced comparable results. Given that the data suggest these methods produce consistent results we can then consider the wider advantages and disadvantages of each method. These are discussed and the decision to take forward and further develop the best-worst scaling task for future phases of the research is explained. The second question, on the stability of preferences, can be addressed from data that we collected in two subsequent phases of data collection using best-worst scaling experiments. In each wave, 500 members of the general public were interviewed to establish their preference weights. These two waves of data collection were undertaken a year apart. Whilst the instrument was subjected to some minor improvements between the two years, this data offers some valuable insights in to the stability of population preferences that have been collected using a best-worst scaling instrument. This paper provides some useful empirical findings on these key questions, although it is acknowledged that the findings may in part be contingent on the context of the study. The paper provides useful insights for other researchers similarly interested in exploring alternative methods available for eliciting data capable of supporting the estimation of discrete choice models for valuation studies and also discusses the benefits that best-worst scaling tasks can provide for some applications.
Information Security on the Web and App Platforms: An Economic and Socio-Behavioral Perspective

Various security measures are ineffective having been designed without adequate usability and economic considerations. The primary objective of this thesis is to add an economic and socio-behavioral perspective to the traditional computer science research in information security. The resulting research is interdisciplinary, and the papers combine different approaches, ranging from analytic modeling to empirical measurements and user studies. Contributing to the fields of usable security and security economics, this thesis fulfills three motivations. First, it provides a realistic game theoretical model for analyzing the dynamics of attack and defense on the Web. Adapted from the classical Colonel Blotto games, our Colonel Blotto Phishing model captures the asymmetric conflict (resource, information, action) between a resource-constrained attacker and a defender. It also factors in the practical scenario where the attacker creates large numbers of phishing websites (endogenous dimensionality), while the defender reactively detects and strives to take them down promptly. Second, the thesis challenges the conventional view that users are always the weakest link or liability in security. It explores the feasibility of leveraging inputs from expert and ordinary users for improving information security. While several potential challenges are identified, we find that community inputs are more comprehensive and relevant than automated assessments. This does not imply that users should be made liable to protect themselves; it demonstrates the potentials of community efforts in complementing conventional security measures. We further analyze the contribution characteristics of serious and casual security volunteers, and suggest ways for improvement. Third, following the rise of third party applications (apps), the thesis explores the security and privacy risks and challenges with both centralized and decentralized app control models. Centralized app control can lead to the risk of central judgment and the risk of habituation, while the increasingly widespread decentralized user-consent permission model also suffers from the lack of effective risk signaling. We find the tendency of popular apps requesting more permissions than average. Compound with the absence of alternative risk signals, users will habitually click through the permission request dialogs. In addition, we find the free apps, apps with mature content, and apps with names mimicking the popular ones, request more permissions than typical. These indicate possible attempts to trick the users into compromising their privacy.
Female Student Participation in Software Engineering Projects: Opportunities to Model Project Evaluation and to Improve Early Prediction of Teamwork Failure

Software engineering project is the preferred mean to measure competency and practical skills among learners in IT-fields. This study investigates the opportunities to model software engineering project final evaluation and improve early prediction of academic software engineering project failure by considering female student participation as a teamwork member, regardless of being a teamwork leader or a teamwork regular member. Four distinct arrangements of software engineering development teamwork are advised and studied. Those arrangements range from female-less participation teamwork to female-dominated participation teamwork. Machine learning techniques are leveraged to build prediction models. Teams are evaluated from two distinct perspectives. First, software products submitted at the end of each project life cycle milestone, namely product perspective. Second, the degree of obeying the good practices of software engineering project development, namely process perspective. Results reveal significant differences due to female student participation. Arrangement of female-less participation attains the worst modeling and prediction performance compared to the other arrangements of female student participation.
L- and S-band 50-watt power GaAs MESFETs

L- and S-band high power GaAs FETs have been developed. At 1.8 GHz, the FET delivers an output power at 1 dB gain-compression point of 42.7 W (46.3 dBm) with 13.3 dB gain and 42% power-added efficiency, and a saturated output power of 51.3 W (47.1 dBm). The developed FETs will contribute to improve the performance of microwave SSPAs used in various radar and communication systems which require higher output power and low distortion.