Miracle-dz/UniFAR-FTUs huggingface dataset:
Opto-mechanical performances of slewing mirror space telescope for GRB detection

The UFFO (Ultra-Fast Flash Observatory) Pathfinder is a space instrument onboard the Lomonosov satellite scheduled to be launched in November 2011. It is designed for extremely fast observation of optical counterparts of Gamma Ray Bursts (GRBs). It consists of two subsystems; i) UBAT (UFFO Burst Alert & Trigger Telescope) and ii) SMT (Slewing Mirror Telescope). This study is concerned with SMT opto-mechanical subsystem design and optical performance test. SMT is a F/11.4 Ritchey-Chretien type telescope benefited from compact design with a short optical tube assembly for the given focal length of 1,140 mm. SMT is designed to operate over a wide range of wavelength between 200 nm and 650 nm and has 17 arcmin FOV (Field of View), providing 4 arcsec in detector pixel resolution. The main detector is 256 x 256 ICCD (Intensified Charge-Coupled Device) of 22. 2μm in pixel size. This SMT design offers good imaging performance including 0.77 in MTF at Nyquist frequency of 22.52 /mm and 2.7 μm in RMS spot radius. The primary (M1) and secondary (M2) mirror are hyperbolic surfaces and were manufactured within 1/50 waves (He-Ne, 632.8nm) in RMS surface error. After completion of the initial integration, the SMT opto-mechanical subsystem reached to the system wavefront error better than 1/10 waves in room temperature. We then tested the opto-mechanical performances under thermal cycling and vibration. In this study, we report the SMT subsystem design solution and integration together with thermal and vibration test results.
A STUDENT PROGRAM RECOMMENDATION SYSTEM PROTOTYPE

Recommendation systems have emerged as a useful e-commerce tool to assist customers in making purchases based on similarities and preferences of others. However, their potential has not been highly utilized to help in one area that could assist both professors and students - student advising. Using a recommender system has potential risks such as lower student retention if the system makes poor recommendations but it also has the potential of helping to guide potential students to a wider range of majors and courses that they may not have otherwise considered. This paper discusses a prototype recommender system for advising preapplicants on probable courses of study at a university.
Probe of pulse amplitude of electromagnetic field for investigation of GPR antenna performance

In this report universal probe of electromagnetic field amplitude is described. The probe is intended for measurements of GPR antenna radiation in upper hemisphere as well as under ground surface. Goedbloed (1991) and de Jongh (1998) used analogous probe for measuring GPR antenna radiation pattern in lower hemisphere. The method described there is not flexible enough and narrows the range of measured parameters (depth of probe is fixed). Here we propose universal EM field probe and method for its use. Such sensor may also be used for in situ measurements of main parameters of sounded ground: (Gamma) 0 -- linear absorption and (nu) -- EM wave propagation velocity in ground. Example of such probe use is given below.
Dynamic VAr sources scheduling for improving voltage stability margin

This paper presents a methodology to be added at the power system dispatch problem in order to evaluate and improve voltage stability margin by optimizing generators and synchronous condensers reactive power injection. The main objective is to reschedule the reactive injection of the machines, from a perspective of improving voltage stability margin, without impact on the active economical dispatch.
Research on Key Technology of Airport Simulation Based on OSG

To build airport simulation system, several key techniques must be solved. Thus the Real-time and Practicality of the system can be enhanced, and a strong feeling of immersion can be given. This paper deeply gives research on the key techniques of sky simulation, rain and snow effect simulation, telescope simulation and multi-channel in the airport simulation system, and gives the implementation.
Large-scale metal additive manufacturing: a holistic review of the state of the art and challenges

Additive Manufacturing (AM) has the potential to completely reshape the manufacturing space by removing the geometrical constraints of commercial manufacturing and reducing component lead time, especially for large-scale parts. Coupling robotic systems with direct energy deposition (DED) additive manufacturing techniques allow for support-free printing of parts where part sizes are scalable from sub-metre to multi-metre sizes. This paper offers a holistic review of large-scale robotic additive manufacturing, beginning with an introduction to AM, followed by different DED techniques, the compatible materials and their typical as-built microstructures. Next, the multitude of robotic build platforms that extend the deposition from the standard 2.5 degrees of freedom (DOF) to 6 and 8 DOF is discussed. With this context, the decomposition and slicing of the computerized model will be described, and the challenges of planning the deposition trajectory will be discussed. The different modalities to monitor and control the deposition in an attempt to meet the geometrical and performance specifications are outlined and discussed. A wide range of metals and alloys have been reported and evaluated for large-scale AM parts. These include steels, Ti, Al, Mg, Cu, Ni, Co–Cr and W alloys. Different post-processing steps, including heat treatments, are discussed, along with their microstructures. This paper finally addresses the authors' perspective on the future of the field and the largest knowledge gaps that need to be filled before the commercial implementation of robotic AM.
A three-phase version of the hybridge rectifier associated to the three-phase ZVS DC/DC converter with asymmetrical duty cycle

This paper proposes the use of a three-phase version of the hybridge rectifier in the three-phase ZVS DC/DC converter with asymmetrical duty cycle. The use of this new rectifier improves significantly the efficiency of the converter because only three diodes are responsible for the connection losses in the secondary side. Besides, the current in the secondary side of the transformer is half of the output current. In addition, all the advantages obtained in the three phase dc/dc converter, i.e. the increase of the frequency of the output and input currents, the improved distribution of the losses as well as the soft commutation for a wide load range, are preserved. Then, the resulting topology is viable to achieve high efficiency and high power density at high power levels. The theoretical analysis, simulation and experimental results obtained with a prototype of 6 kW, as well as the comparison of the efficiency with the full bridge rectifier are presented.
Battery electrochemical nonlinear/dynamic SPICE model

An integrated battery model has been produced which accurately represents DC nonlinear battery behavior together with transient dynamics. The NiH/sub 2/ battery model begins with a given continuous-function electrochemical math model. The math model for the battery consists of the sum of two electrochemical process DC currents, which are a function of the battery terminal voltage. This paper describes procedures for realizing a voltage-source SPICE model which implements the electrochemical equations using behavioral sources. The model merges the essentially DC nonlinear behavior of the electrochemical model, together with the empirical AC dynamic terminal impedance from measured data. Thus the model integrates the short-term linear impedance behavior, with the long-term nonlinear DC resistance behavior. The long-duration non-Faradaic capacitive behavior of the battery is represented by a time constant. Outputs of the model include battery voltage/current, state-of-charge, and charge-current efficiency.
Design, development and characterization of an x-band 5 bit DMTL phase shifter using an inline MEMS bridge and MAM capacitors

A radio frequency micro-electro-mechanical system (RF-MEMS) 5 bit phase shifter based on a distributed MEMS transmission line concept with excellent phase accuracy and good repeatability is presented in this paper. The phase shifter is built with three fixed–fixed beams; one is switchable with electrostatic actuation and the other two are fixed for a metal–air–metal (MAM) capacitor. The design is based on a coplanar waveguide (CPW) configuration using alumina substrate. Gold-based surface micromachining is used to develop the individual primary phase bits (11.25°/22.5°/45°/90°/180°), which are fundamental building blocks of the complete 5 bit phase shifter. All of the primary phase bits are cascaded together to build the complete phase shifter. Detailed design methodology and performance analysis of the unit cell phase shifter has been carried out with structural and parametric optimization using an in-line bridge and MAM capacitors. The mechanical, electrical, transient, intermodulation distortion (IMD), temperature distribution, power handling and loss performances of the MEMS bridge have been experimentally obtained and validated using simulations up to reasonable extent. A single unit cell is able to provide 31 dB return loss, maximum insertion loss of 0.085 dB and a differential phase shift of 5.95° (at 10 GHz) over the band of interest. Furthermore, all primary phase bits are individually tested to ensure overall optimum phase shifter performance. The complete 5 bit phase shifter demonstrates an average insertion loss of 4.72 dB with return loss of better than 12 dB within 8–12 GHz using periodic placement of 62 unit cells and a maximum phase error of ±3.2° has been obtained at 10 GHz. Finally, the x-band 5 bit phase shifter is compared with the present state-of-the-art. The performance of the 5 bit phase shifter when mounted inside a test jig has been experimentally investigated and the results are presented. The total area of the phase shifter is 19.4 mm2. To the best of our knowledge, this is the first reported digital distributed MEMS transmission line type RF-MEMS phase shifter that has undergone different reliability stages.
An alternative layout for CPW‐fed printed antennas with low back radiation

In this paper, we analyze a patch fed by a hybrid system microstrip‐coplanar waveguide. The proposed feeding structure allows us to design an antenna with a significant reduction of the back‐radiation especially in the broadside direction. The analysis is made using the MPIE formulation of the method of moments (MoM). © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 481–483, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10796
Direct Water Injection to Improve Diesel Spray Combustion

Now, it is essential to apply some measures for NOx reduction to low-speed diesel engines emitting much more NOx than high-speed engines. At the same time PM emission must be reduced especially when bunker fuel or heavy fuel is burned. This paper describes the applications of SFWI (Stratified Fuel Water Injection) system and DWI (Direct Water Injection) system to large sized diesel engines to reduce NOx and PM emission. SFWI system makes it possible to inject water during fuel injection from the same nozzle hole without mixing the liquids. DWI system injects water with high injection pressure from the other injection hole than the fuel injection hole into the combustion chamber directly. For testing both the systems, a 2-stroke-cycle low-speed test engine was used.Copyright © 2003 by ASME
Infrastructure for the design and fabrication of MEMS for RF/microwave and millimeter wave applications

This article describes and provides valuable information for companies and universities with strategies to start fabricating MEMS for RF/Microwave and millimeter wave applications. The present work shows the infrastructure developed for RF/Microwave and millimeter wave MEMS platforms, which helps the identification, evaluation and selection of design tools and fabrication foundries taking into account packaging and testing. The selected and implemented simple infrastructure models, based on surface and bulk micromachining, yield inexpensive and innovative approaches for distributed choices of MEMS operating tools. With different educational or industrial institution needs, these models may be modified for specific resource changes using a careful analyzed iteration process. The inputs of the project are evaluation selection criteria and information sources such as financial, technical, availability, accessibility, simplicity, versatility and practical considerations. The outputs of the project are the selection of different MEMS design tools or software (solid modeling, electrostatic/electromagnetic and others, compatible with existing standard RF/Microwave design tools) and different MEMS manufacturing foundries. Typical RF/Microwave and millimeter wave MEMS solutions are introduced on the platform during the evaluation and development phases of the project for the validation of realistic results and operational decision making choices. The encountered challenges during the investigation and the development steps are identified and the dynamic behavior of the infrastructure is emphasized. The inputs (resources) and the outputs (demonstrated solutions) are presented in tables and flow chart mode diagrams.
Transfer or Emergence: Strategies for Building Design Knowledge Through Knowledge Transfer Partnerships

The business of design is clearly a knowledge-based activity. Governments have introduced a variety of mechanisms to support knowledge transfer. One approach in the UK is the Knowledge Transfer Partnership (KTP) programme, which supports collaboration between universities and businesses. This paper reflects on experiences of running design-related KTP programmes. Firstly, examples of KTP programmes with companies that were inexperienced in using design are reviewed. These KTP programmes have concentrated on transferring knowledge of tools, techniques and processes. Recent experience of a KTP programme with a company partner that is highly experienced in design is then examined. This KTP programme has been based on creating tools within the company partner through codifying existing tacit knowledge. Reflection on both approaches suggests that attention needs to be paid to the types of knowledge that might be involved in design-related KTPs. The paper concludes by suggesting ways of structuring KTP programmes to support tacit knowledge emergence.
A non‐baseline algorithm for damage locating in flexural structures using dynamic distributed macro‐strain responses

The concept of distributed strain‐sensing techniques has been proposed in our recent research, which was dedicated to utilizing the strain distributions throughout the full or partial areas of structures to detect arbitrary and unforeseen damage. An algorithm not requiring a detailed analytical model is presented for damage locating in flexural structures through the direct use of dynamic responses recorded by distributed long‐gauge strain sensors. The modal macro‐strain vector (MMSV), which has been proven to have a mapping relation with displacement mode shape, can be extracted directly from macro‐strain time‐series data, from which a damage evaluating index can be derived and used as an indicator for locating damage. Numerical examples are simulated to verify the sensitivity and effectiveness of the index in different cases. Furthermore, experimental investigations on a cantilevered beam with various long‐gauge fibre optic sensors placements are carried out to examine the feasibility and applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization and optimization of infrared poly SiGe bolometers

In this paper, we present a complete characterization of poly SiGe bolometers. Devices having different dimensions and different geometry have been fabricated. The dependence of the low-frequency noise and of the temperature coefficient of resistance (TCR) on resistivity in poly SiGe has been measured and modeled. The impact of resistivity, bias voltage, thermal conductance, thickness, and dimensions of the active element on the device performance has been investigated. It has been demonstrated that, by using the appropriate absorber and by optimizing the device parameters, poly SiGe bolometers are suitable for realizing high-performance focal plane arrays (FPA's).
Spatial ability and its implication for novice architecture students

Constructive perception ability that combines perception, conception and spatial reasoning composed of visual analysis, synthesis and representation in iterative nature can be argued to be equally related to creative design ability. One of the more important aptitudes for students studying Architecture design is spatial ability, often referred to as simply visual perception. Spatial ability encompasses the mental manipulative skills required to perform mental processes such as the rotation of objects, the understanding of how objects appear in different positions, and the conceptualisation of how objects relate to each other in space. The relationship between various cognitive abilities and design creativity is a necessary consideration for Architecture education. Spatial ability is a construct generally considered to comprise of several spatial factors called elements or components where each measures a separate spatial skill. Literature has reported that there is a relationship between the spatial ability of students and their success in certain types of subjects, e.g. technical drawing. However, there are not a large number studies that have focused on the relationship between spatial ability and design-based courses which are prevalent in the Architecture discipline. This paper reports on a research project concerned with the assessment of spatial ability specific to design disciplines, Architecture being a primary design discipline studied. The project measured spatial performance using an online 3D ability test (3DAT) that was developed in accordance with psychometric test development procedures and properties such as reliability and validity for the 3DAT are above acceptable standards. The 3DAT measures choice accuracy and reaction times across a range of abilities that were expected to exist for design students. The spatial performance of students was compared to their results on a number of design projects in a first year design studio to establish if there was a positive relationship between their spatial ability and their performance in a course focused on design. Conference theme: Design education
Times Semi-Passive RFID Tags with Double Loop Antennas Arranged as a Shifted Gate Stability Optimization

In this article, Very Crucial subject discussed in Semi-Passive RFID TAGs system stability. Semi-Passive TAGs with double loop antennas arranged as a shifted gate system stability optimization under delayed electromagnetic interferences. The double loop antenna is employed due to the fact that this antenna consists of two parallel loops; i.e., primary and secondary loops. We define V i1 (t) and V i2 (t) as the voltages in time on double loop antennas. V i1 (t) is the voltage in time on the primary loop and V i2 (t) is the voltage in time on the secondary loop. The index (i) stand for the first gate (i=1) and second gate (i=2). Due to electromagnetic interferences there are different in time delays respect to gate antenna's first and second loop voltages and voltages derivatives. The delayed voltages are V i1 (t-τ 1 ) and V i2 (t-τ 2 ) respectively (τ 1 ≠ τ 2 ) and delayed voltages derivatives are dV i1 (t-Δ 1 )/dt, dV i2 (t-Δ 2 )/dt respectively.
Ecological Momentary Assessment of Physical Activity and Wellness Behaviors in College Students Throughout a School Year: Longitudinal Naturalistic Study

Background The Wellness Environment app study is a longitudinal study focused on promoting health in college students. Objective The two aims of this study were (1) to assess physical activity (PA) variation across the days of the week and throughout the academic year and (2) to explore the correlates that were associated with PA, concurrently and longitudinally. Methods The participants were asked to report their wellness and risk behaviors on a 14-item daily survey through a smartphone app. Each student was provided an Apple Watch to track their real time PA. Data were collected from 805 college students from Sept 2017 to early May 2018. PA patterns across the days of the week and throughout the academic year were summarized. Concurrent associations of daily steps with wellness or risk behavior were tested in the general linear mixed-effects model. The longitudinal, reciprocal association between daily steps and health or risk behaviors were tested with cross-lagged analysis. Results Female college students were significantly more active than male ones. The students were significantly more active during the weekday than weekend. Temporal patterns also revealed that the students were less active during Thanksgiving, winter, and spring breaks. Strong concurrent positive correlations were found between higher PA and self-reported happy mood, 8+ hours of sleep, ≥1 fruit and vegetable consumption, ≥4 bottles of water intake, and ≤2 hours of screen time (P<.001). Similar longitudinal associations found that the previous day’s wellness behaviors independently predicted the following day’s higher PA except for mood. Conversely, the higher previous-day PA levels were associated with better mood, more fruit and vegetable consumption, and playing less music, but with higher liquor consumption the next day. Conclusions This study provides a comprehensive surveillance of longitudinal PA patterns and their independent association with a variety of wellness and risk behaviors in college students.
Beyond Distance Decay: Discover Homophily in Spatially Embedded Social Networks

Existing studies suggest distance decay as an important geographic property of online social networks. Namely, social interactions are more likely to occur among people who are closer in physical space. Limited effort has been devoted so far, however, to quantifying the impact of homophily forces on social network structures. In this study, we provide a quantitative understanding of the joint impact of geographic distance and people’s socioeconomic characteristics on their interaction patterns. By coupling large-scale mobile phone, income, and housing price data sets in Singapore, we reconstruct a spatially embedded social network that captures the cell phone communications of millions of phone users in the city. By associating phone users with their estimated residence, we introduce two indicators (communication intensity and friendship probability) to examine the cell phone interactions among places with various housing price values. Our findings suggest that, after controlling for distance, similar places tend to have relatively higher communication intensity than dissimilar ones, confirming a significant homophily effect as a determinant of communication intensity. When the analysis is focused on the formation of social ties, though, the homophily effect is more nuanced. It persists at relatively short distances, whereas at higher distances a tendency to form ties with people in the highest social classes prevails. Overall, the results reported in this study have implications for understanding social segregation in cities. In particular, the physical separation of social groups in a city (e.g., residential segregation) will have a direct impact on shaping communication or social network segregation. The study highlights the importance of incorporating socioeconomic data into the understanding of spatial social networks.