Engineering

Transforming text into executable code at runtime with a function Eval() in dynamic languages such as PHP and JavaScript provides the ability to programmers to extend applications at any time. But every extensive power comes with a price, and here, performance security and efficiency are the cost. In prior work, we examine reason behind the performance degradation by Eval() calls. But in PHP, Zend compiler has some limitation, and in JavaScript, browser has few limitations. Though the execution of Eval() remains unchanged, we identified few replacements for the same functionality. As few large-scale PHP frameworks have a common pattern of unnecessary use of this dynamic feature, we targeted moodle (a large-scale PHP framework) to prove performance enhancement by replacing Eval’d code with some other programming features. Our static analysis survey reflects that almost 70% Eval’d code is replaceable.

Electronic knees provide a wide range of mobility for the amputees. These can often cover K2 and K3 grades of mobility. To achieve a wider mobility, these electronic knees depend upon feedback sensors which provide real-time data to a microcontroller. Various methods are used to calculate the joint motion and knee angle which include magnetic encoder, electro goniometer, and inertial measurement units. The goal of this paper is to develop a sensor to measure angular change of the “stump” socket using accelerometer and ultimately that of the thigh movement, and to use it as feedback signal to the microcontroller in the electronic knee. Sensing the thigh position directly can help in achieving a more natural gait. This feedback system can be used instead of the passive feedback systems currently used in the electronic knees. Results show the potential of low-cost sensing method as a reliable feedback system which can reduce complexity of the hardware as well as the algorithms currently used in the development of modern electronic knee, and hence the overall cost of the electronic knee.

Prosthetic sockets, after fitting, prevent flow of air around the residual limb. It results in trapping of sweat, creating ideal conditions for bacteria and fungus to thrive. This can lead to skin irritation, abrasion and skin breakdown. Various factors make the stump vulnerable to skin diseases, which can hamper quality of life (QoL) of an amputee. Amputation stump dermatoses (ASD) can occur immediately after socket fitting, or many years after amputation. It has been reported that Amputation stump dermatoses affects 34–78% amputees. Of these ~29% are caused due to mechanically induced stump dermatoses. The design of the stump is a major contributor to stump dermatoses as improper design results in poor fitting, trapping of sweat in closely fitted socket of prosthesis, close contact of materials leading to irritation or an allergy. The high prevalence of stump dermatoses has let to there being a growing importance given to prevention, early management and advanced treatment of skin diseases. The use of new edge technologies in designing the stump socket helps to a greater extent in preventing skin diseases resulting from the above mentioned factors. Biomaterials used in the prosthesis further reduces the risk of these skin diseases. This paper discusses the design techniques and considerations of the stump socket as key measure in prevention of the mechanically induced stump dermatoses.

We present a detailed analysis of the rest-frame optical emission line ratios for three spectroscopically confirmed galaxies at z > 7.5. The galaxies were identified in the James Webb Space Telescope (JWST) Early Release Observations field SMACS J0723.3−7327. By quantitatively comparing Balmer and oxygen line ratios of these galaxies with various low-redshift “analogue” populations (e.g. Green Peas, Blueberries, etc.), we show that no single analogue population captures the diversity of line ratios of all three galaxies observed at z > 7.5. We find that S06355 at z = 7.67 and S10612 at z = 7.66 are similar to local Green Peas and Blueberries. In contrast, S04590 at z = 8.50 appears to be significantly different from the other two galaxies, most resembling extremely low-metallicity systems in the local Universe. Perhaps the most striking spectral feature in S04590 is the curiously high [O III] λ4363/[O III] λ5007 ratio (RO3) of 0.047 (or 0.059 when dust-corrected), implying eit...

Human emotion detection is important to improve the interaction between humans and computers, by allowing computers to tailor their behavior according to the mood of the human operating the computer. In this project, we present a study of various feature extraction methods — Gabor features, Histogram of Gradients, Haar-like features, Moments) coupled with different machine learning algorithms — Support Vector Machines (SVM), Random Trees (aka Random Forests TM ), and Artificial Neural Networks (ANN) to recognize and identify human emotion using facial expressions. We train the classifier on a database of around 10,000 images of 14 subjects emoting Anger, Disgust, Fear, Happiness, Neutral, Sadness, and Surprise. We train and cross validate over these extractorlearner combinations to find the best parameters; and then compare their relative performances. We also conduct experiments to test how accurately humans identify emotion. Our results show that the best performance is obtained u...

Continuous matching of supply and demand through online/real-time decision making is a problem of critical importance in many urban environments. Examples include bike/scooter sharing systems, car sharing, food/ grocery delivery, smart vending machines and other similar aggregation systems. In these systems, apart from supply (e.g., bikes/scooters, cars, restaurants/supermarkets) and demand (e.g., customers), there may also be matching resources that help match supply and demand (e.g., trucks, car drivers, delivery boys). The success of these systems depends on the ability to have supply available at the "right" locations at the "right" time. The matching decisions taken by the company operators are typically performed based on the current status of supply, demand and location of matching resources. In this paper, we present RE-ORG (Repositioning agEnt for Online spatio-tempoRal matchinG problems) to provide guidance for matching resources to have supply at the r...

Continuous matching of supply and demand through online/realtime decision making is a problem of critical importance in many urban environments. [1–4, 7, 9, 10]. Examples include bike/scooter sharing systems, car sharing, food/ grocery delivery, smart vending machines and other similar aggregation systems. In these systems, apart from supply (e.g., bikes/scooters, cars, restaurants/supermarkets) and demand (e.g., customers), there may also be matching resources that help match supply and demand (e.g., trucks, car drivers, delivery boys). The success of these systems depends on the ability to have supply available at the “right" locations at the “right" time. The matching decisions taken by the company operators are typically performed based on the current status of supply, demand and location of matching resources. In this paper, we present REORG (Repositioning agEnt for Online spatio-tempoRal matchinG problems) to provide guidance for matching resources to have supply at ...

(Metamaterials (MTMs) are artificial materials engineered to provide properties like negative permittivity, reversed Doppler Effect, reversed Cherenkov Effect, negative refractive index etc. which “may not be readily available in nature”. The properties like negative permittivity and negative permeability attracts the researchers to study and investigating use of MTMs for designing HPM radiation sources. The sheet beam driven backward-wave oscillators (BWO) using the Cerenkov mechanism is one of the most promising HPM sources due to its high output power and high repetition operations. In the present paper we model the physics of designing a metamaterial based backward wave oscillator as a slow wave structure, driven by an intense sheet electron beam. The dispersion characteristics of the interaction, such as the linear instability growth rate and spatial growth rate, are also analyzed numerically and with PIC simulation.

We use the SPHINX20 cosmological radiation hydrodynamics simulation to study how Lyman continuum (LyC) photons escape from galaxies and the observational signatures of this escape. We define two classes of LyC leaker: Bursty Leakers and Remnant Leakers, based on their star formation rates (SFRs) that are averaged over 10 Myr (SFR10) or 100 Myr (SFR100). Both have $f_{\rm esc}\gt 20{{\ \rm per\ cent}}$ and experienced an extreme burst of star formation, but Bursty Leakers have SFR10 > SFR100, while Remnant Leakers have SFR10 < SFR100. The maximum SFRs in these bursts were typically ∼100 times greater than the SFR of the galaxy prior to the burst, a rare 2σ outlier among the general high-redshift galaxy population. Bursty Leakers are qualitatively similar to ionization-bounded nebulae with holes, exhibiting high ionization parameters and typical H ii region gas densities. Remnant Leakers show properties of density-bounded nebulae, having normal ionization parameters but much low...