Topic Review
Human Activity Recognition in Telemedicine
Telemedicine has the potential to improve access and delivery of healthcare to diverse and aging populations. Recent advances in technology allow for remote monitoring of physiological measures such as heart rate, oxygen saturation, blood glucose, and blood pressure. However, the ability to accurately detect falls and monitor physical activity remotely without invading privacy or remembering to wear a costly device remains an ongoing concern. Human activity involves a series of actions carried out by one or more individuals to perform an action or task, such as sitting, lying, walking, standing, and falling. The field of human activity recognition (HAR) has made remarkable advancements. The primary objective of HAR is to discern a user’s behavior, enabling computing systems to accurately classify and measure human activity.
  • 118.2K
  • 15 Jan 2024
Topic Review
Ammonia Production
Ammonia is the second-largest global chemical products, utilized as agricultural fertilizer, food production, industrial materials, refrigerants, and additives. Recently, the utilization of ammonia as the energy carrier (secondary energy source) has attracted many interests, due to its high volumetric hydrogen density, low storage pressure, high stability for long-term storage, high auto-ignition temperature, low condensation pressure, and lower gas density than air. in general, ammonia production includes the currently adopted thermochemical (Haber–Bosch), electrochemical, and photochemical cycle processes. 
  • 58.3K
  • 20 May 2022
Topic Review
Path Planning and Optimization Techniques
The optimization algorithms for pathfinding for ground robotics [20,21,22,23,24], aerial vehicles [25,26,27], and underwater vehicles [28,29] includes a wide range of applications. The most well-known applications for autonomous vehicles are obstacle avoidance, path planning, localization, navigation, sensing, and communication, which works on pre-essential maps related to the environment; they also play a vital role in communication relay, aviation industry for surveillance, and loitering dominated missions. 
  • 52.8K
  • 09 Oct 2021
Topic Review
BMW 3 Series (E46)
The BMW E46 is the fourth generation of the BMW 3 Series, which was produced from 1997 to 2006. The body styles of the range are: All-wheel drive, last available in the E30 3 Series, was reintroduced for the E46 on the 325xi, 330xi and 330xd models. The E46 was the first 3 Series to be available with an engine using Valvetronic (variable valve lift). Various electronic features were also introduced to the 3 Series in the E46 generation, including satellite navigation, electronic brake-force distribution, rain-sensing wipers and LED tail-lights. Following the introduction of the E90 3 Series sedans in late 2004, the E46 began to be phased out. However the E46 coupé and convertible body styles remained in production until 2006. The E46 M3 is powered by the S54 straight-six engine with either a 6-speed manual or a 6-speed SMG-II transmission. The M3 was introduced in late 2000 and was produced in coupé and convertible body styles only.
  • 42.6K
  • 03 Nov 2022
Topic Review
Applications of Wireless Sensor Networks
A Wireless Sensor Network (WSN) is a group of spatially dispersed sensor nodes, which are interconnected by using wireless communication. The purpose of this entry is to provide an up-to-date presentation of both traditional and most recent applications of WSNs and hopefully not only enable the comprehension of this scientific area but also facilitate the perception of novel applications.
  • 39.5K
  • 28 Mar 2022
Topic Review
Space Vector PWM Techniques
This entry elaborates the basic concept of space vector Pulse Width modulation technique for a three-phase voltage source inverter. Why space vector Pulse width modulation (PWM) is required and how it is implemented in the simulation model, is described in the entry.  A number of PWM scheme is used to obtain variable voltage and frequency supply from a power converter. The most widely used PWM schemes for three-phase voltage source inverter (VSI) are carrier-based sinusoidal PWM and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization and better dc bus utilization. This entry focuses on step by step development of MATLAB/SIMULINK model of SVPWM. Firstly the model of a three-phase VSI is discussed based on space vector representation. Next simulation model of SVPWM is obtained using MATLAB/SIMULINK. Simulation results are also provided. 
  • 34.8K
  • 16 Jun 2022
Topic Review
Damping Ratio
Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in biological systems and bikes. The damping ratio is a dimensionless measure describing how oscillations in a system decay after a disturbance. Many systems exhibit oscillatory behavior when they are disturbed from their position of static equilibrium. A mass suspended from a spring, for example, might, if pulled and released, bounce up and down. On each bounce, the system tends to return to its equilibrium position, but overshoots it. Sometimes losses (e.g. frictional) damp the system and can cause the oscillations to gradually decay in amplitude towards zero or attenuate. The damping ratio is a measure describing how rapidly the oscillations decay from one bounce to the next. The damping ratio is a system parameter, denoted by ζ (zeta), that can vary from undamped (ζ = 0), underdamped (ζ < 1) through critically damped (ζ = 1) to overdamped (ζ > 1). The behaviour of oscillating systems is often of interest in a diverse range of disciplines that include control engineering, chemical engineering, mechanical engineering, structural engineering, and electrical engineering. The physical quantity that is oscillating varies greatly, and could be the swaying of a tall building in the wind, or the speed of an electric motor, but a normalised, or non-dimensionalised approach can be convenient in describing common aspects of behavior.
  • 34.7K
  • 12 Oct 2022
Topic Review Video
Modular Multilevel Converters
A modular multilevel converter (MMC) is an advanced voltage source converter applicable to a wide range of medium and high-voltage applications. It has competitive advantages such as quality output performance, high modularity, simple scalability, and low voltage and current rating demand for the power switches. The generalized configuration of a three-phase MMC is comprised of a DC terminal, an AC terminal, and a converting kernel involving three phase legs. Each leg/phase has two symmetric arms referred to as the upper arm and lower arm. The upper arm and lower arm contain a group of identical submodules connected in series together with a chock inductor to suppress high-frequency components in the arm current.  The research interests of MMCs are primarily associated with the topologies, mathematical modeling, output voltage and current control, submodule balancing control, circulating current control, and modulation methods. And the incorporation of wideband gap (WBG) semiconductors are prospected to facilitate the MMC application with further advantages of high-voltage and high-power operations, low power losses, high efficiency, improved reliability, and reduced module size and cooling system.
  • 21.2K
  • 18 Aug 2021
Topic Review
Night Vision Device
A night vision device (NVD), also known as night optical/observation device (NOD) and night vision goggles (NVG), is an optoelectronic device that allows images to be produced in levels of light approaching total darkness. The image may be a conversion to visible light of both visible light and near-infrared, while by convention detection of thermal infrared is denoted thermal imaging. The image produced is typically monochrome, e.g. shades of green. NVDs are most often used by the military and law enforcement agencies, but are available to civilian users. The term usually refers to a complete unit, including an image intensifier tube, a protective and generally water-resistant housing, and some type of mounting system. Many NVDs also include optical components such as a sacrificial lens, or telescopic lenses or mirrors. An NVD may have an IR illuminator, making it an active as opposed to passive night vision device. Night vision devices were first used in World War II and came into wide use during the Vietnam War. The technology has evolved greatly since their introduction, leading to several "generations" of night vision equipment with performance increasing and price decreasing. Consequently, they are available for a wide range of applications, e.g. for gunners, drivers and aviators.
  • 20.5K
  • 13 Oct 2022
Topic Review
Free-Space Path Loss
In telecommunication, the free-space path loss (FSPL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle free, line-of-sight path through free space (usually air). The "Standard Definitions of Terms for Antennas", IEEE Std 145-1993, defines "free-space loss" as "The loss between two isotropic radiators in free space, expressed as a power ratio." It does not include any power loss in the antennas themselves due to imperfections such as resistance. Free space loss increases with the square of distance between the antennas because the radio waves spread out due the inverse square law and decreases with the square of the wavelength of the radio waves. The FSPL is rarely used standalone, but rather as a part of the Friis transmission formula, which includes the gain of antennas. It is a factor that must be included in the power link budget of a radio communication system, to ensure that sufficient radio power reaches the receiver that the transmitted signal is received intelligibly.
  • 20.5K
  • 02 Jun 2023
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