The article synthesizes and presents the results regarding the stability of positive homogeneous systems that have been researched and published in recent years. Next, we provide a sufficient condition for global exponential stability in the case of discrete-time positive homogeneous systems with an order less than one with time-varying delays.
Abstract The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. In this work, a robust nonlinear controller based on the uncertainty and disturbance estimator (UDE) scheme is successfully developed to tightly regulate the output voltage of the boost converter. A systematic procedure is developed to select the controller gains to achieve a satisfactory output response. Using simulation, the effectiveness of the proposed controller is validated and compared to a recent robust nonlinear controller.
In this paper, we study the coexistence of two key technologies in the same fifth-generation network, namely D2D (Device-to-Device) communication and MEC (Multi-Access Edge Computing) technology. These two promising technologies each have important roles to play in future telecommunications networks. D2D communication is a technology that aims to improve communication efficiency, increase overall throughput, and decrease latency. Multi-Access Edge Computing, a promising new concept, overcomes the burden of core cloud servers. This makes it possible to provide large storage, compute, and resource capacities to mobile edge nodes. With its closest deployment to users, it significantly reduces end-to-end transmission time. Our architecture consists of an access network and a central network, a base station (gNodeB), users, an MEC server and a gateway (UPF) to connect it to the RAN (Radio Access Network) of the core network. The base station controls communication by managing signaling and interference. The MEC server is placed next to the BS to provide data to the devices. It plays the role of the cloud that is located in the core network and allows you to store data and then do calculations for good communication between devices. Finally, we did a simulation using the OMNeT software. The results showed us that the data transmission passed well between the end devices, the antennas and the MEC server with very low latency and reliability.
The present work proposed a simple model for breast cancer hyperthermia treatment at 2.45 GHz. The proposed model involves nine-element antennas alongside a numerical breast comprising multiple tumors. Using a coupled EM-Thermal simulation in the CST suite, the simulated results for a single antenna showed a reflection coefficient (S11) better than -47 dB and demonstrated a bandwidth of 78 MHz. The specific absorption rate (SAR) as a function of input powers was examined inside the breast tissues, where it exhibited a promising performance higher than 3 W/kg at the tumor volume when the applied power was at a reasonable level of 1.5 W whereas it was well attained under the recommend IEEE level of 1.6 W/kg through the surrounded health tissues. Taking into consideration nine-element antennas covering the breast containing two different located tumors, the maximum temperature as a function of treatment time was presented at which a resulting temperature of 43°C was obtainable within 10 minutes, favored for hyperthermia purposes. Considering the maximum power level of 1.5 W, the potential use of applying three-element antennas, simultaneously with 0.5 W, could be achieved.
The present work designed and investigated a 3D basic model for breast cancer detection at the ISM band. The model consists of two multi-slotted rectangular patch antennas and a three-layer breast phantom containing two tumors. A multi-slotted antenna was designed at 2.45 GHz using CST STUDIO SUITE 2018, where the simulated results showed a return loss better than -35 dB and attended more than 77 MHz bandwidth. The diagnosis approach is based on exploiting the electrical properties (frequency dependent) of breast tissues, i.e., mass density, relative permittivity, and conductivity. Once the proposed slotted antenna radiates electromagnetic signals toward the breast model (with and without tumors), the radiation properties in terms of the scattering parameters (S11 and S21), the electrical field, the power flow, the current density, and the power loss density were altered. As a result, the values of these radiation parameters increased when tumors were implanted inside the breast model, informing the presence of cancerous tissues. Moreover, the specific absorption rate (SAR) was estimated as a function of input powers, where the proposed antenna showed a set of low SAR values compared to the IEEE standard of 1.6 W/kg, validating its potential use for diagnosing purposes. The simulated results indicated the prospective use of two slotted antennas (in the first instance) to detect multiple tumors which could be a challenging task using a single-element antenna, where the ultimate goal is to realize a compact antenna array to detect multi-tumors.
This work summarizes the structure and operating features of a high-performance 3-stage dual-delay-path (DDP) voltage-controlled ring oscillator (VCRO) with self-biased delay cells for Phase-Locked Loop (PLL) structurebased clock generation and digital system driving. For a voltage supply VDD = 1.8 V, the resulting set of performance parameters include power consumption PDC = 4.68 mW and phase noise PN@1MHz = -107.8 dBc/Hz. From the trade-off involving PDC and PN, a system level high performance is obtained considering a reference figure-of-merit ( FoM = -224 dBc/Hz ). Implemented at schematic level by applying CMOS-based technology (UMC L180), the proposed VCRO was designed at Cadence environment and optimized at MunEDA WiCkeD tool.
Atomic switches can be used in future nanodevices and to realize conceptually novel electronics in new types of computer architecture because of their simple structure, ease of operation, stability, and reliability.The atomic switch is a single solid-state switch with inherent learning abilities that exhibits various nonlinear behaviors with network devices.However, previous studies focused on experiments and nonvolatile memory applications, and studies on the application of the physical properties of the atomic switch in computing were nonexistent.Therefore, we present a simple behavioral model of a molecular gap-type atomic switch that can be included in a simulator.The model was described by three simple equations that reproduced the bistability using a double-well potential and was able to easily be transferred to a simulator using arbitrary numerical values and be integrated into HSPICE.Simulations using the experimental parameters of the proposed atomic switch agreed with the experimental results.This model will allow circuit designers to explore new architectures, contributing to the development of new computing methods.
Large-scale scientific instruments strongly support top-level research all around the world. Besides their intrinsic merits, they often play a valuable role as pathfinders for developing and testing instrumentation and as training grounds for young researchers. Strategies and roadmaps for these facilities have become a priority for a number of private and public funding organizations. Despite the large amount of mature work done in the industrial arena, it is difficult to find documents providing clear and concise orientation on how to prevent or minimize the damage caused by electrostatic discharges (ESD) in research infrastructure. This paper aims to gather all this information to develop a static charge control plan for a large-scale scientific facility. The specific case of the static charge control plan for the installation of CTA-LST telescopes is added as an example and verification of the actual applicability of the measures proposed in this document, providing static charge in human body monitoring measurements. Specific tests performed on equipment with ESD sensitive components are also described, which helped to assess any possible damage.
DG-MOSFETs are the most widely explored device architectures for nano-scale CMOS circuit design in sub-50 nm due to the improved subthreshold slope and the reduced leakage power compared to bulk MOSFETs.In thin-film (t si < 10 nm) DG-MOS structures, charge carriers are affected by t siinduced quantum confinement along with the confinement caused by a very high electric field at the interface.Therefore, quantum confinement effects on the device characteristics are also quite important and it needs to be incorporated along with short channel effects for nano-scale circuit design.In this paper, we analyzed a DG-MOSFET structure at the 20 nm technology node incorporating quantum confinement effects and various short channel effects.The effect of physical parameter variations on performance characteristics of the device such as threshold voltage, subthreshold slope, I ON -I OFF ratio, DIBL, etc. has been investigated and plotted through extensive TCAD simulations.The physical parameters considered in this paper are operating temperature (T op ), channel doping concentration (N c ), gate oxide thickness (t ox ) and Silicon film thickness (t si ).It was observed that quantum confinement of charge carriers significantly affected the performance characteristics (mostly the subthreshold characteristics) of the device and therefore, it cannot be ignored in the subthreshold region-based circuit design like in many previous research works.The ATLAS TM device simulator has been used in this paper to perform simulation and parameter extraction.The TCAD analysis presented in the manuscript can be incorporated for device modeling and device matching.It can be used to illustrate exact device behavior and for proper device control.
A rigorous full wave technique based on the Transverse Wave Concept Iterative Procedure (WCIP) is used to design a complex Frequency Selective Surface (FSS). These surfaces include a periodically arrangement of identical circuit. There are used as filters and reflector antenna as well as deep-space exploration for multi-frequencies operations. A simple FSS structure is studied in the first stage to validate our approach. In the second stage two different complex structures are studied. The good agreement between simulated and published data justifies the design procedure.
Image-guided needles are currently used for drug delivery in bodies, but the additional time associated with aligning and maintaining the needle’s position results in increased patient discomfort or risk of invasion of the human body. In this paper, a needle guidance system using piezoelectric materials is designed and analyzed for precise drug delivery without damaging parts of the body and improving processing time. A piezoelectric generates an ultrasound wave that can propagate through different mediums, and a second piezoelectric crystal can receive that energy and convert it into voltage. A 1D real-time image represents the changes of the voltage induced in the double piezoelectric crystal. Extensive data analysis and visualization are done using different obstacles and location of the needle verified for other mediums. The presence of obstacles in between those crystals can be identified in the real-time grayscale image. The needle can reach its destination using this image information as directional guidance. This guided drug delivery improves patient recovery time and eliminates extra injuries that can be caused due to wrong needle injections, such as lumbar puncture-related nerve damage.
This paper presents a floating resistor employing CIDITA (current inverting differential input transconductance amplifier). The proposed floating resistor is based on CMOS technology of 0.18 μm. For the realization of this floating inductor, two CIDITA have been cascaded together, no other passive elements are used, giving advantage of reduced chip area and hence reduced losses. The given circuit topology has an advantage of realizing both positive and negative resistors. This paper presents a simple circuitry of floating resistor in which the value of resistance can be tuned by adjusting the gate voltage of MOSFET. The PSpice simulation result shows constant resistance of 1.6 KΩ for frequency bandwidth of 1 Hz to 1 MHz, with supply voltage of ±1.25 volts.
