Reduced Hardware Requirements Research Articles

Hierarchical voltage balancing method for MMC based on DCSM

This paper presents a hierarchical voltage balance control method for a hybrid modular multi-level converter based on half-bridge submodule and dual-capacitor submodule. This voltage balancing method reduces the control complexity of the existing voltage balancing method of the central controller but does not significantly increase the control complexity of the submodule controller. In dual-capacitor submodule, only some logic operations are added. Furthermore, the proposed method reduces the hardware requirements and communication data between the submodule and central controllers. The reduced hardware requirements refer to the hardware circuits used to implement communication functions. The proposed method is also applicable to multi-level converter, which only includes half-bridge submodules, but requires two adjacent half-bridge submodules to use the same submodule controller. Simulation and experimental results validate the feasibility and effectiveness of the proposed hierarchical voltage balance control.

Design of a Grating Lobes-Free Architecture for Distributed Sensor System with Arbitrary Element Spacing

Two main difficulties for the accurate direction of arrival (DOA) estimation in a distributed sensor system are grating lobes and system synchronization. Different from the traditional phased array system based on single carrier frequency, this paper designs a novel architecture for distributed sensor system using dual carrier frequency measurements. Both two carrier frequencies are combined and transmitted simultaneously in the proposed architecture. Instead of single carrier frequency f1 in the traditional method, the frequency separation f2−f1 is used in the proposed algorithm to determine a maximum unambiguous DOA estimate. Since f2−f1 is much less than f1 and the choice of f2−f1 is more flexible, the proposed method can provide an unambiguous DOA estimate in the whole field of view (FOV) for arbitrary element spacing and a looser requirement on system synchronization than the traditional method based on single carrier frequency. For a case with f1=3 Ghz, f2−f1=150 Mhz and 10 times element spacing, there is no grating lobe for the proposed method in the whole FOV [−π/2,π/2], whereas the traditional method has many grating lobes and the FOV of the traditional method without grating lobes is only 5.73∘. To obtain the same combining efficiency in this case, the requirement on the positioning error of the proposed method is 0.4 m and the location error of the traditional method must be smaller than 0.02 m. Hence, the proposed method can greatly reduce hardware requirements. The performances of the proposed architecture for the cases with perfect and imperfect system synchronizations are evaluated in terms of the average beampattern and combining efficiency, respectively. Some characteristics of the derived beampattern and combining efficiency are also presented in the paper.

Fibular Strut Autograft as an Augmented Biological Plate: A New Modified Technique for Tibiocalcaneal Arthrodesis With Intramedullary Nail

Fibular Strut Autograft as an Augmented Biological Plate: A New Modified Technique for Tibiocalcaneal Arthrodesis With Intramedullary Nail

М. О. Любимов, Н. С. Педченко, О. В. Артюх-Пасюта, А. І. Мілька, Н. В. Прохар РОЗВИТОК ОРГАНІЗАЦІЇ БУХГАЛТЕРСЬКОГО ОБЛІКУ В УКРАЇНІ В СУЧАСНИХ УМОВАХ

The purpose of the article is to substantiate the directions of development of the organization of accounting in Ukraine in modern conditions. Methodology of research. Achievement of the goal set in the article is carried out with the help of the following research methods: logical generalization and scientific abstraction, structural analysis, and analytical method. Results. According to the results of the study, the modern features of the environment in which Ukrainian enterprises operate are characterized: by the unpredictable economic and political situation in Ukraine; constant changes in the regulatory framework for accounting and taxation; widespread use of cloud and network technologies and calculations, which allows accountants to significantly reduce hardware requirements and use computers and smartphones of the budget segment when working with accounting software. At the same time, the widespread use of cloud and network technologies provides more opportunities for regulatory authorities. Considering that the components of the organization of accounting at the enterprise are organizational, technical, and methodological, it is determined that the methodological component, that is, the accounting method, will be least affected under the new conditions. At the same time, the new business conditions significantly impact the organization of the work of accounting employees and the technique of keeping records. The main questions regarding the organization of accounting at the enterprise are formulated, which need to be solved and reconsidered in the context of modern economic and labor conditions. The study showed the lack of comprehensive research on the organization of accounting in the context of digitalization and the use of remote technologies. It is determined that the fragmentation of these studies is natural and logical since they cover issues of psychology, staff development, and issues of regulatory regulation of labor relations, and a very wide range of specific technical issues. It has been determined that the further development of the organization of accounting shortly will affect its organizational and technical components through the implementation of modern technological solutions and the development of the practice of remote work. The practical significance of the research results. The use of the proposed ideas allows for determining the optimal directions for improving the organization of accounting at a particular enterprise.

Emerging Technologies for Quantum Computing

Despite promising proof of concept demonstrations, currently available quantum hardware suffers from fundamental scalability limitations. The field is relatively new and it is imperative to consider emerging technologies in the space and evaluate their unique tradeoff spaces to determine how to best close the gap between current devices and target applications. Here, we explore three recent developments on this front. First, we consider extensions to currently available hardware, which allow the use of higher level states, beyond the usual binary, which when used temporarily can confer circuit-level advantage. Second, we consider the use of superconducting resonant cavities to reduce hardware requirements to implement quantum error correction protocols. Finally, we consider the use of neutral atoms, which offer unique strengths and weaknesses. It is valuable to evaluate new technology early and often to determine the best path toward scalability.

Measuring Key Quality Indicators in Cloud Gaming: Framework and Assessment Over Wireless Networks.

Cloud Gaming is a cutting-edge paradigm in the video game provision where the graphics rendering and logic are computed in the cloud. This allows a user’s thin client systems with much more limited capabilities to offer a comparable experience with traditional local and online gaming but using reduced hardware requirements. In contrast, this approach stresses the communication networks between the client and the cloud. In this context, it is necessary to know how to configure the network in order to provide service with the best quality. To that end, the present work defines a novel framework for Cloud Gaming performance evaluation. This system is implemented in a real testbed and evaluates the Cloud Gaming approach for different transport networks (Ethernet, WiFi, and LTE (Long Term Evolution)) and scenarios, automating the acquisition of the gaming metrics. From this, the impact on the overall gaming experience is analyzed identifying the main parameters involved in its performance. Hence, the future lines for Cloud Gaming QoE-based (Quality of Experience) optimization are established, this way being of configuration, a trendy paradigm in the new-generation networks, such as 4G and 5G (Fourth and Fifth Generation of Mobile Networks).

Active Realization of Fractional-Order Integrators and Their Application in Multiscroll Chaotic Systems

This paper presents the design, simulation, and experimental verification of the fractional-order multiscroll Lü chaotic system. We base them on op-amp-based approximations of fractional-order integrators and saturated series of nonlinear functions. The integrators are first-order active realizations tuned to reduce the inaccuracy of the frequency response. By an exponential curve fitting, we got a convenient design equation for realizing fractional-order integrators of orders from 0.1 to 0.95. The results include simulations in SPICE of the mathematical description and the electronic implementation and experimental measurements that confirm them. Monte Carlo and sensitivity tests revealed a robust realization. Contrary to its passive counterparts, the suggested realizations significantly reduce design and implementation efforts by favoring resistors and capacitors with commercial values and reducing hardware requirements.

Three‐phase two‐leg buck‐boost DC‐AC inverter with differential power processor unit

SummaryRenewable energy sources (RESs) need power‐electronics‐based converters to deliver the acquired power to the grid. Those converters should provide voltage‐bucking/boosting capabilities to accommodate various grid modes specially for three‐phase distorted commonly unbalanced distribution utility networks. Several power electronic‐based converters have been elaborated to fulfill this high‐demand market. Single‐stage converters are the most dominant in the market where the current source inverters (CSIs), impedance source inverters (ZSIs), and boost inverters are the high‐end candidates. The aspects of cost, footprint, and minimal numbers of active switches, in addition to simplified controllability, build the main challenges that face the evolution of robust renewable energy‐associated grid‐tied converters. This paper presents a novel three‐phase differential‐mode buck‐boost inverter based on two bidirectional buck‐boost DC/DC converters and one differential power processor (DPP) unit. The proposed topology is a single‐stage DC/AC converter offering bucking/boosting capability, with reduced hardware requirements. The proposed topology features a simplified control methodology in addition to reduced size and cost of the hardware setup which makes it more suitable for grid‐tied renewable energy applications. The operation principles, small‐signal model, and control strategy of the proposed topology are also illustrated. Simulation and experimental results are presented in details to verify the topology‐enhanced performance under various operating conditions. The deducted results elucidate the viability of the proposed configuration alongside with the claimed merits.

On the Suitability of Compressive Sampling for LoRa Signals Classification

Sensor networks require even more reliable and power saving communication systems, especially as regards to Internet of Things paradigm. In this scenario, LoRa technology, based on an efficient Chirp Spread Spectrum modulation, is well tailored, granting both long range distance and low energy consumption in the communication link. Even though it is a recent solution, several instrumentation manufacturers are providing test facilities and setups to carry out reliable measurements on LoRa signals in both laboratory experiments and on-field applications. Unfortunately, these solutions are usually given as upgrade of expensive instruments operating in time and/or frequency domain. To overcome this drawback, the authors propose hereinafter an innovative approach based on compressive sampling to suitably reduce hardware requirements and dependably reconstruct the signal of interest from a reduced number of samples acquired in time domain. To assess its reliability and the potential attractiveness, the proposed methodology has been exploited to extract characteristic parameters from actual LoRa signals by mean of an experimental set-up, which takes care of their generation and acquisition. The obtained results highlight the promising performance of the proposed approach.

MPC-Based Fast Frequency Control of Voltage Source Converters in Low-Inertia Power Systems

A rapid deployment of renewable generation has led to significant reduction in the rotational system inertia and damping, thus making frequency control in power systems more challenging. This paper proposes a novel control scheme based on Model Predictive Control (MPC) for converter-interfaced generators operating in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">grid-forming</i> mode, with the goal of exploiting their fast response capabilities to provide fast frequency control service to the system. The controller manipulates converter power injections to limit the frequency nadir and rate-of-change-of-frequency after a disturbance. Both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">centralized</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">decentralized</i> MPC approaches are considered and compared in terms of performance and practical implementation. Special attention is given to the decentralized controller by generating an explicit MPC solution to enhance computational efficiency and reduce hardware requirements. Simulation results obtained from a detailed dynamic model of the IEEE 39-bus system demonstrate the effectiveness of the proposed control schemes.

Simple quantum key distribution with qubit-based synchronization and a self-compensating polarization encoder

Quantum key distribution (QKD) relies on quantum communication to allow distant parties to share a secure cryptographic key. Widespread adoption of QKD in current telecommunication networks will require the development of simple, low-cost, and stable systems. However, current QKD implementations usually include additional hardware that perform auxiliary tasks such as temporal synchronization and polarization basis tracking. Here we present a polarization-based QKD system operating at 1550 nm that performs synchronization and polarization compensation by exploiting only the hardware already needed for the quantum communication task. Polarization encoding is performed by a self-compensating Sagnac loop modulator that exhibits high temporal stability and the lowest intrinsic quantum bit error rate reported so far. The QKD system was tested over a fiber-optic link, demonstrating tolerance up to about 40 dB of channel losses. Due to its reduced hardware requirements and the quality of the source, this work represents an important step towards technologically mature QKD systems.

Key Technology Research of Electric Cars Smart Dynamic Interactive Terminal Charging Path Planning

In the future a large-scale of electric vehicles will have mutual interact and influence with cities’ intelligent transportation network and intelligent grid network. In recent years, with the popularity of the third-generation mobile communication technology, the use of the Internet for dynamic traffic information and navigation is competent for the traffic information transmission requirements, which can effectively reduce hardware requirements, expand the popularity of dynamic vehicle navigation technology. In this context, this paper proposes a “center” type of electric car charging dynamic route planning service system architecture, and the architecture of the server-side data management technology and services were studied, through GIS technology, the optimal allocation of each electric vehicle charging stations ultimately comes true, which ensures the coordination and harmonization of electric vehicles, charging stations and users, saves the time for travel and charging, and improves operating efficiency.

Integrated UAV-Based Real-Time Mapping for Security Applications

Security applications such as management of natural disasters and man-made incidents crucially depend on the rapid availability of a situation picture of the affected area. UAV-based remote sensing systems may constitute an essential tool for capturing aerial imagery in such scenarios. While several commercial UAV solutions already provide acquisition of high quality photos or real-time video transmission via radio link, generating instant high-resolution aerial maps is still an open challenge. For this purpose, the article presents a real-time processing tool chain, enabling generation of interactive aerial maps during flight. Key element of this tool chain is the combination of the Terrain Aware Image Clipping (TAC) algorithm and 12-bit JPEG compression. As a result, the data size of a common scenery can be reduced to approximately 0.4% of the original size, while preserving full geometric and radiometric resolution. Particular attention was paid to minimize computational costs to reduce hardware requirements. The full workflow was demonstrated using the DLR Modular Airborne Camera System (MACS) operated on a conventional aircraft. In combination with a commercial radio link, the latency between image acquisition and visualization in the ground station was about 2 s. In addition, the integration of a miniaturized version of the camera system into a small fixed-wing UAV is presented. It is shown that the described workflow is efficient enough to instantly generate image maps even on small UAV hardware. Using a radio link, these maps can be broadcasted to on-site operation centers and are immediately available to the end-users.

A new method for designing multiplierless two-channel filterbank using shifted-Chebyshev polynomials

ABSTRACTThis paper presents an efficient design method for a digital multiplierless two-channel filterbank using the shifted-Chebyshev polynomials and common sub-expression elimination (CSE) algorithm for reducing hardware requirements such as adders and multipliers. For designing a two-channel filterbank, the design problem is constructed as minimization of integral mean square error between the desired and designed response of a prototype filter in the passband and stopband. For controlling the performance in passband and stopband, two parameters (KP, and KS) are used, whose optimum values are determined by swam optimization techniques such as differential evolution algorithm, artificial bee colony optimization, particle swarm optimizations, cuckoo search algorithm and hybrid method using a fitness function, constructed by perfect reconstruction condition of a filterbank. The number of polynomials used for approximation depends upon the order of a prototype filter. A new hybrid CSE is proposed for further reduction of hardware requirement. A comparative study of various CSE techniques such as horizontal, vertical and proposed hybrid CSE is also made. Numerical examples illustrate the effectiveness of the proposed algorithm in the reduction of adders with comparisons accomplished using existing methods. It has been found that almost 43% adder gain can be achieved when a filter is designed with N = 32 and wordlength (WL) as 12 using proposed methodology.

Power Harvesting in Wireless Sensor Networks and Its Adaptation With Maximum Power Point Tracking: Current Technology and Future Directions

Wireless sensor networks (WSNs) is one of the most effective tools in collecting data autonomously going as recently as 5–10 years ago. A low deployment and maintenance cost WSN is highly recognized as one of the more advanced Internet of Things networks that can be deployed for a series of purposes namely environmental and industrial monitoring due to the majority of such systems run on expendable power source that offers WSN with a limited service lifetime. The aim of this paper is to review existing renewable energy and prospective approaches in energy harvesting strategy as a means of having a sustainable and low maintenance operation of WSN. Additionally, recent maximum power point tracking (MPPT) of solar energy harvesting is thoroughly discussed in a new perspective of the WSN framework. Semi-pilot cell fractional open-circuit voltage (SPC-FOCV) MPPT is a fairly new concept in WSN application that features less complicated configuration with reduced hardware requirements and lower cost. Recent research findings are evaluated throughout this paper leading to the SPC-FOCV MPPT materialization. A holistic discussion is made encompassing the advantages and disadvantages of the concept, its performance compared to conventional MPPT approaches and the future insight of the technology in WSN.

A Modified Hybrid RF Predistorter Linearizer for Ultra Wideband 5G Systems

The wide-bandwidth signal transmission is one of the requirements in upcoming 5G communication systems in its quest for high data rates. In this paper, a wideband hybrid RF/digital predistortion (HRF-DPD) linearization technique is reported to compensate for the nonlinearity of ultra-wideband power amplifier (PA) for 5G systems driven by carrier aggregated and wideband modulated signals. The proposed methodology is suitable for 5G PA design, since its power overhead and system bandwidth does not increase with an increase in signal bandwidth. Taking advantage of recent available digital signal processing solutions, the proposed method reduces hardware requirements of the conventional analog predistorter by alleviating the need of vector multiplier, branch line coupler, and delay lines. Such linear operations are controlled digitally, which provides flexibility in terms of digitally compensation of delay, gain and phase control of the signal. For establishing a proof of concept, HRF-DPD is implemented with ZX60V-82+ class AB PA and tested using a 100- and 50-MHz long term evolution-carrier aggregated (LTE-CA) signal at 2 GHz. Experimental results show that the wideband PA along with the proposed predistorter delivers an adjacent channel leakage ratio (ACLR) of −54 dBc with a cancellation of 30.6 dB for 100-MHz LTE-CA signal. With the proposed method PA, nonlinear distortion outside the 100-MHz band can be linearized leading to filter less architecture which provides 45-dBc ACLR performance.

Experimental Validation of On-Site Coding Digital Beamformer With Ultra-Wideband Antenna Arrays

Digital beamformers combined with ultra-wideband (UWB) antennas are essential for realizing cognitive and software defined radios. Concurrently, advances in digital technology and signal processing have drastically reduced digital beamforming complexity. Recently, a novel on-site coding receiver (OSCR) architecture was proposed to significantly reduce hardware requirement for digital beamforming. Using OSCR, the signal from each antenna element is encoded, then several of these signals are grouped and digitized using a single analog-to-digital converter. Doing so, hardware requirements are drastically reduced. At the digital back-end, field programmable gate arrays are used to decorrelate and recover the signals associated with each array element for beamforming. In this paper, we demonstrate the effectiveness of the OSCR concept by building and testing a multichannel receiver using commercial-off-the-shelf components. Various test bench measurements are performed in an anechoic chamber using an UWB antenna array operating from 200 MHz–2.5 GHz, and data were collected at multiple frequencies. Results show an accurate estimate of the angle of arrival for incidence angles of $\theta _{s} = 0^{\circ }$ , 15°, 30°, and 45° away from broadside. It is verified that on-site coding has minimal or no degradation in signal-to-noise ratio.

Multiband and Multibeam Direction of Arrival Estimation Using On-Site Coding Digital Beamformer

Ultrawideband system with digital beamforming allows for spatial filtering and multiuser detection without degradation of the signal-to-noise ratio (SNR). Along these lines, we propose a novel on-site coding receiver (OSCR) architecture for digital beamforming that has already been verified to significantly reduce hardware requirement at the analog back end. Using OSCR, the signal from each antenna element is encoded, then several antenna signals are grouped and digitized using a single analog-todigital converter (ADC). At the digital back end, single field programmable gate arrays (FPGAs) are used for beamforming. In this letter, an 8-channel OSCR is tested for spatial filtering and spectral diversity using a tightly coupled dipole array operating from 290 to 3900 MHz. Measurements were performed in an anechoic chamber using two transmit signals, modulated simultaneously at 1350 and 1800 MHz and arriving from various angles across 0° to ±50°. Results show that an accurate estimate of the angle of arrival is achieved with error <;1.8°. Also, we show that on-site coding has minimal degradation to SNR in a multibeam and multiband environment. Therefore, the proposed architecture is highly suitable for multiple-input-multiple-output (MIMO) applications.

High-Density Liquid-State Machine Circuitry for Time-Series Forecasting.

Spiking neural networks (SNN) are the last neural network generation that try to mimic the real behavior of biological neurons. Although most research in this area is done through software applications, it is in hardware implementations in which the intrinsic parallelism of these computing systems are more efficiently exploited. Liquid state machines (LSM) have arisen as a strategic technique to implement recurrent designs of SNN with a simple learning methodology. In this work, we show a new low-cost methodology to implement high-density LSM by using Boolean gates. The proposed method is based on the use of probabilistic computing concepts to reduce hardware requirements, thus considerably increasing the neuron count per chip. The result is a highly functional system that is applied to high-speed time series forecasting.

A Survey on Smartphone-Based Crowdsensing Solutions

In recent years, the widespread adoption of mobile phones, combined with the ever-increasing number of sensors that smartphones are equipped with, greatly simplified the generalized adoption of crowdsensing solutions by reducing hardware requirements and costs to a minimum. These factors have led to an outstanding growth of crowdsensing proposals from both academia and industry. In this paper, we provide a survey of smartphone-based crowdsensing solutions that have emerged in the past few years, focusing on 64 works published in top-ranked journals and conferences. To properly analyze these previous works, we first define a reference framework based on how we classify the different proposals under study. The results of our survey evidence that there is still much heterogeneity in terms of technologies adopted and deployment approaches, although modular designs at both client and server elements seem to be dominant. Also, the preferred client platform is Android, while server platforms are typically web-based, and client-server communications mostly rely on XML or JSON over HTTP. The main detected pitfall concerns the performance evaluation of the different proposals, which typically fail to make a scalability analysis despite being critical issue when targeting very large communities of users.