scholarly journals Wlan Performance Improvement by Header Compression and Packet Overhearing Reduction

2014 ◽  
Vol 65 (4) ◽  
pp. 203-212
Author(s):  
David Levy ◽  
Ivan Kotuliak ◽  
Peter Trúchly

Abstract For wireless systems, it is of vital importance to use the scarce radio resources in an efficient way. The main targets are to reduce the power consumption and increase the throughput of wireless devices. Using header compression both throughput can be increased and power can be saved. Using packet overhearing reduction power can be saved. This paper presents the achieved performance improvements when using these two methods. The simulation results are confirmed by analytical calculations. We show that we can achieve up to 35% power save when combining both methods and close to 0.1 additional normalized throughput.

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1639
Author(s):  
Seungmin Jung ◽  
Jihoon Moon ◽  
Sungwoo Park ◽  
Eenjun Hwang

Recently, multistep-ahead prediction has attracted much attention in electric load forecasting because it can deal with sudden changes in power consumption caused by various events such as fire and heat wave for a day from the present time. On the other hand, recurrent neural networks (RNNs), including long short-term memory and gated recurrent unit (GRU) networks, can reflect the previous point well to predict the current point. Due to this property, they have been widely used for multistep-ahead prediction. The GRU model is simple and easy to implement; however, its prediction performance is limited because it considers all input variables equally. In this paper, we propose a short-term load forecasting model using an attention based GRU to focus more on the crucial variables and demonstrate that this can achieve significant performance improvements, especially when the input sequence of RNN is long. Through extensive experiments, we show that the proposed model outperforms other recent multistep-ahead prediction models in the building-level power consumption forecasting.


2020 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Po-Yu Kuo ◽  
Ming-Hwa Sheu ◽  
Chang-Ming Tsai ◽  
Ming-Yan Tsai ◽  
Jin-Fa Lin

The conventional shift register consists of master and slave (MS) latches with each latch receiving the data from the previous stage. Therefore, the same data are stored in two latches separately. It leads to consuming more electrical power and occupying more layout area, which is not satisfactory to most circuit designers. To solve this issue, a novel cross-latch shift register (CLSR) scheme is proposed. It significantly reduced the number of transistors needed for a 256-bit shifter register by 48.33% as compared with the conventional MS latch design. To further verify its functions, this CLSR was implemented by using TSMC 40 nm CMOS process standard technology. The simulation results reveal that the proposed CLSR reduced the average power consumption by 36%, cut the leakage power by 60.53%, and eliminated layout area by 34.76% at a supply voltage of 0.9 V with an operating frequency of 250 MHz, as compared with the MS latch.


Author(s):  
F. W. Huber ◽  
P. D. Johnson ◽  
O. P. Sharma ◽  
J. B. Staubach ◽  
S. W. Gaddis

This paper describes the results of a study to determine the performance improvements achievable by circumferentially indexing successive rows of turbine stator airfoils. An experimental / analytical investigation has been completed which indicates significant stage efficiency increases can be attained through application of this airfoil clocking concept. A series of tests was conducted at the National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) to experimentally investigate stator wake clocking effects on the performance of the Space Shuttle Main Engine Alternate Fuel Turbopump Turbine Test Article. Extensive time-accurate Computational Fluid Dynamics (CFD) simulations have been completed for the test configurations. The CFD results provide insight into the performance improvement mechanism. Part one of this paper describes details of the test facility, rig geometry, instrumentation, and aerodynamic operating parameters. Results of turbine testing at the aerodynamic design point are presented for six circumferential positions of the first stage stator, along with a description of the initial CFD analyses performed for the test article. It should be noted that first vane positions 1 and 6 produced identical first to second vane indexing. Results obtained from off-design testing of the “best” and “worst” stator clocking positions, and testing over a range of Reynolds numbers are also presented. Part two of this paper describes the numerical simulations performed in support of the experimental test program described in part one. Time-accurate Navier-Stokes flow analyses have been completed for the five different turbine stator positions tested. Details of the computational procedure and results are presented. Analysis results include predictions of instantaneous and time-average mid-span airfoil and turbine performance, as well as gas conditions throughout the flow field. An initial understanding of the turbine performance improvement mechanism is described.


2002 ◽  
Vol 11 (01) ◽  
pp. 51-55
Author(s):  
ROBERT C. CHANG ◽  
L.-C. HSU ◽  
M.-C. SUN

A novel low-power and high-speed D flip-flop is presented in this letter. The flip-flop consists of a single low-power latch, which is controlled by a positive narrow pulse. Hence, fewer transistors are used and lower power consumption is achieved. HSPICE simulation results show that power dissipation of the proposed D flip-flop has been reduced up to 76%. The operating frequency of the flip-flop is also greatly increased.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vieri Maestrini ◽  
Andrea Stefano Patrucco ◽  
Davide Luzzini ◽  
Federico Caniato ◽  
Paolo Maccarrone

PurposeGrounding on resource orchestration theory, this paper aims to study the relationship between the way buying companies use their supplier performance measurement systems and the performance improvements obtained from suppliers, with relationship trust identified as a mediator in the previous link.Design/methodology/approachThe authors design a conceptual model and test it through structural equation modelling on a final sample of 147 buyer-supplier responses, collected by means of a dyadic survey.FindingsResults suggest that the buyer company may achieve the most by balancing a diagnostic and interactive use of the measurement system, as they are both positively related to supplier performance improvement. Furthermore, relationship trust acts as a mediator in case of the interactive use, but not for the diagnostic. This type of use negatively affects relationship trust, due to its mechanistic use in the buyer-supplier relationship.Originality/valueThe authors’ results contribute to the current academic debate about supplier performance measurement system design and use by analyzing the impact of different supplier performance measurement system uses, and highlighting their relative impact on relationship trust and supplier performance improvement. From a methodological perspective, adopting a dyadic data collection process increases the robustness of the findings.


This paper deals with sensorless vector controlled induction motor in which torque pulsations are reduced with improved input of induction motor. In proposed technique two multi winding transformers are used for generation of 18 sinusoidal signals given to rectifier unit and the rectifier output given as input to 9 level multi level inverter. In this proposed technique gating signals to the inverter switches will be provided through space vector pulse width modulation which considers speed as reference. This configuration was simulated in MATLAB/Simulink.and the simulation results are presented here with improvement in reduction of THD.


2019 ◽  
Vol 8 (2) ◽  
pp. 6527-6534

Massive Multi-Input and Multi-Output (MIMO) antenna system potentially provides a promising solution to improve energy efficiency (EE) for 5G wireless systems. The aim of this paper is to enhance EE and its limiting factors are explored. The maximum EE of 48 Mbit/Joule was achieved with 15 user terminal (UT)s. This problem is related to the uplink spectral efficiency with upper bound for future wireless networks. The maximal EE is obtained by optimizing a number of base station (BS) antennas, pilot reuse factor, and BSs density. We presented a power consumption model by deriving Shannon capacity calculations with closed-form expressions. The simulation result highlights the EE maximization with optimizing variables of circuit power consumption, hardware impairments, and path-loss exponent. Small cells achieve high EE and saturate to a constant value with BSs density. The MRC scheme achieves maximum EE of 36 Mbit/Joule with 12 UTs. The simulation results show that peak EE is obtained by deploying massive BS antennas, where the interference and pilot contamination are mitigated by coherent processing. The simulation results were implemented by using MATLAB 2018b.


2019 ◽  
Vol 30 ◽  
pp. 01006
Author(s):  
Alexander Kozhemyakin ◽  
Ivan Kravchenko

The paper presents design flow and simulation results of the W-band fundamental voltage-controlled oscillator in 0.13 μm SiGe BiCMOS technology for an automotive radar application. Oscillator provides fundamental oscillation range of 76.8 GHz to 81.2 GHz. According to simulation results phase noise is –89.3 dBc/Hz at 1 MHz offset, output power is –5.6 dBm and power consumption is 39 mW from 3.3 V source.


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