scholarly journals Energy Minimization Algorithm for Estimation of Clock Skew and Reception Window Selection in Wireless Networks

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1768
Author(s):  
Michał Gorawski ◽  
Krzysztof Grochla ◽  
Rafał Marjasz ◽  
Artur Frankiewicz
Keyword(s):  
Wireless Networks ◽  
Time Window ◽  
Clock Synchronization ◽  
Window Size ◽  
Packet Transmission ◽  
Energy Utilization ◽  
Clock Skew ◽  
Window Selection ◽  
Reception Window ◽  
Selection Of

The synchronization of time between devices is one of the more important and challenging problems in wireless networks. We discuss the problem of maximization of the probability of receiving a message from a device using a limited listening time window to minimize energy utilization. We propose a solution to two important problems in wireless networks of battery-powered devices: a method of establishing a connection with a device that has been disconnected from the system for a long time and developed unknown skew and also two approaches to follow-up clock synchronization using the confidence interval method. We start with the analysis of measurements of clock skew. The algorithms are evaluated using extensive simulations and we discuss the selection of parameters balancing between minimizing the energy utilization and maximizing the probability of reception of the message. We show that the selection of a time window of growing size requires less energy to receive a packet than using the same size of time window repeated multiple times. The shifting of reception windows can further decrease the energy cost if lower packet reception probability is acceptable. We also propose and evaluate an algorithm scaling the reception window size to the interval between the packet transmission.

Selection of Suitable Window Size for Speckle Reduction and Deblurring using SOFM in Polarimetric SAR Images

2015 ◽  
Vol 43 (4) ◽  
pp. 739-750 ◽  
Author(s):  
Sanjay Shitole ◽  
Shaunak De ◽  
Y. S. Rao ◽  
B. Krishna Mohan ◽  
Anup Das
Keyword(s):  
Window Size ◽  
Speckle Reduction ◽  
Polarimetric Sar ◽  
Sar Images ◽  
Selection Of

scholarly journals Design of Shrewd Underwater Routing Synergy using Porous Energy Shells

2020 ◽  
Author(s):  
Shahzad Ashraf ◽  
Tauqeer Ahmed ◽  
Asif Raza ◽  
Hamad Naeem
Keyword(s):  
Cost Effective ◽  
Research Direction ◽  
Residual Energy ◽  
Data Packet ◽  
Energy Utilization ◽  
Quality Inspection ◽  
Energy Status ◽  
Active Devices ◽  
Packet Delivery ◽  
Selection Of

Abstract Underwater sensors link establishment and quality inspection challenges are blurt out during ubiquitous data monitoring. The energy utilization has a direct impact because all active devices are battery dependents and no charging or replacement actions could be made when cost- effective data packet delivery has been set as a benchmark. The hop link inspection and the selection of a Shrewd link through resurrecting link factor was a nothing short of bleak challenge which could only be made possible after going through meticulous research by developing a shrewd underwater routing synergy using extra porous energy shells (SURS-PES) which might never have conducted of before. After broadcasting packets the sensor node conducts a link inspection phase thereby, if any link is found to be less than or equal to 50% shaky; the destination receiving node puts in own residual energy status and return back to the source node which in result adds some unusable energy porous shell to strengthen the link from 50 to 90% at most and send it only to the targeted node and an unaltered data packet delivery is anticipated. Performance evaluation has been carried out using NS2 simulator and obtained results have been compared with DBR and EEDBR to observe the distinguish outcomes thereon results in vouches for the statement that has been made earlier for this research direction.

MULTI-PHASE ROTARY CLOCK SYNCHRONIZATION OF LEVEL-SENSITIVE CIRCUITS

2009 ◽  
Vol 18 (05) ◽  
pp. 899-908 ◽  
Author(s):  
BARIS TASKIN ◽  
IVAN KOURTEV
Keyword(s):  
Phase Synchronization ◽  
Clock Synchronization ◽  
Clock Skew ◽  
Clock Period ◽  
Flip Flop ◽  
Clock Networks ◽  
Significant Performance ◽  
Clock Skew Scheduling ◽  
Time Borrowing ◽  
Multi Phase

Resonant clocking technologies provide clock networks with improved frequency, jitter and power dissipation characteristics, however, often require novel automation routines. Resonant rotary clocking technology, for instance, entails multi-phase and nonzero clock skew operation and supports latch-based design. This paper studies the effects of multi-phase synchronization schemes on the minimum clock period for rotary-clock-synchronized circuits, which necessitate the application of clock skew scheduling and employ level-sensitive registers. In experimentation, single, dual, three- and four-phase clocking schemes generated by rotary clock synchronization are applied to a suite of level-sensitive-transformed ISCAS'89 benchmarks. Average clock period improvements of 30.3%, 24.8%, 17.7% and 12.0%, respectively, are observed on average compared to the flip-flop based, zero clock skew circuits. As the number of clock phases increases, smaller improvements are observed due to lesser overall effectiveness of the complementary effects of clock skew scheduling and time borrowing. It is shown, however, that for some circuits (23% of the benchmarks), multi-phase synchronization leads to significant performance benefits in operating frequency.

Cross-borehole tomography with correlation delay times

Geophysics ◽  
2014 ◽  
Vol 79 (1) ◽  
pp. R1-R12 ◽  
Author(s):  
E. Diego Mercerat ◽  
Guust Nolet ◽  
Christophe Zaroli
Keyword(s):  
Time Window ◽  
Body Wave ◽  
Wave Dispersion ◽  
Spectral Element ◽  
Frequency Theory ◽  
P Wave ◽  
Checkerboard Pattern ◽  
Finite Frequency ◽  
Delay Times ◽  
Window Selection

We evaluated a comprehensive numerical experiment of finite-frequency tomography with ray-based (“banana-doughnut”) kernels that tested all aspects of this method, starting from the generation of seismograms in a 3D model, the window selection, and the crosscorrelation with seismograms predicted for a background model, to the final regularized inversion. In particular, we tested if the quasilinearity of crosscorrelation delays allowed us to forego multiple (linearized) iterations in the case of strong reverberations characterizing multiple scattering and the gain in resolution that can be obtained by observing body-wave dispersion. Contrary to onset times, traveltimes observed by crosscorrelation allowed us to exploit energy arriving later in the time window centered in the P-wave or any other indentifiable ray arrival, either scattered from, or diffracted around, lateral heterogeneities. We tested using seismograms calculated by the spectral element method in a cross-borehole experiment conducted in a 3D checkerboard cube. The use of multiple frequency bands allowed us to estimate body-wave dispersion caused by diffraction effects. The large velocity contrast (10%) and the regularity of the checkerboard pattern caused severe reverberations that arrived late in the crosscorrelation windows. Nevertheless, the model resulting from the inversion with a data fit with reduced [Formula: see text] resulted in an excellent correspondence with the input model and allowed for a complete validation of the linearizations that lay at the basis of the theory. The use of multiple frequencies led to a significant increase in resolution. Moreover, we evaluated a case in which the sign of the anomalies in the checkerboard was systematically reversed in the ray-theoretical solution, a clear demonstration of the reality of the “doughnut-hole” effect. The experiment validated finite-frequency theory and disqualified ray-theoretical inversions of crosscorrelation delay times.

Reliability of Congestion Control Based on Packet Transmission Interval with Hybrid ARQ

2021 ◽  
pp. 2140004
Author(s):  
Mitsutaka Kimura ◽  
Mitsuhiro Imaizumi ◽  
Takahito Araki
Keyword(s):  
Congestion Control ◽  
Error Correction ◽  
High Performance ◽  
Data Communication ◽  
Window Size ◽  
Correction Method ◽  
Packet Transmission ◽  
Hybrid Arq ◽  
Packet Losses ◽  
Data Packets

Code error correction methods have been important techniques at a radio environment and video stream transmission. In general, when a server transmits some data packets to a client, the server resends the only loss packets. But in this method, a delay occurs in a transmission. In order to prevent the transmission delay, the loss packets are restored by the error correction packet on a client side. The code error correction method is called Hybrid Automatic Repeat reQuest (ARQ) and has been researched. On the other hand, congestion control schemes have been important techniques at a data communication. Some packet losses are generated by network congestion. In order to prevent some packet losses, the congestion control performs by prolonging packet transmission intervals, which is called High-performance and Flexible Protocol (HpFP). In this paper, we present a stochastic model of congestion control based on packet transmission interval with Hybrid ARQ for data transmission. That is, if the packet loss occurs, the data packet received in error is restored by the error correction packet. Moreover, if errors occur in data packets, the congestion control performs by prolonging packet transmission intervals. The mean time until packet transmissions succeed is derived analytically, and a window size which maximizes the quantity of packets per unit of time until the transmission succeeds is discussed.

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