scholarly journals Comparison and an Improved Validation Optimistic Approach for Concurrency Control

2019 ◽  
pp. 16-21
Author(s):  
Monika Patel ◽  
Dhiren B. Patel
Keyword(s):  
Concurrency Control ◽  
Analytical Modeling ◽  
Distributed Database ◽  
Database System ◽  
New Technique ◽  
Control Technique ◽  
Validation Method ◽  
Control Techniques ◽  
Timestamp Ordering ◽  
A New Technique

Concurrency Control entails the synchronization of accesses to the distributed database, such that the integrity of the database is maintained. Devising an efficient concurrency control technique is challenging. There is a need for improvised concurrency control technique to coordinate the simultaneous execution of transactions in a multi-processing database system. Traditionally, concurrency control techniques are locking, timestamp ordering and optimistic. These techniques have been evaluated by analytical modeling. In this undertaken work, the analytical modeling has been investigated and evaluated. The concurrency control in order to improve optimistic validation method with the traditional techniques, a new technique has been proposed.

A new technique for the control of a weak shock discharged from a tube

2004 ◽  
Vol 218 (4) ◽  
pp. 377-387 ◽  
Author(s):  
H D Kim ◽  
Y H Kweon ◽  
T Aoki ◽  
T Setoguchi
Keyword(s):  
Peak Pressure ◽  
Impulsive Noise ◽  
Weak Shock ◽  
New Technique ◽  
Control Technique ◽  
Straight Tube ◽  
Human Beings ◽  
Impulsive Wave ◽  
A New Technique ◽  
Flow Devices

A shock wave discharged from a tube leads to an impulsive noise that is similar to a sonic boom. The impulsive noise has often been a major factor in deterioration of the performance of flow devices and has hazardous effects on human beings. The objective of the current work is to develop a new technique for the control of the impulsive wave. Experiments using a simple shock tube were carried out to investigate the effect of a cavity/helical vane system on the magnitude of an impulsive wave. The results showed that the magnitude of the impulsive wave was influenced by the detailed configuration of the helical vane inside the cavity which was installed at the exit of a tube. The results of the tests with and without the helical vane were compared to validate the effectiveness of the present control technique. The experimental data showed that the present cavity/helical vane system reduced the peak pressure of the impulsive wave up to about 50 per cent, compared with a straight tube, and was suitable for alleviating the magnitude of the impulsive wave.

Enhancing Vibration Damping of Smarts Structures by Energy Transfer between Modes

2014 ◽  
Vol 664 ◽  
pp. 341-345
Author(s):  
Zhen Wang ◽  
Claire Jean-Mistral ◽  
Simon Chesné ◽  
Luc Gaudiller
Keyword(s):  
Energy Transfer ◽  
Vibration Control ◽  
New Technique ◽  
Control Technique ◽  
Voltage Source ◽  
Low Power Consumption ◽  
Modal Control ◽  
A New Technique ◽  
Vibration Modal ◽  
Original Approach

In a context of embedded structures, the next challenge is to develop an efficient, energetically autonomous vibration control technique. Synchronized Switch Damping techniques (SSD) have demonstrated interesting properties in vibration control with a low power consumption. The damping attenuation can be improved thanks to energy transfer between a voltage source and the SSD circuit. Harvesting energy on a second structure can provide this voltage source but drastically complex the overall system. We propose here a new technique to enhance the classic SSD circuit due to energy harvesting. Our original approach consists in transferring energy between modes of a same structure: energy is harvested on non-controlled mode to increase the attenuation of a targeted mode. In this paper, we present theoretical analysis and numerical simulations of our energy-transfer architecture applied to an academic case, a free-clamped beam. Our electrical architecture called Synchronized Switching Damping and Harvesting (SSDH) is composed of a harvesting circuit (Synchronized Switch Harvesting on Inductor SSHI), a dc-dc converter (Buck-Boost topology) and a vibration modal control circuit (similar to a Synchronized Switch on Voltage SSDV). In a multi-sine excitation, an increase of the attenuation damping of 3.8dB with our new technique compared to classic SSDI is achieved.

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