Priority Heuristic in MDRTDBS

2019 ◽  
Vol 09 ◽  
Author(s):  
Prakash Kumar Singh ◽  
Udai Shanker
Keyword(s):  
System Performance ◽  
Concurrency Control ◽  
Data Item ◽  
Main Function ◽  
Quality Estimation ◽  
C Language ◽  
Heuristic Approaches ◽  
High Workload ◽  
Simulation Results ◽  
Real Time Database

Background: Mobile distributed real time database is an emerging field of research. Transaction execute in these system should commit before elapsing the deadline. Assigning priority to arrived and executing transaction is the main function of transaction scheduler. Perform correct order of execution enhance the system performance in time constraint environment. In recent years a number of heuristic policies in DRTDBS are developed to enhance the quality estimation of scheduler. However due to various wireless limitations a very little work is investigated in the MDRTDBS. In this paper we have develop two heuristic policies and perform simulation using pessimistic and optimistic concurrency control algorithm to enhance the system performance. Objective: Two heuristic policies based on write only locks and number of same data item existence has been introduced. These heuristic approaches enhance the performance of MDRTDBS scheduler. Method: Develop two heuristic policies based on data contention which cope with CC policies like DHP-2PL and FBOCC. These policies count the number of write only locks and existence of number of same data item. Ultimately these policies enhance the system performance. Results:: Investigated the performance using simulator which is designed using C language. Based on these simulation results using pessimistic and optimistic CCs different graphs are plotted which shows the performance of system for these developed heuristic approaches. During simulation the low and high workload of transaction arrival is taken to fair investigate of these heuristic approaches. Conclusion: Simulation results show that the system performance is improved using these heuristic approaches. However, NWL_Modified heuristic approach outperform in MDRTDBS than earlier heuristic approaches.

Shadow Sensitive SWIFT

2010 ◽  
pp. 130-150
Author(s):  
Udai Shanker ◽  
Abhay N. Singh ◽  
Abhinav Anand ◽  
Saurabh Agrawal
Keyword(s):  
Real Time ◽  
System Performance ◽  
Database Systems ◽  
Main Memory ◽  
Communication Delay ◽  
Data Item ◽  
Commit Protocols ◽  
Simulation Results ◽  
Real Time Database ◽  
Commit Protocol

This chapter proposes Shadow Sensitive SWIFT commit protocol for Distributed Real Time Database Systems (DRTDBS), where only abort dependent cohort having deadline beyond a specific value (Tshadow_creation_time) can forks off a replica of itself called a shadow, whenever it borrows dirty value of a data item. The new dependencies Commit-on-Termination external dependency between final commit operations of lender and shadow of its borrower and Begin-on-Abort internal dependency between shadow of borrower and borrower itself are defined. If there is serious problem in commitment of lender, execution of borrower is started with its shadow by sending YES-VOTE message piggy bagged with the new result to its coordinator after aborting it and abort dependency created between lender and borrower due to update-read conflict is reversed to commit dependency between shadow and lender with read-update conflict and commit operation governed by Commit-on-Termination dependency. The performance of Shadow Sensitive SWIFT is compared with shadow PROMPT, SWIFT and DSS-SWIFT commit protocols (Haritsa, Ramamritham, & Gupta, 2000; Shanker, Misra, & Sarje, 2006; Shanker, Misra, Sarje, & Shisondia, 2006) for both main memory resident and disk resident databases with and without communication delay. Simulation results show that the proposed protocol improves the system performance up to 5% as transaction miss percentage.

scholarly journals Evaluation of Transient Response of Different Earthing Configurations due to Lightning Impulses

2019 ◽  
Vol 8 (4) ◽  
pp. 6342-6346 ◽  
Keyword(s):  
Transient Response ◽  
System Performance ◽  
Electrical Equipment ◽  
Main Function ◽  
Soil Resistivity ◽  
Electrical Currents ◽  
The Past ◽  
The Earth ◽  
Simulation Results ◽  
Soil Ionization

Earthing system is very important in order to protect the electrical equipment as well as the human’s safety against over voltages. The main function of the earthling system is to remove unwanted excessive electrical currents caused by unusual conditions such as fault and lightning or switching over voltages by providing a low resistance path to the earth. Researchers had studied the behaviour of the earthling system to improve its performance for the past few years. There are few factors that influence the performance of the earthling system such as soil resistivity and soil ionization which need to be focused in order to improve the earthling. Thus, this paper evaluates on the factors that affect the behaviour of the earthling system based on simulation works using MATLAB and Safe Grid Software. Some analytical calculations are used to obtain the soil resistivity and resistance as well as the touch and step voltages. The simulation results were validated based on comparison with other studies on the factors that influence the earthling system performance. The results reveal that the variation of soil resistivity, the configuration of electrodes, current magnitude and frequency dependence can result in a change of transient response of the systems.

Concurrency control in mobile distributed real-time database systems

2000 ◽  
Vol 25 (4) ◽  
pp. 261-286 ◽  
Author(s):  
Kam-Yiu Lam ◽  
Tei-Wei Kuo ◽  
Wai-Hung Tsang ◽  
Gary C.K Law
Keyword(s):  
Real Time ◽  
Concurrency Control ◽  
Database Systems ◽  
Real Time Database

scholarly journals Comparative Analysis and Design of the Shielding Techniques in WPT Systems for Charging EVs

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2115 ◽  
Author(s):  
Linlin Tan ◽  
Kamal Eldin Idris Elnail ◽  
Minghao Ju ◽  
Xueliang Huang
Keyword(s):  
Finite Element Method ◽  
Electric Vehicles ◽  
System Performance ◽  
Human Exposure ◽  
System Efficiency ◽  
Shielding Effectiveness ◽  
Wireless Power ◽  
Analysis And Design ◽  
Reactive Current ◽  
Simulation Results

Wireless power transfer (WPT) systems for charging Electric Vehicles (EVs) have gained extensive attention due to their many advantages. However, human exposure to electromagnetic fields (EMFs) has become a serious concern in high-power cases. In this paper, shielding techniques, including magnetic, metallic, and resonant reactive current shields, are investigated. Finite element method software is used to evaluate and compare the shielding effectiveness, charger weight, and system performance. The results show that the resonant reactive current shielding has a low EMF level with reasonable system efficiency and acceptable charger weight. In addition, 5 kW with 15 cm air gap WPT chargers were built to validate the simulation results.

Research and Implement of an Improved Frame-Slotted ALOHA Anti-Collision Algorithm

2014 ◽  
Vol 945-949 ◽  
pp. 2519-2522
Author(s):  
Li He ◽  
Gai Ping Liu ◽  
Chuan Yuan Han
Keyword(s):  
System Throughput ◽  
Slotted Aloha ◽  
C Language ◽  
Key Technology ◽  
Rfid System ◽  
Simulation Results

The anti-collision algorithm is the key technology of RFID system. Firstly, this paper studied frame-slotted ALOHA anti-collision algorithm, in order to solve the shortcomings of ALOHA algorithm, an improved anti-collision algorithm is proposed based on grouping mechanism, and it also carried out the simulation experiences using the C# language under the .NET platform. The simulation results indicate that the improved algorithms can increase RFID system throughput.

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