scholarly journals Adjusting the Block Interval in PoW Consensus by Block Interval Process Improvement

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2135
Author(s):  
Heesang Kim ◽  
Dohoon Kim
Keyword(s):  
Network Security ◽  
Process Improvement ◽  
Critical Issue ◽  
Consensus Algorithm ◽  
Difficulty Level ◽  
Similar Improvement ◽  
Time Required

Blockchain is not widely applied in various fields due to the critical issue of scalability as part of the blockchain trilemma. This issue arises during consensus among the nodes in a public blockchain. To address the issue of low scalability with proof-of-work (PoW) consensus, various methods have been proposed for transaction per second (TPS) improvement. However, no such methods include an improvement in the consensus step. Therefore, to improve PoW public blockchain scalability, it is important to shorten the time required for PoW consensus. This paper proposes a method for minimizing the block intervals that occur during consensus over a PoW blockchain network. A shortened block interval leads to an increase in the probability of three different attacks: selfish mining, double-spending, and eclipse attacks. According to an experiment using Ethereum, with a typical PoW blockchain, it is inevitable to provide rewards for stable block mining in competition between mining pools. To find an optimal block interval in the PoW consensus algorithm, we conducted a four-step experiment. The purpose of this experiment was to verify the difficulty level and issues with Mainnet security. Therefore, considering stale block mining rewards, an optimal block interval is proposed. The Ethereum TPS was improved by at least 200%. Given this finding, it is considered possible to achieve a similar improvement in a different PoW blockchain. On balance, even if the block interval is shorter than that of the PoW Mainnet, network security falls by only 1.21% in Testnet, even with a rise in the stale block rate, while performance is increased at up to 120 TPS, which is three times higher than that in Mainnet.

scholarly journals A Double Swath Configuration for Improving Throughput and Accuracy of Trait Estimate from UAV Images

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenjuan Li ◽  
Alexis Comar ◽  
Marie Weiss ◽  
Sylvain Jay ◽  
Gallian Colombeau ◽  
...  
Keyword(s):  
Plant Height ◽  
Precision Agriculture ◽  
Focal Length ◽  
Critical Issue ◽  
Quality Level ◽  
Ground Sample ◽  
Height Estimates ◽  
Uav Images ◽  
Time Required ◽  
Multispectral Camera

Multispectral observations from unmanned aerial vehicles (UAVs) are currently used for precision agriculture and crop phenotyping applications to monitor a series of traits allowing the characterization of the vegetation status. However, the limited autonomy of UAVs makes the completion of flights difficult when sampling large areas. Increasing the throughput of data acquisition while not degrading the ground sample distance (GSD) is, therefore, a critical issue to be solved. We propose here a new image acquisition configuration based on the combination of two focal length (f) optics: an optics with f=4.2 mm is added to the standard f=8 mm (SS: single swath) of the multispectral camera (DS: double swath, double of the standard one). Two flights were completed consecutively in 2018 over a maize field using the AIRPHEN multispectral camera at 52 m altitude. The DS flight plan was designed to get 80% overlap with the 4.2 mm optics, while the SS one was designed to get 80% overlap with the 8 mm optics. As a result, the time required to cover the same area is halved for the DS as compared to the SS. The georeferencing accuracy was improved for the DS configuration, particularly for the Z dimension due to the larger view angles available with the small focal length optics. Application to plant height estimates demonstrates that the DS configuration provides similar results as the SS one. However, for both the DS and SS configurations, degrading the quality level used to generate the 3D point cloud significantly decreases the plant height estimates.

Penetration Testing and Security Assessment of Healthcare Records on Hospital Websites

2020 ◽  
Vol 10 (9) ◽  
pp. 2242-2246
Author(s):  
Tian Tang ◽  
Mu-Chuan Zhou ◽  
Yi Quan ◽  
Jun-Liang Guo ◽  
V. S. Balaji ◽  
...  
Keyword(s):  
Network Security ◽  
Computer Security ◽  
Denial Of Service ◽  
Critical Issue ◽  
Security Threats ◽  
Security Assessment ◽  
It Industry ◽  
Penetration Testing ◽  
Industry Sector ◽  
The Web

At present, computer security is the flourishing field in the IT industry. Nowadays, the usage of computers and the Internet grows drastically, and hence, computers become vehicles for the attackers to spread viruses and worms, to distribute spam and spyware, and to perform denial-of-service attacks, etc. The IT engineers (even users) should know about network security threats, and at the same time, to some extent, they should know techniques to overcome the issues. The reliability and privacy of healthcare records of the patients are the most critical issue in the healthcare business industry sector. The security safeguards, such as physical, technical, and administrative safeguards, are crucial in protecting the information in all aspects. This article deals with the forty popular hospital portals in India related to the professional and network security related issues such as operating system guesses, number of open/closed/filtered ports, the name of the Web server, etc. The Nmap (network mapper) tool is used to analyze the results belong to the security perspective.

A Slim Sector Model for the Analysis of Fatigue Life of Fine Pitch Flip Chip Packages

2005 ◽  
Author(s):  
Bing Zhao ◽  
Andrew A. O. Tay
Keyword(s):  
Fatigue Life ◽  
Flip Chip ◽  
Computation Time ◽  
Critical Issue ◽  
Temperature Cycling ◽  
Element Analysis ◽  
Sector Model ◽  
Fine Pitch ◽  
Time Required ◽  
Diagonal Plane

In the near future, it is likely that the interconnection pitch of flip chips will fall below 100 microns. For a flip chip of 20mm × 20mm at this pitch, there will be 40,000 interconnections on the chip. Even after taking advantage of symmetry whereby only a one-eighth model need be analyzed, there will be 5,000 interconnections. If solder were used to form the interconnection, plasticity and creep effects would need to be taken into account. Despite the great advances in computer technology, the computer memory and computation time required for a full 3D finite element analysis (FEA) of such a fine-pitch IC package is prohibitive. This paper presents a slim sector model which could be used to overcome this problem. Essentially, a slim sector of the package adjacent to the diagonal is analyzed rather than a 1/8 model. The appropriate boundary condition to be applied to the slim sector model is a critical issue. With the large number of interconnections, it is reasonable to expect that the displacement of points close to the diagonal plane of the package will tend to be directed radially outwards from the neutral point at the centre of the package. The validity of this assumption was investigated by performing a full 3D FEA of the 1/8 model of two flip chip packages of dimensions 4mm square and 6mm square. A few slim sector models have been developed and their accuracy and computational efficiency studied. The fatigue life of the critical solder joint was determined by performing a temperature cycling simulation between −40C and 150C. The elastoplastic and creep properties of solder were taken into account. As the 1/8 model is the most accurate model, its results were taken as reference. It was found that the accuracy of the best slim sector model ranged between 12% and 27%. A comparison was also made between the slim sector model and the popular strip model. It was found that the slim sector model was much more accurate than the strip model which gives error of 61–248%.

scholarly journals An Effective Randomization Framework to POW Consensus Algorithm of Blockchain (RPoW)

2019 ◽  
Vol 8 (6) ◽  
pp. 1793-1797
Keyword(s):  
Electric Power ◽  
Execution Time ◽  
Network Architecture ◽  
Consensus Algorithm ◽  
Instruction Set ◽  
Decentralized System ◽  
Blockchain Technology ◽  
The World ◽  
Consensus Procedure ◽  
Time Required

Blockchain technology has become a buzzword due to its intuitive applications and its decentralized network architecture. Blockchain is a decentralized system that uses peer -to - peer networking and appropriate consensus algorithm for secure and reliable transactions and records them all in an immutable ledger as chain of blocks. The world got introduced to the blockchain technology, when Satoshi Nakamoto released Bitcoin in 2009[2]. Though this technology is famous for being the backbone of cryptocurrencies, it has got into various industry domains and many applications have been developed using blockchain [11]. The consensus algorithm used in Blockchain architecture influences how agreement is made to add a new block among all the nodes in the network. PoW (Proof of work) is the consensus algorithm applied in the Bitcoin network architecture and many other blockchain applications. PoW requires each node to solve a cryptographic puzzle with adjusted difficulty, to get the privilege to add a new block to the current chain. The first node that solves the puzzle will have this privilege and some reward. Proof-of-Work (PoW) uses extensive amounts of electric power and steep computing hardware as an effect of their consensus procedure [1]. This proposed work presents an effective randomization framework that reduces the execution time required to calculate the hash value. The number of instruction-set required to compute the PoW consensus is also reduced. This approach helps in maintaining a fair decentralized network to construct blockchain applications.

scholarly journals Query Optimization in a Blockchain-Based Land Registry Management System

2021 ◽  
Vol 26 (1) ◽  
pp. 13-21
Author(s):  
Amrendra Singh Yadav ◽  
Dharmender Singh Kushwaha
Keyword(s):  
Network Architecture ◽  
Hash Table ◽  
Search Time ◽  
Consensus Algorithm ◽  
Decentralized System ◽  
Blockchain Technology ◽  
Time Required ◽  
Technical Discussion ◽  
Search Approach ◽  
Land Records

Digitization of land records is not sufficient for preventing fraud cases, time delay, and brokers' involvement. Distributed Ledger Technology (DLT) is used for making this digitized record more secure and process it in a decentralized way, and reduces paperwork in selling and buying of land. Blockchain technology has come to the fore in recent years and is the center of technical discussion, with intuitive applications driven by its network architecture. It has been firmly established as one of the most important emerging technologies. This article aims to implement a land registry mechanism using blockchain technology and optimize searching of land records in blockchain. Interplanetary File System (IPFS) provides an infrastructure that offers a precise portrayal of all the members' roles. The application interacts with the blockchain network, which is built using IPFS. This paper will help in providing a secure and decentralized system for the land registry process. The proposed consensus algorithm MRRCM achieves less time required to generated a block on an average by 3.06% round-robin and 96.48% PoW approach. The proposed modified hash table search approach requires less time to search the blockchain's land record block than the extensive liner searches and hash table search approach. A search for a land record in the blockchain reduces the search time on an average by 59.5% compared to the traditional extensive liner search approach and by 18.68% as compared with the hash table search approach.

scholarly journals In Situ Team-Based Simulation Training to Close the Loop on Event Reporting

2021 ◽  
pp. 6-11
Author(s):  
Caoimhe Duffy ◽  
William Yi ◽  
Joshua Atkins
Keyword(s):  
Data Collection ◽  
Adverse Events ◽  
Process Improvement ◽  
Simulation Training ◽  
Mandated Reporting ◽  
Effect Change ◽  
Event Reporting ◽  
Aggregated Data ◽  
Time Required

Reporting adverse events is often stigmatized in medicine. Adverse events are underreported. Underreporting has been linked to fear, the time required to complete a report, and a belief that reporting may not result in improvement.1 The reluctance to report is multidimensional and may relate to guilt, fear of punishment of self or others, fear of embarrassment, fear of litigation, and lack of confidence to effect change. Central to this fear is the widely held belief that errors and adverse events are due to carelessness and that blame must be assigned—often to the provider “at fault” or at the sharp end of the process. However, reporting of events offers an invaluable opportunity to identify latent systems issues and review and redesign error-trapping procedures and workflows. Without measurement, it is challenging to leverage adverse events as catalysts for targeted process improvement. Mandated reporting at the state and national levels is an influential catalyst to enhance data collection of adverse events. Aggregated data across varied practice settings are powerful. Mandated reporting alleviates some of the fear associated with reporting and increases reporting volume and relevance.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Search mode for rapid detection of virus particles

1991 ◽  
Vol 49 ◽  
pp. 286-287
Author(s):  
O. E. Bradfute
Keyword(s):  
Electron Microscopy ◽  
Rapid Detection ◽  
Plant Virus ◽  
Low Dose ◽  
Search Mode ◽  
Virus Diseases ◽  
Virus Particles ◽  
Focus Image ◽  
Time Required ◽  
Rapid Switching

Electron microscopy is frequently used in preliminary diagnosis of plant virus diseases by surveying negatively stained preparations of crude extracts of leaf samples. A major limitation of this method is the time required to survey grids when the concentration of virus particles (VPs) is low. A rapid survey of grids for VPs is reported here; the method employs a low magnification, out-of-focus Search Mode similar to that used for low dose electron microscopy of radiation sensitive specimens. A higher magnification, in-focus Confirm Mode is used to photograph or confirm the detection of VPs. Setting up the Search Mode by obtaining an out-of-focus image of the specimen in diffraction (K. H. Downing and W. Chiu, private communications) and pre-aligning the image in Search Mode with the image in Confirm Mode facilitates rapid switching between Modes.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Clinical Update: Functional Capacity Evaluations—An Update

1999 ◽  
Vol 4 (5) ◽  
pp. 4-7 ◽  
Author(s):  
Laura Welch
Keyword(s):  
Job Performance ◽  
Functional Capacity ◽  
Injury Risk ◽  
Disability Evaluation ◽  
Time Period ◽  
Submaximal Effort ◽  
Lack Of Sleep ◽  
Overall Performance ◽  
Time Required ◽  
Specific Limitation

Abstract Functional capacity evaluations (FCEs) have become an important component of disability evaluation during the past 10 years to assess an individual's ability to perform the essential or specific functions of a job, both preplacement and during rehabilitation. Evaluating both job performance and physical ability is a complex assessment, and some practitioners are not yet certain that an FCE can achieve these goals. An FCE is useful only if it predicts job performance, and factors that should be assessed include overall performance; consistency of performance across similar areas of the FCE; consistency between observed behaviors during the FCE and limitations or abilities reported by the worker; objective changes (eg, blood pressure and pulse) that are appropriate relative to performance; external factors (illness, lack of sleep, or medication); and a coefficient of variation that can be measured and assessed. FCEs can identify specific movement patterns or weaknesses; measure improvement during rehabilitation; identify a specific limitation that is amenable to accommodation; and identify a worker who appears to be providing a submaximal effort. FCEs are less reliable at predicting injury risk; they cannot tell us much about endurance over a time period longer than the time required for the FCE; and the FCE may measure simple muscular functions when the job requires more complex ones.

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