scholarly journals Satellite-Aided Consensus Protocol for Scalable Blockchains

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5616
Author(s):  
Xintong Ling ◽  
Zheng Gao ◽  
Yuwei Le ◽  
Li You ◽  
Jiaheng Wang ◽  
...  
Keyword(s):  
Model Simulation ◽  
Network Capacity ◽  
Propagation Delay ◽  
Information Propagation ◽  
Consensus Protocol ◽  
Capacity Limits ◽  
Extensive Coverage ◽  
Working Principle ◽  
Simulation Results ◽  
The Impact

In this work, we propose a satellite-aided permissionless consensus protocol for scalable space–terrestrial blockchains. We design its working principle and workflow by taking full advantage of satellites for extensive coverage and ubiquitous connectivity. Based on the proposed protocol, we demonstrate how such a space–terrestrial blockchain grows and evolves through several typical cases in the presence of adversarial nodes, user misbehavior, and transmission outage. Taking proof of work (PoW) as a benchmark, we assess the system security by considering both adversarial miners and possible colluding satellites. Then, we analyze the maximum blockchain throughput under network capacity limits and evaluate the impact of information propagation delay via a Markov model. Simulation results support that the proposed satellite-aided consensus protocol achieves higher throughput and exhibits greater scalability than PoW.

Investigation on penetration model of shaped charge jet in water

2016 ◽  
Vol 30 (02) ◽  
pp. 1550268 ◽  
Author(s):  
Jinwei Shi ◽  
Xingbai Luo ◽  
Jinming Li ◽  
Jianwei Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Model Simulation ◽  
Theoretical Models ◽  
Theoretical Research ◽  
Water Medium ◽  
Simulation Results ◽  
Jet Penetration ◽  
The Impact ◽  
Penetration Velocity

To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine–Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

Analysis of Dynamic Characteristics of Automatic Transmission Shifting Control

2014 ◽  
Vol 643 ◽  
pp. 42-47 ◽  
Author(s):  
Yan Xiao Fu ◽  
Liang Yi Cui ◽  
Xiang Yang Xu ◽  
Peng Dong
Keyword(s):  
Simulation Model ◽  
Control Strategy ◽  
Model Simulation ◽  
Automatic Transmission ◽  
Test Results ◽  
Shift Quality ◽  
Impact Function ◽  
Automatic Transmissions ◽  
Simulation Results ◽  
The Impact

Basing on the fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. The transmitted torque of the oncoming shift elements before synchronization point can be reduced by an impact function in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with an accurate dynamic model, simulation results and test results are neighborhood data, the simulation model can be used to help realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.

scholarly journals Reforming Spending Policy and Its Impact on Indonesia’s Economy: The Case of Fuel Subsidy and Infrastructure

2019 ◽  
Vol 20 (1) ◽  
pp. 12-27
Author(s):  
Muhammad Anas
Keyword(s):  
Economic Activity ◽  
Model Simulation ◽  
Social Accounting Matrix ◽  
Sectoral Output ◽  
Long Run ◽  
Simulation Results ◽  
Economic Infrastructure ◽  
The Government ◽  
The Impact

The quality of Indonesia’s infrastructure up until 2014 was considered uncompetitive, and one of the reasons was that there was not enough money spent on infrastructure, and too much on fuel subsidy. In November 2014, the government of Indonesia decided to cut the expenditure for fuel subsidy and reallocate the money to invest on public services. This study was conducted with the intention to quantify the impact of the program on economic growth and income distribution in Indonesia using Social Accounting Matrix (SAM) model. Simulation results indicated that the impact from social and human capital infrastructure was bigger than that of economic infrastructure, although the simulation for both categories resulted in an increase of sectoral output and domestic income. Therefore, improving infrastructure, especially social, is vital to stimulate economic activity in the long run.

scholarly journals The Impact of Underground Logistics System on Urban Sustainable Development: A System Dynamics Approach

2019 ◽  
Vol 11 (5) ◽  
pp. 1223 ◽  
Author(s):  
Jianjun Dong ◽  
Yuanxian Xu ◽  
Bon-gang Hwang ◽  
Rui Ren ◽  
Zhilong Chen
Keyword(s):  
Sustainable Development ◽  
System Dynamics ◽  
Urban Transportation ◽  
Network Capacity ◽  
Urban Traffic ◽  
Beijing City ◽  
Logistics System ◽  
Urban Sustainable Development ◽  
Simulation Results ◽  
The Impact

The lack of practical application and accurate benefit analysis, which are the prerequisites for each other, make it difficult to implement and promote the underground logistics system (ULS), although in theory people always recognize its advantages in sustainable improvement of urban transportation and logistics. This paper attempts to use the system dynamics (SD) method, based on the real-world simulation, to analyze the quantitative relationship between the implementation strategy of ULS and the sustainability of urban transportation and logistics to solve this problem. Beijing city, China, was selected as the empirical background. Four ULS implementation strategies were proposed according to the city’s potential investment in ULS and its demand for ULS network capacity. Meanwhile, four representative indicators were selected to evaluate the simulation results, including the average speed of the road networks in the peak hour, congestion loss, delivery travel time in the peak hour and the PM emissions of the truck. Good fitting index of historical data shows the validity of the model. Simulation results show that ULS, as a supplement to the urban integrated transport system, can significantly improve urban traffic and logistics. This study provides a perspective in the systematic and quantitative analysis of ULS to support the urban sustainable development.

scholarly journals The Effectiveness of Vaccination Against The Spread of COVID-19 with SEIR Mathematical Modeling in Gowa District

Jurnal Varian ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 17-28
Author(s):  
Syafruddin Side ◽  
Putri Kharina Mahathir Hulinggi ◽  
Husnul Khatimah Syam ◽  
Muhammad Irfan ◽  
Andi Gagah Palarungi Taufik ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Literature Review ◽  
Model Simulation ◽  
Research Result ◽  
Mapping Model ◽  
Simulation Results ◽  
The Impact

The spread of disease in epidemic range, endemic range, as well as in the pandemic range that is spreading of the disease can be stopped with getting vaccinated. The vaccines that are effective and efficient can be the missile that stopped this Covid-19 pandemic. The aim of this research is to (1) know the mapping model of mathematics SEIR in distributing vaccines toward the spread of Covid-19 in Kabupaten Gowa, (2) know the analysis and model simulation of mathematics SEIR in distributing vaccine toward the spread of Covid-19 in Kabupaten Gowa, also (3) know the impact of distributing vaccine toward the spread of Covid-19 in Kabupaten Gowa. The method we used is the literature review, the collecting data obtained by an interview and documentation review. The research result discovered that the model of mathematics SEIR is used to describe the distribution of vaccines toward the spread of Covid-19 in Kabupaten Gowa. The analysis and simulation results model of mathematics SEIR showed that the higher vaccines effectiveness and the number of the population in Kabupaten Gowa that already had vaccinated is higher, then showed no more spreads of Covid-19 and the pandemic is over.

scholarly journals Quantifying the Effects of Urbanization on Floods for two adjacent basins in Shenzhen and Hong Kong, China.

2021 ◽  
Author(s):  
Dandan Liu ◽  
Yiheng Chen ◽  
Jinhui Huang ◽  
Xiaogang Shi
Keyword(s):  
Hong Kong ◽  
Model Simulation ◽  
Flood Events ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Impervious Area ◽  
The Future ◽  
Urbanization Development ◽  
Simulation Results ◽  
The Impact

<p>With the accelerating urbanization in developing countries, the threats of extreme rainfall and flood events are increasing. The impact of flood disasters severely threatens the safety of cities with a huge population. In order to quantitatively study the impact of urbanization development on urban floods, the hydrological characteristics of two adjacent basins will be analyzed and compared in this study -- Shenzhen, China with rapid urbanization in the past 40 years, and Hong Kong, China that was already urbanized.</p><p>The methods of this study mainly include the following two points. Firstly, in order to clarify the urbanization development process of the study regions, the geospatial database of surface impervious area of two adjacent basins from 1986 to 2018 was obtained in this study. In addition, this study intends to predict the impervious area of the study area in the future years through urban planning. The prediction method is based on adaptive cell deep learning analysis method. Secondly, in order to simulate the waterlogging situation in the two regions, this study intends to select specific flood events to establish and calibrate the SWMM model. By changing the impervious area of the two regions, hydrological parameters such as surface runoff and sensitivity under different scenarios can be obtained.</p><p>After model simulation, we will finally analyze the simulation results as follows: Firstly, the variation of runoff and flood peak with impervious area will be analyzed; Secondly, by comparing the simulation results of the two regions, the sensitivity of flood events to urbanization development will be evaluated; Finally, according to the predicted simulation results, the flood situation in the study area will be evaluated in the future years, which has a certain guiding significance for urban flood prevention.</p>

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.

A Dicode Signaling Scheme for Capacitively Coupled Interface

2011 ◽  
Vol 497 ◽  
pp. 296-305
Author(s):  
Yasushi Yuminaka ◽  
Kyohei Kawano
Keyword(s):  
Partial Response ◽  
Data Transmission ◽  
High Speed ◽  
Circuit Simulation ◽  
Frequency Bandwidth ◽  
Capacitively Coupled ◽  
Limited Frequency ◽  
Simulation Results ◽  
Response Coding ◽  
The Impact

In this paper, we present a bandwidth-efficient partial-response signaling scheme for capacitivelycoupled chip-to-chip data transmission to increase data rate. Partial-response coding is knownas a technique that allows high-speed transmission while using a limited frequency bandwidth, by allowingcontrolled intersymbol interference (ISI). Analysis and circuit simulation results are presentedto show the impact of duobinary (1+D) and dicode (1-D) partial-response signaling for capacitivelycoupled interface.

An Improved Initial Alignment Method of Strap-Down Inertial Navigation System on a Swaying Base

2013 ◽  
Vol 415 ◽  
pp. 143-148
Author(s):  
Li Hua Zhu ◽  
Xiang Hong Cheng
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Alignment Algorithm ◽  
Alignment Method ◽  
Initial Alignment ◽  
Vehicle Simulation ◽  
Robust Property ◽  
Simulation Results ◽  
Lever Arm Effect ◽  
The Impact

The design of an improved alignment method of SINS on a swaying base is presented in this paper. FIR filter is taken to decrease the impact caused by the lever arm effect. And the system also encompasses the online estimation of gyroscopes’ drift with Kalman filter in order to do the compensation, and the inertial freezing alignment algorithm which helps to resolve the attitude matrix with respect to its fast and robust property to provide the mathematical platform for the vehicle. Simulation results show that the proposed method is efficient for the initial alignment of the swaying base navigation system.

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