scholarly journals Modeling of SPERT IV Reactivity Initiated Transient Tests in EUREKA-2/RR Code

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
N. H. Badrun ◽  
M. H. Altaf ◽  
M. A. Motalab ◽  
M. S. Mahmood ◽  
M. J. H. Khan
Keyword(s):  
Flow Condition ◽  
Peak Power ◽  
Coolant Temperature ◽  
Energy Agency ◽  
Positive Reactivity ◽  
Simulation Results ◽  
Experimental Values ◽  
Initial Power ◽  
Scram System ◽  
Present Simulation

EUREKA-2/RR code has been used for SPERT IV reactor benchmark calculations against the experimental results provided by IAEA (International Atomic Energy Agency) obtained for a series of transient tests initiated by step insertion of different magnitudes of positive reactivity with varying degrees of different controlled parameters such as reactor initial power, coolant temperature and coolant flow condition. 20 out of 39 tests that fall under forced convection mode have been considered for the present simulation provided the reactor scram system is disabled. Peak power and peak clad temperature due to transient have been calculated and it was found that although peak clad temperature values agreed, the peak power values seem to underestimate the experimental values. Further study appears to be needed to identify the limitations in modeling or examining the effect of input parameters during modeling to obtain the better simulation results.

The Ship Track Keeping With Roll Reduction Using a Multiple-States PD Controller on the Rudder Operation

2008 ◽  
Vol 45 (01) ◽  
pp. 21-27
Author(s):  
Ming-Chung Fang ◽  
Jhih-Hong Luo
Keyword(s):  
Numerical Model ◽  
Line Of Sight ◽  
Pd Controller ◽  
Input Multiple Output ◽  
Maneuvering In Waves ◽  
Single Input ◽  
Reduction Function ◽  
Simulation Results ◽  
Guidance Technique ◽  
Present Simulation

The paper presents a nonlinear hydrodynamic numerical model with multiple-states proportional-derivative (PD) controllers for simulating the ship's tracking in random sea. By way of the rudder operation, the track-keeping ability of the PD controller on the ship is examined using the line-of-sight (LOS) guidance technique. Furthermore, the roll-reduction function using the rudder control is also included in the PD controller. From the present simulation results, the single-input multiple-output (SIMO) heading/roll PD controller including LOS technique developed here indeed works, either for the roll reduction or for track keeping while the ship is maneuvering in waves.

Idle Users Management for Improved BitTorrent Performance

2010 ◽  
Vol 439-440 ◽  
pp. 859-864
Author(s):  
Ming Zhang ◽  
Jin Qiu Yang
Keyword(s):  
Content Delivery ◽  
The Internet ◽  
Huge Amount ◽  
The Past ◽  
Internet Users ◽  
Communication Paradigm ◽  
Bittorrent Protocol ◽  
Simulation Results ◽  
Present Simulation ◽  
Steady State Performance

In the past few years, there have been tremendous interest in the peer-to-peer(P2P) content delivery. This communication paradigm dramatically increases the traffic over inter-ISP links. In particular, BitTorrent(BT), the most popular P2P application, generates a huge amount of traffic on the Internet. BitTorrent’s performance is limited by the fact that typical internet users have much lower upload bandwidths than download bandwidths. This results in the overall average download speed of a BitTorrent-like file download system to be bottle-necked by the much lower upload capacity. We think about to utilize idle users’ spare upload capacity to largely improve the download speed beyond what can be achieved in a conventional BitTorrent network. In this paper, we design a system that is completely compatible with the already existing clients who conform to the BitTorrent protocol, at the same time, we analyze this system’s steady-state performance and present simulation results.

Numerical Simulation on Temperature Distributions to Cold Store

2012 ◽  
Vol 217-219 ◽  
pp. 1460-1464 ◽  
Author(s):  
Jing Xie ◽  
Yi Tang ◽  
Jin Feng Wang ◽  
Chen Miao ◽  
Yong Yan Lin
Keyword(s):  
Numerical Simulation ◽  
Simple Algorithm ◽  
Simulation Method ◽  
Calculation Error ◽  
Cooling Process ◽  
Temperature Distributions ◽  
Cold Store ◽  
Simulation Results ◽  
Experimental Values ◽  
Simulation Condition

On the basis of previous work, the simulation condition of cold store was improved to reduce calculation error. The SIMPLE algorithm and Boussineq assumption were used and the turbulent intensity was also set. The numerical simulation results reflected that the temperature distribution was closer to the previous experimental results after using new method. The error between simulation values and experimental values was decreased. The simulation result showed that temperature of corner was highest in the cold store. The temperature change of the cold store in the cooling process could be better predicted by using modified simulation method and the accuracy of numerical simulation of cold store in the cooling process could also be validated.

EFFECTIVE DATA DISSEMINATION FOR INFORMATION SHARING BASED ON INTER-VEHICLE COMMUNICATION

2007 ◽  
Vol 08 (04) ◽  
pp. 337-354 ◽  
Author(s):  
HIROYUKI SAGO ◽  
MASAKO SHINOHARA ◽  
TAKAHIRO HARA ◽  
SHOJIRO NISHIO
Keyword(s):  
Information Sharing ◽  
Data Dissemination ◽  
Data Availability ◽  
Intelligent Transport System ◽  
Intelligent Transport ◽  
Vehicle Communication ◽  
Route Information ◽  
Simulation Results ◽  
Near Future ◽  
Present Simulation

In an Intelligent Transport System (ITS), information sharing based on inter-vehicle communication is effective for improving data availability. In this paper, we propose a data dissemination method for sharing data items among vehicles, which increases the opportunity for vehicles to acquire more fresh data items that users request. In our proposed method, vehicles are grouped according to their locations, and movement directions that are estimated from their route information. Then, data items that are more likely to be accessed in the near future are disseminated between two groups. We also present simulation results to evaluate the performance of our proposed method.

scholarly journals Approximate Image Reconstruction in Landscape Reflection Imaging

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Rémi Régnier ◽  
Gaël Rigaud ◽  
Maï K. Nguyen
Keyword(s):  
Inverse Problem ◽  
Image Reconstruction ◽  
Inversion Formula ◽  
Imaging Modality ◽  
Reconstruction Algorithm ◽  
Reflectivity Function ◽  
Reconstruction Kernel ◽  
Simulation Results ◽  
Reflection Imaging ◽  
Present Simulation

Simple reflection imaging of landscape (scenery or extended objects) poses the inverse problem of reconstructing the landscape reflectivity function from its integrals on some particular family of spheres. Such data acquisition is encoded in the framework of a Radon transform on this family of spheres. In spite of the existence of an exact inversion formula, the numerical landscape reflectivity function reconstitution is best obtained with an approximate but judiciously chosen reconstruction kernel. We describe the working of this reflection imaging modality and its theoretical handling, introduce an efficient and stable image reconstruction algorithm, and present simulation results to prove the validity of this choice as well as to demonstrate the feasibility of this imaging process.

scholarly journals Vaccinations or Non-Pharmaceutical Interventions:Safe Reopening of Schools in England

2021 ◽  
Author(s):  
Carolina Cuesta-Lazaro ◽  
Arnau Quera-Bofarull ◽  
Joseph Aylett-Bullock ◽  
Bryan N. Lawrence ◽  
Kevin Fong ◽  
...  
Keyword(s):  
Real World ◽  
Positive Impact ◽  
Adult Population ◽  
Vaccination Campaign ◽  
Age Group ◽  
School Based ◽  
Simulation Results ◽  
The Individual ◽  
Present Simulation ◽  
Pharmaceutical Interventions

With high levels of the Delta variant of COVID-19 circulating in England during September 2021, schools are set to reopen with few school-based non-pharmaceutical interventions (NPIs). In this paper, we present simulation results obtained from the individual-based model, JUNE, for school opening after a prior vaccination campaign using an optimistic set of assumptions about vaccine efficacy and the likelihood of prior-reinfection. We take a scenario-based approach to modelling potential interventions to assess relative changes rather than real-world forecasts. Specifically, we assess the effects of vaccinating those aged 16-17, those aged 12-17, and not vaccinating children at all relative to only vaccinating the adult population. Vaccinating children in the 12-15 age group would have had a significant impact on the course of the epidemic, saving thousands of lives overall in these simulations. In the absence of such a vaccination campaign our simulations show there could still be a significant positive impact on the epidemic (fewer cases, fewer deaths) by continuing NPI strategies in schools. Our analysis suggests that the best results are likely derived from a combination of vaccinations and NPIs.

scholarly journals The case of muddled units in temporal discounting

2018 ◽  
Author(s):  
Benjamin Thomas Vincent ◽  
Neil Stewart
Keyword(s):  
Delay Discounting ◽  
Power Law ◽  
Temporal Discounting ◽  
Hyperbolic Discounting ◽  
Cognitive Models ◽  
Units Of Measurement ◽  
The Future ◽  
Simulation Results ◽  
Present Simulation

While parameters are crucial components of cognitive models, relatively little importance has been given to their units. We show that this has lead to some parameters to be contaminated, introducing an artifactual correlation between them. We also show that this has led to the illegal comparison of parameters with different units of measurement – this may invalidate parameter comparisons across partic- ipants, conditions, groups, or studies. We demonstrate that this problem affects two related models: Stevens’ Power Law and Rachlin’s delay discounting model. We show that it may even affect models which superficially avoid the incompatible units problem, such as hyperbolic discounting. We present simulation results to demonstrate the extent of the issues caused by the muddled units problem. We offer solutions in order to avoid the problem in the future or to aid in re-interpreting existing datasets.

scholarly journals Implementation of a neuron model using FPGAS

2003 ◽  
Vol 1 (03) ◽  
Author(s):  
M. A. Bañuelos-Saucedo ◽  
J. Castillo-Hernández ◽  
S. Quintana-Thierry ◽  
R. Damián-Zamacona ◽  
J. Valeriano-Assem ◽  
...  
Keyword(s):  
Neuron Model ◽  
Parallel Architecture ◽  
Recognition System ◽  
Activation Function ◽  
Control Problems ◽  
Digital Implementation ◽  
Field Programmable ◽  
Simulation Results ◽  
And Control ◽  
Present Simulation

Artificial neural networks base their processing capabilities in a parallel architecture, and this makes them useful to solve pattern recognition, system identification, and control problems. In this paper, we present a FPGA (Field Programmable Gate Array) based digital implementation of a McCulloch-Pitts type of neuron model with three types of non-linear activation function: step, ramp-saturation, and sigmoid. We present the VHDL language code used to implement the neurons as well as to present simulation results obtained with Xilinx Foundation 3.0 software. The results are analyzed in terms of speed and percentage of chip usage.

Sensitivity Analysis for Release and Transport Behavior of Radionuclide of the 1F Unit-1 Accident Using SAMPSON

2020 ◽  
Author(s):  
Chiaki Kino ◽  
Hidetoshi Karasawa ◽  
Shunsuke Uchida
Keyword(s):  
Sensitivity Analysis ◽  
Hydrogen Iodide ◽  
Fuel Pellet ◽  
Chemical Forms ◽  
Deposition Velocities ◽  
Radionuclide Distribution ◽  
Simulation Results ◽  
Release Model ◽  
Present Simulation ◽  
Reactor Pressure

Abstract To support the 1F decommissioning project, the Institute of Applied Energy has been analyzing the course of the accident using the SAMPSON code with an aim to grasp radionuclide distribution in 1F NPP. The present study has mainly focused on molybdenum release from a fuel pellet and chemical forms of iodine during the early phase of the accident because a release rate of semi-volatile FPs has various uncertainties. The present simulation set the detrimental factor of molybdenum used in FP release model as a sensitive parameter. The simulation results indicate that more molybdenum release causes more generation of hydrogen iodide and more deposition of iodine inside Reactor Pressure Vessel (RPV) because the adsorption velocity of hydrogen iodide is comparatively higher than deposition velocities of another FPs.

Multiple Time-Scale Molecular Simulations: Modeling Realistic Loading Rates

2007 ◽  
Author(s):  
S. N. Medyanik ◽  
E. Guleryuz
Keyword(s):  
Time Scales ◽  
Md Simulation ◽  
Multiple Time ◽  
Strain Rates ◽  
Simulation Methods ◽  
Multiple Time Scale ◽  
Loading Rates ◽  
Simulation Results ◽  
Experimental Values

The vast gap between the molecular dynamics (MD) and experimental time scales poses serious problems to direct comparison between the MD simulation and experimental results. The inability of the traditional MD simulation methods to model long enough time scales also results in modeling unrealistically high loading rates and strain rates that are usually at least six or seven orders of magnitude higher than the corresponding experimental values. This may have a tremendous effect on the realism and quality of the simulation results.

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