Numerical Analysis and Scientific Computing Commons^™

Modeling Analysis And Prediction On Ncp Epidemic Transmission, Huaxiong Sheng, Wu Lin, Changliang Xiao

Journal of System Simulation

Abstract: The modeling analysis on the NCP (Novel Coronavirus Pneumonia) epidemic transmission before and after the closure of Wuhan is presented. On the basis of preprocessing the epidemic data, the classical SIR model and differential recurrence method are used to analyze and forecast the epidemic situation in the stage of control. The theoretical value and measured value fits well. In the stage of free transmission, the logistic model is used to compare and analyze the epidemic data five days in advance or later with the actual data to show the importance of taking the epidemic prevention measures in time. The …

Research On Control Technology Of Aeroengine Heat Exchanger, Qingyang Jiang, Song Hua

Journal of System Simulation

Abstract: In order to solve the high temperature problem caused by the high speed of the synergistic aspirating engine, this paper designs a control algorithm for the heat exchanger. In the process of designing the control algorithm, considering the strong nonlinearity, uncertainty and strong coupling of the engine, The decoupling study of the multi-input and multi-output linear model of the heat exchanger is carried out. The decoupling effect of two different decoupling methods on the strongly coupled heat exchanger is obtained. The fuzzy decoupling PID controller has short adjustment time and overshoot. Small, conclusions with better decoupling effects.

Research On Cost-Effectiveness Analysis And Modeling Of Equipment, Yueqiang Zhao, An Shi, Mai Qiang, Yinyin Lin

Journal of System Simulation

Abstract: There are many methods to study the cost effectiveness analysis of equipment. It is very important to choose the right method and method combination . On this basis of analyzing and sorting out the research status at home and abroad, the collation and comparative study of cost estimation methods and modeling methods are carried out.The methods and classifications of effectiveness evaluation and calculating and aggregating efficiency indicators are sorted out. The methods suitable for cost-effectiveness analysis and decision-making are summarized. The characteristics of these methods in the analysis of equipment system and their applicability to engineering application are pointed …

Modeling And Simulation Of Missile Trajectory Based On Practical Sampling, Wu Shuai, Xiaohua Zhou, Lili Wang, Xingzhong Yao

Journal of System Simulation

Abstract: Aiming at the problem of lacking the proper simulation method for missile trajectory in combat simulation training, this paper analyzes the limitations of the 6D and 3D simulation models, proposes a method of trajectory simulation with missile kinematics model and history measured data, and taking an air-to-surface ballistic missile with midcourse-terminal guidance as an example, describes the model construction process in detail. Through the verification, validation and simulation experiments, it shows that this method can simulate various types of missile trajectory with high confidence on both sides of “red and blue”, which has an important reference meaning for missile …

Modeling And Timing Simulation Of Turbojet Engine Starting Process, Wang Lei, Liying Yang, Hongda Zhang, Yuqing He

Journal of System Simulation

Abstract: The turbojet engine is complicated in its starting process and requires collaboration and cooperation involving all the execution structures, thus higher demand is put forward for the control system. How to model the engine starting process, and then accurately describe and analyze the impact of actuator states on engine performance directly affect the engine control system performance. According to the working principle of the JetCat-P400 German turbojet starting process, the rotor speed mathematical model of the turbojet engine starting process is constructed by the component method. The parameters of the model are identified by combining the experimental data of …

Evaluation And Modeling Of Visual Fatigue In 3d Display Based On Ecg, Danli Wang, Xinpan Yang, Yue Kang, Haichen Hu

Journal of System Simulation

Abstract: This study investigates and models the correlation between visual fatigue and ECG data by collecting the ECG data of the participants during watching 3D movies, combining with the subjective scores, the reaction time, and the questionnaires before and after the experiment. ECG data of 12 subjects were analyzed in both time and frequency domain. The results showed that subjective score and HR increased with the duration of viewing, while PNN50 decreased. Linear model of subjective score is established, and the R² of model is 0.930. Subjective questionnaires show significant changes in overall visual fatigue, dry eyes and nausea symptoms …

Historical Data Modeling Based On State Observation, Dong Ze, Erxin Yin

Journal of System Simulation

Abstract: Aiming at the problem that the conventional historical data modeling method can not overcome the influence of disturbance on modeling accuracy, a historical data modeling method based on state observation is proposed. In this method, the data with the characteristic from dynamic to steady state are selected from the historical data as the modeling data, which is subjected to zero initialization processing based on the final steady state value. The processed data is then divided into two segments. The first segment is used to track the state of the prediction model, and the final observed state is used as …

Channel Modeling And Simulation Of Wireless Underground Sensor Networks Based On Magnetic Induction Technology, Zhouzhou Liu, Shen Liang

Journal of System Simulation

Abstract: Aiming at the problem of high path loss, huge dynamic changes of channel conditions and large antenna size of the electromagnetic wave communication channel in wireless underground sensor networks ( WUSN), the channel characteristics of magnetic induction (MI) in the process of WUSN transmission are studied and the transmission principle of harmonic source in soil strata is analyzed. The influence of the polarization direction of the coil and the eddy current loss coefficient on the channel model is analyzed by the transmission equivalent circuit diagram, and the influence of the change of the frequency and the distance on the …

Modeling And Simulation Of The Crosstalk On Aircraft Arinc429 Data Bus, Xudong Shi, Ruowen Wang, Jialin Wang, Hongxu Zhao

Journal of System Simulation

Abstract: Based on the theory of multi-conductor transmission line, the crosstalk between a single cable and a UTP (unshielded twisted pairs) cable was studied. The MATLAB and CST were employed to do the theoretical calculation and modeling respectively, and the comparison result proved the validity and accuracy of the proposed model. Based on the UTP model, the shielding layer was used to build the STP（shielded twisted-wire pairs） model according to the ARINC429 specification, and the crosstalk which caused by a large voltage transient happening on the adjacent power line on the aircraft was further analyzed. The distance and length of …

Teaching Stats For Data Science, Daniel Kaplan

Faculty Publications

“Data science” is a useful catchword for methods and concepts original to the field of statistics, but typically being applied to large, multivariate, observational records. Such datasets call for techniques not often part of an introduction to statistics: modeling, consideration of covariates, sophisticated visualization, and causal reasoning. This article re-imagines introductory statistics as an introduction to data science and proposes a sequence of 10 blocks that together compose a suitable course for extracting information from contemporary data. Recent extensions to the mosaic packages for R together with tools from the “tidyverse” provide a concise and readable notation for wrangling, visualization, …

Modeling Topics And Behavior Of Microbloggers: An Integrated Approach, Tuan Anh Hoang, Ee-Peng Lim

Research Collection School Of Computing and Information Systems

Microblogging encompasses both user-generated content and behavior. When modeling microblogging data, one has to consider personal and background topics, as well as how these topics generate the observed content and behavior. In this article, we propose the Generalized Behavior-Topic (GBT) model for simultaneously modeling background topics and users' topical interest in microblogging data. GBT considers multiple topical communities (or realms) with different background topical interests while learning the personal topics of each user and the user's dependence on realms to generate both content and behavior. This differentiates GBT from other previous works that consider either one realm only or content …

Hydraulic Conductivity As A Proxy For Drainage System Connectivity In A Subglacial Hydrology Model, Jacob Z. Downs

Graduate Student Theses, Dissertations, & Professional Papers

The link between subglacial hydrology and basal sliding has prompted work on basal hydrology models with water pressure and storage as prognostic variables. We find that a commonly used model of distributed drainage through linked cavities underpredicts winter water pressure when compared to borehole observations from Issunguata Sermia in Western Central Greenland. Possible causes for this discrepancy including unrealistic model inputs or unconstrained parameters are investigated through a series of modeling experiments on both synthetic and realistic ice sheet geometries. We find that conductivity acts as a proxy for the connectivity of the linked cavity system and should therefore change …

Prediction Of Laser Ablation In Brain: Sensitivity, Calibration, And Validation, Samuel J. Fahrenholtz

Dissertations and Theses (Open Access)

The surgical planning of MR-guided laser induced thermal therapy (MRgLITT) stands to benefit from predictive computational modeling. The dearth of physical model parameter data leads to modeling uncertainty. This work implements a well-accepted framework with three key steps for model-building: model-parameter sensitivity analysis, model calibration, and model validation.

The sensitivity study is via generalized polynomial chaos (gPC) paired with a transient finite element (FEM) model. Uniform probability distribution functions (PDFs) capture the plausible range of values suggested by the literature for five model parameters. The five PDFs are input separately into the FEM model to gain a probabilistic sensitivity response …

Oyster Sustainability Modeling As A Public Resource, Nathan A. Cooper

LSU New Orleans Theses and Dissertations

A simulation algorithm based on biological references points proposed by Powell and Klink (2007) is implemented for predicting the total allowable catch of eastern oysters (Crassostrea virginica) from Louisiana’s coast. The model accepts initial per-square-meter shell mass and oyster size distributions as input. Fishing effort is provided as fractions removed of each resource for each month of the season. The model outputs the expected remaining shell mass and harvests of sack and seed oysters after discrete fishing months. Oyster mortality credits the shell budget, while fishing fractions debit oyster and shell resources. Surviving oysters grow larger along a …

A Model For Anticipatory Event Detection, Qi He, Kuiyu Chang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Event detection is a very important area of research that discovers new events reported in a stream of text documents. Previous research in event detection has largely focused on finding the first story and tracking the events of a specific topic. A topic is simply a set of related events defined by user supplied keywords with no associated semantics and little domain knowledge. We therefore introduce the Anticipatory Event Detection (AED) problem: given some user preferred event transition in a topic, detect the occurence of the transition for the stream of news covering the topic. We confine the events to …

Bias And Controversy: Beyond The Statistical Deviation, Hady W. Lauw, Ee Peng Lim, Ke Wang

Research Collection School Of Computing and Information Systems

In this paper, we investigate how deviation in evaluation activities may reveal bias on the part of reviewers and controversy on the part of evaluated objects. We focus on a 'data-centric approach' where the evaluation data is assumed to represent the ground truth'. The standard statistical approaches take evaluation and deviation at face value. We argue that attention should be paid to the subjectivity of evaluation, judging the evaluation score not just on 'what is being said' (deviation), but also on 'who says it' (reviewer) as well as on 'whom it is said about' (object). Furthermore, we observe that bias …