• ## R language Lasso regression model variable selection and diabetes development prediction model

Time：2021-8-22

Original link:http://tecdat.cn/?p=22721  Lease absolute shrinkage and selection operator (lasso) performs regularization and variable selection on a given model. Depending on the size of the penalty term, Lasso reduces the less relevant predictors to (possibly) zero. Therefore, it enables us to consider a more concise model. In this set of exercises, we will implement lasso regression […]

• ## Extension end data tecdat: R language Bass model for sales forecast

Time：2021-8-3

Original link:http://tecdat.cn/?p=3937 Original source:Tuo end data tribal official account Bass diffusion model Bass diffusion modelThree parameters: total number of people who finally purchased products m; Innovation coefficient P; And imitation coefficient Q, nls(Sales~M*(((P+Q)^2/P)\*exp(-(P+Q)\*T79))/(1+(Q/P)\*exp(-(P+Q)\*T79))^2, ## Parameters: ## Estimate Std. Error t value Pr(>|t|) ## M 6.80e+04 3.13e+03 21.74 1.1e-07 *** ## P 6.59e-03 1.43e-03 4.61 0.0025 ** ## Q 6.38e-01 4.14e-02 15.41 1.2e-06 *** ## — ## Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ‘ 1 ## ## Residual standard error: 727 on 7 degrees of freedom ## ## Number of iterations to convergence: 8 ## Achieved convergence tolerance: 7.32e-06 #   Gain coefficient Bcoef <- coef(Bass.nls) m <- Bcoef\[1\] p <- Bcoef\[2\] q <- Bcoef\[3\] Set the […]

• ## Android 11 balance process and principle

Time：2021-6-26

It is mentioned in a document of Qualcomm that Android 10 audio has introduced a balance function (for reasons of confidentiality, the specific document name should not be posted), and the content of the document is simple, so the setting interface and dumpsys view value are proposed, Let’s study how Android implements this thing and […]

• ## R language time-varying panel smooth transition regression model tv-pstr analysis of the impact of debt level on investment

Time：2021-6-4

Link to the original text:http://tecdat.cn/?p=21506 When two states are adopted, the single transfer function PSTR model has two variables The basis of our empirical approach includes assessing capital liquidity in n countries. The corresponding model is defined as follows: ​ Among them, it is the ratio of domestic investment to GDP observed in the ith […]

• ## Source code interpretation: cssrnn

Time：2021-4-29

Source code:Cssrnn GitHub link, ijcai2017 Model interpretation current embedding: [state_ size, emb_ Dim], where state_ Size is the number of links or grids, EMB_ Dim is the dimension of embedding. destination embedding: [state_ size, emb_ [dim], ditto; The terminal embedding is a separate set. Neighbor embedding: in fact, it is a set of coefficients of […]

• ## Digital potentiometer-x9c103piz

Time：2021-3-31

The digital potentiometer is mainly used to establish the voltage to voltage ratio circuit, which is not suitable for series connection of pure variable resistor and external resistor 1. It can carry small current, generally in 1mA ~ 3mA 2. Its internal resistance is connected through MOS tube, so it is greatly affected by voltage, […]

• ## [data structure] – polynomial multiplication

Time：2021-3-24

Title Requirements The non-zero coefficients and corresponding exponents of two polynomials are input from the character file to establish the polynomial representationLinked Storage Structure To calculate the product of the two polynomials and to output the product of the polynomialsAll nonzero coefficients and corresponding exponentsTo another character file. Algorithm principle The multiplication of two polynomials […]

• ## Using non convex penalty function regression (SCAD, MCP) to analyze prostate data in R language

Time：2021-3-12

Link to the original text:http://tecdat.cn/?p=20828  In this paper, Lasso or nonconvex penalty is used to fit the regularization of linear regression, GLM and Cox regression models_ Minimum_ Most_ Fovea magna_ Degree_ Punishment_ Function_ (MCP)_ And smooth slice absolute deviation penalty (SCAD), as well as other L2 penalty options (“elastic network”). Utilities for performing cross validation […]

• ## One variable polynomial addition calculator

Time：2021-2-4

include <stdio.h> include <stdlib.h> typedef struct Polynode { Int coef; // coefficient Int exp; // index struct Polynode* next; }Polynode,*Polylist; //Input data, input while sorting into the linked listvoid InputDataAndSortingData(Polylist Polynomial, int n); //Initialize polynomial linked listvoid Init(Polylist &Polynomial); //Add two polynomialsvoid PolynomialAdd(Polylist A, Polylist B); //Output calculation resultsvoid DisplayResult(Polylist A); //Command input and judgmentint […]

• ## Tensorflow course (first two) — polynomial regression

Time：2020-11-6

Series articles： Tensorflow tutorial (first one) — linear regression Tensorflow course (first two) — polynomial regression Tensorflow tutorial (first three) — Logical Regression Tensorflow course (1) — linear model Standard equation method There is not only gradient descent method to solve the cost function, but also the gradient descent method needs to select the appropriate […]

• ## Primary analog circuit: 8-4 controlled source circuit

Time：2020-10-26

Back to the catalog With the characteristic that the output of ideal operational amplifier can output any voltage and any current, we can use ideal operational amplifier to build a variety of controlled power supply. Of course, in practical use, the output of op amp should not exceed the maximum value given in its data […]

• ## Chapter 4 bjrobot linear speed correction

Time：2020-9-26

BJROBOT Linear velocity correction   1.The carLay flatOn the floor, use a tape measure as the measuring scale,Select the front or rear of the car as the starting point of the car, Open the virtual machine in the data and open a terminal ssh In the past, the main control terminal started roslaunch znjrobot bringup.launch。 2.Open […]