# Questions tagged [modelling]

Questions on how to represent real-world or non computer science problems with computer science tools.

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### Encoding "all-except" constraints in CNF

I am looking for an efficient CNF encoding of the following situation: I have sets of boolean literals $A = \{ a_1, \ldots, a_m \}$, $B = \{ b_1,\ldots, b_n \}$ and subsets $B_1, \ldots, B_m$, where ...
31 views

### System Identification vs Machine Learning for dynamic system modelling

So I found another discussion regarding this, but the answers did not fully separate the differenced between SID and ML. Hopefully a discussion here can shed some light on some larger differences both ...
73 views

### Least squares fit of a rational function

I am fitting different 2D geometric transformations by least-squares. For instance quadratic, $$\begin{cases}a'x^2+b'xy+c'y^2+d'x+e'y+f'=X\\a''x^2+b''xy+c''y^2+d''x+e''y+f''=Y\end{cases}$$ which is ...
1 vote
28 views

### A lower bound for the makespan of heterogenous fog nodes

Why there is a sigma in the denominator of equation (8) in the picture? suppose we have n tasks and m fog nodes.
24 views

### What is the best way to predict a continuous score based on image characteristics(pixels)?

I have a dataset with 9912 images, what is the best way to train them based on the pixels and features of the images to be able to predict a continuous target ranging from 1 to 100? The goal is to ...
1 vote
72 views

### How to model an inverse "token relationship" in Petri nets?

Suppose I have the following Petri net: I wonder whether it is possible to model an inverse relationship between $p2$ and $p3$. Basically what I want to achieve is to make either $t1$ or $t2$ ...
1 vote
14 views

### Best way to deal with strongly correlated variables in a prediction problem?

I am doing a prediction assignment as part of a machine learning course using loans data. I have just done some exploratory data analysis on my dataset of just over 9000 rows. There are 11 variables ...
19 views

### implementing a 802.15.4 math model based on a paper. How to verify it

I am implementing a mathematic model for predicting the congestion of 802.15.4 network based on the paper: Performance analysis of IEEE 802.15.4 non-beacon mode with the unslotted CSMA/CA Based on the ...
33 views

### Search algorithm for multidimensional space with custom topology

First, let's start with the description of the problem in dimension 1: Let $T_0$ be a space with $n$ nodes organized in a tree structure, with $m$ of those nodes defined as target nodes. In this space,...
1 vote
56 views

### Explanation of roofline model

I am currently studying the roofline model. Wikipedia  shows the following example graph: The diagonal line shows $\beta * I$. But I do not understand why this line does not go through the zero ...
32 views

### How to specify mutated types mathematically?

Say I have an object which I pass to a method, and the method returns that same object, just mutated. So it goes like this: ...
166 views

### How do you have a type typed "Type" when implementing a programming language?

I am working on the base of a language model, and am wondering how to represent the base type, which is a type Type. I have heard of an "infinite chain of ...
61 views

56 views

### How to simulate systems' unavailability?

I am simulating a system where the clients' unavailability is one big issue to the systems behavior. I gathered the real system logs to analyze the unavailability of the clients in the deployment ...
140 views

### CNF form of variable assignment problem

There are n variables $x_1$, $x_2$,..., $x_n$ and each one of them takes values from 1 to k (k>= n) and all are distinct. How can I represent this in the CNF form? (I tried the trivial way of trying ...
58 views

### An alternative to the object paradigm

I've been playing around with an alternative to the standard object-oriented paradigm for modeling data, and I would like to know if there is any research or already existing systems along the same ...
1 vote
398 views

### Scheduling N variable-time interdependent tasks across M workers

I have N tasks, each of them requires some time to complete. Time to complete is not the same for all tasks. Each task may depend on a number of other tasks (assume, that no dependency cycles are ...
1k views

### Stereotype in UML

What is a Stereotype in Unified modelling language?And What are the primary class stereotypes?.I need clear explanation using diagrams or real world scenario.
47 views

### choosing right neural network architecture and input features

As a short example suppose we have a kind of pollution sensor and a jet fan in a tunnel. Jet fan turn on/off according to the automatic scenario based on pollution sensor value. Pollution itself ...
Suppose we have a multi-class classification problem, where the number of classes $K \geq 3$ We use a tree structure of multiple SVMs to divide and conquer the problem, with one example in the figure ...