Questions tagged [modelling]
Questions on how to represent real-world or non computer science problems with computer science tools.
97
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Trying to model HIV using cellular automaton but can't replicate the results of some paper
There is this paper in which HIV is modelled using cellular automaton. I am trying to replicate this work but I am not getting the same results as the authors. In this paper the authors describe the ...
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21
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Is the pinhole camera model appropriate for modelling a real camera?
I am developing a computer vision system, using the pinhole camera model. Is this an appropriate model to use for a real camera? I know that lenses and such will distort the image, my main questions ...
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34
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How to capture the update-delay of observable variable in a model?
I have a problem that I am trying to model, but I am unable to capture one particularity of the system that seems to be crucial. I will try to give an abstract description first and then the toy model ...
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144
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Real-life applications of pure Mealy machines
I'm currently studying formal methods in software engineering related to state machines, specifically Mealy machines. This made me wonder how relevant Mealy machines really are for practical ...
- 161
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50
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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 ...
- 166
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57
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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 ...
- 121
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78
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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 ...
user16034
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32
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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.
- 25
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26
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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 ...
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1
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94
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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 $t2$ ...
- 113
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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 ...
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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 ...
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36
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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,...
- 101
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71
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Explanation of roofline model
I am currently studying the roofline model. Wikipedia [2] 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 ...
- 15
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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:
...
- 2,163
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3
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166
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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 ...
- 2,163
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A voting scheme where votes are scriptable
I am looking for literature on mathematical models of (political) voting schemes. Concretely, I am interested in models that allow votes of the following form:
"I am voting for $X$, but only if $...
- 438
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65
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Are objects appropriate for modeling the real world?
First of all, I know objects are not meant to model the real world, although they have been marketed as such and perhaps that was an intention at some point.
Here I say 'modeling the real world' in a ...
- 113
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1
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55
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Tools for modelling compilers
I'm a wannabe mathematician, whose master's thesis is (by the looks of it) going to focus on a certain "compiler", used to produce learning materials from a subset of $\LaTeX$, in the context of ...
- 141
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Is there a way to connect a deep language model output to input?
In models like GPT-2, TXL and Grover, is there a good way to know which input weights (tokens) resulted in each token of the output?
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49
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How to model references in an ontology
I am interested in creating an ontology which will model arguments (among other things). For example, a triple in the ontology might be
...
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2
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2k
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What is the difference between "information model" and "conceptual model"?
I am trying to figure out the difference between information and conceptual models. For me, both terms seem to mean be the same, but I cannot find a reference where this is established. They are never ...
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496
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How to write an if then logical constraint given part of the input related to a decision variable?
I am trying to solve an assignment problem-like from a bi-objective persepctive where I have a marketplace of vendors proposing different machines with different types and specs. The goal is to select ...
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How to evaluate the learned prototypes for multivariate time-series (e.g. motion)?
Consider a method which finds prototypes for multivariate time-series (MTS) data, and is designed to find prototypes for each class of data.
For example, the {walking} class consists of some slightly ...
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Restriction for greater than constraint in linear programming
I have a model that considers real values and that uses a binary variable $x$. In this model, the following conditions should apply:
\begin{equation}
x=
\begin{cases}
0, & \text{if}\...
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1
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57
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What is a logical approach to developing an algorithm which can find the optimal parameters for a function which make it best fit a given data set?
Consider the highlighted columns in the following table:
Starting with 100,000 newborns, $l_{x+2}$ denotes the number of individuals in the sample still alive at age $x+2$. If we consider Makeham's ...
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126
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How to model an ''affinity constraint'' in assignment problem
Working on an optimization problem formulated using the well known assignment problem. My decision variable is defined as follows :
$$\alpha _{x}^{r,u} = 1\begin{cases}
& \text{ 1 if } \mathbf{...
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28
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How to define a generic evaluation metric
Given a system (S) that accepts a tuple of parameters ($\alpha, \beta, \gamma \dots$ etc). These parameters affect the performance of S in a different way. For instance, decreasing $\alpha$ would ...
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1
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70
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Develop a winning strategy for a game
Okay so I've been going crazy about this problem I was given. It is as follows:
Given a pile of N matches, 2 people take turns removing matches from the pile. When it is your turn you are allowed ...
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203
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Is this problem just an application of traveling salesman? If not is it some other already "solved" problem?
Description of the problem in question:
Say I have a complete graph with positive weighted edges. 1 vertex is specified as the "end". A subset of the other vertices are designated as "start" vertices....
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DAGs and Equivalence Class of DAGs
I am learning DAGs and Equivalence Class of DAGs, I am reading the material by Prof. Campos Ibáñez here: https://www.cs.cmu.edu/afs/cs/project/jair/pub/volume18/acid03a-html/node2.html
However, I ...
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B2B integration modelling tools and standard suggestions
This question might be too broad, but I really need help with this. I am required to choose a standard or notation to model an integration between two business processes, one of which is external.
...
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97
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How to convert two conflicting objective functions into a single objective function
I have two objective functions say f1 where I have to minimize (X+Y) and another function f2 where I have to maximize (A-B). The two functions are conflicting.
I need to convert them into a ...
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268
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How can union-find algorithm be used with "real" data
In the beginning of the Princeton algorithms course the Dynamic connectivity problem is presented (quick-find, quick-union). Here is how it's described:
The input is a sequence of pairs of integers,...
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387
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Modeling tiling problems as SAT problems
I read that tiling problems can be modeled as satisfiability problems (2-SAT?), but the author did not explain how. Is this true? What would be an example?
By a "tiling problem" I mean you have a ...
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80
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Applying Ford-Fulkerson to settle a business lunch
I want to organize a business lunch with two societies $E_1$ (mine) and $E_2$. Each society is made of four people from the Executive management and 6 of the Financial Management. I want to organize ...
2
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3
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242
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Integer linear programming formulation of formula in DNF
I have multiple sets, e.g.,
$$\{1, 2\}, \{2, 3, 4\}, \{1, 4\}$$
Each variable $1, 2, 3, 4$ is binary. I need to represent the following condition without additional variables
$$(1 \land 2) \lor (2 \...
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2
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306
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Matching two people. One has 7% in common with the other. The other has 70% in common. What's a fair match score?
I am exploring some ideas around dating site matching, and I can do with some ideas as to which is the better solution
Senario: We have a boy and girl, the boy has completed his profile/bio ...
2
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1
answer
318
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Expressing a logical constraint in integer programming
Let $x$ be an integer such that $x \in [ - 10,10]$ and $b$ a binary variable. Apply integer programming to express $b = 1 \leftrightarrow x \ge3$
My work:
\begin{equation}
\begin{cases}
\...
- 142
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1
answer
447
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Set Cover and additional constraints
Consider the following bipartite graph:
Each node in red color represents a warehouse $w = \{ 1,2,3\} $. For this example we have three warehouses located at different locations. Each warehouse has a ...
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3
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411
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How to Determine Places, Transitions and Tokens in a Scenario when Modeling with Petri Nets?
When modeling a scenario with Petri nets how should I determine the places, transitions and tokens?
Example:
There are two exam assistants in an exam hall observing the exam. They stand in front of ...
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Linear programming formulation for the single-source shortest path problem
In this course lecture; section 5.1, single-source shortest path (SSSP) is formulated as the following linear program (LP):
\begin{align}
\max &\sum d_u \\
\text{subject to} & \\
d_v &\le ...
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288
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The meaning of ontology in computer science
I am reading a paper and ran into this word Ontology-based, What does it really mean? I did searching about it but still ambiguous to me, can someone elaborate this ...
- 121
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51
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How to conceptually represent attributes (characteristics) of an object in logics?
I am reading about/working on the knowledge representation using OpenCog framework http://wiki.opencog.org/w/OpenCog_Framework which essentially is special kind of probabilistic logic (s.c. PLN - ...
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171
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Ambiguity in choosing the best ER model
I am actually little bit confused when I am reading through the text - Database system concepts by Henry F. Korth and others
I won't be able to understand one thing, which one of the following models ...
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46
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Modelling belonging of a real variable to an interval by a boolean variable
In the context of a MILP, I have variables $x_{t} \in \mathbb{R}$ which have a lower bound $x^{min}$ and an upper bound $x^{max}$.
Let $I_{1} = [x^{min},a_{1}], I_{2} = ]a_{1}, a_{2}], ..., I_{n} = ]...
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1
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57
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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 ...
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145
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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 ...
- 85
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60
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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 ...
- 153
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415
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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 ...
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