Questions tagged [modelling]
Questions on how to represent real-world or non computer science problems with computer science tools.
93
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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 ...
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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 ...
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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 ...
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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.
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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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72
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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 $t2$ ...
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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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33
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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,...
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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 ...
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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:
...
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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 ...
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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 $...
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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 ...
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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 ...
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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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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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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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492
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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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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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122
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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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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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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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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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93
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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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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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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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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 ...
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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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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 ...
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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}
\...
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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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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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287
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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 ...
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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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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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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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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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140
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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 ...
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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 ...
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398
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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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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.
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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 ...
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Modelling a dependency of multiple transitions on data in one place
We are modeling our process using a colored Petri net. One of the limitations we have is that when multiple transitions depend on one place, only one of those transitions will fire because then the ...
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How to mitigate the hierarchical error propagation in tree-structured classification
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 ...
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