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Questions tagged [operations-research]

uses mathematical and statistical methods to improve efficiency

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Robust or Stochastic Optimization Approach for Maximizing Profit with Limited Price Information

I am tackling a linear maximization problem where I need to select the optimal product among several options over a series of weeks, given certain constraints, in order to maximize future profit. The ...
anasse's user avatar
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1 vote
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Stochastic Task Processing Times in Queueing Theory

I'm struggling with an operations research problem which has 3 stations containing 3 different task processing times and different coefficients of variation (for example, station 1 has 3 tasks with ...
user405518's user avatar
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What is the approximate distribution of the distance between gas stations along a highway?

Thinking it should be exponential, but I could be wrong.
Mazen Danaf's user avatar
1 vote
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35 views

Case study question on profit optimization

A famous restaurant selling burgers has closely studied the demand for burgers for past months including the times the customer requested a burger and it was already sold out. Further analysis of data ...
the_why_guy's user avatar
1 vote
0 answers
18 views

Estimating Joint Probability from limited data

This is probably a broad question but I am interested in getting the Joint PDF for n random variables each of which can take integer values within a finite range. I have data in the form of time ...
arvind rathore's user avatar
1 vote
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102 views

Python implementation of standard Expectation maximization algorithm to estimate position bias in LTR

Is there any Python implementation that would allow to use logs data of clicks and their ranking, and return and estimate of relative position bias as discussed in section ...
Tony's user avatar
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1 answer
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Criteria evaluation for cluster generation in R

The code below finds the "optimal" number of clusters. In the example below, the result was 2 clusters. Quickly explaining the code: first, the Ideal Point is calculated, which has the ...
JVieira's user avatar
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2 votes
0 answers
97 views

Can I use xboost as objective function in an optimization problem?

I am working on a marketing optimization problem, where the goal is maximize profit by optimally allocating spend to different products. Constraint is getting at least 1 Million revenue. As a first ...
tjt's user avatar
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1 vote
2 answers
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What methods exist to identify the optimal splits in some exogenous variable, such that a dependent variable is maximized?

I've come across an interesting problem recently, and I'm wondering if I'm missing some obvious approach here. The problem statement is thus: Imagine I run an online business, and I'm interested in ...
Guy Incognito's user avatar
9 votes
2 answers
527 views

What are differences between industrial statistics and social science statistics/econometrics that are potential stumbling blocks?

Main question up front: what are differences between econometrics/social science statistics that and industrial statistics that people switching between the two should be are of? I got a PhD in ...
cgmil's user avatar
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Statistical approach for football competition

There are 10 teams in a club. Each week, there are 3 games where each team plays another team from the same club. All games are played in the same park. The park has 5 pitches. There are 5 teams that ...
Pedwor's user avatar
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Where can I learn the math behind how airlines dynamically price tickets?

It's easy to think of factors that airlines take into account, and how the price will vary over time. There are no shortage of articles or medium posts about that. But how can I frame this as a ...
goopy's user avatar
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Visualising Gantt chart distribution

I perform $n$ simulations of operations planning. I can plot a gantt chart for each simulation, but I am interested in visualising the variability of the whole simulation set : I want a Gantt ...
Clément F's user avatar
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3 votes
2 answers
961 views

Bayesian genetic algorithms?

I'm not sure that "Bayesian genetic algorithms" is a real term or even a concept in research. For a while now, I've preferred genetic algorithms as my go-to heuristic optimization technique, ...
jbuddy_13's user avatar
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3 votes
1 answer
362 views

How to derive a conclusion with the scatterplot that we made using the data in a quantitative research? [closed]

How can we write the result section by using the scatter plot that we made using the data in a quantitative research. Also most importantly if the scatter plot shows no correlation.
Kasuni Maheeshi Abeykoon's user avatar
2 votes
1 answer
65 views

Survival analysis with unobserved right censoring

Assume we have a tire shop and would like to build a survival curve for the lifetime of our tires.Once we know how long our tires are useful, we can send push notifications prompting customers to get ...
Data Dan's user avatar
5 votes
1 answer
2k views

QR Factorization to Solve Least Squares Without Using an Inverse

I'm playing around with different ways to solve least squares, and am using numpy to derive values for $\beta$ in a regression problem. I know that if you do a $QR$ factorization of $X$ such that $...
Jonathan Bechtel's user avatar
2 votes
1 answer
1k views

Simulating a queue in R [closed]

It's noted that the number of folks in a stationary system will maintain an average equal to the rate of arrival multiplied by the mean of the service distribution. Where the formula $L = \lambda$ ...
user253521's user avatar
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Formulating a mixed integer programming problem with a binary maximization term

Real-world description of the problem: In the US, funding for school lunch programs is given to local school districts by the Federal government. If >=40% of students in a school or group of schools ...
Adam Rivers's user avatar
1 vote
0 answers
140 views

Student-Teacher matching problem

The problem I want to solve is as follows: I have data about how many teaching hours different students spend with their teacher in order to pass their exams. The teaching varies from 25-55 hours. In ...
Chris Ng's user avatar
2 votes
0 answers
72 views

How to handle real-world (soft) constraints in an optimization problem? [closed]

I am working on a problem which involves optimizing for minimum power consumption in a large compressor network interconnected through pipelines (think of a connected graph with nodes as compressors ...
chupa_kabra's user avatar
0 votes
1 answer
89 views

qualitative data in data envelopment analysis (DEA)

I wish to use qualitative input to calculate efficiency using DEA model. For that I based the input on certain questions which were answered on 1-5 rating scale. each input has 5 such questions(...
ritika's user avatar
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1 vote
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Which optimization algorithm applies better for this production problem? Cost minimization

This is a cost minimization problem, where I have to plan the development of a field and the installation of some machines there. Rectangles A,B,C,D represent production areas, that can overlap. I ...
Luis's user avatar
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1 answer
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How many people at any given time

I have been tasked with finding out approximately how many people were in a location at a given time. I know how many people arrived per hour and how many people left per hour and the average time ...
MCP_infiltrator's user avatar
0 votes
1 answer
195 views

Assignment Problem (Linear Programming, Genetic Algorithm, etc.)

I'm looking for advice on how I should approach a specific problem. Some background first: The problem is about shipments falling into a bin. There are 19 such bins, which are further sorted into 20 ...
Siddharth Mehta's user avatar
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1 answer
416 views

Monte Carlo simulation--Have I applied Bernoulli distribution properly? [closed]

I am trying to run a monte carlo simulation and I just wanted to make sure that I set it up properly. A salesman visits 100 different homes. Someone answers the door 80% of the time. Of that ...
A. Mar's user avatar
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-1 votes
1 answer
62 views

Sample size human sciences [closed]

I will apply a questionnaire with 90 questions about the possible requests: very bad, bad, neutral, good and very good, the answers will be categorized into 8 different groups. Subsequently the data ...
Joyce M.'s user avatar
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1 vote
1 answer
169 views

Office Desk Rota Assignment problem

This is not a home work and the question is not related to studies (I am not a student). I have to do the weekly desk rota at the office and thought this forum might help with suggestions. My problem ...
PSP's user avatar
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2 votes
1 answer
166 views

Is this a contextual bandit problem?

I have an operations research problem that I would like to solve but I am unsure what the correct framework for analyzing it would be. The closest I've come across so far is contextual bandits I ...
guy's user avatar
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1 vote
0 answers
35 views

How can we decompose generalization gap as done in the paper "Generalization in Deep Learning"?

I am reading a recent paper "Generalization in Deep Learning" and I am unable to understand a step. In this step, they first take neural network as a direct acyclic graph(DAG) and described output of ...
Muhammad Awais's user avatar
1 vote
0 answers
199 views

How to deal with NaN when they make up 45% of the data?

I compare two countries (Germany and Sweden) and have 30 variables over 15 (2001-2016) years. Unfortunately, the first years (2001-2007) for Sewden and (2001-2006) for Germany have NaN (missing values)...
user21's user avatar
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1 vote
1 answer
202 views

Design of experiment: Is there correlation between performance vs. employee attrition?

Background: Assume company X has a cyber security incident team. One of their key performance/risk indicators is how fast they triage the security incidents. For the past 2 quarters, COO observed ...
Johnny 's user avatar
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stochastic inventory question

Does anyone have any references for inventory optimization? By optimizing I mean going from supplier to the allocation to the store. I am doing research as to how to optimize any given inventory ...
9 votes
1 answer
3k views

What is the difference between the Poisson distribution and the uniform distribution?

I'm modeling a factory with orders arriving independently of each other. I need a series of actual time stamps of arrivals. I've been told that everyone uses the Poisson distribution to model arrivals....
All The Rage's user avatar
1 vote
0 answers
22 views

Does anyone here knows this variable? No one had ever answer this yet in all sites I've been. [duplicate]

what does "W" represents there in the equation 2? no one had ever answer this yet in all sites I've been. here is the source. http://www.scirp.org/journal/PaperInformation.aspx?PaperID=65933
user avatar
3 votes
1 answer
2k views

What concepts in optimization do I need for machine learning?

I am a Math/CS dual major. As part of my math major, I have the option of taking optimization and mathematical programming classes. I am also interested in machine learning. I know that a lot of ...
Halbort's user avatar
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0 answers
127 views

Discrete optimisation of a gym workout routine

I am working on the following problem, which I would like to solve using an elegant optimisation method (both because the answer is genuinely useful to me, and because I am interested in the maths of ...
Karnivaurus's user avatar
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2 votes
1 answer
29k views

If the mean is equal to the standard deviation, what is the general likelihood that the underlying distribution is normal vs exponential?

This comes from operations analysis. Often you have measurement of times, such as time between customers arriving at a store (e.g. Starbucks) or time it takes to process an order (e.g. a cappuccino). ...
Michael Herman's user avatar
5 votes
2 answers
4k views

Why do Statistics, Machine learning and Operations research stand out as separate entities

It seems nowadays people who work in ${\bf Statistics, \ Machine\ Learning \ and \ Operations\ research }$ all consider themselves as working in data analytics. These three categories try to ...
Wis's user avatar
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1 vote
0 answers
172 views

How to optimize call center call times?

I have been asked to develop a predictive model to optimize call times from a call center. We have historical data on successful calls, date/time, member-specific attributes, etc. Ideally, the output ...
chad39's user avatar
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1 vote
0 answers
33 views

Comparing coefficients to understand the change in impact of a variable

Our success measure (satisfaction) have dropped in July compared to June. I want to understand the factors that affected the drop. Since I could not create a flag that identify records that ...
Tarek Soukieh's user avatar
2 votes
0 answers
187 views

effect of linear term on quadratic programming

What's the impact of linear term ($d$) on quadratic programming problem ($P$) described as follows \begin{align*} \min_x d^T x + 1/2 x^T D x\\ \text{such that }A^T x \geq x_0 \end{align*} where $D$ ...
alya's user avatar
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0 votes
1 answer
33 views

What type of test / research design is recommended for this analysis

It is assumed that people are not seeking for help when they need to, therefore a program is implemented to teach them when to seek help. People can join the program voluntarily. I would like to study ...
jackfood's user avatar
0 votes
1 answer
1k views

Reverse Code for Factor Analysis

I have done my survey, and now I need to do the data analysis. However, I am not sure whether or not I need to do the reverse code at the first step before I can do the remaining analysis. There are ...
thavi's user avatar
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1 vote
0 answers
90 views

Modeling worker performance parameters for optimum allocation of tasks to workers

Lets say we have an English to French translation task in a company and there are 100s of workers who are proficient in doing this task but each worker has its own unique attributes which allow them ...
stats101's user avatar
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2 votes
1 answer
89 views

Sample size for clinical research

I determined the sample size already (25), but I want to know if it has to be increased because of a minor change. Our study consists of two groups - one will be sedated and the other will not. For ...
Anitha's user avatar
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1 vote
0 answers
318 views

online bin packing and machine learning

I am trying to optimize scheduling disk allocation in data centers. In nature it is an online bin packing problem. But, since each customer has it's own behavior or kind of workload I was wondering, ...
Babak Ravandi's user avatar
3 votes
0 answers
137 views

A YouTube View Estimator [closed]

Here's a thought experiment that I can't come up with a good answer for. Imagine you have 5 YouTube videos that you want to reach 50,000 views (10,000 views per video) by the 10th day after ...
MetroidPrime77's user avatar
4 votes
1 answer
4k views

Constrained assignment problem (Linear Programming, Genetic Algorithm, etc...)

I'm looking for advice on how I should approach a specific problem. I have about 1000 shops that I have to assign to about 20 different supply centers out of a possible 28, and I'm trying to pick the ...
gtnbz2nyt's user avatar
  • 225
4 votes
2 answers
2k views

What is a good model for revenue managment / price optimization problem

I am trying to create a dynamic pricing model to optimize revenue for a hypothetical business. Lets say I have an application that connects dog walkers to people who want to pay for their dog to get ...
Sean's user avatar
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