Industrial and Systems Engineer | LinkedIn: linkedin.com/in/roberto-salazar-reyna/

Simulation Modeling

Steps to make the best out of your simulation study

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Simulation Modeling

Simulation is one of the most widely used operations research and management science techniques. It consists in the use of mathematical methods and computer techniques to imitate or simulate the operations of various kinds of real-world facilities and process, referred as systems. The assumptions of how a system works usually take the form of mathematical or logical relationships; they constitute a model that is used to try to gain understanding on how the corresponding system behaves.

Since most real-world systems are too complex to allow realistic models to be evaluated analytically, these models must be studied by means of simulation. In a simulation study, computers programs are used to evaluate a model numerically, and data are gathered in order to estimate the desired true characteristics of the model. …


R for Engineers and Managers

Creating Data Trees using R packages

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Data Trees

Data tress are visual representations of hierarchical data. They are widely used in multiple fields such as decision theory, machine learning, finance, organizational management, routing algorithms, computer science and programming. Data trees help organizing data into groups and subgroups based on a hierarchy.

Data Trees Elements

  • Root node: represents the very top node of the tree. All the existing data points, groups and subgroups end up linked to it. It is the node with the highest hierarchy.
  • Leaves: represent children of nodes with higher hierarchies (i.e. parent nodes). They can also be parent nodes of multiple branches of leaves with lower hierarchies.
  • Attributes: specific information associated to each leave or group of the tree. …


R FOR Industrial Engineers

Creating Simple Diagrams using R packages

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IPO Diagram

An IPO (Input-Process-Output) Diagram is a very high-level diagram used for systems analysis that visually describes business processes with the description of each component in word. It shows a process key inputs and resulting outputs after a set of operations. IPO diagrams are also widely used in software engineering applications.

Components

Inputs

Represent everything that enters the system to be processed or transformed to achieve the desired outcome. Inputs can be raw materials, information, data or even an outputs from another process.

Process

Represent the set of operations, calculations and steps required to transform the given inputs into the desired outcome. …


Programming Basics

Learning GitHub Essentials

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What is GitHub?

GitHub is a code hosting platform for version control and collaboration. It lets you and others work together on projects from anywhere. GitHub provides access control and several collaboration features such as bug tracking, feature requests, task management, continuous integration and wikis for personal, enterprise and open source project.

Creating a GitHub Profile

Don’t have a GitHub account yet? No problem. Create one here by clicking on the ‘Sign up’ button located in the right top corner. You will be asked to define a username, email address, new password and to verify your account.

Creating a New Repository

Whenever your are interested in starting a brand new project, you will want to store your codes and relevant files within a new repository. …


R for Probability and Statistics

Understanding Sampling Methods

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What is Sampling?

Sampling is the process of selecting a random number of units from a known population. It allows obtaining information and drawing conclusions about a population based on the statistics of such units (i.e. the sample), without the need of having to study the entire population.

Why is Sampling Used?

Sampling is performed for multiple reasons, including:

  • Cases where it is impossible to study the entire population due to its size
  • Cases where the sampling process involves samples destructive testing
  • Cases where there are time and costs constrains

Sampling Techniques

There are two types of sampling techniques:

  • Probability sampling: cases when every unit from a given population has the same probability of being selected. This technique includes simple random sampling, systematic sampling, cluster sampling and stratified random sampling. …


Python for Financial Analysis

Understanding Stocks Volatilities

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Stock Market and Investments

There is one main fundamental principle to make a profit out of investments in the stock market: sell stocks at a higher price than what you paid for. In other words: buy low, sell high. As simple as it sounds, but not as simple as it is.

However, there is always a time lapse between the stock price at its acquisition and its price at its selling; either its price increases or drops. For some stocks, the time required to increase (or decrease) their price is shorter or longer than for others. …


R for Industrial Engineers

Operations Research Miscellaneous Applications

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Operations Research

Operations Research is a scientific approach for decision making that seeks for the best design and operation of a system, usually under conditions requiring the allocation of scarce or limited resources. The scientific approach for decision making requires the use of one or more mathematical optimization models (i.e. representations of the actual situation) to make the optimum decision.

Diet Problem

The diet problem is one of the first and most common studied optimization problems. …


R for Industrial Engineers

Exploring the “lpSolve” R package

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Operations Research

Operations Research is a scientific approach for decision making that seeks for the best design and operation of a system, usually under conditions requiring the allocation of scarce resources. The scientific approach for decision making requires the use of one or more mathematical/optimization models (i.e. representations of the actual situation) to make the optimum decision.

An optimization model seeks to find the values of the decision variables that optimize (maximize or minimize) an objective function among the set of all values for the decision variables that satisfy the given constraints. Its three main components are:

  • Objective function: a function to be optimized (maximized or…


R for Marketing Analysis

Analyzing Customers’ Wants and Needs

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Kano Model

The Kano model was introduced by Noriaki Kano, a Japanese researcher and consultant that proposed a technique for helping companies and departments determine their customer’s satisfaction with products and services attributes.

The Kano model is based under three premises:

  • Customers’ satisfaction on a given product or service depends on the level of functionality provided.
  • Attributes can be classified into four main categories (excitement, performance, threshold and indifferent).
  • Customers’ feeling towards a particular attribute can be obtained via questionnaires.

The x-axis represents a product or service functionality, while the y-axis represents customers’ satisfaction level. …


Simulation Tutorials

Integrating Python with AnyLogic for Simulation Modeling

Python + AnyLogic

Python represents one of the world’s most popular programming languages. According to the analyst firm RedMonk, Python ranks second on the latest ranking of programming language popularity, just below JavaScript. Being a free open-source language, having a large variety of libraries for multiple purposes (e.g. data science, machine learning, artificial intelligence, big data, data visualization, optimization, statistics) and its compatibility with other programs have contributed to its increasing popularity among professionals and academics from multiple fields.

AnyLogic, a leading simulation software for business applications utilized worldwide by over 40% of Fortune 100 companies, has recently integrated a Python API to work on simulation models stored on your personal AnyLogic Cloud. This new functionality is expected to bring potential benefits to AnyLogic and Python users in the development, configuration and experimentation of their simulation models. …

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