🔬Data Science: Bayesian Network (Definitions)

"A mathematic model in graphic form that represents a set of variables and their probabilistic independencies. It can be used, for example, to calculate the probability of a patient having a specific disease." (Attila Benko & Cecília S Lányi, "History of Artificial Intelligence", 2009) 

"A Bayesian network is a set of causally interrelated variables represented graphically in which the input information is generally subjective and can be updated in light of empirical data, by using Bayes’ theorem." (Herbert I Weisberg, "Bias and Causation: Models and Judgment for Valid Comparisons", 2010)

"A type of neural network. The Bayesian network is based on the fundamentals of probability theory." (Meta S Brown, "Data Mining For Dummies", 2014)

"A Bayesian network is a directed acyclical graph (there are no cycles in the graph) that is composed of three basic elements: 
nodes: each feature in a domain is represented by a single node in the graph.
edges: nodes are connected by directed links; the connectivity of the links in a graph encodes the influence and conditional independence relationships between nodes. 
conditional probability tables: each node has a conditional probability table (CPT) associated with it. A CPT lists the probability distribution of the feature represented by the node conditioned on the features represented by the other nodes to which a node is connected by edges." (John D Kelleher et al, "Fundamentals of Machine Learning for Predictive Data Analytics: Algorithms, worked examples, and case studies", 2015) 

"A representation of knowledge in the form of a directed acyclic graph representing random variables as nodes and their conditional dependencies as edges." (Petr Berka, "Machine Learning", 2015)

"They are acyclic graphical models that capture conditional dependence among random variables. Each node is associated with a function that gives the probability of finding the variable in a given state, given particular states of its parent variables." (Hamid R Arabnia et al, "Application of Big Data for National Security", 2015)

"A graph model representing random variables with their conditional dependencies." (David Natingga, "Data Science Algorithms in a Week" 2nd Ed., 2018)

"A particular type of statistical model that represents a set of variables and their conditional dependencies. It is usually used to make previsions in a great variety of events." (Gaetano B Ronsivalle & Arianna Boldi, "Artificial Intelligence Applied: Six Actual Projects in Big Organizations", 2019)

"A model that represents and calculates the probabilistic relationships between a set of random variables and an uncertain domain via a directed acyclic graph." (Accenture)

"Bayesian Neural Networks (BNNs) refers to extending standard networks with posterior inference in order to control over-fitting. From a broader perspective, the Bayesian approach uses the statistical methodology so that everything has a probability distribution attached to it, including model parameters (weights and biases in neural networks). In programming languages, variables that can take a specific value will turn the same result every-time you access that specific variable." (Databricks) [source]

🔬Data Science: Business Analysis (Definitions)

 "(1) The study of business processes, practices and business systems requirements. (2) The application of information to better understand business opportunities and challenges." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"A set of tools and methods used for execrating business insight making from the available data or system structure. It provide meaningful information with dynamic and sophisticate methods of problem solving such as optimization." (Shokoufeh Mirzaei, Defining a Business-Driven Optimization Problem, 2014)

"Business analytics is the combination of skills, technologies, applications, and processes used by organizations to gain insight into their business-based data and statistics to drive business planning." (K Hariharanath, "BIG Data: An Enabler in Developing Business Models in Cloud Computing Environments", 2019)

"It is the process of working with factual information in organizations, using suitable tools and techniques to identify the nuggets of wisdom (insights) from them that can have direct impact on influencing good decision making." (Tanushri Banerjee & Arindam Banerjee, "Designing a Business Analytics Culture in Organizations in India", 2021)

"Business analysis is the means through which operational problems and issues are systematically identified and investigated, different approaches are evaluated, and optimal solutions are determined." (Qlik) [source]

"The set of tasks, knowledge, tools and techniques required to identify business needs and determine solutions to business problems" (Business Analysis BOK) 

🔬Data Science: Delphi Method (Definitions)

"A qualitative forecasting method that seeks to use the judgment of experts systematically in arriving at a forecast of what future events will be or when they may occur. It brings together a group of experts who have access to each other's opinions in an environment where no majority opinion is disclosed." (Jae K Shim & Joel G Siegel, "Budgeting Basics and Beyond", 2008)

"A systematic forecasting practice that seeks input or advice from a panel of experts. Each expert provides their forecast input in a successive series of rounds, until consensus is achieved." (Steven Haines, "The Product Manager's Desk Reference", 2008)

"A systematic, interactive forecasting method that relies on a panel of experts. The experts answer questionnaires in two or more rounds. After each round, a facilitator provides an anonymous summary of the experts’ forecasts from the previous round as well as the reasons they provided for their judgments." (Project Management Institute, "Practice Standard for Project Estimating", 2010)

"Data collection method that happens in an anonymous fashion." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A structured communication technique used to conduct interactive forecasting. It involves a panel of experts." (IQBBA)

🔬Data Science: Descriptive Statistics (Definitions)

"Numbers that summarize how questionnaire items were answered. Descriptive statistics include frequency, percentage, cumulative frequency, and cumulative percentage." (Teri Lund & Susan Barksdale, "10 Steps to Successful Strategic Planning", 2006)

"Statistics that characterize the central tendency, variability, and shape of a variable." (Glenn J Myatt, "Making Sense of Data: A Practical Guide to Exploratory Data Analysis and Data Mining", 2006)

"Describe the values in a set. For example, if you sum a set of values, that sum is a descriptive statistic. If you find the largest value or the smallest value in a set of numbers, that’s also a descriptive statistic." (E C Nelson & Stephen L Nelson, "Excel Data Analysis For Dummies ", 2015)

"Those statistics or statistical procedures that summarise and/or describe the characteristics of a sample of scores." (K  N Krishnaswamy et al, "Management Research Methodology: Integration of Principles, Methods and Techniques", 2016)

🔬Data Science: Fuzzy Rule (Definitions)

"A conditional of the form IF X IS A, THEN Y IS B where A and B are fuzzy sets. In mathematical terms a rule is a relation between fuzzy sets. Each rule defines a fuzzy patch (the product A x B) in the system 'state space'. The wider the fuzzy sets A and B, the wider and more uncertain the fuzzy patch. Fuzzy rules are the knowledge-building blocks in a fuzzy system. In mathematical terms each fuzzy rule acts as an associative memory that associates the fuzzy response B with the fuzzy stimulus A." (Guido Deboeck & Teuvo Kohonen (Eds), "Visual Explorations in Finance with Self-Organizing Maps" 2nd Ed., 2000)

"In general, in rule-based systems, rules look something like: If A1 and A2 and … An then C1 and C2 and … Cm; where the Ai are the antecedents (conditions) on the left hand side (LHS) of the rule and the Cj are the consequents (conclusions) on the right hand side (RHS) of the rule. In this format, if all of the antecedents on the LHS of the rule are true then the rule will fire and the consequents will be asserted / executed. With Fuzzy rules both antecedents and conclusions can be of fuzzy nature." (Juan R González et al, Nature-Inspired Cooperative Strategies for Optimization, 2008)

"Fuzzy If-Then or fuzzy conditional statements are expressions of the form 'If A Then B', where A and B are labels of fuzzy sets characterised by appropriate membership functions. Due to their concise form, fuzzy If-Then rules are often employed to capture the imprecise modes of reasoning that play an essential role in the human ability to make decision in an environment of uncertainty and imprecision. The set of If-Then rules relate to a fuzzy logic system that are stored together is called a Fuzzy Rule Base." (Masoud Mohammadian, Supervised Learning of Fuzzy Logic Systems, 2009)

🔬Data Science: Hash Function (Definition)

"A function that maps a set of keys onto a set of addresses." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"A function that maps a string of arbitrary length to a fixed size value in a deterministic manner. Such a function may or may not have cryptographic applications." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

[cryptographic hash function:] "A function that takes an input string of arbitrary length and produces a fixed-size output for which it is unfeasible to find two inputs that map to the same output, and it is unfeasible to learn anything about the input from the output." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

[one-way hash function:] "A hash function for which it is computationally unfeasible to determine anything about the input from the output." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"A function that operates on an arbitrary-length input value and returns a fixed-length hash value." (Oracle, "Database SQL Tuning Guide Glossary", 2013)

[one-way hash:] "A one-way hash is an algorithm that transforms one string into another string (a fixed-length sequence of seemingly random characters) in such a way that the original string cannot be calculated by operations on the one-way hash value (i.e., the calculation is one way only). One-way hash values can be calculated for any string, including a person’s name, a document, or an image. For any input string, the resultant one-way hash will always be the same. If a single byte of the input string is modified, the resulting one-way hash will be changed and will have a totally different sequence than the one-way hash sequence calculated for the unmodified string. One-way hash values can be made sufficiently long (e.g., 256 bits) that a hash string collision (i.e., the occurrence of two different input strings with the same one-way hash output value) is negligible." (Jules H Berman, "Principles of Big Data: Preparing, Sharing, and Analyzing Complex Information", 2013)

"A hash function is an algorithm that maps from an input, for example, a string of characters, to an output string. The size of the input can vary, but the size of the output is always the same." (Dan Sullivan, "NoSQL for Mere Mortals®", 2015)

[one-way hash:] "Cryptographic process that takes an arbitrary amount of data and generates a fixed-length value. Used for integrity protection." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A function that takes as input the key of an element and produces an integer as output" (Nell Dale et al, "Object-Oriented Data Structures Using Java" 4th Ed., 2016)

"encryption methods that use no keys." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"A function that operates on an arbitrary-length input value and returns a fixed-length hash value." (Oracle, "Oracle Database Concepts")

🔬Data Science: Inference (Definitions)

"Drawing some form of conclusion about a measurable functional response based on representative or sample experimental data. Sample size, uncertainty, and the laws of probability play a major role in making inferences." (Clyde M Creveling, "Six Sigma for Technical Processes: An Overview for R Executives, Technical Leaders, and Engineering Managers", 2006)

"Reasoning from known propositions." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"In general, inference is the act or process of deriving new facts from facts known or assumed to be true. In Artificial Intelligence, researchers develop automated inference engines to automate human inference." (Michael Fellmann et al, "Supporting Semantic Verification of Process Models", 2012)

[statistical inference:] "A method that uses sample data to draw conclusions about a population." (Geoff Cumming, "Understanding The New Statistics", 2013)

"Any conclusion drawn on the basis of some set of information. In research, we draw inferences on the basis of empirical data we collect and ideas we construct." (K  N Krishnaswamy et al, "Management Research Methodology: Integration of Principles, Methods and Techniques", 2016)

[causal inference:] "Conclusion that changes in the independent variable resulted in a change in the dependent variable. It may be drawn only if all potential confounding variables are properly controlled." (K  N Krishnaswamy et al, "Management Research Methodology: Integration of Principles, Methods and Techniques", 2016)

"The process of using a probabilistic model to answer a query, given evidence." (Avi Pfeffer, "Practical Probabilistic Programming", 2016)

[inductive inference] "A machine learning method for learning the rules that produced the actual data." (David Natingga, "Data Science Algorithms in a Week" 2nd Ed., 2018)

"The ability to derive information not explicitly available." (Shon Harris & Fernando Maymi, "CISSP All-in-One Exam Guide" 8th Ed., 2018)

🔬Data Science: Data Modeling (Definitions)

"The task of developing a data model that represents the persistent data of some enterprise." (Keith Gordon, "Principles of Data Management", 2007)

"An analysis and design method, building data models to 

a) define and analyze data requirements,

b) design logical and physical data structures that support these requirements, and

c) define business and technical meta-data." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"The process of creating a data model by applying formal data model descriptions using data modeling techniques." (Christian Galinski & Helmut Beckmann, "Concepts for Enhancing Content Quality and eAccessibility: In General and in the Field of eProcurement", 2012)

"The process of creating the abstract representation of a subject so that it can be studied more cheaply (a scale model of an airplane in a wind tunnel), at a particular moment in time (weather forecasting), or manipulated, modified, and altered without disrupting the original (economic model)." (George Tillmann, "Usage-Driven Database Design: From Logical Data Modeling through Physical Schmea Definition", 2017)

"A method used to define and analyze the data requirements needed to support an entity’s business processes, defining the relationship between data elements and structures." (Solutions Review)

"A method used to define and analyze data requirements needed to support the business functions of an enterprise. These data requirements are recorded as a conceptual data model with associated data definitions. Data modeling defines the relationships between data elements and data structures. (Microstrategy)

"A method used to define and analyze data requirements needed to support the business functions of an enterprise. These data requirements are recorded as a conceptual data model with associated data definitions. Data modeling defines the relationships between data elements and structures." (Information Management)

"Refers to the process of defining, analyzing, and structuring data within data models." (Insight Software)

"Data modeling is a way of mapping out and visualizing all the different places that a software or application stores information, and how these sources of data will fit together and flow into one another." (Sisense) [source]

"Data modeling is the process of documenting a complex software system design as an easily understood diagram, using text and symbols to represent the way data needs to flow. The diagram can be used to ensure efficient use of data, as a blueprint for the construction of new software or for re-engineering a legacy application." (Techtarget) [source]

💎SQL Reloaded: Misusing Views and Pseudo-Constants

Views as virtual tables can be misused to replace tables in certain circumstances, either by storing values within one or multiple rows, like in the below examples:

-- parameters for a BI solution
CREATE VIEW dbo.vLoV_Parameters
AS
SELECT Cast('ABC' as nvarchar(20)) AS DataAreaId
 , Cast(GetDate() as Date) AS CurrentDate 
 , Cast(100 as int) AS BatchCount 

GO

SELECT *
FROM dbo.vLoV_Parameters

GO

-- values for a dropdown 
 CREATE VIEW dbo.vLoV_DataAreas
 AS
 SELECT Cast('ABC' as nvarchar(20)) AS DataAreaId
 , Cast('Company ABC' as nvarchar(50)) AS Description 
 UNION ALL
 SELECT 'XYZ' DataAreaId 
 , 'Company XYZ'

GO

SELECT *
FROM dbo.vLoV_DataAreas

GO

These solutions aren’t elegant, and typically not recommended because they go against one of the principles of good database design, namely “data belong in tables”, though they do the trick when needed. Personally, I used them only in a handful of cases, e.g. when it wasn’t allowed to create tables, when it was needed testing something for a short period of time, or when there was some overhead of creating a table for 2-3 values. Because of their scarce use, I haven’t given them too much thought, not until I discovered Jared Ko’s blog posting on pseudo-constants. He considers the values from the first view as pseudo-constants, and advocates for their use especially for easier dependency tracking, easier code refactoring, avoiding implicit data conversion and easier maintenance of values.

All these are good reasons to consider them, therefore I tried to take further the idea to see if it survives a reality check. For this I took Dynamics AX as testing environment, as it makes extensive use of enumerations (aka base enums) to store list of values needed allover through the application. Behind each table there are one or more enumerations, the tables storing master data abounding of them.  For exemplification let’s consider InventTrans, table that stores the inventory transactions, the logic that governs the receipt and issued transactions are governed by three enumerations: StatusIssue, StatusReceipt and Direction.

-- Status Issue Enumeration 
 CREATE VIEW dbo.vLoV_StatusIssue
 AS
 SELECT cast(0 as int) AS None
 , cast(1 as int) AS Sold
 , cast(2 as int) AS Deducted
 , cast(3 as int) AS Picked
 , cast(4 as int) AS ReservPhysical
 , cast(5 as int) AS ReservOrdered
 , cast(6 as int) AS OnOrder
 , cast(7 as int) AS QuotationIssue

GO

-- Status Receipt Enumeration 
 CREATE VIEW dbo.vLoV_StatusReceipt
 AS
SELECT cast(0 as int) AS None
 , cast(1 as int) AS Purchased
 , cast(2 as int) AS Received
 , cast(3 as int) AS Registered
 , cast(4 as int) AS Arrived
 , cast(5 as int) AS Ordered
 , cast(6 as int) AS QuotationReceipt

GO

-- Inventory Direction Enumeration 
 CREATE VIEW dbo.vLoV_InventDirection
 AS
 SELECT cast(0 as int) AS None
 , cast(1 as int) AS Receipt
 , cast(2 as int) AS Issue

 To see these views at work let’s construct the InventTrans table on the fly:

-- creating an ad-hoc table  
 SELECT *
 INTO  dbo.InventTrans
 FROM (VALUES (1, 1, 0, 2, -1, 'A0001')
 , (2, 1, 0, 2, -10, 'A0002')
 , (3, 2, 0, 2, -6, 'A0001')
 , (4, 2, 0, 2, -3, 'A0002')
 , (5, 3, 0, 2, -2, 'A0001')
 , (6, 1, 0, 1, 1, 'A0001')
 , (7, 0, 1, 1, 50, 'A0001')
 , (8, 0, 2, 1, 100, 'A0002')
 , (9, 0, 3, 1, 30, 'A0003')
 , (10, 0, 3, 1, 20, 'A0004')
 , (11, 0, 1, 2, 10, 'A0001')
 ) A(TransId, StatusIssue, StatusReceipt, Direction, Qty, ItemId)

 Here are two sets of examples using literals vs. pseudo-constants:

--example issued with literals 
SELECT top 100 ITR.*
 FROM dbo.InventTrans ITR
 WHERE ITR.StatusIssue = 1 
   AND ITR.Direction = 2

GO
 --example issued with pseudo-constants
 SELECT top 100 ITR.*
 FROM dbo.InventTrans ITR
      JOIN dbo.vLoV_StatusIssue SI
        ON ITR.StatusIssue = SI.Sold
      JOIN dbo.vLoV_InventDirection ID
        ON ITR.Direction = ID.Issue

GO

--example receipt with literals 
 SELECT top 100 ITR.*
 FROM dbo.InventTrans ITR
 WHERE ITR.StatusReceipt= 1
   AND ITR.Direction = 1

GO

--example receipt with pseudo-constants
 SELECT top 100 ITR.*
 FROM dbo.InventTrans ITR
      JOIN dbo.vLoV_StatusReceipt SR
        ON ITR.StatusReceipt= SR.Purchased
      JOIN dbo.vLoV_InventDirection ID
        ON ITR.Direction = ID.Receipt

 
As can be seen the queries using pseudo-constants make the code somehow readable, though the gain is only relative, each enumeration implying an additional join. In addition, when further business tables are added to the logic (e.g. items, purchases or sales orders)  it complicates the logic, making it more difficult to separate the essential from nonessential. Imagine a translation of the following query:

-- complex query 
  SELECT top 100 ITR.*
  FROM dbo.InventTrans ITR
              <several tables here>
  WHERE ((ITR.StatusReceipt<=3 AND ITR.Direction = 1)
    OR (ITR.StatusIssue<=3 AND ITR.Direction = 2))
    AND (<more constraints here>)

The more difficult the constraints in the WHERE clause, the more improbable is a translation of the literals into pseudo-constraints. Considering that an average query contains 5-10 tables, each of them with 1-3 enumerations, the queries would become impracticable by using pseudo-constants and quite difficult to troubleshoot their execution plans.

The more I’m thinking about, an enumeration data type as global variable in SQL Server (like the ones available in VB) would be more than welcome, especially because values are used over and over again through the queries. Imagine, for example, the possibility of writing code as follows:

-- hypothetical query
SELECT top 100 ITR.*
FROM dbo.InventTrans ITR
WHERE ITR.StatusReceipt = @@StatusReceipt .Purchased
  AND ITR.Direction = @@InventDirection.Receipt

From my point of view this would make the code more readable and easier to maintain. Instead, in order to make the code more readable, one’s usually forced to add some comments in the code. This works as well, though the code can become full of comments.

-- query with commented literals
SELECT top 100 ITR.*
FROM dbo.InventTrans ITR
WHERE ITR.StatusReceipt <=3 – Purchased, Received, Registered 
   AND ITR.Direction = 1-- Receip

In conclusion, pseudo-constants’ usefulness is only limited, and their usage is  against developers’ common sense, however a data type in SQL Server with similar functionality would make code more readable and easier to maintain.

PS: It is possible to simulate an enumeration data type in tables’ definition by using a CHECK constraint.

🔬Data Science: Data Exploration (Definitions)

Data exploration: "The process of examining data in order to determine ranges and patterns within the data." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

Data Exploration: "The part of the data science process where a scientist will ask basic questions that helps her understand the context of a data set. What you learn during the exploration phase will guide more in-depth analysis later. Further, it helps you recognize when a result might be surprising and warrant further investigation." (KDnuggets)

"Data exploration is the first step of data analysis used to explore and visualize data to uncover insights from the start or identify areas or patterns to dig into more." (Tibco) [source]

"Data exploration is the initial step in data analysis, where users explore a large data set in an unstructured way to uncover initial patterns, characteristics, and points of interest. This process isn’t meant to reveal every bit of information a dataset holds, but rather to help create a broad picture of important trends and major points to study in greater detail." (Sisense) [source]

"Data exploration is the process through which a data analyst investigates the characteristics of a dataset to better understand the data contained within and to define basic metadata before building a data model. Data exploration helps the analyst choose the most appropriate tool for data processing and analysis, and leverages the innate human ability to recognize patterns in data that may not be captured by analytics tools." (Qlik) [source]

"Data exploration provides a first glance analysis of available data sources. Rather than trying to deliver precise insights such as those that result from data analytics, data exploration focuses on identifying key trends and significant variables." (Xplenty) [source]

🔬Data Science: Data Preparation (Definitions)

Data preparation: "The process which involves checking or logging the data in; checking the data for accuracy; entering the data into the computer; transforming the data; and developing and documenting a database structure that integrates the various measures. This process includes preparation and assignment of appropriate metadata to describe the product in human readable code/format." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"Data Preparation describes a range of processing activities that take place in order to transform a source of data into a format, quality and structure suitable for further analysis or processing. It is often referred to as Data Pre-Processing due to the fact it is an activity that organises the data for a follow-on processing stage." (experian) [source]

"Data preparation [also] called data wrangling, it’s everything that is concerned with the process of getting your data in good shape for analysis. It’s a critical part of the machine learning process." (RapidMiner) [source]

"Data preparation is an iterative-agile process for exploring, combining, cleaning and transforming raw data into curated datasets for self-service data integration, data science, data discovery, and BI/analytics." (Gartner)

"Data preparation is the process of cleaning and transforming raw data prior to processing and analysis. It is an important step prior to processing and often involves reformatting data, making corrections to data and the combining of data sets to enrich data." (Talend) [source]

🔬Data Science: Data Augmentation (Definitions)

"1.The process of adding to something to make it more or greater than the original. 2.In logic, a relationship where if X leads to Y, then XZ will lead to YZ." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"A technique for improving the performance of a model by enriching the training data, e.g. by generating additional instances of minority classes."  (Vincent Karas & Björn W Schuller, "Deep Learning for Sentiment Analysis: An Overview and Perspectives", 2021)

🔬Data Science: Feature Extraction (Definitions)

"A technique that attempts to combine or transform predictors to make clear the information contained within them. Feature extraction methods include factor analysis, principal components analysis, correspondence analysis, multidimensional scaling, partial least square methods, and singular value decomposition." (Robert Nisbet et al, "Handbook of statistical analysis and data mining applications", 2009)

"Extracting or deriving some useful information from the initially obtained data." (Shouvik Chakraborty & Kalyani Mali, "An Overview of Biomedical Image Analysis From the Deep Learning Perspective", 2020)

"A process of finding features of words and map them to vector space." (Neha Garg & Kamlesh Sharma, "Machine Learning in Text Analysis", 2020)

"A digital signal processing algorithm, which extracts distinctive values from the input signal." (Andrej Zgank et al, "Embodied Conversation: A Personalized Conversational HCI Interface for Ambient Intelligence", 2021)

"Feature extraction is a procedure in dimensionality reduction of extracting principal variables (features) from some random variables under consideration, usually achieved by extracting one principal variable (feature) as mapping from multiple random variables." (Usama A Khan & Josephine M Namayanja, "Reevaluating Factor Models: Feature Extraction of the Factor Zoo", 2021)

🔬Data Science: Feature Selection (Definitions)

"A method by which to decide on which features (columns) to keep in the analysis that will be done by the data mining algorithms. One of the first things to be done in a data mining project; this uncovers the most important variables among the set of predictor variables. Many of the predictor variables in a data set may not really be important for making an accurate predictive model, and only dilute/reduce the accuracy score of the model if included." (Robert Nisbet et al, "Handbook of statistical analysis and data mining applications", 2009)

"The process a cybersecurity engineer uses to choose the features in which a given attack may manifest." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"Feature selection is the process of selecting important principal variables (features) from some random variables under consideration, usually achieved by selecting a principal variable (feature) as one of the random variables." (Usama A Khan & Josephine M Namayanja, "Reevaluating Factor Models: Feature Extraction of the Factor Zoo", 2021)

"It is used to select appropriate features from the available data for improving efficiency of machine learning algorithms." (Gunjan Ansari et al, "Natural Language Processing in Online Reviews", 2021)

🔬Data Science: Data Visualization (Definitions)

"Technique for presentation and analysis of data through visual objects, such as graphs, charts, images, and specialized tabular formats." (Paulraj Ponniah, "Data Warehousing Fundamentals", 2001)

"Technique for presentation and analysis of data through visual objects, such as graphs, charts, images, and specialized tabular formats." (Paulraj Ponniah, "Data Warehousing Fundamentals for IT Professionals", 2010) 

"Visual representation of data, aiming to convey as much information as possible through visual processes." (Alfredo Vellido & Iván Olie, "Clustering and Visualization of Multivariate Time Series", 2010)

"Techniques for graphical representation of trends, patterns and other information." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"Information abstracted in a schematic form to provide visual insights into sets of data. Data visualization enables us to go from the abstract numbers in a computer program (ones and zeros) to visual interpretation of data. Text visualization means converting textual information into graphic representation, so we can see information without having to read the data, as tables, histograms, pie or bar charts, or Cartesian coordinates." (Anna Ursyn, "Visualization as Communication with Graphic Representation", 2015)

"[...] data visualization [is] a tool that, by applying perceptual mechanisms to the visual representation of abstract quantitative data, facilitates the search for relevant shapes, order, or exceptions." (Jorge Camões, "Data at Work: Best practices for creating effective charts and information graphics in Microsoft Excel", 2016)

"Presenting data and summary information using graphics, animation, and three-dimensional displays. Tools for visually displaying information and relationships often using dynamic and interactive graphics." (Daniel J Power & Ciara Heavin, "Decision Support, Analytics, and Business Intelligence" 3rd Ed., 2017)

"Data Visualization is a way of representing the data collected in the form of figures and diagrams like tables, charts, graphs in order to make the data for common man more easily understandable." (Kirti R Bhatele, "Data Analysis on Global Stratification", 2020)

"Techniques for turning data into information by using the high capacity of the human brain to visually recognize patterns and trends. There are many specialized techniques designed to make particular kinds of visualization easy." (Information Management)

"The art of communicating meaningful data visually. This can involve infographics, traditional plots, or even full data dashboards." (KDnuggets)

"The practice of structuring and arranging data within a visual context to help users understand it. Patterns and trends that might be unrecognizable to the layman in text-based data can be easily viewed and digested by end users with the help of data visualization software." (Insight Software)

"Data visualization enables people to easily uncover actionable insights by presenting information and data in graphical, and often interactive graphs, charts, and maps." (Qlik) [source]

"Data visualization is the graphical representation of data to help people understand context and significance. Interactive data visualization enables companies to drill down to explore details, identify patterns and outliers, and change which data is processed and/or excluded." (Tibco) [source]

"Data visualization is the practice of translating information into a visual context, such as a map or graph, to make data easier for the human brain to understand and pull insights from." (Techtarget) [source]

"Data visualization is the process of graphically illustrating data sets to discover hidden patterns, trends, and relationships in order to develop key insights. Data visualization uses data points as a basis for the creation of graphs, charts, plots, and other images." (Talend) [source]

"Data visualization is the use of graphics to represent data. The purpose of these graphics is to quickly and concisely communicate the most important insights produced by data analytics." (Xplenty) [source]