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Articles on Trending Technologies
Technical articles with clear explanations and examples
How efficient is the k-medoids algorithm on large data sets?
A classic k-medoids partitioning algorithm like PAM works efficiently for small data sets but does not scale well for huge data sets. It can deal with higher data sets, a sampling-based method, known as CLARA (Clustering Large Applications), can be used.The approach behind CLARA is as follows: If the sample is chosen in a fairly random manner, it must closely define the original data set. The representative objects (medoids) chosen will be similar to those that would have been selected from the entire data set. CLARA draws several samples of the data set, applies PAM on each sample, and returns ...
Read MoreWhat are the requirements of clustering in data mining?
There are the following requirements of clustering in data mining which are as follows −Scalability − Some clustering algorithms work well on small data sets including fewer than some hundred data objects. A huge database can include millions of objects. Clustering on a sample of a given huge data set can lead to partial results. Highly scalable clustering algorithms are required.Ability to deal with different types of attributes − Some algorithms are designed to cluster interval-based (numerical) information. However, applications can require clustering several types of data, including binary, categorical (nominal), and ordinal data, or a combination of these data ...
Read MoreHow can we further improve the efficiency of Apriori-based mining?
There are some variations of the Apriori algorithm that have been projected that target developing the efficiency of the original algorithm which are as follows −The hash-based technique (hashing itemsets into corresponding buckets) − A hash-based technique can be used to decrease the size of the candidate k-itemsets, Ck, for k > 1. For instance, when scanning each transaction in the database to create the frequent 1-itemsets, L1, from the candidate 1-itemsets in C1, it can make some 2-itemsets for each transaction, hash (i.e., map) them into the several buckets of a hash table structure, and increase the equivalent bucket ...
Read MoreNode.js – detect_buffers Property in Redis
Node.js Redis offers certain properties which can be used as per your usecase. One such property is detect_buffers.If this property is set to True, then the replies that are sent to the callbacks are sent as buffers.This option lets you switch between the buffer and strings based upon this single command basis.This property does not work with pub-sub mode.SyntaxdetectBuffers: trueExample 1Create a file with the name "detectBuffers.js" and copy the following code. After creating the file, use the command "node detectBuffers.js" to run this code, as shown in the example below:// detect_buffers Property Demo Example // Importing the redis ...
Read MoreWhat are the Web-based tools in OLAP?
There are the various web-based tools which are as follows −Arbor Essbase Web − This tool provides features as drilling up, down, across; slice and dice, and powerful reporting, all for OLAP. It also provides data entry, such as full multi-user concurrent write capabilities. Arbor Essbase is only a server product, no user package exists, thus assuring its own desktop client version market. The Web product does not restore administrative and development structures but it restores only user access for queries and updates.Information Advantage Web OLAP − This product uses a server-centric messaging architecture, composed of a powerful analytic engine ...
Read MoreNode.js – Chalk Module
The chalk module is a third-party library that can be used for styling of texts. It allows the users to create their own themes in a Node.js project.This module helps the users to customize the response messages with different colors as per the preferences.It also improves the readability by providing colors and makes it easier to detect warnings and errors.Installationnpm install chalkExample 1Create a file with the name "chalk.js" and copy the following code. After creating the file, use the command "node chalk.js" to run this code as shown in the example below −// Importing the chalk module const chalk=require("chalk"); ...
Read MoreWhat are the characteristics of OLAP?
The FASMI TestIt can represent the characteristics of an OLAP application in a specific method, without dictating how it should be performed.Fast − It defines that the system is targeted to produce most responses to users within about five seconds, with the understandable analysis taking no more than one second and very few taking more than 20 seconds.Independent research in the Netherlands has shown that end-users consider that a process has declined if results are not received with 30 seconds, and they are suitable to hit ‘ALT+Ctrl+Delete’ unless the system needs them that the report will take longer.Analysis − It ...
Read MoreWhat are Hierarchical Methods?
A hierarchical clustering technique works by combining data objects into a tree of clusters. Hierarchical clustering algorithms are either top-down or bottom-up. The quality of an authentic hierarchical clustering method deteriorates from its inability to implement adjustment once a merge or split decision is completed.The merging of clusters is based on the distance among clusters. The broadly used measures for the distance between clusters are as follows, where mi is the mean for cluster Ci, ni is the number of points in Ci, and |p – p’| is the distance among two points p and p'.Types of Hierarchical Clustering MethodsThere ...
Read MoreNode.js – Process beforeExit Event
The 'beforeExit' event is called when Node.js empties its event loop and has no other work to schedule. The Node.js process exits normally when there is no work scheduled but a listener registered on the 'before exit' event can make async calls and thereby cause the Node.js process to continue.Example 1Create a file with the name "beforeExit.js" and copy the following code. After creating the file, use the command "node beforeExit.js" to run this code as shown in the example below −// process 'beforeExit' Demo Example // Importing the process module const process = require('process'); // Calling the ...
Read MoreNode.js – diffieHellman.getGenerator() Method
The diffieHellman.getGenerator() method returns the Diffie-Hellman generator in the specified encoding. A string is returned in case an encoding is passed, else a buffer is returned.SyntaxdiffieHellman.getGenerator([encoding])Parametersencoding - This parameter specifies the encoding of the return value.Example 1Create a file with the name "generator.js" and copy the following code. After creating the file, use the command "node generator.js" to run this code as shown in the example below:// diffieHellman.getPrime() Demo Example // Importing cryptoDiffieHellman from the crypto module const { createDiffieHellman } = require('crypto'); // Initializing the diffieHellman object const dh = createDiffieHellman(512); // Generate DiffieHellman's Generator ...
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