An inverted file indexes a text collection to speed up searching. It contains a vocabulary of distinct words and occurrences lists with information on where each word appears. For each term in the vocabulary, it stores a list of pointers to occurrences called an inverted list. Coarser granularity indexes use less storage but require more processing, while word-level indexes enable proximity searches but use more space. The document describes how inverted files are structured and constructed from text and discusses techniques like block addressing that reduce their space requirements.
The (standard) Boolean model of information retrieval (BIR) is a classical information retrieval (IR) model and, at the same time, the first and most-adopted one. ... The BIR is based on Boolean logic and classical set theory in that both the documents to be searched and the user's query are conceived as sets of terms.
Vector space model or term vector model is an algebraic model for representing text documents as vectors of identifiers, such as, for example, index terms. It is used in information filtering, information retrieval, indexing and relevancy rankings. Its first use was in the SMART Information Retrieval System
Indexing is used to speed up access to desired data.
E.g. author catalog in library
A search key is an attribute or set of attributes used to look up records in a file. Unrelated to keys in the db schema.
An index file consists of records called index entries.
An index entry for key k may consist of
An actual data record (with search key value k)
A pair (k, rid) where rid is a pointer to the actual data record
A pair (k, bid) where bid is a pointer to a bucket of record pointers
Index files are typically much smaller than the original file if the actual data records are in a separate file.
If the index contains the data records, there is a single file with a special organization.
TF-IDF, short for Term Frequency - Inverse Document Frequency, is a text mining technique, that gives a numeric statistic as to how important a word is to a document in a collection or corpus. This is a technique used to categorize documents according to certain words and their importance to the document
The (standard) Boolean model of information retrieval (BIR) is a classical information retrieval (IR) model and, at the same time, the first and most-adopted one. ... The BIR is based on Boolean logic and classical set theory in that both the documents to be searched and the user's query are conceived as sets of terms.
Vector space model or term vector model is an algebraic model for representing text documents as vectors of identifiers, such as, for example, index terms. It is used in information filtering, information retrieval, indexing and relevancy rankings. Its first use was in the SMART Information Retrieval System
Indexing is used to speed up access to desired data.
E.g. author catalog in library
A search key is an attribute or set of attributes used to look up records in a file. Unrelated to keys in the db schema.
An index file consists of records called index entries.
An index entry for key k may consist of
An actual data record (with search key value k)
A pair (k, rid) where rid is a pointer to the actual data record
A pair (k, bid) where bid is a pointer to a bucket of record pointers
Index files are typically much smaller than the original file if the actual data records are in a separate file.
If the index contains the data records, there is a single file with a special organization.
TF-IDF, short for Term Frequency - Inverse Document Frequency, is a text mining technique, that gives a numeric statistic as to how important a word is to a document in a collection or corpus. This is a technique used to categorize documents according to certain words and their importance to the document
We have hundreds of customers, each of whom may have dozens of shards. To manage this explosion of indexes, I'll describe how we're using Solr Cloud to manage every index - from creation, through migration from box to box, and finally destruction. I'll describe some of the performance issues we had to deal with, especially with ZooKeeper.
Slides for VU Web Technology course lecture on "Search on the Web". Explaining how search engines work, some basic information laws and inverted indices.
Discusses the concept of information seeking and 3 approaches to understanding it: Belkin's ASK hypothesis, Kuhlthau's Information Search Process and Dervin's Sense-Making.
Practical Elasticsearch - real world use casesItamar
Elasticsearch - a search and real-time analytics server based on Apache Lucene - is gaining a lot of popularity lately, and is being used world-wide to power many sophisticated systems. While many use it for the "standard" stuff (that is, simple full-text search and real-time log analysis), there are some really interesting usage patterns that can prove useful in many real-world scenarios. In this talk we will briefly talk about Elasticsearch and its common use-cases, and then showcase some less common use-cases leveraging Elasticsearch in an interesting and often times innovating ways.
Apache LuceneTM is a free open-source , high-performance, full-featured text search engine library that has been written completely in Java. As a technology is best suited for any application that requires full-text search, especially cross-platform.
Zoe Slattery's slides from PHPNW08:
The ability to store large quantities of local data means that many applications require some form of text search and retrieval facility. From the point of view of the application developer there are a number of choices to make, the first is whether to use a complete packaged solution or whether to use one of the available information libraries to build a custom information retrieval (IR) solution. In this talk I’ll look at the options for PHP programmers who choose to embed IR facilities within their applications.
For Java programmers there is clearly a good range of options for text retrieval libraries, but options for PHP programmers are more limited. At first sight for a PHP programmer wishing to embed indexing and search facilities in their application, the choice seems obvious - the PHP implementation of Lucene (Zend Search Lucene). There is no requirement to support another language, the code is PHP therefore easy for PHP programmers to work with and the license is commercially friendly. However, whilst ease of integration and support are key factors in choice of technology, performance can also be important; the performance of the PHP implementation of Lucene is poor compared to the Java implementation.
In this talk I’ll explain the differences in performance between PHP implementation of Lucene and the Java implementation and examine the other options available to PHP programmers for whom performance is a critical factor.
Munching & crunching - Lucene index post-processingabial
Lucene EuroCon 10 presentation on index post-processing (splitting, merging, sorting, pruning), tiered search, bitwise search, and a few slides on MapReduce indexing models (I ran out of time to show them, but they are there...)
A SECURE AND DYNAMIC MULTI-KEYWORD RANKED SEARCH SCHEME OVER ENCRYPTED CLOUD...Nexgen Technology
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File is the basic unit of information storage on a secondary storage device. Therefore, almost every form of data and information reside on these devices in form of file – whether audio data or video, whether text or binary.
Files may be classified on different bases as follows:
1. On the basis of content:
Text files: Files containing data/information in textual form. It is merely a collection of characters. Document files etc.
Binary files: Files containing machine code. The contents are non-recognizable and can be interpreted only in a specified way using the same application that created it. E.g. executable program files, audio files, video files etc.
Ch 17 disk storage, basic files structure, and hashingZainab Almugbel
Modified version of Chapter 17 of the book Fundamentals_of_Database_Systems,_6th_Edition with review questions
as part of database management system course
Survey On Building A Database Driven Reverse DictionaryEditor IJMTER
Reverse dictionaries are widely used for a reference work that is organized by concepts,
phrases, or the definitions of words. This paper describe the many challenges inherent in building a
reverse lexicon, and map drawback to the well known abstract similarity problem The criterion web
search engines are basic versions of system; they take benefit of huge scale which permits inferring
general interest concerning documents from link information. This paper describe the basic study of
database driven reverse dictionary using three large-scale dataset namely person names, general English
words and biomedical concepts. This paper analyzes difficulties arising in the use of documents
produced by Reverse dictionary.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Immunizing Image Classifiers Against Localized Adversary Attacks
Inverted index
1.
2. Definition: an inverted file is a word-oriented
mechanism for indexing a text collection in
order to speed up the searching task.
Structure of inverted file:
◦ Vocabulary: is the set of all distinct words in the
text
◦ Occurrences: lists containing all information
necessary for each word of the vocabulary (text
position, frequency, documents where the word
appears, etc.)
3. Inverted file index is list of terms that appear in the
document collection (called a lexicon or vocabulary) and
for each term in the lexicon, stores a list of pointers to all
occurrences of that term in the document collection. This
list is called an inverted list.
Granularity of an index determines the accuracy of
representation of the location of the word
◦ Coarse-grained index requires less storage and more
query processing to eliminate false matches
◦ Word-level index enables queries involving adjacency
and proximity, but has higher space requirements
5. 5
Text:
Inverted file
1 6 12 16 18 25 29 36 40 45 54 58 66 70
That house has a garden. The garden has many flowers. The flowers are
beautiful
beautiful
flowers
garden
house
70
45, 58
18, 29
6
Vocabulary Occurrences
6. Prior example allows for boolean
queries.
Need the document frequency and term
frequency.
Vocabulary entry Posting file entry
k dk doc1 f1k doc2 f2k …
dk : document frequency of term k
doci : i-th document that contains term k
fik : term frequency of term k in document i
7. The space required for the vocabulary is rather
small. According to Heaps’ law the vocabulary
grows as O(nβ
), where β is a constant between
0.4 and 0.6 in practice
◦ TREC-2: 1 GB text, 5 MB lexicon
On the other hand, the occurrences demand
much more space. Since each word appearing
in the text is referenced once in that structure,
the extra space is O(n)
To reduce space requirements, a technique
called block addressing is used
8. The text is divided in blocks
The occurrences point to the blocks where the
word appears
Advantages:
◦ the number of pointers is smaller than positions
◦ all the occurrences of a word inside a single block
are collapsed to one reference
Disadvantages:
◦ online search over the qualifying blocks if exact
positions are required
9. Text:
Inverted file
beautiful
flowers
garden
house
4
3
2
1
Vocabulary Occurrences
Block 1 Block 2 Block 3 Block 4
That house has a garden. The garden has many flowers. The flowers are
beautiful
10. How big are inverted files?
◦ In relation to original collection size
right column indexes stopwords while left removes
stopwords
Blocks require text to be available for location of
terms within blocks.
45%
27%
18%
73%
41%
25%
36%
18%
1.7%
64%
32%
2.4%
35%
5%
0.5%
63%
9%
0.7%
Addressing words
Addressing 256 blocks
Addressing 64K blocks
Index Small collection
(1Mb)
Medium collection
(200Mb)
Large collection
(2Gb)
11. The search algorithm on an inverted
index follows three steps:
1. Vocabulary search: the words present in
the query are located in the vocabulary
2. Retrieval occurrences: the lists of the
occurrences of all query words found are
retrieved
3. Manipulation of occurrences: the
occurrences are processed to solve the
query
12. Searching inverted files starts with vocabulary
◦ store the vocabulary in a separate file
Structures used to store the vocabulary
include
◦ Hashing : O (1) lookup, does not support range
queries
◦ Tries : O (c) lookup, c = length (word)
◦ B-trees : O (log v) lookup
An alternative is simply storing the words in
lexicographical order
◦ cheaper in space and very competitive with O(log
v) cost
13. All the vocabulary is kept in a suitable data
structure storing for each word and a list of
its occurrences
Each word of each text in the corpus is
read and searched for in the vocabulary
If it is not found, it is added to the
vocabulary with a empty list of occurrences
The new position is added to the end of its
list of occurrences for the word
14. Once the text is exhausted the vocabulary is
written to disk with the list of occurrences.
Two files are created:
◦ in the first file, each list of word occurrences is
stored contiguously
◦ in the second file, the vocabulary is stored in
lexicographical order and, for each word, a pointer
to its list in the first file is also included. This allows
the vocabulary to be kept in memory at search time
The overall process is O(n) worst-case time
15. An option is to use the previous algorithm until
the main memory is exhausted. When no
more memory is available, the partial index Ii
obtained up to now is written to disk and
erased the main memory before continuing
with the rest of the text
Once the text is exhausted, a number of
partial indices Ii exist on disk
The partial indices are merged to obtain the
final index
16. I 1...8
I 1...4 I 5...8
I 1...2 I 3...4 I 5...6 I 7...8
I 1 I 2 I 3 I 4 I 5 I 6 I 7 I 8
1 2 4 5
3 6
7
final index
initial dumps
level 1
level 2
level 3
17. The total time to generate partial indices is
O(n)
The number of partial indices is O(n/M)
To merge the O(n/M) partial indices are
necessary log2(n/M) merging levels
The total cost of this algorithm is O(n log(n/M))
18. Inverted files are used to index text
The indices are appropriate when the
text collection is large and semi-static
If the text collection is volatile online
searching is the only option
Some techniques combine online and
indexed searching
19. Vocabulary List
◦ Text preprocessing modules
lexical analysis, stemming, stopwords
Occurrences of Vocabulary Terms
◦ Inverted index creation
term frequency in documents, document frequency
Retrieval and Ranking Algorithm
Query and Ranking Interfaces
Browsing/Visualization Interface