scholarly journals Relational algebra and a point of view for using null value in a fuzzy database model.

2012 ◽  
Vol 17 (4) ◽  
Author(s):  
Hồ Thuần ◽  
Hồ Cẩm Hà
Keyword(s):  
Point Of View ◽  
Relational Algebra ◽  
Database Model ◽  
Fuzzy Database ◽  
Null Value

Extending the Relational Algebra for Relations with Maybe Tuples and Existential and Universal Null Values

1984 ◽  
Vol 7 (1) ◽  
pp. 129-150
Author(s):  
Joachim Biskup
Keyword(s):  
Relational Algebra ◽  
Null Value ◽  
Null Values ◽  
A Minor

We study operations on generalized database relations which possibly contain maybe tuples and two types of null values. The existential null value has the meaning “value at present unknown” whereas the universal null value has the meaning “value arbitrary”. For extending a usual relational operation to generalized relations we develop three requirements: adequacy, restrictedness, and feasibility. As demonstrated for the natural join as an example, we can essetially meet these requirements although we are faced with a minor tradeoff between restrictedness and feasibility.

Incomplete information in a relational database

1980 ◽  
Vol 3 (3) ◽  
pp. 363-377
Author(s):  
John Grant
Keyword(s):  
Incomplete Information ◽  
Relational Database ◽  
Functional Dependency ◽  
Relational Algebra ◽  
Database Model ◽  
Character String

In this paper we investigate the inclusion of incomplete information in the relational database model. This is done by allowing nonatomic entries, i.e. sets, as elements in the database. A nonatomic entry is interpreted as a set of possible elements, one of which is the correct one. We deal primarily with numerical entries where an allowed set is an interval, and character string entries. We discuss the various operations of the relational algebra as well as the notion of functional dependency for the database model.

scholarly journals Perancangan Aplikasi Rekomendasi Pemilihan Lokasi Rumah dengan Memanfaatkan Fuzzy Database Metode Tahani

Teknika ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 23-28
Author(s):  
Sathya Adi Dharma ◽  
Timothy John Pattiasina ◽  
Edwin Meinardi Trianto
Keyword(s):  
Database Model ◽  
Fuzzy Database

Pemilihan lokasi rumah memerlukan beberapa kriteria yang cocok dengan kebutuhan konsumen. Biasanya konsumen mencari informasi perumahan lewat brosur-brosur rumah atau mengunjungi pameran perumahan. Hal itu dirasa kurang efektif karena memerlukan waktu yang lama. Salah satu cara dalam menentukan lokasi rumah adalah dengan menggunakan fuzzy database dengan model Tahani. Fuzzy database model Tahani merupakan salah satu metode yang dapat digunakan pada proses pengambilan keputusan. Dalam penelitian ini, aplikasi fuzzy database model Tahani dibangun untuk membantu pihak agen perumahan dalam memberikan rekomendasi rumah kepada konsumen, sehingga konsumen dapat memilih rumah sesuai dengan kriteria yang dipilihnya dengan lebih cepat dan mudah. Pada aplikasi yang telah dibangun, hasil rekomendasi rumah didasarkan pada nilai derajat keanggotaan dan fire strength (nilai kebenaran) dari proses perhitungan di dalam aplikasi tersebut.

scholarly journals The interrelations between intersection, union and other signature operations in table algebra

2018 ◽  
Vol 32 ◽  
pp. 121-132 ◽  
Author(s):  
Alexey Senchenko
Keyword(s):  
Relational Database ◽  
Query Language ◽  
Standard Form ◽  
Point Of View ◽  
Relational Algebra ◽  
Equivalent Transformation ◽  
Table Algebras ◽  
Finite Set ◽  
Table Algebra ◽  
Almost All

Currently, databases are widely used in almost all areas of human activity. For all variety of different types of databases the most common are relational (table) databases, mathematical model of which was proposed by E. Codd. From mathematical point of view, a relational database is a finite set of finite relations between different predefined sets of basic data. Table algebra introduced by V.N. Red’ko and D.B. Buy is based on Codd’s relational algebra and significantly improves it. It formed the theoretical foundation of modern database query language. Elements of the carrier of table algebra specify relational data structures, and signature operations are based on the basic table manipulations in relational algebra and SQL-like languages. One of the most actual tasks in relational and table algebras is the problem of equivalent transformation of expressions in order to minimize or reduce them to a standard form; it is one of the stages of query optimization, and can also significantly reduce the processing time of information in relational database management systems. For the decision of this problem the interrelations between the basic table operations are used. In the present, a significant number of such interrelations have been established, most of which for the general case are performed as inclusions. The author has found criteria for the transition of some such inclusions into equalities. These criteria are expressed in terms of the active domains of the tables and are natural. In this paper, the interrelations of the intersection and the union of tables with other signature operations of table algebras: difference, selection, projection, saturation, active complement, join, renaming of attributes are considered.

scholarly journals Conservative Intensional Extension of Tarski's Semantics

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Zoran Majkić
Keyword(s):  
Free Algebra ◽  
Possible Worlds ◽  
Order Logic ◽  
Point Of View ◽  
Relational Algebra ◽  
First Order Logic ◽  
Cylindric Algebras ◽  
Possible World ◽  
Logic Formula ◽  
First Order

We considered an extension of the first-order logic (FOL) by Bealer's intensional abstraction operator. Contemporary use of the term “intension” derives from the traditional logical Frege-Russell doctrine that an idea (logic formula) has both an extension and an intension. Although there is divergence in formulation, it is accepted that the “extension” of an idea consists of the subjects to which the idea applies, and the “intension” consists of the attributes implied by the idea. From the Montague's point of view, the meaning of an idea can be considered as particular extensions in different possible worlds. In the case of standard FOL, we obtain a commutative homomorphic diagram, which is valid in each given possible world of an intensional FOL: from a free algebra of the FOL syntax, into its intensional algebra of concepts, and, successively, into an extensional relational algebra (different from Cylindric algebras). Then we show that this composition corresponds to the Tarski's interpretation of the standard extensional FOL in this possible world.

scholarly journals Learning algorithm analysis for deep neural network with ReLu activation functions

2018 ◽  
Vol 19 ◽  
pp. 01009
Author(s):  
Stanisław Płaczek ◽  
Aleksander Płaczek
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Learning Algorithm ◽  
Activation Function ◽  
Point Of View ◽  
Algorithm Analysis ◽  
Theoretic Point ◽  
Neural Network Structure ◽  
Null Value ◽  
Hidden Layer

In the article, emphasis is put on the modern artificial neural network structure, which in the literature is known as a deep neural network. Network includes more than one hidden layer and comprises many standard modules with ReLu nonlinear activation function. A learning algorithm includes two standard steps, forward and backward, and its effectiveness depends on the way the learning error is transported back through all the layers to the first layer. Taking into account all the dimensionalities of matrixes and the nonlinear characteristics of ReLu activation function, the problem is very difficult from a theoretic point of view. To implement simple assumptions in the analysis, formal formulas are used to describe relations between the structure of every layer and the internal input vector. In practice tasks, neural networks’ internal layer matrixes with ReLu activations function, include a lot of null value of weight coefficients. This phenomenon has a negatives impact on the effectiveness of the learning algorithm convergences. A theoretical analysis could help to build more effective algorithms.

DEALING WITH DISJUNCTIVE AND MISSING INFORMATION IN LOGIC FUZZY DATABASES

1996 ◽  
Vol 04 (02) ◽  
pp. 177-201 ◽  
Author(s):  
O. PONS ◽  
J.C. CUBERO ◽  
J.M. MEDINA ◽  
M.A. VILA
Keyword(s):  
Incomplete Information ◽  
General Term ◽  
Missing Information ◽  
Database Model ◽  
Fuzzy Database

This work is concerned with the problem of representing and handling disjunctive and missing information in the framework of logic fuzzy databases. We use the general term of incomplete information to refer both disjunctive or missing information. To pose the problem, we firstly give a brief summary about the underlying Logic Fuzzy Database Model. Starting from the concept of logic fuzzy database, which is a general fuzzy database that can be represented in a logic framework, we see how disjunctive and missing information can be represented and handled.

scholarly journals SISTEM PENDUKUNG KEPUTUSAN PENENTUAN CALON PENERIMA BEASISWA MENGGUNAKAN METODE FUZZY DATABASE MODEL TAHANI

2016 ◽  
Vol 7 (2) ◽  
pp. 449
Author(s):  
Ardi Sanjaya ◽  
Risaniatin Ningsih
Keyword(s):  
Database Model ◽  
Fuzzy Database

Pada penelitian ini dibuat suatu sistem informasi berupa pendukung keputusan untuk menentukan calon penerima beasiswa menggunakan metode fuzzy database model Tahani. Penelitian ini dilakukan pada Sekolah Menengah Kejuruan (SMK) PGRI 4 Kota Kediri. Tujuan dari penelitian ini adalah untuk publikasi ilmiah dan untuk pembuatan sistem guna memberikan suatu pendukung keputusan berupa pengurutan data siswa berdasar kriteria tertentu sebagai prioritas untuk menerima beasiswa. Dengan memanfaatkan database siswa yang ada seperti data penghasilan orang tua, data prestasi, data jarak rumah kesekolah, dan sejenisnya, maka pihak sekolah akan lebih mudah untuk mengolah data siswa dalam memilih calon-calon penerima beasiswa dengan menggunakan sistem pendukung keputusan ini. Jika hanya menggunakan database standar akan kesulitan untuk menentukan calon-calon penerima beasiswa sebab pada database standar bersifat pasti, deterministik dan presisi. Namun pada kenyataannya pengolahan data yang ada lebih bersifat samar (fuzzy). Misalnya kriteria jarak rumah yang dikategorikan dekat, sedang dan jauh. Sedangkan pada database data jarak rumah berisi nilai pasti. Hasil dari penelitian ini adalah telah berhasil dibuat suatu sistem informasi pengolahan data siswa sebagai pendukung keputusan penentuan calon penerima beasiswa. Informasi yang dihasilkan salah satunya adalah urutan prioritas calon penerima beasiswa sehingga proses penentuan calon penerima beasiswa diharapkan dapat dikerjakan lebih efektif dan efisien. Kata kunci: sistem pendukung keputusan, fuzzy database model tahani.

scholarly journals RANCANG BANGUN APLIKASI REKOMENDASI PEMBELIAN LAPTOP DENGAN METODE FUZZY DATABASE MODEL TAHANI BERBASIS WEB

2014 ◽  
Vol 3 (2) ◽  
pp. 86-95
Author(s):  
Hendry Setiawan ◽  
Seng Hansun
Keyword(s):  
Fuzzy Logic ◽  
Data Storage ◽  
Programming Language ◽  
Consumer Finance ◽  
Web Based ◽  
Database Model ◽  
Standard Relation ◽  
Fuzzy Database

A laptop is a computer that looks compact, small, lightweight and easy to carry anywhere. But choosing a laptop is not an easy thing for consumers who want to have a laptop as per the specifications and budget of the consumer finance. Therefore the purpose of this research is to build a web-based application that can give recommendation to purchasers or consumers as needed. The application is built by using PHP programming language and implementing the Fuzzy Database Tahani model which is still using the standard relation of fuzzy logic, and also using MySQL database for the data storage. It is found that the Fuzzy Database Tahani model can be implemented on the application built on to give a correct recommendation for the consumers.

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