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.

Using the whole image and restrictions in the research of properties of some signature operations in Table Algebra

2019 ◽  
Vol 33 ◽  
pp. 112-121
Author(s):  
Nadiya Kakhuta ◽  
Alexey Senchenko
Keyword(s):  
Binary Relation ◽  
Relational Databases ◽  
Query Language ◽  
Relational Algebra ◽  
General Interest ◽  
Table Algebras ◽  
Modern Analogue ◽  
Table Data ◽  
Table Algebra ◽  
Composition Of Relations

The features of the whole image relative to many binary relation, and restrictions on a binary relation on the set for some of the signature operations of Table Algebra are used in the work. Constructions of the whole image and restrictions are of general interest for Mathematics, and Table Algebra is a modern analogue of Codd's well-known Relational Algebra. It forms the theoretical foundation of modern query language databases. Elements of the carrier of Table Algebra specify relational table data structures, and signature operations are based on the basic table manipulations in Relational Algebra and SQL-like languages. The following results in the research of the features of the whole image were obtained: interconnections between the whole image and restrictions were found; the monotony and distribution of the whole image and restrictions on unions, a criterion of their emptiness and interconnections with first and second projection relations were proved; the whole image of the composition of relations and composition restrictions were found; the distribution of restriction on intersection of sets was set; the estimates of the distribution of the whole image of intersection and difference of sets were given; criteria for distribution of the whole image relative to the intersection and differences of sets were found. In addition, the clues were provided with the help of the whole image and restrictions on some of the signature operations of Table Algebra: intersection, union, difference, projection and joining. These representations allowed us to obtain some features of these operations, which derive directly from the features of the whole image and restrictions. It is supposed to get similar views on other signature operations of Table Algebras and to allocate their features arising from such representation. The obtained results can be used in the theory of Table Algebra as an approach to the research of the features of their signature operations, this can be used in query optimization in relational databases.

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 How ethical challenges of covert observations can be met in practice

2021 ◽  
pp. 174701612110082
Author(s):  
Nicole Podschuweit
Keyword(s):  
Social Research ◽  
Role Playing ◽  
Great Distance ◽  
Point Of View ◽  
Ethical Challenges ◽  
Research Subjects ◽  
Written Information ◽  
Ethical Debate ◽  
The People ◽  
Almost All

This paper aims to bring into the ethical debate on covert research two aspects that are neglected to date: the perspective of the research subjects and the special responsibility of investigators towards their observers. Both aspects are falling behind, especially in quantitative social research. From a methodological point of view, quantitative forms of covert observation involve a great distance between the researcher and the research subjects. When human observers are involved, the focus is usually on the reliable application of the measuring instrument. Therefore, herein, a quantitative study is used as an example to show how the protection needs of both the observed persons and the observers can be met in practice. The study involved 40 student observers who covertly captured everyday conversations in real-world settings (e.g. in cafés or trains) by a highly standardised observation scheme. The study suggests that the anonymity of the research subjects and their trust in the observers are crucial for their subsequent consent. However, many participants showed only little or even no interest in the written information they were provided. Further, this study strongly emphasises how mentally stressful covert observations are to the observers. Almost all observers were worried in advance that the people they were observing would prematurely blow their cover and confront them. Role-playing and in-depth discussions in teams are good strategies to alleviate such and other fears and to prepare student assistants well for their demanding work in the field.

Consistency conditions for a finite set of projections of a function

1979 ◽  
Vol 85 (1) ◽  
pp. 61-68 ◽  
Author(s):  
K. J. Falconer
Keyword(s):  
Lebesgue Measure ◽  
Convex Subset ◽  
Compact Convex ◽  
Unit Vector ◽  
Compact Convex Subset ◽  
Finite Collection ◽  
Finite Set ◽  
Almost All ◽  
Dimensional Lebesgue Measure ◽  
Unit Vectors

Let H(μ, θ) be the hyperplane in Rn (n ≥ 2) that is perpendicular to the unit vector 6 and perpendicular distance μ from the origin; that is, H(μ, θ) = (x ∈ Rn: x. θ = μ). (Note that H(μ, θ) and H(−μ, −θ) are the same hyperplanes.) Let X be a proper compact convex subset of Rm. If f(x) ∈ L1(X) we will denote by F(μ, θ) the projection of f perpendicular to θ; that is, the integral of f(x) over H(μ, θ) with respect to (n − 1)-dimensional Lebesgue measure. By Fubini's Theorem, if f(x) ∈ L1(X), F(μ, θ) exists for almost all μ for every θ. Our aim in this paper is, given a finite collection of unit vectors θ1, …, θN, to characterize the F(μ, θi) that are the projections of some function f(x) with support in X for 1 ≤ i ≤ N.

scholarly journals Asymptotic relative submajorization of multiple-state boxes

2021 ◽  
Vol 111 (4) ◽  
Author(s):  
Gergely Bunth ◽  
Péter Vrana
Keyword(s):  
Hypothesis Testing ◽  
Null Hypothesis ◽  
Alternative Hypothesis ◽  
Standard Form ◽  
Point Of View ◽  
State Discrimination ◽  
Simple Alternative ◽  
Multiple State ◽  
Error Probabilities

AbstractPairs of states, or “boxes” are the basic objects in the resource theory of asymmetric distinguishability (Wang and Wilde in Phys Rev Res 1(3):033170, 2019. 10.1103/PhysRevResearch.1.033170), where free operations are arbitrary quantum channels that are applied to both states. From this point of view, hypothesis testing is seen as a process by which a standard form of distinguishability is distilled. Motivated by the more general problem of quantum state discrimination, we consider boxes of a fixed finite number of states and study an extension of the relative submajorization preorder to such objects. In this relation, a tuple of positive operators is greater than another if there is a completely positive trace nonincreasing map under which the image of the first tuple satisfies certain semidefinite constraints relative to the other one. This preorder characterizes error probabilities in the case of testing a composite null hypothesis against a simple alternative hypothesis, as well as certain error probabilities in state discrimination. We present a sufficient condition for the existence of catalytic transformations between boxes, and a characterization of an associated asymptotic preorder, both expressed in terms of sandwiched Rényi divergences. This characterization of the asymptotic preorder directly shows that the strong converse exponent for a composite null hypothesis is equal to the maximum of the corresponding exponents for the pairwise simple hypothesis testing tasks.

Bona fides and ubuntu – A response to Dale Hutchison

Acta Juridica ◽  
2021 ◽  
Vol 2021 ◽  
pp. 85-106
Author(s):  
J Barnard-Naudé
Keyword(s):  
South African ◽  
Common Law ◽  
Standard Form ◽  
Contract Law ◽  
Law School ◽  
Point Of View ◽  
Long Time ◽  
School Faculty ◽  
The Common ◽  
Faculty Meeting

This paper is a response to Dale Hutchison’s recent arguments about the role of fairness in contract law after the Constitution. From the point of view of transformative constitutionalism, the paper argues that the fairness ‘debate’ in the South African law of contract should be approached as what it so patently is, namely, as evidence of a deep ideological conflict that has existed in our law of contract for a very long time, and that this debate now exists within the context of a larger debate about the appropriate transformative reach of the Constitution. The argument takes the form of two ‘dangerous supplements’ to Hutchison’s discourse. The first of these supplements contends that indeterminacy is a symptom of the common law itself, rather than a result of contract law’s contact with the Constitution. The second dangerous supplement suggests a responsible judicial engagement with bona fides and ubuntu, one that can exploit the strengths of both the common law and the Constitution and that understands good faith and ubuntu to be ‘inter-linking’ constitutional values that should be enlisted in unison or at least in resonance when it comes to the question of fairness in our contemporary law of contract. In conclusion, I offer a reading of Hutchison’s own politics of contract law and contend that his is an altruistic politics committed to the standard form. I contend that this politics of contract law is consistent with a transformative understanding of the post-apartheid legal order. ‘Law, like every other cultural institution, is a place where we tell one another stories about our relationships with ourselves, one another, and authority. In this, law is no different from the Boston Globe, the CBS evening news, Mother Jones, or a law school faculty meeting. When we tell one another stories, we use languages and themes that different pieces of the culture make available to us, and that limit the stories we can tell. Since our stories influence how we imagine, as well as how we describe, our relationships, our stories also limit who we can be’.

Bernhard Riemann’s legacy of 1859

2009 ◽  
Vol 93 (528) ◽  
pp. 468-475
Author(s):  
Graham Hoare
Keyword(s):  
Number Theory ◽  
Mathematical Physics ◽  
Point Of View ◽  
German Version ◽  
Profound Impact ◽  
Almost All ◽  
University Of Göttingen ◽  
The University ◽  
Modern Mathematics ◽  
Mathematics And Physics

The German version of Riemann’s Collected Works is confined to a single volume of 690 pages. Even so, this volume has had an abiding and profound impact on modern mathematics and physics, as we shall see. In fifteen years of activity, from 1851, when he gained his doctorate at the University of Göttingen, to his death in 1866, two months short of his fortieth birthday, Riemann contributed to almost all areas of mathematics. He perceived mathematics from the analytic point of view and used analysis to illuminate subjects as diverse as number theory and geometry. Although regarded principally as a mathematician Riemann had an abiding interest in physics and researched significantly in the methods of mathematical physics, particularly in the area of partial differential equations.

scholarly journals Social Order and Practical Wisdom of Walking in a Crowd

2018 ◽  
Vol 24 (4) ◽  
pp. 8-29
Author(s):  
Andrei M. Korbut
Keyword(s):  
Social Order ◽  
Practical Wisdom ◽  
Point Of View ◽  
Joint Production ◽  
Social Phenomena ◽  
Social Transformations ◽  
Sociological Approach ◽  
Everyday Practices ◽  
Phenomenal Field ◽  
Almost All

The article suggests returning to the “crowd” as an object of sociological analysis. Crowds have attracted early sociologists because crowds were visual embodiments of social forces that surpass individuals and also served as a symbol of the profound social transformations which were taking place in the late 19th and early 20th centuries. Analyzing crowds allowed for the first sociologists (G. Simmel, R. Park, M. Weber, E. Durkheim) to oppose the psychological interpretation of mass social phenomena with a purely sociological approach. However, in the second half of the 20th century sociologists had lost almost all interest in the crowd, as it did not meet the interests of researchers of “large” social structures, nor the interests of the proponents of interactionist approaches. This article shows that the crowd can again be made interesting for sociology if we were to consider it from the point of view of the everyday practices of the participants. In these everyday practices a specific form of phronesis, i.e. practical wisdom, technical skill coupled with moral judgment about which action is good and which is not, is implemented. It is shown here that the study of the practical wisdom of walking in a crowd requires special concepts and methods that can be found in phenomenology and ethnomethodology. The article suggests using three such concepts for the analysis of crowds: phenomenal field, oriented object, and figuration of details. With the help of these concepts, the methods of the crowd’s situated social order production are analyzed in relation to the management of speed and trajectories of movement, following one another, walkers’ stopping and slowing down, and joining the crowd. This analysis shows that the joint production of the crowd’s social order by its participants is a situated practice, i.e. it consists of making the local scenes of everyday life familiar and accountable, and of assessing the local adequacy of the actions performed.

scholarly journals SISI NEGATIF GAME ONLINE PERSPEKTIF ISLAM DAN PSIKOLOGI ISLAM

2021 ◽  
Vol 5 (2) ◽  
pp. 153
Author(s):  
Khotibul Umam ◽  
Abdul Muhid
Keyword(s):  
Literature Review ◽  
Life Style ◽  
Negative Impact ◽  
Technological Development ◽  
Human Life ◽  
Online Games ◽  
Point Of View ◽  
Technological Advances ◽  
Islamic Psychology ◽  
Almost All

Technological development has changed human life style. Child's world that was once filled with traditional games has now been eroded by technological advances. Nowadays online games that replace traditional games are not only favored by children, almost all levels of human age like playing online games. But behind it all there is a negative impact that haunts its users. This study aims to reveal the negative side of using online games from the point of view of Islam and Islamic Psychology. The technique used is literature review by compiling some previous articles. The results showed that excessive use of online games will give a bad impact on the physical and psychological users, such as visual impairment, sleep disturbance, addiction, violence and stress. The use of online games is also considered more disadvantage than the benefits and it’s seen as an activity that wastes time, and it is prohibited in Islam.

scholarly journals Complexes for continuous monitoring of drilling fluid parameters during drilling

2021 ◽  
Vol 6 (3) ◽  
pp. 144-151
Author(s):  
Sergey V. Lakhtionov ◽  
Ivan S. Chumakov ◽  
Sergey G. Filinkov ◽  
Dmitry M. Chukin ◽  
Evgeny N. Ishmetyev
Keyword(s):  
Continuous Monitoring ◽  
Drilling Fluid ◽  
Point Of View ◽  
Complete Analysis ◽  
Drilling Fluids ◽  
Automatic Mode ◽  
Design Values ◽  
Drilling Rigs ◽  
Almost All ◽  
Fluid Parameters

Background. The article provides an overview of existing complexes (units) for continuous monitoring of drilling fluid parameters in automatic mode. Aim. To justify the need to develop a complex (module) that will allow combining existing technologies and making a step forward in the field of process automation in terms of monitoring the parameters of drilling fluids. Materials and methods. In the current realities of well construction, the control of drilling fluid parameters on almost all drilling rigs operating on the territory of Russia (possibly with the exception of a few off shore projects) is carried out by the work of a solution engineer, usually a representative of a service company. The analysis of the parameters, depending on the number of personnel, the speed of penetration, the complexity or importance of the well, can be carried out from 2 to 6 times a day [1, 2]. This means a complete analysis, rather than monitoring the density and conditional viscosity, which can be measured by a representative of the drilling crew, for rapid response, and with greater frequency. Due to such a low measurement discreteness, there is a high probability of a significant deviation of the drilling fluid parameters from the design values. As a result, the probability of various complications, both geological and technological, increase significantly. Results. During the analysis of information from open sources, the most promising complexes (modules) from the point of view of application in the current conditions were identified, their positive and negative sides were evaluated. As a result of the conducted review of open sources, the most promising complexes (modules) in terms of application in the current conditions are identified, the positive and negative sides of the systems under consideration are displayed, and the need to develop a complex (module) that will combine all the best that is available today and make a qualitative step forward in the field of “peopleless” technologies used during drilling wells in terms of monitoring the parameters of drilling fluids is justified. Conclusions. The necessity of developing a complex (module) for automating processes in terms of monitoring the parameters of drilling fluids is justified.

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