Fixpoint semantics and optimization of recursive Datalog programs with aggregates

AbstractA very desirable Datalog extension investigated by many researchers in the last 30 years consists in allowing the use of the basic SQL aggregates min, max, count and sum in recursive rules. In this paper, we propose a simple comprehensive solution that extends the declarative least-fixpoint semantics of Horn Clauses, along with the optimization techniques used in the bottom-up implementation approach adopted by many Datalog systems. We start by identifying a large class of programs of great practical interest in which the use of min or max in recursive rules does not compromise the declarative fixpoint semantics of the programs using those rules. Then, we revisit the monotonic versions of count and sum aggregates proposed by Mazuran et al. (2013b, The VLDB Journal 22, 4, 471–493) and named, respectively, mcount and msum. Since mcount, and also msum on positive numbers, are monotonic in the lattice of set-containment, they preserve the fixpoint semantics of Horn Clauses. However, in many applications of practical interest, their use can lead to inefficiencies, that can be eliminated by combining them with max, whereby mcount and msum become the standard count and sum. Therefore, the semantics and optimization techniques of Datalog are extended to recursive programs with min, max, count and sum, making possible the advanced applications of superior performance and scalability demonstrated by BigDatalog (Shkapsky et al. 2016. In SIGMOD. ACM, 1135–1149) and Datalog-MC (Yang et al. 2017. The VLDB Journal 26, 2, 229–248).

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Optimal Fractional PID Controller for Buck Converter Using Cohort Intelligent Algorithm

Applied System Innovation ◽

10.3390/asi4030050 ◽

2021 ◽

Vol 4 (3) ◽

pp. 50

Author(s):

Preeti Warrier ◽

Pritesh Shah

Keyword(s):

Fractional Order ◽

Pid Controller ◽

Power Converters ◽

Buck Converter ◽

Optimization Techniques ◽

Superior Performance ◽

Computational Time ◽

Optimization Approach ◽

Response Characteristics ◽

Fractional Order Controller

The control of power converters is difficult due to their non-linear nature and, hence, the quest for smart and efficient controllers is continuous and ongoing. Fractional-order controllers have demonstrated superior performance in power electronic systems in recent years. However, it is a challenge to attain optimal parameters of the fractional-order controller for such types of systems. This article describes the optimal design of a fractional order PID (FOPID) controller for a buck converter using the cohort intelligence (CI) optimization approach. The CI is an artificial intelligence-based socio-inspired meta-heuristic algorithm, which has been inspired by the behavior of a group of candidates called a cohort. The FOPID controller parameters are designed for the minimization of various performance indices, with more emphasis on the integral squared error (ISE) performance index. The FOPID controller shows faster transient and dynamic response characteristics in comparison to the conventional PID controller. Comparison of the proposed method with different optimization techniques like the GA, PSO, ABC, and SA shows good results in lesser computational time. Hence the CI method can be effectively used for the optimal tuning of FOPID controllers, as it gives comparable results to other optimization algorithms at a much faster rate. Such controllers can be optimized for multiple objectives and used in the control of various power converters giving rise to more efficient systems catering to the Industry 4.0 standards.

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A Survey on Dragonfly Algorithm and its Applications in Engineering

10.36227/techrxiv.11811768.v2 ◽

2020 ◽

Author(s):

Chnoor M. Rahman ◽

Tarik A. Rashid

Keyword(s):

Review Paper ◽

Optimization Problems ◽

Optimization Techniques ◽

Superior Performance ◽

Test Functions ◽

Dragonfly Algorithm ◽

Engineering Problems ◽

Complex Optimization ◽

Metaheuristic Techniques ◽

Benchmark Test Functions

Dragonfly algorithm developed in 2016. It is one of the algorithms used by the researchers to optimize an extensive series of uses and applications in various areas. At times, it offers superior performance compared to the most well-known optimization techniques. However, this algorithm faces several difficulties when it is utilized to enhance complex optimization problems. This work addressed the robustness of the method to solve real-world optimization issues, and its deficiency to improve complex optimization problems. This review paper shows a comprehensive investigation of the dragonfly algorithm in the engineering area. First, an overview of the algorithm is discussed. Besides, we also examine the modifications of the algorithm. The merged forms of this algorithm with different techniques and the modifications that have been done to make the algorithm perform better are addressed. Additionally, a survey on applications in the engineering area that used the dragonfly algorithm is offered. A comparison is made between the algorithm and other metaheuristic techniques to show its ability to enhance various problems. The outcomes of the algorithm from the works that utilized the dragonfly algorithm previously and the outcomes of the benchmark test functions proved that in comparison with some techniques, the dragonfly algorithm owns an excellent performance, especially for small to intermediate applications. Moreover, the congestion facts of the technique and some future works are presented. The authors conducted this research to help other researchers who want to study the algorithm and utilize it to optimize engineering problems.

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A MODEL HIERARCHY FOR IONOSPHERIC PLASMA MODELING

Mathematical Models and Methods in Applied Sciences ◽

10.1142/s0218202504003283 ◽

2004 ◽

Vol 14 (03) ◽

pp. 393-415 ◽

Cited By ~ 45

Author(s):

CHRISTOPHE BESSE ◽

PIERRE DEGOND ◽

FABRICE DELUZET ◽

JEAN CLAUDEL ◽

GÉRARD GALLICE ◽

...

Keyword(s):

Magnetic Field ◽

Plasma Density ◽

Maxwell Equations ◽

Ionospheric Plasma ◽

Practical Interest ◽

Plasma Modeling ◽

Model Hierarchy ◽

Great Practical Interest ◽

Two Fluid ◽

Insight Into

This paper deals with the modeling of the ionospheric plasma. Starting from the two-fluid Euler–Maxwell equations, we present two hierarchies of models. The MHD hierarchy deals with large plasma density situations while the dynamo hierarchy is adapted to lower density situations. Most of the models encompassed by the dynamo hierarchy are classical ones, but we shall give a unified presentation of them which brings a new insight into their interrelations. By contrast, the MHD hierarchy involves a new (at least to the authors) model, the massless-MHD model. This is a diffusion system for the density and magnetic field which could be of great practical interest. Both hierarchies terminate with the "classical" Striation model, which we shall investigate in detail.

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Sticky Thermals: Evidence for a Dominant Balance between Buoyancy and Drag in Cloud Updrafts

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-15-0042.1 ◽

2015 ◽

Vol 72 (8) ◽

pp. 2890-2901 ◽

Cited By ~ 51

Author(s):

David M. Romps ◽

Alexander B. Charn

Keyword(s):

Large Eddy Simulation ◽

Practical Interest ◽

Momentum Equation ◽

Severe Weather ◽

Convective Clouds ◽

Eddy Simulation ◽

Large Eddy ◽

Great Practical Interest ◽

Natural Boundaries ◽

Drag Law

Abstract The vertical velocities of convective clouds are of great practical interest because of their influence on many phenomena, including severe weather and stratospheric moistening. However, the magnitudes of forces giving rise to these vertical velocities are poorly understood, and the dominant balance is in dispute. Here, an algorithm is used to extract thousands of cloud thermals from a large-eddy simulation of deep and tropical maritime convection. Using a streamfunction to define natural boundaries for these thermals, the dominant balance in the vertical momentum equation is revealed. Cloud thermals rise with a nearly constant speed determined by their buoyancy and the standard drag law with a drag coefficient of 0.6. Contrary to suggestions that cloud thermals might be slippery, with a dominant balance between buoyancy and acceleration, cloud thermals are found here to be sticky, with a dominant balance between buoyancy and drag.

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About injuries with a chemical (ink) pencil

Kazan medical journal ◽

10.17816/kazmj57667 ◽

1930 ◽

Vol 26 (8) ◽

pp. 841-843

Author(s):

S. I. Rizvash

Keyword(s):

Human Tissue ◽

Practical Interest ◽

Russian Literature ◽

Medical Institutions ◽

Great Practical Interest ◽

Treatment Of Wounds ◽

Type Of Injury

In Russian literature, very little attention has been paid to this type of injury. I managed to find only 2 articles in which this issue is treated. In the manuals on general and private surgery, both translated and original, there is no indication of the action of aniline pencils on human tissue. Nothing is said about this even in the largest Russian monographs on the treatment of wounds (Trinkler, Petrov). Meanwhile, the injuries caused by a chemical pencil, due to their peculiar course and often even a difficult outcome, are undoubtedly of great practical interest. This prompts me to report two cases of such an injury, which I observed in different medical institutions at almost the same time.

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NESTED GUARDED HORN CLAUSES

International Journal of Foundations of Computer Science ◽

10.1142/s0129054190000187 ◽

1990 ◽

Vol 01 (03) ◽

pp. 249-263 ◽

Cited By ~ 4

Author(s):

MORENO FALASCHI ◽

MAURIZIO GABBRIELLI ◽

GIORGIO LEVI ◽

MASAKI MURAKAMI

Keyword(s):

Logic Programming ◽

Operational Semantics ◽

Horn Clauses ◽

Fixpoint Semantics ◽

New Feature ◽

Definition Of

This paper defines a new concurrent logic language, Nested Guarded Horn Clauses (NGHC). The main new feature of the language is its concept of guard. In fact, an NGHC clause has several layers of (standard) guards. This syntactic innovation allows the definition of a complete (i.e. always applicable) set of unfolding rules and therefore of an unfolding semantics which is equivalent, with respect to the success set, to the operational semantics. A fixpoint semantics is also defined in the classic logic programming style and is proved equivalent to the unfolding one. Since it is possible to embed Flat GHC into NGHC, our method can be used to give a fixpoint semantics to FGHC as well.

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Evaluation of bond strength of cross-laminated LSL specimens under short-span bending

Holzforschung ◽

10.1515/hf-2018-0156 ◽

2019 ◽

Vol 73 (8) ◽

pp. 789-795

Author(s):

Meng Gong ◽

Ling Li ◽

Ying-Hei Chui

Keyword(s):

Bond Strength ◽

Test Procedure ◽

Practical Interest ◽

Adhesive Bond ◽

Bond Quality ◽

Block Shear ◽

The Face ◽

Great Practical Interest ◽

Short Span ◽

Mass Timber

AbstractMass timber panels (MTPs) have a great potential in the construction of mid- and high-rise buildings. Evaluation of the face-bond strength of MTPs is of great practical interest for this kind of products. This study aimed at developing an appropriate test procedure for evaluating the adhesive bond strength of cross-laminated laminated strand lumber (CL-LSL). Three-point short-span bending tests were conducted on two-layer asymmetric CL-LSL specimens (2LasymCL-LSL), which were adhesively bonded by two-component resins of the type polyurethane (PUR) or polyvinyl acetate (PVAc). For comparison, block shear specimens were tested as well. It was found that the 2LasymCL-LSL assembly was better suitable under the short-span bending for differentiating between good and poor bond quality of MTPs.

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EXPERIMENTAL STUDY OF THE CONDITIONS OF SPRAYING LIQUIDS WITH THE AIR FLOW

AGRICULTURAL ENGINEERING ◽

10.26897/2687-1149-2021-6-32-37 ◽

2021 ◽

pp. 32-37

Author(s):

NATALYA G. KOZHEVNIKOVA ◽

Keyword(s):

Dynamic Pressure ◽

Practical Interest ◽

Effective Area ◽

Measurement Point ◽

Factors Affecting ◽

Pests And Diseases ◽

Advantages And Disadvantages ◽

Dynamic Pressure Measurement ◽

Additional Resistance ◽

Great Practical Interest

The processes of air movement in various types of air ducts are of great practical interest in terms of designing, manufacturing, and installing spraying devices used in agricultural production to create artificial fog with fi ne sprinkling and treat crops from pests and diseases. The authors analyze the existing methods of liquid spraying and reveal their main advantages and disadvantages. Under special attention is the pneumatic method. The study found that this method is used to spray contaminated liquids and the spray quality insignificantly depends on the liquid flow rate. It was revealed that one of the main factors affecting the quality indicators of spraying devices is the dynamic pressure of the gas medium acting on the liquid during its spraying. The research has determined that the dynamic pressure value of the airflow during the liquid movement in a horizontal duct depends on three factors: the presence of additional resistance, estimated by the value of the effective area duct, the position of the point at which the pressure was measured relative to the duct axis and the distance between the measurement point and the airflow source. The experimental data were tested for reproducibility using the Cochran criterion at the 5% signifi cancelevel, which proved the process reproducibility. The research has shown that the presence of additional resistance in the duct and the position of the dynamic pressure measurement point relative to the axis of the duct have the same effect on its value. The dynamic pressure of the airflow is primarily dependent on the remoteness of the measurement point from its source.

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Co-crystals and inclusion compounds of leucyl-containing dipeptides

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314089943 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1005-C1005

Author(s):

Melissa Ignacio ◽

Aaron Smith ◽

Dmitriy Soldatov

Keyword(s):

Organic Synthesis ◽

Interlayer Space ◽

Food Additives ◽

Practical Interest ◽

Van Der Waals Interactions ◽

Bioactive Molecules ◽

Short Peptides ◽

Phase 3 ◽

Layered Architecture ◽

Great Practical Interest

Short peptides are ecologically friendly and non-toxic molecules, so they can be safely utilized in green chemistry processes or incorporated in pharmaceuticals and food additives. It has been shown that some dipeptides can form crystals that incorporate other molecules through intermolecular hydrogen bonding and van der Waals interactions[1]. The utilization of such dipeptides for solid state organic synthesis or storage and stabilization of bioactive molecules would be of great practical interest, but the principles that define the successful combinations are not clear. In order to identify what factors lead to complementary pairs of a dipeptide and a second component, a series of leucine-containing dipeptides was screened against 40 organic solvents and solids. Direct or solvent-assisted grinding was used followed by PXRD analysis. It was found that each dipeptide was able to form new phases with some of the utilized reactive and bioactive molecules. The Figure illustrates three experimental powder patterns in the 5-35 2θ degree range. The dipeptide leucyl-valine (1) and the second component 5-acetylsalicylamide (2) combine to form a new crystalline phase (3). After screening was complete, a series of crystallizations was performed and several crystals comprised of both a dipeptide and another molecule have been isolated and studied. A number of structural motifs were observed, although a layered architecture with the second component included in the interlayer space prevailed.

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NUMERICAL INVESTIGATION OF BREAKING IRREGULAR WAVES OVER A SUBMERGED BAR WITH CFD

Coastal Engineering Proceedings ◽

10.9753/icce.v36.waves.43 ◽

2018 ◽

pp. 43

Author(s):

Ankit Aggarwal ◽

Mayilvahanan Alagan Chella ◽

Arun Kamath ◽

Hans Bihs

Keyword(s):

Spectral Characteristics ◽

Wave Spectrum ◽

Practical Interest ◽

Irregular Waves ◽

Regular Waves ◽

Spectrum Change ◽

Individual Wave ◽

Great Practical Interest ◽

Submerged Bar ◽

The Individual

The study of breaking irregular waves is of great practical interest, because of the waves found in the nature. Regular waves are seldom found in the field. Irregular waves can be viewed as the superposition of a number of regular waves (wave components) with the different frequencies and the amplitudes. The breaking process for irregular waves is more complex as compared to breaking regular waves. The energy transfer between the individual wave components of different frequencies also takes place during the breaking process. Due to this, the spectral characteristics of the incident wave spectrum change during the breaking process. The main purpose of the study is to investigate the hydrodynamics during the interaction of breaking irregular waves with a submerged bar.

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