scholarly journals THE MOBILE SYSTEM REDUCTION FOR THE VIBRATION CONTROL IMPLEMENTATION

2019 ◽  
pp. 16-24
Author(s):  
V. V. Lopatin
Keyword(s):  
Oil And Gas ◽  
Random Noise ◽  
Decisive Role ◽  
Mathematical Methods ◽  
National Importance ◽  
System Reduction ◽  
Input And Output ◽  
Measurement Results ◽  
Almost All ◽  
The Given

Since the mining and oil and gas industries play a decisive role in the Ukrainian economy, the adequacy and proper assessment of the accuracy of the monitoring is of great national importance. A mathematical model for the measurement of MSCs is constructed, which determines the sequence of mathematical operations that must be performed to obtain the quantitative characteristics of the objects of control. If there is a function that is a solution and that describes the object of the MSC, then it is a reduction to the ideal MSC. The solution of the problem of reduction (synthesis) MSC is realized by the choice of design and is provided with such a connection between the signals at its input and output MSC, which leads to the best results. This formulation of the problem of reducing the MSC has several disadvantages. The MSC measurement result is always influenced by a number of minor factors. Their effect leads to the fact that the measured value of a certain value is different from the value predicted by the model of measurement of the ISC on the noise (experiment error), which is random. The noise level of MSCs has a significant effect on the result of mathematical processing, and the less the noise, the better the result of the reduction of MSCs. Previously, the task of instrumentation was to create an MSC that provides the least distortion of the measurement results, while using mathematical methods to reduce instrumentation the task of reducing instrumentation noise is MSC. The given  solution is realized by the choice of design and is provided with such a connection between the input and output signals, which leads to a decrease in the level of random noise MSC. The description of MSC enhancement has the instability of the solution of the equation with respect to the initial data errors, which is a property of almost all integral equations and does not depend on the method of their solution. The proposed mathematical method of reduction of the mobile control system (MSC) as one of the variants of regularization of the incorrectly set problem arose and was further developed under the influence of the ideas of academician AN Tikhonov and Professor Yu.P. Pytiev .  The author suggests taking a different look at the control tasks and the accuracy of assessing the accuracy of MCSs by reducing the level of random noise. The author proposed the implementation of the MCS by choosing a design and providing such a connection between the signal at its input and output, which leads to the best results in solving reduction problems. The author proposed an adaptable model of MCSs using modern ideas and mathematical methods.

Deskripsi Kesulitan Belajar Siswa Berdasarkan Karakteristik Lerner dalam Menyelesaikan Soal Geometri

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Nazom Murio ◽  
Roseli Theis
Keyword(s):  
Qualitative Research ◽  
Visual Perception ◽  
Learning Difficulties ◽  
Research Subjects ◽  
Visual Objects ◽  
Almost All ◽  
Personality Classification ◽  
The Given ◽  
Classification Test ◽  
Descriptive Qualitative

Geometri adalah bagian matematika yang sangat dekat dari siswa, karena hampir semua objek visual yang ada di sekitar siswa adalah objek geometri, tetapi tidak semua siswa menyukai pembelajaran yang menyertakan gambar, sehingga memungkinkan siswa mengalami kesulitan dalam belajar geometri. Tujuan dari penelitian ini adalah untuk menggambarkan kesulitan belajar siswa berdasarkan karakteristik Lerner dalam menyelesaikan pertanyaan geometri. Jenis penelitian ini adalah penelitian deskriptif kualitatif. Subjek penelitian adalah siswa dengan kepribadian wali yang mengalami kesulitan belajar di kelas IX A SMP N 30 Muaro Jambi. Instrumen yang digunakan dalam penelitian ini adalah penulis sendiri, lembar tes klasifikasi kepribadian, lembar tes kesulitan belajar, dan pedoman wawancara. Hasil penelitian menunjukkan siswa dengan kepribadian wali yang mengalami kesulitan belajar, 100% mengalami kelainan persepsi visual, di mana siswa mengalami kesulitan dalam menentukan seperti apa bangun datar pada masalah tersebut. 60% mengalami kesulitan mengenali dan memahami simbol, di mana siswa melihat simbol "//" sebagai simbol untuk kesesuaian. Serta 40% mengalami kesulitan dalam bahasa dan membaca, di mana siswa kesulitan dalam memahami pertanyaan yang diberikan.   Geometry is a very close mathematical part of the student, because almost all visual objects that exist around the students are objects of geometry, but not all students like learning that includes images, thus allowing students to have difficulty in learning geometry. The purpose of this research is to describe students' learning difficulties based on Lerner's characteristic in solving the geometry question. This type of research is descriptive qualitative research. Research subjects were students with guardian personality who had difficulty studying in class IX A SMP N 30 Muaro Jambi. Instruments used in this study are the authors themselves, personality classification test sheets, learning difficulties test sheets, and interview guidelines. The results showed students with guardian personality who experienced learning difficulties, 100% experienced visual perception abnormalities, where students have difficulty in determining what kind of flat wake on the matter. 60% have difficulty recognizing and understanding symbols, where students see the symbol "//" as a symbol for conformity. As well as 40% have difficulty in language and reading, where students difficulty in understanding the given question.

scholarly journals Application of isometric transformation and robust estimation to compare the measurement results of steel pipe spools

2020 ◽  
Vol 12 (1) ◽  
pp. 804-812
Author(s):  
Świętoń Tomasz ◽  
Kadaj Roman ◽  
Oleniacz Grzegorz ◽  
Skrzypczak Izabela
Keyword(s):  
Robust Estimation ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Transformation Process ◽  
Precise Determination ◽  
Construction Stage ◽  
Gas Industry ◽  
Design Engineers ◽  
Isometric Transformation ◽  
Measurement Results

AbstractProduction of prefabricated pipe spools for the needs of the oil and gas industry requires precise determination of their shape and dimensions. The crucial moment of production is to measure the spool being built, compare it with the design and define the geometry corrections that should be applied at the construction stage. At present, the comparison of spools is usually done in a manual manner in a CAD program or other software dedicated for this purpose and is implemented by combining variously defined translations and rotations. This approach is time-consuming and the results strongly depend on the survey engineer’s experience. In this article, a method of comparing the shape of two spools, based on isometric transformation and robust estimation, has been proposed. This method can be used to automate the comparison process. In standard approach, applied by both design engineers and assemblers, spools are described by a set of coordinates and, in the case of flanges, by sets of appropriately defined angular values. A method of flange description suitable for use in the isometric transformation process has been proposed, and potential problems that may appear at the implementation stage of the algorithm have been discussed. The proposed method makes it possible to determine the elements of a spool that do not fit into the design project in a way that allows minimizing the number of corrections at the construction stage.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

scholarly journals Optimal solutions of multiplier DEA models

2021 ◽  
Author(s):  
Victor V. Podinovski ◽  
Tatiana Bouzdine-Chameeva
Keyword(s):  
Returns To Scale ◽  
Scale Production ◽  
Optimal Solutions ◽  
Optimal Input ◽  
Input And Output ◽  
Decision Making Unit ◽  
Dea Models ◽  
Constraint Structure ◽  
Conventional Models ◽  
Almost All

AbstractConventional models of data envelopment analysis (DEA) are based on the constant and variable returns-to-scale production technologies. Any optimal input and output weights of the multiplier DEA models based on these technologies are interpreted as being the most favorable for the decision making unit (DMU) under the assessment when the latter is benchmarked against the set of all observed DMUs. In this paper we consider a very large class of DEA models based on arbitrary polyhedral technologies, which includes almost all known convex DEA models. We highlight the fact that the conventional interpretation of the optimal input and output weights in such models is generally incorrect, which raises a question about the meaning of multiplier models. We address this question and prove that the optimal solutions of such models show the DMU under the assessment in the best light in comparison to the entire technology, but not necessarily in comparison to the set of observed DMUs. This result allows a clear and meaningful interpretation of the optimal solutions of multiplier models, including known models with a complex constraint structure whose interpretation has been problematic and left unaddressed in the existing literature.

Be Careful, if You Learn Geography for 8th Grade with „Ucha.se“

2021 ◽  
Vol 30 (1) ◽  
pp. 37-53
Author(s):  
Ivan Drenovski ◽  
Keyword(s):  
Test Items ◽  
Educational Site ◽  
8Th Grade ◽  
Basic Concepts ◽  
Almost All ◽  
The Given

The article analyses the content of the video lessons and corresponding to them test items in Geography and Economics for 8 th grade, available for a fee, on the educational site "Ucha.se". The studied curriculum is related to the introduction of basic concepts and explanations of key processes studied by geology, geophysics, astronomy, geochemistry, geomorphology, meteorology, climatology, hydrology, biology and other sciences. There are serious lapses in the scientific reliability and correctness of the given statements in almost all lessons. Examples of factual errors, incorrectly asked questions, inaccurate images and pseudo-scientific simplifications are pointed.

Subsea Cable Stability on Rocky Seabeds: Comparison of Field Observations Against Conventional and Novel Design Methods

2018 ◽  
Author(s):  
Terry Griffiths ◽  
Scott Draper ◽  
Liang Cheng ◽  
Feifei Tong ◽  
Antonino Fogliani ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Power Transmission ◽  
Small Diameter ◽  
Oil And Gas Industry ◽  
Operational Reliability ◽  
Design Methods ◽  
Gas Industry ◽  
Integrity Management ◽  
Tidal Stream ◽  
Almost All

As offshore renewable energy projects progress from concept demonstration to commercial-scale developments there is a need for improved approaches beyond conventional cable engineering design methods that have evolved from larger diameter pipelines for the oil and gas industry. New approaches are needed to capture the relevant physics for small diameter cables on rocky seabeds to reduce the costs and risks of power transmission and increase operational reliability. This paper reports on subsea cables that MeyGen installed for Phase 1a of the Pentland Firth Inner Sound tidal stream energy project. These cables are located on rocky seabeds in an area where severe metocean conditions occur. ROV field observation of these cables shows them to be stable on the seabed with little or no movement occurring over almost all of the cable routes, despite conventional engineering methods predicting significant dynamic movement. We cite recent research undertaken by the University of Western Australia (UWA) to more accurately assess the hydrodynamic forces and geotechnical interaction of cables on rocky seabeds. We quantify the conformity between the cables and the undulating rocky seabed, and the distributions of cable-seabed contact and spanning via simulations of the centimetric-scale seabed bathymetry. This analysis leads to calculated profiles of lift, drag and seabed friction along the cable, which show that all of these load and reaction components are modelled in an over-conservative way by conventional pipeline engineering techniques. Overall, our analysis highlights that current cable stability design can be unnecessarily conservative on rocky seabeds. Our work foreshadows a new design approach that offers more efficient cable design to reduce project capex and enhance through-life integrity management.

scholarly journals Cryptosystem using double vertex graph

2020 ◽  
Vol 13 (44) ◽  
pp. 4483-4489
Author(s):  
C Beaula ◽  
Keyword(s):  
Graph Theory ◽  
Secure Communication ◽  
System Method ◽  
Encryption And Decryption ◽  
Vertex Graph ◽  
Private And Public ◽  
Almost All ◽  
Encryption Method ◽  
The Given ◽  
Edge Labeling

Background/Objective: The Coronavirus Covid-19 has affected almost all the countries and millions of people got infected and more deaths have been reported everywhere. The uncertainty and fear created by the pandemic can be used by hackers to steal the data from both private and public systems. Hence, there is an urgent need to improve the security of the systems. This can be done only by building a strong cryptosystem. So many researchers started embedding different topics of mathematics like algebra, number theory, and so on in cryptography to keep the system, safe and secure. In this study, a cryptosystem using graph theory has been attempted, to strengthen the security of the system. Method: A new graph is constructed from the given graph, known as a double vertex graph. The edge labeling of this double vertex graph is used in encryption and decryption. Findings: A new cryptosystem using the amalgamation of the path, its double vertex graph and edge labeling has been proposed. From the double vertex graph of a path, we have given a method to find the original path. To hack such an encrypted key, the knowledge of graph theory is important, which makes the system stronger. Applications:The one-word encryption method will be useful in every security system that needs a password for secure communication or storage or authentication. Keywords: Double vertex graphs; path; adjacency matrix; encryption; cryptography

scholarly journals ECONOMIC AND LEGAL ASPECT OF THE NEGATIVE IMPACT OF OIL AND GAS WELLS ON THE ENVIRONMENT

2020 ◽  
pp. 65-70
Author(s):  
E. Yu. Kamchatova ◽  
A. V. Sedova
Keyword(s):  
Oil And Gas ◽  
Negative Impact ◽  
Legal Aspect ◽  
Environmental Safety ◽  
Legal Regulation ◽  
Existing Problems ◽  
Domestic Legislation ◽  
Abandoned Wells ◽  
Negative Impacts ◽  
Almost All

The negative impact on the environment is carried out from almost all oil and gas facilities. One of such objects are wells of any purpose. The causes of negative impacts on the environment from plugged and abandoned wells were identified in the course of the study. Existing methods and technologies of well liquidation and conservation have been analyzed in the article. Existing problems in the legal regulation of the issue of environmental safety of abandoned wells have been investigated. The result of comparison of the international and domestic legislation on this problem has been presented.

scholarly journals The Delay Measurement and Analysis of Unreachable Hosts of Internet

2022 ◽  
Author(s):  
Ali Gezer
Keyword(s):  
Trip Time ◽  
Internet Control ◽  
Delay Measurement ◽  
Measurement Results ◽  
Measurement And Analysis ◽  
Control Message ◽  
Almost All ◽  
Random Behaviour ◽  
Shed Light

Delay related metrics are significant quality of service criteria for the performance evaluation of networks. Almost all delay related measurement and analysis studies take into consideration the reachable sources of Internet. However, unreachable sources might also shed light upon some problems such as worm propagation. In this study, we carry out a delay measurement study of unreachable destinations and analyse the delay dynamics of unreachable nodes. 2. Internet Control Message Protocol (ICMP) destination unreachable Internet Control Message Protocol-Destination Unreachable (ICMP T3) packets are considered for the delay measurement according to their code types which shows network un reach ability, host un reach ability, port un reach ability, etc. Measurement results show that unreachable sources exhibit totally different delay behaviour compared to reachable IP hosts. A significant part of the unreachable hosts experiences extra 3 seconds Round Trip Time (RTT) delay compared to accessible hosts mostly due to host un reach ability. It is also seen that, approximately 79% of destination un reach ability causes from host un reach ability. Obtained Hurst parameter estimation results reveal that unreachable host RTTs show lower Hurst degree compared to reachable hosts which is approximately a random behaviour. Unreachable sources exhibit totally different distributional characteristic compared to accessible ones which is best fitted with Phased Bi-Exponential distribution.

A Context-Aware Model of Trust for Facilitating Secure Ad Hoc Collaborations

2010 ◽  
pp. 250-281 ◽  
Author(s):  
Indrajit Ray ◽  
Indrakshi Ray ◽  
Sudip Chakraborty
Keyword(s):  
Incomplete Information ◽  
Ad Hoc ◽  
Sensitive Information ◽  
Trust Value ◽  
Trust Relationships ◽  
The Face ◽  
Trust Models ◽  
Almost All ◽  
Ad Hoc Collaborations ◽  
The Given

Ad hoc collaborations often necessitate impromptu sharing of sensitive information or resources between member organizations. Each member of resulting collaboration needs to carefully assess and tradeoff the requirements of protecting its own sensitive information against the requirements of sharing some or all of them. The challenge is that no policies have been previously arrived at for such secure sharing (since the collaboration has been formed in an ad hoc manner). Thus, it needs to be done based on an evaluation of the trustworthiness of the recipient of the information or resources. In this chapter, the authors discuss some previously proposed trust models to determine if they can be effectively used to compute trustworthiness for such sharing purposes in ad hoc collaborations. Unfortunately, none of these models appear to be completely satisfactory. Almost all of them fail to satisfy one or more of the following requirements: (i) well defined techniques and procedures to evaluate and/or measure trust relationships, (ii) techniques to compare and compose trust values which are needed in the formation of collaborations, and (iii) techniques to evaluate trust in the face of incomplete information. This prompts the authors to propose a new vector (we use the term “vector” loosely; vector in this work means a tuple) model of trust that is suitable for reasoning about the trustworthiness of systems built from the integration of multiple subsystems, such as ad hoc collaborations. They identify three parameters on which trust depends and formulate how to evaluate trust relationships. The trust relationship between a truster and a trustee is associated with a context and depends on the experience, knowledge, and recommendation that the truster has with respect to the trustee in the given context. The authors show how their model can measure trust in a given context. Sometimes enough information is not available about a given context to calculate the trust value. Towards this end the authors show how the relationships between different contexts can be captured using a context graph. Formalizing the relationships between contexts allows us to extrapolate values from related contexts to approximate a trust value of an entity even when all the information needed to calculate the trust value is not available. Finally, the authors develop formalisms to compare two trust relationships and to compose two or more of the same – features that are invaluable in ad hoc collaborations.

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