scholarly journals Optimal drill string design for acoustic borehole communication

2021 ◽  
Vol 8 (11) ◽  
pp. 96-103
Author(s):  
Ali H. Alenezi ◽  
Keyword(s):  
Acoustic Telemetry ◽  
Communication Channel ◽  
Channel Model ◽  
Data Transfer ◽  
Small Deviation ◽  
Drill String ◽  
Channel Bandwidth ◽  
Drilling Operations ◽  
Main Components

The acoustic telemetry used the drill string as a communication channel, which allows data transfer without interrupting drilling operations. This technology suffers from stop-bands that reduce the feasible bands for transmission up to 60 percent. The stop bands come due to the structure of the drill string constructed from pipes and tool joints. In this paper, we optimized the design of the drill string main components, which are pipes and tool-joints lengths, with an aim to increase the pass-bands total bandwidth. Using the verified drill string channel model, we proved that, with optimal lengths of pipes and tool joints, we can make the whole drill string channel bandwidth available for transmission. We also investigated the effect of small deviation from the optimal lengths on the channel transmission bands. The results showed that an increase of more than 138 percent in the available transmission bandwidths compared with standard drill string dimensions.

An Enhanced Cloud Security using Quantum Teleportation

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
D. Sowmya ◽  
S. Sivasankaran
Keyword(s):  
Quantum Key Distribution ◽  
Quantum Teleportation ◽  
Quantum Physics ◽  
Communication Channel ◽  
Data Transfer ◽  
Cloud Security ◽  
The Other ◽  
Cloud Environment ◽  
Quantum Bits ◽  
Quantum Parallelism

In the cloud environment, it is difficult to provide security to the monolithic collection of data as it is easily accessed by breaking the algorithms which are based on mathematical computations and on the other hand, it takes much time for uploading and downloading the data. This paper proposes the concept of implementing quantum teleportation i.e., telecommunication + transportation in the cloud environment for the enhancement of cloud security and also to improve speed of data transfer through the quantum repeaters. This technological idea is extracted from the law of quantum physics where the particles say photons can be entangled and encoded to be teleported over large distances. As the transfer of photons called qubits allowed to travel through the optical fiber, it must be polarized and encoded with QKD (Quantum Key Distribution) for the security purpose. Then, for the enhancement of the data transfer speed, qubits are used in which the state of quantum bits can be encoded as 0 and 1 concurrently using the Shors algorithm. Then, the Quantum parallelism will help qubits to travel as fast as possible to reach the destination at a single communication channel which cannot be eavesdropped at any point because, it prevents from creating copies of transmitted quantum key due to the implementation of no-cloning theorem so that the communication parties can only receive the intended data other than the intruders.

Study of stick–slip suppression and robustness to parametric uncertainty in drill strings containing torsional vibration tool using sliding-mode control

2021 ◽  
pp. 146441932110452
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai
Keyword(s):  
Torsional Vibration ◽  
Complex Dynamics ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Drill String ◽  
Lumped Parameter Model ◽  
Drilling Process ◽  
Drill Bit ◽  
Stick Slip ◽  
Drilling Operations

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety of drilling operations. To suppress the stick–slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of the 4-degree of freedom lumped-parameter model. In the design of the model, the tool is approximated by a simple torsional pendulum that brings impact torque to the drill bit. Furthermore, two sliding mode controllers, U1 and U2, are used to suppress stick–slip vibrations while enabling the drill bit to track the desired angular velocity. Aiming at parameter uncertainty and system instability in the drilling operations, a parameter adaptation law is added to the sliding mode controller U2. Finally, the suppression effects of stick–slip and robustness of parametric uncertainty about the two proposed controllers are demonstrated and compared by simulation and field test results. This paper provides a reference for the suppression of stick–slip vibration and the further study of the complex dynamics of the drill string.

Dynamic Drill-string Modeling for Acoustic Telemetry

2022 ◽  
pp. 107043
Author(s):  
Hamid Mostaghimi ◽  
Jediael R. Pagtalunan ◽  
Bryan Moon ◽  
Seonghwan Kim ◽  
Simon S. Park
Keyword(s):  
Acoustic Telemetry ◽  
Drill String

scholarly journals Research on Spatial Channel Model for Vehicle-to-Vehicle Communication Channel in Roadside Scattering Environment

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Xin Chen ◽  
Yong Fang ◽  
Weidong Xiang ◽  
Liang Zhou
Keyword(s):  
Communication Channel ◽  
Channel Model ◽  
Critical Distance ◽  
Traffic Density ◽  
Vehicle Speed ◽  
Angle Of Arrival ◽  
Vehicle To Vehicle ◽  
Proposed Model ◽  
Spatial Channel Model ◽  
The Impact

In this paper, an extension of spatial channel model (SCM) for vehicle-to-vehicle (V2V) communication channel in roadside scattering environment is investigated for the first time theoretically and by simulations. Subsequently, to efficiently describe the roadside scattering environment and reflect the nonstationary properties of V2V channels, the proposed SCM V2V model divides the scattering objects into three categories of clusters according to the location of effective scatterers by introducing critical distance. We derive general expressions for the most important statistical properties of V2V channels, such as channel impulse response, power spectral density, angular power density, autocorrelation function, and Doppler spread of the proposed model. The impact of vehicle speed, traffic density, and angle of departure, angle of arrival, and other statistical performances on the V2V channel model is thoroughly discussed. Numerical simulation results are presented to validate the accuracy and effectiveness of the proposed model.

A COMPREHENSIVE AUTOMATED SOLUTION TO THE PROBLEM OF AIR ENVIRONMENT MONITORING

2021 ◽  
Author(s):  
В.А. ОСАНОВ ◽  
С.М. КОНДРАТЬЕВ ◽  
О.С. КОНЯЕВА
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Communication Channel ◽  
Data Transfer ◽  
Automated System ◽  
Environment Monitoring ◽  
Practical Application ◽  
Air Masses ◽  
System Functioning ◽  
Direction Of Movement ◽  
Software And Hardware

Рассмотрена автоматизированная система мониторинга воздушной среды с использованием технологий беспилотных летательных аппаратов, оснащенных датчиками для выявления вредных веществ. Представлены алгоритм функционирования системы и программно-аппаратная часть решения. Показано, что канал связи на основе методов шифрования обеспечивает безопасную передачу данных с беспилотного аппарата на сервер. Результаты исследования найдут практическое применение в мониторинге уровня загрязнения воздуха в городах. An automated system for monitoring the air environment using technologies of unmanned aerial vehicles equipped with sensors for detecting harmful substances is considered. The algorithm of the system functioning and the software and hardware part of the solution are presented. It is shown that a communication channel based on encryption methods ensures secure data transfer from an unmanned vehicle to a server. The results of the study will find practical application in monitoring the level of air pollution in cities and in predicting the direction of movement of polluting air masses.

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