scholarly journals A Comparative Study of Services Placement Algorithms in Future Networks: دراسة مقارنة لخوارزميّات توضيع الخدمات في الشّبكات المستقبليّة

2021 ◽  
Vol 5 (5) ◽  
pp. 64-51
Author(s):  
Manar Yacoub Al-Jabr, Ali Diab, Jomana diab Manar Yacoub Al-Jabr, Ali Diab, Jomana diab
Keyword(s):  
Optimal Placement ◽  
Management Service ◽  
Placement Problem ◽  
Qualitative Comparison ◽  
Comprehensive Knowledge ◽  
Future Networks ◽  
Placement Algorithms ◽  
Placement Algorithm ◽  
The Cost ◽  
The Ideal

The study aimed to analyze and compare several algorithms in the context of networks services placement, and then proposed a self-organized dynamic heuristic algorithm adaptable to continually changing network conditions in order to achieve the ideal placement of services replicas in future networks. It is known that future networks demand a high degree of self-organization to keep pace with ongoing changes while maintaining performance optimized. One of the important challenges in this context is the services placement problem. Service placement issue refers to the selection of the most appropriate network node for hosting a service. The ideal placement of services replicas reduces the cost of serving customers, improves connectivity between clients and servers as well as the use of available resources. The study summarized the results of qualitative comparison between several placement algorithms and refers to the most important requirements to be taken into account when implementing the placement algorithm. Generally, each service has its own placement technique, and the action taken by a specific service may affect other services decisions and force them to adapt. There is an urgent need to  a management service for managing services replicas to make the optimal placement decision. This service should work in a distributed manner and does not require comprehensive knowledge about the  network. It is also characterized by its ability to adapt to changing network conditions in terms of load and topology. Other services coordinate with the management service about replicating or migrating actions,  thus services will be offered  at a minimized cost.

scholarly journals Improved Formulation for the Optimization of Wind Turbine Placement in a Wind Farm

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Zong Woo Geem ◽  
Junhee Hong
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Fossil Fuels ◽  
Optimal Placement ◽  
Branch And Bound Method ◽  
Optimal Layout ◽  
Objective Functions ◽  
Placement Problem ◽  
Optimization Formulation ◽  
The Cost

As an alternative to fossil fuels, wind can be considered because it is a renewable and greenhouse gas-free natural resource. When wind power is generated by wind turbines in a wind farm, the optimal placement of turbines is critical because different layouts produce different efficiencies. The objective of the wind turbine placement problem is to maximize the generated power while minimizing the cost in installing the turbines. This study proposes an efficient optimization formulation for the optimal layout of wind turbine placements under the resources (e.g., number of turbines) or budget limit by introducing corresponding constraints. The proposed formulation gave users more conveniences in considering resources and budget bounds. After performing the optimization, results were compared using two different methods (branch and bound method and genetic algorithm) and two different objective functions.

scholarly journals A general-purpose method for Pareto optimal placement of flow rate and concentration sensors in networked systems - With application to wastewater treatment plants

2020 ◽  
Author(s):  
Kris Villez ◽  
Peter A Vanrolleghem ◽  
lluis corominas
Keyword(s):  
Data Quality ◽  
High Speed ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Sensor Placement ◽  
General Purpose ◽  
Optimal Placement ◽  
Pareto Optimal ◽  
Placement Problem ◽  
The Cost

The advent of affordable computing, low-cost sensor hardware, and high-speed and reliable communications have spurred ubiquitous installation of sensors in complex engineered systems. However, ensuring reliable data quality remains a challenge. Exploitation of redundancy among sensor signals can help improving the precision of measured variables, detecting the presence of gross errors, and identifying faulty sensors. The cost of sensor ownership, maintenance efforts in particular, can still be cost-prohibitive however. Maximizing the ability to assess and control data quality while minimizing the cost of ownership thus requires a careful sensor placement. To solve this challenge, we develop a generally applicable method to solve the multi-objective sensor placement problem in systems governed by linear and bilinear balance equations. Importantly, the method computes all Pareto-optimal sensor layouts with conventional computational resources and requires no information about the expected sensor quality.

scholarly journals Dynamic Placement Analysis of Wind Power Generation Units in Distribution Power Systems

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2326 ◽  
Author(s):  
Mohammad Baghayipour ◽  
Amin Hajizadeh ◽  
Amir Shahirinia ◽  
Zhe Chen
Keyword(s):  
Power Systems ◽  
Distribution Network ◽  
Distribution Networks ◽  
Optimal Placement ◽  
Renewable Energy Resources ◽  
Placement Problem ◽  
Distributed Generators ◽  
Time Variations ◽  
Placement Algorithm ◽  
Nodal Voltage

The placement problem of distributed generators (DGs) in distribution networks becomes much more complicated in the case of using the DGs with renewable energy resources. Due to several reasons such as, their intermittent output powers, the interactions between DGs and the rest of the distribution network, and considering other involved uncertainties are very vital. This paper develops a new approach for optimal placement of wind energy based DGs (WDGs) in which all of such influences are carefully handled. The proposed method considers the time variations of dynamic nodal demands, nodal voltage magnitudes, and wind speed in the WDG placement process simultaneously. Thereby, an accurate dynamic model of the active and reactive powers injected by the WDG to the system is employed in which the interactions between the WDG and the distribution network are well regarded. Finally, simulation results are given to show the capability of the proposed approach. As it is demonstrated in the numerical analysis of the radial 33-bus distribution test network, the proposed placement algorithm can efficiently determine the optimal bus for connecting the WDG and is suitable for real applications.

Optimal Placement of FACTS Devices for Voltage Stability Improvement with Economic Consideration Using Firefly Algorithm

2019 ◽  
Vol 14 (1) ◽  
pp. 5-11
Author(s):  
S. Rajasekaran ◽  
S. Muralidharan
Keyword(s):  
Power Systems ◽  
Voltage Stability ◽  
Firefly Algorithm ◽  
Transmission System ◽  
Operating Conditions ◽  
Optimal Placement ◽  
Voltage Collapse ◽  
Facts Devices ◽  
The Cost ◽  
Bus System

Background: Increasing power demand forces the power systems to operate at their maximum operating conditions. This leads the power system into voltage instability and causes voltage collapse. To avoid this problem, FACTS devices have been used in power systems to increase system stability with much reduced economical ratings. To achieve this, the FACTS devices must be placed in exact location. This paper presents Firefly Algorithm (FA) based optimization method to locate these devices of exact rating and least cost in the transmission system. Methods: Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) are the FACTS devices used in the proposed methodology to enhance the voltage stability of power systems. Considering two objectives of enhancing the voltage stability of the transmission system and minimizing the cost of the FACTS devices, the optimal ratings and cost were identified for the devices under consideration using Firefly algorithm as an optimization tool. Also, a model study had been done with four different cases such as normal case, line outage case, generator outage case and overloading case (140%) for IEEE 14,30,57 and 118 bus systems. Results: The optimal locations to install SVC and TCSC in IEEE 14, 30, 57 and 118 bus systems were evaluated with minimal L-indices and cost using the proposed Firefly algorithm. From the results, it could be inferred that the cost of installing TCSC in IEEE bus system is slightly higher than SVC.For showing the superiority of Firefly algorithm, the results were compared with the already published research finding where this problem was solved using Genetic algorithm and Particle Swarm Optimization. It was revealed that the proposed firefly algorithm gives better optimum solution in minimizing the L-index values for IEEE 30 Bus system. Conclusion: The optimal placement, rating and cost of installation of TCSC and SVC in standard IEEE bus systems which enhanced the voltage stability were evaluated in this work. The need of the FACTS devices was also tested during the abnormal cases such as line outage case, generator outage case and overloading case (140%) with the proposed Firefly algorithm. Outputs reveal that the recognized placement of SVC and TCSC reduces the probability of voltage collapse and cost of the devices in the transmission lines. The capability of Firefly algorithm was also ensured by comparing its results with the results of other algorithms.

scholarly journals Analysis of Non-Idealities on CMOS Passive Mixers

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1105
Author(s):  
Antonio D. Martinez-Perez ◽  
Francisco Aznar ◽  
Guillermo Royo ◽  
Santiago Celma
Keyword(s):  
Final Section ◽  
Cmos Technology ◽  
Monte Carlo Analysis ◽  
Image Rejection ◽  
Structure Approach ◽  
Quadrature Scheme ◽  
Current State ◽  
The Cost ◽  
Image Rejection Ratio ◽  
The Ideal

In the current state of the art, WiFi-alike standards require achieving a high Image Rejection Ratio (IRR) while having low power consumption. Thus, quadrature structures based on passive ring mixers offer an attractive and widely used solution, as they can achieve a high IRR while being a passive block. However, it is not easy for the designer to know when a simple quadrature scheme is enough and when they should aim for a double quadrature structure approach, as the latter can improve the performance at the cost of requiring more area and complexity. This study focuses on the IRR, which crucially depends on the symmetry between the I and Q branches. Non-idealities (component mismatches, parasitics, etc.) will degrade the ideal balance by affecting the mixer and/or following/previous stages. This paper analyses the effect of imbalances, providing the constraints for obtaining a 40 dB IRR in the case of a conversion from a one-hundred-megahertz signal to the five-gigahertz range (upconversion) and vice versa (downconversion) for simple and double quadrature schemes. All simulations were carried out with complete device models from 65 nm standard CMOS technology and also a post-layout Monte Carlo analysis was included for mismatch analysis. The final section includes guidelines to help designers choose the most adequate scheme for each case.

High-Efficiency Cut Blasting with Shell Radial Shaped Charge in Laboratory-Scale Blasting

2015 ◽  
Vol 1094 ◽  
pp. 445-450 ◽  
Author(s):  
Wei Chen ◽  
Hong Hao Ma ◽  
Zhao Wu Shen ◽  
De Bao Wang
Keyword(s):  
High Efficiency ◽  
Circular Tube ◽  
Rock Breaking ◽  
Shaped Charge ◽  
Axial Line ◽  
Rock Excavation ◽  
Crack Network ◽  
Utilization Ratio ◽  
The Cost ◽  
The Ideal

Due to the inefficiency problem of the cut blasting in rock excavation and rock breaking, a shell radial shaped charge device was proposed based of the ideal of ‘cutting to slotting’ and it was validated through experiments. For this device, the shell materials are used to be shaped materials and multiple shaped ring is designed on the circular tube. It can not only reduce charge quantity but also raise the utilization ratio of explosive energy. After explosion, multiple radial shaped charge jets can be formed along the axial line in sequence and then the surrounding rock mass would be cracked. The crack network will be formed along with the further extension of the fraction under the action of quasi static loading of detonation gas. The shell radial shaped charge device was tested through the cut blasting model experiment. Experimental results show that the utilization ratio of blasting hole nearly approaches 98% with this device. The blasting efficiency and cyclical footage can be improved effectively and the cost of drifting can also be reduced.

Application of Tabu Search for Optimal Placement and Sizing of Distributed Generation for Loss Reduction

2012 ◽  
Vol 433-440 ◽  
pp. 7190-7194 ◽  
Author(s):  
Nattachote Rugthaicharoencheep ◽  
Thong Lantharthong ◽  
Awiruth Ratreepruk ◽  
Jenwit Ratchatha
Keyword(s):  
Tabu Search ◽  
Distributed Generation ◽  
Distribution System ◽  
Power Loss ◽  
Power Flow ◽  
Search Algorithm ◽  
Optimal Placement ◽  
Loss Reduction ◽  
Placement Problem ◽  
Bus Voltage

This paper presents the optimal and sizing of distributed generation (DG) placement in a radial distribution system for loss reduction. The main emphasis of this paper is to identify proper locations for installing DGs in a distribution system to reduce active power loss and improve bus voltages. Nevertheless, proper placement and sizing of DG units are not straightforward to be identified as a number of their positions and capacities need to be determined. It is therefore proposed in this paper to solve a DG placement problem based on a Tabu search algorithm. The objective function of the problem is to minimize the system loss subject to power flow constraints, bus voltage limits, pre specified number of DGs, and their allowable total installed capacity, and only one distributed generator for one installation position. The effectiveness of the methodology is demonstrated by a practical sized distribution system consisting of 69 bus and 48 load points. The results show that the optimal DG placement and sizing can be identified to give the minimum power loss while respecting all the constraints.

Optimal actuator placement in adaptive optics systems

2021 ◽  
pp. 107754632110324
Author(s):  
Berk Altıner ◽  
Bilal Erol ◽  
Akın Delibaşı
Keyword(s):  
Cost Function ◽  
Adaptive Optics ◽  
Disturbance Attenuation ◽  
Linear Quadratic ◽  
Placement Problem ◽  
Convex Optimization Problem ◽  
Wavefront Aberrations ◽  
The Cost ◽  
Actuator Placement ◽  
Quadratic Cost Function

Adaptive optics systems are powerful tools that are implemented to degrade the effects of wavefront aberrations. In this article, the optimal actuator placement problem is addressed for the improvement of disturbance attenuation capability of adaptive optics systems due to the fact that actuator placement is directly related to the enhancement of system performance. For this purpose, the linear-quadratic cost function is chosen, so that optimized actuator layouts can be specialized according to the type of wavefront aberrations. It is then considered as a convex optimization problem, and the cost function is formulated for the disturbance attenuation case. The success of the presented method is demonstrated by simulation results.

Agile framework for capital projects

2021 ◽  
Vol 61 (2) ◽  
pp. 422
Author(s):  
Polly Mahapatra ◽  
Paris Shahriari
Keyword(s):  
Oil And Gas ◽  
Hybrid Approach ◽  
Oil And Gas Industry ◽  
Quick Response ◽  
Capital Projects ◽  
Gas Industry ◽  
Response To Change ◽  
The Cost ◽  
Early Phases ◽  
The Ideal

Under the increased pressure of rapidly changing market conditions and disrupting technologies, continuous improvements in efficiency become indispensable for all oil and gas operators. Traditional project management principles in the oil and gas industry employ rigid methods of planning and execution that can sometimes hinder adaptability and a quick response to change. Considering the potential that Agile principles can offer as a solution, the challenge, therefore, is to identify the ideal, hybrid, approach that leverages Agile while incorporating the traditional linear workflow necessitated by the oil and gas industry. This paper seeks to assess pre-existing literature in the application of the Agile principles in the oil and gas industry with a focus on Major Capital Projects (MCPs), backed by the successes experienced as a result of specific pilot projects completed at Chevron’s Australian Business Unit. In particular, this paper will focus on how agility has resulted in improvements to the cost, schedule, teaming and cohesion of MCPs in the early phases as well as key learnings form the pilot agility projects.

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