Nowadays, wireless access networks are already amongst the top power consumers in the ICT (Information and Communication Technology) sector. As it expected that these networks will further expand in the future due to ...
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ISBN:
(纸本)9781509020881
Nowadays, wireless access networks are already amongst the top power consumers in the ICT (Information and Communication Technology) sector. As it expected that these networks will further expand in the future due to the extreme growth in mobile devices and the high bit rate demand of the applications running on these devices, it is important to consider power consumption as a key parameter in the network design phase. In this paper, two optimization algorithms are proposed: a capacity-based heuristic which aims to reduce power consumption by responding to the instantaneous bit rate demand by the user and an evolutionary opposition-based learning algorithm focusing on the joint-optimization of power consumption and geometrical coverage. Applying both algorithms on a realistic suburban case in Ghent, Belgium, show that both algorithms are able to design an LTE-A network consuming only 24% and 29%, respectively, of the power consumed by the reference scenario which is representative for today's networks. The evolutionary algorithm outperforms the capacity-based algorithm by obtaining a 5% lower power consumption, while the capacity-based heuristic has a 2 to 3% higher coverage. Future research in joint-optimization algorithms of energy and network performance is definitely needed.
The sheet beam traveling-wave tube (SBTWT) with staggered double vane (SDV) structure has attracted much attention as a board band and powerful terahertz and millimeter-wave source. In this paper, the velocity taper f...
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ISBN:
(纸本)9781538682883
The sheet beam traveling-wave tube (SBTWT) with staggered double vane (SDV) structure has attracted much attention as a board band and powerful terahertz and millimeter-wave source. In this paper, the velocity taper for SDV structure is optimized with a recently proposed swarm-intelligence (SI) based optimization algorithm named dragonfly algorithm (DA) in order to enhance the beam-wave interaction efficiency in sheet beam TWT. The optimization result of this algorithm is compared with other commonly used algorithms. The taper optimized with DA is verified with CST particle in cell (PIC) simulations. The efficiency of the optimized structure has been greatly increased in both optimization and PIC simulations.
Heat dissipations of servers in datacenter racks are following an ever-increasing trend, breaking the economical heat removal limits of traditional air-based cooling technologies. Currently, an average of 40-45% of th...
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ISBN:
(纸本)9781728124612
Heat dissipations of servers in datacenter racks are following an ever-increasing trend, breaking the economical heat removal limits of traditional air-based cooling technologies. Currently, an average of 40-45% of the total datacenter energy consumption is needed to cool servers, presenting significant challenges to maintain energy efficiencies and also noise levels within US OSHA standards The present paper focuses on the determination of the optimal design of a compact plate heat exchanger (PHE), acting as an overhead refrigerant-to-water condenser of a macro-scale thermosyphon, which dissipates the total heat from a datacenter rack into a cooling loop for waste heat recovery applications (e.g. district heating network). PHEs are already the preferred solution for many industrial and domestic applications (especially small to medium size refrigeration and heat pump systems), since they provide higher heat transfer performance, higher flexibility toward the targeted application and lower pressure drops compared to the conventional tube-in-tube and shell-and-tube heat exchangers. Furthermore, due to the numerous variables involved in the design of PHEs, such as plate number, plate footprint size, geometry of the corrugation pattern (i.e. chevron angle, pressing depth, etc.), an optimization analysis and corresponding simulation tool is auspicious to finding the optimal design of these units to accommodate the targeted heat rates of datacenter racks. Hence, this study proposes a novel optimization process which incorporates a local simulator (an improved version compared to the one presented at ITHERM 2018) for accurately rating and designing PHEs over a wide range of operating conditions, plate geometries and working fluids. The improved simulator uses a local one-dimensional effectiveness-NTU approach, with a local implementation of mass, momentum and energy equations, coupled with newly upgraded methods for condensation heat transfer coefficients and frictional p
The path planning of Unmanned Underwater Vehicle (UUV) is a crucial aspect of their operation in underwater environments, Meta-heuristic algorithms are extensively utilized for addressing UUV path planning problems. T...
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ISBN:
(纸本)9798350352573
The path planning of Unmanned Underwater Vehicle (UUV) is a crucial aspect of their operation in underwater environments, Meta-heuristic algorithms are extensively utilized for addressing UUV path planning problems. To address the limitations of the traditional dung beetle optimization algorithm (DBO), including inadequate convergence speed and precision in two-dimensional UUV path planning, and its propensity for local optima, an improved dung beetle optimization algorithm (IDBO) is introduced which employing a suite of refinement strategies. Furthermore, the solution capability of the IDBO is validated through the CEC2017 test suite and two-dimensional raster maps that replicate actual underwater environments. The simulation results demonstrate the robust problem-solving capacity of the IDBO, applicable to both benchmark functions and real-world scenarios, affirming the efficacy of the enhancement strategies in practical applications.
Immune evolutionary algorithm is proposed based on the evolutionary principle in the immune system. In the algorithm, two new parameters of expansion radius and mutation radius are defined to construct a small neighbo...
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ISBN:
(纸本)0780378652
Immune evolutionary algorithm is proposed based on the evolutionary principle in the immune system. In the algorithm, two new parameters of expansion radius and mutation radius are defined to construct a small neighborhood and a large neighborhood. Then expansion and mutation operations are designed to perform local and global search respectively by using the two neighborhoods, thus, two-level neighborhood search mechanism is realized. The results of multi-modal function optimization show that the algorithm has nice global and local searching performances. The algorithm is employed to design a neuro-fuzzy controller for real-time control of an inverted pendulum. In order to avoid the combinatorial explosion of fuzzy rules due to multivariable inputs, state variable synthesis scheme is suggested to reduce the number of fuzzy rules. Experimental results show that the designed controller can control actual inverted pendulum successfully.
This paper attempts to find an optimization algorithm to reduce number of iterations required for a node to be searched in a MultiCast Tee network. After effectively searching the node, it applies this technique in cl...
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ISBN:
(纸本)9781479976782
This paper attempts to find an optimization algorithm to reduce number of iterations required for a node to be searched in a MultiCast Tee network. After effectively searching the node, it applies this technique in cloud computing, more exactly, cloud information security so that data is safely transferred from one user to another, without any hindrance. The basic idea to incorporate the concept of MultiCast Tree is because it always supports reliable transmission of information, if by any chance, there is a link failure, it does not reduce the availability of resources, nor does it increase any delay in transmission of information, and at the same time minimizes work load. Thus, we can effectively use it in cloud computing, which is nothing but provision of resources to a pool of users through some kind of an interface, for example, Internet. While monitoring the distributed foundation establishment of cloud computing, it becomes extremely important to take into consideration the security of the information provided by users. If we use a vast number of nodes or links, it becomes practically impossible to trace the reliability of transmission, and which might result in important information getting lost. Hence to avoid such a consequence, it becomes necessary to optimize the number of these links, so that it becomes easier to search them in a minimum amount of time. Our main attempt has been to optimize these links and effectively use it in a communication network which has characteristics of a MultiCast Tree incorporated in it. This not only helps in efficient use of cloud computing system, but also ensures users that their data is in safe hands.
The dynamic characteristics of bridge structures, such as the natural frequencies, mode shapes and model damping ratio, are the basis of structural dynamic computation, seismic analysis, vibration control and structur...
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The dynamic characteristics of bridge structures, such as the natural frequencies, mode shapes and model damping ratio, are the basis of structural dynamic computation, seismic analysis, vibration control and structural health condition monitoring. In this paper, a three-dimensional finite-element model is established for a highway bridge over a railway on No.312 National Highway and the ambient test is carried out in site, the dynamic characteristics of the bridge are studied using the finite-element analysis and ambient vibration measurements. Comparison between the theoretical and experimental results shows that the frequency differences of the modes range between 0.44% and 8.77%. If the measurement is more reliable, the finite element model updating is necessary. Thus, a set of design variables is selected based on sensitivity analysis, then the finite element model of the bridge is updated based on optimization algorithm. The results of model updating show that the proposed updating method in this paper is more simple and effective, the updated finite element model can reflect the dynamic characteristics of the bridge better, the analytical results can provide the theoretical basis for damage identification and health condition monitoring of the bridge.
A new structure of hydraulic hybrid vehicle (HHV) with hydraulic transformer (HT) was built and the working principle of the new hydraulic hybrid vehicle was described. According to the operating characteristics of HT...
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ISBN:
(纸本)9783037850398
A new structure of hydraulic hybrid vehicle (HHV) with hydraulic transformer (HT) was built and the working principle of the new hydraulic hybrid vehicle was described. According to the operating characteristics of HT and energy-saving optimization conditions of accumulator used the HHV;Energy-saving optimization control algorithm with various operation conditions in different working conditions of vehicle was established. Then, simulation analysis to control performance of energy-saving algorithm was carried out using PID, Fuzzy Logic Controller (FLC) and Fuzzy-PID control strategy. Results show that Fuzzy-PID controller has a small influence on the parameters of energy-saving optimization algorithm of the hydraulic hybrid vehicle and maximizing energy recovery can be achieved in different energy states by Fuzzy-PID controller.
A finite-element analysis-based optimal design of an electric machine takes considerable time for its objective evaluation and has many local minima. Thus, selecting an appropriate global convergence optimization with...
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A finite-element analysis-based optimal design of an electric machine takes considerable time for its objective evaluation and has many local minima. Thus, selecting an appropriate global convergence optimization with fast convergence speed is necessary in the optimal design of an electric machine. In this paper, a novel global search optimization algorithm, mass ionized particle optimization (MIPO), is newly proposed. The MIPO is the population-based algorithm, which reflects the interactive force between the ionized particles. The global convergence and the convergence speed are validated by comparison with the particle swarm optimization, which have already been proved for its global convergence when applied to a well-known Goldstein-Price function as a benchmark function. In addition, the algorithm has been applied to the optimal design of an interior permanent magnet synchronous machine aiming for its torque ripple reduction.
A new optimization algorithm for combined processes of deep-drawing and ironing has been created in order to improve these types of axisymmetric components manufacturing procedures. The model provides a comprehensive ...
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ISBN:
(纸本)9781849964319
A new optimization algorithm for combined processes of deep-drawing and ironing has been created in order to improve these types of axisymmetric components manufacturing procedures. The model provides a comprehensive analysis of those phenomena occurring in multi-stage processes of axisymmetric geometry work pieces. The scientific development starts out from works that provide LDR (limiting drawing ratio) solutions based on normal anisotropy value, strain hardering exponent and others parameters which have just been applied to the drawing and redrawing stages so far. The authors extend this work to the ironing stages, and also provide a global and integral scientific solution for the whole process. At the beginning the algorithm provides an initial solution which is afterwards optimized by means of objective functions and constraints. The resolution of the optimization process is carried out by a recursive function that minimizes the total time of the global process. The enhanced solution performs a significant reduction in time and costs of the process. The model allows the modification and correction of certain process variables in order to predict the impact of those that are not fully controllable. The final results are compared using experimental results obtained by the authors, so as to show the reliability of the complete solution.
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