Corner-Boundary Processor Allocation for 3D Mesh-Connected Multicomputers

2015 ◽  
Vol 5 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ismail M. Ababneh ◽  
Saad Bani-Mohammad ◽  
Motasem Al Smadi
Keyword(s):  
System Performance ◽  
Allocation Strategy ◽  
Processor Allocation ◽  
Simulation Experiments ◽  
3D Mesh ◽  
Extensive Simulation ◽  
System Utilization ◽  
Free List ◽  
Simulation Results ◽  
Allocation Strategies

This research paper presents a new contiguous allocation strategy for 3D mesh-connected multicomputers. The proposed strategy maintains a list of maximal free sub-meshes and gives priority to allocating corner and boundary free sub-meshes. The goal of corner and boundary allocation is to decrease the number of leftover free sub-meshes and increase their sizes, which is expected to reduce processor fragmentation and improve overall system performance. The proposed strategy, which is referred to as Turning Corner-Boundary Free List (TCBFL) strategy, is compared, using extensive simulation experiments, to several existing allocation strategies for 3D meshes. These are the First-Fit (FF), Turning First-Fit Free List (TFFFL), and Turning Busy List (TBL) allocation strategies. The simulation results show that TCBFL produces average turnaround times and mean system utilization values that are superior to those of previous strategies.

Submesh Allocation in 3D Mesh Multicomputers Using Free Lists

2015 ◽  
pp. 171-187
Author(s):  
Saad Bani-Mohammad ◽  
Ismail Ababneh ◽  
Motasem Al Smadi
Keyword(s):  
Job Scheduling ◽  
Substantial Effect ◽  
Allocation Strategy ◽  
3D Mesh ◽  
Extensive Simulation ◽  
System Utilization ◽  
Service Demand ◽  
Extensive Evaluation ◽  
Simulation Results ◽  
Allocation Strategies

This chapter presents an extensive evaluation of a new contiguous allocation strategy proposed for 3D mesh multicomputers. The strategy maintains a list of maximal free sub-meshes and gives priority to allocating corner and boundary free sub-meshes. This strategy, which we refer to as Turning Corner-Boundary Free List (TCBFL) strategy, is compared, using extensive simulation experiments, to several existing allocation strategies for 3D meshes. In addition to allocation strategies, two job scheduling schemes, First-Come-First-Served (FCFS) and Shortest-Service-Demand (SSD) are considered in comparing the performance of the allocation strategies. The simulation results show that TCBFL produces average turnaround times and mean system utilization values that are superior to those of the existing allocation strategies. The results also reveal that SSD scheduling is much better than FCFS scheduling. Thus, the scheduling and allocation strategies both have substantial effect on the performance of contiguous allocation strategies in 3D mesh-connected multicomputers.

A New Compacting Non-Contiguous Processor Allocation Algorithm for 2D Mesh Multicomputers

2015 ◽  
Vol 8 (4) ◽  
pp. 57-75 ◽  
Author(s):  
Saad Bani-Mohammad ◽  
Ismail M. Ababneh ◽  
Mohammad Yassen
Keyword(s):  
Performance Improvement ◽  
Communication Overhead ◽  
Allocation Strategy ◽  
Processor Allocation ◽  
Improve Performance ◽  
Simulation Experiments ◽  
Extensive Simulation ◽  
System Utilization ◽  
Selection Of ◽  
Allocation Strategies

In non-contiguous allocation, a job request can be split into smaller parts that are allocated possibly non-adjacent free sub-meshes rather than always waiting until a single sub-mesh of the requested size and shape is available. Lifting the contiguity condition is expected to reduce processor fragmentation and increase system utilization. However, the distances traversed by messages can be long, and as a result the communication overhead, especially contention, is likely to increase. The extra communication overhead depends on how the allocation request is partitioned and assigned to free sub-meshes. In this paper, a new non-contiguous processor allocation strategy, referred to as Compacting Non-Contiguous Processor Allocation Strategy (CNCPA), is suggested for the 2D mesh multicomputers. In the proposed strategy, a job is compacted into free locations. The selection of the free locations has for goal leaving large free sub-meshes in the system. To evaluate the performance improvement achieved by the proposed strategy and compare it against well-known existing non-contiguous allocation strategies, the authors conducted extensive simulation experiments. The results show that the proposed strategy can improve performance in terms of job turnaround times and system utilization.

An Efficient All Shapes Busy List Processor Allocation Algorithm for 3D Mesh Multicomputers

2017 ◽  
Vol 7 (2) ◽  
pp. 10-26 ◽  
Author(s):  
Saad Bani-Mohammad
Keyword(s):  
System Performance ◽  
Turnaround Time ◽  
Allocation Strategy ◽  
Processor Allocation ◽  
3D Mesh ◽  
System Utilization ◽  
Size And Shape ◽  
Shape Constraint ◽  
Scheduling Strategies ◽  
Allocation Strategies

Contiguous processor allocation is useful for security and accounting reasons. This is due to the allocated jobs are separated from one another, where each sub-mesh of processors is allocated to an exclusive job request, and the allocated sub-mesh has the same size and shape of the requested job. The size and shape constraint leads to high processor fragmentation. Most recent contiguous allocation strategies suggested for 3D mesh-connected multiconputers try all possible orientations of an allocation request when allocation fails for the requested orientation, which reduces processor fragmentation and hence improves system performance. However, none of them considers all shapes of the request in the process of allocation. To generalize this restricted rotation, we propose, in this paper, a new contiguous allocation strategy for 3D mesh-connected multicomputers, referred to as All Shapes Busy List (ASBL for short), which takes into consideration all possible contiguous request shapes when attempting allocation for a job request. ASBL depends on the list of allocated sub-meshes, in the method suggested in (Bani-Mohammad et al., 2006), for selecting an allocated sub-mesh. The performance of the proposed ASBL allocation strategy has been evaluated considering several important scheduling strategies under a variety of system loads based on different job size distributions. The simulation results have shown that the ASBL allocation strategy improves system performance in terms of parameters such as the average turnaround time of jobs and system utilization under all scheduling strategies considered.

The Effect of Real Workloads and Synthetic Workloads on the Performance of Job Scheduling for Non-Contiguous Allocation in 2D Mesh Multicomputers

2015 ◽  
Vol 6 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Saad Bani-Mohammad
Keyword(s):  
System Performance ◽  
Job Scheduling ◽  
Allocation Strategy ◽  
Extensive Simulation ◽  
Scheduling Strategy ◽  
Need To Evaluate ◽  
Scheduling Strategies ◽  
Simulation Results ◽  
Allocation Algorithms ◽  
Workload Models

The performance of non-contiguous allocation has been traditionally carried out by means of simulations based on synthetic workloads, and also it can be significantly affected by the job scheduling strategy used for determining the order in which jobs are selected for execution. To validate the performance of the non-contiguous allocation algorithms, there has been a need to evaluate the algorithm's performance based on a real workload trace. In this paper, the performance of the well-known Greedy Available Busy List (GABL) non-contiguous allocation strategy for 2D mesh-connected multicomputers is revisited considering several important job scheduling strategies based on a real workload trace, and the results are compared to those obtained from using a synthetic workload. The scheduling strategies used are the First-Come-First-Served (FCFS), Out-of-Order (OO), and Window-Based job scheduling strategies. These strategies have been selected because they are common and they have been used in related works (Ababneh & Bani-Mohammad, 2011). Extensive simulation results based on synthetic and real workload models indicate that the Window-Based job scheduling strategy can improve both overall system performance and fairness (i.e., maximum job waiting delays) by adopting a large job scheduling window. Moreover, the relative performance merits of the scheduling strategies when a real workload trace is used are in general compatible with those obtained when a synthetic workload is used.

A Geometric Theory for Form, Profile and Orientation Tolerances: Evaluation Algorithms and Simulation Results

1998 ◽  
Author(s):  
J. B. Gou ◽  
Y. X. Chu ◽  
Z. X. Li
Keyword(s):  
Minimization Problem ◽  
Software Package ◽  
Initial Conditions ◽  
Geometric Theory ◽  
Simulation Experiments ◽  
Extensive Simulation ◽  
Minimum Zone ◽  
Linear Programming Problems ◽  
Simulation Results ◽  
Tolerance Verification

Abstract Using the geometric theory for formulation of form, profile and orientation tolerances, we develop a simple geometric algorithm, called the Symmetric Minimum Zone (SMZ) algorithm, to unify the computation of form, profile and orientation tolerances. First, using a technique of numerical analysis, we transform the non-differentiable minimization problem into a differentiable minimization problem over an extended configuration space. Then, we solve the latter problem by computing the solutions of a sequence of linear programming problems which can be easily derived using the geometric properties of SE(3)/G0. The SMZ algorithm is incorporated into a software package called GTPack for tolerance verification. Numerous simulation experiments show that the SMZ algorithm has several important features which could lead to its rapid acceptance in the industry: (1) consistency with the Y14.5M standard, (2) computational efficiency, (3) robustness with respect to variations in initial conditions; and (4) implementational simplicity. We also give extensive simulation results comparing the performances of the SMZ algorithm against the best known algorithms in the literature.

scholarly journals Performance Analysis and Evaluation of Ternary Optical Computer Based on Asynchronous Multiple Vacations

2021 ◽  
Author(s):  
Wang Xianchao ◽  
Wang Xianchuan ◽  
Zhang Jie ◽  
Ling Man ◽  
Hou Dayou ◽  
...  
Keyword(s):  
System Performance ◽  
Scheduling Algorithm ◽  
Processor Allocation ◽  
Simulation Experiments ◽  
Analysis And Evaluation ◽  
Task Scheduling Algorithm ◽  
Computer Based ◽  
Optical Computer ◽  
Optical Processor ◽  
Ternary Optical Computer

Abstract Ternary optical computer(TOC) has become a research hotspot in the field because of the advantages such as inherent parallelism, numerous trits, low power consumption, extendibility, bitwise allocability and dynamical bitwise reconfigurability. Meanwhile, its performance evaluation attracts more and more attentions from potential users and researchers. To model its computing ecology more accurately, this paper first builds a three-staged TOC service model by introducing asynchronous multi-vacations and tandem queueing, and then proposes a task scheduling algorithm and an optical processor allocation algorithm with asynchronous vacations of some small optical processors after dividing equally the entire optical processor into several small optical processors which can be used independently. At the same time, the analytical model was established to obtain important performance indicators such as response time, the number of tasks and utilization of optical processor, based on M/M/1 and M/M/n queuing system with asynchronous multi-vacations. In addition, relevant numerical simulation experiments are conducted. The results illustrate that the number of small optical processors, vacation rate and the number of small optical processors allowed to be on vacation have important effects on the system performance. Compared with synchronous vacation, asynchronous vacation not only ensures the system to obtain better maintenance but also improves the system performance to some degree.

Investigating the NO-dependent photooxidation of limonene by OH and O3 using the atmosphere simulation chamber SAPHIR

2021 ◽  
Author(s):  
Yat Sing Pang ◽  
Martin Kaminski ◽  
Anna Novelli ◽  
Philip Carlsson ◽  
Ismail-Hakki Acir ◽  
...  
Keyword(s):  
Organic Aerosol ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Reaction Pathways ◽  
Oh Radicals ◽  
Oh Radical ◽  
Simulation Experiments ◽  
Master Chemical Mechanism ◽  
Simulation Results ◽  
Atmosphere Simulation Chamber

<p>Limonene is the fourth-most abundant monoterpene in the atmosphere, which upon oxidation leads to the formation of secondary organic aerosol (SOA) and thereby influences climate and air quality.</p><p>In this study, the oxidation of limonene by OH at different atmospherically relevant NO and HO<sub>2</sub> levels (NO: 0.1 – 10 ppb; HO<sub>2</sub>: 20 ppt) was investigated in simulation experiments in the SAPHIR chamber at Forschungszentrum Jülich. The analysis focuses on comparing measured radical concentrations (RO<sub>2</sub>, HO<sub>2</sub>, OH) and OH reactivity (k<sub>OH</sub>) with modeled values calculated using the Master Chemical Mechanism (MCM) version 3.3.1.</p><p>At high and medium NO concentrations, RO<sub>2</sub> is expected to quickly react with NO. An HO<sub>2</sub> radical is produced during the process that can be converted back to an OH radical by another reaction with NO. Consistently, for experiments conducted at medium NO levels (~0.5 ppb, RO<sub>2</sub> lifetime ~10 s), simulated RO<sub>2</sub>, HO<sub>2</sub>, and OH agree with observations within the measurement uncertainties, if the OH reactivity of oxidation products is correctly described.</p><p>At lower NO concentrations, the regeneration of HO<sub>2</sub> in the RO<sub>2</sub> + NO reaction is slow and the reaction of RO<sub>2</sub> with HO<sub>2</sub> gains importance in forming peroxides. However, simulation results show a large discrepancy between calculated radical concentrations and measurements at low NO levels (<0.1 ppb, RO<sub>2</sub> lifetime ~ 100 s). Simulated RO<sub>2</sub> concentrations are found to be overestimated by a factor of three; simulated HO<sub>2</sub> concentrations are underestimated by 50 %; simulated OH concentrations are underestimated by about 35%, even if k<sub>OH</sub> is correctly described. This suggests that there could be additional RO<sub>2</sub> reaction pathways that regenerate HO<sub>2</sub> and OH radicals become important, but they are not taken into account in the MCM model.</p>

scholarly journals Hybrid Chirp Signal Design for Improved Long-Range (LoRa) Communications

Signals ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 1-10
Author(s):  
Md. Noor-A-Rahim ◽  
M. Omar Khyam ◽  
Apel Mahmud ◽  
Xinde Li ◽  
Dirk Pesch ◽  
...  
Keyword(s):  
Long Range ◽  
Bit Error Rate ◽  
Modulation Scheme ◽  
Signal Design ◽  
Chirp Signal ◽  
Performance Gain ◽  
Extensive Simulation ◽  
Noise Interference ◽  
Chirp Signals ◽  
Simulation Results

Long-range (LoRa) communication has attracted much attention recently due to its utility for many Internet of Things applications. However, one of the key problems of LoRa technology is that it is vulnerable to noise/interference due to the use of only up-chirp signals during modulation. In this paper, to solve this problem, unlike the conventional LoRa modulation scheme, we propose a modulation scheme for LoRa communication based on joint up- and down-chirps. A fast Fourier transform (FFT)-based demodulation scheme is devised to detect modulated symbols. To further improve the demodulation performance, a hybrid demodulation scheme, comprised of FFT- and correlation-based demodulation, is also proposed. The performance of the proposed scheme is evaluated through extensive simulation results. Compared to the conventional LoRa modulation scheme, we show that the proposed scheme exhibits over 3 dB performance gain at a bit error rate of 10−4.

scholarly journals Game-based cache allocation strategy for ICN slicing

2021 ◽  
Vol 336 ◽  
pp. 05030
Author(s):  
Liping Ge ◽  
Jinhe Zhou
Keyword(s):  
Equilibrium Solution ◽  
Base Station ◽  
Virtual Network ◽  
Game Model ◽  
Allocation Strategy ◽  
Newton Iterative Method ◽  
Content Acquisition ◽  
Simulation Results ◽  
Cache Allocation ◽  
Cooperative Game Model

To reduce the delay of content acquisition, this paper proposes a game-based cache allocation strategy in the Information-Centric Network (ICN) slice. The cache resource allocation of different mobile virtual network operators (MVNOs) is modeled as a non-cooperative game model. The Newton iterative method is used to solve this problem, and the cache space allocated by the base station for each MVNO is obtained. Finally, the Nash equilibrium solution is obtained. Simulation results show that the proposed algorithm can reduce the delay.

Fuzzy Logic Controller for Force Feedback Control of Quadcopter via Tether

2020 ◽  
Author(s):  
Bennett Breese ◽  
Drew Scott ◽  
Shraddha Barawkar ◽  
Manish Kumar
Keyword(s):  
Fuzzy Logic ◽  
Control Strategy ◽  
Fuzzy Logic Controller ◽  
Force Feedback ◽  
Power Transmission ◽  
Extensive Simulation ◽  
Control Scheme ◽  
Area Surveillance ◽  
Simulation Results ◽  
Long Endurance

Abstract Tethered drone systems can be used to perform long-endurance tasks such as area surveillance and relay stations for wireless communication. However, all the existing systems use tethers only for data and power transmission from a stationary point on the ground. This work presents a control strategy that enables a quadcopter to follow a moving tether anchor. A force feedback controller is implemented using Fuzzy Logic. Using force-based strategy provides effective compliance between the tether’s anchor and the drone. The drone can thus be controlled by mere physical movement/manipulation of tether. This enhances the safety of current tethered drone systems and simplifies the flying of drones. Fuzzy Logic provides an intuitive edge to the control of such systems and allows handling noise in force sensors. Extensive simulation results are presented in this paper showing the effectiveness of the proposed control scheme.

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