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.

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.

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.

Asset Allocation Strategies and Commodities

2018 ◽  
Author(s):  
Claudio Boido
Keyword(s):  
Asset Allocation ◽  
Asset Management ◽  
Central Banking ◽  
Fixed Income ◽  
Fixed Income Securities ◽  
Asset Classes ◽  
Alternative Beta ◽  
Asset Managers ◽  
Selection Of ◽  
Allocation Strategies

As a result of the financial crisis of 2007–2008 and subsequent central banking decisions, the asset management industry changed its asset allocation choices. Asset managers are focusing their attention on the search for new asset classes by taking advantage of the new opportunities to capture risk premia with the aim of exceeding the returns given by traditional investments, including traded equities, fixed income securities, and cash. By doing so, they are trying to improve the selection of alternative assets, such as commodities that sometimes have relatively low correlations with traditional assets. The chapter begins by describing the principles of asset allocation, distinguishing between passive and active asset allocation, also focusing on beta and alternative beta. It then concentrates on how investors can gain exposure to commodities through different investment vehicles and strategies.

scholarly journals Modeling Rasmussen’s dynamic modeling problem: drift towards a boundary of safety

2021 ◽  
Author(s):  
J. Bradley Morrison ◽  
Robert L. Wears
Keyword(s):  
High Risk ◽  
Conceptual Model ◽  
Performance Improvement ◽  
Dynamic Modeling ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
System Safety ◽  
Simulation Experiments ◽  
Scenarios Simulation ◽  
Very High

AbstractWe build a system dynamics model based on a conceptual model originally proposed by safety scientist Jens Rasmussen to explore the dynamics of a safety system subject to pressures for performance improvement. Rasmussen described forces that generate a drift in the boundary of acceptable performance that can push the organization towards “flirting with the margin” and thus operate at very high risk of catastrophic safety failure. Simulations of the model faithfully replicate the behavior described by Rasmussen and others in a variety of scenarios. Simulation experiments further illuminate the potential for risky behavior and point towards some approaches to better system safety.

A Decade's Worth

2020 ◽  
pp. 179-200
Author(s):  
Ria Roy
Keyword(s):  
Construction Industry ◽  
Performance Improvement ◽  
Cash Flow ◽  
Employee Turnover ◽  
Turnover Rate ◽  
Improve Performance ◽  
Deep Dive ◽  
Construction Company ◽  
Financing Costs

After witnessing a year-on-year growth of 50% since its inception in 1993, Ziggurat Developers was well on its way to being the next niche, technically sophisticated, and edgy construction company in Mumbai, India. This case takes a deep dive into how winning a prestigious construction contract in the country led to Ziggurat's loss of revenue, cash flow deficits, year-on-year losses, high financing costs, loss of banking, idling of resources, loss of credibility, and high employee turnover rate. Instead of these significant contracts providing a strong foothold in the construction industry, it destroyed Ziggurat and the recovery took a decade. Performance improvement is often the study of how to improve performance when discrepancies are confined to a silo or a subset of functions within an organization. But how do you get back to exemplary performance when you are boxed in and there is no way out?

scholarly journals Research on Performance Improvement of Photovoltaic Cells and Modules Based on Black Silicon

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 753
Author(s):  
Zijian Chen ◽  
Haoyuan Jia ◽  
Yunfeng Zhang ◽  
Leilei Fan ◽  
Haina Zhu ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Performance Improvement ◽  
Oxygen Flux ◽  
Electrical Performance ◽  
Black Silicon ◽  
Flux Control ◽  
Pv Module ◽  
Oxidation Step ◽  
Selection Of ◽  
Silicon Cell

This paper mainly studied the electrical performance improvement of black silicon photovoltaic (PV) cells and modules. The electrical performance of the cells and modules matched with black silicon was optimized through three different experiments. Firstly, in the pre-cleaning step, the effect of lotion selection on the cell performance was studied. Compared with alkaline lotion, using acidic lotion on black silicon wafer can achieve an efficiency improvement of the black silicon cell by nearly 0.154%. Secondly, the influence of oxygen flux control of the thermal oxidation step on the improvement of cell efficiency was studied. The addition of the thermal oxidation step and its oxygen flux control resulted in an efficiency increase of the black silicon cell of nearly 0.11%. The most optimized volume control of the oxygen flux is at 2200 standard cubic centimeter per minute (SCCM). Finally, in the module packaging process, the selection of components will also greatly affect the performance of the black silicon PV module. The most reasonable selection of components can increase the output power of the black silicon PV module by 6.13 W. In a word, the technical indication of the electrical performance improvement suggested in this study plays an important guiding role in the actual production process.

Fragment Re-Allocation Strategy Based on Hypergraph for NoSQL Database Systems

2016 ◽  
Vol 8 (3) ◽  
pp. 1-23 ◽  
Author(s):  
Zhikun Chen ◽  
Shuqiang Yang ◽  
Yunfei Shang ◽  
Yong Liu ◽  
Feng Wang ◽  
...  
Keyword(s):  
Database Systems ◽  
Communication Cost ◽  
Allocation Strategy ◽  
Hypergraph Partitioning ◽  
Computing Model ◽  
Operation Pattern ◽  
Nosql Database ◽  
High Scalability ◽  
Weighted Hypergraph ◽  
Allocation Strategies

NoSQL database is famed for the characteristics of high scalability, high availability, and high fault-tolerance. It is used to manage data for a lot of applications. The computing model has been transferred to “computing close to data”. Therefore, the location of fragment directly affects system's performance. Every site's load dynamical changes because of the increasing data and the ever-changing operation pattern. So system has to re-allocate fragment to improve system's performance. The general fragment re-allocation strategies of NoSQL database scatter the related fragments as possible to improve the operations' parallel degree. But those fragments may interact with each other in some application's operations. So the high parallel degree of operation may increase system's communication cost such as data are transferred by network. In this paper, the authors propose a fragment re-allocation strategy based on hypergraph. This strategy uses a weighted hypergraph to represent the fragments' access pattern of operations. A hypergraph partitioning algorithm is used to cluster fragments in the strategy. This strategy can improve system's performance according to reducing the communication cost while guaranteeing the parallel degree of operations. Experimental results confirm that the strategy will effectively contribute in solving fragment re-allocation problem in specific application environment of NoSQL database system, and it can improve system's performance.

Sign in / Sign up

Export Citation Format

Share Document