Static Balancers Research Articles

An MCDM optimization based dynamic workflow scheduling used to handle priority tasks for fault tolerance in IIOT

Cloud computing's prominence can be mainly attributed to its convenient on-demand service delivery via the internet. The difficulty in managing these requests and allocating them optimally is exacerbated by the growing number of users making them and the variety of criteria used to apply cloud resources. Some of these difficulties include scheduling work while considering the user's Quality of Service (QoS) preferences, ensuring adequate load balancing, and adapting to the ever-changing conditions of the cloud environment. As server capabilities evolve, static load balancers, which distribute requests using fixed ratios of available resources, fail to provide optimum throughput. It has been shown that no other scheduling algorithms offer an adaptive method that considers both load balancing and maximizing the QoS criteria. The authors of this study present a novel adaptive strategy for dealing with this issue by fusing the best-worst multi-criteria decision-making method (BWM) with the compromise ranking method (VIKOR). Task priorities are determined by using the VIKOR method as a decision-maker. Numerical experiments are used to verify the validity of the suggested method, and the methodology is compared to other scheduling methods in terms of a variety of performance criteria. The simulation findings show that the presented method outperforms its rivals regarding throughput, makespan, waiting time, virtual machine (VM) utilization, and VM usage cost across the board of simulated experimental settings.

Straightforward Heterogeneous Computing with the oneAPI Coexecutor Runtime

Heterogeneous systems are the core architecture of most computing systems, from high-performance computing nodes to embedded devices, due to their excellent performance and energy efficiency. Efficiently programming these systems has become a major challenge due to the complexity of their architectures and the efforts required to provide them with co-execution capabilities that can fully exploit the applications. There are many proposals to simplify the programming and management of acceleration devices and multi-core CPUs. However, in many cases, portability and ease of use compromise the efficiency of different devices—even more so when co-executing. Intel oneAPI, a new and powerful standards-based unified programming model, built on top of SYCL, addresses these issues. In this paper, oneAPI is provided with co-execution strategies to run the same kernel between different devices, enabling the exploitation of static and dynamic policies. This work evaluates the performance and energy efficiency for a well-known set of regular and irregular HPC benchmarks, using two heterogeneous systems composed of an integrated GPU and CPU. Static and dynamic load balancers are integrated and evaluated, highlighting single and co-execution strategies and the most significant key points of this promising technology. Experimental results show that co-execution is worthwhile when using dynamic algorithms and improves the efficiency even further when using unified shared memory.

An adaptive scheduling approach based on integrated best-worst and VIKOR for cloud computing

Cloud computing is a new distributed environment to provide on-demand services through the internet and has become popular due to this specific feature. By increasing the count of user requests and different criteria in applying the cloud resources, there exist challenges for managing these requests and their optimal allocation. Some of these challenges consist of considering the dynamic nature of the cloud environment, finding the values of the different criteria and the scheduling tasks by considering the user’s Quality of Service (QoS) preferences, load balancing, etc. Static load balancers distribute requests based on pre-known server capability ratios and these models do not produce optimal throughput when the server capabilities change overtime. None of the other scheduling algorithms is able to provide an adaptive approach to consider both of the load balancing and optimizing the QoS requirements. To solve this problem, this paper proposes a new adaptive approach based on a combination of the concept of the best-worst multi criteria decision-making method (BWM), and compromise ranking method (VIKOR). The VIKOR method is implemented as a decision maker to specify the task priorities. The proposed approach is validated with numerical experiments and is compared with the existing scheduling algorithms over different performance metrics. The simulation results indicate that the proposed approach improves the performance metrics like throughput, makespan, waiting time, virtual machine (VM) utilization and VM usage cost for all considered experimental scenarios in comparison with its counterparts.

Transformation of static balancer from truss to linkage

This paper presents a transformation method by which a static balancer of a truss is transformed into static balancers of various mechanisms. For conventional design methods the kinematics and potential energy of every mechanism should be computed to design a static balancer. For the proposed design method, however, no computation of kinematics and potential energy is necessary to obtain static balancers of various mechanisms, once a static balancer of a truss has been designed. The concepts of the Baranov truss and associated linkage are adopted to determine transformation relations. Conversion rules are developed in the viewpoint of gravitational torques and deletion rules are determined to apply conversion rules to the design equation. Static balancers of various mechanisms (four-bar linkage, slider crank mechanism, Watt mechanism and sliding mechanism derived from the watt mechanism) are derived from those of the five-link and seven-link Baranov trusses in this paper. Simulations results showed that complete gravity compensation is achieved for all derived mechanisms from Baranov trusses.

Design of gravity compensators using the Stephenson and Watt mechanisms

This paper evaluates the design method for a gravity compensator using associated linkages. For conventional design methods the kinematics and potential energy of every mechanism should be computed to design a static balancer. For the proposed design method, however, no computations of kinematics and potential energy are necessary to obtain static balancers of various mechanisms, once a static balancer of an associated linkage has been designed. The deletion rules (i.e., transformation relations) are derived with the concept of the associated linkage. The Stephenson and Watt linkages are adopted as associated linkages that contain ternary links and multi-loops. Gravity compensators of the associated linkages are designed based on the space mapping method. When a ternary link becomes a slider, several unit gravity compensators are attached at the ternary link and can be merged into an equivalent gravity compensator. In consideration of the equivalent gravity compensator, a new deletion rule is introduced and incorporated in the set of the original deletion rules. Various gravity compensators are derived applying the new deletion rules to gravity compensators of associated linkages. Performances of the various gravity compensators are evaluated with simulations.

The application of static load balancers in parallel compositional reservoir simulation on distributed memory system

Compositional reservoir simulation depicts the complex behaviors of all the components in gaseous, liquid, and oil phases. It helps to understand the dynamic changes in reservoirs. Parallel computing is implemented to speed up simulation in large scale fields. However, there is still many challenges in obtaining efficient and cost-effective parallel reservoir simulation. Load imbalance on processors in the parallel machine is a major problem and it severely affects the performance of parallel implementation in compositional reservoir simulators. This article presents a new approach to the reduction of load imbalance among processors in large scale parallel compositional reservoir simulation. The approach is based on graph partitioning techniques: Metis partitioning and spectral partitioning. These techniques treat the simulation grid, or the mesh, as a graph constituted by vertices and edges, and then partition the graph into smaller domains. Metis and spectral partitioning techniques are advantageous because they take into account the potential computational load of each grid block in the mesh and generate smaller partitions for heavy computational load areas and larger partitions for light computational load areas. In our case, the computational load is represented by transmissibility. After new partitions are generated, each of them is assigned to a processor in the parallel machine and new parallel reservoir simulation can be conducted. Traditionally, the intuitive 2D decomposition is frequently used to partition the simulation grid into small rectangles, and this is a major source of load imbalance. The performance of parallel compositional simulation based on our partitioning techniques is compared with the most commonly used 2D decomposition and it is found that load imbalance in our new simulations is reduced when compared with the traditional 2D decomposition. This study improves the efficiency of compositional simulation and eventually makes it more cost-effective for hydrocarbon simulation on mega-scale reservoir models.

A sliding window based Self-Learning and Adaptive Load Balancer

A load balancer distributes load among individual resources to minimize the response time, maximize the throughput and efficiently utilize the resources. Static load balancers distribute requests based on pre-known server capability ratios. Dynamic load balancers either observe or collect the performance indicating attributes of the servers, and distribute the load based on the analysis performed on the observed or collected data. The observation based load balancers use the quickest response time and the least number of connections to select a server to process an arrived request. Both the static load balancing and observation based models do not produce optimal throughput when the server capabilities change over time. This paper introduces a Sliding window based Self-learning and Adaptive Load Balancer (SSAL) that optimizes throughput in both the stable and unstable server environments. The SSAL logically divides time into fixed size intervals, assigns the requests in batches and makes corrections based on the performance of the servers observed in each interval. The SSAL (i) discovers the initial capabilities of the servers and perform incremental corrections needed in the subsequent intervals, (ii) produces throughput, better than the static load balancing model in stable environments, and (iii) produces throughput better than the quickest response time and least connections based models in unsteady environments. Experiments are conducted to compare the performance of the SSAL to other models under various stable and unstable server environments. The experimental results confirm that the SSAL produces optimal throughput in both stable and unstable environments, and the turnaround time similar to or better than that of the observation based models. The proposed model is useful where the capabilities of the servers change over time and the optimal throughput is required.

Stiffness Compensation Mechanism for Body Powered Hand Prostheses with Cosmetic Covering

Body powered hand prostheses require high physical user effort. This is caused by the stiffness of the cosmetic covering, or cosmetic glove. This paper aims to present a new concept of a mechanism for the compensation of the nonlinear stiffness of body powered hand prostheses by using static balancers with a nonlinear behavior. This concept is based on a cooperative action of snap-through behavior in multiple bi-stable spring mechanisms to create the nonlinear balancing force. To demonstrate the efficiency of the concept, an optimized design for a case study of a child-size hand prosthesis is also presented. A pattern search method was applied for the optimization. As a result, the calculated stiffness and thereby the operating effort was reduced by 96%. It can be concluded from the conceptual and numerical results that the presented concept provides a highly efficient solution to the discussed problem.

Energy-free adjustment of gravity equilibrators by adjusting the spring stiffness

Static balancing is a useful concept to reduce the operating effort of mechanisms. Spring mechanisms are used to achieve a constant total potential energy, thus eliminating any preferred position. Quasi-statically, the mechanism, once statically balanced, can be moved virtually without the operating energy. In some cases, it is desirable to adjust the characteristic of the balancer, for instance, due to a change in the payload in a gravity balanced mechanism. The adjustment of current static balancers requires significant operating energy. This paper will present a novel variant to adjust the spring- and linkage-based static balancers without the need for external energy. The variant makes use of the possibility to adjust the spring stiffness in an energy-conserving way by adjusting the number of active coils. The conditions under which it functions properly will be given, and a proof of the concept model will be shown.

Gravity-Balanced Arm Support With Energy-Free Adjustment

People with neuromuscular diseases have very limited muscle force. Many of them rely on mobile arm supports to move their arms. Most of these supports incorporate gravity balancers, i.e., spring-loaded mechanisms that achieve a constant total potential energy, thus eliminating any preferred position. The springs and the mechanism topology and dimensions are designed to exactly or approximately balance the weight of the user’s arm. Quasistatically, the mechanism, once statically balanced, can thus be moved virtually without operating energy. In case of change of effective arm weight, e.g., due to picking up an object or putting on a coat, the support mechanism should ideally be readjusted. In all available support mechanisms, this adjustment is associated with considerable mechanical effort, while clearly this application would benefit greatly from an energy-free adjustment. This paper will present an arm support that includes a novel design concept to adjust spring-based static balancers with no need for external energy. This concept will be explained, and several variants will be shown. Subsequently, the application of this concept in a mobile arm support will be described in detail, including preliminary clinical trial results.

The application of the induction voltage regulator

This paper reviews the general applicaion of induction regulators to feeder systems and distribution networks.The problem of fully automatic control is dealt with and various methods of parallel working are discussed.The point of application of the regulator in the system is considered from its practical and economic aspects, and the use of static balancers in conjunction with the regulator is outlined.The financial aspect of induction regulator application to distribution networks is given.Twin polyphase induction regulators giving a quadrature component for load control on closed-loop interconnectors are described.Finally, special applications and connections of induction regulators are included.

Discussion on “A method of regulating the voltages on the two sides of a three-wire D.C. system equalized by static balancers”

Discussion on “A method of regulating the voltages on the two sides of a three-wire D.C. system equalized by static balancers”

A method of regulating the voltages on the two sides of a three-wire D.C. system equalized by static balancers

The merits of the static balancer are compared with those of rotary balancers, the chief disadvantage of the former being that the voltage on the two sides of the three-wire system cannot be regulated without the aid of a mid-wire booster.An arrangement is described whereby this disadvantage can be overcome by the use of tappings other than the central point of the winding of the balancer, rectifying the voltage between these tappings and the central point, and inserting the rectified E. M. F. into the side of the system the voltage of which it is required to raise.