Two-mode overconstrained three-DOFs rotational-translational linear-motor-based parallel-kinematics mechanism for machine tool applications

The paper introduces a family of three-DOFs translational-rotational Parallel-Kinematics Mechanisms (PKMs) as well as the mobility analysis of such family using Lie-group theory. Each member of this family has two-rotational one-translational DOFs. A novel mechanism is presented and analyzed as a representative of that family. The use and the practical value of that modular mechanism are emphasized.

A parallel downloading algorithm for redundant networks

In this paper, we study the downloading mechanism of BitTorrent (or BT), a P2P based popular and convenient parallel downloading software tool, point out some of its limitations, and propose an algorithm to improve its performance. In particular, we address the limitations of BT by using neighbours in P2P networks to resolve the redundant copies problem and to optimise the downloading speed. Our preliminary experiments show that the proposed enhancement algorithm works well.

An enhanced parallel downloading algorithm for BT

BitTorrent (or BT) is a P2P based popular and convenient parallel downloading software tool. In this paper, we study the downloading mechanism of BitTorrent, point out some of its limitations, and propose an algorithm to improve its performance. Two major limitations of BitTorrent are, first its downloading speed is slow at the beginning of a downloading or when there is only a few clients. Second, current algorithms cannot achieve the best
parallel downloading degree as the selection of sub-pieces is random, and a file may not be downloaded when the file provider leaves the network unexpectedly. In this paper we address these problems by using neighbours in P2P networks to resolve the redundant copies and to optimise the download speed. Our preliminary experiments show that the proposed enhancement algorithm works well.

Delay control and parallel admission algorithms for real-time anycast flow

An anycast flow is a flow that can be connected to any one of the members in a group of designated (replicated) servers (called anycast group). In this paper, we derive a set of formulas for calculating the end-to-end delay bound for the anycast flows and present novel admission control algorithms for anycast flows with real-time constraints. Given such an anycast group, our algorithms can effectively select the paths for anycast flows' admission and connection based on the least end-to-end delay bounds evaluated. We also present a parallel admission control algorithm that can effectively calculate the available paths with a short delay bound for different destinations in the anycast group so that a best path with the shortest delay bound can be chosen.

A parallel DNA fragment assembly algorithm based on eulerian superpath approach

Fragments assembly is among the core problems in the research of Genome. Although many assembly tools based on the "overlap-layout-consensus" paradigm are widely used such as in the Human Genome Project currently, they still can not resolve the "repeats problem" in the DNA sequencing. For the purpose of resolving such problem, Pevzner et al. put forward a new Euler Superpath assembly algorithm. But it needs a big and complex de Bruijin graph which consumes large amounts of memories i.e. becomes the bottleneck of the performance. We present a parallel DNA fragment assembly algorithm based on the Eularian Superpath theory and solve the bottleneck in the current assembly program. The experimental results demonstrate that our approach has a good scalability, and can be used in DNA assembly of middle and large size of eukaryote genome.

Heavy tools manipulation by low powered direct-drive five-bar parallel robot

This paper presents a simple and available system for manipulation of heavy tools by low powered manipulator for industrial applications. In the heavy manufacturing industries, sometimes, heavy tools are employed for different types of work. But the application of robots with heavy tools is not possible due to the limited torque limits of actuators. Suspended tool systems (STS) have been proposed to manipulate heavy tools by low powered robot-arm for this purpose. A low powered five-bar direct-drive parallel manipulator is designed and constructed to manipulate heavy tools suspended from a spring balancer. The validity, usefulness, and effectiveness of the suspended tool system are shown by experimental results.

Human sympathetic nerve biology : parallel influences of stress and epigenetics in essential hypertension and panic disorder

Patients with panic disorder provide a clinical model of stress. On a "good day," free from a panic attack, they show persistent stress-related changes in sympathetic nerve biology, including abnormal sympathetic nerve single-fiber firing ("salvos" of multiple firing within a cardiac cycle) and release of epinephrine as a cotransmitter. The coreleased epinephrine perhaps originates from in situ synthesis by phenylethanolamine N-methyltransferase (PNMT). In searching for biological evidence that essential hypertension is caused by mental stress—a disputed proposition—we note parallels with panic disorder, which provides an explicit clinical model of stress: (1) There is clinical comorbidity; panic disorder prevalence is increased threefold in essential hypertension. (2) For both, epinephrine cotransmission is present in sympathetic nerves. (3) In panic disorder and essential hypertension, but not in health, single-fiber sympathetic nerve firing salvos occur. (4) Tissue nerve growth factor is increased in both conditions (nerve growth factor is a stress reactant). (5) There is induction of PNMT in sympathetic nerves. Essential hypertension exhibits a further manifestation of mental stress: there is activation of noradrenergic brain stem neurons projecting to the hypothalamus and amygdala. These pathophysiological findings strongly support the view that chronic mental stress is important in the pathogenesis of essential hypertension. A hypothesis now under test is whether in both disorders, under prevailing conditions of ongoing stress, PNMT induced in sympathetic nerves acts as a DNA methylase, causing the norepinephrine transporter (NET) gene silencing that is present in both conditions. PNMT can have an intranuclear distribution, binding to DNA. We have demonstrated that the reduced neuronal noradrenaline reuptake present in both disorders does have an epigenetic mechanism, with demonstrable reduction in the abundance of the transporter protein, the NET gene silencing being associated with DNA binding by the methylation-related inhibitory transcription factor MeCP2.

Load balancing based concurrent execution of NAS parallel benchmarks with BYTE sequential benchmarks on a non-dedicated cluster

Dedicated clusters are becoming commonly used for high performance parallel processing. Computers of a non-dedicated cluster are often idle or lightly loaded. These under utilised computers can be employed to execute parallel applications. Thus, they have to be shared by parallel and sequential applications, which could lead to the improvement of their execution performance. There is a lack of experimental study showing the behaviour and performance of executing parallel and sequential applications concurrently on a non-dedicated cluster. We present the result of an experimental study into load balancing of a mixture of parallel and sequential applications on a non-dedicated cluster.

A study of the concurrent execution of parallel and sequential applications on a non-dedicated cluster

Computers of a non-dedicated cluster are often idle (users attend meetings, have lunch or coffee breaks) or lightly loaded (users carry out simple computations to support problem solving activities). These underutilised computers can be employed to execute parallel applications. Thus, these computers can be shared by parallel and sequential applications, which could lead to the improvement of their execution performance. However, there is a lack of experimental study showing the applications’ performance and the system utilization of executing parallel and sequential applications concurrently and concurrent execution of multiple parallel applications on a non-dedicated cluster. Here we present the result of an experimental study into load balancing based scheduling of mixtures of NAS Parallel Benchmarks and BYTE sequential applications on a very low cost non-dedicated cluster. This study showed that the proposed sharing provided performance boost as compared to the execution of the parallel load in isolation on a reduced number of computers and better cluster utilization. The results of this research were used not only to validate other researchers’ result generated by simulation but also to support our research mission of widening the use of non-dedicated clusters. Our promising results obtained could promote further research studies to convince universities, business and industry, which require a large amount of computing resources, to run parallel applications on their already owned non-dedicated clusters.

A parallel download protocol for internet-based distributed systems

Parallel transfer of large amounts of data is attractive as (i) the data can be received in less time and (ii) is more resilient to connection failures. This is often used in e-Science under the field of data sharing. Data from one research project should be easily assessable to others regardless of the size of the data thus parallelism is used to help share the data quickly. However, there are many tasks to be carried out to make it possible: replica discovery and load detection just to name two. A common problem with most solutions is they overlook some tasks such as load detection. PHTTP is an innovate protocol which handles the tasks behind parallel transfer while presenting itself as a normal sequential transfer.

An intelligent energy management model for a parallel hybrid vehicle under combined loads

To exploit the benefits offered by parallel HEVs, an intelligent energy management model is developed and evaluated in this paper. Despite most existing works, the developed model incorporates combined wind/drag, slope, rolling, and accessories loads to minimise the fuel consumption under varying driving conditions. A slope prediction unit is also employed. The engine and the electric motor can output power simultaneously under a heavy-load or a slopped road condition. Two simulation were conducted namely slopped-windy-prediction and slopped-windy-prediction-hybrid. The results indicate that the vehicle speed and acceleration is smoother where the hybrid component was included. The average fuel consumption for the first and second simulations were 7.94 and 7.46 liter/100 km, respectively.