Interrupt Mechanism Research Articles

The interrelation between mechanical characteristics of contracting muscle, cross-bridge internal structure, and the mechanism of chemomechanical energy transduction

The cross-bridge working stroke is regarded as a continuous (without jumps) change of myosin head internal state under the action of a force exerted within the nucleotide-binding site. Involvement of a concept of continuous cross-bridge conformation enables discussion of the nature of the force propelling muscle, and the Coulomb repulsion of like-charged adenosine triphosphate (ATP) fragments ADP(2-) and P (i) (2-) can quite naturally be considered as the source of this force. Two entirely different types of working stroke termination are considered. Along with the fluctuation mechanism, which controls the working stroke duration t (w) at isometric contraction, another interrupt mechanism is initially taken into account. It is triggered when the lever arm shift amounts to the maximal value S≈11nm, the back door opens, and P(i) crashes out. As a result, t (w) becomes inversely proportional to the velocity v of sliding filaments t (w)≈S/v for a wide range of values of v. Principal features of the experimentally observed dependences of force, efficiency, and rate of heat production on velocity and ATP concentration can then be reproduced by fitting a single parameter: the velocity-independent time span t (r) between the termination of the last and beginning of the next working stroke. v becomes the principal variable of the model, and the muscle force changes under external load are determined by variations in v rather than in the tension of filaments. The Boltzmann equation for an ensemble of cross-bridges is obtained, and some collective effects are discussed.

Modeling Interrupts for Software-Based System-on-Chip Verification

The interrupt mechanism in a system-on-chip (SoC) joins the SoCs hardware and software behaviors. We model interrupts as logical rather than physical events and accordingly provides guidelines to compose software components including interrupt-service-routines. As a benefit, classical indeterministic behaviors (due to the parallelism) in the software domain, such as preemption and nesting, can be constructed as early as raw hardware components are being integrated. In effect, while the interrupt mechanism itself is under rigorous stress, it is simultaneously driving the exercise of the entire SoC. This effect can be observed through software profiling at the hardware integration stage.

Frictionally Excited Thermoelastic Instability and the Suppression of Its Exponential Rise in Disc Brakes

This paper deals with processes of thermoelastic instability occurring on brake systems that become evident as a non-uniform distribution of temperature with hot spots on contact surfaces. Thermoelastic instability is accompanied by the exponential rising of temperature amplitudes of hot spots during its initial linear phase. The authors discuss different mechanisms of interruption of the growth, based on experimental and computational results. An example of experimental data is presented for the case of a disc brake.

Soft interruption handling mechanism to optimize handling performance for Linux network

As the most strict bottom half handling mechanism of interruption on time accuracy,soft interrupt mechanism plays an irreplaceable role in the process of handling network packet.However,unalterable circular check times taken by soft interruption handling function causes system unable to handle packets effectively under high traffic load.This paper presented a methodology of adaptive circular checking times to optimize soft interruption handling mechanism.Test shows that compared with the former mechanism,current soft interruption mechanism can handle more soft interruption routines in the same condition,i.e.capturing more network packets.The methodology improves the system′s capacity to handle soft interruptions and optimizes the handling capability of Linux network.

The Role of Renin-Angiotensin System in Prothrombotic State in Essential Hypertension

Rheological, haemostatic, endothelial and platelet abnormalities appear to play a role in the thrombotic complications of hypertension. This prothrombotic/hypercoagulable state in hypertension may contribute to the increased risk and severity of target organ damage. It can be induced by the activated renin-angiotensin system (RAS), with abnormalities in endothelial and platelet function, coagulation and fibrinolysis. Treatment of uncomplicated essential hypertension by RAS targeting antihypertensive therapy could result in a reversal of prothrombotic abnormalities, contributing to a reduction of thrombosis-related complications. Since angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) have two distinct mechanisms of RAS interruption, it is hypothesized that each therapy might have different impact on the prothrombotic state in hypertensive patients. Some studies demonstrate a beneficial effect of both ACE inhibitors and ARBs on prothrombotic state, in addition to their efficacy to normalize elevated blood pressure. The potentially antithrombotic effect of the RAS inhibiting agents may in turn support the preservation of cardiovascular function. Available data may offer an additional explanation for the efficacy of the RAS targeting agents in the prevention of cardiovascular events in patients with atherosclerotic vascular disease.

Debugging GPU stream programs through automatic dataflow recording and visualization

We present a novel framework for debugging GPU stream programs through automatic dataflow recording and visualization. Our debugging system can help programmers locate errors that are common in general purpose stream programs but very difficult to debug with existing tools. A stream program is first compiled into an instrumented program using a compiler. This instrumenting compiler automatically adds to the original program dataflow recording code that saves the information of all GPU memory operations into log files. The resulting stream program is then executed on the GPU. With dataflow recording, our debugger automatically detects common memory errors such as out-of-bound access, uninitialized data access, and race conditions -- these errors are extremely difficult to debug with existing tools. When the instrumented program terminates, either normally or due to an error, a dataflow visualizer is launched and it allows the user to examine the memory operation history of all threads and values in all streams. Thus the user can analyze error sources by tracing through relevant threads and streams using the recorded dataflow. A key ingredient of our debugging framework is the GPU interrupt , a novel mechanism that we introduce to support CPU function calls from inside GPU code. We enable interrupts on the GPU by designing a specialized compilation algorithm that translates these interrupts into GPU kernels and CPU management code. Dataflow recording involving disk I/O operations can thus be implemented as interrupt handlers. The GPU interrupt mechanism also allows the programmer to discover errors in more active ways by developing customized debugging functions that can be directly used in GPU code. As examples we show two such functions: assert for data verification and watch for visualizing intermediate results.

Ictogênese, epileptogênese e mecanismo de ação das drogas na profilaxia e tratamento da epilepsia

INTRODUÇÃO: O neurologista que deseja manejar adequadamente seus pacientes com epilepsia deve estar familiarizado com os mecanismos de geração, propagação e interrupção das crises epilépticas. No presente artigo, fazemos uma breve revisão a respeito dos mecanismos de geração das crises em pacientes com epilepsia (ictogênese) e do processo envolvido no desenvolvimento da epilepsia secundária a uma lesão cerebral (epileptogênese). Paralelamente, apresentamos os mecanismos de ação dos principais fármacos utilizados em cada uma dessas situações, isto é, fármacos antiictogênicos e fármacos antiepileptogênicos. OBJETIVO: Apresentar e discutir os principais conceitos sobre ictogênese, epileptogênese e mecanismo de ação das drogas na profilaxia e tratamento da epilepsia. CONCLUSÃO: Diferentes abordagens farmacológicas têm sido desenvolvidas e testadas com o intuito de bloquear as crises com maior eficiência, bem como impedir o desenvolvimento da epilepsia após uma lesão cerebral. É de se esperar que, com o avanço do conhecimento, novas drogas serão desenvolvidas e possibilitarão um melhor resultado na prevenção e tratamento da epilepsia.

Cost-Effective Prevention of Diarrheal Diseases: A Critical Review

This paper critically reviews the existing research on the cost-effective prevention and treatment of diarrheal diseases, and identifies research priorities in this area aimed at finding ways to reduce the diarrheal disease burden. In contrast to the empirical knowledge base that exists for traditional child health programs to reduce diarrheal morbidity and mortality, evidence on the relative effectiveness and cost-effectiveness of various environmental health interventions is limited and subject to significant methodological concerns. There is a limited understanding of the determinants of longterm water and sanitation technology adoption and behavior change at the individual level. Even less is known about how collective action problems in water and sanitation infrastructure maintenance can be overcome. An agenda for future research includes evaluating alternative transmission interruption mechanisms, improving understanding of the determinants of individual-level technology adoption in the water and sanitation sector, and assessing the quality of infrastructure maintenance under different management schemes.

Numerical simulation and experimental study of a mechanism for Hopkinson bar test interruption

The damage evolution in a material during quasi-static and dynamic tests can be studied by interrupting the test at predetermined elongation values and post-mortem analyses of the specimens. While it is straightforward to interrupt quasi-static tests at a predetermined level of elongation, this interruption presents difficulties at high-strain-rate conditions. In the present work, tests at high strain rate using a split Hopkinson tensile bar have been interrupted by an interruption mechanism as a modification of this device. This interruption mechanism is based on the use of two rings of a soft material that absorb the impact energy by deforming plastically. The influence of the dimensions of damper rings on the stress waves and also the ability of the system to support the interruption of the deformation process were considered in the numerical analyses and verified by the experimental results. The relationship between the recommended ring thickness and maximum reached strain for aluminium alloy A16082 will be presented. Finally, the influence of strain on the damage evolution of the ZC71 particulate-reinforced magnesium matrix was reported.

In-line interrupt handling and lock-up free translation lookaside buffers (TLBs)

The effects of the general-purpose precise interrupt mechanisms in use for the past few decades have received very little attention. When modern out-of-order processors handle interrupts precisely, they typically begin by flushing the pipeline to make the CPU available to execute handler instructions. In doing so, the CPU ends up flushing many instructions that have been brought in to the reorder buffer. In particular, these instructions may have reached a very deep stage in the pipeline - representing significant work that is wasted. In addition, an overhead of several cycles and wastage of energy (per exception detected) can be expected in refetching and reexecuting the instructions flushed. This paper concentrates on improving the performance of precisely handling software managed translation look-aside buffer (TLB) interrupts, one of the most frequently occurring interrupts. The paper presents a novel method of in-lining the interrupt handler within the reorder buffer. Since the first level interrupt-handlers of TLBs are usually small, they could potentially fit in the reorder buffer along with the user-level code already there. In doing so, the instructions that would otherwise be flushed from the pipe need not be refetched and reexecuted. Additionally, it allows for instructions independent of the exceptional instruction to continue to execute in parallel with the handler code. By in-lining the TLB interrupt handler, this provides lock-up free TLBs. This paper proposes the prepend and append schemes of in-lining the interrupt handler into the available reorder buffer space. The two schemes are implemented on a performance model of the Alpha 21264 processor built by Alpha designers at the Palo Alto Design Center (PADC), California. We compare the overhead and performance impact of handling TLB interrupts by the traditional scheme, the append in-lined scheme, and the prepend in-lined scheme. For small, medium, and large memory footprints, the overhead is quantified by comparing the number and pipeline state of instructions flushed, the energy savings, and the performance improvements. We find that lock-up free TLBs reduce the overhead of refetching and reexecuting the instructions flushed by 30-95 percent, reduce the execution time by 5-25 percent, and also reduce the energy wasted by 30-90 percent.

The Definition of Extended High-level Timed Petri Nets

Many extensions of Petri nets have been proposed to model the behaviors and time relations of embedded system, yet these models are all based on some assumptions about the behaviors of embedded systems. Especially they all do not have the actual ability to model interrupt mechanism of embedded system. A new net which is called Extended High Level Timed Petri Nets (EHLTPN) is introduced in this study. It shows how to extend High Level Petri Nets (HLPN) with time, actions and interrupt mechanism. Interruptible subnets corresponding to different interruptible resources are introduced to model the behaviors and time relations of distributed embedded real-time systems. Each interruptible subnet realizes interrupt mechanism by an Interrupt Switch Transition and a set of Resuming Transitions. We give an informal description of this new model and show how this model be formally defined. A transform rule presented shows that each subnet corresponding to an interruptible resource in EHLTPN can be transformed into a behaviorally equivalent subnet of HLTPNAT with priority. This model makes it possible to create the compact and comprehensive models for distributed embedded real-time systems.

Paracontrast and metacontrast in schizophrenia: clarifying the mechanism for visual masking deficits

Schizophrenic patients consistently demonstrate performance deficits on visual masking procedures. Visual masking can occur through two distinctly different mechanisms: interruption and integration. One highly effective way to limit the masking mechanism to interruption is to use a mask that surrounds, but does not spatially overlap, the target. These procedures are called paracontrast and metacontrast (for forward and backward masking, respectively). Despite their clear advantages for interpretation, paracontrast and metacontrast have not been used previously in schizophrenia. In the present study, we examined the reliability of the paracontrast and metacontrast procedures by administering these tasks to 103 schizophrenic patients and 49 normal control subjects. In addition, we compared the results to those from a low-energy masking condition, which is an alternative way to limit masking to interruption. Patients showed deficits on both the paracontrast and metacontrast procedures. The deficits in paracontrast and metacontrast were comparable to those seen previously with low-energy masking. These results suggest that the paracontrast/metacontrast procedure and the procedure using a low-energy mask are roughly equally sensitive to deficits in early visual processing among schizophrenic patients. These results bolster previous conclusions that schizophrenic patients show deficits on visual masking tasks even when masking on those tasks occurs entirely through the interruption mechanism.

Dynamics of fuel cell performance degradation

Dynamics of performance degradation of a PEM fuel cell operating in galvanostatic regime is investigated. Experiments enable to distinguish the three phases of cell degradation: the phase of stable operation, the phase of slow decrease of cell voltage V cell with time and the phase of V cell rapid fall. Experiments suggest that the duration of stable operation phase depends on oxygen stoichiometric ratio. To explain this we assume that (i) local degradation interrupts generation of local current and (ii) the rate of local degradation is a jump function of local current density. Dynamics of performance degradation is then determined by the degradation wave, which propagates in the along-the-channel direction towards the channel outlet. Analysis of wave properties enables to explain qualitatively the experimental dependence of cell voltage on time. The degradation of fuel cell performance may thus follow the universal scenario, which includes propagation of the degradation wave. Actual physical mechanism of local current interruption determines the time scales in this scenario.

Assessing the Soft Error Rate of Digital Architectures Devoted to Operate in Radiation Environment: A Case Studied

The effects of transient bit flips on the operation of processor based architectures is investigated through fault injection experiments performed in the hardware itself by means of the interruption mechanism. Such an approach is based on the execution, as the consequence of an interruption signal assertion, of pieces of code called CEU (Code Emulating Upsets), asynchronously downloaded in a suitable memory area. This paper focuses in the methodology followed to set-up CEU injection experiments on a digital architecture, illustrating it main steps by means of a studied case: the 80C51 microcontroller. Results obtained from automated fault injection sessions performed using the capabilities of a devoted test system, will point out the capabilities and limitations of the studied approach.

Alcoholism, hypercortisonism, fat embolism and osseous avascular necrosis. 1971.

Alcoholism, hypercortisonism, fat embolism and osseous avascular necrosis. 1971.

Development and application of the NT device driver in CNC system

The key technology of open architecture CNC systems-kernel device driver, including the interrupt mechanism, I/O subsystem, the structure of device driver and the communication between the driver and the application program, is discussed in the paper and a specific application is given at the end.

Abrupt loss of constant fusion during entrainment of ventricular tachycardia at a critical paced cycle length.

Sustained monomorphic ventricular tachycardia (VT) can be frequently entrained and interrupted with rapid pacing and the mechanism of the pacing-induced interruption is considered to be due to orthodromic block. This study focused on the incidence of VT which was interrupted at a critical cycle length and was characterized by an abrupt loss of constant fusion in the surface electrocardiogram (ECG), and the role of orthodromic block as the cause of such characteristic change and interruption of VT was analyzed. Among 45 consecutive patients with symptomatic VT, rapid pacing was performed in 43 VTs of 39 patients. The exit was mapped as the earliest site of the activation during VT and an electrode catheter was located at the site. Rapid pacing was performed at progressively shorter cycle lengths in steps of 10 msec until VT was interrupted and the timing of the orthodromic and direct capture was compared at the exit. Abrupt loss of constant fusion was observed in 25 of 39 patients (64.1%): and the loss was invariably associated with interruption of VT. When the timings of the activation of the exit were compared, which were measured from the preceding (n-1) stimulus as the time reference, the direct capture was relatively delayed compared to that of the orthodromic capture. This finding suggests that orthodromic block is the cause of the direct capture as well as the pacing-induced interruption of VT. In the remaining 13 patients (35.9%), the surface ECG showed a gradual transition into the fully paced QRS morphology. The direct capture was confirmed in the non-fused beats, but it was not necessarily associated with interruption of VT. The interval from the stimulus to the entrained electrogram at the exit showed a gradual prolongation until the exit was finally captured directly from the pacing site. The confirmation of constant fusion followed by abrupt loss in ECG can be a reliable hallmark of orthodromic block as the cause of the interruption of VT during transient entrainment at a critical paced cycle length.

Successful interrupted feeding of adult Rhipicephalus appendiculatus (Ixodidae) is accompanied by reprogramming of salivary gland protein expression.

Ixodid female ticks take one comparatively large bloodmeal which they convert to a single large egg mass and then they die. To examine the outcome of interrupted feeding, equal numbers of male and female Rhipicephalus appendiculatus adult ticks were fed on guinea pigs (host 1) for either 2, 4, or 6 days, or to engorgement (8 days). All of the fully engorged (D8) females laid a single large egg mass (80-160 mg/tick), while 85% of the day 6-fed (D6) female ticks (n = 20) each laid a small egg mass (6.1 mg/tick). None of the females that had fed for 2 or 4 days oviposited. Ninety percent (n = 20) of the day 2-fed (D2) females survived for 4 weeks after their feeding was interrupted, whereas 65% (n = 20) of the day 4-fed (D4) females survived. All of the surviving partially fed female ticks (D2 and D4) attached to a second guinea pig (host 2) and attained engorged body weights that were not significantly different from those of the control females (P < 0.05). Female ticks that engorged following interrupted feeding layed egg masses comparable to the controls, indicating that engorgement on host 2 was successful. The salivary gland protein profile of female ticks changed constantly during feeding. However, when feeding was interrupted, the protein expression pattern switched back to that of the non-parasitic state, presumably to enable the partially fed ticks to survive and reattach on the new host. This observation indicates that female ixodid ticks have a natural ability to survive and re-establish successful feeding on a new host if the first attempt at feeding is unsuccessful. Such an interrupted feeding mechanism supports the hypothesis that partially engorged ticks may play a role in tick-borne pathogen transmission.

Nerve Growth Factor Treatment Prevents the Increase in Superoxide Produced by Epidermal Growth Factor in PC12 Cells

Stimulation of pheochromocytoma (PC12) cells with the mitogen epidermal growth factor (EGF) produced a rapid and robust accumulation of intracellular reactive oxygen species (ROS), an accumulation which, in other systems, has been shown to be essential for mitogenesis. Brief pretreatment of the cells with nerve growth factor (NGF) suppressed the EGF-mediated ROS increase. EGF failed to produce elevations in ROS in a PC12 variant stably expressing a dominant-negative p21(ras) construct (PC12-N17) or in cells pretreated with the MEK inhibitor PD098059. NGF failed to suppress the increase in ROS in the PC12 variant nnr5, which lacks p140(trk) receptors. The suppression of the increase in ROS by NGF was restored in nnr5 cells stably expressing p140(trk) (nnr5-trk), but NGF failed to prevent the increase in ROS in nnr cells expressing mutant p140(trk) receptors that lack binding sites for Shc and phospholipase Cgamma. Among several inhibitors of superoxide-generating enzymes, only the lipoxygenase inhibitor, nordihydroguaiaretic acid reduced EGF-mediated ROS accumulation. The inhibitory action of NGF on ROS production was mimicked by the nitric oxide donor, sodium nitroprusside, and was blocked by an inhibitor of nitric-oxide synthetase, L-nitroarginine methyl ester. These results suggest a novel mechanism for the rapid interruption of mitogenic signaling by the neurotrophin NGF.

Performance analysis of RAID for different communication mechanism between RAID controller and string controllers

A Stochastic Petri Nets (SPN) model of the orthogonal RAID is constructed. After analyzing the performance of the system we can see that the performance of the system has the relationship with the choice of communication mechanism, which is the polling mechanism or interrupt mechanism, between the RAID controller and the string controllers. The faster the rate of the Go to Communication transition in the SPN, the higher the average utilization of the string controller, and the better the performance of RAID. The rate is larger under the polling mechanism than that under the interrupt mechanism in RAID. Thus, the polling mechanism between the RAID controller and the string controllers should be adopted to improve the performance of RAID.