Compositional Real-Time Scheduling Framework

Our goal is to develop a compositional real-time scheduling framework so that global (system-level) timing properties can be established by composing independently (specified and) analyzed local (component-level) timing properties. The two essential problems in developing such a framework are (1) to abstract the collective real-time requirements of a component as a single real-time requirement and (2) to compose the component demand abstraction results into the system-level real-time requirement. In our earlier work, we addressed the problems using the Liu and Layland periodic model. In this paper, we address the problems using another well-known model, a bounded-delay resource partition model, as a solution model to the problems. To extend our framework to this model, we develop an exact feasibility condition for a set of bounded-delay tasks over a bounded-delay resource partition. In addition, we present simulation results to evaluate the overheads that the component demand abstraction results incur in terms of utilization increase. We also present new utilization bound results on a bounded-delay resource model

SCUBA DIVING FIN TYPES AND CHARACTERISTICS OF DIVER'S PROPULSIVE MOTION

The purpose of this study was to analyze quantitative evaluation of propulsive motion as different fin types and degree of skill that affected motion. Three skilled dive masters and three unskilled sUbjects participated in the study. The types of fin are paddle style and propller style which have different functional systems for propulsion each other. Two video cameras (Panasonic 0-5100, frame rate: 60 Hz) are used for motion analysis, and two load cells are used for measuring propulsion force. The measuring system for propulsion force was designed to acquire the pulling force. Matlab (Mathwork, Inc.) was used for separating each direction force and calculate the impulse. Kwon3D (Visol, Inc) was used to analyze the fin kick motion. Digitizing points were hip, knee and ankle joint. The subjects were tied with a rope but they could move on all direction a litte bit. Three-way ANOVA was used for analyzing significance of difference between groups, stroke rates (30-60-maximun stroke/min) and fin-types. The results of this work indicate that stroke rate was controlled by the range of knee angle, and the adequate fin style was different according to the diVing skill

Periodic Resource Model for Compositional Real-Time Guarantees

We address the problem of providing compositional hard real-time guarantees in a hierarchy of schedulers. We first propose a resource model to characterize a periodic resource allocation and present exact schedulability conditions for our proposed resource model under the EDF and RM algorithms. Using the exact schedulability conditions, we then provide methods to abstract the timing requirements that a set of periodic tasks demands under the EDF and RM algorithms as a single periodic task. With these abstraction methods, for a hierarchy of schedulers, we introduce a composition method that derives the timing requirements of a parent scheduler from the timing requirements of its child schedulers in a compositional manner such that the timing requirement of the parent scheduler is satisfied, if and only if, the timing requirements of its child schedulers are satisfied

Convex optimization framework for intermediate deadline assignment in soft and hard real-time distributed systems

It is generally challenging to determine end-to-end delays of applications for maximizing the aggregate system utility subject to timing constraints. Many practical approaches suggest the use of intermediate deadline of tasks in order to control and upper-bound their end-to-end delays. This paper proposes a unified framework for different time-sensitive, global optimization problems, and solves them in a distributed manner using Lagrangian duality. The framework uses global viewpoints to assign intermediate deadlines, taking resource contention among tasks into consideration. For soft real-time tasks, the proposed framework effectively addresses the deadline assignment problem while maximizing the aggregate quality of service. For hard real-time tasks, we show that existing heuristic solutions to the deadline assignment problem can be incorporated into the proposed framework, enriching their mathematical interpretation

THE EFFECT OF MUSCLE IMBALANCE ON MOTION OF SQUAT

INTRODUCTION: Some authors (Ann 2005) have suggested that muscle imbalance between antagonist and agonist, and deficits can have a negative influence on functional ability and thus be a cause of musculoskeletal injury. The primary purpose of this research was to understand and investigate the motional and muscle activity characteristics, of the overhead and back squat, considering the participants’ muscle imbalance

Compositional Schedulability Analysis of Hierarchical Real-Time Systems

Embedded systems are complex as a whole but consist of smaller independent modules interacting with each other. This structure makes them amenable to compositional design. Real-time embedded systems consist of realtime workloads having deadlines. Compositional design of such systems can be done using real-time components arranged in a scheduling hierarchy. Each component consists of some real-time workload and a scheduling policy for the workload. To simplify schedulability analysis for such systems, analysis should be done compositionally using interfaces that abstract timing requirement of components. To facilitate analysis of dynamically changing systems, the framework should also support incremental analysis. In this paper, we overview our approach to compositional and incremental schedulability analysis of hierarchical real-time systems. We describe a compositional analysis technique that abstracts resource requirement of components using periodic resource models. To support incremental analysis and resource bandwidth minimization, we describe an extension to this interface model. Each extended interface consists of multiple periodic resource models for different periods. This allows the selection of a periodic model that can schedule the system using minimum bandwidth. We also account for context switch overhead of components in these extended interfaces. We then describe an associative composition technique for such interfaces, that supports incremental analysis