Thread Scheduling Mechanisms for Multiple-Context Parallel Processors

Scheduling tasks to efficiently use the available processor resources is crucial to minimizing the runtime of applications on shared-memory parallel processors. One factor that contributes to poor processor utilization is the idle time caused by long latency operations, such as remote memory references or processor synchronization operations. One way of tolerating this latency is to use a processor with multiple hardware contexts that can rapidly switch to executing another thread of computation whenever a long latency operation occurs, thus increasing processor utilization by overlapping computation with communication. Although multiple contexts are effective for tolerating latency, this effectiveness can be limited by memory and network bandwidth, by cache interference effects among the multiple contexts, and by critical tasks sharing processor resources with less critical tasks. This thesis presents techniques that increase the effectiveness of multiple contexts by intelligently scheduling threads to make more efficient use of processor pipeline, bandwidth, and cache resources. This thesis proposes thread prioritization as a fundamental mechanism for directing the thread schedule on a multiple-context processor. A priority is assigned to each thread either statically or dynamically and is used by the thread scheduler to decide which threads to load in the contexts, and to decide which context to switch to on a context switch. We develop a multiple-context model that integrates both cache and network effects, and shows how thread prioritization can both maintain high processor utilization, and limit increases in critical path runtime caused by multithreading. The model also shows that in order to be effective in bandwidth limited applications, thread prioritization must be extended to prioritize memory requests. We show how simple hardware can prioritize the running of threads in the multiple contexts, and the issuing of requests to both the local memory and the network. Simulation experiments show how thread prioritization is used in a variety of applications. Thread prioritization can improve the performance of synchronization primitives by minimizing the number of processor cycles wasted in spinning and devoting more cycles to critical threads. Thread prioritization can be used in combination with other techniques to improve cache performance and minimize cache interference between different working sets in the cache. For applications that are critical path limited, thread prioritization can improve performance by allowing processor resources to be devoted preferentially to critical threads. These experimental results show that thread prioritization is a mechanism that can be used to implement a wide range of scheduling policies.

Optimal Methodology for Synchronized Scheduling of Parallel Station Assembly with Air Transportation

We present an optimal methodology for synchronized scheduling of production assembly with air transportation to achieve accurate delivery with minimized cost in consumer electronics supply chain (CESC). This problem was motivated by a major PC manufacturer in consumer electronics industry, where it is required to schedule the delivery requirements to meet the customer needs in different parts of South East Asia. The overall problem is decomposed into two sub-problems which consist of an air transportation allocation problem and an assembly scheduling problem. The air transportation allocation problem is formulated as a Linear Programming Problem with earliness tardiness penalties for job orders. For the assembly scheduling problem, it is basically required to sequence the job orders on the assembly stations to minimize their waiting times before they are shipped by flights to their destinations. Hence the second sub-problem is modelled as a scheduling problem with earliness penalties. The earliness penalties are assumed to be independent of the job orders.

Planning and Scheduling Decisions in Supply Chains with Multiple Supply Modes: An Integrated Approach

We address the problem of jointly determining shipment planning and scheduling decisions with the presence of multiple shipment modes. We consider long lead time, less expensive sea shipment mode, and short lead time but expensive air shipment modes. Existing research on multiple shipment modes largely address the short term scheduling decisions only. Motivated by an industrial problem where planning decisions are independent of the scheduling decisions, we investigate the benefits of integrating the two sets of decisions. We develop sequence of mathematical models to address the planning and scheduling decisions. Preliminary computational results indicate improved performance of the integrated approach over some of the existing policies used in real-life situations.

A Gain Scheduling Model Predictive Controller for Blood Glucose Control in Type 1 Diabetes

This paper presents a control strategy for blood glucose(BG) level regulation in type 1 diabetic patients. To design the controller, model-based predictive control scheme has been applied to a newly developed diabetic patient model. The controller is provided with a feedforward loop to improve meal compensation, a gain-scheduling scheme to account for different BG levels, and an asymmetric cost function to reduce hypoglycemic risk. A simulation environment that has been approved for testing of artificial pancreas control algorithms has been used to test the controller. The simulation results show a good controller performance in fasting conditions and meal disturbance rejection, and robustness against model–patient mismatch and errors in meal estimation

At the centre of the Bologna process : do European universities train their students to face knowledge based societies?. 'En el centro del proceso de Bolonia: ¿entrenan las universidades europeas a sus estudiantes para enfrentarse a sociedades basadas en el conocimiento?'.

Resumen tomado de la publicación. Monográfico con el título: El proceso de Bolonia : dinámicas y desafíos de la enseñanza superior en Europa a comienzos de una nueva época

Oi! Get off our train.

En sus sueños, el niño y su perro de juguete, inician un viaje a lo largo del mundo en un tren de vapor. En el recorrido, van subiendo al tren distintos animales que están en vías de extinción.

The train ride.

Una niña y su madre van en el tren desde la ciudad al campo para visitar a la abuela. Un texto que rima, establece el tono sobre todas las cosas que se pueden ver desde el tren. A la pregunta: qué veo, el cambio de página muestra un nuevo panorama: una yegua y su potro, un tractor de color rojo brillante, unos gansos, un globo de aire caliente, la respuesta y el estribillo :eso es lo que veo. Por fin la niña y su madre llegan a su destino. Recurso para la enseñanza de la lectura. Es el inicio de una reflexión sobre los textos y sus significados. Los niños pueden aprender a dividir una palabra en sus partes principales y crear nuevas palabras por analogía con las palabras que conocen, o para sugerir otras palabras. Para la lectura en grupos, individual o en parejas.

The train ride.

Una niña y su madre van en el tren desde la ciudad al campo para visitar a la abuela. Un texto que rima, establece el tono sobre todas las cosas que se pueden ver desde el tren. A la pregunta: qué veo, el cambio de página muestra un nuevo panorama: una yegua y su potro, un tractor de color rojo brillante, unos gansos, un globo de aire caliente, la respuesta y el estribillo :eso es lo que veo. Por fin la niña y su madre llegan a su destino. Recurso para la enseñanza de la lectura. Es el inicio de una reflexión sobre los textos y sus significados. Los niños pueden aprender a dividir una palabra en sus partes principales y crear nuevas palabras por analogía con las palabras que conocen, o para sugerir otras palabras. Para la lectura en grupos, individual o en parejas.

A technique to train auditory and visual memory for speech patterns in young hearing-impaired children

This paper details a technique for training auditory memory for length of speech sounds in preschool children with a profound hearing loss.

Use of the storage oscilloscope to train deaf children to convey meaning in sentences through intonation control

This paper is a review of a study to determine if profoundly deaf adolescents could be trained in intonation control in using a two-channel storage oscilloscope.

Use of the storage oscilloscope to train deaf children to convey meaning in sentences through intonation control

This paper is a review of a study to determine if profoundly deaf adolescents could be trained in intonation control in using a two-channel storage oscilloscope.

A survey of CTA train noise

This paper discusses a study of CTA commuter trains in Chicago and whether Chicago is in need of regulations of standards for noise emitted by CTA trains.

A Multi Bearer Adaptable Communication Demonstrator for Train-to-Ground IP Communication to Increase Resilience

Preprint version