Speeding up Stochastic Dynamic Programming with Zero-Delay Convolution

We show how a technique from signal processing known as zero-delay convolution can be used to develop more efficient dynamic programming algorithms for a broad class of stochastic optimization problems. This class includes several variants of discrete stochastic shortest path, scheduling, and knapsack problems, all of which involve making a series of decisions over time that have stochastic consequences in terms of the temporal delay between successive decisions. We also correct a flaw in the original analysis of the zero-delay convolution algorithm

The complexity of generating robust resource-constrained baseline schedules.

Robust scheduling aims at the construction of a schedule that is protected against uncertain events. A stable schedule is a robust schedule that will change little when variations in the input parameters arise. Robustness can also be achieved by making the schedule makespan insensitive to variability. In this paper, we describe models for the generation of stable and insensitive baseline schedules for resource-constrained scheduling problems and present results on their complexity status. We start from a project scheduling viewpoint and derive results on machine scheduling sub-problems.Complexity; Information; Product scheduling; Robustness; sensitivity; stability;

Demand Response Driven Load Scheduling in Formal Smart Grid Framework

In this technical report, we present the current state of the research conducted during the first part of the PhD project named “Demand Response Driven Load Scheduling in Formal Smart Grid Framework”. The PhD project focuses on smart grids which employ information and communication technologies to assist the electricity production, distribution, and consumption. Designing smart grid applications is a novel challenging task that requires modeling, integrating, and validating different grid aspects in an efficient way. The project tackles such challenges by proposing an effective framework to formally describe smart grid elements along with their interactions. To validate this framework, the report concentrates on deploying efficiency in managing the electricity consumption in households which requires focusing on different impacts of demand response programs running in the smart grid to engage consumers to participate. A demand response system is considered which is connected to all households and utilizes their information to determine an effective load management strategy taking into account the grid constraints imposed by distribution system operators. The main responsibility of the demand response system is scheduling the operation of appliances of a large number of consumers in order to achieve a network-wide optimized performance. Finally, the PhD report demonstrates the simulation results, publications, courses, and dissemination activities done during this period. They are followed by envisaging future plans that will lead to completion of the PhD study

A Hierarchical Scheduling Model for Dynamic Soft-Realtime System

We present a new hierarchical approximation and scheduling approach for applications and tasks with multiple modes on a single processor. Our model allows for a temporal and spatial distribution of the feasibility problem for a variable set of tasks with non-deterministic and fluctuating costs at runtime. In case of overloads an optimal degradation strategy selects one of several application modes or even temporarily deactivates applications. Hence, transient and permanent bottlenecks can be overcome with an optimal system quality, which is dynamically decided. This paper gives the first comprehensive and complete overview of all aspects of our research, including a novel CBS concept to confine entire applications, an evaluation of our system by using a video-on-demand application, an outline for adding further resource dimension, and aspects of our protoype implementation based on RTSJ