Priority Rules for Multi‐Task Due‐Date Scheduling under Varying Processing Costs

This paper presents scheduling algorithms for procrastinators, where the speed that a procrastinator executes a job increases as the due date approaches. We give optimal off-line scheduling policies for linearly increasing speed functions. We then explain the computational/numerical issues involved in implementing this policy. We next explore the online setting, showing that there exist adversaries that force any online scheduling policy to miss due dates. This impossibility result motivates the problem of minimizing the maximum interval stretch of any job; the interval stretch of a job is the job's flow time divided by the job's due date minus release time. We show that several common scheduling strategies, including the "hit-the-highest-nail" strategy beloved by procrastinators, have arbitrarily large maximum interval stretch. Then we give the "thrashing" scheduling policy and show that it is a \Theta(1) approximation algorithm for the maximum interval stretch.

Adaptive policies for multi-mode project scheduling under uncertainty

Cloud computing and big data: Technologies and applications

We study single-machine bicriteria scheduling problems with position-dependent weights. Due date costs and penalty costs can affect the decision-maker’s profit. Therefore, how to optimize the benefits and balance of these costs for decision-makers is the focus of this research. This paper discusses three models: weighted-sum scheduling problem, constrained scheduling problem, Pareto scheduling problem. It analyzes the properties of bicriteria schedule, determines the optimal due dates (usually referred to as different due dates: DIF), and gives the corresponding polynomial solvable algorithms.

A common task for all deterministic multithreading (DMT) systems is to enforce synchronization determinism. However, synchronization determinism has not been the focus of existing DMT research. Instead, most DMT systems focused on how to order data races remained after synchronization determinism is enforced. Consequently, existing scheduling policies for synchronization determinism all have limitations. They may either require performance annotations to achieve good performance or fail to provide schedule stability.

Constant Job-Allowance Policies for Appointment Scheduling: Asymptotic Optimality and Numerical Analysis

Optimal radio access technology selection on heterogeneous networks

The OS scheduler's memory and runtime overheads form crucial design constraints for embedded systems implemented on low-cost hardware platforms. Table-driven scheduling can provide a high level of schedulability; however, it also consumes significant amounts of memory. By contrast, effective non-preemptive scheduling policies, such as the non-work-conserving Critical-Window EDF (CW-EDF), have low memory usage, but substantial runtime overheads. This paper aims to achieve efficient and effective non-preemptive scheduling by using a First-In-First-Out (FIFO) scheduling policy combined with a novel offset tuning technique. This technique enables the FIFO policy to reproduce a given feasible schedule, such as that followed by CW-EDF, resulting in a high level of schedulability, combined with comparatively low runtime overheads. Further, by using a small number of offsets per task, memory overheads are also tightly constrained. The proposed solution is evaluated in terms of runtime overhead, memory consumption, and schedulability ratio, using a prototype implementation on an Arduino board. This shows that FIFO with offset tuning can match the schedulability ratio of CW-EDF, while typically exhibiting lower scheduling overheads and memory consumption than the state-of-the-art Offline Equivalence technique, which is based on Non-Preemptive Fixed Priority (NP-FP) scheduling.

An optimal procedure for minimizing total weighted resource tardiness penalty costs in the resource-constrained project scheduling problem

V-shape property for optimal schedules with monotone penalty functions

The problem of off-line inspection is of both practical and theoretical interest. It has been the subject of research in somewhat simplistic scenarios. In this paper, the theoretical coverage of this problem is extended to include inspection errors. In particular, a process which is subject to random failures that sequentially produces a batch of units is investigated. After the batch is complete, off-line inspections are performed. In the proposed model it is these inspections that are subject to errors. The optimal inspection policy, i.e., which units should be inspected and the inspection order so as to minimize the expected number of inspections, is determined. The considered objective function is to find the point at which the machine fails with a given confidence level. The optimal policy is found by a dynamic programming algorithm and four different heuristic policies are investigated. An extensive computational study that examines the behavior of both the optimal and heuristic policies is presented. In particular, the effect of the model parameters on the behavior of the optimal policy is analyzed. The heuristic policies are computationally studied with the goal of comparing their quality to the optimal solution, and also to compare the heuristics themselves.

Optimal and Near Optimal Control of a Two-Part-Type Stochastic Manufacturing System with Dynamic Setups

Leadtime uncertainty occurs in both manufacturing and distribution systems and can cause difficult coordination problems. We analyze a simple three-location, two-level distribution-type system with stochastic leadtimes with the objective of determining planned leadtimes which minimize the sum of expected inventory-holding and tardiness costs. In a manufacturing context, the system can be viewed as one in which common processing or procurement is done first, whereupon another manufacturing stage differentiates this common product. Within a distribution framework, the system is one in which material is transported to a central facility (such as a regional warehouse) and subsequently transported to smaller local distributors or retailers. We investigate two heuristic policies which are simple adjustments to optimal solutions for serial systems resulting from a decoupling of the distribution network. We also report computational experience which indicates that the optimal “location” and quantity of safety time depends largely upon the relationship among the due dates and average leadtimes for the final stages of processing or delivery.

This study applies permutation and combination techniques to optimize single machine job scheduling with precedence constraints and due dates. An R-based model was used to generate and evaluate all feasible job sequences, identifying the one that minimizes total completion time and penalty costs. Compared to traditional heuristics like SPT and EDD, the exhaustive combinatorial approach proved more effective in complex scheduling scenarios. The results highlight a data-driven method for improving scheduling efficiency, with practical relevance to manufacturing and project management.

Streaming media applications represent an important class of applications for embedded systems. Recent advances in design-space exploration of architectures for such applications have pointed towards the suitability of Multiprocessor System on Chip (SoC) solutions. Multiprocessor SoCs not only offer higher performance, but can also lead to solutions which are cheaper cost wise. A typical synthesis methodology for such architectures would require a validation stage at the end of final system integration. The wide availability of cheap and large FPGA devices, advances in automatic synthesis from VHDL/Verilog and abundance of high performance computing platforms enables the design of a generic validation system for such Multiprocessor SoCs.In this paper we present the design and implementation of Srijan Multiprocessor Prototyping System (SMPS). SMPS is a system for rapid prototyping and validation of single chip application specific multiprocessor systems. The individual computing elements are RISC processors, coprocessors which lie in the processor pipeline, and ASICs which connect directly to system bus. The system is a tightly coupled multiprocessor with shared memory and shared address space. A Real-time Operating System (RTOS) provides task scheduling and access to shared resources. The system is presented as a parameterized VHDL based on the open source Sparc~V8 compliant LEON processor and a homegrown light-weight RTOS, RtKer-MP. The entire VHDL is configurable using a GUI, has support for cache coherency, choice of arbitration policy and easy integration of custom processing engines. RtKer-MP allows for a pluggable scheduler, dynamic and static scheduling policies, static and dynamic task migrations domains and variable interruption frequencies for separate processors. The pluggable scheduler interface allows for quick exploration of various scheduling policies for a feedback to the estimation systems.