The Progressive Edge Growth (PEG) algorithm is one of the most widely-used methods for constructing finite length LDPC codes. In this paper we consider the PEG algorithm together with a scheduling distribution, which specifies the order in which edges are established in the graph. The goal is to find a scheduling distribution that yields “the best” performance in terms of decoding overhead, per...

Hybrid Scheduling Problems (HSPs) contain both temporal and finite-domain variables, as well as constraints between them. A hybrid constraint over temporal and finite-domain variables often models situations where different assignments to a subset of finite-domain variables result in different bounds on temporal constraints. The insight we examine in this paper is that some temporal constraint ...

In the job shop scheduling problem (JSP), a finite set of jobs is processed on a finite set of machines. Each job is characterized by a fixed order of operations, each of which is to be processed on a specific machine for a specified duration. Each machine can process at most one job at a time and once a job initiates processing on a given machine it must complete processing uninterrupted. A sc...

In this paper, the problem of lot sizing, scheduling and delivery of several items in a two-stage supply chain over a finite planning horizon is studied. Single supplier via a flexible flow line production system (FFL), produces several items and delivers them directly to an assembly facility. Based on basic period (BP) strategy, a new mixed zero-one nonlinear programming model has been develop...

We develop algorithms for a single machine stochastic appointment sequencing and scheduling problem with waiting time, idle time, and overtime costs. This is a basic stochastic scheduling problem that has been studied in various forms by several previous authors. Applications for this problem cited previously include scheduling of surgeries in an operating room (Denton, 2007, Denton and Gupta,2...

In a packet switching system, arriving packets have variable lengths. They are segmented into fixed size cells before being switched. In packet-mode scheduling, cells from a packet should be delivered contiguously. Even though fixed-size cell scheduling has been well studied, packet-mode scheduling has more advantages: it has a lower implementation cost and higher throughput. In this paper, we ...

We study a system of several identical servers in parallel, where a routing decision must be made immediately on a job’s arrival. Jobs arrive according to a Poisson process, with their processing times following a discrete distribution with finite support. The processing time of a job is known on arrival and may be used in the routing decision. We propose a policy consisting of multi-layered ro...

In this paper we consider energy efficient scheduling in a multiuser setting where each user has a finite sized queue and there is a cost associated with holding packets (jobs) in each queue (modeling the delay constraints). The packets of each user need to be sent over a common channel. The channel qualities seen by the users are time-varying and differ across users; also, the cost incurred, i...

Scheduling algorithms in CDMA packet systems need to allocate codes and power based on channel state information and queue information. For finite queue sizes, the allocated rate should be less than or equal to the maximum rate required to clear the whole queue. This ensures that resources are not under-utilized. Although queue size and head-of-the-line packet delays have been considered in exi...

Lagrangian relaxation has been pursued as a pertinent methodology for many hard scheduling problems. From standard duality theory, the method is known to provide good-quality bounds to the performance of the optimal solutions of these problems, and in certain cases, the optimal Lagrange multipliers can function as a starting point for the construction good suboptimal solutions for the original ...