On The Computational Complexity Of Stochastic Scheduling Problems

In this paper we consider stochastic scheduling models where all relevant data (like processing times, release dates, due dates, etc.) are independent random variables, exponentially distributed. We are interested in the computational complexity of determining optimal policies for these stochastic scheduling models. We give a number of examples of models in which the optimal policies can be determined by polynomial time algorithms while the deterministic counterparts of these models are NP-complete. We also give some examples of stochastic scheduling models for which there exists no polynomial time algorithm if P is not equal NP. (Author).

This volume contains the proceedings of an Advanced Study and Re search Institute on Theoretical Approaches to Scheduling Problems. The Institute was held in Durham, England, from July 6 to July 17, 1981. It was attended by 91 participants from fifteen different countries. The format of the Institute was somewhat unusual. The first eight of the ten available days were devoted to an Advanced Study Insti tute, with lectures on the state of the art with respect to deter ministic and stochastic scheduling models and on the interface between these two approaches. The last two days were occupied by an Advanced Research Institute, where recent results and promising directions for future research, especially in the interface area, were discussed. Altogether, 37 lectures were delivered by 24 lecturers. They have all contributed to these proceedings, the first part of which deals with the Advanced Study Institute and the second part of which covers the Advanced Research Institute. Each part is preceded by an introduction, written by the editors. While confessing to a natural bias as organizers, we believe that the Institute has been a rewarding and enjoyable event for everyone concerned. We are very grateful to all those who have contributed to its realization.

The book contains algorithms for classical and complex scheduling problems, new results on scheduling problems arising in flexible manufacturing, and an extensive overview of the area of scheduling. The methods used to solve these problems include: linear programming, dynamic programming, branch-and-bound algorithms, and local search heuristics. In the third edition of the book the complexity status of the different classes of scheduling problems has been updated. New polynomial algorithms for single machine problems with release times and constant processing times have been added.

This is a comprehensive study of various time-dependent scheduling problems in single-, parallel- and dedicated-machine environments. In addition to complexity issues and exact or heuristic algorithms which are typically presented in scheduling books, the author also includes more advanced topics such as matrix methods in time-dependent scheduling, time-dependent scheduling with two criteria and time-dependent two-agent scheduling. The reader should be familiar with the basic notions of calculus, discrete mathematics and combinatorial optimization theory, while the book offers introductory material on theory of algorithms, NP-complete problems, and the basics of scheduling theory. The author includes numerous examples, figures and tables, he presents different classes of algorithms using pseudocode, he completes all chapters with extensive bibliographies, and he closes the book with comprehensive symbol and subject indexes. The previous edition of the book focused on computational complexity of time-dependent scheduling problems. In this edition, the author concentrates on models of time-dependent job processing times and algorithms for solving time-dependent scheduling problems. The book is suitable for researchers working on scheduling, problem complexity, optimization, heuristics and local search algorithms.

Researchers in management, industrial engineering, operations, and computer science have intensely studied scheduling for more than 50 years, resulting in an astounding body of knowledge in this field. Handbook of Scheduling: Algorithms, Models, and Performance Analysis, the first handbook on scheduling, provides full coverage of the most recent and advanced topics on the subject. It assembles researchers from all relevant disciplines in order to facilitate cross-fertilization and create new scheduling insights. The book comprises six major parts, each of which breaks down into smaller chapters: · Part I introduces materials and notation, with tutorials on complexity theory and algorithms for the minimization of makespan, total completion time, dual objectives, maximum lateness, the number of late jobs, and total tardiness. · Part II is devoted to classical scheduling problems. · Part III explores scheduling models that originate in computer science, operations research, and management science. · Part IV examines scheduling problems that arise in real-time systems, focusing on meeting hard deadline constraints while maximizing machine utilization. · Part V discusses stochastic scheduling and queueing networks, highlighting jobs that are not deterministic. · Part VI covers applications, discussing scheduling problems in airline, process, and transportation industries, as well as in hospitals and educational institutions.

The principal theme of this book is combinatorial scheduling. All coverage is confined to deterministic results and includes conventional models involving single and multiple processors as well as ones of the classic flow and job shop-like variety. In addition, the book discusses workforce staffing models, timetabling problems, the classroom assignment model, and even problems related to traversals in graphs. The author has included understandable descriptions of computational algorithms, demonstrations of algorithms and theorems with sample problems, and substantial lists of end-of-chapter exercises which span from relatively routine manipulation to increasingly challenging, possibly even open problems. An entire chapter is included on background material. Covered are basic concepts in computational complexity, the theory of graphs, and partial enumeration. The book should appeal to students and researchers in a host of areas including industrial engineering, operations research, computer science, and discrete mathematics.

New and classical results in computational complexity, including interactive proofs, PCP, derandomization, and quantum computation. Ideal for graduate students.