Usually, a proof of a theorem contains more knowledge than the mere fact that the theorem is true. For instance, to prove that a graph is Hamiltonian it suffices to exhibit a Hamiltonian tour in it; however, this seems to contain more knowledge than the single bit Hamiltonian/non-Hamiltonian.In this paper a computational complexity theory of the “knowledge” contained in a proof is developed. Zero-knowledge proofs are defined as those proofs that convey no additional knowledge other than the correctness of the proposition in question. Examples of zero-knowledge proof systems are given for the languages of quadratic residuosity and 'quadratic nonresiduosity. These are the first examples of zero-knowledge proofs for languages not known to be efficiently recognizable.

/pdf/the-knowledge-complexity-of-interactive-proof-systems-31apre0ecf.pdf

The knowledge complexity of interactive proof-systems

The high computational complexity required for performing an exact schedulability analysis of fixed priority systems has led the research community to investigate new feasibility tests which are less complex than exact tests, but still provide a reasonable performance in terms of acceptance ratio. The performance of a test is typically evaluated by generating a huge number of synthetic task sets and then computing the fraction of those that pass the test with respect to the total number of feasible ones. The resulting ratio, however, depends on the metrics used for evaluating the performance and on the method for generating random task parameters. In particular, an important factor that affects the overall result of the simulation is the probability density function of the random variables used to generate the task set parameters. In this paper we discuss and compare three different metrics that can be used for evaluating the performance of schedulability tests. Then, we investigate how the random generation procedure can bias the simulation results of some specific scheduling algorithm. Finally, we present an efficient method for generating task sets with uniform distribution in a given space, and show how some intuitive solutions typically used for task set generation can bias the simulation results.

/pdf/measuring-the-performance-of-schedulability-tests-yr1og35xbk.pdf

Measuring the Performance of Schedulability Tests

This book provides the most basic problems, concepts, and well-established results from the topological structure and analysis of interconnection networks in the graph-theoretic language. It covers the basic principles and methods of network design, several well-known networks such as hypercubes, de Bruijn digraphs, Kautz digraphs, double loop, and other networks, and the newest parameters to measure performance of fault-tolerant networks such as Menger number, Rabin number, fault-tolerant diameter, wide-diameter, restricted connectivity, and (l,w)-dominating number. Audience: The book is suitable for those readers who are working on or intend to start research in design analysis of the topological structure of interconnection networks, particularly undergraduates and postgraduates specializing in computer science and applied mathematics.

Topological Structure and Analysis of Interconnection Networks

The paper shows that characterizing the causal relationship between significant events is an important but non-trivial aspect for understanding the behavior of distributed programs. An introduction to the notion of causality and its relation to logical time is given; some fundamental results concerning the characterization of causality are presented. Recent work on the detection of causal relationships in distributed computations is surveyed. The issue of observing distributed computations in a causally consistent way and the basic problems of detecting global predicates are discussed. To illustrate the major difficulties, some typical monitoring and debugging approaches are assessed, and it is demonstrated how their feasibility is severely limited by the fundamental problem to master the complexity of causal relationships.

/pdf/detecting-causal-relationships-in-distributed-computations-2v03y969vq.pdf

Detecting causal relationships in distributed computations: in search of the holy grail

A senior undergraduate or graduate level computer science textbook on algorithm design for distributed computer systems.

/pdf/an-introduction-to-distributed-algorithms-2scptn142v.pdf

An Introduction to Distributed Algorithms

k -Arbiter: a safe and general scheme for h -out of- k mutual exclusion

Rate monotonic and deadline monotonic scheduling are commonly used for periodic real-time task systems. This paper discusses a feasibility decision for a given real-time task system when the system is scheduled by rate monotonic and deadline monotonic scheduling. The time complexity of existing feasibility decision algorithms depends on both the number of tasks and maximum periods or deadlines when the periods and deadlines are integers. This paper presents a new necessary and sufficient condition for a given task system to be feasible and proposes a new feasibility decision algorithm based on that condition. The time complexity of this algorithm depends solely on the number of tasks. This condition can also be applied as a sufficient condition for a task system using priority inheritance protocols to be feasible with rate monotonic and deadline monotonic scheduling.

A Feasibility Decision Algorithm for Rate Monotonic andDeadline Monotonic Scheduling

This paper describes algorithms for a distributed program debugger based on a replay technique. Halting at breakpoints and selective tracing are its fundamental features. In distributed systems, a given breakpoint or trace condition does not uniquely define the global state at which to halt or trace, because of the asynchrony of processes and communications. This paper therefore proposes the “first” global state Inf(P) to be the best global state at which to halt or trace, for a given condition P. Two kinds of global conditions related to plural processes, Conjunctive Predicates and Disjunctive Predicates, are considered. The authors present an algorithm that halts processes at Inf(P) for a given Conjunctive Predicate P. It is also shown that, for a Disjunctive Predicate P, it is impossible to halt at Inf(P), but possible to halt at some state which satisfies P. An algorithm is also provided for selective tracing when a Conjunctive or Disjunctive Predicate selection condition is given.

Global conditions in debugging distributed programs

Many works have been done for secure computation of functions. Most of them assume computation on computers. The protocols are difficult for the people who has no knowledge on cryptography. Therefore, secure computation using cards was considered. Since nothing other than the cards are used, the protocols are easy to understand for the people who has no knowledge on cryptography. This paper presents a card-based protocol that generates a random hidden permutation. This problem is applicable to a case when players exchange gifts. The protocol must not output a permutation with a fixed point, which means that every player does not receive the gift he/she prepared. Ishikawa et. al proposed a protocol with two-color cards using random shuffles and a proof of having no fixed points. However, the success probability of the protocol is not so high. Therefore, more efficient random permutation protocol is required. In this paper, we use cyclic shuffles in addition to the random shuffles to lower the possibility of fixed points. We show the success probability of obtaining a permutation without fixed points by our protocol is better than the one by the existing protocol.

Yoshifumi Manabe

Papers

k -Arbiter: a safe and general scheme for h -out of- k mutual exclusion

A Feasibility Decision Algorithm for Rate Monotonic andDeadline Monotonic Scheduling

Global conditions in debugging distributed programs

A More Efficient Card-Based Protocol for Generating a Random Permutation without Fixed Points

Global conditions in debugging distributed programs