Exploring heterogeneity of unreliable machines for p2p backup

P2P architecture is a viable option for enterprise backup. In contrast to dedicated backup servers, nowadays a standard solution, making backups directly on organization's workstations should be cheaper (as existing hardware is used), more efficient (as there is no single bottleneck server) and more reliable (as the machines are geographically dispersed). We present the architecture of a p2p backup system that uses pairwise replication contracts between a data owner and a replicator. In contrast to standard p2p storage systems using directly a DHT, the contracts allow our system to optimize replicas' placement depending on a specific optimization strategy, and so to take advantage of the heterogeneity of the machines and the network. Such optimization is particularly appealing in the context of backup: replicas can be geographically dispersed, the load sent over the network can be minimized, or the optimization goal can be to minimize the backup/restore time. However, managing the contracts, keeping them consistent and adjusting them in response to dynamically changing environment is challenging. We built a scientific prototype and ran the experiments on 150 workstations in the university's computer laboratories and, separately, on 50 PlanetLab nodes. We found out that the main factor affecting the quality of the system is the availability of the machines. Yet, our main conclusion is that it is possible to build an efficient and reliable backup system on highly unreliable machines (our computers had just 13% average availability)

A model for FMS of unreliable machines

Fulltext link (Conference paper): http://www.wseas.us/e-library/conferences/athens2000/Papers2000/170.pdfDocument Type: ArticleThis paper studies Markovian queueing model for flexible manufacturing system. The manufacturing system consists of multiple unreliable machines. Hedging point policy is applied to the system as production control. We model the machine states and inventory levels of the system as a multi-server queueing system. Fast numerical algorithm is presented to solve the steady state probability distribution of the system. Using the probability distribution, the system performance and the effect of machine reliability and maintainability can be evaluated.link_to_subscribed_fulltex

Rescheduling frequency in an FMS with uncertain processing times and unreliable machines

Cataloged from PDF version of article.This paper studies the scheduling/rescheduling problem in a multi-resource FMS environment. Several reactive scheduling policies are proposed to address the effects of machine breakdowns and processing time variations. Both off-line and on-line scheduling methods are tested under a variety of experimental conditions. The performance of the system is measured for mean tardiness and makespan criteria. The relationships between scheduling frequency and other scheduling factors are investigated. The results indicated that a periodic response with an appropriate period length would be sufficient to cope with interruptions. It was also observed that machine breakdowns have more significant impact on the system performance than processing time variations. In addition, dispatching rules were found to be more robust to interruptions than the optimum-seeking off-line scheduling algorithm. A comprehensive bibliography is also included in the paper

Diffusion approximations of transfer lines with unreliable machines and finite storage elements

"March, 1982"Bibliography: p. [4-5]"N00014-77-C-0532" "ET-76-A01-2295"David A. Castanon, Bernard C. Levy, Stanley B. Gershwin

Diffusion approximations for three-stage transfer lines with unreliable machines and finite buffers

"August, 1982."Bibliography: leaf [2]by David A. Castanon, Bernard C. Levy, Stanley B. Gershwin

Functional properties of throughput in tandem lines with unreliable servers and finite buffers

optimization;queueing theory;production

The rise, development and internationalization of Japan's motor industry : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Geography at Massey University

The rise of Japan's motor industry to world prominence has been one of the most spectacular developments of modern times and has come to epitomize Japan's 'economic miracle' in the postwar era. The industry's phenomenal growth was the result of various factors. During its infant and developing phases these included: a legacy in terms of industrial expertise from before the War; a much improved labour relations climate; and the favourable economic conditions that prevailed both at home and abroad that provided the framework for an era of high-speed growth. The most significant factor though, was the support given by the government which considered the industry as economically 'strategic' and 'nurtured' it to growth — along with many of its supporting industries — with a wide range of industrial policies. Notwithstanding the contribution of these factors, however, the industry showed a remarkable resourcefulness and creativity of its own. Borrowing engineering and management techniques from abroad such as Quality Control, and experimenting with new indigenous concepts such as Just-in-Time, the industry was able to dramatically raise the quality of its products and its levels of productivity. Based on these strengths the Japanese automakers became, during the 1970s, major exporters of motor vehicles and were able to capture ever larger shares of foreign markets. In recent years, however, confronted with increased international trade friction, the erection of trade barriers in its major foreign markets, and the rising value of the yen, the industry has inceasingly sought to move operations abroad. These moves to overseas locations are on such an unprecedented scale that they are contributing to create a new international geography of motor vehicle production