In this paper, we analyze the performance impact of JobTracker failure in Hadoop. A JobTracker failure is a serious problem that affects the overall job processing performance. We describe the cause of failure and the system behaviors because of failed job processing in the Hadoop. On the basis of the analysis, we build a job completion time model that reflects failure effects. Our model is bas...

This paper presents an equivalence result between expected utility theory (EU) and a modified version of case-based decision theory (CBDT). To be precise, it shows that a model constructed in EU can be embedded in a CBDT model, and vice versa. CBDT, proposed and axiomatized by Gilboa and Schmeidler (1995, Case-based decision theory, Quarterly Journal of Economics 110, 605–639), is related to ca...

Steering is a challenging task, required by nearly all agents in virtual worlds. There is a large and growing number of approaches for steering, and it is becoming increasingly important to ask a fundamental question: how can we objectively compare steering algorithms? To our knowledge, there is no standard way of evaluating or comparing the quality of steering solutions. This paper presents St...

We show that suffix trees store various kinds of redundant information. We exploit these redundancies to obtain more space efficient representations. The most space efficient of our representations requires 20 bytes per input character in the worst case, and 10.1 bytes per input character on average for a collection of 42 files of different type. This is an advantage of more than 8 bytes per in...

This paper describes a methodology for validating a ground-based, hardware-in-theloop, space-robot simulation facility. This facility, called ‘‘SPDM task verification facility,’’ is being developed by the Canadian Space Agency for the purpose of verifying the contact dynamics performance of the special purpose dexterous manipulator (SPDM) performing various maintenance tasks on the Internationa...

The Chord protocol is the best known example of implementation of logarithmic complexity routing for structured peer-to-peer networks. Its routing algorithm, however, does not provide an optimal trade-off between resources exploited (the size of the ‘finger table’) and performance (the average or worst-case number of hops to reach destination). Cordasco et al. showed that a finger table based o...

Introduction: Vitamin D deficiency and rickets continue to be health problems in developing countries and most of the infants with congenital rickets may present with hypocalcemic seizure.   Case Report In this article, the report on four infants who presented with hypocalcemic seizures but subsequently were found to have congenital rickets is presented. All of them had hypocalcaemia and low le...

This article presents a new digital image compression scheme which exploits a human visual system property—namely, recognizing images by their regions—to achieve high compression ratios. It also assigns a variable bit count to each image region that is proportional to the amount of information it conveys to the viewer. The new scheme copes with image nonstationarity by adaptively segmenting the...

Mutation testing is an effective but costly testing technique. Several studies have observed that some mutants can be redundant and therefore removed without affecting its effectiveness. Similarly, some mutants may be more effective than others in guiding the tester on the creation of high-quality test cases. Based on these findings, we present an assessment of C++ class mutation operators by c...

A k-dominating set of a graph G is a subset D of the vertices of G such that every vertex of G is either in D or at distance at most k from a vertex in D. It is of interest to find k-dominating sets of small cardinality. In this paper we consider simple randomised greedy algorithms for finding small k-dominating sets of regular graphs. We analyse the average-case performance of the most efficie...