A hardware-software design framework for distributed cellular computing

In this article, we describe a novel hardware-software design framework for prototyping cellular architectures in hardware. Based on an extensible platform of about 200 FPGAs, configured as a networked structure of processors, the hardware part of this computing framework is backed by an extensible library of software components that provides primitives for efficient inter-processor communication and distributed computation. This dual software-hardware approach allows a very quick exploration of different ways to solve computational problems using bio-inspired techniques. To demonstrate the validity of the method, we present an example of how a traditional parallel system such as a cellular automaton can be modeled and run with this perspective. In addition, we also show that the flexibility of our approach allows not only cellular automata but any computation to be easily implemented on a cellular substrate

SOS: An Object-Oriented Operating System ―- Assessment and Perspectives

International audienceSOS (SOMIW Operating System) is the result of a four-year effort at INRIA to define an object-oriented operating system. SOS provides support for arbitrary, user-defrned, typed objects. The system implements object migration; this mechanism is generic, but can be tailored to specific object semantics thanks to the prerequisite and upcall concepts. SOS also supports Fragmented Objects (FOs), i.e. objects the representation of which spreads across multiple address spaces. Fragments of a single FO are objects that enjoy mutual communication privileges. A fragment acts as a proxy, i.e. a local interface to the FO. All the other mechanisms of SOS are built upon these basic abstractions. Thanks to prerequisites, migration of data may cause the migration and dynamic type-checking and linking of the corresponding code. A distributed object manager, an object storage service, a naming service, as well as a protocol toolbox and some applications, have been built as FOs. This paper gives a detailed account of the architecture and design decisions of the SOS prototype on UNIX. rùy'e examine both good decisions and problems. The basic good decision is our simple object model, and its ability to map user-defrned semantics (policy decisions) on system-implemented mechanisms. The most important problem is the dynamic nature of Fragmented Objects, and inadequate support for them

Evaluation of Oil-Palm Fungal Disease Infestation with Canopy Hyperspectral Reflectance Data

Fungal disease detection in perennial crops is a major issue in estate management and production. However, nowadays such diagnostics are long and difficult when only made from visual symptom observation, and very expensive and damaging when based on root or stem tissue chemical analysis. As an alternative, we propose in this study to evaluate the potential of hyperspectral reflectance data to help detecting the disease efficiently without destruction of tissues. This study focuses on the calibration of a statistical model of discrimination between several stages of Ganoderma attack on oil palm trees, based on field hyperspectral measurements at tree scale. Field protocol and measurements are first described. Then, combinations of pre-processing, partial least square regression and linear discriminant analysis are tested on about hundred samples to prove the efficiency of canopy reflectance in providing information about the plant sanitary status. A robust algorithm is thus derived, allowing classifying oil-palm in a 4-level typology, based on disease severity from healthy to critically sick stages, with a global performance close to 94%. Moreover, this model discriminates sick from healthy trees with a confidence level of almost 98%. Applications and further improvements of this experiment are finally discussed

Pathway-Based Analysis of a Melanoma Genome-Wide Association Study: Analysis of Genes Related to Tumour-Immunosuppression

Systemic immunosuppression is a risk factor for melanoma, and sunburn-induced immunosuppression is thought to be causal. Genes in immunosuppression pathways are therefore candidate melanoma-susceptibility genes. If variants within these genes individually have a small effect on disease risk, the association may be undetected in genome-wide association (GWA) studies due to low power to reach a high significance level. Pathway-based approaches have been suggested as a method of incorporating a priori knowledge into the analysis of GWA studies. In this study, the association of 1113 single nucleotide polymorphisms (SNPs) in 43 genes (39 genomic regions) related to immunosuppression have been analysed using a gene-set approach in 1539 melanoma cases and 3917 controls from the GenoMEL consortium GWA study. The association between melanoma susceptibility and the whole set of tumour-immunosuppression genes, and also predefined functional subgroups of genes, was considered. The analysis was based on a measure formed by summing the evidence from the most significant SNP in each gene, and significance was evaluated empirically by case-control label permutation. An association was found between melanoma and the complete set of genes (pemp = 0.002), as well as the subgroups related to the generation of tolerogenic dendritic cells (pemp = 0.006) and secretion of suppressive factors (pemp = 0.0004), thus providing preliminary evidence of involvement of tumour-immunosuppression gene polymorphisms in melanoma susceptibility. The analysis was repeated on a second phase of the GenoMEL study, which showed no evidence of an association. As one of the first attempts to replicate a pathway-level association, our results suggest that low power and heterogeneity may present challenges

An Architecture for Fault Tolerant Storage Systems

This paper presents an architectural model for structuring fault tolerant storage systems. This architecture is independent of the semantics of managed data, i.e. it can be applied to a file system, a logging system, or an object store system. The common storage functions used to ensure fault tolerance (e.g. data replication, or distribution) are encapsulated into objects. These may be composed in different ways in order to customize the storage service to some set of failure assumptions. 1 Introduction Fault tolerance is taking a growing importance in storage systems. The challenge is how to build a fault tolerant storage system (FTSS) that can take into account many kinds of faults that can occur in the system, and for each kind of fault an adequate number of occurence of the same fault, without building a monolithic, heavy and closed system. Existing highly fault tolerant storage systems are generally large systems that consume a large amount of resources in order to replicate da..

Issues in Logging Techniques through a Study of Four Systems

This paper presents the main logging techniques issues through a study of four existing logging systems implemented as independent storage systems: Clio, Camelot DLF, K I

KITLOG: a Generic Logging Service

A generic logging service should cater to the variable and even antagonistic needs of clients, without imposing unnecessary overhead on clients that do not use all of its functions. K i t L o g provides an original solution to this problem by decomposing logging characteristics into five mechanisms: buffering policy, distribution of records, replication of records, sharing of logs, and management of physical media. Each characteristic is embodied in a class. For each class, multiple policy implementations can be provided. Instances of these classes are stackable in any appropriate number or order. A client customizes his log, to a particular set of failure assumptions, by selecting adequate classes, instantiating them, and connecting the instances together. 1 Introduction Distributed operating systems must provide tools for reliability. Logs are the greatest common divisor of most reliability mechanisms: well-known algorithms for fault tolerance, such as two-step commitment [1], rec..