Optimization of Cloud Task Processing with Checkpoint-Restart Mechanism

International audienceIn this paper, we aim at optimizing fault-tolerance tech- niques based on a checkpointing/restart mechanism, in the context of cloud computing. Our contribution is three-fold. (1) We derive a fresh formula to compute the optimal num- ber of checkpoints for cloud jobs with varied distributions of failure events. Our analysis is not only generic with no assumption on failure probability distribution, but also at- tractively simple to apply in practice. (2) We design an adaptive algorithm to optimize the impact of checkpointing regarding various costs like checkpointing/restart overhead. (3) We evaluate our optimized solution in a real cluster en- vironment with hundreds of virtual machines and Berke- ley Lab Checkpoint/Restart tool. Task failure events are emulated via a production trace produced on a large-scale Google data center. Experiments confirm that our solution is fairly suitable for Google systems. Our optimized formula outperforms Young's formula by 3-10 percent, reducing wall- clock lengths by 50-100 seconds per job on average

From Freud's unconscious to Lacan's subject : identification from Freud to Lacan via Conté

The thesis starts with the question: 'Does there exist a subject in Freud?' and looks for answers first in Freud's early formulations of the psychical apparatus in the 'Project (1895), 'Letter 52' to Fliess (1896), then Chapter VII of 'The Interpretation of Dreams' (1900), that is his first topography. The answer confirms our claim that there exists a subject in Freud, that it is unconscious and that it is largely included in and concealed by the Freudian term of 'ego' (Ich). In Chapter 2, our claim is carried forward through the second period of Freud's work to another aspect of Ich, not as unconscious, but as the narcissistic ego. Freud's introduction to the theory of narcissism (1914c) highlighted the dimension of ego as a libidinal object and its role in psychosis. The metapsychological papers, 'Drives and their Vicissitudes' (1915c), 'Repression' (1915d) and 'The Unconscious' (1915e) proved on the other hand that Freud had not abandoned his research on the structural, the symbolic dimension of the ego (Ich). In Chapter 3 the thesis focuses on two particular aspects of Freudian metapsychology, the structure of the ideals and identification. The sub-claim here is that identification in Freud is not simply an imaginary process involving regression from love, but also a particular substructure of the 'ego'. We develop this claim through the study of 'Group Psychology' (1921c) and Freud's second topography in the 'Ego and the Id' (1923b). In Chapter 4, we present a post-Freudian, object relations, view of the psychical structure, that is D. Lagache's : 'Psychoanalysis and Personality's Structure' (1958) and Lacan's own counter-presentation of the psychical structure as an 'Optical Schema' (1958), named after a model he adapted from experimental 19th century physics. In Chapter 5, we present Lacan's largely unknown theory of identification, as he developed it in Seminar IX Identification(1961-1962), first the identification of the subject to the signifier, then to object a. This supports our final claim that the formalization of object a and the status of the Real were first developed in Seminar IX, which is before Seminars Book X and XI. In Chapter 6, we present two major contributions by C. Conté , 'The Splitting of the Subject and his Identification'(1970) and 'Topological Surfaces' (1993) which lead us to conclude that Topology and the Real are the areas of research most suited to contemporary psychoanalysis which only now begin to show their relevance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

DEVELOPING A METHODOLOGICAL FRAMEWORK FOR THE PARTICIPATORY MEASUREMENT OF SUSTAINABILITY

The measurement of sustainability can provide significant information in order to plan and implement environmental policies. Several methods have been proposed in the literature in order to select the appropriate indicators along with a variety of techniques for their measurement. These methods are often divided in two main categories: a) a top-down approach where the selection of sustainability indicators is often based on the decision of scientists and policy-makers and b) a bottom-up approach where local stakeholders influence the selection and the measurement of indicators. In this paper we propose a methodological framework which allows the selection of sustainability indicators based on scientific research but at the same time allows citizens to influence both the selection of indicators and their measurement. The benefits of the specific methodological framework are two: a) to incorporate in different stages of the measurement the opinions of local stakeholders, b) to assist in policy decision-making through the assessment of the current situation of sustainability

Deglacial and Holocene sea-ice and climate dynamics in the Bransfield Strait, northern Antarctic Peninsula

The reconstruction of past sea-ice distribution in the Southern Ocean is crucial for an improved understanding of ice–ocean–atmosphere feedbacks and the evaluation of Earth system and Antarctic ice sheet models. The Antarctic Peninsula (AP) has been experiencing a warming since the start of regular monitoring of the atmospheric temperature in the 1950s. The associated decrease in sea-ice cover contrasts the trend of growing sea-ice extent in East Antarctica. To reveal the long-term sea-ice history at the northern Antarctic Peninsula (NAP) under changing climate conditions, we examined a marine sediment core from the eastern basin of the Bransfield Strait covering the last Deglacial and the Holocene. For sea-ice reconstructions, we focused on the specific sea-ice biomarker lipid IPSO25, a highly branched isoprenoid (HBI), and sea-ice diatoms, whereas a phytoplankton-derived HBI triene (C25:3) and warmer open-ocean diatom assemblages reflect predominantly ice-free conditions. We further reconstruct ocean temperatures using glycerol dialkyl glycerol tetraethers (GDGTs) and diatom assemblages and compare our sea-ice and temperature records with published marine sediment and ice core data. A maximum ice cover is observed during the Antarctic Cold Reversal 13 800–13 000 years before present (13.8–13 ka), while seasonally ice-free conditions permitting (summer) phytoplankton productivity are reconstructed for the late Deglacial and the Early Holocene from 13 to 8.3 ka. An overall decreasing sea-ice trend throughout the Middle Holocene coincides with summer ocean warming and increasing phytoplankton productivity. The Late Holocene is characterized by highly variable winter sea-ice concentrations and a sustained decline in the duration and/or concentration of spring sea ice. Overall diverging trends in GDGT-based TEX86L and RI-OH' subsurface ocean temperatures (SOTs) are found to be linked to opposing spring and summer insolation trends, respectively.</p

The impact of corporate social responsibility disclosure on financial performance : evidence from the GCC Islamic banking sector.

This paper examines the relationship between corporate social responsibility (CSR) and financial performance for Islamic banks in the Gulf Cooperation Council (GCC) region over the period 2000–2014 by generating CSR-related data through disclosure analysis of the annual reports of the sampled banks. The findings of this study indicate that there is a significant positive relationship between CSR disclosure and the financial performance of Islamic banks in the GCC countries. The results also show a positive relationship between CSR disclosure and the future financial performance of GCC Islamic banks, potentially indicating that current CSR activities carried out by Islamic banks in the GCC could have a long-term impact on their financial performance. Furthermore, despite demonstrating a significant positive relationship between the composite measure of the CSR disclosure index and financial performance, the findings show no statistically significant relationship between the individual dimensions of the CSR disclosure index and the current financial performance measure except for ‘mission and vision’ and ‘products and services’. Similarly, the empirical results detect a positive significant association only between ‘mission and vision’ dimension and future financial performance of the examined banks