2,194 research outputs found
Design of object processing systems
Object processing systems are met rather often in every day life, in industry, tourism, commerce, etc. When designing such a system, many problems can be posed and considered, depending on the scope and purpose of design. We give here a general approach which involves graph theory, and which can have many applications. The generation of possible designs for an object processing system, known as synthesis in the engineering field, is reduced to first solving a graph embedding problem. We believe that our model could be successful and relatively easily implemented in a software tool, called Smart Synthesis Tool, so that the engineering design process will perform quicker. We propose three types of graph transformations which aid the way an object processing system can be designed. Future work will show to which extent these transformation types suffice for generating most of the layouts of the object processing systems
A Security Monitoring Framework For Virtualization Based HEP Infrastructures
High Energy Physics (HEP) distributed computing infrastructures require
automatic tools to monitor, analyze and react to potential security incidents.
These tools should collect and inspect data such as resource consumption, logs
and sequence of system calls for detecting anomalies that indicate the presence
of a malicious agent. They should also be able to perform automated reactions
to attacks without administrator intervention. We describe a novel framework
that accomplishes these requirements, with a proof of concept implementation
for the ALICE experiment at CERN. We show how we achieve a fully virtualized
environment that improves the security by isolating services and Jobs without a
significant performance impact. We also describe a collected dataset for
Machine Learning based Intrusion Prevention and Detection Systems on Grid
computing. This dataset is composed of resource consumption measurements (such
as CPU, RAM and network traffic), logfiles from operating system services, and
system call data collected from production Jobs running in an ALICE Grid test
site and a big set of malware. This malware was collected from security
research sites. Based on this dataset, we will proceed to develop Machine
Learning algorithms able to detect malicious Jobs.Comment: Proceedings of the 22nd International Conference on Computing in High
Energy and Nuclear Physics, CHEP 2016, 10-14 October 2016, San Francisco.
Submitted to Journal of Physics: Conference Series (JPCS
Scalable Global Grid catalogue for LHC Run3 and beyond
The AliEn (ALICE Environment) file catalogue is a global unique namespace
providing mapping between a UNIX-like logical name structure and the
corresponding physical files distributed over 80 storage elements worldwide.
Powerful search tools and hierarchical metadata information are integral parts
of the system and are used by the Grid jobs as well as local users to store and
access all files on the Grid storage elements. The catalogue has been in
production since 2005 and over the past 11 years has grown to more than 2
billion logical file names. The backend is a set of distributed relational
databases, ensuring smooth growth and fast access. Due to the anticipated fast
future growth, we are looking for ways to enhance the performance and
scalability by simplifying the catalogue schema while keeping the functionality
intact. We investigated different backend solutions, such as distributed key
value stores, as replacement for the relational database. This contribution
covers the architectural changes in the system, together with the technology
evaluation, benchmark results and conclusions.Comment: Proceedings of the 22nd International Conference on Computing in High
Energy and Nuclear Physics, CHEP 2016, 10-14 October 2016, San Francisco.
Submitted to Journal of Physics: Conference Series (JPCS
Thermal transport in nanoelectronic devices cooled by on-chip magnetic refrigeration
On-chip demagnetization refrigeration has recently emerged as a powerful tool
for reaching microkelvin electron temperatures in nanoscale structures. The
relative importance of cooling on-chip and off-chip components and the thermal
subsystem dynamics are yet to be analyzed. We study a Coulomb blockade
thermometer with on-chip copper refrigerant both experimentally and
numerically, showing that dynamics in this device are captured by a
first-principles model. Our work shows how to simulate thermal dynamics in
devices down to microkelvin temperatures, and outlines a recipe for a
low-investment platform for quantum technologies and fundamental nanoscience in
this novel temperature range.Comment: 11 pages, 10 figure
Point prevalence of surgical checklist use in Europe: relationship with hospital mortality
Background The prevalence of use of the World Health Organization surgical checklist is unknown. The clinical effectiveness of this intervention in improving postoperative outcomes is debated. Methods We undertook a retrospective analysis of data describing surgical checklist use from a 7 day cohort study of surgical outcomes in 28 European nations (European Surgical Outcomes Study, EuSOS). The analysis included hospitals recruiting >10 patients and excluding outlier hospitals above the 95th centile for mortality. Multivariate logistic regression and three-level hierarchical generalized mixed models were constructed to explore the relationship between surgical checklist use and hospital mortality. Findings are presented as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Results A total of 45 591 patients from 426 hospitals were included in the analysis. A surgical checklist was used in 67.5% patients, with marked variation across countries (0-99.6% of patients). Surgical checklist exposure was associated with lower crude hospital mortality (OR 0.84, CI 0.75-0.94; P=0.002). This effect remained after adjustment for baseline risk factors in a multivariate model (adjusted OR 0.81, CI 0.70-0.94; P<0.005) and strengthened after adjusting for variations within countries and hospitals in a three-level generalized mixed model (adjusted OR 0.71, CI 0.58-0.85; P<0.001). Conclusions The use of surgical checklists varies across European nations. Reported use of a checklist was associated with lower mortality. This observation may represent a protective effect of the surgical checklist itself, or alternatively, may be an indirect indicator of the quality of perioperative care. Clinical trial registration The European Surgical Outcomes Study is registered with ClinicalTrials.gov, number NCT0120360
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