The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Philippa Gardner - One of the best experts on this subject based on the ideXlab platform.
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OOPSLA - Reasoning about the POSIX file system: Local update and global pathnames
Proceedings of the 2015 ACM SIGPLAN International Conference on Object-Oriented Programming Systems Languages and Applications, 2015Co-Authors: Gian Ntzik, Philippa GardnerAbstract:We introduce a program logic for specifying a core sequential subset of the POSIX file system and for reasoning abstractly about client programs working with the file system. The challenge is to reason about the combination of Local Directory update and global pathname traversal (including '..' and symbolic links) which may overlap the directories being updated. Existing reasoning techniques are either based on first-order logic and do not scale, or on separation logic and can only handle linear pathnames (no '..' or symbolic links). We introduce fusion logic for reasoning about Local update and global pathname traversal, introducing a novel effect frame rule to propagate the effect of a Local update on overlapping pathnames. We apply our reasoning to the standard recursive remove utility (rm -r), discovering bugs in well-known implementations.
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Reasoning about the POSIX File System: Local Update and Global Pathnames, Technical Report
2015Co-Authors: Gian Ntzik, Philippa GardnerAbstract:We introduce a program logic for specifying a core sequential subset of the POSIX file system and for reasoning abstractly about client programs working with the file system. The challenge is to reason about the combination of Local Directory update and global pathname traversal (including ’..’ and symbolic links) which may overlap the directories being updated. Existing reasoning techniques are either based on first-order logic and do not scale, or on separation logic and can only handle linear pathnames (no ’..’ or symbolic links). We introduce fusion logic for reasoning about Local update and global pathname traversal, introducing a novel effect frame rule to propagate the effect of a Local update on overlapping pathnames. We apply our reasoning to the standard recursive remove utility (rm -r), discovering bugs in well-known implementations.
Fiona Stapleton - One of the best experts on this subject based on the ideXlab platform.
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Queensland Microbial Keratitis Database: 2005-2015.
The British journal of ophthalmology, 2019Co-Authors: Matthew Green, Nicole Carnt, Andrew Apel, Fiona StapletonAbstract:Aims To estimate the incidence of culture-positive microbial keratitis in Queensland and analyse trends in the organisms and their sensitivities cultured from corneal scrapes, especially low-incidence organisms. Methods Retrospective multicentre case series of all positive corneal scrapes in Queensland, Australia between 2005 and 2015. Pathology organisations in Queensland were identified by online and Local Directory search and agreed to participate. Digital records of scrapes provided patient demographics and culture and susceptibility results. Trends in the incidence, organisms and sensitivities were monitored with linear regression. The yearly incidence of microbial keratitis was estimated from the Queensland population. Results The included corneal scrapes totalled 3182, while 1006 were excluded. The included scrapes yielded 4111 organisms. Pseudomonas aeruginosa was the most common single isolate (729, 17.7%), although Gram-positive organisms were more common overall (2737, 66.6%). Fungal organisms were cultured in 6% of cases, while Acanthamoeba comprised only 1% of records. Bacterial organisms were sensitive to all recorded antibiotics in 89% of all isolates and none of the reported antibiotics showed a decreasing trend in susceptibility. The incidence of protozoal isolation decreased over time (p=0.055). Cultures positive for yeasts showed a linear increase in incidence (p=0.045) while moulds showed a spike in incidence in 2010–2012 (p=0.0008). Conclusion The estimated incidence of microbial keratitis was 0.66 cases per 10 000 people, the rate of antibiotic susceptibility is high and stable, the incidence of keratitis secondary to protozoa is likely to be decreasing while the incidence of keratitis culturing yeast is increasing.
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Pediatric Microbial Keratitis in Queensland, Australia (2005 to 2015).
Cornea, 2019Co-Authors: Matthew Green, Andrew Apel, Fiona StapletonAbstract:PURPOSE To estimate the incidence and define the demographic and microbiological profile of pediatric microbial keratitis (MK) in Queensland, Australia. METHODS This is a retrospective study based on the multicenter database of all patients with positive corneal scrapes in Queensland, Australia, between 2005 and 2015. Pathology organizations in Queensland were identified by online and Local Directory search and were requested to provide digital records of the corneal scrapes, including patient demographics and culture and antibiotic sensitivity results. Patient demographics, yearly incidence (based on state population data), cultured organisms, and antibiotic sensitivities in MK in patients 16 years old or younger with keratitis were reported and compared with adults. RESULTS Pediatric cases comprised 125 cases of a total 3182 (3.9%) included in the database. The yearly incidence of MK in children was estimated to be 0.11 cases per 10,000 people 16 years old or younger (95% confidence interval, 0.086-0.134), which was significantly lower than the estimated incidence in people older than 16 years (0.82 per 10,000 people; 95% confidence interval, 0.72-0.92; P < 0.0001). The average age of pediatric patients was 9.2 years (SD 5.5). Culture results showed Gram-positive organisms were the most common causative organisms (84%; 67.2%), Pseudomonas aeruginosa was the most common single organism (24%; 19.2%), and fungal recovery was low (4%; 3.2%). Cultures positive for Streptococcus pneumoniae (17%; 13.6%; P < 0.001) and bacteria sensitive to all recorded antibiotics (96.8%; P < 0.001) were significantly more common in children. CONCLUSIONS MK in pediatric patients is less common than in adults. Although Streptococcus pneumoniae was more common in children, P. aeruginosa was the most common isolate.
Gian Ntzik - One of the best experts on this subject based on the ideXlab platform.
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OOPSLA - Reasoning about the POSIX file system: Local update and global pathnames
Proceedings of the 2015 ACM SIGPLAN International Conference on Object-Oriented Programming Systems Languages and Applications, 2015Co-Authors: Gian Ntzik, Philippa GardnerAbstract:We introduce a program logic for specifying a core sequential subset of the POSIX file system and for reasoning abstractly about client programs working with the file system. The challenge is to reason about the combination of Local Directory update and global pathname traversal (including '..' and symbolic links) which may overlap the directories being updated. Existing reasoning techniques are either based on first-order logic and do not scale, or on separation logic and can only handle linear pathnames (no '..' or symbolic links). We introduce fusion logic for reasoning about Local update and global pathname traversal, introducing a novel effect frame rule to propagate the effect of a Local update on overlapping pathnames. We apply our reasoning to the standard recursive remove utility (rm -r), discovering bugs in well-known implementations.
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Reasoning about the POSIX File System: Local Update and Global Pathnames, Technical Report
2015Co-Authors: Gian Ntzik, Philippa GardnerAbstract:We introduce a program logic for specifying a core sequential subset of the POSIX file system and for reasoning abstractly about client programs working with the file system. The challenge is to reason about the combination of Local Directory update and global pathname traversal (including ’..’ and symbolic links) which may overlap the directories being updated. Existing reasoning techniques are either based on first-order logic and do not scale, or on separation logic and can only handle linear pathnames (no ’..’ or symbolic links). We introduce fusion logic for reasoning about Local update and global pathname traversal, introducing a novel effect frame rule to propagate the effect of a Local update on overlapping pathnames. We apply our reasoning to the standard recursive remove utility (rm -r), discovering bugs in well-known implementations.
Matthew Green - One of the best experts on this subject based on the ideXlab platform.
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Queensland Microbial Keratitis Database: 2005-2015.
The British journal of ophthalmology, 2019Co-Authors: Matthew Green, Nicole Carnt, Andrew Apel, Fiona StapletonAbstract:Aims To estimate the incidence of culture-positive microbial keratitis in Queensland and analyse trends in the organisms and their sensitivities cultured from corneal scrapes, especially low-incidence organisms. Methods Retrospective multicentre case series of all positive corneal scrapes in Queensland, Australia between 2005 and 2015. Pathology organisations in Queensland were identified by online and Local Directory search and agreed to participate. Digital records of scrapes provided patient demographics and culture and susceptibility results. Trends in the incidence, organisms and sensitivities were monitored with linear regression. The yearly incidence of microbial keratitis was estimated from the Queensland population. Results The included corneal scrapes totalled 3182, while 1006 were excluded. The included scrapes yielded 4111 organisms. Pseudomonas aeruginosa was the most common single isolate (729, 17.7%), although Gram-positive organisms were more common overall (2737, 66.6%). Fungal organisms were cultured in 6% of cases, while Acanthamoeba comprised only 1% of records. Bacterial organisms were sensitive to all recorded antibiotics in 89% of all isolates and none of the reported antibiotics showed a decreasing trend in susceptibility. The incidence of protozoal isolation decreased over time (p=0.055). Cultures positive for yeasts showed a linear increase in incidence (p=0.045) while moulds showed a spike in incidence in 2010–2012 (p=0.0008). Conclusion The estimated incidence of microbial keratitis was 0.66 cases per 10 000 people, the rate of antibiotic susceptibility is high and stable, the incidence of keratitis secondary to protozoa is likely to be decreasing while the incidence of keratitis culturing yeast is increasing.
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Pediatric Microbial Keratitis in Queensland, Australia (2005 to 2015).
Cornea, 2019Co-Authors: Matthew Green, Andrew Apel, Fiona StapletonAbstract:PURPOSE To estimate the incidence and define the demographic and microbiological profile of pediatric microbial keratitis (MK) in Queensland, Australia. METHODS This is a retrospective study based on the multicenter database of all patients with positive corneal scrapes in Queensland, Australia, between 2005 and 2015. Pathology organizations in Queensland were identified by online and Local Directory search and were requested to provide digital records of the corneal scrapes, including patient demographics and culture and antibiotic sensitivity results. Patient demographics, yearly incidence (based on state population data), cultured organisms, and antibiotic sensitivities in MK in patients 16 years old or younger with keratitis were reported and compared with adults. RESULTS Pediatric cases comprised 125 cases of a total 3182 (3.9%) included in the database. The yearly incidence of MK in children was estimated to be 0.11 cases per 10,000 people 16 years old or younger (95% confidence interval, 0.086-0.134), which was significantly lower than the estimated incidence in people older than 16 years (0.82 per 10,000 people; 95% confidence interval, 0.72-0.92; P < 0.0001). The average age of pediatric patients was 9.2 years (SD 5.5). Culture results showed Gram-positive organisms were the most common causative organisms (84%; 67.2%), Pseudomonas aeruginosa was the most common single organism (24%; 19.2%), and fungal recovery was low (4%; 3.2%). Cultures positive for Streptococcus pneumoniae (17%; 13.6%; P < 0.001) and bacteria sensitive to all recorded antibiotics (96.8%; P < 0.001) were significantly more common in children. CONCLUSIONS MK in pediatric patients is less common than in adults. Although Streptococcus pneumoniae was more common in children, P. aeruginosa was the most common isolate.
João Paulo Barraca - One of the best experts on this subject based on the ideXlab platform.
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Dynamic, scalable and flexible resource discovery for large-dimension many-core systems
Future Generation Computer Systems, 2015Co-Authors: Javad Zarrin, Rui L. Aguiar, João Paulo BarracaAbstract:Future large scale systems will execute novel operating systems running across many chips with many cores. In this highly distributed environment, resource discovery is an important building block. Resource discovery aims to match the application's demands to the existing (distributed) resources, by discovering and finding resources at run-time, and then selecting the best resource that matches the application running requirements. The main contribution of this paper is the design and evolution of a highly scalable, highly flexible, resource discovery model for such heterogeneous environments. The model is based on self-organizing processing resources in the system according to a hierarchical resource description where each group of resources has a Local Directory that collects and keeps the information of the underlying resource members (cores) in different layers. Operationally, at each layer, it consists of a peer-to-peer architecture of modules that, by interacting with each other, provide a global view of the resource availability in a large, dynamic and heterogeneous distributed environment. The proposed resource discovery model provides the adaptability and flexibility to perform complex querying by supporting a large set of significant querying features (such as multi-dimensional, range and aggregate querying) while supporting exact and partial matching, both for static and dynamic object contents. The paper demonstrates by simulation how the proposed model can deal with issues such as scalability, efficiency and adaptability of resource discovery in future many-core systems which are the major challenges in the current state of the art. The simulation shows that the proposed resource discovery model can be applied to arbitrary scales of dynamicity, both in terms of complexity and of scale, positioning this proposal as a good architecture for future many-core systems. A novel resource discovery architecture for large-scale systems.A resource description model designed for maximum scalability.Simulations and analysis of such a resource discovery architecture.Results show vast scalability and adaptability.