Apus

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Dieter Thomas Tietze - One of the best experts on this subject based on the ideXlab platform.

  • molecular phylogeny of old world swifts aves apodiformes apodidae Apus and tachymarptis based on mitochondrial and nuclear markers
    Molecular Phylogenetics and Evolution, 2012
    Co-Authors: Martin Packert, Jochen Martens, Michael Wink, Anna Feigl, Dieter Thomas Tietze
    Abstract:

    Abstract We provide a molecular phylogeny for Old World swifts of genera Apus and Tachymarptis (tribe Apodini) based on a taxon-complete sampling at the species level. Phylogenetic reconstructions were based on two mitochondrial (cytochrome b , 12S rRNA) and three nuclear markers (introns of fibrinogen and glyceraldehyde 3-phosphate dehydrogenase plus anonymous marker 12884) while the myoglobin intron 2 did not show any intergeneric variation or phylogenetic signal among the target taxa at all. In contrast to previous hypotheses, the two genera Apus and Tachymarptis were shown as reciprocally monophyletic in all reconstructions. Apus was consistently divided into three major clades: (1) East Asian clade of A. pacificus and A. acuticauda , (2) African-Asian clade of A. caffer , A. batesi , A. horus , A. affinis and A. nipalensis , (3) African-Palearctic clade of eight currently accepted species among which sequences of A. Apus and A. pallidus clustered in a terminal crown clade. Phylogenetic signal of all four nuclear markers was extremely shallow within and among species of tribe Apodini and even among genera, such that intra- and intergeneric relationships of Apus , Tachymarptis and Cypsiurus were poorly resolved by nuclear data alone. Four species, A. pacificus , A. barbatus , A. affinis and A. caffer were consistently found to be paraphyletic with respect to their closest relatives and possible taxonomic consequences are discussed without giving particular recommendations due to limitations of sampling. Incomplete mitochondrial lineage sorting with cytochrome- b haplotypes shared among species and across large geographic distances was observed in two species pairs: A. affinis / A. nipalensis and A. Apus / A. pallidus. Mitochondrial introgression caused by extant or past gene flow was ruled out as an explanation for the low interspecific differentiation in these two cases because all nuclear markers appeared to be highly unsorted among Apus species, too. Apparently, the two extant species pairs originated from very recent dispersal and/or speciation events. The currently accepted superspecies classification within Apus was not supported by our results.

Issam Said - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of successive cpus Apus gpus based on an opencl finite difference stencil
    Parallel Distributed and Network-Based Processing, 2013
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    The AMD APU (Accelerated Processing Unit) architecture, which combines CPU and GPU cores on the same die, is promising for GPU applications which performance is bottlenecked by the low PCI Express communication rate. However the first APU generations still have different CPU and GPU memory partitions. Currently, the APU integrated GPUs are also less powerful than discrete GPUs. In this paper we therefore investigate the interest of Apus for scientific computing by evaluating and comparing the performance of two successive AMD Apus (family codename Llano and Trinity), two successive discrete GPUs (chip codename Cayman and Tahiti) and one hexa-core AMD CPU. For this purpose, we rely on a 3D finite difference stencil, that is optimized and tuned in OpenCL. We detail the most interesting optimizations for each architecture and show very good performance in OpenCL: up to 500 Gflops on Tahiti. Finally, our results show that APU integrated GPUs outperform CPUs, and that integrated GPUs of upcoming Apus may match discrete GPUs for problems with high communication requirements.

  • Evaluation of Successive CPUs/Apus/GPUs Based on an OpenCL Finite Difference Stencil
    2013 21st Euromicro International Conference on Parallel Distributed and Network-Based Processing, 2013
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    The AMD APU (Accelerated Processing Unit) architecture, which combines CPU and GPU cores on the same die, is promising for GPU applications which performance is bottlenecked by the low PCI Express communication rate. However the first APU generations still have different CPU and GPU memory partitions. Currently, the APU integrated GPUs are also less powerful than discrete GPUs. In this paper we therefore investigate the interest of Apus for scientific computing by evaluating and comparing the performance of two successive AMD Apus (family codename Llano and Trinity), two successive discrete GPUs (chip codename Cayman and Tahiti) and one hexa-core AMD CPU. For this purpose, we rely on a 3D finite difference stencil, that is optimized and tuned in OpenCL. We detail the most interesting optimizations for each architecture and show very good performance in OpenCL: up to 500 Gflops on Tahiti. Finally, our results show that APU integrated GPUs outperform CPUs, and that integrated GPUs of upcoming Apus may match discrete GPUs for problems with high communication requirements.

  • Assessing the relevance of APU for high performance scientific computing
    2012
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    Fusion Apus eliminate the PCI Express bus which bottlenecks many GPU applications. However, integrated GPUs in Apus are less powerful than discrete GPUs, and while the upcoming Apus will rely on a unified memory, the first Apus still have a distinct GPU memory partition. Hence, it is worthwhile to investigate the applications, as well as problem sizes, for which the GPU part of an APU may outperform a discrete GPU. In this talk we assess the relevance of Llano and Trinity Apus for scientific HPC via hardware and applicative OpenCL micro-benchmarks. We present detailed measurements of CPU-GPU data transfers and performance tests of highly optimized 3D finite difference stencils (a synthetic one and a more realistic and complex one for wave propagation simulations) depending on the frequency of snapshot retrieval. Our results show that integrated GPUs of upcoming Apus can outperform discrete high-end GPUs for medium sized problems with high communication requirements.

Martin Packert - One of the best experts on this subject based on the ideXlab platform.

  • molecular phylogeny of old world swifts aves apodiformes apodidae Apus and tachymarptis based on mitochondrial and nuclear markers
    Molecular Phylogenetics and Evolution, 2012
    Co-Authors: Martin Packert, Jochen Martens, Michael Wink, Anna Feigl, Dieter Thomas Tietze
    Abstract:

    Abstract We provide a molecular phylogeny for Old World swifts of genera Apus and Tachymarptis (tribe Apodini) based on a taxon-complete sampling at the species level. Phylogenetic reconstructions were based on two mitochondrial (cytochrome b , 12S rRNA) and three nuclear markers (introns of fibrinogen and glyceraldehyde 3-phosphate dehydrogenase plus anonymous marker 12884) while the myoglobin intron 2 did not show any intergeneric variation or phylogenetic signal among the target taxa at all. In contrast to previous hypotheses, the two genera Apus and Tachymarptis were shown as reciprocally monophyletic in all reconstructions. Apus was consistently divided into three major clades: (1) East Asian clade of A. pacificus and A. acuticauda , (2) African-Asian clade of A. caffer , A. batesi , A. horus , A. affinis and A. nipalensis , (3) African-Palearctic clade of eight currently accepted species among which sequences of A. Apus and A. pallidus clustered in a terminal crown clade. Phylogenetic signal of all four nuclear markers was extremely shallow within and among species of tribe Apodini and even among genera, such that intra- and intergeneric relationships of Apus , Tachymarptis and Cypsiurus were poorly resolved by nuclear data alone. Four species, A. pacificus , A. barbatus , A. affinis and A. caffer were consistently found to be paraphyletic with respect to their closest relatives and possible taxonomic consequences are discussed without giving particular recommendations due to limitations of sampling. Incomplete mitochondrial lineage sorting with cytochrome- b haplotypes shared among species and across large geographic distances was observed in two species pairs: A. affinis / A. nipalensis and A. Apus / A. pallidus. Mitochondrial introgression caused by extant or past gene flow was ruled out as an explanation for the low interspecific differentiation in these two cases because all nuclear markers appeared to be highly unsorted among Apus species, too. Apparently, the two extant species pairs originated from very recent dispersal and/or speciation events. The currently accepted superspecies classification within Apus was not supported by our results.

Henri Calandra - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of successive cpus Apus gpus based on an opencl finite difference stencil
    Parallel Distributed and Network-Based Processing, 2013
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    The AMD APU (Accelerated Processing Unit) architecture, which combines CPU and GPU cores on the same die, is promising for GPU applications which performance is bottlenecked by the low PCI Express communication rate. However the first APU generations still have different CPU and GPU memory partitions. Currently, the APU integrated GPUs are also less powerful than discrete GPUs. In this paper we therefore investigate the interest of Apus for scientific computing by evaluating and comparing the performance of two successive AMD Apus (family codename Llano and Trinity), two successive discrete GPUs (chip codename Cayman and Tahiti) and one hexa-core AMD CPU. For this purpose, we rely on a 3D finite difference stencil, that is optimized and tuned in OpenCL. We detail the most interesting optimizations for each architecture and show very good performance in OpenCL: up to 500 Gflops on Tahiti. Finally, our results show that APU integrated GPUs outperform CPUs, and that integrated GPUs of upcoming Apus may match discrete GPUs for problems with high communication requirements.

  • Evaluation of Successive CPUs/Apus/GPUs Based on an OpenCL Finite Difference Stencil
    2013 21st Euromicro International Conference on Parallel Distributed and Network-Based Processing, 2013
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    The AMD APU (Accelerated Processing Unit) architecture, which combines CPU and GPU cores on the same die, is promising for GPU applications which performance is bottlenecked by the low PCI Express communication rate. However the first APU generations still have different CPU and GPU memory partitions. Currently, the APU integrated GPUs are also less powerful than discrete GPUs. In this paper we therefore investigate the interest of Apus for scientific computing by evaluating and comparing the performance of two successive AMD Apus (family codename Llano and Trinity), two successive discrete GPUs (chip codename Cayman and Tahiti) and one hexa-core AMD CPU. For this purpose, we rely on a 3D finite difference stencil, that is optimized and tuned in OpenCL. We detail the most interesting optimizations for each architecture and show very good performance in OpenCL: up to 500 Gflops on Tahiti. Finally, our results show that APU integrated GPUs outperform CPUs, and that integrated GPUs of upcoming Apus may match discrete GPUs for problems with high communication requirements.

  • Assessing the relevance of APU for high performance scientific computing
    2012
    Co-Authors: Henri Calandra, Romain Dolbeau, Pierre Fortin, Jean-luc Lamotte, Issam Said
    Abstract:

    Fusion Apus eliminate the PCI Express bus which bottlenecks many GPU applications. However, integrated GPUs in Apus are less powerful than discrete GPUs, and while the upcoming Apus will rely on a unified memory, the first Apus still have a distinct GPU memory partition. Hence, it is worthwhile to investigate the applications, as well as problem sizes, for which the GPU part of an APU may outperform a discrete GPU. In this talk we assess the relevance of Llano and Trinity Apus for scientific HPC via hardware and applicative OpenCL micro-benchmarks. We present detailed measurements of CPU-GPU data transfers and performance tests of highly optimized 3D finite difference stencils (a synthetic one and a more realistic and complex one for wave propagation simulations) depending on the frequency of snapshot retrieval. Our results show that integrated GPUs of upcoming Apus can outperform discrete high-end GPUs for medium sized problems with high communication requirements.

Guofei Gu - One of the best experts on this subject based on the ideXlab platform.

  • IEEE Symposium on Security and Privacy - Study and Mitigation of Origin Stripping Vulnerabilities in Hybrid-postMessage Enabled Mobile Applications
    2018 IEEE Symposium on Security and Privacy (SP), 2018
    Co-Authors: Guangliang Yang, Guofei Gu, Jeff Huang, Abner Mendoza
    Abstract:

    postMessage is popular in HTML5 based web apps to allow the communication between different origins. With the increasing popularity of the embedded browser (i.e., WebView) in mobile apps (i.e., hybrid apps), postMessage has found utility in these apps. However, different from web apps, hybrid apps have a unique requirement that their native code (e.g., Java for Android) also needs to exchange messages with web code loaded in WebView. To bridge the gap, developers typically extend postMessage by treating the native context as a new frame, and allowing the communication between the new frame and the web frames. We term such extended postMessage "hybrid postMessage" in this paper. We find that hybrid postMessage introduces new critical security flaws: all origin information of a message is not respected or even lost during the message delivery in hybrid postMessage. If adversaries inject malicious code into WebView, the malicious code may leverage the flaws to passively monitor messages that may contain sensitive information, or actively send messages to arbitrary message receivers and access their internal functionalities and data. We term the novel security issue caused by hybrid postMessage "Origin Stripping Vulnerability" (OSV). In this paper, our contributions are fourfold. First, we conduct the first systematic study on OSV. Second, we propose a lightweight detection tool against OSV, called OSV-Hunter. Third, we evaluate OSV-Hunter using a set of popular apps. We found that 74 apps implemented hybrid postMessage, and all these apps suffered from OSV, which might be exploited by adversaries to perform remote real-time microphone monitoring, data race, internal data manipulation, denial of service (DoS) attacks and so on. Several popular development frameworks, libraries (such as the Facebook React Native framework, and the Google cloud print library) and apps (such as Adobe Reader and WPS office) are impacted. Lastly, to mitigate OSV from the root, we design and implement three new postMessage APIs, called OSV-Free. Our evaluation shows that OSV-Free is secure and fast, and it is generic and resilient to the notorious Android fragmentation problem. We also demonstrate that OSV-Free is easy to use, by applying OSV-Free to harden the complex "Facebook React Native" framework. OSV-Free is open source, and its source code and more implementation and evaluation details are available online.

  • Mobile Application Web API Reconnaissance: Web-to-Mobile Inconsistencies & Vulnerabilities
    Proceedings - IEEE Symposium on Security and Privacy, 2018
    Co-Authors: Abner Mendoza, Guofei Gu
    Abstract:

    —Modern mobile apps use cloud-hosted HTTP-based API services and heavily rely on the Internet infrastructure for data communication and storage. To improve performance and leverage the power of the mobile device, input validation and other business logic required for interfacing with web API services are typically implemented on the mobile client. However, when a web service implementation fails to thoroughly replicate input validation, it gives rise to inconsistencies that could lead to attacks that can compromise user security and privacy. Developing automatic methods of auditing web APIs for security remains challenging. In this paper, we present a novel approach for automatically analyzing mobile app-to-web API communication to detect in-consistencies in input validation logic between apps and their respective web API services. We present our system, WARDroid, which implements a static analysis-based web API reconnaissance approach to uncover inconsistencies on real world API services that can lead to attacks with severe consequences for potentially millions of users throughout the world. Our system utilizes program analysis techniques to automatically extract HTTP communication templates from Android apps that encode the input validation constraints imposed by the apps on outgoing web requests to web API services. WARDroid is also enhanced with blackbox testing of server validation logic to identify inconsistencies that can lead to attacks. We evaluated our system on a set of 10,000 popular free apps from the Google Play Store. We detected problematic logic in APIs used in over 4,000 apps, including 1,743 apps that use unencrypted HTTP communication. We further tested 1,000 apps to validate web API hijacking vulnerabilities that can lead to potential compromise of user privacy and security and found that millions of users are potentially affected from our sample set of tested apps.

  • Study and Mitigation of Origin Stripping Vulnerabilities in Hybrid-postMessage Enabled Mobile Applications
    Proceedings - IEEE Symposium on Security and Privacy, 2018
    Co-Authors: Guangliang Yang, Guofei Gu, Jeff Huang, Abner Mendoza
    Abstract:

    —postMessage is popular in HTML5 based web apps to allow the communication between different origins. With the increasing popularity of the embedded browser (i.e., WebView) in mobile apps (i.e., hybrid apps), postMessage has found utility in these apps. However, different from web apps, hybrid apps have a unique requirement that their native code (e.g., Java for Android) also needs to exchange messages with web code loaded in Web-View. To bridge the gap, developers typically extend postMessage by treating the native context as a new frame, and allowing the communication between the new frame and the web frames. We term such extended postMessage " hybrid postMessage " in this paper. We find that hybrid postMessage introduces new critical security flaws: all origin information of a message is not respected or even lost during the message delivery in hybrid postMessage. If adversaries inject malicious code into WebView, the malicious code may leverage the flaws to passively monitor messages that may contain sensitive information, or actively send messages to arbitrary message receivers and access their internal functionalities and data. We term the novel security issue caused by hybrid postMessage " Origin Stripping Vulnerability " (OSV). In this paper, our contributions are fourfold. First, we con-duct the first systematic study on OSV. Second, we propose a lightweight detection tool against OSV, called OSV-Hunter. Third, we evaluate OSV-Hunter using a set of popular apps. We found that 74 apps implemented hybrid postMessage, and all these apps suffered from OSV, which might be exploited by adversaries to perform remote real-time microphone monitoring, data race, internal data manipulation, denial of service (DoS) attacks and so on. Several popular development frameworks, libraries (such as the Facebook React Native framework, and the Google cloud print library) and apps (such as Adobe Reader and WPS office) are impacted. Lastly, to mitigate OSV from the root, we design and implement three new postMessage APIs, called OSV-Free. Our evaluation shows that OSV-Free is secure and fast, and it is generic and resilient to the notorious Android fragmentation problem. We also demonstrate that OSV-Free is easy to use, by applying OSV-Free to harden the complex " Facebook React Native " framework. OSV-Free is open source, and its source code and more implementation and evaluation details are available online.

  • UIPicker: User-input Privacy Identification in Mobile Applications
    Proceedings of the 24th USENIX Conference on Security Symposium, 2015
    Co-Authors: Yuhong Nan, Shunfan Zhou, Guofei Gu, Zhemin Yang, Min Yang, Xiaofeng Wang
    Abstract:

    Identifying sensitive user inputs is a prerequisite for pri- vacy protection.When it comes to today’s programanal- ysis systems, however, only those data that go through well-defined system APIs can be automatically labelled. In our research, we show that this conventional approach is far from adequate, as most sensitive inputs are actu- ally entered by the user at an app’s runtime: in our re- search, we inspect 17, 425 top apps from Google Play, and find that 35.46% of them involve sensitive user in- puts. Manuallymarking theminvolves a lot of effort, im- peding a large-scale, automated analysis of apps for po- tential information leaks. To address this important issue, we present UIPicker, an adaptable framework for auto- matic identification of sensitive user inputs. UIPicker is designed to detect the semantic information within the application layout resources and program code, and fur- ther analyze it for the locations where security-critical information may show up. This approach can support a variety of existing security analysis on mobile apps. We further develop a runtime protection mechanism on top of the technique, which helps the user make informed decisions when her sensitive data is about to leave the device in an unexpected way. We evaluate our approach over 200 randomly selected popular apps on Google- Play. UIPicker is able to accurately label sensitive user inputsmost of the time, with 93.6% precision and 90.1% recall.

  • VulHunter: Toward discovering vulnerabilities in android applications
    IEEE Micro, 2015
    Co-Authors: Chenxiong Qian, Xiapu Luo, Yu Le, Guofei Gu
    Abstract:

    With the prosperity of the Android app economy, many apps have been published and sold in various markets. However, short development cycles and insufficient security development guidelines have led to many vulnerable apps. Although some systems have been developed for automatically discovering specific vulnerabilities in apps, their effectiveness and efficiency are usually restricted because of the exponential growth of paths to examine and simplified assumptions. In this article, the authors propose a new static-analysis framework for facilitating security analysts to detect vulnerable apps from three aspects. First, they propose an app property graph (APG), a new data structure containing detailed and precise information from apps. Second, by modeling app-related vulnerabilities as graph traversals, the authors conduct graph traversals over APGs to identify vulnerable apps for easing the identification process. Third, they reduce the workload of manual verification by removing infeasible paths and generating attack inputs whenever possible. They have implemented the framework in a system named VulHunter with 9,145 lines of Java code and modeled five types of vulnerabilities. Checking 557 popular apps that are randomly collected from Google Play and have at least 1 million installations, the authors found that 375 apps (67.3 percent) have at least one vulnerability. [ABSTRACT FROM PUBLISHER]