The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

David B Slemmons - One of the best experts on this subject based on the ideXlab platform.

  • Geometric pattern, rupture termination and Fault Segmentation of the Dixie Valley—Pleasant Valley active normal Fault system, Nevada, U.S.A.
    Journal of Structural Geology, 1991
    Co-Authors: Peizhen Zhang, David B Slemmons
    Abstract:

    Abstract Active Fault systems of both interplate and intraplate settings clearly show patterns of Segmentation. Fault Segmentation, therefore, is very important for understanding Fault behavior and assessing seismic hazard. The complexity of geometric patterns along Fault systems has a strong influence on the propagation of earthquake ruptures, because it can form structural heterogeneities that tend to inhibit rupture propagation. This implies that there should be relations between Fault Segmentation and the complexity of Fault geometry. The active normal Faults of the Dixie Valley—Pleasant Valley system provide an excellent example to study such relations and to establish the geometric method of normal Fault Segmentation in the Basin and Range province. Studies of Fault Segmentation in the Dixie Valley—Pleasant Valley Fault system indicate that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary. The characteristics of segment boundaries on normal Faults of the Dixie Valley—Pleasant Valley system can be explained in terms of the nature of rupture propagation and termination. These changes may be helpful criteria for distinguishing normal Fault Segmentation at least in the Basin and Range province.

  • geometric pattern rupture termination and Fault Segmentation of the dixie valley pleasant valley active normal Fault system nevada u s a
    Journal of Structural Geology, 1991
    Co-Authors: Peizhen Zhang, David B Slemmons
    Abstract:

    Abstract Active Fault systems of both interplate and intraplate settings clearly show patterns of Segmentation. Fault Segmentation, therefore, is very important for understanding Fault behavior and assessing seismic hazard. The complexity of geometric patterns along Fault systems has a strong influence on the propagation of earthquake ruptures, because it can form structural heterogeneities that tend to inhibit rupture propagation. This implies that there should be relations between Fault Segmentation and the complexity of Fault geometry. The active normal Faults of the Dixie Valley—Pleasant Valley system provide an excellent example to study such relations and to establish the geometric method of normal Fault Segmentation in the Basin and Range province. Studies of Fault Segmentation in the Dixie Valley—Pleasant Valley Fault system indicate that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary. The characteristics of segment boundaries on normal Faults of the Dixie Valley—Pleasant Valley system can be explained in terms of the nature of rupture propagation and termination. These changes may be helpful criteria for distinguishing normal Fault Segmentation at least in the Basin and Range province.

Peizhen Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Geometric pattern, rupture termination and Fault Segmentation of the Dixie Valley—Pleasant Valley active normal Fault system, Nevada, U.S.A.
    Journal of Structural Geology, 1991
    Co-Authors: Peizhen Zhang, David B Slemmons
    Abstract:

    Abstract Active Fault systems of both interplate and intraplate settings clearly show patterns of Segmentation. Fault Segmentation, therefore, is very important for understanding Fault behavior and assessing seismic hazard. The complexity of geometric patterns along Fault systems has a strong influence on the propagation of earthquake ruptures, because it can form structural heterogeneities that tend to inhibit rupture propagation. This implies that there should be relations between Fault Segmentation and the complexity of Fault geometry. The active normal Faults of the Dixie Valley—Pleasant Valley system provide an excellent example to study such relations and to establish the geometric method of normal Fault Segmentation in the Basin and Range province. Studies of Fault Segmentation in the Dixie Valley—Pleasant Valley Fault system indicate that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary. The characteristics of segment boundaries on normal Faults of the Dixie Valley—Pleasant Valley system can be explained in terms of the nature of rupture propagation and termination. These changes may be helpful criteria for distinguishing normal Fault Segmentation at least in the Basin and Range province.

  • geometric pattern rupture termination and Fault Segmentation of the dixie valley pleasant valley active normal Fault system nevada u s a
    Journal of Structural Geology, 1991
    Co-Authors: Peizhen Zhang, David B Slemmons
    Abstract:

    Abstract Active Fault systems of both interplate and intraplate settings clearly show patterns of Segmentation. Fault Segmentation, therefore, is very important for understanding Fault behavior and assessing seismic hazard. The complexity of geometric patterns along Fault systems has a strong influence on the propagation of earthquake ruptures, because it can form structural heterogeneities that tend to inhibit rupture propagation. This implies that there should be relations between Fault Segmentation and the complexity of Fault geometry. The active normal Faults of the Dixie Valley—Pleasant Valley system provide an excellent example to study such relations and to establish the geometric method of normal Fault Segmentation in the Basin and Range province. Studies of Fault Segmentation in the Dixie Valley—Pleasant Valley Fault system indicate that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary. The characteristics of segment boundaries on normal Faults of the Dixie Valley—Pleasant Valley system can be explained in terms of the nature of rupture propagation and termination. These changes may be helpful criteria for distinguishing normal Fault Segmentation at least in the Basin and Range province.

Fausto Spoto - One of the best experts on this subject based on the ideXlab platform.

  • Precise null-pointer analysis
    Software & Systems Modeling, 2011
    Co-Authors: Fausto Spoto
    Abstract:

    In Java, C or C++, attempts to dereference the null value result in an exception or a Segmentation Fault. Hence, it is important to identify those program points where this undesired behaviour might occur or prove the other program points (and possibly the entire program) safe . To that purpose, null-pointer analysis of computer programs checks or infers non- null annotations for variables and object fields. With few notable exceptions, null-pointer analyses currently use run-time checks or are incorrect or only verify manually provided annotations. In this paper, we use abstract interpretation to build and prove correct a first, flow and context-sensitive static null-pointer analysis for Java bytecode (and hence Java) which infers non- null annotations. It is based on Boolean formulas, implemented with binary decision diagrams. For better precision, it identifies instance or static fields that remain always non- null after being initialised. Our experiments show this analysis faster and more precise than the correct null-pointer analysis by Hubert, Jensen and Pichardie. Moreover, our analysis deals with exceptions, which is not the case of most others; its formulation is theoretically clean and its implementation strong and scalable. We subsequently improve that analysis by using local reasoning about fields that are not always non- null , but happen to hold a non- null value when they are accessed . This is a frequent situation, since programmers typically check a field for non-nullness before its access. We conclude with an example of use of our analyses to infer null-pointer annotations which are more precise than those that other inference tools can achieve.

  • SEFM - Nullness Analysis in Boolean Form
    2008 Sixth IEEE International Conference on Software Engineering and Formal Methods, 2008
    Co-Authors: Fausto Spoto
    Abstract:

    Attempts to dereference null result in an exception or a Segmentation Fault. Hence it is important to know those program points where this might occur and prove the others (or the entire program) safe. Nullness analysis of computer programs checks or infers non-null annotations for variables and object fields. Most nullness analyses currently use run-time checks or are incorrect or only verify manual annotations. We use here abstract interpretation to build and prove correct a static nullness analysis for Java byte code which infers non-null annotations. It is based on Boolean formulas, implemented with binary decision diagrams. Our experiments show it faster and more precise than the correct nullness analysis by Hubert, Jensen and Pichardie. We deal with static fields and exceptions, which is not the case of most other analyses. We claim that the result is theoretically clean and the implementation strong and scalable.

  • Nullness Analysis in Boolean Form
    2008 Sixth IEEE International Conference on Software Engineering and Formal Methods, 2008
    Co-Authors: Fausto Spoto
    Abstract:

    Attempts to dereference null result in an exception or a Segmentation Fault. Hence it is important to know those program points where this might occur and prove the others (or the entire program) safe. Nullness analysis of computer programs checks or infers non-null annotations for variables and object fields. Most nullness analyses currently use run-time checks or are incorrect or only verify manual annotations. We use here abstract interpretation to build and prove correct a static nullness analysis for Java byte code which infers non-null annotations. It is based on Boolean formulas, implemented with binary decision diagrams. Our experiments show it faster and more precise than the correct nullness analysis by Hubert, Jensen and Pichardie. We deal with static fields and exceptions, which is not the case of most other analyses. We claim that the result is theoretically clean and the implementation strong and scalable.

Marcin Szymanek - One of the best experts on this subject based on the ideXlab platform.

  • Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
    Information Systems Architecture and Technology: Proceedings of 37th International Conference on Information Systems Architecture and Technology – ISA, 2017
    Co-Authors: Adam Czubak, Marcin Szymanek
    Abstract:

    Algorithmic complexity vulnerabilities are an opportunity for an adversary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully conducted attack which takes advantage of the worst case computational complexity of O(n2) of a hash table data structure used to store active sessions. The attack at hand is initiated from a network protected by an stateful firewall router feature to a remote server causing a DoS (Denial of Service) on an industry grade router. Our experimental results using a real life network topology show that by generating undetected low bandwidth but malicious network traffic causing collisions in the firewall’s hash table we cause the firewall to become unreachable or even announce a Segmentation Fault and reboot itself.

  • ISAT (2) - Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
    Advances in Intelligent Systems and Computing, 2016
    Co-Authors: Adam Czubak, Marcin Szymanek
    Abstract:

    Algorithmic complexity vulnerabilities are an opportunity for an adversary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully conducted attack which takes advantage of the worst case computational complexity of O(n 2) of a hash table data structure used to store active sessions. The attack at hand is initiated from a network protected by an stateful firewall router feature to a remote server causing a DoS (Denial of Service) on an industry grade router. Our experimental results using a real life network topology show that by generating undetected low bandwidth but malicious network traffic causing collisions in the firewall’s hash table we cause the firewall to become unreachable or even announce a Segmentation Fault and reboot itself.

Adam Czubak - One of the best experts on this subject based on the ideXlab platform.

  • Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
    Information Systems Architecture and Technology: Proceedings of 37th International Conference on Information Systems Architecture and Technology – ISA, 2017
    Co-Authors: Adam Czubak, Marcin Szymanek
    Abstract:

    Algorithmic complexity vulnerabilities are an opportunity for an adversary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully conducted attack which takes advantage of the worst case computational complexity of O(n2) of a hash table data structure used to store active sessions. The attack at hand is initiated from a network protected by an stateful firewall router feature to a remote server causing a DoS (Denial of Service) on an industry grade router. Our experimental results using a real life network topology show that by generating undetected low bandwidth but malicious network traffic causing collisions in the firewall’s hash table we cause the firewall to become unreachable or even announce a Segmentation Fault and reboot itself.

  • ISAT (2) - Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
    Advances in Intelligent Systems and Computing, 2016
    Co-Authors: Adam Czubak, Marcin Szymanek
    Abstract:

    Algorithmic complexity vulnerabilities are an opportunity for an adversary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully conducted attack which takes advantage of the worst case computational complexity of O(n 2) of a hash table data structure used to store active sessions. The attack at hand is initiated from a network protected by an stateful firewall router feature to a remote server causing a DoS (Denial of Service) on an industry grade router. Our experimental results using a real life network topology show that by generating undetected low bandwidth but malicious network traffic causing collisions in the firewall’s hash table we cause the firewall to become unreachable or even announce a Segmentation Fault and reboot itself.