scholarly journals Higher-Ranked Annotation Polymorphic Dependency Analysis

2020 ◽  
pp. 656-683 ◽  
Author(s):  
Fabian Thorand ◽  
Jurriaan Hage
Keyword(s):  
Static Analysis ◽  
Type System ◽  
Reconstruction Algorithm ◽  
Context Sensitivity ◽  
Functional Languages ◽  
Dependency Analysis ◽  
One Step ◽  
Type Reconstruction ◽  
Generic Analysis

AbstractThe precision of a static analysis can be improved by increasing the context-sensitivity of the analysis. In a type-based formulation of static analysis for functional languages this can be achieved by, e.g., introducing let-polyvariance or subtyping. In this paper we go one step further by defining a higher-ranked polyvariant type system so that even properties of lambda-bound identifiers can be generalized over. We do this for dependency analysis, a generic analysis that can be instantiated to a range of different analyses that in this way all can profit.We prove that our analysis is sound with respect to a call-by-name semantics and that it satisfies a so-called noninterference property. We provide a type reconstruction algorithm that we have proven to be terminating, and sound and complete with respect to its declarative specification. Our principled description can serve as a blueprint for making other analyses higher-ranked.

scholarly journals SART-Type Image Reconstruction from Overlapped Projections

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Hengyong Yu ◽  
Changguo Ji ◽  
Ge Wang
Keyword(s):  
Image Reconstruction ◽  
Reconstruction Algorithm ◽  
Reconstruction Technique ◽  
Algebraic Reconstruction Technique ◽  
Multiple Sources ◽  
X Ray ◽  
Type Reconstruction ◽  
Soft Threshold ◽  
Simultaneous Algebraic Reconstruction Technique ◽  
Data Acquisition Process

To maximize the time-integrated X-ray flux from multiple X-ray sources and shorten the data acquisition process, a promising way is to allow overlapped projections from multiple sources being simultaneously on without involving the source multiplexing technology. The most challenging task in this configuration is to perform image reconstruction effectively and efficiently from overlapped projections. Inspired by the single-source simultaneous algebraic reconstruction technique (SART), we hereby develop a multisource SART-type reconstruction algorithm regularized by a sparsity-oriented constraint in the soft-threshold filtering framework to reconstruct images from overlapped projections. Our numerical simulation results verify the correctness of the proposed algorithm and demonstrate the advantage of image reconstruction from overlapped projections.

scholarly journals Making pointer analysis more precise by unleashing the power of selective context sensitivity

2021 ◽  
Vol 5 (OOPSLA) ◽  
pp. 1-27
Author(s):  
Tian Tan ◽  
Yue Li ◽  
Xiaoxing Ma ◽  
Chang Xu ◽  
Yannis Smaragdakis
Keyword(s):  
State Of The Art ◽  
Context Sensitivity ◽  
The State ◽  
Pointer Analysis ◽  
Proof Of Concept ◽  
Context Sensitive ◽  
Java Programs ◽  
One Step ◽  
The Difference

Traditional context-sensitive pointer analysis is hard to scale for large and complex Java programs. To address this issue, a series of selective context-sensitivity approaches have been proposed and exhibit promising results. In this work, we move one step further towards producing highly-precise pointer analyses for hard-to-analyze Java programs by presenting the Unity-Relay framework, which takes selective context sensitivity to the next level. Briefly, Unity-Relay is a one-two punch: given a set of different selective context-sensitivity approaches, say S = S1, . . . , Sn, Unity-Relay first provides a mechanism (called Unity)to combine and maximize the precision of all components of S. When Unity fails to scale, Unity-Relay offers a scheme (called Relay) to pass and accumulate the precision from one approach Si in S to the next, Si+1, leading to an analysis that is more precise than all approaches in S. As a proof-of-concept, we instantiate Unity-Relay into a tool called Baton and extensively evaluate it on a set of hard-to-analyze Java programs, using general precision metrics and popular clients. Compared with the state of the art, Baton achieves the best precision for all metrics and clients for all evaluated programs. The difference in precision is often dramatic — up to 71% of alias pairs reported by previously-best algorithms are found to be spurious and eliminated.

Static Type Systems

2007 ◽  
pp. 302-357
Author(s):  
Pablo E. Martínez Lopez
Keyword(s):  
Static Analysis ◽  
Type System ◽  
Type Systems ◽  
Theory And Practice ◽  
Validation And Verification ◽  
Good Design ◽  
Design And Implementation ◽  
Verification Methods ◽  
Simple Language ◽  
Static Typing

Static type systems are fundamental tools used to determine properties of programs before execution. There exist several techniques for validation and verification of programs based on typing. Thus, type systems are important to know for the practicioner. When designing and implementing a technique based on typing systems, there is usually a gap between the formal tools used to specify it, and the actual implementations. This gap can be an obstacle for language designers and programmers. A better understanding of the features of a type system and how they are implemented can help enourmously to the good design and implementation of new and powerful verification methods based on type systems. This chapter addresses the problem of specifying and implementing a static type system for a simple language, but containing many of the subtleties found in bigger, mainstream languages. This contributes to the understanding of the techniques, thus bridging the gap between theory and practice. Additionally, the chapter contains a small survey of some of the existing developments in the static typing area and the static analysis based on typing.

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