280 research outputs found

    Economic effect of splitting a region: A case from the south of Chile

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    Treballs Finals del Màster d'Economia, Facultat d'Economia i Empresa, Universitat de Barcelona. Curs: 2021-2022, Tutor: Jordi Jofre-MonsenyThe economic impact of territorial reforms has been discussed in the literature, but mostly looking at amalgamations rather than de-amalgamations. Little is known about the impact of territorial splits and even less in a centralized and emerging country. This paper aim to fill this gap by analyzing the specific case of the Los Rios region, who was splinted from Los Lagos region in the south of Chile. By using a synthetic control approach, a difference in differences and event studies, we estimate the causal effect of such reform over GDP, private sales, and employment on the affected regions, including the effect of the new administrative status for the city of Valdivia who became regional capital. Once we accounted for all sources of external shocks, we did not find any impact of the division on the regions of Los Lagos and Los Rios and no effect of the new administrative status for Valdivia. We believe these results are very important as illustrate that policies aimed to splits regions or relocate the capital status to promote growth should consider the context and the scope of competences of the subnational governments

    AnICA: Analyzing Inconsistencies in Microarchitectural Code Analyzers

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    Microarchitectural code analyzers, i.e., tools that estimate the throughput of machine code basic blocks, are important utensils in the tool belt of performance engineers. Recent tools like llvm-mca, uiCA, and Ithemal use a variety of techniques and different models for their throughput predictions. When put to the test, it is common to see these state-of-the-art tools give very different results. These inconsistencies are either errors, or they point to different and rarely documented assumptions made by the tool designers. In this paper, we present AnICA, a tool taking inspiration from differential testing and abstract interpretation to systematically analyze inconsistencies among these code analyzers. Our evaluation shows that AnICA can summarize thousands of inconsistencies in a few dozen descriptions that directly lead to high-level insights into the different behavior of the tools. In several case studies, we further demonstrate how AnICA automatically finds and characterizes known and unknown bugs in llvm-mca, as well as a quirk in AMD's Zen microarchitectures.Comment: To appear in Proceedings of the ACM on Programming Languages (PACMPL), Vol. 6, No. OOPSLA

    PICO: A Presburger In-bounds Check Optimization for Compiler-based Memory Safety Instrumentations

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    Memory safety violations such as buffer overflows are a threat to security to this day. A common solution to ensure memory safety for C is code instrumentation. However, this often causes high execution-time overhead and is therefore rarely used in production. Static analyses can reduce this overhead by proving some memory accesses in bounds at compile time. In practice, however, static analyses may fail to verify in-bounds accesses due to over-approximation. Therefore, it is important to additionally optimize the checks that reside in the program. In this article, we present PICO, an approach to eliminate and replace in-bounds checks. PICO exactly captures the spatial memory safety of accesses using Presburger formulas to either verify them statically or substitute existing checks with more efficient ones. Thereby, PICO can generate checks of which each covers multiple accesses and place them at infrequently executed locations. We evaluate our LLVM-based PICO prototype with the well-known SoftBound instrumentation on SPEC benchmarks commonly used in related work. PICO reduces the execution-time overhead introduced by SoftBound by 36% on average (and the code-size overhead by 24%). Our evaluation shows that the impact of substituting checks dominates that of removing provably redundant checks

    Der Druckverband bei Ophthalmoblennorrhoea Neonatorum : Inaugural-Dissertation

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