Partial (In)Completeness in abstract interpretation: limiting the imprecision in program analysis

Imprecision is inherent in any decidable (sound) approximation of undecidable program properties. In abstract interpretation this corresponds to the release of false alarms, e.g., when it is used for program analysis and program verification. As all alarming systems, a program analysis tool is credible when few false alarms are reported. As a consequence, we have to live together with false alarms, but also we need methods to control them. As for all approximation methods, also for abstract interpretation we need to estimate the accumulated imprecision during program analysis. In this paper we introduce a theory for estimating the error propagation in abstract interpretation, and hence in program analysis. We enrich abstract domains with a weakening of a metric distance. This enriched structure keeps coherence between the standard partial order relating approximated objects by their relative precision and the effective error made in this approximation. An abstract interpretation is precise when it is complete. We introduce the notion of partial completeness as a weakening of precision. In partial completeness the abstract interpreter may produce a bounded number of false alarms. We prove the key recursive properties of the class of programs for which an abstract interpreter is partially complete with a given bound of imprecision. Then, we introduce a proof system for estimating an upper bound of the error accumulated by the abstract interpreter during program analysis. Our framework is general enough to be instantiated to most known metrics for abstract domains.

Semantic network of the German preposition hinter

The present study sets out to construct a semantic network for the German preposition hinter (‘behind’) based on the theoretical framework of “principled polysemy”. The analysis regarding the cognitive and pragmatic aspects motivating the meaning extensions of hinter attempts to highlight the importance of varying construal patterns and vantage points as well as the role of real-world knowledge. By means of corpus data, I intend to present six senses of the preposition hinter, hinting at the polysemous nature of prepositions more generally. Furthermore, the theory of conceptual metaphor is applied to account for metaphorical extensions of hinter to more abstract domains of embodied experience.

A Fresh Look at Zones and Octagons

Zones and Octagons are popular abstract domains for static program analysis. They enable the automated discovery of simple numerical relations that hold between pairs of program variables. Both domains are well understood mathematically but the detailed implementation of static analyses based on these domains poses many interesting algorithmic challenges. In this article, we study the two abstract domains, their implementation and use. Utilizing improved data structures and algorithms for the manipulation of graphs that represent difference-bound constraints, we present fast implementations of both abstract domains, built around a common infrastructure. We compare the performance of these implementations against alternative approaches offering the same precision. We quantify the differences in performance by measuring their speed and precision on standard benchmarks. We also assess, in the context of software verification, the extent to which the improved precision translates to better verification outcomes. Experiments demonstrate that our new implementations improve the state of the art for both Zones and Octagons significantly.

A Cognitive Analysis of Poems in A Dream of Red Mansions from the Perspective of Image Schema

This paper adopts a cognitive perspective in the analysis of various image schemas in the novel A Dream of Red Mansions, one of the most influential classical masterpieces in Chinese literature. Two poems from the novel are interpreted from the perspective of link schema, container schema, up-down schema, part-whole schema, and source-path-goal schema, to reveal the personalities, values and life philosophies of the two female protagonists. The contrast between the pessimism and melancholy of Daiyu and the optimism and aspiration of Baochai demonstrates the author’s understanding of that time and society, especially the status and fate of females. The analysis illustrates that image schemas, which involves bodily experience and metaphorical projection from concrete to abstract domains, can surpass language boundaries, reveal emotions and themes, and shed light on cross-cultural studies of literature.

Gambaran Fungsi Kognitif Pasien Pasca Stroke

Stroke or brain attack occurs directly and its incidence is still very high until now. It is reported that two-thirds of stroke patients suffered from cognitive impairment leading to dementia within three months after stroke that can interfere with one’s daily activities if left untreated. This study was aimed to obtain the description of cognitive function in post-stroke patients. This was a literature review study using three databases, as follows: Goggle Scholar, Pubmed, and Clinical Key, and the keywords were cognitive impairment, cognitive decline, post-stroke, and MoCA. There were 10 literatures that met the inclusion and exclusion criteria. The results showed that many post-stroke patients showed cognitive function decline in the visuospatial/executive, memory, language, attention, and abstract domains. Cognitive impairment occured mostly in male patients, age 60 years and over, low education, ischemic stroke, left hemisphere lesion, with a history of hypertension. In conclusion, there is a relationship between post-stroke cognitive impairment and the location of lesion, age, and education level, albeit, there was no relationship between the cognitive impairment and gender as well as diabetes mellitus.Keywords: cognitive impairment, post-stroke, MoCA Abstrak: Stroke menyerang otak secara langsung dengan angka kejadian yang masih sangat tinggi sampai saat ini. Dua pertiga pasien stroke dilaporkan mengalami gangguan fungsi kognitif yang berujung pada demensia dalam tiga bulan pasca stroke serta dapat mengganggu aktivitas sehari-hari bila dibiarkan. Penelitian ini bertujuan untuk mendapatkan gambaran fungsi kognitif pasien pasca stroke. Jenis penelitian ialah literature review, dengan pencarian literatur pada tiga database yaitu Goggle Scholar, Pubmed, dan Clinical Key. Kata kunci yang digunakan ialah penurunan fungsi kognitif, pasca stroke, dan MoCA. Hasil seleksi mendapatkan 10 literatur yang memenuhi kriteria inklusi dan eksklusi. Hasil penelitian menunjukkan bahwa pada pasien pasca stroke sering terjadi penurunan fungsi kognitif dengan domain visuospasial/eksekutif, memori, bahasa, atensi, dan abstrak yang paling sering terganggu. Penurunan fungsi kognitif banyak ditemukan pada pasien laki-laki, usia 60 tahun ke atas, jenjang pendidikan rendah, stroke iskemik, lesi hemisfer kiri, dengan riwayat hipertensi. Simpulan penelitian ini ialah adanya hubungan antara penurunan fungsi kognitif dengan lokasi lesi, usia, dan jenjang pendidikan namun tidak terdapat hubungan dengan jenis kelamin dan diabetes melitus.Kata kunci: gangguan kognitif, pasca stroke, MoCA

Data Flow Analysis of Asynchronous Systems using Infinite Abstract Domains

Asynchronous message-passing systems are employed frequently to implement distributed mechanisms, protocols, and processes. This paper addresses the problem of precise data flow analysis for such systems. To obtain good precision, data flow analysis needs to somehow skip execution paths that read more messages than the number of messages sent so far in the path, as such paths are infeasible at run time. Existing data flow analysis techniques do elide a subset of such infeasible paths, but have the restriction that they admit only finite abstract analysis domains. In this paper we propose a generalization of these approaches to admit infinite abstract analysis domains, as such domains are commonly used in practice to obtain high precision. We have implemented our approach, and have analyzed its performance on a set of 14 benchmarks. On these benchmarks our tool obtains significantly higher precision compared to a baseline approach that does not elide any infeasible paths and to another baseline that elides infeasible paths but admits only finite abstract domains.