Bounded Verification of Multi-threaded Programs via Lazy Sequentialization

Bounded verification techniques such as bounded model checking (BMC) have successfully been used for many practical program analysis problems, but concurrency still poses a challenge. Here, we describe a new approach to BMC of sequentially consistent imperative programs that use POSIX threads. We first translate the multi-threaded program into a nondeterministic sequential program that preserves reachability for all round-robin schedules with a given bound on the number of rounds. We then reuse existing high-performance BMC tools as backends for the sequential verification problem. Our translation is carefully designed to introduce very small memory overheads and very few sources of nondeterminism, so it produces tight SAT/SMT formulae, and is thus very effective in practice: Our Lazy-CSeq tool implementing this translation for the C programming language won several gold and silver medals in the concurrency category of the Software Verification Competitions (SV-COMP) 2014–2021 and was able to find errors in programs where all other techniques (including testing) failed. In this article, we give a detailed description of our translation and prove its correctness, sketch its implementation using the CSeq framework, and report on a detailed evaluation and comparison of our approach.

Verified compilation of C programs with a nominal memory model

Memory models play an important role in verified compilation of imperative programming languages. A representative one is the block-based memory model of CompCert---the state-of-the-art verified C compiler. Despite its success, the abstraction over memory space provided by CompCert's memory model is still primitive and inflexible. In essence, it uses a fixed representation for identifying memory blocks in a global memory space and uses a globally shared state for distinguishing between used and unused blocks. Therefore, any reasoning about memory must work uniformly for the global memory; it is impossible to individually reason about different sub-regions of memory (i.e., the stack and global definitions). This not only incurs unnecessary complexity in compiler verification, but also poses significant difficulty for supporting verified compilation of open or concurrent programs which need to work with contextual memory, as manifested in many previous extensions of CompCert. To remove the above limitations, we propose an enhancement to the block-based memory model based on nominal techniques; we call it the nominal memory model. By adopting the key concepts of nominal techniques such as atomic names and supports to model the memory space, we are able to 1) generalize the representation of memory blocks to any types satisfying the properties of atomic names and 2) remove the global constraints for managing memory blocks, enabling flexible memory structures for open and concurrent programs. To demonstrate the effectiveness of the nominal memory model, we develop a series of extensions of CompCert based on it. These extensions show that the nominal memory model 1) supports a general framework for verified compilation of C programs, 2) enables intuitive reasoning of compiler transformations on partial memory; and 3) enables modular reasoning about programs working with contextual memory. We also demonstrate that these extensions require limited changes to the original CompCert, making the verification techniques based on the nominal memory model easy to adopt.

Layered and object-based game semantics

Large-scale software verification relies critically on the use of compositional languages, semantic models, specifications, and verification techniques. Recent work on certified abstraction layers synthesizes game semantics, the refinement calculus, and algebraic effects to enable the composition of heterogeneous components into larger certified systems. However, in existing models of certified abstraction layers, compositionality is restricted by the lack of encapsulation of state. In this paper, we present a novel game model for certified abstraction layers where the semantics of layer interfaces and implementations are defined solely based on their observable behaviors. Our key idea is to leverage Reddy's pioneer work on modeling the semantics of imperative languages not as functions on global states but as objects with their observable behaviors. We show that a layer interface can be modeled as an object type (i.e., a layer signature) plus an object strategy. A layer implementation is then essentially a regular map, in the sense of Reddy, from an object with the underlay signature to that with the overlay signature. A layer implementation is certified when its composition with the underlay object strategy implements the overlay object strategy. We also describe an extension that allows for non-determinism in layer interfaces. After formulating layer implementations as regular maps between object spaces, we move to concurrency and design a notion of concurrent object space, where sequential traces may be identified modulo permutation of independent operations. We show how to express protected shared object concurrency, and a ticket lock implementation, in a simple model based on regular maps between concurrent object spaces.

SAFAR BATH IN THE VALUE PERSPECTIVE OF ISLAMIC EDUCATION IN THE ATINGGOLA COMMUNITY

The purpose of this research is to find out; The value of Islamic education and traditional values contained in the Mandi Safardi procession, Jin City Village, Atinggola District, North Gorontalo Regency.The method used is a qualitative method, the data is obtained through observation, interviews, and documentation. The data were then analyzed using reduction, display, and verification techniques, while the validity of the data was obtained by using triangulation techniques with methods and sources.The results of this study indicate that the Safar Bathing Tradition is believed to have existed since their ancestors first occupied the Jin City Village area. The Safar Bathing tradition carried out by the Jin City Village community contains Islamic educational values, namely: Worship Values, Moral Values, Moral Values, and Aqidah Values, 4) The Safar Bathing Tradition is maintained and passed down from generation to generation by the Jin City Village community. can be seen as an expressive symbol of the Jin City Village community Inspired by constitutive (religious) symbols that have a corelative-integrative and dynamic relationshipSuggestions from this research include; The Mandi Safar tradition as an ancestral cultural heritage should continue to be preserved for future generations by not eliminating the local Indonesian religious and cultural values contained in it as a medium for introducing ancestral traditions that are full of moral and religious values without ignoring the shari'ah. Islam in practice.

Open and Branching Behavioral Synthesis with Scenario Clauses

The Software Engineering community has identified behavioral specification as one of the main challenges to be addressed for the transference of formal verification techniques such as model checking. In particular, expressivity of the specification language is a key factor, especially when dealing with Open Systems and controllability of events and branching time behavior reasoning. In this work, we propose the Feather Weight Visual Scenarios (FVS) language as an appealing declarative and formal verification tool to specify and synthesize the expected behavior of systems. FVS can express linear and branching properties in closed and Open systems. The validity of our approach is proved by employing FVS in complex, complete, and industrial relevant case studies, showing the flexibility and expressive power of FVS, which constitute the crucial features that distinguish our approach.

Verification and usability of location specific medium range weather forecast for Kullu valley

Weather plays a crucial role in agriculture. Precipitation, temperature, humidity, wind speed and direction, drying conditions, dry and wet spells are the most important weather elements information about whom could play a significant role in farm planning and operations. Inclement weather events like drought and floods, cold and heat waves, hails, squalls, tropical storms severely affect the production. Occurrences of erratic weather are beyond human control. It is possible to adapt or mitigate their malevolent effect to some extend if the occurrence of the events is predicted well in advance and farmers are suitably advised to take ameliorative measures. Attempts were made to verify the weather forecasts received on every Tuesday and Friday from NCMRWF/IMD. The verification analysis was carried out on weekly, seasonal and annual basis using various verification techniques, viz., Ratio Score (RS), Critical Success Index (CSI), Heidke Skill Score (HSS), Hanssen and Kuipers Score (HK), Root Mean Square Error (RMSE), usability analysis and correlation approach during 2000-01 to 2009-10. The analysis depicted that ratio score on yearly basis was highest (74.6) during 2005-06 followed by 2004-05 (72.9) and 2003-04 (72.7). The value of H.K. score ranged between 24 and 42. The forecast found within quite usability range for most of the parameters but improvements are still possible. The correlation analysis showed that there was high correlation between observed and predicted values over the years. Hence, the forecast was found widely applicable among different user groups.

STRATEGI POLA ASUH KELUARGA SEBAGAI PENDAMPING ANAK PADA PEMBELAJARAN DARING DI MASA PANDEMI COVID-19

This study titled "Parenting styles in children's online learning during the Covid-19 Pandemic "(Case Study of Kelanir Village, Seteluk, West Sumbawa Regency). Kelanir village is a remote village located behind the hills. Therefore, it is hard to get a good signal. This study aims to examine the parenting styles in children’s online learning in the era of covid-19. This study used the social action theory by Max Weber (Rational-purposeful action, value-rational action, affective action and traditional action). The method of this study was the qualitative case study. The Participant informants were parents who have high school children. The data was collected using in-depth interviews, observations and documentation and was analyzed using data reduction, data display and conclusion drawing or verification techniques. The results showed a change in parenting style. Before the covid-19 pandemic, parents applied three parenting styles which are permissive, authoritarian and democratic. However, parents changed their parenting style to authoritarian and democratic parenting styles only in the online learning process during the covid-19 pandemic. The parenting challenges during online learning are signal difficulties, lack of knowledge, and time problems.

Pediatric glioblastoma treated with concurrent radiotherapy and adjuvant Temozolomide: A case study of the treatment of pediatric GBM by the technique of volumetric modulated arc therapy

Introduction: Glioblastoma in children (pGBM) occurs somewhat less frequently than in adults. Pediatric pGBMs have a different molecular profile than GBM for adults. The aim of the presentation of this case is the possibility of the effectiveness of the GBM radiation method and the evaluation of magnetic resonance imaging, and the monitoring of the treatment outcome of the patient.Material and methods: The case study is of the retrospective-prospective type. Medical documentation, magnetic resonance imaging, and chronologically monitored evaluation of the findings from November 2018 to August 2021 were used to present the study. The postoperative course was analyzed, as well as the effect of concurrent chemoradiotherapy, VMAT radiotherapy and adjuvant chemotherapy with Temozolomide in a patient aged 4 years and 6 months, comparing treatment outcome with median and overall survival in glioblastoma.Results: The pediatric patient after being diagnosed with high-grade glioma in 2018 is so far in very good general condition, without signs of physical and psycho-social defects, which compared to the scientifically proven median of survival indicates a good therapeutic effect. Volumetrically modulated arc radiotherapy with the use of modern IGRT verification techniques and with the use of chemotherapy with Temozoloimod, has proven to be a still effective oncological method treatment of GBM. For the final outcome of the disease and the effect of therapeutic modalities, the patient's condition and evaluation of magnetic resonance imaging will be monitored. The result supports further research into this therapeutic regimen.Conclusion: Glioblastoma is a very aggressive tumor, which occurs somewhat less frequently in the pediatric population than in adults, but is a very fatal disease. Surgical resection followed by concurrent chemoradiotherapy, with adjuvant Temozolomide is still the method of choice in the treatment of glioblastoma.

Advances in mass cytometry and its applicability to digital pathology in clinical-translational cancer research

The development and subsequent adaptation of mass cytometry for the histological analysis of tissue sections has allowed the simultaneous spatial characterization of multiple components. This is useful to find the correlation between the genotypic and phenotypic profile of tumor cells and their environment in clinical-translational studies. In this revision, we provide an overview of the most relevant hallmarks in the development, implementation and application of multiplexed imaging in the study of cancer and other conditions. A special focus is placed on studies based on imaging mass cytometry (IMC) and multiplexed ion beam imaging (MIBI). The purpose of this review is to help our readers become familiar with the verification techniques employed on this tool and outline the multiple applications reported in the literature. This review will also provide guidance on the use of IMC or MIBI in any field of biomedical research.