Equivalent Programming Research Articles

Program Equivalence in the Erlang Actor Model

This paper presents the formal semantics of concurrency in Core Erlang, an intermediate language for Erlang, along with a notion of program equivalence (based on barbed bisimulation) that is able to model equivalence between programs that have different communication structures but the same observable behaviour. The novelty in our formalisation is its extent: it includes semantics for messages and exit and link signals, in addition to most of Core Erlang’s sequential features. Furthermore, unlike previous studies, this work formalises message receipt using primitive operations, consistent with the standard as of Erlang/OTP 23. In this novel formalisation, we show some generally applicable program equivalences (such as process identifier renaming and silent evaluation) and present a practical case study featuring the equivalence of sequential and concurrent list processing.

Analisis Kompetensi Andragogi Tutor Pendidikan Kesetaraan dalam Pembelajaran di Sanggar Kegiatan Belajar (SKB) Kota Medan

This research aims to analyze the competence of equal education tutors in the Medan City Community Learning Activity Studio (SKB). The type of research used is qualitative descriptive research. There were 3 subjects in the research, namely tutors in the equivalency program. The data collection techniques used were observation, interviews and documentation. Data analysis techniques are data reduction, data presentation and drawing conclusions. The validity of the research includes source triangulation and technique triangulation. The research results show that tutors have shown significant efforts in understanding the characteristics and needs of students by approaching them directly and identifying individual habits and needs. Mastery of educational principles can also be seen through the tutor's efforts to integrate educational principles in learning by creating an active and interesting class atmosphere. In terms of curriculum development, tutors collaborate with external parties to ensure the relevance and effectiveness of the curriculum according to student needs, by paying attention to basic principles such as relevance and efficiency. The learning strategies implemented, including discussion methods and the use of simple language, succeeded in increasing students' understanding. Apart from that, tutors are able to create interactive, fun and challenging learning situations. Mastery of conventional learning media is good, but use of information and communication technology (ICT) varies, with some tutors facing technical and infrastructure obstacles. Finally, assessments are carried out using various tools, both tests and non-tests, to ensure fair and objective learning outcomes.

High School Equivalency Program (ED)

High School Equivalency Program (ED)

The Flinders University/TAFE SA Bachelor of Creative Arts dual award model: A case study

This study aims to evaluate the effectiveness of the Bachelor of Creative Arts (BCA), a dual award degree offered jointly by Flinders University and TAFE SA. It first sets the rationale for the award while placing it in the Australian educational context, comparing it to equivalent programs offered at other institutions. It then provides an insight into the characteristics of a cohort of students. To achieve this, the study analyses a range of key quantitative metrics including demographics, enrolment numbers, attrition, student experience surveys and grade distributions to determine the cohort’s profile. Additionally, the study seeks information from recent graduates already in the workforce to establish if the BCA provides the skills leading to successful employment. This study reveals a mixed picture of the BCA’s success. While degree completion and student satisfaction are high, alumni are not all convinced that having a university degree provides a significant advantage for the job market as opposed to only having a TAFE qualification. Finally, the study offers recommendations to address these issues and improve the overall student experience as well as enhance their employment prospects.

Equivalence and Similarity Refutation for Probabilistic Programs

We consider the problems of statically refuting equivalence and similarity of output distributions defined by a pair of probabilistic programs. Equivalence and similarity are two fundamental relational properties of probabilistic programs that are essential for their correctness both in implementation and in compilation. In this work, we present a new method for static equivalence and similarity refutation. Our method refutes equivalence and similarity by computing a function over program outputs whose expected value with respect to the output distributions of two programs is different. The function is computed simultaneously with an upper expectation supermartingale and a lower expectation submartingale for the two programs, which we show to together provide a formal certificate for refuting equivalence and similarity. To the best of our knowledge, our method is the first approach to relational program analysis to offer the combination of the following desirable features: (1) it is fully automated, (2) it is applicable to infinite-state probabilistic programs, and (3) it provides formal guarantees on the correctness of its results. We implement a prototype of our method and our experiments demonstrate the effectiveness of our method to refute equivalence and similarity for a number of examples collected from the literature.

Project Impact: A Public Community College Campus–Based Support and Reentry Program for Justice-Impacted Students in New York City

Background: Between 70 million and 100 million Americans have a record of interaction with the criminal legal system, a group facing stigma and discrimination in civic participation, housing, employment, and education. Justice-impacted people face collateral consequences in the community, making reentry programs essential to success at reintegration. Focus of Study: Project Impact (PI) at the Borough of Manhattan Community College/City University of New York (BMCC/CUNY) supports students impacted by the criminal legal system. PI provides direct services to justice-impacted students through an extensive peer mentoring program and a high school equivalency program, and by offering college credit–bearing courses to students presently incarcerated in partnership with John Jay College’s Prison-to-College Pipeline. PI defines “justice impacted” expansively as students who have been formerly incarcerated, have family who have been incarcerated or arrested, have had issues in family court, or in any other way have been significantly affected by the criminal legal system. Research Design/Conclusions: This evaluation provides unequivocal evidence of the strong, positive impact that PI is making, serving as a rare campus-based reentry program within a community college in New York City.

Towards determinism in PDL: relations and proof theory

Abstract Guarded Kleene Algebra with Tests (GKAT) was presented as a fragment of KAT to abstract imperative programming languages, where only if-then-else and while-do statements are allowed in the language. The loss of expressiveness is, nevertheless, compensated by a clear advantage over KAT: it allows almost linear decidability of program equivalence. In this work, we give the first step to optimizing the complexity of dynamic logic equivalence, which is EXPTIME-complete in propositional dynamic logic (PDL). First, and based on strict deterministic PDL, we present guarded propositional dynamic logic (GPDL), a fragment of PDL where programs correspond to GKAT terms. It comes embedded, as expected, with a semantics over relational models and a sound axiomatisation. Then, we present a Natural Deduction system for GPDL, proving its soundness and completeness, concerning the axiomatisation. Based on Smolka et al. (2019, Proceedings of the ACM Programming Language 4), we obtain the main result of this work—the equivalence of GPDL programs can be established in almost linear time.

PASDA: A partition-based semantic differencing approach with best effort classification of undecided cases

Equivalence checking is used to verify whether two programs produce equivalent outputs when given equivalent inputs. Research in this field mainly focused on improving equivalence checking accuracy and runtime performance. However, for program pairs that cannot be proven to be either equivalent or non-equivalent, existing approaches only report a classification result of unknown, which provides no information regarding the programs’ non-/equivalence.In this paper, we introduce PASDA, our partition-based semantic differencing approach with best effort classification of undecided cases. While PASDA aims to formally prove non-/equivalence of analyzed program pairs using a variant of differential symbolic execution, its main novelty lies in its handling of cases for which no formal non-/equivalence proof can be found. For such cases, PASDA provides a best effort equivalence classification based on a set of classification heuristics.We evaluated PASDA with an existing benchmark consisting of 141 non-/equivalent program pairs. PASDA correctly classified 61%–74% of these cases at timeouts from 10 s to 3600 s. Thus, PASDA achieved equivalence checking accuracies that are 3%–7% higher than the best results achieved by three existing tools. Furthermore, PASDA’s best effort classifications were correct for 70%–75% of equivalent and 55%–85% of non-equivalent cases across the different timeouts.

An uncertainty theory based tri-objective behavioral portfolio selection model with loss aversion and reference level using a modified evolutionary root system growth algorithm

The outbreak of uncertain events, e.g., financial crisis, regional conflict and abrupt contagion, has a significant impact on residents’ income. Hence, the wealth management and portfolio selection become more and more important. In addition, the behavioral finance believes that decision-making process of the investors not only depend on utility maximization, but also on who to compare with. It differs from the traditional finance based on rational cognitive acquiring and decision-making of agents, in this paper, we consider both investment uncertainty and investment utility with reference level for portfolio selection. First, we introduce the uncertainty theory and loss aversion utility with reference level based on behavioral finance. Then we study an uncertain multi-period portfolio selection problem. Moreover, we formulate an uncertain behavioral portfolio selection model with three objective functions for which we propose an equivalent program consisting of a main model and two auxiliary models for tri-objective optimization model. Thereafter, we use a modified evolutionary root system growth algorithm to solve the transformed models. Finally, a numerical simulation allows to show the practicability of proposed models and validity of modified algorithm.

A Formalisation of Core Erlang, a Concurrent Actor Language

In order to reason about the behaviour of programs described in a programming language, a mathematically rigorous definition of that language is needed. In this paper, we present a machine-checked formalisation of concurrent Core Erlang (a subset of Erlang) based on our previous formalisations of its sequential sublanguage. We define a modular, frame stack semantics, show how program evaluation is carried out with it, and prove a number of properties (e.g. determinism, confluence). Finally, we define program equivalence based on bisimulations and prove that side-effect-free evaluation is a bisimulation. This research is part of a wider project that aims to verify refactorings to prove that particular program code transformations preserve program behaviour.

Indistinguishability Obfuscation from Well-Founded Assumptions

At least since the initial public proposal of public-key cryptography based on computational hardness conjectures, cryptographers have contemplated the possibility of a "one-way compiler" that translates computer programs into "incomprehensible" but equivalent forms. And yet, the search for such a "one-way compiler" remained elusive for decades. We examine a formalization of this concept with the notion of indistinguishability obfuscation (iO) . Roughly speaking, iO requires that the compiled versions of any two equivalent programs (with the same size and running time) be indistinguishable from any efficient adversary. Finally, we show how to construct iO in such a way that we can prove the security of our iO scheme based on well-studied computational hardness conjectures in cryptography.

Probabilistic Programming with Exact Conditions

We spell out the paradigm of exact conditioning as an intuitive and powerful way of conditioning on observations in probabilistic programs. This is contrasted with likelihood-based scoring known from languages such as Stan . We study exact conditioning in the cases of discrete and Gaussian probability, presenting prototypical languages for each case and giving semantics to them. We make use of categorical probability (namely Markov and CD categories) to give a general account of exact conditioning, which avoids limits and measure theory, instead focusing on restructuring dataflow and program equations. The correspondence between such categories and a class of programming languages is made precise by defining the internal language of a CD category.

Matematik Destekli Programlamaya Giriş Eğitiminin Bilgi İşlemsel Düşünme Üzerindeki Etkisi

The study aims to research the effect of an introductory programming course equipped with math-based programming activities on computational thinking skills and self-efficacy. A static-groups pre-test post-test quasi-experimental design was used. One hundred seventy-six 6th-grade students of a public school participated in the study. Eighty-nine of these students were in the experimental group, and 87 were in the control group. While the students in the experimental group received introductory programming education with Math-supported activities, the students in the control group received programming education with traditional course activities. Equivalent programming activities were carried out in both groups. Data were collected via two scales; Computational Thinking Test and Self-Efficacy Perception Scale for Computational Thinking Skills. After the study was completed, post-test scores were analyzed by ANCOVA analysis by controlling pre-test scores. The findings indicated no difference between the two groups regarding computational thinking test performance. Similarly, no conclusion stated a difference between the groups’ perceptions of self-efficacy of computational thinking. According to these results, evaluations regarding the positive and negative effects of using mathematics and programming together in an elementary programming education, which is thought to be related to Computational Thinking Skills, were reached at the skills of the study.

Asynchronous Probabilistic Couplings in Higher-Order Separation Logic

Probabilistic couplings are the foundation for many probabilistic relational program logics and arise when relating random sampling statements across two programs. In relational program logics, this manifests as dedicated coupling rules that, e.g., say we may reason as if two sampling statements return the same value. However, this approach fundamentally requires aligning or "synchronizing" the sampling statements of the two programs which is not always possible. In this paper, we develop Clutch, a higher-order probabilistic relational separation logic that addresses this issue by supporting asynchronous probabilistic couplings. We use Clutch to develop a logical step-indexed logical relation to reason about contextual refinement and equivalence of higher-order programs written in a rich language with a probabilistic choice operator, higher-order local state, and impredicative polymorphism. Finally, we demonstrate our approach on a number of case studies. All the results that appear in the paper have been formalized in the Coq proof assistant using the Coquelicot library and the Iris separation logic framework.

Internalizing Indistinguishability with Dependent Types

In type systems with dependency tracking, programmers can assign an ordered set of levels to computations and prevent information flow from high-level computations to the low-level ones. The key notion in such systems is indistinguishability : a definition of program equivalence that takes into account the parts of the program that an observer may depend on. In this paper, we investigate the use of dependency tracking in the context of dependently-typed languages. We present the Dependent Calculus of Indistinguishability (DCOI), a system that adopts indistinguishability as the definition of equality used by the type checker. DCOI also internalizes that relation as an observer-indexed propositional equality type, so that programmers may reason about indistinguishability within the language. Our design generalizes and extends prior systems that combine dependency tracking with dependent types and is the first to support conversion and propositional equality at arbitrary observer levels. We have proven type soundness and noninterference theorems for DCOI and have developed a prototype implementation of its type checker.

The Flinders University/TAFE SA Bachelor of Creative Arts dual award model: A case study

This study aims to evaluate the effectiveness of the Bachelor of Creative Arts (BCA), a dual award degree offered jointly by Flinders University and TAFE SA. It first sets the rationale for the award while placing it in the Australian educational context, comparing it to equivalent programs offered at other institutions. It then provides an insight into the characteristics of a cohort of students. To achieve this, the study analyses a range of key quantitative metrics including demographics, enrolment numbers, attrition, student experience surveys and grade distributions to determine the cohort’s profile. Additionally, the study seeks information from recent graduates already in the workforce to establish if the BCA provides the skills leading to successful employment. This study reveals a mixed picture of the BCA’s success. While degree completion and student satisfaction are high, alumni are not all convinced that having a university degree provides a significant advantage for the job market as opposed to only having a TAFE qualification. Finally, the study offers recommendations to address these issues and improve the overall student experience as well as enhance their employment prospects.

Notions of Non-Mainstream Educational Provision: Understanding the Indonesia Equivalency Programs Among Established Alternative Education Throughout the World

This article presents the overview of literature regarding the notions of non-mainstream education provision. The main purpose is to provide an overview of how the Indonesia Equivalency Program as an alternative education links to similar systems of education provision around the world. The literature shows variations in the terminology of non-mainstream education for out-of-school youth used interchangeably among countries. The notions of non-formal education, alternative education and second change education are often used and relevant in order to established well-defined axes along which to situate thinking about Indonesia Equivalency Programs. Through alternative education that offers democratic educational experience, the Indonesia Equivalency Programs is an alternative education system, based on the belief that people can make their own choice regarding mainstream or alternative schooling. The Equivalency Programs fits with the notion as a second chance education to caters students who failed in their first attempt. The aims of participating can be varying, from seeking remedial support to help in getting employment, or pursuing lifelong learning.

Program equivalence in a typed probabilistic call-by-need functional language

We extend a call-by-need variant of PCF with a binary probabilistic fair choice operator, which makes a lazy and typed variant of probabilistic functional programming. We define a contextual equivalence that respects the expected convergence of expressions and prove a corresponding context lemma. This enables us to show correctness of several program transformations with respect to contextual equivalence. Distribution-equivalence of expressions of numeric type is introduced. While the notion of contextual equivalence stems from program semantics, the notion of distribution equivalence is a direct description of the stochastic model. Our main result is that both notions are compatible: We show that for closed expressions of numeric type contextual equivalence and distribution-equivalence coincide. This provides a strong and often operationally feasible criterion for contextual equivalence of expressions and programs.

Optimal GED Student Recruitment: Perceptions of Program Directors

Much is unknown about those who do not finish high school and there is a need to understand who enters and completes alternative high school completion programs, such as the HiSet (High School Equivalency Test), GED (General Education Development Test), or growing number of state sponsored high school equivalency programs. The purpose for conducting the study was to describe the perceptions of adult education program coordinators about how to best categorize potential high school credential alternative completers. Using a phenomenological framework and semi-structured interviews, 12 adult education program administrators were interviewed about who enrolls in and completes their programs. A thematic analysis of these responses indicated distinct categories of individuals including opportunists (those looking for better opportunities), exceptionals (those with exceptionalities such as a disability that prevented the individual from completing a traditional high school diploma), immigrants (those validating learning in another country or language learners), and those who have been reformed in some way (eg, those with a history of difficulty with legal situations). By identifying these initial categories of adult learners taking part in high school equivalency programs, recruitment efforts as well as the programs themselves might be better structured to correspond to learner needs.

Operationally-based program equivalence proofs using LCTRSs

We propose an operationally-based framework for deductive proofs of program equivalence. It is based on encoding the language semantics as logically constrained term rewriting systems (LCTRSs) and the two programs as terms. As a novelty of our method, we show that it enables relational reasoning about programs in various settings, which are encoded in the operational semantics. For example, we show how our method can be used to prove programs that are equivalent when considering an unbounded stack, but where the equivalence fails to hold if the stack is bounded. We also show how to formalize read-sets and write-sets of symbolic expressions and statements by extending the operational semantics in a conservative way. This enables the relational verification of program schemas, which we exploit to prove compiler optimizations that cannot be handled by other tools. Our method requires an extension of standard LCTRSs with axiomatized symbols, which generate new research questions. We also present a prototype implementation that proves the practical feasibility of our approach.