Scholar iON
Academic Synthesis
The collection of papers addresses diverse computational and algorithmic challenges within the context of instruction execution, memory management, logic programming, and constraint optimization. Bergstra and Middelburg explore the execution behaviors of instruction sequences using the Algebra of Communicating Processes (ACP), highlighting the capacity of ACP to model finite-state behaviors in remote instruction processing. Abdullaβs work introduces the Virtual Garbage Collector (VGC), focusing on enhancing memory predictability in Python runtimes through a zone-based architecture, suggesting improvements in scalability and deterministic execution. Payet and Mesnard contribute to the field of logic programming by proposing an advanced non-termination criterion for binary constraint logic programs, offering a generalized framework for non-termination detection. Lastly, Bracchi et al. present visualization tools in ILOG OPL Studio that enhance debugging and performance tuning by combining propagation information with search tree analytics, introducing innovative visualization methods like the "Christmas Tree" view. Collectively, these studies advance the understanding of computational behaviors and optimization techniques, offering novel frameworks and tools for improving execution performance and reliability.
We study several aspects of the behaviours produced by instruction sequences under execution in the setting of the algebraic theory of processes known as ACP. We use ACP to describe the behaviours produced by instruction sequences under execution and to describe two protocols implementing these behaviours in the case where the processing of instructions takes place remotely. We also show that all finite-state behaviours considered in ACP can be produced by instruction sequences under execution.
The Virtual Garbage Collector (VGC) proposes a zone-based memory management architecture aimed at improving execution predictability and memory behavior in Python runtimes. The design explores a dual-layer model consisting of an Active VGC, responsible for managing runtime object lifecycles, and a Passive VGC, intended as a compile-time optimization layer for static allocation planning. Rather than relying on traditional heap traversal or generational heuristics, VGC introduces memory zoning and checkpoint-based state evaluation to reduce allocation churn and constrain garbage collection scope. Execution partitioning is experimentally evaluated to isolate workloads and localize memory pressure, enabling more deterministic behavior under loop-intensive, recursive, and compute-heavy workloads. This work presents the architectural principles, execution model, and experimental observations of VGC within a partition-aware runtime context. While the full realization of the dual-layer design is an ongoing effort, the results indicate that zone-based allocation and partitioned execution provide a viable foundation for improving scalability and memory predictability in Python-oriented systems.
On one hand, termination analysis of logic programs is now a fairly established research topic within the logic programming community. On the other hand, non-termination analysis seems to remain a much less attractive subject. If we divide this line of research into two kinds of approaches: dynamic versus static analysis, this paper belongs to the latter. It proposes a criterion for detecting non-terminating atomic queries with respect to binary CLP clauses, which strictly generalizes our previous works on this subject. We give a generic operational definition and a logical form of this criterion. Then we show that the logical form is correct and complete with respect to the operational definition.
In this paper we give an overview of the current state of the graphical features provided by ILOG OPL Studio for debugging and performance tuning of OPL programs or external ILOG Solver based applications. This paper focuses on combining propagation and search information using the Search Tree view and the Propagation Spy. A new synthetic view is presented: the Christmas Tree, which combines the Search Tree view with statistics on the efficiency of the domain reduction and on the number of the propagation events triggered.
The relationship between abstract interpretation and partial deduction has received considerable attention and (partial) integrations have been proposed starting from both the partial deduction and abstract interpretation perspectives. In this work we present what we argue is the first fully described generic algorithm for efficient and precise integration of abstract interpretation and partial deduction. Taking as starting point state-of-the-art algorithms for context-sensitive, polyvariant abstract interpretation and (abstract) partial deduction, we present an algorithm which combines the best of both worlds. Key ingredients include the accurate success propagation inherent to abstract interpretation and the powerful program transformations achievable by partial deduction. In our algorithm, the calls which appear in the analysis graph are not analyzed w.r.t. the original definition of the procedure but w.r.t. specialized definitions of these procedures. Such specialized definitions are obtained by applying both unfolding and abstract executability. Our framework is parametric w.r.t. different control strategies and abstract domains. Different combinations of such parameters correspond to existing algorithms for program analysis and specialization. Simultaneously, our approach opens the door to the efficient computation of strictly more precise results than those achievable by each of the individual techniques. The algorithm is now one of the key components of the CiaoPP analysis and specialization system.
The purpose of this paper is to present some functionalities of the HyperPro System. HyperPro is a hypertext tool which allows to develop Constraint Logic Programming (CLP) together with their documentation. The text editing part is not new and is based on the free software Thot. A HyperPro program is a Thot document written in a report style. The tool is designed for CLP but it can be adapted to other programming paradigms as well. Thot offers navigation and editing facilities and synchronized static document views. HyperPro has new functionalities such as document exportations, dynamic views (projections), indexes and version management. Projection is a mechanism for extracting and exporting relevant pieces of code program or of document according to specific criteria. Indexes are useful to find the references and occurrences of a relation in a document, i.e., where its predicate definition is found and where a relation is used in other programs or document versions and, to translate hyper-texts links into paper references. It still lack importation facilities.
Instruction sequence is a key concept in practice, but it has as yet not come prominently into the picture in theoretical circles. This paper concerns instruction sequences, the behaviours produced by them under execution, the interaction between these behaviours and components of the execution environment, and two issues relating to computability theory. Positioning Turing's result regarding the undecidability of the halting problem as a result about programs rather than machines, and taking instruction sequences as programs, we analyse the autosolvability requirement that a program of a certain kind must solve the halting problem for all programs of that kind. We present novel results concerning this autosolvability requirement. The analysis is streamlined by using the notion of a functional unit, which is an abstract state-based model of a machine. In the case where the behaviours exhibited by a component of an execution environment can be viewed as the behaviours of a machine in its different states, the behaviours concerned are completely determined by a functional unit. The above-mentioned analysis involves functional units whose possible states represent the possible contents of the tapes of Turing machines with a particular tape alphabet. We also investigate functional units whose possible states are the natural numbers. This investigation yields a novel computability result, viz. the existence of a universal computable functional unit for natural numbers.
Introduction: Safety criteria in surgical VR training are typically hard-coded and informally summarized. The Virtual Reality (VR) content creation interface, TIPS-author, for the Toolkit for Illustration of Procedures in Surgery (TIPS) allows surgeon-educators (SEs) to create laparoscopic VR-training modules with force feedback. TIPS-author initializes anatomy shape and physical properties selected by the SE accessing a cloud data base of physics-enabled pieces of anatomy. Methods: A new addition to TIPS-author are safety rules that are set by the SE and are automatically monitored during simulation. Errors are recorded as visual snapshots for feedback to the trainee. This paper reports on the implementation and opportunistic evaluation of the snap-shot mechanism as a trainee feedback mechanism. TIPS was field tested at two surgical conferences, one before and one after adding the snapshot feature. Results: While other ratings of TIPS remained unchanged for an overall Likert scale score of 5.24 out of 7 (7 equals very useful), the rating of the statement `The TIPS interface helps learners understand the force necessary to explore the anatomy' improved from 5.04 to 5.35 out of 7 after the snapshot mechanism was added. Conclusions: The ratings indicate the viability of the TIPS open-source2 E-authored surgical training units. Presenting SE-determined procedural missteps via the snapshot mechanism at the end of the training increases acceptance
Improving human health and well-being requires an accurate and effective understanding of an individual's physical and mental state throughout daily life. To support this goal, we utilized smartphones, smartwatches, and sleep sensors to collect data passively and continuously for 24 hours a day, with minimal interference to participants' usual behavior, enabling us to gather quantitative data on daily behaviors and sleep activities across multiple days. Additionally, we gathered subjective self-reports of participants' fatigue, stress, and sleep quality through surveys conducted immediately before and after sleep. This comprehensive lifelog dataset is expected to provide a foundational resource for exploring meaningful insights into human daily life and lifestyle patterns, and a portion of the data has been anonymized and made publicly available for further research. In this paper, we introduce the ETRI Lifelog Dataset 2024, detailing its structure and presenting potential applications, such as using machine learning models to predict sleep quality and stress.
Recent developments in hybrid biological-technological systems (hybrid bionic systems) has made clear the need for evaluating ergonomic fit in such systems, especially as users first become adjusted to using such systems. This training is accompanied by physiological adaptation, and can be thought of computationally as a relative degree of matching between prosthetic devices, physiology, and behavior. Achieving performance augmentation involves two features of performance: a specific form of learning, memory, and mechanotransduction called sensorimotor learning, and physiological adaptation to novel physical information imposed by the augmented environment of hybrid bionic systems. A method borrowed from environmental medicine involving perturbing the environment for a range of internal physiological conditions was used to induce sensorimotor learning and memory associated physiological changes. In addition, features of the adult phenotype were considered as a mitigator of learning-related adaptations. Using a series of statistical tests and techniques, the results demonstrate than three forms of regulation are at work related to morphological, neural, and muscular control. A discussion of the conceptual relationship between homeostasis and adaptation will then be discussed in addition to potential applications to performance augmentation strategies.