On Formal Methods for Large-Scale Product Configuration

<p>In product development companies mass customization is widely used to achieve better customer satisfaction while keeping costs down. To efficiently implement mass customization, product platforms are often used. A product platform allows building a wide range of products from a set of predefined components. The process of matching these components to customers' needs is called product configuration. Not all components can be combined with each other due to restrictions of various kinds, for example, geometrical, marketing and legal reasons. Product design engineers develop configuration constraints to describe such restrictions. The number of constraints and the complexity of the relations between them are immense for complex product like a vehicle. Thus, it is both error-prone and time consuming to analyze, author and verify the constraints manually. Software tools based on formal methods can help engineers to avoid making errors when working with configuration constraints, thus design a correct product faster.</p> <p>This thesis introduces a number of formal methods to help engineers maintain, verify and analyze product configuration constraints. These methods provide automatic verification of constraints and computational support for analyzing and refactoring constraints. The methods also allow verifying the correctness of one specific type of constraints, item usage rules, for sets of mutually-exclusive required items, and automatic verification of equivalence of different formulations of the constraints. The thesis also introduces three methods for efficient enumeration of valid partial configurations, with benchmarking of the methods on an industrial dataset.</p> <p>Handling large-scale industrial product configuration problems demands high efficiency from the software methods. This thesis investigates a number of search-based and knowledge-compilation-based methods for working with large product configuration instances, including Boolean satisfiability solvers, binary decision diagrams and decomposable negation normal form. This thesis also proposes a novel method based on supervisory control theory for efficient reasoning about product configuration data. The methods were implemented in a tool, to investigate the applicability of the methods for handling large product configuration problems. It was found that search-based Boolean satisfiability solvers with incremental capabilities are well suited for industrial configuration problems.</p> <p>The methods proposed in this thesis exhibit good performance on practical configuration problems, and have a potential to be implemented in industry to support product design engineers in creating and maintaining configuration constraints, and speed up the development of product platforms and new products.</p

Topical Issues of Administration of Migration Processes on Space of the CSTO in Modern Conditions

The purpose given works is improvement of legal administration of migration processes on space of the CSTO in modern conditions. On the basis of scientific methods of knowledge, the author analyzes the current state of the studied perspective, topical issues of legal regulation of migration processes as in global world scale, and applicable the territory which is under jurisdiction of the CSTO are studied. The author the reasons reveal and conditions of emergence of undesirable migrations when under the guise of refugees fighters get on the adjacent territory for commission of acts of terrorism come to light. Summarizing the author it is advisable to initiate consideration of a question of legislative restriction of undesirable migrations not only in theRussian Federation, but also in the CSTO State Parties as borders “are absolutely transparent” here

SAT-Solving in Practice, with a Tutorial Example from Supervisory Control

Satisfiability solving, the problem of deciding whether the variables of a propositional formula can be assigned in such a way that the formula evaluates to true, is one of the classic problems in computer science. It is of theoretical interest because it is the canonical NP-complete problem. It is of practical interest because modern SAT-solvers can be used to solve many important and practical problems. In this tutorial paper, we show briefly how such SAT-solvers are implemented, and point to some typical applications of them. Our aim is to provide sufficient information (much of it through the reference list) to kick-start researchers from new fields wishing to apply SAT-solvers to their problems. Supervisory control theory originated within the control community and is a framework for reasoning about a plant to be controlled and a specification that the closed-loop system must fulfil. This paper aims to bridge the gap between the computer science community and the control community by illustrating how SAT-based techniques can be used to solve some supervisory control related problems

Lagrange structure and quantization

A path-integral quantization method is proposed for dynamical systems whose classical equations of motion do \textit{not} necessarily follow from the action principle. The key new notion behind this quantization scheme is the Lagrange structure which is more general than the Lagrangian formalism in the same sense as Poisson geometry is more general than the symplectic one. The Lagrange structure is shown to admit a natural BRST description which is used to construct an AKSZ-type topological sigma-model. The dynamics of this sigma-model in $d+1$ dimensions, being localized on the boundary, are proved to be equivalent to the original theory in $d$ dimensions. As the topological sigma-model has a well defined action, it is path-integral quantized in the usual way that results in quantization of the original (not necessarily Lagrangian) theory. When the original equations of motion come from the action principle, the standard BV path-integral is explicitly deduced from the proposed quantization scheme. The general quantization scheme is exemplified by several models including the ones whose classical dynamics are not variational.Comment: Minor corrections, format changed, 40 page

Free-floating car-sharing electrification and mode displacement: Travel time and usage patterns from 12 cities in Europe and the United States

Free-floating car-sharing (FFCS) allows users to book a vehicle through their phone, use it and return it anywhere within a designated area in the city. FFCS has the potential to contribute to a transition to low-carbon mobility if the vehicles are electric, and if the usage does not displace active travel or public transport use. The aim of this paper is to study what travel time and usage patterns of the vehicles among the early adopters of the service reveal about these two issues. We base our analysis on a dataset containing rentals from 2014 to 2017, for 12 cities in Europe and the United States. For seven of these cities, we have collected travel times for equivalent trips with walking, biking, public transport and private car. FFCS services are mainly used for shorter trips with a median rental time of 27 min and actual driving time closer to 15 min. When comparing FFCS with other transport modes, we find that rental times are generally shorter than the equivalent walking time but longer than cycling. For public transport, the picture is mixed: for some trips there is no major time gain from taking FFCS, for others it could be up to 30 min. For electric FFCS vehicles rental time is shorter and the number of rentals per car and day are slightly fewer compared to conventional vehicles. Still, evidence from cities with an only electric fleet show that these services can be electrified and reach high levels of utilization

DockStream: a docking wrapper to enhance de novo molecular design

Recently, we have released the de novo design platform REINVENT in version 2.0. This improved and extended iteration supports far more features and scoring function components, which allows bespoke and tailor-made protocols to maximize impact in small molecule drug discovery projects. A major obstacle of generative models is producing active compounds, in which predictive (QSAR) models have been applied to enrich target activity. However, QSAR models are inherently limited by their applicability domains. To overcome these limitations, we introduce a structure-based scoring component for REINVENT. DockStream is a flexible, stand-alone molecular docking wrapper that provides access to a collection of ligand embedders and docking backends. Using the benchmarking and analysis workflow provided in DockStream, execution and subsequent analysis of a variety of docking configurations can be automated. Docking algorithms vary greatly in performance depending on the target and the benchmarking and analysis workflow provides a streamlined solution to identifying productive docking configurations. We show that an informative docking configuration can inform the REINVENT agent to optimize towards improving docking scores using public data. With docking activated, REINVENT is able to retain key interactions in the binding site, discard molecules which do not fit the binding cavity, harness unused (sub-)pockets, and improve overall performance in the scaffold-hopping scenario. The code is freely available at https://github.com/MolecularAI/DockStream

Learning to Solve Voxel Building Embodied Tasks from Pixels and Natural Language Instructions

The adoption of pre-trained language models to generate action plans for embodied agents is a promising research strategy. However, execution of instructions in real or simulated environments requires verification of the feasibility of actions as well as their relevance to the completion of a goal. We propose a new method that combines a language model and reinforcement learning for the task of building objects in a Minecraft-like environment according to the natural language instructions. Our method first generates a set of consistently achievable sub-goals from the instructions and then completes associated sub-tasks with a pre-trained RL policy. The proposed method formed the RL baseline at the IGLU 2022 competition.Comment: 6 pages, 3 figure

Using Formal Methods for Product and Production Development -- Industrial Applications for Boolean Satisfiability Solvers

Highly customized products and frequent changes in the production systems pose high demands on engineers. The amount of data and the complexity of the relations within the data are high. Thus, it is both error-prone and time consuming to analyze the data without software support. Software tools based on formal methods can help engineers analyze the data in order to avoid errors and deliver correct results faster. In this thesis formal methods have been applied both to solve product configuration problems and to support the development of control functions for production systems.Software-based configurators might help engineers to create, verify, and maintain the large sets of the configuration constraints that govern which of the customizable parts and features of the product are combinable with each other. In this thesis it is investigated how configurators can be used during product development. An important problem for configurators used within product development is to generate sets of allowed partial configurations. The performance of different algorithms based on general-purpose constraint solvers, Boolean satisfiability solvers (SAT-solvers), and Binary Decision Diagrams (BDDs) has been evaluated on industrial data from the automotive industry. The results show that the tools based on BDDs have problems handling large instances, while SAT-solvers and general-purpose constraint solvers are both able to solve large problems. A SAT-solver based configurator, implemented as a part of this research, can efficiently compute partial configurations for industrial-sized problems.In a production system process operations are used to describe sub-tasks and relations between them. These process operations must be coordinated in order to satisfy given specifications. Supervisory Control Theory (SCT) can be used to verify the coordination of operations and synthesize correct-by-construction control functions. This thesis presents a method for verification and synthesis of SCT-based control functions using SAT-solvers. A method for verification of SCT properties for systems modeled as Extended Finite Automata is also presented.Tools for both product configuration and SCT verification and synthesis have been implemented as part of this research. They can be used to help engineers ensure correctness of products and production systems of high complexity

On Formal Methods for Large-Scale Product Configuration

In product development companies mass customization is widely used to achieve better customer satisfaction while keeping costs down. To efficiently implement mass customization, product platforms are often used. A product platform allows building a wide range of products from a set of predefined components. The process of matching these components to customers\u27 needs is called product configuration. Not all components can be combined with each other due to restrictions of various kinds, for example, geometrical, marketing and legal reasons. Product design engineers develop configuration constraints to describe such restrictions. The number of constraints and the complexity of the relations between them are immense for complex product like a vehicle. Thus, it is both error-prone and time consuming to analyze, author and verify the constraints manually. Software tools based on formal methods can help engineers to avoid making errors when working with configuration constraints, thus design a correct product faster.This thesis introduces a number of formal methods to help engineers maintain, verify and analyze product configuration constraints. These methods provide automatic verification of constraints and computational support for analyzing and refactoring constraints. The methods also allow verifying the correctness of one specific type of constraints, item usage rules, for sets of mutually-exclusive required items, and automatic verification of equivalence of different formulations of the constraints. The thesis also introduces three methods for efficient enumeration of valid partial configurations, with benchmarking of the methods on an industrial dataset.Handling large-scale industrial product configuration problems demands high efficiency from the software methods. This thesis investigates a number of search-based and knowledge-compilation-based methods for working with large product configuration instances, including Boolean satisfiability solvers, binary decision diagrams and decomposable negation normal form. This thesis also proposes a novel method based on supervisory control theory for efficient reasoning about product configuration data. The methods were implemented in a tool, to investigate the applicability of the methods for handling large product configuration problems. It was found that search-based Boolean satisfiability solvers with incremental capabilities are well suited for industrial configuration problems.The methods proposed in this thesis exhibit good performance on practical configuration problems, and have a potential to be implemented in industry to support product design engineers in creating and maintaining configuration constraints, and speed up the development of product platforms and new products

Using Formal Methods for Product and Production Development -- Industrial Applications for Boolean Satisfiability Solvers

Highly customized products and frequent changes in the production systems pose high demands on engineers. The amount of data and the complexity of the relations within the data are high. Thus, it is both error-prone and time consuming to analyze the data without software support. Software tools based on formal methods can help engineers analyze the data in order to avoid errors and deliver correct results faster. In this thesis formal methods have been applied both to solve product configuration problems and to support the development of control functions for production systems.Software-based configurators might help engineers to create, verify, and maintain the large sets of the configuration constraints that govern which of the customizable parts and features of the product are combinable with each other. In this thesis it is investigated how configurators can be used during product development. An important problem for configurators used within product development is to generate sets of allowed partial configurations. The performance of different algorithms based on general-purpose constraint solvers, Boolean satisfiability solvers (SAT-solvers), and Binary Decision Diagrams (BDDs) has been evaluated on industrial data from the automotive industry. The results show that the tools based on BDDs have problems handling large instances, while SAT-solvers and general-purpose constraint solvers are both able to solve large problems. A SAT-solver based configurator, implemented as a part of this research, can efficiently compute partial configurations for industrial-sized problems.In a production system process operations are used to describe sub-tasks and relations between them. These process operations must be coordinated in order to satisfy given specifications. Supervisory Control Theory (SCT) can be used to verify the coordination of operations and synthesize correct-by-construction control functions. This thesis presents a method for verification and synthesis of SCT-based control functions using SAT-solvers. A method for verification of SCT properties for systems modeled as Extended Finite Automata is also presented.Tools for both product configuration and SCT verification and synthesis have been implemented as part of this research. They can be used to help engineers ensure correctness of products and production systems of high complexity