Constraint Checking Research Articles

Using finite transducers for describing and synthesising structural time-series constraints

We describe a large family of constraints for structural time series by means of function composition. These constraints are on aggregations of features of patterns that occur in a time series, such as the number of its peaks, or the range of its steepest ascent. The patterns and features are usually linked to physical properties of the time series generator, which are important to capture in a constraint model of the system, i.e. a conjunction of constraints that produces similar time series. We formalise the patterns using finite transducers, whose output alphabet corresponds to semantic values that precisely describe the steps for identifying the occurrences of a pattern. Based on that description, we automatically synthesise automata with accumulators, as well as constraint checkers. The description scheme not only unifies the structure of the existing 30 time-series constraints in the Global Constraint Catalogue, but also leads to over 600 new constraints, with more than 100,000 lines of synthesised code.

PTL: A model transformation language based on logic programming

In this paper we present a model transformation language based on logic programming. The language, called PTL (Prolog based Transformation Language), can be considered as a hybrid language in which ATL (Atlas Transformation Language)-style rules are combined with logic rules for defining transformations. ATL-style rules are used to define mappings from source models to target models while logic rules are used as helpers. The implementation of PTL is based on the encoding of the ATL-style rules by Prolog rules. Thus, PTL makes use of Prolog as a transformation engine. We have provided a declarative semantics to PTL and proved the semantics equivalent to the encoded program. We have studied an encoding of OCL (Object Constraint Language) with Prolog goals in order to map ATL to PTL. Thus a subset of PTL can be considered equivalent to a subset of ATL. The proposed language can be also used for model validation, that is, for checking constraints on models and transformations. We have equipped our language with debugging and tracing capabilities which help developers to detect programming errors in PTL rules. Additionally, we have developed an Eclipse plugin for editing PTL programs, as well as for debugging, tracing and validation. Finally, we have evaluated the language with several transformation examples as well as tested the performance with large models.

Ontology-based knowledge modeling for automated construction safety checking

Safety management is the most important part of the construction management on building engineering which has dynamic work environment and complicated construction procedure. Safety checking which identifies hazards before they occur is a core process of safety management on construction sites. However, the traditional construction safety checking which is operated by the experienced manager is manual and time-consuming. In order to integrate new technology into the construction safety checking system, a meta model for construction safety checking i.e. CSCOntology (Construction Safety Checking Ontology) has been developed in this paper. This model is formalized using an ontology language, OWL for encoding knowledge over the Web. Safety checking constraints which can extract from construction safety regulation provisions are represented with a rule language, SWRL. Then the construction safety checking processes are implemented in the JESS, a rule engine for the Java platform by transforming OWL knowledge into JESS facts, and SWRL constraints into JESS rules. A real-world example has been demonstrated in Protégé 3.4 beta to show the proposed safety checking process, according to the regulation examples taken from “29 CFR 1926 OSHA Construction Industry Regulations”.

Weakening Cardinality Constraints Creates Harder Satisfiability Benchmarks

For some time, the satisfiability formulae that have been the most difficult to solve for their size have been crafted to be unsatisfiable by the use of cardinality constraints. Recent solvers have introduced explicit checking of such constraints, rendering previously difficult formulae trivial to solve. A family of unsatisfiable formulae is described that is derived from the sgen4 family but cannot be solved using cardinality constraints detection and reasoning alone. These formulae were found to be the most difficult during the SAT2014 competition by a significant margin and include the shortest unsolved benchmark in the competition, sgen6-1200-5-1.cnf.

KnowLife: a versatile approach for constructing a large knowledge graph for biomedical sciences.

BackgroundBiomedical knowledge bases (KB’s) have become important assets in life sciences. Prior work on KB construction has three major limitations. First, most biomedical KBs are manually built and curated, and cannot keep up with the rate at which new findings are published. Second, for automatic information extraction (IE), the text genre of choice has been scientific publications, neglecting sources like health portals and online communities. Third, most prior work on IE has focused on the molecular level or chemogenomics only, like protein-protein interactions or gene-drug relationships, or solely address highly specific topics such as drug effects.ResultsWe address these three limitations by a versatile and scalable approach to automatic KB construction. Using a small number of seed facts for distant supervision of pattern-based extraction, we harvest a huge number of facts in an automated manner without requiring any explicit training.We extend previous techniques for pattern-based IE with confidence statistics, and we combine this recall-oriented stage with logical reasoning for consistency constraint checking to achieve high precision. To our knowledge, this is the first method that uses consistency checking for biomedical relations. Our approach can be easily extended to incorporate additional relations and constraints.We ran extensive experiments not only for scientific publications, but also for encyclopedic health portals and online communities, creating different KB’s based on different configurations. We assess the size and quality of each KB, in terms of number of facts and precision. The best configured KB, KnowLife, contains more than 500,000 facts at a precision of 93% for 13 relations covering genes, organs, diseases, symptoms, treatments, as well as environmental and lifestyle risk factors.ConclusionKnowLife is a large knowledge base for health and life sciences, automatically constructed from different Web sources. As a unique feature, KnowLife is harvested from different text genres such as scientific publications, health portals, and online communities. Thus, it has the potential to serve as one-stop portal for a wide range of relations and use cases. To showcase the breadth and usefulness, we make the KnowLife KB accessible through the health portal (http://knowlife.mpi-inf.mpg.de).Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-015-0549-5) contains supplementary material, which is available to authorized users.

CHECKING OF CONCEPTUAL MODELS WITH INTEGRITY CONSTRAINTS

Due to the raising level of abstraction in information systems development many activities of this process are migrating to its early phases. The same is true for testing – modern CASE tools are undertaking validation of software models. In this paper the methodology for checking of conceptual models is proposed as the step-wise pro-cess during which model elements including integrity constraints are progressively checked for their adequacy to values of objects, their relationships and constraints of the corresponding problem domain. The checking process is associated with the particular methodology for development of ordered and precise conceptual models (OPCM), which brings improvements to their quality: conformity to normal forms and ontological foundations, and to the observed reality. The rules for checking of integrity constraints are proposed on the base of taxonomy created in the result of analysis of the most promising methods for conceptual modelling.

Development of a Low-Cost Parallel Kinematic Machine for Multidirectional Additive Manufacturing

Most additive manufacturing (AM) processes are layer-based with three linear motions in the X, Y, and Z axes. However, there are drawbacks associated with such limited motions, e.g., nonconformal material properties, stair-stepping effect, and limitations on building-around-inserts. Such drawbacks will limit AM to be used in more general applications. To enable 6-axis motions between a tool and a work piece, we investigated a Stewart mechanism and the feasibility of developing a low-cost 3D printer for the multidirectional fused deposition modeling (FDM) process. The technical challenges in developing such an AM system are discussed including the hardware design, motion planning and modeling, platform constraint checking, tool motion simulation, and platform calibration. Several test cases are performed to illustrate the capability of the developed multidirectional AM system. A discussion of future development on multidirectional AM systems is also given.

Real-Time Symbolic Dynamic Programming

Recent advances in Symbolic Dynamic Programming (SDP) combined withthe extended algebraic decision diagram (XADD) have provided exactsolutions for expressive subclasses of finite-horizon Hybrid MarkovDecision Processes (HMDPs) with mixed continuous and discrete stateand action parameters. Unfortunately, SDP suffers from two majordrawbacks: (1) it solves for all states and can be intractable formany problems that inherently have large optimal XADD value functionrepresentations; and (2) it cannot maintain compact (pruned) XADDrepresentations for domains with nonlinear dynamics and reward due tothe need for nonlinear constraint checking. In this work, wesimultaneously address both of these problems by introducing real-timeSDP (RTSDP). RTSDP addresses (1) by focusing the solution and valuerepresentation only on regions reachable from a set of initial statesand RTSDP addresses (2) by using visited states as witnesses ofreachable regions to assist in pruning irrelevant or unreachable(nonlinear) regions of the value function. To this end, RTSDP enjoysprovable convergence over the set of initial states and substantialspace and time savings over SDP as we demonstrate in a variety of hybrid domains ranging from inventory to reservoir to traffic control.

Using Description Logics for RDF Constraint Checking and Closed-World Recognition

RDF and Description Logics work in an open-world setting where absence of information is not information about absence. Nevertheless, Description Logic axioms can be interpreted in a closed-world setting and in this setting they can be used for both constraint checking and closed-world recognition against information sources. When the information sources are expressed in well-behaved RDF or RDFS (i.e., RDF graphs interpreted in the RDF or RDFS semantics) this constraint checking and closed-world recognition is simple to describe. Further this constraint checking can be implemented as SPARQL querying and thus effectively performed.

Использование языка программирования Python для описания ограничений на архитектурные модели

The paper presents an approach to specify constraints on AADL models in Python-based language and a toolset allowing to verify that constraints. The goal of the approach is to enable reusing of existing rich facilities of Python language, tools, and libraries as well as to reduce learning curve of engineers. Constraints must be placed into component annexes. These constraints must be written in Python programming language as functions with one argument (an object to be checked), Boolean result, and special decorator. A plugin for a modeling environment generates a program in Python from the model components declarations. While it is executing this program creates an object with the model instance and checks the object by functions from annexes. This approach is implemented in MASIW Framework that allows checking constraints on model instance. The implementation is made upon PyDev, a well-known Eclipse-plugin for Python developing in Eclipse and reuses integration of Eclipse with Python from PyDev.

Unified matheuristic for solving rich vehicle routing problems

The purpose of this thesis is to develop a solution framework for Rich Vehicle Routing Problems (RVRPs). We first provide a comprehensive survey of the RVRP literature as well as a taxonomy. Selected papers addressing various variants are classified according to the proposed taxonomy. A cluster analysis based on two discriminating criteria is performed and leads to define RVRPs. In this thesis we are interested in solving a multi-depot multi-compartment multi-commodity vehicle routing problem with time windows (MDMCMCm-VRPTW). We propose a unified column generation heuristic cooperating with a variable neighborhood search (VNS) matheuristic. The VNS combines several removal and insertion routing heuristics as well as computationally efficient constraint checking. Two loading neighborhoods based on the solution of mathematical programs are proposed to intensify the search. On a set of 191 instances of less complex routing problems, the unified matheuristic turns to be competitive. A sensitivity analysis, performed on more complex generated instances reveals the importance of some algorithmic features and of loading neighborhoods for reaching high quality solutions. The VNS based matheuristic is embedded in a column generation heuristic to solve the MDMCMCm-VRPTW. We propose an exact post-processing method to optimize the assignment ofcustomers to vehicle routes. Last, we introduce, model and solve to optimality a RVRP arising in the olive oil collection process in Tunisia. We propose an exact branch-and-cut algorithm to solve the problem. We evaluate the performance of the algorithm on real data sets under different transportation scenarios

Formal Specification of the Assurance Point Web Service Composition Model

This paper presents a formal specification of the Assurance Point (AP) web service composition model. The AP model provides a flexible way of checking constraints and responding to execution errors in service composition. An AP is a combined logical and physical checkpoint, providing an execution milestone that stores critical data and interacts with integration rules (IRs) to alter program flow and to invoke different forms of recovery depending on the execution status. In this paper, the execution and recovery semantics of assurance points have been fully defined in the context of if-else, parallel, and loop control structures. The activities and complex control structures of the AP model have been formalized and tested in the Yet Another Workflow Language (YAWL) engine. By doing so, the correctness of the execution and recovery semantics in the AP model has been verified, demonstrating that YAWL nets of the AP model satisfy the soundness property. Different from existing web service composition models, the AP model presented by this research provides multiple levels of protection against service execution failure with a combination of forward and backward recovery techniques.

Acquisition of object clitics in child Polish: Evidence for three developmental stages

Cross linguistic variation in L1 clitic acquisition is limited and well-governed, and has been attributed to an underlying syntactic mechanism, such as the Unique Checking Constraint (UCC) in connection with clitic-past participle agreement (Wexler et al., 2003), or a pragmatic constraint, such as Failed Referentiality (Schaeffer, 2000). The present study seeks to validate the claims following from the above theories by looking at the clitic acquisition facts in child Polish in two experiments: clitic production and clitic comprehension. The paper argues that claims following from the two acquisition theories are not supported by Polish L1 data due to an initially high clitic omission rate (60%) and the evidence of early clitic comprehension which precedes clitic production. By comparing clitic production and clitic comprehension results, three developmental stages are identified. A maturational account is adopted attributing non-adult-like structures in child grammar to a discourse-linking mechanism (Borer and Rohrbacher, 2002).

Transmission expansion planning using AC‐based differential evolution algorithm

The rapid growth of the transmission networks has brought more uncertainties and new requirements in the transmission expansion planning (TEP) to the planners. The existing methods of solving TEP problem have a drawback since the DC load flow and the relaxed load flow models have been utilized to solve TEP problem. In this work, the TEP problem is solved based on mixed integer nonlinear non-convex programming model. A meta-heuristic algorithm by the means of differential evolution algorithm (DEA) is employed as an optimisation tool. An AC load flow model is used in solving the TEP problem, where accurate and realistic results can be obtained. Furthermore, the work considers the constraints checking and system violation such as real and power generation limits, possible number of lines added and bus voltage limits. The proposed technique is tested on Garver's 6 bus system and IEEE 24 bus system and has shown high capability in considering the active and reactive power in the same manner and solving the TEP problem. The method produced improved results for the test systems. In terms of minimising the cost and the solution quality, the proposed method obtained good and challenging results comparing to the previous works.

The Design and Implementation of Optimal Scheduling in Hydro-Thermal-Wind System

This paper mainly put forwards the design and implementation of hydropower, thermal power, and wind power joint optimal scheduling system, introduces the framework and functional module of JAVA enterprise application technology, and focuses on the key technologies of the system. The system is based on provincial scheduling automation platform. It takes decision-making as the target, realizes wind power probability prediction, conventional power generation planning, hydropower, thermal power, and wind power joint scheduling, constraint checking, impact assessment and other functions, and helps the operators to make scientific and reasonable power generation plans, achieve intelligent scheduling, and enhance system operation level.

The Advantages of Using CHECK Constraints in The Academic Database Tables

Database plays important role on both web-based or desktop-based information system. Nowadays web-based information systems dominate information system application. Relational database systems such as Oracle, MySQL, MS SQL Server or PostgreSQL are familiarly used as data base management system. In Indonesia almost all academic information systems at higher education institutions are web-based application with RDBMS as database software. Some researches show the lack of data input validation that makes problem on data security and data quality. Input sanity is a problem that needs a serious attention. Data validation can be done by making a constraint in the database or application level. The fact is that validation in database level is less done by programmers. This research will perform the analysis of advantages or disadvantages from CHECK constraint on database table of academic information system.

Virtual prototyping through multisoftware integration for energy harvester design

A strong integration between different design tools is desirable to improve the work of engineers, reducing the number of errors and speeding up the design process. In this article, the authors present a strong integration between three-dimensional computer-aided design models and multidomain simulation applied to the design of a magnetomechanical energy harvester. A MATLAB framework controls a block-oriented Simulink model, drives the Finite Element Method Magnetic simulation and manages the updating of the SolidWorks computer-aided design models of the device. The parameters involved in the different simulations and in the computer-aided design models are stored in a unique data file. Moreover, constructive drawings are automatically updated and are immediately suitable for tolerance and design constraint checks and also for the effective prototyping of the device. Constructed prototypes are immediately suitable to validate the performance predicted by the model.

Public facility location using dispersion, population, and equity criteria

From a practical perspective, the paper demonstrates that the appropriate use of dispersion, population, and equity criteria can lead to fairly good solutions with respect to the p-median objective. The only stipulation is that the decision maker verifies (through simple constraint checks) that the chosen locations meet the dispersion, population, and equity criteria. An empirical investigation is conducted to obtain appropriate values for these parameters. From a location science perspective, a new location model that accounts for equity and efficiency simultaneously is studied and analyzed. Specifically, the p-maxian problem with side constraints on dispersion, population, and equity is developed, its NP-completeness established, and valid inequalities and bounds derived. Computational tests show encouraging results.

Colored Petri Net model with automatic parallelization on real-time multicore architectures

This paper proposes a novel Colored Petri Net (CPN) based dynamic scheduling scheme, which aims at scheduling real-time tasks on multiprocessor system-on-chip (MPSoC) platforms. Our CPN based scheme addresses two key issues on task scheduling problems, dependence detecting and task dispatching. We model inter-task dependences using CPN, including true-dependences, output-dependences, anti-dependences and structural dependences. The dependences can be detected automatically during model execution. Additionally, the proposed model takes the checking of real-time constraints into consideration. We evaluated the scheduling scheme on the state-of-art FPGA based multiprocessor hardware system and modeled the system behavior using CPN tools. Simulations and state space analyses are conducted on the model. Experimental results demonstrate that our scheme can achieve 98.9% of the ideal speedup on a real FPGA based hardware prototype.

A Temporal Motif Mining Approach to Unsupervised Energy Disaggregation: Applications to Residential and Commercial Buildings

Non-intrusive appliance load monitoring has emerged as an attractive approach to study energy consumption patterns without instrumenting every device in a building. The ensuing computational problem is to disaggregate total energy usage into usage by specific devices, to gain insight into consumption patterns. We exploit the temporal ordering implicit in on/off events of devices to uncover motifs (episodes) corresponding to the operation of individual devices. Extracted motifs are then subjected to a sequence of constraint checks to ensure that the resulting episodes are interpretable. Our results reveal that motif mining is adept at distinguishing devices with multiple power levels and at disentangling the combinatorial operation of devices. With suitably configured processing steps, we demonstrate the applicability of our method to both residential and commercial buildings.