Efficient analysis of pattern-based constraint specifications

Precision and consistency are important prerequisites for class models to conform to their intended domain semantics. Precision can be achieved by augmenting models with design constraints and consistency can be achieved by avoiding contradictory constraints. However, there are different views of what constitutes a contradiction for design constraints. Moreover, state-of-the-art analysis approaches for proving constrained models consistent either scale poorly or require the use of interactive theorem proving. In this paper, we present a heuristic approach for efficiently analyzing constraint specifications built from constraint patterns. This analysis is based on precise notions of consistency for constrained class models and exploits the semantic properties of constraint patterns, thereby enabling syntax-based consistency checking in polynomial-time. We introduce a consistency checker implementing these ideas and we report on case studies in applying our approach to analyze industrial-scale models. These studies show that pattern-based constraint development supports the creation of concise specifications and provides immediate feedback on model consistency.     

State-space analysis and identification for a class of hysteretic systems

In this paper we present results on the twin subjects of system analysis and system identification for a class of state-space realizable dynamic systems under the influence of hysteresis. The class of systems in question consists of models in the form of a linear time-invariant dynamic system in series with a differential model of hysteresis. It will be demonstrated that under fairly light constraints on the differential model of hysteresis, it is possible to design a series of experiments leading towards the identification of the full state-space realization. The approach is tested successfully on a high-precision mechanical translation system affected by hysteresis.     

Designing secure databases

Security is an important issue that must be considered as a fundamental requirement in information systems development, and particularly in database design. Therefore security, as a further quality property of software, must be tackled at all stages of the development. The most extended secure database model is the multilevel model, which permits the classification of information according to its confidentiality, and considers mandatory access control. Nevertheless, the problem is that no database design methodologies that consider security (and therefore secure database models) across the entire life cycle, particularly at the earliest stages currently exist. Therefore it is not possible to design secure databases appropriately. Our aim is to solve this problem by proposing a methodology for the design of secure databases. In addition to this methodology, we have defined some models that allow us to include security information in the database model, and a constraint language to define security constraints. As a result, we can specify a fine-grained classification of the information, defining with a high degree of accuracy which properties each user has to own in order to be able to access each piece of information. The methodology consists of four stages: requirements gathering; database analysis; multilevel relational logical design; and specific logical design. The first three stages define activities to analyze and design a secure database, thus producing a general secure database model. The last stage is made up of activities that adapt the general secure data model to one of the most popular secure database management systems: Oracle9i Label Security. This methodology has been used in a genuine case by the Data Processing Center of Provincial Government. In order to support the methodology, we have implemented an extension of Rational Rose, including and managing security information and constraints in the first stages of the methodology.     

Matching events and activities by integrating behavioral aspects and label analysis

Nowadays, business processes are increasingly supported by IT services that produce massive amounts of event data during the execution of a process. These event data can be used to analyze the process using process mining techniques to discover the real process, measure conformance to a given process model, or to enhance existing models with performance information. Mapping the produced events to activities of a given process model is essential for conformance checking, annotation and understanding of process mining results. In order to accomplish this mapping with low manual effort, we developed a semi-automatic approach that maps events to activities using insights from behavioral analysis and label analysis. The approach extracts Declare constraints from both the log and the model to build matching constraints to efficiently reduce the number of possible mappings. These mappings are further reduced using techniques from natural language processing, which allow for a matching based on labels and external knowledge sources. The evaluation with synthetic and real-life data demonstrates the effectiveness of the approach and its robustness toward non-conforming execution logs.     

Efficient Deviation Detection Between a Process Model and Event Logs

Business processes described by formal or semi-formal models are realized via information systems. Event logs generated from these systems are probably not consistent with the existing models due to insufficient design of the information system or the system upgrade. By comparing an existing process model with event logs, we can detect inconsistencies called deviations, verify and extend the business process model, and accordingly improve the business process. In this paper, some abnormal activities in business processes are formally defined based on Petri nets. An efficient approach to detect deviations between the process model and event logs is proposed. Then, business process models are revised when abnormal activities exist. A clinical process in a healthcare information system is used as a case study to illustrate our work. Experimental results show the effectiveness and efficiency of the proposed approach.      

SysML-based design chain information modeling for variety management in production reconfiguration

Satisfying diverse customer needs leads to proliferation of product variants. It is imperative to model the coherence of functional, product and process varieties throughout the design chain. Based on a model-based systems engineering approach, this paper applies the Systems Modeling Language (SysML) to model design chain information. To support variety management decisions, the SysML-based information models are further implemented as a variety coding information system. A case study of switchgear enclosure production reconfiguration system demonstrates that SysML-based information modeling excels in conducting requirements, structural, behavioral and constraints analysis and in performing trade-off study. In addition, it maintains semantic coherence along the design chain, keeps traceability across different levels of abstraction, thus improving interoperability among heterogeneous tools.     

Automated analysis of security-design models

We have previously proposed SecureUML, an expressive UML-based language for constructing security-design models, which are models that combine design specifications for distributed systems with specifications of their security policies. Here, we show how to automate the analysis of such models in a semantically precise and meaningful way. In our approach, models are formalized together with scenarios that represent possible run-time instances. Queries about properties of the security policy modeled are expressed as formulas in UML’s Object Constraint Language. The policy may include both declarative aspects, i.e., static access-control information such as the assignment of users and permissions to roles, and programmatic aspects, which depend on dynamic information, namely the satisfaction of authorization constraints in a given scenario. We show how such properties can be evaluated, completely automatically, in the context of the metamodel of the security-design language. We demonstrate, through examples, that this approach can be used to formalize and check non-trivial security properties. The approach has been implemented in the SecureMOVA tool and all of the examples presented have been checked using this tool.     

An approach for the integration of swarm intelligence in MAS: An engineering perspective

For more than 20 years, researchers have designed models in order to describe swarm intelligence and apply the resulting techniques to complex problems. However, there is still a gap between these models and current MAS methodologies. The goal of this paper is to propose a principled and methodological approach for the engineering of systems based upon swarm intelligence. The constraints are, on the one hand, to enable the analysis, design and implementation of such systems; and, on the other hand, to formally analyze and verify properties of resulting systems. The principles of the approach are based, on the one hand, on requirement driven activities that produce goals to be fulfilled by the system of interest and, on the other, hand on an ontological modeling of the problem domain. This ontological modeling conceptualizes the phenomenon one seek to imitate and thus allows it understanding. The produced ontology is refined through the methodology activities down to organizational models.     

元数据存储库系统中违背良格式约束潜在操作的推理

存储库系统的元数据组织方式呈现出分层、多级并且动态变化的复杂结构;存储库系统标准对确保良格式约束规定得并不充分,上述2个原因使得确保基于元对象设施(meta object facility, MOF)建立的元数据存储库系统的状态不违背良格式约束成为一个令人棘手的问题.提出了一种能够自动推断可能违背良格式约束的潜在操作的方法.首先定义了一组比MOF的构造活动更精确和灵活的MOF内部活动并建立了二者之间的对应关系;接着研究了如何推断可能违背约束条件的内部活动;最后通过比对与这些内部活动相对应的构造活动是否在操作规范中出现,研究了如何推断违背约束条件的潜在操作,该方法可以用于约束检测领域.由于可以剔除许多无关的检测,该方法可以有效地提高良格式约束检测的效率.此外该方法对约束设计领域也有一定的参考价值.     

Specifying redundancy tactics as crosscutting concerns using aspect-oriented modeling

Various redundancy tactics can be modeled at the design stage of safety-critical systems thereby providing a set of fault-tolerance guidelines for subsequent development activities. However, existing approaches usually interweave redundancy tactics into the functional models making them complex and cluttered; the maintenance of such models is time-consuming and error-prone. To address this problem, we provide a modeling approach to separate the redundancy tactics from the base functional models using aspect-oriented modeling. More specifically, the conceptual models of the redundancy tactics and their semantic constraints are first defined for deriving the relevant aspects. Subsequently, a UML profile is proposed to specify the tactic aspects followed by mapping these concepts to the corresponding concepts of aspect-oriented modeling based on pre-defined principles. In accordance with our proposed profile, reuse directives are applied to handle the overlap of structural features between redundancy tactics and other kinds of tactic. Based on our tactic aspects and their configured attributes, a weaving algorithm is proposed to associate the tactic aspects with the base functional models. The proposed approach is compared with a traditional tactic modeling approach using two safety-critical systems, revealing that: 1) our approach significantly reduces the number of extra model elements needed in the tactic design stage; 2) our approach can largely avoid the impact of changing of the base functional model as the model evolves.     

A relational view of activities for systems analysis and design

Decision support research has emphasized, traditionally, problem analysis and the use of models in problem solving tasks. Only few models have been promoted for the problem finding and early intelligence stage. A suitable modeling method, we argue, should describe activities in abstract concepts as well as in concrete detail, and should relate interesting activities to organizational goals and constraints. The models would be flexible and expandable enough to be reused in many managerial situations. A case in point is information requirements analysis.We propose a specific relational approach for modeling organizations, in general. Activities and their interactions are represented, at an appropriate level of detail, as diagonal activity matrices. The visual modeling and data collection for further analysis can be started before actual problems have been identified and without preconceived ideas of the eventual activity citing. With the relational activity models, the analysis can focus on problem structuring and information requirements analysis for applications ranging from business planning to transactions processing and operations scheduling. Besides supporting the analysis of organizational problems the relational activity view is also downward-compatible with software design, model management, and prototyping.     

Optimized implementation of synchronous models on industrial LTTA systems

Synchronous models are used to specify embedded systems functions in a clear and unambiguous way and allow verification of properties using formal methods. The implementation of a synchronous specification on a distributed architecture must preserve the model semantics to retain the verification results. Globally synchronized time-triggered architectures offer the simplest implementation path, but can be inefficient or simply unavailable. In past work, we defined a mapping of synchronous models on a general class of distributed asynchronous architectures, for which the only requirement is a lower bound on the rate of activation of tasks. In this paper, we set tighter requirements on task execution rates, and we include a realistic modeling of communication delays, task scheduling delays and schedulability conditions, discussing the timing characteristics of an implementation on a system with a Controller Area Network (CAN). Next, the semantics preservation conditions are formulated as constraints in an architecture optimization problem that defines a feasible task model with respect to timing constraints. An automotive case study shows the applicability of the approach and provides insight on the software design elements that are critical for a feasible implementation.     

Secure activity resource coordination: empirical evidence of enhanced security awareness in designing secure business processes

Systems development methodologies incorporate security requirements as an afterthought in the non-functional requirements of systems. The lack of appropriate access control on information exchange among business activities can leave organizations vulnerable to information assurance threats. The gap between systems development and systems security leads to software development efforts that lack an understanding of security risks. We address the research question: how can we incorporate security as a functional requirement in the analysis and modeling of business processes? This study extends the Semantic approach to Secure Collaborative Inter-Organizational eBusiness Processes in D'Aubeterre et al. (2008). In this study, we develop the secure activity resource coordination (SARC) artifact for a real-world business process. We show how SARC can be used to create business process models characterized by the secure exchange of information within and across organizational boundaries. We present an empirical evaluation of the SARC artifact against the Enriched-Use Case (Siponen et al., 2006) and standard UML-Activity Diagram to demonstrate the utility of the proposed design method.     

Informing the evaluation and design of technology in intentional work environments through a focus on artefacts and implicit theories

Observation and analysis of work and computer systems in context can provide valuable information for the evaluation, design and further development of computer systems; however, there are still questions regarding the analysis and utilization of information from field studies. In particular, from a design viewpoint, it is necessary to be able to move from the extensive observational data that is often collected during a field study to information that is relevant for design. In this paper, we discuss the use of theories and models of human–machine interaction to guide the analysis of information gathered during field studies, and illustrate the application of an artefact-based theory with the results from two different and independently conducted case studies. This approach was valuable in structuring information collected in flexible environments, in which models that rely on the normative procedures found in more causal environments may be less useful. In addition to shaping the interpretation of data from the two studies, the use of an artefact-based theory also proved useful in integrating results across the two field studies, to suggest more domain-independent design criteria.     

Constrained physical design tuning

Existing solutions to the automated physical design problem in database systems attempt to minimize execution costs of input workloads for a given storage constraint. In this work, we argue that this model is not flexible enough to address several real-world situations. To overcome this limitation, we introduce a constraint language that is simple yet powerful enough to express many important scenarios. We build upon a previously proposed transformation-based framework to incorporate constraints into the search space. We then show experimentally that we are able to handle a rich class of constraints and that our proposed technique scales gracefully. Our approach generalizes previous work that assumes simpler optimization models where configuration size is the only fixed constraint. As a consequence, the process of tuning a workload not only becomes more flexible, but also more complex, and getting the best design in the first attempt becomes difficult. We propose a paradigm shift for physical design tuning, in which sessions are highly interactive, allowing DBAs to quickly try different options, identify problems, and obtain physical designs in an agile manner.     

A desktop virtual reality-based interactive modular fixture configuration design system

Modular fixture configuration design is a complicated task requiring strong professional background and practical experience. However, automated or semi-automated computer aided modular fixture systems based on CAD packages still are not well accepted by the manufacturing industry due to the lack of intuitive interaction and immediate feedback compared with traditional models such as paper and physical models. In this paper, a novel Virtual Reality-based system for interactive modular fixture configuration design is presented. We use a multi-view based modular fixture assembly model to assist information representation and management. In addition, the suggested strategy is compatible with the principles of virtual environment and it is easy to reutilize the element model. Based on geometric constraints, we propose a precise 3D manipulation approach to improve intuitive interaction and accurate 3D positioning of fixture components in virtual space. Thus, the modular fixture configuration design task can precisely be performed in virtual space.     

Role of data dictionaries in information resource management

The role of information resource dictionary systems (data dictionary systems) is important in two important phases of information resource management:First, information requirements analysis and specification, which is a complex activity requiring data dictionary support: the end result is the specification of an “Enterprise Model,” which embodies the major activities, processes, information flows, organizational constraints, and concepts. This role is examined in detail after analyzing the existing approaches to requirements analysis and specification.Second, information modeling which uses the information in the Enterprise Model to construct a formal implementation independent database specification: several information models and support tools that may aid in transforming the initial requirements into the final logical database design are examined.The metadata — knowledge about both data and processes — contained in the data dictionary can be used to provide views of data for the specialized tools that make up the database design workbench. The role of data dictionary systems in the integration of tools is discussed.     

Dynamic constraint satisfaction problems over models

In early phases of designing complex systems, models are not sufficiently detailed to serve as an input for automated synthesis tools. Instead, a design space is constituted by multiple models representing different valid design candidates. Design space exploration aims at searching through these candidates defined in the design space to find solutions that satisfy the structural and numeric design constraints and provide a balanced choice with respect to various quality metrics. Design space exploration in an model-driven engineering (MDE) context is frequently tackled as specific sort of constraint satisfaction problem (CSP). In CSP, declarative constraints capture restrictions over variables with finite domains where both the number of variables and their domains are required to be a priori finite. However, the existing formulation of constraint satisfaction problems can be too restrictive to capture design space exploration in many MDE applications with complex structural constraints expressed over the underlying models. In this paper, we interpret flexible and dynamic constraint satisfaction problems directly in the context of models. These extensions allow the relaxation of constraints during a solving process and address problems that are subject to change and require incremental re-evaluation. Furthermore, we present our prototype constraint solver for the domain of graph models built upon the Viatra2 model transformation framework and provide an evaluation of its performance with comparison to related tools.     

Utilizing domain models for application design and validation

Domain analysis enables identifying families of applications and capturing their terminology in order to assist and guide system developers to design valid applications in the domain. One major way of carrying out the domain analysis is modeling. Several studies suggest using metamodeling techniques, feature-oriented approaches, or architectural-based methods for modeling domains and specifying applications in those domains. However, these methods mainly focus on representing the domain knowledge, providing insufficient guidelines (if any) for creating application models that satisfy the domain rules and constraints. In particular, validation of the application models which include application-specific knowledge is insufficiently dealt. In order to fill these lacks, we propose a general approach, called Application-based DOmain Modeling (ADOM), which enables specifying domains and applications similarly, (re)using domain knowledge in application models, and validating the application models against the relevant domain models. In this paper we present the ADOM approach, demonstrating its application to UML 2.0 class and sequence diagrams.