Declarative Modelling

We consider a dynamic vehicle routing problem in which a fleet of service vehicles pay preventive maintenance visits to a set of spatially distributed customers over a given time horizon. Each vehicle follows a pre-planned separate route which links points defined by customer location and service periods. Customer orders and the feasible time windows for the execution of those orders are dynamically revealed over time. The objective is to maximize the number of new urgent requests, which are inserted dynamically throughout the assumed time horizon, but not at the expense of the already accepted orders. The question that must be considered is whether the newly reported service request and the correction of the fulfillment date of the already submitted request can be accepted or not. Problems of this type arise, for example, in systems in which preventive or corrective maintenance requests are scheduled to follow periodically performed inspections or repairs. The problem under consideration is formulated as a constraint satisfaction problem using the ordered fuzzy number formalism, which allows to handle the fuzzy nature of the variables involved through an algebraic approach. The computational results show that the proposed solution outperforms the commonly used computer simulation methods.

We consider a dynamic vehicle routing problem in which a fleet of service vehicles pay preventive maintenance visits to a set of spatially distributed customers over a given time horizon. Each vehicle follows a pre-planned separate route which links points defined by customer location and service periods. Customer orders and the feasible time windows for the execution of those orders are dynamically revealed over time. The objective is to maximize the number of new urgent requests, which are inserted dynamically throughout the assumed time horizon, but not at the expense of the already accepted orders. The question that must be considered is whether the newly reported service request and the correction of the fulfillment date of the already submitted request can be accepted or not. Problems of this type arise, for example, in systems in which preventive or corrective maintenance requests are scheduled to follow periodically performed inspections or repairs. The problem under consideration is formulated as a constraint satisfaction problem using the ordered fuzzy number formalism, which allows to handle the fuzzy nature of the variables involved through an algebraic approach. The computational results show that the proposed solution outperforms the commonly used computer simulation methods.

The paper's objective concerns assessing a mesh-like supply network of periodically acting local transportation modes from the perspective of possible rescheduling the multimodal flows of jobs assigned to certain technological routes passing through common shared workstations. The considered reference model of a Material Transportation Network (MTN), where several heterogeneous means of material handling, e.g. AGVs, hoists, lifts, etc., interact with each other via common shared workstations, enables the formulation of scheduling and rescheduling tasks in the context of a Periodic Vehicle Routing Problem. The main problem is in essence to identify conditions guaranteeing transient period free rescheduling of cyclic steady state flows of multimodal processes and local transportation processes supporting their execution. Such sufficient conditions allows one to replace the exhaustive search for the admissible flows control by design of regular structure material handling system, i.e. to solve the considered class of rescheduling problems online. The proposed methodology behind rescheduling cyclic steady state production flows executed in regular-structure MTNs is clarified through multiple illustrative examples.

In declarative process models, a process is described as a set of rules as opposed to a set of permitted flows. Oftentimes, such rulebased notations are more concise than their flow-based cousins; however, that conciseness comes at a cost: It requires computation to work out which flows are in fact allowed by the rules of the process. In this paper, we present an algorithm to solve the Activity Reachability problems for the declarative Condition Response (DCR) graphs notation: the problem given a DCR graph and a task, say "Payout reimbursement", to find a flow allowed by the graph that ends with the execution of that task. Existing brute-force solutions to this problem are generally unhelpful already at medium-sized graphs. We present here a genetic algorithm solving Activity Reachability. We evaluate this algorithm on a selection of DCR graphs, both artificial and from industry, and find that on the real-world examples, the genetic algorithm invariably outperforms the brute-force solutions by two orders of magnitude.

The paper's objective concerns assessing a mesh-like supply network of periodically acting local transportation modes from the perspective of possible rescheduling the multimodal flows of jobs assigned to certain technological routes passing through common shared workstations. The considered reference model of a Material Transportation Network (MTN), where several heterogeneous means of material handling, e.g. AGVs, hoists, lifts, etc., interact with each other via common shared workstations, enables the formulation of scheduling and rescheduling tasks in the context of a Periodic Vehicle Routing Problem. The main problem is in essence to identify conditions guaranteeing transient period free rescheduling of cyclic steady state flows of multimodal processes and local transportation processes supporting their execution. Such sufficient conditions allows one to replace the exhaustive search for the admissible flows control by design of regular structure material handling system, i.e. to solve the considered class of rescheduling problems online. The proposed methodology behind rescheduling cyclic steady state production flows executed in regular-structure MTNs is clarified through multiple illustrative examples.

The paper's objective concerns assessing a mesh-like supply network of periodically acting local transportation modes from the perspective of possible rescheduling the multimodal flows of jobs assigned to certain technological routes passing through common shared workstations. The considered reference model of a Material Transportation Network (MTN), where several heterogeneous means of material handling, e.g. AGVs, hoists, lifts, etc., interact with each other via common shared workstations, enables the formulation of scheduling and rescheduling tasks in the context of a Periodic Vehicle Routing Problem. The main problem is in essence to identify conditions guaranteeing transient period free rescheduling of cyclic steady state flows of multimodal processes and local transportation processes supporting their execution. Such sufficient conditions allows one to replace the exhaustive search for the admissible flows control by design of regular structure material handling system, i.e. to solve the considered class of rescheduling problems online. The proposed methodology behind rescheduling cyclic steady state production flows executed in regular-structure MTNs is clarified through multiple illustrative examples.

This paper describes a Grid-like Material Transportation Network (GMTN) in which several heterogeneous means of transportation (Automated Guided Vehicles (AGVs), hoists, lifts, etc.) interact with each other via common shared workstations to provide a variety of demand-responsive material handling operations. Different material handling transport modes provide movement of workpieces between workstations along their manufacturing routes in the GMTN and they can be seen as processes realized with synergic utilization of various local periodically acting unimodal processes. The main contribution of this research is the solution of a constraint satisfaction problem addressing AGVs fleet match-up scheduling subject to GMTN and fuzzy operation time constraints. In the presented case both production rate (production takt) and operations execution time are described by imprecise (fuzzy) data. In other words, the research's objective concerns assessing grid-like networks of periodically acting local transportation modes from the perspective of possible mass-customized oriented requirements imposed on scheduling of multimodal flows of jobs assigned to certain technological routes passing through common shared workstations.

Declarative Modelling environments exhibit an idiosyncrasy that demands specialised machine learning methodologies. The particular characteristics of the datasets, their irregularity in terms of class representation, volume, availability as well as user induced inconsistency further impede the learning potential of any employed mechanism, thus leading to the need for adaptation and adoption of custom approaches, expected to address these issues. In the current work we present the problems encountered in the effort to acquire and apply user profiles in such an environment, the modified boosting learning algorithm adopted and the corresponding experimental results.

As a provider of Electronic Case Management solutions to knowledgeintensive businesses and organizations, the Danish company Exformatics has in recent years identified a need for flexible process support in the tools that we provide to our customers. We have addressed this need by adapting DCR Graphs, a formal declarative workflow notation developed at the IT University of Copenhagen. Through close collaboration with academia we first integrated execution support for the notation into our existing tools, by leveraging a cloud-based process engine implementing the DCR formalism. Over the last two years we have taken this adoption of DCR Graphs to the next level and decided to treat the notation as a product of its own by developing a stand-alone web-based collaborative portal for the modelling and simulation of declarative workflows. The purpose of the portal is to facilitate end-user discussions on how knowledge workers really work, by enabling collaborative simulation of processes. In earlier work we reported on the integration of DCR Graphs as a workflow execution formalism in the existing Exformatics ECM products. In this paper we report on the advances we have made over the last two years, we describe the new declarative process modelling portal, discuss its features, describe the process of its development, report on the findings of an initial evaluation of the usability of the tool, resulting from a tutorial on declarative modelling with DCR Graphs that we organized at last years BPM conference and present our plans for the future.

Declarative Modelling environments exhibit an idiosyncrasy that demands specialised machine learning methodologies. The particular characteristics of the datasets, their irregularity in terms of class representation, volume, availability as well as user induced inconsistency further impede the learning potential of any employed mechanism, thus leading to the need for adaptation and adoption of custom approaches, expected to address these issues. In the current work we present the problems encountered in the effort to acquire and apply user profiles in such an environment, the modified boosting learning algorithm adopted and the corresponding experimental results.

In this paper we illustrate an integrated Computational Intelligence technique using machine learning and evolutionary search methods for the automation of qualitative aspects acquisition and implementation in conceptual design of 3D scene synthesis. The aim is to alleviate the task of adapting a scene to the particularities of a certain morphological or other intuitive demands while obeying a given set of functional, financial or other requirements. The approach comprises a knowledge obtainment stage, where the machine learning mechanism acquires the style implications of the morphology of a series of examples, and a generation stage, where the evolutionary mechanism conducts a partial exploration of the solution space of scenes compliant to the given set of requirements. The paradigm domain where the study of such a mechanism is placed is that of building design defined through declarative modeling by hierarchical decomposition.

Computer-Aided Declarative Design systems are focused at the early phase of design, the conceptual phase, employing declarative modelling in order to provide the user with tools and techniques aiming to capture his/her intuition and better expression of his/her mental ideas. In this paper, we argue that within this process, the introduction of the notion of concept could assist the description phase by offering the designer prior knowledge structures. In order to support concept representation and organization, we propose a specific ontology. We extend previous work, focusing on the representation of concepts in CADD systems by developing a subsystem that also deals with concept definition, evolution, ontology re-arrangement and we analyse its incorporation in CADD system architecture. As a domain example, we refer to Architecture.

Declarative Modelling environments exhibit an idiosyncrasy that demands specialised machine learning methodologies. The particular characteristics of the datasets, their irregularity in terms of class representation, volume, availability as well as user induced inconsistency further impede the learning potential of any employed mechanism, thus leading to the need for adaptation and adoption of custom approaches, expected to address these issues. In the current work we present the problems encountered in the effort to acquire and apply user profiles in such an environment, the modified boosting learning algorithm adopted and the corresponding experimental results.

Contemporary building design problems are inherently complex and require multiple designers to work collaboratively. This paper presents the development and evaluation of an effective collaborative design environment which facilitates designers to exchange and share information
through the WWW/Internet during the development of architectural projects. In particular, the implementation of the web-base system concerns the Collaborative Declarative Modelling System framework (CDMS) as an extension of MultiCAD software architecture. This CDMS framework is
based on a specific module (DCM) that was designed in order to exploit the declarative model content in the implementation of the collaborative mechanism. We present the appropriate Web-based collaborative workspace developed as a MultiCAD Client. Finally is presented a typical case study process by the developed prototype system and its formal operation.

Computer-Aided Declarative Design systems are focused at the early phase of design, the conceptual phase, employing declarative modelling in order to provide the user with tools and techniques aiming to capture his/her intuition and better expression of his/her mental ideas. In this paper, we argue that within this process, the introduction of the notion of concept could assist the description phase by offering the designer prior knowledge structures. In order to support concept representation and organization, we propose a specific ontology. We extend previous work, focusing on the representation of concepts in CADD systems by developing a subsystem that also deals with concept definition, evolution, ontology re-arrangement and we analyse its incorporation in CADD system architecture. As a domain example, we refer to Architecture.