Dov Dori

ERP modeling: a comprehensive approach

We present a generic reverse engineering process, aimed at developing a model that captures the available alternatives at different application levels of an Enterprise Resource Planning (ERP) system. Such a model is needed when ERP systems are aligned with the needs of the enterprise in which they are implemented. In order to support the ERP implementation process, the model should describe the entire scope of the ERP systems functionality and the alternative business processes it supports, as well as the interdependencies among them. We analyze the desired properties a modeling language should satisfy to be applied in constructing an ERP system modal. This analysis, which follows the Cooperative Requirements Engineering With Scenarios classification framework in its adapted ERP modeling form, results in a set of criteria for evaluating modeling languages for this purpose. Using these criteria, we evaluate the Object-Process modeling Methodology and apply it for generating a detailed ERP system model. The generic process and detailed criteria we develop can serve for comprehensive ERP modeling, as well as for obtaining a model of other process-supportive off-the-shelf systems that are of generic and configurable nature.

Sparse pixel vectorization: an algorithm and its performance evaluation

Accurate and efficient vectorization of line drawings is essential for their higher level processing. We present a thinningless sparse pixel vectorization (SPV) algorithm. Rather than visiting all the points along the wires black area, SPV sparsely visits selected medial axis points. The result is a crude polyline, which is refined through polygonal approximation by removing redundant points. Due to the sparseness of pixel examination and the use of a specialized data structure, SPV is both time efficient and accurate, as evaluated by our proposed performance evaluation criteria.

A protocol for performance evaluation of line detection algorithms

Abstract.Accurate and efficient vectorization of line drawings is essential for any higher level processing in document analysis and recognition systems. In spite of the prevalence of vectorization and line detection methods, no standard for their performance evaluation protocol exists. We propose a protocol for evaluating both straight and circular line extraction to help compare, select, improve, and even design line detection algorithms to be incorporated into line drawing recognition and understanding systems. The protocol involves both positive and negative sets of indices, at pixel and vector levels. Time efficiency is also included in the protocol. The protocol may be extended to handle lines of any shape as well as other classes of graphic objects.

The model multiplicity problem: experimenting with real-time specification methods

The object-process methodology (OPM) specifies both graphically and textually the systems static-structural and behavioral-procedural aspects through a single unifying model. This model singularity is contrasted with the multimodel approach applied by existing object oriented system analysis methods. These methods usually employ at least three distinct models for specifying various system aspects: mainly structure, function, and behavior. Object modeling technique (OMT), the main ancestor of the unified modeling language (UML), extended with timed statecharts, represents a family of such multimodal object oriented methods. Two major open questions related to model multiplicity vs. model singularity have been: 1) whether or not a single model, rather than a combination of several models, enables the synthesis of a better system specification; and 2) which of the two alternative approaches yields a specification that is easier to comprehend. The authors address these questions through a double-blind controlled experiment. To obtain conclusive results, real time systems, which exhibit a more complex dynamic behavior than nonreal time systems were selected as the focus of the experiment. We establish empirically that a single model methodology, OPM, is more effective than a multimodel one, OMT, in terms of synthesis. We pinpoint specific issues in which significant diiferences between the two methodologies were found. The specification comprehension results show that there were significant differences between the two methods in specific issues.

A syntactic geometric approach to recognition of dimensions in engineering machine drawings

Abstract An algorithm for recognizing dimensions in engineering machine drawings that employs a syntactic/geometric approach along with a specific deterministic finite automation (DFA) is presented and demonstrated. First, the problem of distinguishing object from interpretation lines is addressed. Then, dimension-sets, their components, kinds, and types are defined and illustrated. A DFA called the dimension-set profiler is used to determine the profile of a given dimension-set. The resulting profile is used to obtain a sketch which is parsed by the dimensioning grammar to yield a conceptual web. This web, in turn, is converted into a geometric web by substituting components labeling nodes by their line description. These line descriptions are compared to the lines in the actual dimension-set. A certain degree of redundancy is introduced to ascertain valid recognition.

Situation-Based Access Control: Privacy management via modeling of patient data access scenarios

Access control is a central problem in privacy management. A common practice in controlling access to sensitive data, such as electronic health records (EHRs), is Role-Based Access Control (RBAC). RBAC is limited as it does not account for the circumstances under which access to sensitive data is requested. Following a qualitative study that elicited access scenarios, we used Object-Process Methodology to structure the scenarios and conceive a Situation-Based Access Control (SitBAC) model. SitBAC is a conceptual model, which defines scenarios where patients data access is permitted or denied. The main concept underlying this model is the Situation Schema, which is a pattern consisting of the entities Data-Requestor, Patient, EHR, Access Task, Legal-Authorization, and Response, along with their properties and relations. The various data access scenarios are expressed via Situation Instances. While we focus on the medical domain, the model is generic and can be adapted to other domains.

Aligning an ERP system with enterprise requirements: An object-process based approach

One of the main problems in ERP implementation projects is how to align an off-the-shelf software package with the business processes of the enterprise implementing it. The paper proposes a requirement-driven approach, which benefits from reusing the business process design without being restricted by predefined solutions and criteria. The approach applies an iterative alignment process, which employs an algorithm that matches a model of the enterprise requirements with a model of the ERP system capabilities. The algorithm identifies possible matches between the two models and evaluates the gaps between them despite differences in their completeness and detail level. It provides the enterprise with a set of feasible combinations of requirements that can be satisfied by the ERP system as a basis for making implementation decisions. We use Object-Process Methodology (OPM) to model both the ERP system and the enterprise requirements, and utilize the pair of resulting OPM models as input for the matching algorithm. The alignment algorithm has been tested in an experimental study, whose encouraging results demonstrate the ability of the approach to provide a satisfactory solution to the problem of aligning an ERP software package with an enterprise business model.

Modelling Off-the-Shelf Information Systems Requirements: An Ontological Approach

Requirements for choosing off-the-shelf information systems (OISR) differ from requirements for development of new information systems in that they do not necessarily provide complete specifications, thus allowing flexibility in matching an existing IS to the stated needs. We present a framework for OISR conceptual models that consists of four essential elements: business processes, business rules, information objects and required system services. We formalise the definitions of these concepts based on an ontological model. The ontology-based OISR model provides a framework to evaluate modelling languages on how appropriate they are for OISR requirements specifications. The evaluation framework is applied to the Object-Process Methodology, and its results are compared with a similar evaluation of ARIS. This comparison demonstrates the effectiveness of the ontological framework for evaluating modelling tools on how well they can guide selection, implementation and integration of purchased software packages.

Why significant UML change is unlikely

Reform may be too little too late to spare software engineers the cognitively overwhelming effort of applying UML to modeling system structure and behavior in a truly unified manner.

Vector-based arc segmentation in the machine drawing understanding system environment

Arcs are important primitives in engineering drawings. Extracting these primitives during the lexical analysis phase is a prerequisite to syntactic and semantic understanding of engineering drawings within the machine drawing understanding system. Bars are detected by the orthogonal zig-zag vectorization algorithm. Some of the detected bars are linear approximations of arcs. As such, they provide the basis for arc segmentation. An arc is detected by finding a chain of bars and a triplet of points along the chain. The arc center is first approximated as the center of mass of the triangle formed by the intersection of the perpendicular bisectors of the chords these points define. The location of the center is refined by recursively finding more such triplets and converging to within no more than a few pixels from the actual arc center after two or three iterations. The high performance of the algorithm, demonstrated on a set of real engineering drawings, is due to the fact that it avoids both raster-to-vector and massive pixel-level operations, as well as any space transformations. >