Object-oriented Software Modeling Research Articles

Towards Verifying UML Class Diagram and Formalizing Generalization/Specialization Relationship with Mathematical Set Theory

The Unified Modeling Language (UML) is considered the de facto standard for object-oriented software model development. This makes it appropriate to be used in academia courses at both the graduate and undergraduate levels of education. Some challenges to using the UML is academia are its large number of model concepts and the imprecise semantic of some of these concepts. These challenges are daunting for students who are being introduced to the UML. One approach that can be taken in teaching UML towards addressing these concerns is to limit the number of UML concepts taught and recognize that students may not be able to develop correct UML system models. This approach leads to research work that develop a limited set of UML model concepts that are fewer in number and have more precise semantics. In this paper, we present a new approach to resolve an aspect of this problem by simplifying the generalization/specialization semantics of the class diagram through the application of mathematical formality to usage of these class diagram concepts. Along with that, we discuss the progress of research in the area of verification of UML class models. This research work derives a core set of concepts suitable for graduate and undergraduate comprehension of UML modeling and defines more precise semantics for those modeling concepts. The applicable mathematical principles applied in this work are from the domains of set theory and predicate logic. This approach is particularly relevant for the pedagogy of software engineering and the development of software systems that require a high level of reliability.

Identifying Difficulties of Software Modeling Through Class Diagrams: A Long-Term Comparative Analysis

Software modeling is a creative activity in which software components and their relationships are identified based on customer requirements. Based on the literature, object-oriented software modeling is based on four fundamental pillars which are abstraction, encapsulation, decomposition, and inheritance. However, despite the existence of guidelines and recommendations for implementing the object-oriented approach, novice software designers do not make good design decisions, leading to inefficient designs that cannot be modifiable, understandable, or user-friendly distribute at the development level. The literature reveals that the most common difficulties faced by software designers is a lack of understanding and confusion of concepts related to the object-oriented approach, as well as difficulties in creating Unified Modeling Language diagrams, especially class diagrams. The work presented in this article uses a qualitative and quantitative approach to determine, in a group of university students, what are the most recurrent difficulties and their persistence during the time. The qualitative case study is the method that allowed to generate the documents: <i>diagnostic</i> and <i>evaluation</i> tests. Additionally, a thematic analysis was used to identify, analyze and report patterns within the data. In order to know the occurrences of the problems in the case study, as part of our quantitative approach, a comparative study was applied to compare the results obtained between the diagnostic and evaluation tests and thus establish the similarities and differences among the cases observed, through the hierarchical clustering technique. The findings of this study show us 16 difficulties identified after the qualitative analysis, while the quantitative analysis shows us the number of occurrences and their persistence over time. The difficulties reported in both analyzes focus on these three difficulties: a) Definition of attributes that could be a class, b) Classes with inadequate or insufficient behavior and, c) Incorrect use of multiplicity between classes. Each of these difficulties is analyzed in depth in this study.

Evolution of the Electricity Distribution Networks—Active Management Architecture Schemes and Microgrid Control Functionalities

The power system transition to smart grids brings challenges to electricity distribution network development since it involves several stakeholders and actors whose needs must be met to be successful for the electricity network upgrade. The technological challenges arise mainly from the various distributed energy resources (DERs) integration and use and network optimization and security. End-customers play a central role in future network operations. Understanding the network’s evolution through possible network operational scenarios could create a dedicated and reliable roadmap for the various stakeholders’ use. This paper presents a method to develop the evolving operational scenarios and related management schemes, including microgrid control functionalities, and analyzes the evolution of electricity distribution networks considering medium and low voltage grids. The analysis consists of the dynamic descriptions of network operations and the static illustrations of the relationships among classified actors. The method and analysis use an object-oriented and standardized software modeling language, the unified modeling language (UML). Operational descriptions for the four evolution phases of electricity distribution networks are defined and analyzed by Enterprise Architect, a UML tool. This analysis is followed by the active management architecture schemes with the microgrid control functionalities. The graphical models and analysis generated can be used for scenario building in roadmap development, real-time simulations, and management system development. The developed method, presented with high-level use cases (HL-UCs), can be further used to develop and analyze several parallel running control algorithms for DERs providing ancillary services (ASs) in the evolving electricity distribution networks.

Option for evaluation of development of decision support system requirements

Material relating to the creation of real projects is very rare. To solve this and other problems, the use of end-to-end projects of the semester or course scale was introduced into the process of preparing students. During the project, issues of iterative development of information systems are worked out, where the number of classes and structures is considered to be dozens and design patterns are used. All of them must be coordinated and take their place and role. After each iteration, students have a workable software module. The experience gained gives the student a sense of self-confidence, because he takes part, perhaps for the first time, in the creation of a significant application. Prepared students bring interesting solutions to the project and the role of the teacher is to extend the experience gained to the next year (semester), thereby reducing dependence on experienced professionals. More and more activities are moving to the electronic form, the implementation of the function of estimating the processing of the requirement is becoming easier, so research in this area has prospects. The purpose of the study: the creation of a methodological development for the preparation of students in the field of software engineering. Task: describe ways to ensure the quality of practical classes and the introduction of project technologies in pedagogical activities. Within the framework of the innovative content of education in the disciplines of Object-Oriented Programming, Software Modeling and Design, project technology has been introduced into the educational process. At this time, a unified approach to software development has become very popular. Within the framework of practical classes in each of the disciplines, a separate cross-cutting project is determined, which must be worked out. One or two practical sessions are an iteration of a cross-cutting project that creates new functionality or improves existing one. At the same time, a new construction of the studied programming or a new diagram (document) is being implemented in the project, which is being worked out as a result of the design. In order to improve the quality of training at the end of certain iterations, video recording of the development of the developed part of the project is carried out. Students are divided into groups. The most prepared student leads the development. He fully understands the process and is ready to provide effective assistance in the development of artifacts - one or another diagram (document), or one or another software module. Students work on a chart of artifacts and find out what exactly their group will do, on which artifacts their artifact depends. This affects the time the artifact is first developed. The artifact is proposed for development after a certain readiness of artifacts, on the basis of which the necessary artifact is developed. At the initial iterations it is necessary to make a Development Plan, which records the order of development of artifacts. Software development during video capture is carried out vertically. When building, it is desirable not to change the students during the initial iterations, so that they clearly fix their place of work in the architecture of the project and feel the variable part of their work and the constant part of their work. Implementing end-to-end semester or course projects and using a cloud environment provides significant hands-on experience and a portfolio that students can rely on when looking for work. Suggestions: Involve software companies in the development of the material taught. This can be a project that is created over approximately 18 (9) iterations, with continuous functionality and quality improvements. A project can have an interesting interface, use several programming languages (programming technologies), consist of several parts and have the means of compatibility between its parts and other projects.

Predictive Formal Analysis of Resilience in Cyber-Physical Systems

The behavioral analysis of cyber-physical systems in safety-critical scenarios is a challenging task. In this paper, the endogenous and exogenous aspects of resilience are of cornerstone importance in system design and verification. Endogenous resilience is the inherent ability of the system to detect and process internal faults and malicious attacks. Exogenous resilience is the permanent capability of the system to maintain a safe operation within its ambient environment. In this paper, we present a predictive dual-sided contract-based formal methodology to address both aspects of resilience on top of a distributed object-oriented component-based software model. It is illustrated by a case study of urban drone rescue systems. We exploit the formalism of timed automat a and the toolbox UPPAAL to predict by abstraction and analyze (simulate and verify) endogenous resilience. Instead of presenting the final models of the case study, we reflect our experience with UPPAAL in generic patterns of system design and contract specification, reusable in other contexts with adaptations. The analysis of exogenous resilience is specific to the considered drone rescue system. It consists of synthesizing by iterative model-checking safe flight paths for the drones within a 3D virtual model of urban surroundings true to modern cities.

1st International Workshop on UML Consistency Rules (WUCOR 2015)

The Unified Modeling Language (UML), with its 14 different diagram types, is the de-facto standard modeling language for object-oriented software modeling and documentation. Since the various UML diagrams describe different views of one, and only one, software system under development, they strongly depend on each other in many ways. In other words, the UML diagrams describing a software system must be consistent. Inconsistencies among these diagrams may be a source of faults during software development and analysis. It is therefore paramount that these inconsistencies be detected, analyzed and -- hopefully -- fixed. The goal of this workshop was to gather input and feedbacks on UML consistency rules from the community. This workshop provided an opportunity for researchers who have been working in the area of UML consistency to interact with each other at a highly interactive venue, improve the body of knowledge on UML consistency rules and discuss ideas for further research in this area. This report summarizes details of the workshop and the results obtained that day.

Ontology Based Object-Oriented Domain Modeling

An important step in developing the requirements for an information system is analyzing the application domain. In this step, conceptual models are used for representing an application domain. However, while languages for software design are available and widely used, no generally accepted language exists for conceptual modeling. This work suggests the use of object-oriented software modeling languages also for conceptual modeling. Such use can support a more accurate transition from domain models to software models. As software-modeling languages were not intended for modeling application domains, their constructs lack the required semantics. While previous papers addressed the representation of structural elements of domains using object concepts, this paper addresses behavioral aspects, related to change and interaction. The proposed semantics are based on a mapping between ontological concepts that describe behavior and object-oriented constructs related to dynamics. Based on these mappings, modeling rules are proposed to guide the modeler in creating ontologically well-formed models. The mappings and rules are exemplified using UML and are demonstrated using a case study.

Ontological Modeling Rules for UML: An Empirical Assessment

The Unified Modeling Language (UML) is widely accepted as the de-facto standard for object-oriented information systems (IS) design and software modeling. Recent research has proposed to extend the use of UML to conceptual modeling of application domains. Conceptual models serve both as the basis for communication and domain understanding among analysts, and as the starting point for IS software design. Prior research has proposed a set of modeling rules to provide the analyst or modeler with guidelines for using UML for conceptual modeling.This paper provides an empirical assessment of the benefits derived from using these modeling rules. Using an experimental study involving 53 subjects, it examines the effects of different levels of modeling rule application on application domain understanding. The results show statistically significant differences in the level of domain understanding that was derived from the various models.

Object Modeling of Balanced and Unbalanced Distribution Systems for Power Flow Analysis

Most of the distribution systems are usually unbalanced and radial or near radial (weakly meshed). Presently, the integration of dispersed generations with the distribution system is becoming more popular. This article proposes a new object-oriented software modeling for distribution system power flow analysis. Object-oriented design of radial distribution system, assuming balanced operation, is obtained. Extensibility property of the object-oriented design is exploited to extend the radial system model to weakly meshed system and to incorporate the dispersed generations. The “composition” technique of object-oriented design has been employed to model the unbalanced three-phase system using the objects of balanced system. The modeled objects are implemented in C++ and the robustness of the developed power flow program has been tested for various balanced (10-bus, 33-bus, 69-bus, IEEE 37-bus) and unbalanced (IEEE 13-bus, IEEE 34-bus, IEEE 123-bus) test systems.

Two level control system for FMS - an object oriented approach

This paper present the main results of the research devoted to the simulation, modeling and Two-level Control of Robotics Flexible Manufacturing Systems - FMS. The essential attributes in the paper definition and, consequently, the research accomplished results obtained are the paradigms of object-oriented modeling (in the sense of software engineering) and of distributed intei-ligence (in the sense of systems-control structure and machine intelligence). A simulation model of so-called 'medium scale' as a representative prototype of a Case Study has been developed. For these needs, there has been developed its object-oriented (software) model, the set of communication finite-state automata and a respecti-ve set of control strategies. Program package PETSIM has been applied for the purpose of simulation of the models and of performance evaluation.

Object-oriented modelling and control of flexible conveyor systems for automated assembly

Conveyor systems are one of the commonly used devices for the transportation of parts from one workplace to another in manufacturing systems. In the domain of automated assembly, the requirement to realise a truly Flexible Conveyor System (FCS) can be very demanding and it is difficult to design using conventional design and programming tools. The requirements of an FCS are discussed and the current problems and limitations with conventional implementations are outlined. An object-oriented software model and an integrated design and programming platform are proposed for implementing an FCS to be used in automated assembly applications.

A strategy for mapping from function-oriented software models to object-oriented software models

Because of being in transition or because of choice, many software development environments make use of both the function-oriented and object-oriented approaches in their software development process. In some cases, object-oriented and function-oriented approaches are used in the development of the same system, such as when using function-oriented analysis with object-oriented design, necessitating a transition or mapping from one model to the other. This paper reviews the issues involved in mapping from a function-oriented software model to an object-oriented software model and presents a strategy for accomplishing the mapping in a consistent and partially automatable manner. The effectiveness of the strategy is assessed with four different applications drawn from the literature. It is concluded that the mapping strategy is feasible and reasonably automatable.

Object-oriented software modeling of a Flexible Manufacturing System

Flexible Manufacturing Systems play an important role in improving our manufacturing productivity. Simulation is emerging as a popular tool in modeling FMS for analyzing its performance in the area of production planning/scheduling. In this paper, we illustrate how to model a Flexible Manufacturing System in the object-oriented paradigm using an example. We present a systemtic approach to the design of object-oriented programming systems based on a combination of data modeling and event analysis techniques. An entity relationship approach is used as the basis for an initial decomposition of the system into objects. The design is refined by an analysis of the events the objects participate in. The design is implemented in Objective-C. Finally, we describe ways in which this model of an FMS can be extended to explore popular research questions in production planning and scheduling.

Probabilistic Modelling Of HarmonicCurrents Produced By AC Locomotives

The effective design and analysis of a modern ac electric railway requires a knowledge of system harmonics. Modern locomotives generally contain power electronic drives which generate substantial ac current harmonics. Conventional analysis of these harmonics involves the calculation of worst-case levels from a deterministic calculation. In practice, however, railway operation is such that a wide range of system conditions can exist, with locomotive demand, speed and position all contributing to the harmonic levels. On this basis, probabilistic analysis has been considered to give a more informative overview of system harmonics. Previous researchers have carried out a probabilistic analysis of traction system harmonics, based upon measurements taken from an operating railway. However, such measurements inherently include the combined effects of locomotive demand, speed and position, and to identify the effects of each of these parameters is not an easy task. This paper describes the development of an object-oriented software model used to calculate operating levels for an operating locomotive. The model is used to calculate the input current harmonic levels for an ac, thyristor-bridge, locomotive. A probabilistic analysis of locomotive operation is then developed to give probability functions of demand, speed and position for an example railway. These are used in conjunction with the traction system model to perform a Monte Carlo probabilistic analysis of locomotive harmonics, from which harmonic limits may be derived. Transactions on the Built Environment vol 7, © 1994 WIT Press, www.witpress.com, ISSN 1743-3509 364 Railway Operations