Object-oriented Model Research Articles

Observer of changes in the forest of the shortest paths on dynamic graphs of transport networks

The purpose of the work is the development of basic data structures, speed-efficient and memoryefficient algorithms for tracking changes in predefined decisions about sets of shortest paths on transport networks, notifications about which are received by autonomous coordinated transport agents with centralized or collective control. A characteristic feature of transport operations is the independence and asynchrony of the emergence of perturbations of optimal solutions, as well as the lack of global influence of individual perturbations on the set of all processes on the network. This clearly determines the feasibility of realizing the idea of reoptimizing existing solutions in real time as information is received about disturbances in the structure and parameters of the transport network, various restrictions on the use of existing shortest paths. In contrast to the classical problems of finding shortest paths on static or dynamic graphs, it is proposed to supplement the set of situations controlled by the observer by taking into account the associations of shortest path trees with agents that actually use such paths. This will improve the responsiveness of agent notification processes for timely switching to a new path. The space of search states is a dynamically generated bipartite sparse graph of the transport network, represented by a list of arcs. The basic algorithm for finding the shortest paths uses Dijkstra's scheme, but implements a bootstrapping method to generate the search result. The compactness of the representation of the observed forest of shortest paths is achieved by mapping individual trees of such a forest onto the projection of tree vertices in memory, where the position of each vertex corresponds to the distance from the tree root. The proposed version of the construction of the search procedure is based on the mechanisms existing in database management systems for creating different relational representations of the physical data model. This eliminates the need to solve technological problems of complexing heterogeneous models of dynamic transport networks, memory allocation. As a result, the specification of various rules for the logistics of transport operations is simplified, since such operations in terms of object-oriented models are easily determined by polymorphic classes of transitions between nodes of the transport network.

Client-server application framework based on an object-oriented network model

The relationship between the business layer and the underlying data access layers is considered. The disadvantages of the traditional approach based on the relational database and the data access layer (DAO/ORM) are analyzed. A document-oriented database with built above it an object-oriented network model of data presentation is proposed. The integration with the business layer, automatic assembly of business objects using Java reflection without additional specifications, polymorphic storage and transfer of business entities in collections of the document-oriented database is supported.

Thermal Performance Visualization Using Object−Oriented Physical and Building Information Modeling

This study demonstrates the research and development of a visualization method called thermal performance simulation. The objective of this study is providing the results of thermal performance simulation results into building information modeling (BIM) models, displaying a series of thermal performance results, and enabling stakeholders to use the BIM tool as a common user interface in the early design stage. This method utilizes a combination of object-oriented physical modeling (OOPM) and BIM. To implement the suggested method, a specific BIM authoring tool called the application programming interface (API) was adopted, as well as an external database to maintain the thermal energy performance results from the OOPM tool. Based on this method, this study created a prototype called the thermal energy performance visualization (TEPV). The TEPV translates the information from the external database to the thermal energy performance indicator (TEPI) parameter in the BIM tool. In the TEPI, whenever BIM models are generated for building design, the thermal energy performance results are visualized by color-coding the building components in the BIM models. Visualization of thermal energy performance results enables non-engineers such as architects to explicitly inspect the simulation results. Moreover, the TEPV facilitates architects using BIM as an interface in building design to visualize building thermal energy performance, enhancing their design production at the early design stages.

Функціональна організація системи підтримки прийняття рішень організаційного управління

The paper is devoted to the implementation of an approach to designing anobject-oriented decision support system for automating organizational management processes. The structure of such a system is based on the problem-independent components of the presentation of the subject area of the organizational and technical system, on the basis of which the decision maker implements the functional tasks of organizational management. On the basis of the principles of object-oriented modeling, sets of information classes of objects of the vocabulary of a subject domain are selected, which make it possible to construct an object information model of a specific subject area of an ADSS application object. The information technology platform for the creation of the ADSS is considered, which requires such an organizational and functional structure of the software environment in which the objects of the subject area and the relationships between them are determined independently of the implementation of functional tasks of data processing in the procedures and interfaces of the system, and represent a single structure. As a result, afunctional ADSS organization was proposed in the form of a unified informationenvironment for constructing a computer organizational management system that implements monitoring of production indicators of organizational and technical system entities, in particular, the electricity market.Ref. 15, pic. 2

A constraint-based approach for optimizing the design of overhead lines

The use of computational methods in engineering design is a long-standing issue. Several mathematical approaches have been investigated in the literature to support the design optimization of engineering products. Most of them are focused on the optimization of a single structure, without considering a system of structures. The design of supports for electric lines requires tools for the management and sizing of a system of structures that interacts with each other under specific load conditions. This paper deals with a framework to support the design optimization of an overhead line using methods related to the theory of the Constraint Satisfaction Problem. The object-oriented model of a transmission line has been described and then implemented into a prototypical software platform. The parameters to be considered as variables are defined by the designer at the beginning of the optimization process. These variables are geometrical dimensions, poles locations, cable pre-tension, etc. The set of constraints is related to normative, climate conditions, datasheets, material limits, and expert knowledge. To demonstrate the effectiveness of this approach, a case study has been developed considering a variable number of constraints and parameters. In particular, the case study is focused on the design of a low-voltage sub-network between two distribution substations.

SIMULATION AND EXPRESSION OF ATMOSPHERIC POLLUTION DISPERSION PROCESS BASED ON 3D GRID

Abstract. Aiming at the problems existing on the expression of atmospheric pollution dispersion, a data model of state-oriented and object-oriented hybrid modeling is designed. The model supports true three-dimensional grid representation and cellular automata deduction, and can combine the calculation and deduction of atmospheric pollution to improve the accuracy and efficiency of the model. The simulation experiments of single source and multi-source pollutants are carried out. The results show that: the model conforms to the diffusion law of atmospheric pollution. The pollutant concentration at any time, section or space in the whole diffusion process can be calculated and expressed dynamically, which improves the accuracy, rapidity, intuitiveness and analysation of the deduction of atmospheric pollutant diffusion process.

ПАРАМЕТРИЗМ В ДИЗАЙНІ. СПОСОБИ МОДЕЛЮВАННЯ ТА НАПРЯМКИ РОЗВИТКУ

Мета дослідження полягає у розгляді поняття «параметризм» в дизайні, виявленні його способів моделювання та можливих напрямків розвитку. Отримані результати можуть бути використані для уточнення теоретичної бази параметричного проектування і вдосконалення відповідних алгоритмів проектного процесу. Методи дослідження. В процесі дослідження були застосовані історико-порівняльний та хронологічний методи, а також метод термінологічного аналізу, що сприяло виявленню термінологічних трактувань щодо параметричного конструювання, асоціативної геометрії і об’єктно-орієнтованого моделювання, як способів створення параметризованої геометричної моделі, а також розгляду інших суміжних понять в контексті параметричного проектування. Наукова новизна роботи полягає в комплексному дослідженні цифрових перетворень дизайну на сучасному етапі в контексті теоретико-методологічних концепцій, зокрема щодо параметричного проектування. Висновки. Розглянутий у статті термін «параметризм» має достатнє теоретичне опрацювання. Його практичне втілення за допомогою параметричного моделювання ґрунтується на трьох основних способах створення геометричної моделі: параметричному конструюванні (Parametric design), що передбачає використання різних видів взаємозв’язків між елементами моделі; асоціативної геометрії (Associative geometry), спрямованої на забезпечення єдиного інформаційного взаємозв’язку між геометричною моделлю та іншими компонентами бази даних проекту і об’єктно- орієнтованого моделювання (Feature-based modeling), за допомогою якого визначається поведінка геометричної форми при подальших змінах. Можливі напрямки розвитку параметризму охоплюють щорічні міжнародні виставки і конкурси, де демонструються об’єкти дизайну, виконані за допомогою параметричного моделювання. Все частіше з’являються освітні програми, орієнтовані на параметричне проектування, але найбільш актуальним є удосконалення спеціалізованого програмного забезпечення.

Rule-Based Object-Oriented Water Resource System Simulation Model for Water Allocation

Simulation is a basic method to analyze water resources system and provide information for decision-making. In this study, a framework is presented that describes the basic elements in a water resource system and a modelling technique integrating conceptual simulation and rule control. To formulate the process of the water cycle and water exploitation with a mathematical model, the water system is described based on adjustable relevant rules and respective parameters with experiences and pragmatic demands in the framework. The rule set describes the principles required to design conceptual networks and control the concrete processes of movement and conversion of different water flows. Combined with object-oriented programming, different calculation functional modules are classified based on the characteristics of water source layers, and the processes that occur in the networks are realised in the computation. The influence of the South-to-North Water Diversion project on the Haihe River basin is analysed by the rule-based object-oriented water resource allocation simulation model. According to the simulation results, groundwater extraction will be reduced by 6,181 million m3. The relationship between water source replacement and water layer exchange in the Haihe River basin is analysed, and the feasibility of the model is verified. Based on the rule-based model, the user requirements can be taken into account conveniently, and the rules are flexible to adjust with experiences and real conditions. This model can be used to simulate complex water resource systems.

Timber beam in virtual furnace

Purpose This paper aims to present a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. Temperatures calculated inside the timber beam are compared to measured values from the fire test. Design/methodology/approach The paper presents a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. The presented part lies in a virtual furnace which simulates temperature environment around tested elements in the furnace. Comparison of results show good agreement in the case when burning of timber is included in the numerical model. Findings The virtual furnace presented in this paper allows to calculate temperature environment around three timber beams. After validation of the fire dynamics simulator (FDS) model, the temperature conditions are passed to the FE model which solves heat transfer to the tested element. Temperatures inside the timber beam which are solved in software Atena Science are compared to measured temperatures from the fire test. The comparison of temperatures in three control points shows good accuracy of the calculation in the point closer to the heated edge. An inaccuracy is shown in points located deeper in the beam cross-section – below the char layer. Research limitations/implications In conclusion, the virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by object-oriented finite element model (OOFEM). The interconnection of both software is made owing to MuPIF python library. Practical implications The virtual furnace takes advantage of great possibilities of computational fluid dynamics code FDS. The model is based on an accurate representation of a real fire furnace of fire laboratory PAVUS a.s. located in the Czech Republic. It includes geometry of the real furnace, material properties of the furnace linings, burners, ventilation conditions and tested elements. Gas temperature calculated in the virtual furnace is validated to temperatures measured during a fire test. Social implications The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. Originality/value The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by OOFEM. The interconnection of both software is made thanks to MuPIF python library.

Experience with Teaching Different Modeling Techniques on the example of Glucose Insulin Regulation Model.

In order to teach different modeling techniques we demonstrate equation-based, block-schema based, compartment and component-based modeling using acausal and object-oriented modeling language - Modelica. Hands-on implementation using all these techniques and comparing them towards same system (in our case glucose-insulin regulation) we teach pros and cons of each technique. Equation-based or block-schema based may be rapidly implemented from literature. However, compartment based or component-based models brings better understanding of modeled reality. When students have such experience, they tend to assess published papers more critically and do more complex system analysis.

General-Purpose Object-Oriented Framework for Vorticity-Dominated Flow Simulation

This paper describes the development of a computational framework for aerodynamic simulations based on the unsteady vortex lattice method under the object-oriented programming paradigm. The effort aims to fulfill the fluid-dynamics portion of the fluid–structure interaction problem in the multiphysics field. The construction and implementation of an object-oriented model is introduced along with its analysis and design stages, focusing on the generality and versatility. The overall class organization is presented, and the main classes’ characteristics are discussed. The software validation indicates that the transient and the steady-state aerodynamics for the impulsively started motion of a body are accurately captured by the simulations. In addition, comparisons against experimental results show that rotors in hover flight are acceptably represented for small angles of attack of the blades, within the limitations of the flat-plate representation and the inviscid hypothesis of the model. Regarding applications, six different models are analyzed: 1) a single propeller rotor, 2) a small-scale quadcopter drone, 3) a flying-wing drone, 4) a joined-wing aircraft, 5) a drag-reduction system for cars, and, 6) a flapping-wing insect. In all cases, the results indicate that a well-tuned simulation based on vorticity-dominated flows is widely suitable for the aerodynamic study of several cases. All simulations expose the main advantages of a modular object-oriented program: the ability to change the case of analysis with minimal reprogramming, and the flexibility to link with different models in a co-simulation strategy.

Integrated modelling of built environment and functional requirements: Implications for resilience

The built environment is a core part of most healthcare systems, involving a number of requirements such as those related to space and patients’ well-being. However, these are usually addressed separately from other functional requirements, resulting in designs that do not support resilient performance. This study proposes a framework for the integrated modelling of built environment and other functional requirements, relying on two approaches: Functional Resonance Analysis Method (FRAM), and Building Information Modelling (BIM). Requirements are defined as equivalent to the precondition aspect of FRAM functions. BIM allows the creation of a database of requirements and functions, linked to an object-oriented model of the built environment. The proposed framework was devised and tested in an intensive care unit. Findings shed light on the necessary resilience to cope with the gap between built environment-as-imagined in design and built environment-as-done due to performance adjustments. This type of resilience may have a long-lasting nature, as many built environment attributes cannot be easily changed.

Simulation of differential-algebraic equation systems with optimization criteria embedded in Modelica

Differential-algebraic equations with embedded optimization criteria (DAEO) are a class of mathematical models for underdetermined differential-algebraic equation (DAE) systems with less algebraic equations than algebraic variables. The algebraic variables may be calculated as the solution of an embedded (non)linear program, yielding a DAEO system. An example for DAEOs is the dynamic flux balance analysis (DFBA) approach, where the formulation of metabolic reaction networks leads to an underdetermined equation system for the intracellular fluxes that are assumed to behave optimally with respect to some cell-specific optimization criterion.We present a toolbox that allows formulation of DAEOs in the object-oriented Modelica modeling language. The solution method is based on substituting the embedded optimization problem with its first-order Karush-Kuhn-Tucker conditions to obtain a nonsmooth DAE system that can be simulated by a root-finding DAE solver. One nonlinear example and two examples based on DFBA demonstrate the performance of the toolbox.

GEOINFORMATION SUPPORT FOR AUTOMATED TEST PLANNING SUBSYSTEM

The process of testing weapons and military equipment involves numerous manual labor-intensive operations. Such operations can be simplified by fully or partially automating the test planning stages, conducting them directly, and processing the test results. Feature of testing weapons and military equipment is the large amount of data that somehow has a spatial location. One of the modern tools of cartographic representation, processing and analysis of statistical data arrays that have spatial localization, geospatial modeling and situation forecasting is the technology of geoinformation systems.
 The article substantiates the feasibility of using geoinformation systems as part of the weapons testing system and military equipment. The functional scheme of integration of the geoinformation component into the structure of the test automation subsystem is presented for geoinformation support of the processes of testing planning and processing of measurement results. An approach to the creation of geoinformation models of test sites is proposed, based on the use of methods of remote sensing of land and open Web-GIS resources. The list of functional modules of spatial data processing and analysis, which can be applied to the tasks of testing, is distributed in the geoinformation toolkit. Examples of typical spatial tasks that can be performed during test planning, direct testing, processing, and analysis of measurement results, if such data are spatially linked.
 The use of geoinformation technology in the test system will provide an arsenal of qualitatively new methods of digital cartography, such as the technology of automated preparation of cartographic information in the accepted cartographic projections and symbols, mass processing of arrays of measured data, a wide toolkit of mathematical and cartographic methods and functions, features and functions own methods, algorithms and methods of statistical information processing, create and use object-oriented geoinformation data models, operate with a set of visualization tools for the best presentation of research and simulation results.

Design and Implementation of P2P Based Mobile App for Collaborative Learning in Higher Education

Within the recent years, mobile technologies have made major progress in its de-velopment. They have become an integral part of our daily life. Therefore, the big interest of using mobile technology in education process is comprehensible. A new technology was born called mobile learning (m-learning). The main benefits of this technology is sharing three important dimensions of learning resources namely learning contents, learning collaborators and learning services. In univer-sity courses, different forms of collaborative and peer learning are progressively used in order to assist students meet an assortment of learning outcomes. There-fore, the use of mobile technologies in education has become a crucial topic for research. Because mobile phone is the first choice of everyone to communicate, our research is focused on the use of smartphones as learning resources. In this paper, we propose an implementation of a new mobile application based peer-to-peer learning system named "EachOther" and a scenario for its usage applied on students of an IT course at the High School of Technology of Fez (ESTF). The aim of this work consists of the conception, the development and the implementa-tion of the mobile application based on Android system to support collaborative learning, by applying an object-oriented modeling language which is Unified Modeling Language (UML).

Hierarchy of Grid Partition (HGP) Integrating data in Software Engineering and databases

Hierarchy is a method of forming a system into grouping data in a database, while to integrate some data into an integrated data system in software engineering, there needs to be an appropriate method so that the data does not occur in an integrated system. In addition to making it easier to know the object attributes of a data, it is necessary to create a partition method, after we can do data integration with the grid method, then the combination of several methods becomes a new method, the Hierarchy of Grid Partition (HGP) Method. The purpose of the Hierarchy of Grid Partition (HGP) method is to integrate the data of an engineering software and database, in order to facilitate the user in finding the data needed and not duplicate the data. To develop this method, there needs to be design tools such as object-oriented modeling which is a unified modeling language (UML). The function of the Hierarchy of Grid Partition (HGP) method makes it easy to find data, because all data has been formed in a data partition grid system, the conclusion of this method is that the data access system is more effective and efficient.

Predicting population displacements after earthquakes

ABSTRACT An agent-based object-oriented model for household displacements is presented and used to analyze household decision-making after a hypothetical earthquake in the City of Vancouver, Canada. Temporary displacements and permanent relocation are accounted for. The model for households include considerations of socioeconomic demographics, social networks, and disaster preparedness. The analysis results indicate that nearly 70,000 persons are expected to be displaced by the earthquake. Of those, close to 19,000 will need public sheltering. In addition, nearly 40,000 persons are expected to relocate in the years following the earthquake. Among the displaced persons, occupants of multi-family pre-code and low-code buildings are over-represented. Among those needing public shelter or relocation, there is a disproportionately high number of renters and low-income households. The models in this paper can help the development of pre-disaster plans by suggesting optimal location of public shelters, and by identifying decisions that reduce the number of households relocating.

Simulation and semi-physical verification of fuel metering unit model for turboshaft aeroengine

When modeling an aeroengine control system, effects of fuel metering unit are neglected or oversimplified, which most probably leads to unreliable simulation or experimental results. In order to well understand influences of fuel metering unit on performance of an aeroengine and to enrich the component-level model of a turboshaft aeroengine, a stepping motor controlled fuel metering unit is examined by combining process-based modeling and object-oriented modeling and is employed in the component-level engine model. Performances of the engine with and without the fuel metering unit are compared by simulation. The component-level engine model with the fuel metering unit characteristics considered meets the simulation requirements on the steady precision and can describe dynamics of the engine more precisely. A semi-physical experimental verification is implemented to confirm the influence of the fuel metering unit. The results show that simulation using the component-level engine model with the fuel metering unit sub-model is in accordance with the experiment, and that comparing to the engine model without fuel metering unit, the model with a fuel metering unit can extend the performance parameter response dozens of milliseconds.

Fvsoomm a Fuzzy Vectorial Space Model and Method of Personality, Cognitive Dissonance and Emotion in Decision Making

The purpose of this extension of the ESM’2019 conference paper is to propose some means to implement an artificial thinking model that simulates human psychological behavior. The first necessary model is the time fuzzy vector space model (TFVS). Traditional fuzzy logic uses fuzzification/defuzzification, fuzzy rules and implication to assess and combine several significant attributes to make deductions. The originality of TFVS is not to be another fuzzy logic model but rather a fuzzy object-oriented model which implements a dynamic object structural, behavior analogy and which encapsulates time fuzzy vectors in the object components and their attributes. The second model is a fuzzy vector space object oriented model and method (FVSOOMM) that describes how-to realize step by step the appropriate TFVS from the ontology class diagram designed with the Unified Modeling Language (UML). The third contribution concerns the cognitive model (Emotion, Personality, Interactions, Knowledge (Connaissance) and Experience) EPICE the layers of which are necessary to design the features of the artificial thinking model (ATM). The findings are that the TFVS model provides the appropriate time modelling tools to design and implement the layers of the EPICE model and thus the cognitive pyramids of the ATM. In practice, the emotion of cognitive dissonance during buying decisions is proposed and a game addiction application depicts the gamer decision process implementation with TFVS and finite state automata. Future works propose a platform to automate the implementation of TFVS according to the steps of the FVSOOMM method. An application is a case-based reasoning temporal approach based on TFVS and on dynamic distances computing between time resultant vectors in order to assess and compare similar objects’ evolution. The originality of this work is to provide models, tools and a method to design and implement some features of an artificial thinking model.

Flexible watershed simulation with the Raven hydrological modelling framework

A general formulation of a surface water hydrological model is posed that enables multiple numerical schemes, model structures, discretization schemes, and interpolation approaches to be tested, compared, and/or used for assessment of structural uncertainty and algorithm skill. This formulation is the basis for the object-oriented and open source hydrological modelling framework Raven. Raven is uniquely capable of fully emulating and then modifying or extending a number of existing hydrological models of differing design, including the UBC watershed model, GR4J, MOHYSE, HMETS, and HBV-EC. More than 100 compatible process algorithm options and more than 80 interchangeable options for both routing and the estimation of forcings support the testing of trillions of possible model configurations. It supports general spatial discretization, including grids, subbasin/hydrologic response units, lumped, or triangulated irregular network models. Raven’s utility for examining the impact of model choices and sensitivity to structural model uncertainty is demonstrated with a set of simple test cases.