Papers by virginia ecaterina oltean
The short half-lives of radionuclides used in types of radiopharmaceutical products needed for di... more The short half-lives of radionuclides used in types of radiopharmaceutical products needed for diagnostic imaging or treatment demand a rigorous production planning, in order to assure that high-quality products reach the patients in the required time and the production's radioactive waste is minimized. The paper presents an optimal radiopharmaceuticals production planning system using Constraint Programming (CP). To achieve requirements such as shortest possible production time in safety conditions for the production process, a dual layer control system is proposed: (i) centralized production planning (System Scheduler) and (ii) decentralized SCADA system with distributed intelligence for environment monitoring and control of product making, both layers being integrated in a Holonic Manufacturing Execution architecture (HMES) with multi-agent implementing. Experimental tests were performed on a 19 MeV cyclotron, studying the required products activity dependence on the beam cur...
Lecture Notes in Business Information Processing, 2017
The public transport service system provides safe and secure urban mobility for all citizens. Thi... more The public transport service system provides safe and secure urban mobility for all citizens. This paper describes work-in-progress regarding its role in times of emergency, such as earthquakes, tornadoes, or terrorist attacks. In order to deliver good and safe transport service, it requires adequate resources such as information, staff, property, vehicle, infrastructure, the set of operational rules, and governance. In this perspective, establishing a sustainable and smart transport model to cope with transport services’ disruptions especially for emergency events is vital. A general characterization of critical actions for public transport Emergency Management Planning is provided. A new perspective on designing sustainable public transport services in times of emergency is introduced in order to support transport service company’s operational activities based on sustainable institutions principles.
2017 21st International Conference on System Theory, Control and Computing (ICSTCC), 2017
Starting from a hypothetical open shop production quantity estimation problem with weakly formula... more Starting from a hypothetical open shop production quantity estimation problem with weakly formulated objective function, this paper comparatively discusses a manual heuristic solution and an IBM-ILOG based numerical solution. Problem complexity is managed by specific partitioning strategies in the construction of heuristic solution instances. The study may serve as starting point in the systematic building of a more general heuristic solution method with potential applications in business plan forecasting.
Service Orientation in Holonic and Multi-Agent Manufacturing, 2018
Capacity measurement is of crucial importance in business and manufacturing and is intimately rel... more Capacity measurement is of crucial importance in business and manufacturing and is intimately related to both finite and infinite capacity planning. There is a vast literature on this subject and capacity may be defined in various ways. This paper investigates, within two small scale examples, some issues regarding capacity measurement in a shop floor with multifunctional parallel machines that have to process a specified quantity of products of different types, and with specific operations requirements, in a specified working time. In the first example, each operation type has a specific operation unit time, independently on the working machine, while in the second example each machine can execute any operation from its capabilities portfolio in a unique operation’s unit time, with a unique associated operation unit cost. The study emphasizes, in the first example, that the capacity measurement depends not only on machines capabilities, on products requirements and on the imposed working time, but also on the allocation strategy of groups of machines to groups of products, while the second example shows that, in case of machines with unique operation unit time for all operation types, the maximal number of operations executable in given working time is a valid capacity measure. The discussed examples may serve as starting point for defining capacity planning procedures for more complex scenarios that can be tested using dedicated software tools, targeting industrial applications.
Service Science, 2017
In the context of today’s interconnected world, public higher education is confronted with a shif... more In the context of today’s interconnected world, public higher education is confronted with a shift of its role from public good to public service, which is accompanied by new challenges in building and maintaining the viability of public universities. There is a vast literature on this topic, but there is not yet reported a systematic approach in modeling the basic steps of decision making and problem solving to be completed by a public university to remain viable. Starting from the concepts of service system, and consonance and resonance as key viability conditions, this paper proposes a discrete event model of the viability building and maintaining process in a generic public university organization. The model evolution is driven by events conditioned by internal, external, or mixed causes. Some of the uncontrollable events occurring in the process may drive the discrete evolution to disturbance rejection states, where specific recovery strategies are applied. If recovery is succe...
IFAC-PapersOnLine, 2018
The paper extends the hybrid control for the continuous radiopharmaceuticals production processes... more The paper extends the hybrid control for the continuous radiopharmaceuticals production processes to supervisory control in order to add new functionalities and behavioural modes: optimal offline planning of the production process, adjusting on line the parameters of the process in current execution, and conditioning the process execution by the evolution of the environment context. The present research demonstrates the possibility of applying directly the holonic control paradigm to hybrid supervised control of continuous processes, exemplified by the production of radiopharmaceuticals. The design of an intelligent control solution for this type of processes uses the holonic hybrid supervised control architecture with optimally planned demand sequence which groups demands into commands and orders which are derived from a master product recipe. Implementing solutions are provided.
2016 20th International Conference on System Theory, Control and Computing (ICSTCC), 2016
Constrained models of manufacturing processes frequently provide an integral character of decisio... more Constrained models of manufacturing processes frequently provide an integral character of decision variables, which lead in general to weak duality and suboptimal solutions. Starting from the general transportation paradigm, this paper proposes two network constrained models of a minimum cost manufacturing process for a batch requiring different operations for different products, processed on several identical or different machines. Implications of strong duality are discussed within low-scale examples. Finally an IBM-ILOG implementation solution of a real job shop planning model is presented.
Lecture Notes in Business Information Processing, 2016
Public higher education services receive nowadays intense attention from the society from at leas... more Public higher education services receive nowadays intense attention from the society from at least two perspectives: the high level professional performances requested by companies and public administration as final customers of the educational service system, on one side, and the problem encountered by the authorities in deciding how to dedicate the financial support for universities from the public budget, taking into account also the present state of the labour market and its trend, on another side. Starting from empirical considerations, this paper proposes an ontology model of a generic public higher education service system and several scenarios regarding a qualitative game modelling approach of a Teacher-Student interaction when this service system is placed in an emerging economy and, comparatively, in a mature free market economy.
Revue Roumaine des Sciences Techniques - Serie Électrotechnique et Énergétique
Qualitative models of complex systems recently emerged as useful tools for behaviour prediction i... more Qualitative models of complex systems recently emerged as useful tools for behaviour prediction in case of incomplete system knowledge or as a variant to a difficult analytical analysis. A class of piecewise (PL) differential systems can be abstracted to a logical automaton, within a hybrid control systems (HCS) framework from control engineering, and the resulting discrete evolution provides information about the qualitative behaviours of the continuous system. The basic general models and related design problems were presented in Part I. Part II presents, within a case study, a solution to the problem of constructing a logical automaton as a discrete event abstraction of a PL differential system. Relevant qualitative evolutions are successfully checked against simulated trajectories and future research directions are proposed.
Lecture Notes in Business Information Processing, 2013
This paper presents a proposal concerning the development of a sustainable support for modern edu... more This paper presents a proposal concerning the development of a sustainable support for modern education in services. It accounts for the development of a dedicated higher education study program on Service Science Management and Engineering (SSME) on different levels, i.e. master, undergraduate and compact modules dedicated to a lifelong education process (the SSME education model). The proposed approach addresses both research and curricula development on different service sectors, aiming to foster the new Science of Service at national level.
Studies in Computational Intelligence, 2014
This paper presents a proposal on developing an activity-based generic model of a service system ... more This paper presents a proposal on developing an activity-based generic model of a service system (SSyst) that realises business oriented, IT-based intensive service processes. The approach proposed here to conceive and design the SSyst model takes into consideration the service systems' lifecycle that includes the interactions between the four stakeholders' categories: service provider (with suppliers and service outsourcing), service customer, competition, and compliance bodies (law, financial, environment, a.o.). The high level description of the lifecycle of a service process is used in order to further define, structure and analyze the SSyst model from a triple perspective: (1) the stages of the service's lifecycle; (2) core activities for services; (3) the activity type components of a composite service. The proposed SSyst model is generic, meaning that it can be applied to generate different types of services, ranging from already existent services (that only need to be configured according to the customer needs) to completely new services (that have to be integrated based on the provider's service repository and outsourced services). The services generated in a SSyst type service system must be planned and they must receive resources and capacities optimally allocated for service delivery.
Lecture Notes in Business Information Processing, 2014
Lecture Notes in Business Information Processing, 2014
This paper presents an approach accounting for the classification of the main knowledge resources... more This paper presents an approach accounting for the classification of the main knowledge resources related to the new Science of Service. The main knowledge categories are defined as concepts integrated in an extended Service Science ontology. The ontology derived from several sources was captured using UML and Protégé, and then, through a RDF/OWL transformation, a semantically annotated wiki has been directly implemented offering an execution of the ontology together with implemented use cases. Further, a dedicated application was developed-the Service Science Knowledge Environment (SSKE)in order to grant user access to different knowledge categories created along with the proposed ontology. The SSKE is a cloud based collaborative software service, aiming at providing co-created knowledge resources shared by academia, industry and government organizations. This application can be accessed through the Web (http://sske.cloud.upb.ro/) and it can be used for managing service related knowledge.
Lecture Notes in Computer Science, 2000
ABSTRACT The scenario treated in this paper concerns the discrete event control and supervision o... more ABSTRACT The scenario treated in this paper concerns the discrete event control and supervision of two decoupled continuous systems. The theoretical framework is based on the hybrid control system architecture, developed by P.J. Antsaklis and his co-workers and on the supervised control concept, proposed by the Sylodi Group from Grenoble. The main contribution of this paper is an algorithm for building the discrete event approximation of a continuous system with unknown, constant and constrained parameters. The Antsaklis formalism is extended to a disturbed continuous first order system.
Lecture Notes in Computer Science, 2000
ABSTRACT The research activities carried out in the framework of the proposed paper have been dir... more ABSTRACT The research activities carried out in the framework of the proposed paper have been directed to the development of nonlinear control techniques, algorithms and architectures for the free motion of robots having rigid links, that provide the following global control performances: global asymptotic stability, precision for time varying trajectory tracking, robustness at external disturbances, nonlinear coupling between motion axes and uncertainties of the dynamic model of the manipulator with drives structure, for closed-loop robot systems with n ≥5 degrees of freedom. Thus, there is proposed a solution for nonlinear motion control based on adaptive control techniques. The control method that is proposed provides high dynamic performances for the ensemble manipulator – drive systems – internal transducers – controller – user interface, that is: high displacement speed and tracking precision on desired time varying trajectories, rejection of disturbances of the type: variable masses carried by the arm, modeling errors, measuring noise. In the framework of this paper, the authors designed and simulated a library of procedures, algorithms and software control modules to be further implemented in a generic parallel multiprocessing architecture, as a robot controller. In this respect, the structural design was directed towards VME – based bus oriented multimaster structures.
ArXiv, 2017
In the discrete modeling approach for hybrid control systems, the continuous plant is reduced to ... more In the discrete modeling approach for hybrid control systems, the continuous plant is reduced to a discrete event approximation, called the DES-plant, that is governed by a discrete event system, representing the controller. The observability of the DES-plant model is crucial for the synthesis of the controller and for the proper closed loop evolution of the hybrid control system. Based on a version of the framework for hybrid control systems proposed by Antsaklis, the paper analysis the relation between the properties of the cellular space of the continuous plant and a mechanism of plant-symbols generation, on one side, and the observability of the DES-plant automaton on the other side. Finally an observable discrete event abstraction of the continuous double integrator is presented.
Recently, hybrid automata have emerged as a natural modelling abstraction for biochemical interac... more Recently, hybrid automata have emerged as a natural modelling abstraction for biochemical interactions. Within discrete states, the local dynamics is usually described by linear differential equations, and generically, the continuous variables are protein concentrations. Transitions between discrete states occur, with possible reset variables, when specific threshold values are reached, thus producing abrupt changes in the right hand side of the differential system. This paper firstly analyses a simple hybrid automaton modelling a repressor mechanism in molecular biology, which presents a hysterezis behaviour. Alternate modelling frameworks, limitations of the model and simulation challenges are discussed. Secondly, a second-order piecewise-linear model of a generic biochemical interaction process is abstracted to a Zeno hybrid automaton. A solution for implementation, in MATLAB, of a Zeno path avoidance scheme, based on fixed-step time discretization is proposed and further researc...
behavior, due to the presence of pairs of complex eigenvalues in the spectrum of the system matri... more behavior, due to the presence of pairs of complex eigenvalues in the spectrum of the system matrix, is considered. The control problem consists of damping the oscillations and tracking a piecewise constant reference signal. A control solution is proposed, based on pole placement combined with the internal model principle. Sufficient conditions for the controller existence are deduced and some issues concerning fixed and variable step simulations approaches are discussed. The results are extended to piecewise affine hybrid systems, composed of a set of piecewise affine systems and a switching strategy based on a state space partition.
Control Engineering and Applied Informatics, 2008
There is an increasing interest in the study of genetic regulatory networks, and in addition to e... more There is an increasing interest in the study of genetic regulatory networks, and in addition to experimental tools, specific tools for modelling and simulation recently emerged, allowing systematic behaviour prediction of large complex systems. Since there is a usual lack of information of biochemical reaction networks, qualitative simulation tools, requiring only specification of inequality-like algebraic constraints, are preferred to quantitative ones. Starting from a simple piecewise- linear model of a two genes regulatory network (TGNR) described in the literature, this paper proposes an alternate qualitative modelling technique, which extends a hybrid control systems (HCS) framework from control engineering. The thresholds protein concentrations partition the state space into hyperrectangular open regions and the resulting qualitative model is basically a logical abstraction of the families of continuous trajectories mapped to this partition. The relations of this model to nume...
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Papers by virginia ecaterina oltean