Multi-Input Multi-Output Converter for Universal Power Conversion Operation

This novel converter proposes a Multiple Input and Multiple Output (MIMO) power conversion approach for step-up and step-down processes in AC-DC, DC-DC, AC-AC and DC-AC conversions. This versatile converter is designed by using power electronic switches, for AC-DC and AC-AC conversions thyristors are preferred, whereas DC-DC and DC-AC operations require both turn-on and turn-off control so that transistor (IGBT) is the most suitable switch. The proposed converter is highly recommended for multiple source and multiple output operations, but it can perform one conversion at a time. Power rating of the converter can be up to kilowatts during DC-DC and DC-AC conversions process and AC-AC and AC-DC conversions rating may extend up to megawatts. Simulation model of the MIMO converter is examined in the MATLAB simulink model and the same verified in the real-time test bench model. Conversion in all the stages can be controlled by a digital controller according to the requirement. All four conversions can perform step-up as well as step-down process, so design of inductor and capacitor values are very much important. All four modes of operations for thyristor-based transistors and two diode-based transistors are used to ensure switching operations. Novelty of the research work is conversion of power in all the modes can be bidirectional and also in single-stage process, but in the existing systems of power conversions is a unidirectional process. Proposed single-stage power conversion has more efficiency because of low switching losses. This proposed converter was designed by using mathematical analysis, tested at simulation level and verified in the real-time experiment.

The Conservation of Renewable Resources

Chapter 4 further develops the theory of the conservation of living systems. Natural resource management problems are analyzed using optimal control methods. Natural resources are the state variables of the problem and management instruments are control variables. Management might include harvest, culling, restocking, reseeding, and replanting, or interventions affecting, for example, the fire regime, hydrological flows, the structure of habitats, the functioning of the system, and the ecosystem processes involved. The chapter considers three types of systems: aquatic systems, forest systems, and rangelands. It shows how the methods developed to model conversion/conservation decisions in all cases embed the Hotelling arbitrage condition. It shows how the level of conservation in each type of system is impacted by access rules, and the array of benefits obtained from the system.

A contract-based workflow execution framework for realizing artifact-centric business processes in a dynamic and collaborative environment

Purpose The paper aims to study realization requirements for the flexible enactment of artifact-centric business processes in a dynamic, collaborative environment and to develop a workflow execution framework that can effectively address those requirements. Design/methodology/approach This study proposed a framework and contract-based, event-driven architecture design and implementation that can directly realize collaborative artifact-centric business processes in service-oriented architecture (SOA) without any model conversion. Findings The results show that the approach is feasible in presenting several key benefits over the use of existing workflow systems to run artifact-centric processes. Originality/value Most of the existing approaches require an artifact-centric model to be transformed into executable workflow languages to run on existing workflow management systems. This study argues that the model conversion can incur losses of information and affect traceability and monitoring ability of workflows, especially in an SOA where a workflow can span across multiple inter-business entities.

A Modified Functional Observer-Based EID Estimator for Unknown Continuous-Time Singular Systems

This paper presents the design of a linear quadratic analog tracker (LQAT) based on the observer–Kalman-filter identification (OKID) method and the design of a modified functional observer-based equivalent input disturbance (EID) estimator for unknown square–non-square singular analog systems with unknown input and output disturbances. First, an equivalent mathematical model of the singular analog system is presented to simulate the time response of continuous-time linear singular analog systems to arbitrary inputs via the model conversion method. Then, for the unknown singular analog system, it constructs a linear quadratic analog tracker with state feedback and feed-forward gains based on the off-line OKID method. Furthermore, it extends the design methodology of the EID estimator for strictly proper regular systems with unknown matched–mismatched input and output disturbances to proper regular systems. It is important to mention that the newly developed modified functional observer for proper systems is used to estimate the unknown EID of singular analog systems and that the constraints on the dimensions of unknown disturbances can be eliminated by using the newly proposed EID estimation method. The contributions of this paper can be listed as follows: (1) based on both the OKID method and the discrete-to-continuous model conversion, the simulation of the time responses of the continuous-time linear singular models (which are not feasible using existing MATLAB toolboxes) become feasible; (2) for effective control of the unknown singular analog system, an off-line OKID method is proposed to design an LQAT with state feedback and feed-forward gains; and (3) based on the newly developed modified functional observer for the reduced-order proper regular system, the original EID estimator in the literature is newly extended to estimate the EID from the unknown strictly proper singular analog system, without the original dimensional constraints of the disturbances. It is important to mention that the disturbances of interest can be unknown matched–mismatched input and output disturbances.

FIBER-OPTIC FORCE SENSOR: MATHEMATICAL MODEL, CONVERSION FUNCTION, PROTOTYPE DESIGN

The article considers the problem of the lack of methods for calculating and selecting design parameters when developing and implementing a fiber-optic force sensor (FOFS) as a separate element or component of the system. To solve this problem, we propose to develop a transform function of the power loss of the optical signal from the bending radius of the fiber under the action of applied forces, linking the features of the optical fiberand physico-mechanical parameters of the base on which the fiber is located. Based on the calculations performed, a variant of the FOFS prototype design is proposed.