11,249 research outputs found

    An optimal-control based integrated model of supply chain

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    Problems of supply chain scheduling are challenged by high complexity, combination of continuous and discrete processes, integrated production and transportation operations as well as dynamics and resulting requirements for adaptability and stability analysis. A possibility to address the above-named issues opens modern control theory and optimal program control in particular. Based on a combination of fundamental results of modern optimal program control theory and operations research, an original approach to supply chain scheduling is developed in order to answer the challenges of complexity, dynamics, uncertainty, and adaptivity. Supply chain schedule generation is represented as an optimal program control problem in combination with mathematical programming and interpreted as a dynamic process of operations control within an adaptive framework. The calculation procedure is based on applying Pontryagin’s maximum principle and the resulting essential reduction of problem dimensionality that is under solution at each instant of time. With the developed model, important categories of supply chain analysis such as stability and adaptability can be taken into consideration. Besides, the dimensionality of operations research-based problems can be relieved with the help of distributing model elements between an operations research (static aspects) and a control (dynamic aspects) model. In addition, operations control and flow control models are integrated and applicable for both discrete and continuous processes.supply chain, model of supply chain scheduling, optimal program control theory, Pontryagin’s maximum principle, operations research model,

    Establishing The Equipment-methodical Support For Determining The Properties Of Extracts Of Grape Pomace Extracts Produced In The Subcreative Water Environment

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    Research objective: development of a high-pressure reactor for researching the process of extraction of grape pomace by the subcritical water and determining the parameters, providing the maximum yield of various target products – biologically active substances; formation of methodological support for raw material preparation, qualitative and quantitative analysis of extracts, produced by the subcritical extraction. As a result of simulation in the ANSYS system of the stress-strain state of the walls of the reactor chamber and a set of calculation operations, a high-pressure reactor was created that meets the requirements. The formed methodical complex for determining the physicochemical properties of extracts and the content of various biologically active substances included methods for preparing samples and determining the yield of dry extractive substances, evaluation of extraction of polyphenols (tannic-catechol complex), evaluation of extraction of reducing substances, identification furfural and gallic acids, estimation of free organic acids in terms of tartaric acid, evaluation of antioxidant activity of extracts). This methodological complex allows us to estimate the physico-chemical properties of the extracted biologically active substances

    A framework for integrating syntax, semantics and pragmatics for computer-aided professional practice: With application of costing in construction industry

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    Producing a bill of quantity is a knowledge-based, dynamic and collaborative process, and evolves with variances and current evidence. However, within the context of information system practice in BIM, knowledge of cost estimation has not been represented, nor has it been integrated into the processes based on BIM. This paper intends to establish an innovative means of taking data from the BIM linked to a project, and using it to create the necessary items for a bill of quantity that will enable cost estimation to be undertaken for the project. Our framework is founded upon the belief that three components are necessary to gain a full awareness of the domain which is being computerised; the information type which is to be assessed for compatibility (syntax), the definition for the pricing domain (semantics), and the precise implementation environment for the standards being taken into account (pragmatics). In order to achieve this, a prototype is created that allows a cost item for the bill of quantity to be spontaneously generated, by means of the semantic web ontology and a forward chain algorithm. Within this paper, ‘cost items’ signify the elements included in a bill of quantity, including details of their description, quantity and price. As a means of authenticating the process being developed, the authors of this work effectively implemented it in the production of cost items. In addition, the items created were contrasted with those produced by specialists. For this reason, this innovative framework introduces the possibility of a new means of applying semantic web ontology and forward chain algorithm to construction professional practice resulting in automatic cost estimation. These key outcomes demonstrate that, decoupling the professional practice into three key components of syntax, semantics and pragmatics can provide tangible benefits to domain use
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