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(1 - 7 of 7)
- Title
- Control of complex distributed systems with distributed intelligent agents
- Creator
- Tatara, Eric, Cinar, Ali, Teymour, Fouad
- Date
- 2007-06
- Publisher
- ELSEVIER SCI LTD
- Description
-
Control of spatially distributed systems is a challenging problem because of their complex nature, nonlinearity, and generally high order. The...
Show moreControl of spatially distributed systems is a challenging problem because of their complex nature, nonlinearity, and generally high order. The lack of accurate and computationally efficient model-based techniques for large, spatially distributed systems leads to challenges in controlling the system. Agent-based control structures provide a powerful tool to manago distributed systems by utilizing (organizing) local and global information obtained from the system. A hierarchical, agent-based system with local and global controller agents is developed to control networks of interconnected chemical reactors (CSTRs). The global controller agent dynamically updates local controller agent's objectives as the reactor network conditions change. One challenge posed is control of the spatial distribution of autocatalytic species in a network of reactors hosting multiple species. The multi-agent control system is able to intelligently manipulate the network flow rates such that the desired spatial distribution of species is achieved. Furthermore, the robustness and flexibility of the agent-based control system is illustrated through examples of disturbance rejection and scalability with respect to the size of the network.
Endnote format citation for DOI:10.1016/j.jprocont.2006.06.008
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- Title
- Statistical Monitoring of Complex Chemical Processes Using Agent-Based Systems
- Creator
- Perk, Sinem, Teymour, Fouad, Cinar, Ali
- Date
- 2010-06-02
- Publisher
- AMER CHEMICAL SOC
- Description
-
It is highly desirable to have a statistical process monitoring (SPM) system that detects the abnormalities in process operations quickly with...
Show moreIt is highly desirable to have a statistical process monitoring (SPM) system that detects the abnormalities in process operations quickly with as few missed and false alarms as possible while the process operates under various operating conditions An agent-based combined monitoring and fault detection framework is proposed in this study. In this framework, different SPM techniques compete with and complement each other to enhance detection speed and accuracy. SPM techniques from literature such as principal component analysis (PCA), multiblock PCA (MBPCA), and dynamic PCA (DPCA) techniques are implemented in this agent-based process supervision system An agent performance assessment and agent management layer provides dynamic adaptation of the supervision system and improves the performance of SPM The statistical information coming from each of the statistical techniques is summarized through a consensus mechanism The performance of the agent-based consensus mechanism using different consensus criteria is tested for system disturbances of various magnitudes The effectiveness of the proposed agent-based framework with different consensus criteria is evaluated based on fault detection times and missed alarm rates and the adaptation of the supervision system is illustrated
Endnote format citation for DOI:10.1021/ie901368j
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- Title
- Effect of Asymmetric Manipulations in Autocatalytic Networks
- Creator
- Balasubramanian, Sukanya, Cinar, Ali, Teymour, Fouad
- Date
- 2010-06-02
- Publisher
- AMER CHEMICAL SOC
- Description
-
In this paper, we show that heterogeneous networks can be configured and reconfigured to operate in flexible spatial patterns The concept is...
Show moreIn this paper, we show that heterogeneous networks can be configured and reconfigured to operate in flexible spatial patterns The concept is demonstrated by using a square grid of continuous stirred tank reactors with nearest neighbor interactions and hosting multiple cubic autocatalytic species Asymmetry is introduced in the system by allowing for different feed flow rates in the reactors. A heterogeneous system offers expanded phase space, improved stability. and coexistence characteristics The advantages of asymmetry are studied using bifurcation diagrams, continuation studies. and dynamics
Endnote format citation for DOI:10.1021/ie901096v
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- Title
- Estimation of Future Glucose Concentrations with Subject-Specific Recursive Linear Models
- Creator
- Eren-oruklu, Meriyan, Cinar, Ali, Quinn, Lauretta, Smith, Donald
- Date
- 2009-04
- Publisher
- MARY ANN LIEBERT INC
- Description
-
Background: Estimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for...
Show moreBackground: Estimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for early hypoglycemic/hyperglycemic alarms or for adjustment of insulin injections or insulin infusion rates of manual or automated pumps. Continuous glucose monitoring (CGM) technologies provide glucose readings at a high frequency and consequently detailed insight into the subject's glucose variations. The objective of this research is to develop reliable subject-specific glucose prediction models using CGM data. Methods: Two separate patient databases collected under hospitalized (disturbance-free) and normal daily life conditions are used for validation of the proposed glucose prediction algorithm. Both databases consist of glucose concentration data collected at 5-min intervals using a CGM device. Using time-series analysis, low-order linear models are developed from patients' own CGM data. The time-series models are integrated with recursive identification and change detection methods, which enables dynamic adaptation of the model to inter-/intra-subject variability and glycemic disturbances. Prediction performance is evaluated in terms of glucose prediction error and Clarke Error Grid analysis (CG-EGA). Results: Prediction errors are significantly reduced with recursive identification of the models, and predictions are further improved with inclusion of a parameter change detection method. CG-EGA analysis results in accurate readings of 90% or more. Conclusions: Subject-specific glucose prediction strategy has been developed. Including a change detection method to the recursive algorithm improves the prediction accuracy. The proposed modeling algorithm with small number of parameters is a good candidate for installation in portable devices for early hypoglycemic/hyperglycemic alarms and for closing the glucose regulation loop with an insulin pump.
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- Title
- Agent-based control of spatially distributed chemical reactor networks
- Creator
- Tatara, Eric, North, Michael, Hood, Cindy, Teymour, Fouad, Cinar, Ali
- Date
- 2005
- Publisher
- SPRINGER-VERLAG BERLIN
- Description
-
Large-scale spatially distributed systems provide a unique and difficult control challenge because of their nonlinearity, spatialdistribution...
Show moreLarge-scale spatially distributed systems provide a unique and difficult control challenge because of their nonlinearity, spatialdistribution and generally high order. The control structure for these systems tend to be both discrete and distributed as well and contain discrete and continuous elements. A layered control structure interfaced with complex arrays of sensors and actuators provides a flexible supervision and control system that can deal with local and global challenges. An adaptive agent-based control structure is presented whereby local control objectives may be changed in order to achieve the global control objective. Information is shared through a global knowledge environment that promotes the distribution of ideas through reinforcement. The performance of the agent-based control approach is illustrated in a case study where the interaction front between two competing autocatalytic species is moved from one spatial configuration to another. The multi-agent control system is able to effectively explore the parameter space of the network and intelligently manipulate the network flow rates such that the desired spatial distribution of species is achieved.
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- Title
- Control of grade transitions in distributed chemical reactor networks - An agent-based approach
- Creator
- Tetiker, M. Derya, Artel, Arsun, Teymour, Fouad, Cinar, Ali
- Date
- 2008-09-26
- Publisher
- PERGAMON-ELSEVIER SCIENCE LTD
- Description
-
Supervision of distributed manufacturing processes producing different grades of a product requires intelligent reconfiguration strategies...
Show moreSupervision of distributed manufacturing processes producing different grades of a product requires intelligent reconfiguration strategies during grade transition phases to minimize off-spec production. Agent-based approaches are ideal for such problems and they provide flexible, robust, and emergent solutions during dynamically changing process conditions. Three different multi-layered multi-agent, frameworks are proposed for the supervision of grade transitions in autocatalytic reactor networks. The first framework is the centralized framework and it is useful for small-scale grade transitions where only a small region of the network needs to be reconfigured. Alternatively, the other two frameworks use a decentralized approach. The first decentralized framework implements genetic algorithms and the second one uses self-organizing heuristics and auctions for large-scale grade transitions. The case studies demonstrate that as the complexity of the reconfiguration problem increases, decentralized solutions perform more efficiently.
Endnote format citation for DOI:10.1016/j.compchemeng.2008.02.008
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- Title
- Adaptive control strategy for regulation of blood glucose levels in patients with type 1 diabetes
- Creator
- Eren-oruklu, Meriyan, Cinar, Ali, Quinn, Lauretta, Smith, Donald
- Date
- 2009-09
- Publisher
- ELSEVIER SCI LTD
- Description
-
Current insulin therapy for patients with type 1 diabetes often results in high variability in blood glucose concentrations and may cause hype...
Show moreCurrent insulin therapy for patients with type 1 diabetes often results in high variability in blood glucose concentrations and may cause hype rglycemic/hypoglycemic episodes. Closing the glucose control loop with a fully automated electro-mechanical pancreas will improve the quality of life for insulin-dependent patients. An adaptive control algorithm is proposed to keep glucose concentrations within normoglycemic range and dynamically respond to glycemic challenges. A model-based control strategy is used to calculate the required insulin infusion rate, while the model parameters are recursively tuned. The algorithm handles delays associated with insulin absorption, time-lag between subcutaneous and blood glucose concentrations, and variations in inter/intra-subject glucose-insulin dynamics. Simulation results for simultaneous meat and physiological disturbances are demonstrated for subcutaneous insulin infusion.
Endnote format citation for DOI:10.1016/j.jprocont.2009.04.004
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