The Experts below are selected from a list of 43077 Experts worldwide ranked by ideXlab platform

Pingfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • Time-Dependent Reliability Analysis in Operation: Prognostics and Health Management
    Engineering Design under Uncertainty and Health Prognostics, 2019
    Co-Authors: Chao Hu, Byeng D. Youn, Pingfeng Wang
    Abstract:

    Over the past few decades, rapid adoption of sensing, computing, and communications technologies has created one of the key capabilities of modern Engineered Systems: the ability to—at a low cost—to gather, store, and process large volumes of sensor data from an Engineered System during operation.

  • Enabling Resilience of Complex Engineered Systems Using Control Theory
    IEEE Transactions on Reliability, 2018
    Co-Authors: Nita Yodo, Pingfeng Wang, Melvin Rafi
    Abstract:

    Successful recovery from a disrupted state to maintain optimal performance is a key feature that a resilient complex Engineered System should have. In the engineering design community, the current focus of engineering resilience research is primarily directed toward improving overall System performance in the presence of likelihood failures. Little attention has been given to the study of how the System responds during and/or after the occurrence of a failure event. This paper proposes the use of control theory as a strategy to enable resilient behavior in complex Engineered Systems. Control theory has various benefits in its application to a resilient Engineered System, with the main advantage being its ability to regulate and govern System states, even while the failure is taking place. In the context of implementation within a complex Engineered System, such a controller should be designed such that, when a disturbance occurs, the controller should simultaneously be able to take timely action to correct the shift in System performance. To date, the fusion of control theory with engineering resilience has not been explored in-depth by the engineering design community. This paper, thus, presents a resilience modeling and analysis approach using fundamental control theory. The resilience of a power distribution System is employed as a case study to demonstrate the effectiveness of the proposed approach. The presented study also expects to aid in the concurrent development of resilience functions in complex Engineered Systems under uncertainty.

  • a nested extreme response surface approach for time dependent reliability based design optimization
    Journal of Mechanical Design, 2012
    Co-Authors: Zequn Wang, Pingfeng Wang
    Abstract:

    A primary concern in practical engineering design is ensuring high System reliability throughout a product's lifecycle, which is subject to time-variant operating conditions and component deteriorations. Thus, the capability of dealing with time-dependent probabilistic constraints in reliability-based design optimization (RBDO) is of vital importance in practical engineering design applications. This paper presents a nested extreme response surface (NERS) approach to efficiently carry out time-dependent reliability analysis and determine the optimal designs. This approach employs the kriging model to build a nested response surface of time corresponding to the extreme value of the limit state function. The efficient global optimization (EGO) technique is integrated with the NERS approach to extract the extreme time responses of the limit state function for any given System design. An adaptive response prediction and model maturation (ARPMM) mechanism is developed based on the mean square error (MSE) to concurrently improve the accuracy and computational efficiency of the proposed approach. With the nested response surface of time, the time-dependent reliability analysis can be converted into the time-independent reliability analysis, and existing advanced reliability analysis and design methods can be used. The NERS approach is compared with existing time-dependent reliability analysis approaches and integrated with RBDO for Engineered System design with time-dependent probabilistic constraints. Two case studies are used to demonstrate the efficacy of the proposed NERS approach.

  • Resilience Allocation for Engineered System Design
    53rd AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference<BR>20th AIAA ASME AHS Adaptive Structures Conference<BR&g, 2012
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ life-cycle costs (LCCs). Recent years have seen a surge of interest and tremendous advance in prognostics and health management (PHM) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a resilience allocation problem (RAP) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System reliability-based design optimization (RBDO) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

  • Resilience Allocation for Resilient Engineered System Design
    Journal of Institute of Control Robotics and Systems, 2011
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System RBDO (Reliability-Based Design Optimization) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

Byeng D. Youn - One of the best experts on this subject based on the ideXlab platform.

  • Time-Dependent Reliability Analysis in Operation: Prognostics and Health Management
    Engineering Design under Uncertainty and Health Prognostics, 2019
    Co-Authors: Chao Hu, Byeng D. Youn, Pingfeng Wang
    Abstract:

    Over the past few decades, rapid adoption of sensing, computing, and communications technologies has created one of the key capabilities of modern Engineered Systems: the ability to—at a low cost—to gather, store, and process large volumes of sensor data from an Engineered System during operation.

  • A newly formulated resilience measure that considers false alarms
    Reliability Engineering and System Safety, 2017
    Co-Authors: Joung Taek Yoon, Minji Yoo, Byeng D. Youn, Yunhan Kim
    Abstract:

    Engineering resilience is a measure of a System's ability to maintain its functionality by resisting and recovering from adverse events. Although false alarms often occur in engineering practice, existing quantitative measures of engineering resilience do not consider false alarms. This makes it difficult to estimate the true degree of resilience and impedes efforts to design a resilient Engineered System. This paper thus proposes a new resilience measure that considers false alarms. Two types of false alarms, Type I (false fault) and Type II (false health), are considered and quantified based upon conditional probability theory. A new resilience measure, which considers false alarm rates and reliability, is then formulated in a probabilistic manner. Compared to the conventional resilience measure, the newly formulated resilience measure can estimate System resilience more rigorously and accurately. The effectiveness of the proposed resilience measure is demonstrated via numerical and electro‐hydrostatic actuator case studies.

  • Statistical Health Reasoning of Water-Cooled Power Generator Stator Bars Against Moisture Absorption
    IEEE Transactions on Energy Conversion, 2015
    Co-Authors: Byeng D. Youn, Joung Taek Yoon, Chao Hu, Kyung Min Park, Beom Chan Jang
    Abstract:

    The power generator is typically maintained with a time- or usage-based strategy, which could result in a substantial waste of remaining useful life, high maintenance cost, and low plant availability. Recently, the field of prognostics and health management offers diagnostic and prognostic techniques to precisely assess the health condition and robustly predict the remaining useful life (RUL) of an Engineered System, with an aim to address the aforementioned deficiencies. This paper explores a smart health reasoning System to assess the health condition of power generator stator bars against moisture absorption based on the statistical analysis of the capacitance measurements on bar insulators. In particular, a relative health measure, namely the directional Mahalanobis distance, is proposed to quantify the health condition of a stator bar. The smart health reasoning System is validated using five years' field data from seven generators, each of which contains 42 turns.

  • Resilience Allocation for Engineered System Design
    53rd AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference<BR>20th AIAA ASME AHS Adaptive Structures Conference<BR&g, 2012
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ life-cycle costs (LCCs). Recent years have seen a surge of interest and tremendous advance in prognostics and health management (PHM) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a resilience allocation problem (RAP) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System reliability-based design optimization (RBDO) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

  • Resilience Allocation for Resilient Engineered System Design
    Journal of Institute of Control Robotics and Systems, 2011
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System RBDO (Reliability-Based Design Optimization) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

Joung Taek Yoon - One of the best experts on this subject based on the ideXlab platform.

  • A newly formulated resilience measure that considers false alarms
    Reliability Engineering and System Safety, 2017
    Co-Authors: Joung Taek Yoon, Minji Yoo, Byeng D. Youn, Yunhan Kim
    Abstract:

    Engineering resilience is a measure of a System's ability to maintain its functionality by resisting and recovering from adverse events. Although false alarms often occur in engineering practice, existing quantitative measures of engineering resilience do not consider false alarms. This makes it difficult to estimate the true degree of resilience and impedes efforts to design a resilient Engineered System. This paper thus proposes a new resilience measure that considers false alarms. Two types of false alarms, Type I (false fault) and Type II (false health), are considered and quantified based upon conditional probability theory. A new resilience measure, which considers false alarm rates and reliability, is then formulated in a probabilistic manner. Compared to the conventional resilience measure, the newly formulated resilience measure can estimate System resilience more rigorously and accurately. The effectiveness of the proposed resilience measure is demonstrated via numerical and electro‐hydrostatic actuator case studies.

  • Statistical Health Reasoning of Water-Cooled Power Generator Stator Bars Against Moisture Absorption
    IEEE Transactions on Energy Conversion, 2015
    Co-Authors: Byeng D. Youn, Joung Taek Yoon, Chao Hu, Kyung Min Park, Beom Chan Jang
    Abstract:

    The power generator is typically maintained with a time- or usage-based strategy, which could result in a substantial waste of remaining useful life, high maintenance cost, and low plant availability. Recently, the field of prognostics and health management offers diagnostic and prognostic techniques to precisely assess the health condition and robustly predict the remaining useful life (RUL) of an Engineered System, with an aim to address the aforementioned deficiencies. This paper explores a smart health reasoning System to assess the health condition of power generator stator bars against moisture absorption based on the statistical analysis of the capacitance measurements on bar insulators. In particular, a relative health measure, namely the directional Mahalanobis distance, is proposed to quantify the health condition of a stator bar. The smart health reasoning System is validated using five years' field data from seven generators, each of which contains 42 turns.

  • Resilience Allocation for Engineered System Design
    53rd AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference<BR>20th AIAA ASME AHS Adaptive Structures Conference<BR&g, 2012
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ life-cycle costs (LCCs). Recent years have seen a surge of interest and tremendous advance in prognostics and health management (PHM) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a resilience allocation problem (RAP) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System reliability-based design optimization (RBDO) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

  • Resilience Allocation for Resilient Engineered System Design
    Journal of Institute of Control Robotics and Systems, 2011
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System RBDO (Reliability-Based Design Optimization) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

Chao Hu - One of the best experts on this subject based on the ideXlab platform.

  • Decision Making under Uncertainty for Design of Resilient Engineered Systems
    Reliability Engineering & System Safety, 2019
    Co-Authors: Cameron A. Mackenzie, Chao Hu
    Abstract:

    Abstract Designing resilient Engineered Systems that can sense and withstand adverse events and recover from the effects of the adverse events is increasingly seen as an important goal of engineering design. This paper proposes a value-driven design for resilience (VD2R) framework in order to enable the assessment of System resilience and the optimization of decision variables (or design characteristics) that maximize the value of the System for a firm. The VD2R framework possesses three unique features that allow System resilience and value to be addressed in a theoretically founded and explicit way. First, it assesses the time-dependent resilience of an Engineered System by explicitly modeling the redundancy, robustness, and restoration of the System. This assessment captures the stochastic behavior of degradation and restoration and their impact on System resilience. Second, it encompasses a value model that links time-dependent System resilience to a design firm's future profit. Third, the VD2R framework offers an efficient optimization method to solve high-dimension, mixed-integer decision-making models. The proposed framework is demonstrated with a case study, where the resilience of a series-parallel System is modeled and its design characteristics optimized.

  • Time-Dependent Reliability Analysis in Operation: Prognostics and Health Management
    Engineering Design under Uncertainty and Health Prognostics, 2019
    Co-Authors: Chao Hu, Byeng D. Youn, Pingfeng Wang
    Abstract:

    Over the past few decades, rapid adoption of sensing, computing, and communications technologies has created one of the key capabilities of modern Engineered Systems: the ability to—at a low cost—to gather, store, and process large volumes of sensor data from an Engineered System during operation.

  • Optimizing Resilience When Designing Engineered Systems
    Volume 2A: 43rd Design Automation Conference, 2017
    Co-Authors: Chao Hu, Cameron A. Mackenzie
    Abstract:

    Engineering design increasingly seeks to design resilient Systems that can withstand adverse events and recover from the effects of the adverse events. The value-driven design for resilience (VD2R) framework enables the assessment of System resilience and the optimization of decision variables (or design characteristics) that maximize the value of the System for a firm. The VD2R framework it assesses the time-dependent resilience of an Engineered System by explicitly modeling the redundancy, robustness, and recoverability of the System. This assessment captures the uncertain behavior of degradation and restoration and their impact on System resilience. Second, it encompasses a value model that links time-dependent System resilience to a design firm’s future profit. The firm can consider the trade-offs between designing a more resilient but costly System and generating less profit after the System is fielded. It facilitates the understanding of how resilience adds value to a firm, a key enabler for determining the optimal level of System resilience. The proposed framework is demonstrated with an illustrative case study, where the resilience of a series-parallel System is modeled and its design characteristics optimized.

  • Statistical Health Reasoning of Water-Cooled Power Generator Stator Bars Against Moisture Absorption
    IEEE Transactions on Energy Conversion, 2015
    Co-Authors: Byeng D. Youn, Joung Taek Yoon, Chao Hu, Kyung Min Park, Beom Chan Jang
    Abstract:

    The power generator is typically maintained with a time- or usage-based strategy, which could result in a substantial waste of remaining useful life, high maintenance cost, and low plant availability. Recently, the field of prognostics and health management offers diagnostic and prognostic techniques to precisely assess the health condition and robustly predict the remaining useful life (RUL) of an Engineered System, with an aim to address the aforementioned deficiencies. This paper explores a smart health reasoning System to assess the health condition of power generator stator bars against moisture absorption based on the statistical analysis of the capacitance measurements on bar insulators. In particular, a relative health measure, namely the directional Mahalanobis distance, is proposed to quantify the health condition of a stator bar. The smart health reasoning System is validated using five years' field data from seven generators, each of which contains 42 turns.

  • Resilience Allocation for Engineered System Design
    53rd AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference<BR>20th AIAA ASME AHS Adaptive Structures Conference<BR&g, 2012
    Co-Authors: Byeng D. Youn, Pingfeng Wang, Chao Hu, Joung Taek Yoon
    Abstract:

    Most Engineered Systems are designed with high levels of System redundancies to satisfy required reliability requirements under adverse events, resulting in high Systems’ life-cycle costs (LCCs). Recent years have seen a surge of interest and tremendous advance in prognostics and health management (PHM) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a resilience allocation problem (RAP) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the System reliability-based design optimization (RBDO) and the System PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

Michelle C. Laplaca - One of the best experts on this subject based on the ideXlab platform.

  • thermoreversible laminin functionalized hydrogel for neural tissue engineering
    Journal of Biomedical Materials Research Part A, 2006
    Co-Authors: Sarah Elizabeth Stabenfeldt, Andrés J. García, Michelle C. Laplaca
    Abstract:

    Traumatic injury to the central nervous System (CNS) triggers cell death and deafferentation, which may activate a cascade of cellular and network disturbances. These events often result in the formation of irregularly shaped lesions comprised of necrotic tissue and/or a fluid-filled cavity. Tissue engineering represents a promising treatment strategy for the injured neural tissue. To facilitate minimally invasive delivery of a tissue Engineered System, a thermoreversible polymer is an attractive scaffold candidate. We have developed a bioactive scaffold for neural tissue engineering by tethering laminin-1 (LN) to methylcellulose (MC), a thermoresponsive hydrogel. The base MC chain was oxidized via sodium m-periodate to increase MC tethering capacity. Protein immobilization was facilitated by a Schiff base reaction between primary amine groups on LN and the carbonyl groups of the oxidized MC chain. Immunoassays demonstrated tethering of LN at 1.6 ± 0.5 ng of LN per milligram of MC. Rheological measurements for different MC–LN constructs indicated MC composition- and MC treatment-dependent effects on solution–gelation transition temperature. Cellular assays with primary rat cortical neurons demonstrated enhanced cell adhesion and viability on LN-functionalized MC when compared with base and oxidized MC. This bioadhesive thermoresponsive scaffold may provide a robust delivery vehicle to injured CNS tissue for neural cell transplantation strategies. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006

  • Thermoreversible laminin‐functionalized hydrogel for neural tissue engineering
    Journal of Biomedical Materials Research Part A, 2006
    Co-Authors: Sarah Elizabeth Stabenfeldt, Andrés J. García, Michelle C. Laplaca
    Abstract:

    Traumatic injury to the central nervous System (CNS) triggers cell death and deafferentation, which may activate a cascade of cellular and network disturbances. These events often result in the formation of irregularly shaped lesions comprised of necrotic tissue and/or a fluid-filled cavity. Tissue engineering represents a promising treatment strategy for the injured neural tissue. To facilitate minimally invasive delivery of a tissue Engineered System, a thermoreversible polymer is an attractive scaffold candidate. We have developed a bioactive scaffold for neural tissue engineering by tethering laminin-1 (LN) to methylcellulose (MC), a thermoresponsive hydrogel. The base MC chain was oxidized via sodium m-periodate to increase MC tethering capacity. Protein immobilization was facilitated by a Schiff base reaction between primary amine groups on LN and the carbonyl groups of the oxidized MC chain. Immunoassays demonstrated tethering of LN at 1.6 ± 0.5 ng of LN per milligram of MC. Rheological measurements for different MC–LN constructs indicated MC composition- and MC treatment-dependent effects on solution–gelation transition temperature. Cellular assays with primary rat cortical neurons demonstrated enhanced cell adhesion and viability on LN-functionalized MC when compared with base and oxidized MC. This bioadhesive thermoresponsive scaffold may provide a robust delivery vehicle to injured CNS tissue for neural cell transplantation strategies. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006