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Stoyan Stoyanov

Bio: Stoyan Stoyanov is an academic researcher from University of Greenwich. The author has contributed to research in topics: Prognostics & Flip chip. The author has an hindex of 12, co-authored 115 publications receiving 598 citations.


Papers
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Journal ArticleDOI
TL;DR: The focus is on providing a structured and comprehensive classification of the existing state-of-the-art PHM approaches, data-driven approaches and algorithms.
Abstract: Prognostics and health management (PHM) has become an important component of many engineering systems and products, where algorithms are used to detect anomalies, diagnose faults and predict remaining useful lifetime (RUL). PHM can provide many advantages to users and maintainers. Although primary goals are to ensure the safety, provide state of the health and estimate RUL of the components and systems, there are also financial benefits such as operational and maintenance cost reductions and extended lifetime. This study aims at reviewing the current status of algorithms and methods used to underpin different existing PHM approaches. The focus is on providing a structured and comprehensive classification of the existing state-of-the-art PHM approaches, data-driven approaches and algorithms.

71 citations

Journal ArticleDOI
TL;DR: Experimental and theoretical results are provided that demonstrate the use of prognostics and health monitoring techniques for high power LEDs subjected to harsh operating conditions.
Abstract: Prognostics is seen as a key component of health usage monitoring systems, where prognostics algorithms can both detect anomalies in the behavior/performance of a micro-device/system, and predict its remaining useful life when subjected to monitored operational and environmental conditions. Light Emitting Diodes (LEDs) are optoelectronic micro-devices that are now replacing traditional incandescent and fluorescent lighting, as they have many advantages including higher reliability, greater energy efficiency, long life time and faster switching speed. For some LED applications there is a requirement to monitor the health of LED lighting systems and predict when failure is likely to occur. This is very important in the case of safety critical and emergency applications. This paper provides both experimental and theoretical results that demonstrate the use of prognostics and health monitoring techniques for high power LEDs subjected to harsh operating conditions.

40 citations

Journal ArticleDOI
TL;DR: In this paper, the results of a packaging process based on the stencil printing of isotropic conductive adhesives (ICAs) that form the interconnections of flip-chip bonded electronic packages are demonstrated.
Abstract: This paper presents the results of a packaging process based on the stencil printing of isotropic conductive adhesives (ICAs) that form the interconnections of flip-chip bonded electronic packages. Ultra-fine pitch (sub-100-mum), low temperature (100degC), and low cost flip-chip assembly is demonstrated. The article details recent advances in electroformed stencil manufacturing that use microengineering techniques to enable stencil fabrication at apertures sizes down to 20mum and pitches as small as 30mum. The current state of the art for stencil printing of ICAs and solder paste is limited between 150-mum and 200-mum pitch. The ICAs-based interconnects considered in this article have been stencil printed successfully down to 50-mum pitch with consistent printing demonstrated at 90-mum pitch size. The structural integrity or the stencil after framing and printing is also investigated through experimentation and computational modeling. The assembly of a flip-chip package based on copper column bumped die and ICA deposits stencil printed at sub-100-mum pitch is described. Computational fluid dynamics modeling of the print performance provides an indicator on the optimum print parameters. Finally, an organic light emitting diode display chip is packaged using this assembly process

33 citations

Proceedings ArticleDOI
09 May 2012
TL;DR: Data driven prognostics methods that take advantage of measured characteristics of individual systems or components in order to predict the remaining useful life (RUL) are focused on.
Abstract: The discipline that connects prognostics and system lifecycle management is often referred to as prognostics and health management (PHM). Though prognostics is one of the main parts of PHM, it is the least mature. This paper is based on the past work of data driven prognostics applied in the field of power electronics modules and primarily concerned with the data driven prognostics methods that take advantage of measured characteristics of individual systems or components in order to predict the remaining useful life (RUL).

29 citations

Journal ArticleDOI
TL;DR: In this paper, an integrated optimisation-modelling computational approach for virtual prototyping is presented to improve the reliability and performance of electronic components and systems through design optimisation at the early product development stage.
Abstract: Purpose – This paper aims to present an integrated optimisation‐modelling computational approach for virtual prototyping that helps design engineers to improve the reliability and performance of electronic components and systems through design optimisation at the early product development stage. The design methodology is used to identify the optimal design of lead‐free (Sn3.9Ag0.6Cu) solder joints in fine‐pitch copper column bumped flip‐chip electronic packages.Design/methodology/approach – The design methodology is generic and comprises numerical techniques for computational modelling (finite element analysis) coupled with numerical methods for statistical analysis and optimisation. In this study, the integrated optimisation‐modelling design strategy is adopted to prototype virtually a fine‐pitch flip‐chip package at the solder interconnect level, so that the thermal fatigue reliability of the lead‐free solder joints is improved and important design rules to minimise the creep in the solder material, exp...

26 citations


Cited by
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Journal ArticleDOI

6,278 citations

Journal ArticleDOI
TL;DR: The review part of this paper specifically focused on the development of hybrid prognostics approaches, attempting to leverage the advantages of combining the progNostics models in the aforementioned different categories for RUL prediction.
Abstract: Prognostics focuses on predicting the future performance of a system, specifically the time at which the system no long performs its desired functionality, its time to failure. As an important aspect of prognostics, remaining useful life (RUL) prediction estimates the remaining usable life of a system, which is essential for maintenance decision making and contingency mitigation. A significant amount of research has been reported in the literature to develop prognostics models that are able to predict a system's RUL. These models can be broadly categorized into experience-based models, date-driven models, and physics-based models. However, due to system complexity, data availability, and application constraints, there is no universally accepted best model to estimate RUL. The review part of this paper specifically focused on the development of hybrid prognostics approaches, attempting to leverage the advantages of combining the prognostics models in the aforementioned different categories for RUL prediction. The hybrid approaches reported in the literature were systematically classified by the combination and interfaces of various types of prognostics models. In the case study part, a hybrid prognostics method was proposed and applied to a battery degradation case to show the potential benefit of the hybrid prognostics approach.

405 citations

Proceedings ArticleDOI
15 Mar 2006
TL;DR: In this article, damage pre-cursors based residual life computation approach for various package elements to prognosticate electronic systems prior to appearance of any macro-indicators of damage has been presented.
Abstract: In this paper, damage pre-cursors based residual life computation approach for various package elements to prognosticate electronic systems prior to appearance of any macro-indicators of damage has been presented. In order to implement the system-health monitoring system, precursor variables or leading indicators-of-failure have been identified for various package elements and failure mechanisms. Model-algorithms have been developed to correlate precursors with impending failure for computation of residual life. Package elements investigated include, first-level interconnects, dielectrics, chip interconnects, underfills and semiconductors. Examples of damage proxies include, phase growth rate of solder interconnects, intermetallics, normal stress at chip interface, and interfacial shear stress

331 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a summary of automated fault detection and diagnostics studies published since 2004 that are relevant to the commercial buildings sector and provide a guideline for selecting an appropriate automated fault detector and diagnostic method.
Abstract: The current article provides a summary of automated fault detection and diagnostics studies published since 2004 that are relevant to the commercial buildings sector. The review updates a previous review conducted in 2004 and published in 2005, and it categorizes automated fault detection and diagnostics methods into three groups. The examples of automated fault detection and diagnostics in the primary category are selectively reviewed to identify various methods that are suitable for building systems and to understand the strengths and weaknesses of the methods. The distribution of studies based on each automated fault detection and diagnostics method and heating, ventilation, and air-conditioning system is also described. Researchers and industries can use the current article as a guideline for selecting an appropriate automated fault detection and diagnostics method.

252 citations