Bongtae Han

Prof. Bongtae Han

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Academic Career Length

37Years (1990-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 July 2004 in Optics Letters
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Journal Article
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Zhaoyang WangZhaoyang Wang
Zhaoyang Wang
BHBongtae Han
Bongtae Han
An advanced random phase-shifting algorithm to extract phase distributions from randomly phase-shifted interferograms is proposed. The algorithm is based on a least-squares iterative procedure, but it copes with the limitation of the existing iterative algorithms by separating a frame-to-frame iteration from a pixel-to-pixel iteration. The algorithm provides stable convergence and accurate phase extraction with as few as three interferograms, even when the phase shifts are completely random. The algorithm is simple, fast, and fully automatic. A computer simulation is conducted to prove the concept.
8 August 2014 in IEEE Transactions on Power Electronics
Verified
Journal Article
Closed access
HOHyunseok Oh
Hyunseok Oh
BHBongtae Han
Bongtae Han
PMPatrick McCluskey
Patrick McCluskey
CHChangwoon Han
Changwoon Han
BYByeng D. Youn
Byeng D. Youn
Recent growth of the insulated gate bipolar transistor (IGBT) module market has been driven largely by the increasing demand for an efficient way to control and distribute power in the field of renewable energy, hybrid/electric vehicles, and industrial equipment. For safety-critical and mission-critical applications, the reliability of IGBT modules is still a concern. Understanding the physics-of-failure of IGBT modules has been critical to the development of effective condition monitoring (CM) techniques as well as reliable prognostic methods. This review paper attempts to summarize past developments and recent advances in the area of CM and prognostics for IGBT modules. The improvement in material, fabrication, and structure is described. The CM techniques and prognostic methods proposed in the literature are presented. This paper concludes with recommendations for future research topics in the CM and prognostics areas.
29 July 2019 in Energies
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Journal Article
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WDWEIPING DIAO
WEIPING DIAO
Saurabh SaxenaSaurabh Saxena
Saurabh Saxena
BHBongtae Han
Bongtae Han
Michael Gerard PechtMichael Gerard Pecht
Michael Gerard Pecht
Lithium-ion batteries typically exhibit a transition to a more rapid capacity fade trend when subjected to extended charge–discharge cycles and storage conditions. The identification of the knee point can be valuable to identify the more severe degradation trend, and to provide guidance when scheduling battery replacements and planning secondary uses of the battery. However, a concise and repeatable determination of a knee point has not been documented. This paper provides a definition of the knee point which can be used as a degradation metric, and develops an algorithm to identify it. The algorithm is implemented on various data cases, and the results indicate that the approach provides repeatable knee point identification.
1 March 2016 in Mechanical Systems and Signal Processing
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Journal Article
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JHJong Moon Ha
Jong Moon Ha
BYByeng D. Youn
Byeng D. Youn
HOHyunseok Oh
Hyunseok Oh
BHBongtae Han
Bongtae Han
YJYoongho Jung
Yoongho Jung
JPJungho Park
Jungho Park
3 September 2004 in IEEE Transactions on Components and Packaging Technologies
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Journal Article
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ESE. Stellrecht
E. Stellrecht
BHBongtae Han
Bongtae Han
Michael Gerard PechtMichael Gerard Pecht
Michael Gerard Pecht
Hygroscopic swelling behavior of mold compounds is analyzed by a novel experimental procedure using a whole-field displacement technique. Large variation in moisture content at the virtual equilibrium state is observed, while the coefficient of hygroscopic swelling is shown to not vary significantly. An investigation on an actual package is also performed to determine the hygroscopic swelling mismatch strains at the chip/mold compound interface. The results are compared with the thermal expansion mismatch strains at the same interface and reveal much higher hygroscopic swelling mismatch strains. The hygroscopic strains must be considered for reliability assessment when a package is subjected to environments where the relative humidity fluctuates.
1 September 1995 in Journal of Electronic Packaging
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Journal Article
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PDF file
BHBongtae Han
Bongtae Han
YGY. Guo
Y. Guo
Thermo-mechanical behavior of various levels of electronic packaging products is studied by moire´ and microscopic moire´ interferometry. The global deformations of packages with complex geometries and the local deformations of solder interconnections are determined by displacement measurements of high sensitivity and high spatial resolution. Several packaging studies are reviewed. They include analyses of thin small outline package, leadless chip carrier package, surface mount array package, chip/organic carrier package, deformation near a plated through hole, and determination of an effective CTE. In-situ and quantitative nature of the methods leads to more accurate and realistic understanding of the macro and micro mechanical behavior of packaging assemblies and interconnections, which in turn, facilitates design evaluation and optimization at an early stage of product development.