520 research outputs found
Investigation of Potential Resonances in CEMPIE-PEEC Simulations of Multilayered PCBs
No full textAccurate simulation of printed circuit boards (PCBs) with
power bus is of concern to EMC engineers. Recently the
new circuit rxtraction tool CEMPIE-PEEC has proved to
be a robust method for full-wave numerical modeling of
printed structures. Nevertheless snme sharp odd resonances
have been observed in the simulation of some structures.
This paper tries to give insights into the reasons of
these singularities through comparisons of the CEMPIEPEEC
results with integral - MOM - and differential -
FDTD ~ full-wave methods
Extraction of a SPICE via model from full-wave modeling for differential signaling
No full textThe paper presents a procedure for building SPICE models for via transitions in differential signaling. The method of extracting parameters of SPICE models from a full-wave simulation tool is demonstrated. Then the validity of the SPICE models is studied by comparing the solution from the SPICE models with that from the full-wave simulation
SPICE model libraries for via transitions
No full textA procedure of building SPICE models for signal via transitions between printed circuit board layers is presented in this paper. The method of extracting parameters of SPICE models from full-wave simulation tool is demonstrated. Then the validity of SPICE models is studied by comparing the solution from SPICE model with that from the full-wav
Validation of equivalent circuits extracted from S-parameter data for eye-pattern evaluation
No full textS-parameter circuit model extraction is usually characterized by a trade off between accuracy and complexity. Trading one feature for another may or may not affect the goodness of the reconstructed S-parameter data, which are obtained from frequency domain simulations of the models extracted. However, the ultimate test for the validity of these equivalent circuit representations should be left to eye-diagram simulations, which provide useful insights, from an SI point of view, about the degradation of the signal, as it travels through the system. Physics based simplification procedures can be used to tune the models and achieve less complexity, whereas the comparisons of the eye-diagrams may help to quantify the goodness of all these circuits extracted. In fact, the most accurate model is not necessary the best to be use
Engineering a Culture of Public Engagement in the Trump Era—Challenging the Status Quo
No full textOn May 25th, 2020, George Floyd’s death sparked an international outrage that embroils all extremes of the political, ethical, legal, and historical discourse on racist policing practices. Yet, there are STEM professionals who refrain from public and political discussions simply because they believe that these discussions are irrelevant to their professions. The purpose of this article is to call on those who have remained silent to speak out in support of the Black Lives Matter, specifically those scientific and engineering professionals who practice the “culture of disengagement” from politics and public discourse, for silence equates complicity when it comes to racism.This article is published as Nguyen, Luan. "Engineering a Culture of Public Engagement in the Trump Era—Challenging the Status Quo." International Journal of Engineering, Social Justice, and Peace 8, no. 1 (2021): 84-91. DOI: 10.24908/ijesjp.v8i1.14211. Copyright 2021 The Author. Attribution 3.0 Unported (CC BY 3.0). Posted with permission
I watch the boughs
No full textA manuscript of poems by Emily LuanM.F.A.Includes bibliographical reference
CAD model extraction of PCB signal discontinuity using a circuit extraction approach based on mixed-potential integral equation formulation
No full textIn high-speed digital design, signal via transitions on printed circuit boards (PCBs) are becoming an important signal integrity issue. Efficient and accurate models for via transitions are necessary to analyze high bit-rate digital circuit system. The circuit extraction approach based on a mixed-potential integral equation formulation (CEMPIE) is an extension of the Partial Element Equivalent Circuit approach (PEEC) to general multi-layered media. CEMPIE was further developed to include the horizontal current components on the vertical surface and extended to model the discontinuities on multilayer PCBs. A procedure of building SPICE models for signal via transitions between printed circuit board layers was developed. The method of extracting SPICE model parameters from full-wave simulation tool was studied. The validity of SPICE models was studied by comparing solutions from SPICE models with solutions from full-wave simulations. This procedure was further used for building SPICE models for via transitions in differential signaling --Abstract, page iii
Luan shi jia ren.
No full text王光鼐編劇.據美國密西爾的《飄》改編.Play.Wang Guangnai bian ju.Ju Meiguo Mixier de "Piao" gai bian
Alternative design optimization formulations – developing and comparing for a vibration damping example
No full textDeveloping mathematical formulations for design problems requires determining an objective function to compare design alternatives, a set of design features and options to be included for consideration, and a predictive model that reflect any unavoidable cause and effect relationships that are relevant. There are no formal principles guiding the formulation process, and heuristics prevail. There are some instances when the level of effort required to formulate the problem and solve the problem are excessive, not worth the improvement that might be realized in the overall design objective. In other words, a hypothetically “perfect” design problem formulation that takes all possible factors into account might be so difficult to fully compose and solve that it is not worth the effort. This thesis presents a set of guidelines for formulating design problems that seeks a middle ground. The method presented defines three different tasks in the formulation process: comparison metrics, predictive model and design representation. Each task offers opportunities for the practitioner to balance the expected quality of the solution with the level of effort and time required to reach that solution. This thesis demonstrates how using the guidelines can help create alternative formulations for the same design problem, and then how the resulting solutions can be evaluated and compared. Using a vibration absorber design example, the guidelines are enumerated, explained, and used to compose six alternative optimization formulations of the problem. These alternatives formulations vary in objective functions, decision variables, and some other design formulation practices. The overall goal is to maximize surface finish quality of a machined component processed on a platform to which the vibration absorber is attached. Vibrations of the platform can have a detrimental effect on surface quality. The goal of the vibration absorber system is to minimize these detrimental effects. The six alternative optimization formulations are subsequently solved, and their scores reflecting their complexity, computational time and solution quality are quantified and compared. The results illustrate the unavoidable tradeoffs among these three attributes. The best formulation depends on the set of tradeoffs that are best in that situation, given the decision maker’s risk attitude and preference.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-08-01The student, Siyao Luan, accepted the attached license on 2017-07-20 at 13:50.The student, Siyao Luan, submitted this Thesis for approval on 2017-07-20 at 13:54.This Thesis was approved for publication on 2017-07-20 at 14:59.DSpace SAF Submission Ingestion Package generated from Vireo submission #11555 on 2017-09-29 at 11:19:58Made available in DSpace on 2017-09-29T17:52:30Z (GMT). No. of bitstreams: 2
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Previous issue date: 2017-07-20Embargo set by: Colleen Fallaw for item 103514
Lift date: 2019-09-29T17:52:45Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 103514 on 2019-09-30T09:15:29Z
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