Magnetic Current Imaging Techniques: Comparative Case Studies

2004 ◽  
Author(s):  
Olivier Crépel ◽  
Philippe Descamps ◽  
Patrick Poirier ◽  
Romain Desplats ◽  
Philippe Perdu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Integrated Circuits ◽  
Case Studies ◽  
Flip Chip ◽  
Imaging Techniques ◽  
Optimal Domain ◽  
Magnetic Current ◽  
Comparative Case Studies ◽  
Current Flows

Abstract Magnetic field based techniques have shown great capabilities for investigation of current flows in integrated circuits (ICs). After reviewing the performances of SQUID, GMR (hard disk head technologies) and MTJ existing sensors, we will present results obtained on various case studies. This comparison will show the benefit of each approach according to each case study (packaged devices, flip-chip circuits, …). Finally we will discuss on the obtained results to classify current techniques, optimal domain of applications and advantages.

scholarly journals Vector Magnetic Current Imaging of an 8 nm Process Node Chip and 3D Current Distributions Using the Quantum Diamond Microscope

2021 ◽  
Author(s):  
Sean M. Oliver ◽  
Dmitro J. Martynowych ◽  
Matthew J. Turne ◽  
David A. Hopper ◽  
Ronald L. Walswort ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Failure Analysis ◽  
Flip Chip ◽  
Circuit Board ◽  
Depth Information ◽  
Magnetic Current ◽  
Current Distributions ◽  
Process Node ◽  
The Magnetic Field

Abstract The increasing trend for industry adoption of three-dimensional (3D) microelectronics packaging necessitates the development of new and innovative approaches to failure analysis. To that end, our team is developing a tool called the quantum diamond microscope (QDM) that leverages an ensemble of nitrogenvacancy (NV) centers in diamond for simultaneous wide fieldof- view, high spatial resolution, vector magnetic field imaging of microelectronics under ambient conditions [1,2]. Here, we present QDM measurements of two-dimensional (2D) current distributions in an 8 nm process node flip chip integrated circuit (IC) and 3D current distributions in a custom, multi-layer printed circuit board (PCB). Magnetic field emanations from the C4 bumps in the flip chip dominate the QDM measurements, but these prove to be useful for image registration and can be subtracted to resolve adjacent current traces on the micron scale in the die. Vias, an important component in 3D ICs, display only Bx and By magnetic fields due to their vertical orientation, which are challenging to detect with magnetometers that traditionally only measure the Bz component of the magnetic field (orthogonal to the IC surface). Using the multi-layer PCB, we demonstrate that the QDM's ability to simultaneously measure Bx, By, and Bz magnetic field components in 3D structures is advantageous for resolving magnetic fields from vias as current passes between layers. The height difference between two conducting layers is determined by the magnetic field images and agrees with the PCB design specifications. In our initial steps to provide further z depth information for current sources in complex 3D circuits using the QDM, we demonstrate that, due to the linear properties of Maxwell's equations, magnetic field images of individual layers can be subtracted from the magnetic field image of the total structure. This allows for isolation of signal from individual layers in the device that can be used to map embedded current paths via solution of the 2D magnetic inverse. Such an approach suggests an iterative analysis protocol that utilizes neural networks trained with images containing various classes of current sources, standoff distances, and noise integrated with prior information of ICs to subtract current sources layer by layer and provide z depth information. This initial study demonstrates the usefulness of the QDM for failure analysis and points to technical advances of this technique to come.

scholarly journals Multi-instrument observations of nightside plasma patches under conditions of IMF <I>B<sub>z</sub></I> positive

2008 ◽  
Vol 26 (8) ◽  
pp. 2203-2216 ◽  
Author(s):  
A. G. Wood ◽  
S. E. Pryse ◽  
H. R. Middleton ◽  
V. S. C. Howells
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Case Studies ◽  
Significant Role ◽  
Convective Flow ◽  
Magnetic Sector ◽  
Plasma Drift ◽  
First Case ◽  
Eiscat Radar

Abstract. Results are presented from two multi-instrument case studies showing patches of cold, long-lived plasma in the winter nightside ionosphere during times when the z-component of the Interplanetary Magnetic Field (IMF Bz) was positive. These enhancements were coincident with the antisunward convective plasma drift, flowing from polar to nightside auroral latitudes. In the first case, on 5 December 2005 with IMF By negative, two regions of enhanced electron density were observed extended in MLT in the magnetic midnight sector separated by lower densities near midnight. It is likely that the earlier enhancement originated on the dayside near magnetic noon and was transported to the nightside sector in the convective flow, whilst the later feature originated in the morning magnetic sector. The lower densities separating the two enhancements were a consequence of a pair of lobe cells essentially blocking the direct antisunward cross polar flow from the dayside. A second case study on 4 February 2006 with IMF By positive revealed a single nightside enhancement likely to have originated in the morning magnetic sector. These multi-instrument investigations, incorporating observations by the EISCAT radar facility, the SuperDARN network and radio tomography, reveal that plasma flowing from the dayside can play a significant role in the nightside ionosphere under conditions of IMF Bz positive. The observations are reinforced by simulations of flux-tube transport and plasma decay.

Rational Deterrence Theory and Comparative Case Studies

1989 ◽  
Vol 41 (2) ◽  
pp. 143-169 ◽  
Author(s):  
Christopher H. Achen ◽  
Duncan Snidal
Keyword(s):  
Case Studies ◽  
Prior Knowledge ◽  
Statistical Tests ◽  
Theory Building ◽  
Deterrence Theory ◽  
Middle Range ◽  
Comparative Case Studies ◽  
Empirical Generalizations ◽  
Tests Of Hypotheses

Several recent books have argued that comparative case studies of crises demonstrate the failure of rational-deterrence theory; they have offered certain empirical generalizations as substitutes. This paper shows that such contentions are unwarranted. First, the empirical generalizations are impressive as historical insights, but they do not meet the standards for theory set out by the most sophisticated case-study analysts themselves. Second, the “tests” of rational deterrence used in the case studies violate standard principles of inference, and the ensuing procedures are so biased as to be useless. Rational deterrence, then, is a more successful theory than portrayed in this literature, and it remains the only intellectually powerful alternative available.Case studies are essential to theory building: more efficiently than any other methods, they find suitable variables, suggest middle-range generalizations for theory to explain, and provide the prior knowledge that statistical tests require. Their loose constraints on admissible propositions and suitable evidence are appropriate and even necessary for these tasks. These same characteristics, however, inevitably undermine all attempts to construe case-study generalizations as bodies of theory or tests of hypotheses.

scholarly journals Comparative case studies on ring gear fault diagnosis of planetary gearboxes using vibrations and acoustic emissions

2021 ◽  
Author(s):  
Félix Leaman ◽  
Ralph Baltes ◽  
Elisabeth Clausen
Keyword(s):  
Fault Diagnosis ◽  
Wind Turbine ◽  
Case Studies ◽  
Vibration Analysis ◽  
Acoustic Emissions ◽  
Wind Turbine Gearbox ◽  
Planetary Gearbox ◽  
Vibration Sensors ◽  
Comparative Case Studies

AbstractThe analysis of vibrations and acoustic emissions (AE) are two recognized non-destructive techniques used for machine fault diagnosis. In recent years, the two techniques have been comparatively evaluated by different researchers with experimental tests. Several evaluations have shown that the AE analysis has a higher potential than the vibration analysis for fault diagnosis of mechanical components for certain cases. However, the distance between the AE sensor and the fault is an important factor that can considerably decrease the potential to detect damage and that has not been sufficiently investigated. Moreover, the comparisons have not yet addressed conditions of slow speed that for example are usual for wind turbine gearboxes. Therefore, in this paper we present two comparative case studies that address both topics. Both case studies consider planetary gearboxes with faults in their ring gears. The first case study corresponds to a small planetary gearbox in which the AE and vibration sensors were installed together at two different positions. The second case study corresponds to a full-size wind turbine gearbox in which three pairs of AE and vibration sensors were installed on the outside of the ring gear from a low-speed planetary stage. The results of the evaluations demonstrate the important influence of the distance between sensors and fault. Despite this, the good results from the AE analysis indicate that this technique should be considered as an important complement to the traditional vibration analysis. The main contribution of this paper is comparing AE and vibration analysis by using not only experimental data from a small planetary gearbox but also from a full-size wind turbine gearbox. The comparison addresses the topics of proximity of the sensor to the fault and low-speed conditions.

Natural locations and the distinction between ‘what’ and ‘where’ concepts: Evidence from differential locative marking in Makalero

Linguistics ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 477-512 ◽  
Author(s):  
Juliette Huber
Keyword(s):  
Internal Structure ◽  
Case Studies ◽  
Spatial Relations ◽  
East Timor ◽  
The World ◽  
Comparative Case Studies ◽  
Specific Construction

Abstract Differential locative marking is found in languages all over the world. Toponyms, in particular, are well known to often require less locative marking than other types of nouns, and it has been suggested that they express ‘where’ concepts. This paper presents a case study of differential locative marking in Makalero, a Papuan language of East Timor, where nouns fall into three categories: those which need no overt locative marking, i.e., can be zero-marked; those which are used with a semantically general locative verb; and those which can only be used with semantically specific locative verbs. Zero-marking of spatial relations occurs only in a specific construction where the nouns in question are used predicatively, suggesting that the syntactic equivalent of the ‘where’ category is a relational expression, not a noun. There is furthermore a certain degree of flexibility in Makalero locative constructions, and alternative expressions result in predictable semantic differences. These differences show that the lack of perceptual boundaries and of an internal structure are important parameters that distinguish the referents of so-called natural location nouns from nouns which denote ‘what’ concepts. More comparative case studies are needed to enrich our understanding of these notions and the properties characterizing them.

Behind the Veil of the Old

2021 ◽  
pp. 144-170
Author(s):  
Yigal Bronner
Keyword(s):  
Seventeenth Century ◽  
South Asia ◽  
Case Studies ◽  
Intellectual Traditions ◽  
The Will ◽  
Comparative Case Studies ◽  
The Veil

This chapter begins by surveying the petering out of the debate over sequence in interpretation in seventeenth-century India and speculating about the reasons for its decline. At this point, the chapter returns to the broad question of innovation with which this book began, and places the story in the context of the “New Intellectuals” in South Asia and that of a few comparative case studies in order to present a broader survey of modes of novelty in scholastic traditions. The rhetorical stance of traditionalism that masks substantive innovation in the book's main case study has significant parallels in other intellectual traditions, suggesting a larger pattern that may merit further investigation. The “oldness of the will” discussed in chapter 1 may be only a pretense, after all, and a new one at that.

scholarly journals Comparative Case Studies: An Innovative Approach

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Lesley Bartlett ◽  
Frances Vavrus
Keyword(s):  
International Education ◽  
Case Studies ◽  
Case Study Research ◽  
Comparative Case Study ◽  
Study Research ◽  
Comparative And International Education ◽  
Study Approach ◽  
The Social ◽  
Comparative Case Studies

What is a case study and what is it good for? In this article, we argue for a new approach—the comparative case study approach—that attends simultaneously to macro, meso, and micro dimensions of case-based research. The approach engages two logics of comparison: first, the more common compare and contrast; and second, a ‘tracing across’ sites or scales. As we explicate our approach, we also contrast it to traditional case study research. We contend that new approaches are necessitated by conceptual shifts in the social sciences, specifically in relation to culture, context, space, place, and comparison itself. We propose that comparative case studies should attend to three axes: horizontal, vertical, and transversal comparison. We conclude by arguing that this revision has the potential to strengthen and enhance case study research in Comparative and International Education, clarifying the unique contributions of qualitative research.

Between contextuality and comparability: a dilemma in qualitative comparative case studies

2017 ◽  
Author(s):  
Pål Repstad
Keyword(s):  
Social Science ◽  
Case Studies ◽  
International Study ◽  
Case Study Method ◽  
International Group ◽  
Long Run ◽  
Comparative Case Studies ◽  
Conducting Research ◽  
Rich Data

This chapter illustrates the challenge of obtaining notably rich data from the respective localities, while at the same time being able to draw effective and insightful comparisons. Comparative case studies contain an inherent tension between offering a useful and problem-oriented opportunity for conducting research keeping the local situation in mind and seeking more general patterns, which may turn out to be fruitful and rewarding for social science in the long run. The inherent tension in the case study method shows that there is no perfect research design for study in social science. However, when an international group of researchers has been given the means to conduct a large international study and has succeeded in the painstaking job of establishing an international framework, there are some good arguments to develop a design for the study with a minimum level of standardisation, to increase the possibilities of identifying causal mechanisms.

Patientenbezogene Komplexität in der Pflege – Kollektive Case Studies im Akutspital

Pflege ◽  
2018 ◽  
Vol 31 (5) ◽  
pp. 237-244 ◽  
Author(s):  
Caroline Gurtner ◽  
Rebecca Spirig ◽  
Diana Staudacher ◽  
Evelyn Huber
Keyword(s):  
Case Studies ◽  
Study Designs

Zusammenfassung. Hintergrund: Die patientenbezogene Komplexität der Pflege ist durch die Merkmale „Instabilität“, „Unsicherheit“ und „Variabilität“ definiert. Aufgrund der reduzierten Aufenthaltsdauer und der steigenden Zahl chronisch und mehrfach erkrankter Personen erhöht sich die Komplexität der Pflege. Ziel: In dieser Studie untersuchten wir das Phänomen patientenbezogener Komplexität aus Sicht von Pflegefachpersonen und Pflegeexpertinnen im Akutspital. Methode: Im Rahmen eines kollektiven Case-Study-Designs schätzten Pflegefachpersonen und Pflegeexpertinnen die Komplexität von Pflegesituationen mit einem Fragebogen ein. Danach befragten wir sie in Einzelinterviews zu ihrer Einschätzung. Mittels Within-Case-Analyse verdichteten wir die Daten induktiv zu Fallgeschichten. In der Cross-Case-Analyse verglichen wir die Fallgeschichten hinsichtlich deduktiv abgeleiteter Merkmale. Ergebnisse: Die Ausprägung der Komplexität hing in den vier Cases im Wesentlichen davon ab, ob klinische Probleme kontrollierbar und prognostizierbar waren. Je nach individuellen Ressourcen der Patientinnen und Patienten stieg bzw. sank die Komplexität. Schlussfolgerungen: Komplexe Patientensituationen fordern von Pflegefachpersonen Fachwissen, Erfahrung, kommunikative Kompetenzen sowie die Fähigkeit zur Reflexion. Berufsanfänger und Berufsanfängerinnen werden zur Entwicklung dieser Fähigkeiten idealerweise durch erfahrene Berufskolleginnen oder -kollegen unterstützt und beraten.

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