הפקולטה להנדסה ע"ש איבי ואלדר פליישמן

סמינר מחלקתי Prof. Arkady Tsinober

23 בדצמבר 2015, 15:00

School of Mechanical Engineering Seminar
Monday, December 23, 2015 at 15:00
Wolfson Building of Mechanical Engineering, Room 206

Paradigmatic issues in turbulence problem/phenomenon*

Prof. Arkady Tsinober

School of Mechanical Engineering, Tel Aviv University

General and Introductory notes

The general/primary premises and the reasons/causes of this talk are the absence of theory based on first principles and inadequate tools to handle both the problem and the phenomenon of turbulence, Kolmogorov, von Neumann, for references on the issue see [1, ch 9], [2, ch 11]. Among the consequences is that turbulence research is loaded with misconceptions and ill defined concepts, outdated “paradigms”, multitude of problematic analogies and alike - quite a bit of what is called “understanding” in turbulence, etc. There is still a massive belief in most of these traveling from one publication to another and exhibited in a pretty articulate fashion in crowded meetings.

Examples of most popular outdated "paradigms" - in brief

• Turbulence is an essentially inviscid, inertial phenomenon and is uninfluenced by the precise nature of the viscous mechanism;

Cascade, locality versus nonlocality, inertial range and scale invariance, utility (and futility) of decompositions.

• Vorticity amplification is a result of the kinematics of turbulence, i.e. vortex lines are on average stretched rather than compressed, because two particles on average move apart from each other.

Explicit example(s) - in more detail

• Rather than "essentially inviscid" turbulence is an essentially strongly dissipative (lots of dissipation) and rotational (plenty of vorticity) phenomenon; the "guilty" processes for these properties. Are these processes well understood as massively claimed?

Concluding remarks on the present state of matters as long-lasting and continuing paradigmatic crisis...

References [1] A. Tsinober 2009 An informal Conceptual Introduction to Turbulence, Springer Verlag. [2] A. Tsinober, 2013/4 The Essence of Turbulence as a Physical Phenomenon with Emphasis on Issues of paradigmatic nature, Springer Verlag.

סמינר מחלקתי Tal Cohen

09 בדצמבר 2015, 15:00

וולפסון 206

School of Mechanical Engineering Seminar
Wednesday, December 9, 2015 at 15:00
Wolfson Building of Mechanical Engineering, Room 206

Mechanics of Squishy Materials

Tal Cohen

Department of Mechanical Engineering, MIT

School of Engineering and Applied Sciences, Harvard

Following a short overview of my previous work on shock wave propagation and dynamic cavitation in porous plasticity, in this seminar I will focus on some fundamental problems in the nonlinear mechanics of soft and biological materials; (i) the geometrically unique phenomenon of elastic fingering, a rate-independent instability observed at large strains, (ii) the ubiquitous phenomenon of creasing, which in recent years has been indicated as a distinct mode of instability from wrinkling, and (iii) the effect of viscoelasticity in dynamic cavitation. I will show how the theoretical models are able to capture the essential features of these phenomena, in comparison with numerical simulations and experimental observations, and will discuss some ongoing efforts to apply the models experimentally to measure the material properties of biological tissue.

Bio

Tal Cohen is currently finishing at two year postdoc period at the Department of Mechanical Engineering at MIT, under the supervision of Prof. Rohan Abeyaratne, and starting a second postdoc position at the School of Engineering and Applied Sciences at Harvard. There she is working under the joint mentoring of Professors Katia Bertoldi and L. Mahadevan. She received both her MSc and PhD at the Faculty of Aerospace Engineering at the Technion in Israel under the supervision of Prof. David Durban. Her research is broadly aimed at understanding the nonlinear mechanical behavior and constitutive sensitivity of solids through analytical investigation. This includes behavior under extreme loading conditions, involving propagation of shock waves and dynamic cavitation, material instabilities and growth.

EE Seminar: On the Construction of Polar Codes for Channels with Moderate Input Alphabet Sizes

~~ (The talk will be given in English)

Speaker: Dr. Ido Tal
EE, Technion

Monday, December 7th, 2015
15:00 - 16:00
Room 011, Kitot Bldg., Faculty of Engineering
On the Construction of Polar Codes for Channels with Moderate Input Alphabet Sizes
Abstract
Current deterministic algorithms for the construction of polar codes can only be argued to be practical for channels with small input alphabet sizes. We show that any construction algorithm for channels with moderate input alphabet size which follows the paradigm of ``degrading after each polarization step'' will inherently be impractical with respect to a certain ``hard'' underlying channel. This result also sheds light on why the construction of LDPC codes using density evolution is impractical for channels with moderate sized input alphabets.
Bio
Ido Tal obtained his B.Sc., M.Sc., and Ph.D. from the Computer Science department at Technion. After completing his Ph.D. he was a postdoctoral scholar at the University of California at San Diego. He is currently an assistant professor at the electrical engineering department at Technion

07 בדצמבר 2015, 15:00

חדר 011, בניין כיתות-חשמל

24 נובמבר 2015

ידיעות נוספות בנושא

EE SEminar: Blind Image Deblurring Via Residual Blur Elimination

~~Speaker: Rana Hanocka,
M.Sc. student under the supervision of Prof. Nahum Kiryati

Wednesday, December 16th, 2015 at 15:30
Room 011, Kitot Bldg., Faculty of Engineering

Blind Image Deblurring Via Residual Blur Elimination

Abstract

We present a novel progressive framework for blind image restoration. Common blind restoration schemes first estimate the blur kernel, then employ non-blind deblurring. However, despite recent progress, the accuracy of PSF estimation is limited. Furthermore, the outcome of non-blind deblurring is highly sensitive to errors in the assumed PSF. Therefore, high quality blind deblurring has remained a major challenge. We suggest an iterative progressive restoration scheme, in which the imperfectly deblurred output of the current iteration is fed back as input to the next iteration. The kernel representing the residual blur is then estimated, and used to drive the non-blind restoration component, leading to finer deblurring. Our framework is extremely modular. Our proposed method is able to adapt to various kernel estimation and non-blind deblurring modules, including state-of-the-art art regularizers for the image and the PSF. A particularly interesting combination is the Mumford & Shah piecewise-smooth image model and the sparse PSF prior. Previous works that used Mumford & Shah image regularization were either limited to non-blind deblurring or semi-blind deblurring assuming a parametric kernel known up to an unknown parameter. Experimental results demonstrate rapid convergence, and excellent performance on a wide variety of blurred images.

16 בדצמבר 2015, 15:30

חדר 011, בניין מעבדות חשמל

24 נובמבר 2015

לעבר אבחנת ודירוג תאים סרטניים מבדיקת דם פשוטה:

אחד האתגרים הגדולים בתחום של דימות אופטי של תאים חיים הוא להשיג מדידות של התאים ללא סימון אך בצורה כמותית, כך שיתאפשר מיפוי מבני ומכני ברזולוציה גבוהה ברמה התאית. כמקרה פרטי, פיתוח טכנולוגיות דימות אופטיות יעילות ולא סובייקטיביות עבור אבחנת סרטן ברמה התאית היא משימה קשה ומאתגרת. בפרויקט זה, נפתח כלים לצורך אבחון וניטור של תאי סרטן מחוץ לגוף והפוטנציאל המטסטטי שלהם. אינטרפרומטריה אופטית יכולה לדמות תאים חיים בצורה כמותית ללא השפעות שליליות שעלולות להיגרם כתוצאה מהשימוש בסמנים חיצוניים. על ידי פתרון של מחסומים טכנולוגיים קריטיים, אנו מציעים גישות היברידיות לאינטרפרומטריה אופטית שמספקות כלים רבי עוצמה לננו-חישה של תאי סרטן, ללא צורך בסימון ובצורה כמותית. זאת נבצע על ידי הקלטה של המבנה התת ננו-מטרי והמכני של תאי סרטן חיים בשלביהם השונים. למטרה זו, נפתח מערכת אינטרפורמטרית אופטית חדשנית, בעלת רמת רעש נמוכה, המוארת במקור רחב סרט. המערכת תהיה מסוגלת להקליט את התאים בדיוק תת ננו-מטרי ובמהירות של אלפי תמונות לשניה. בנוסף, נפתח גישה חדשה לטומוגרפיה אופטית של תאי סרטן חיים בתרחיף (תאים שלא קשורים למשטח), לשם לכידת המפה התלת-ממדית של מקדם השבירה שלהם, ככלי לניטור של התקדמות של הסרטן בתא. לשם כך, נשלב אינטרפרומטריה אופטית עם שיטות למיקרו-מניפולציה של תאים בודדים, מה שיאפשר סיבוב מלא של התא, וטומוגרפיה של תאים שאינם קשורים למשטח, כמו גם וידוא של המדידות המכניות בתאים. בנוסף, נפתח סט חדש של פרמטרים כמותיים המבוסס על המדידות האינטרפרומטריות שיאפשר אפיון של טרנספורמציות תאיות, כולל אפיון של תאי סרטן עם פוטנציאלים מטסטטיים שונים. הדבר יעשה בהתחלה על שורות תאים, ואז על תאי סרטן המטיילים בדם, שאותם נבודד מדגימות דם.

3-D refractive index map of yeast cells obtained by the proposed TPM-HOTs technique.

ידיעות נוספות בנושא

24 נובמבר 2015

24 נובמבר 2015

ידיעות נוספות בנושא

23 נובמבר 2015

ידיעות נוספות בנושא

סמינר מחלקתי - ליאור תורג'מן

A Mixed-ensemble Predictive Model for Hospital Readmission

29 בדצמבר 2015, 14:00

וולפסון 206

Abstract:

In this talk, I will present a novel approach for predictive modeling, using a mixed-ensemble classifier. The approach integrates a C5.0 tree as the base ensemble classifier, and a support vector machine (SVM) as a secondary classifier. The tree base classifier enables exploratory knowledge discovery about the learned database. The flexibility of the secondary SVM algorithm, in terms of controlling the width of the margins around the separating hyperplane, and in terms of classification error, allows for a controlled-sensitive classification of the minority class. By implementing our method for predicting hospital readmission of Congestive Heart Failure (CHF) patients in the Veterans Health Administration (VHA) hospital system of Pittsburgh, we were able to overcome some of the limitations of both C5.0 and SVM, as well as to increase the classification accuracy for the minority class, particularly when strong predictors are not available. I will also present a new approach of identification of readmission risk factors during the hospitalization process, by fitting a Coxian phase-type distribution to their length of stay (LOS) data, and analyzing the strength of the connections among patient characteristics within each extracted state in the latent Markov process. Some possible research directions of applying the suggested methods for other fields of application-driven research will be also presented.

Bio :

Lior Turgeman is a postdoctoral researcher at the Joseph M. Katz Business School, University of Pittsburgh, where he has been since 2014. Lior completed his Ph.D in Engineering at Bar-Ilan University on 2013. His research interests lie in the area of stochastic modeling, systems engineering, data mining and predictive analytics, ranging from theory to design to implementation, with a focus on application-driven systems. In recent years, he has focused on developing better techniques of data analysis, and optimization, of healthcare and biomedical measurement systems, particularly in case where only partial knowledge of their state is given. He has collaborated actively with researchers in several other disciplines of medicine, industrial engineering, and computer science, as well as with the Pittsburgh Veterans Engineering Resource Center (VERC).

סמינר מחלקתי Prof. Arkady Tsinober

סמינר מחלקתי Tal Cohen

EE Seminar: On the Construction of Polar Codes for Channels with Moderate Input Alphabet Sizes

2016 IEEE Dennis J. Picard Medal for Radar Technologies and Applications

ידיעות נוספות בנושא

EE SEminar: Blind Image Deblurring Via Residual Blur Elimination

מחקר של דר' נתי שקד

ידיעות נוספות בנושא

התכנית החדשה לפיתוח טכנולוגיות רפואיות פורצות דרך

בשביל הסטרימינג המהיר: ColorChip הישראלית גייסה 25 מיליון דולר

ידיעות נוספות בנושא

24 בפברואר 2016, ט”ו אדר א’ התשע”ו, מרכז הקונגרסים הבינלאומי בחיפה

ידיעות נוספות בנושא

סמינר מחלקתי - ליאור תורג'מן

עמודים