2/6/16

You are invited to attend a lecture

By:

 

Mr. Greg Kaplan

M.Sc. student of

Professor Jacob Scheuer of Electrical Engineering, Physical Electronics Department Tel Aviv University

Dynamically Controlled Plasmonic Nano-Antennas

Plasmonic nano-antennas at optical frequencies have been the focus of numerous studies during the last decade, resulting in applications ranging from spectroscopy and near-field microscopy to non-linear optics, holography, sensing and many others. Dynamically controlling the resonance frequency or the phase response of a nanoantenna is highly desirable, both for post-fabrication tuning and to enable novel applications such as an optical phased array. The latter concept facilitates beam steering and shaping without mechanical motion, and is therefore much sought after, with possible applications including laser steering for free-space optical communication, LIDARs, dynamic holographic displays and chip-scale photonic devices.

In the first part of the talk a reflective nano-antenna array utilizing vanadium dioxide (VO2) as a means of continuous electrical steering of an incident IR beam will be proposed and analyzed. VO2 is a phase-change material, which exhibits a phase transition around 67°C, accompanied by a large shift in its refractive index. The proposed device is a 1D finite array of slots in a gold film deposited over a layer of VO2, supported by an alumina substrate. For the presented configuration we find that the phase response can be tuned over a range of 2.2 rad, yielding a steering angle of up to   from the normal, with a temperature gradient of less than 10°C across the array.

In the second part, experimental verification studies are presented, and future research directions are discussed.

 

Thursday, June 02, 2016, at 9:00

Room 011, Kitot Building

02 ביוני 2016, 9:00 
011 Kitot  
2/6/16

 

Material Sciences and Engineering: Departmental Seminar

Tissue engineering on the nanoscale

Dr.  Tal Dvir

Head, Laboratory for Tissue Engineering and Regenerative Medicine.

Department of Molecular Microbiology & Biotechnology,

Department of Materials Science and Engineering,

The Center for Nanoscience and Nanotechnology. Tel Aviv University

01 ביוני 2016, 16:00 
Room 103, Engineering Class (Kitot) Building  
Material Sciences and Engineering: Departmental Seminar

 

תערוכת פוסטרים - בית הספר להנדסה מכנית

24 במאי 2016, 13:30 
 
תערוכת פוסטרים - בית הספר להנדסה מכנית

הזמנה לתערוכת הפוסטרים, של בית הספר להנדסה מכנית, שתתקיים ביום ג' 24.5.16, במסדרון המקורה שבחזית בניין מעבדות. התערוכה היא בין השעות 10.00 ל- 13.00.

ניתן יהיה להתרשם מהעבודה ההנדסית שבוצעה, במסגרת פרויקטי הגמר.

בנוסף לפוסטרים יוצגו דגמים שנבנו, בחלק מהפרויקטים וכן סימולציות פעולה במחשב.

 

סמינר מחלקתי - ניר אופק

Granular Opinion Mining from User-Generated Content

14 ביוני 2016, 14:00 
בניין וולפסון חדר 206  

Abstract

The unprecedented popularity and evolution of communication platforms has led to an 

abundance of user-generated content across the Web. Mining and aggregating this information 

across opinion-rich resources help to address important questions and provide organizations with 

information vital for decision making. Opinion mining—the computational detection and study 

of opinions and viewpoints underlying a text span—enables organizations to provide significant 

insight into opinions without having to directly survey populations, a time-consuming and 

expensive task. However, opinion mining is considered a challenging task because text, despite 

being perfectly suitable for human consumption, is largely unintelligible for machines, 

particularly so for short user-generated content. This talk will highlight the challenge of opinion 

mining in short text spans, and suggest novel statistical and machine learning methods we 

developed in addressing these challenges. Additionally, it will discuss how such methods help 

organizations to identify issues that bother their users.

 

Bio

Nir Ofek wrote his PhD on granular opinion mining at the Department of Information System Engineering, Ben-

Gurion University, Israel under the supervision of Lior Rokach. He received there his M.Sc. and B.Sc. degrees 

under the accelerated M.Sc. program for outstanding students, specializing in AI search. His research focuses 

on machine learning in mining sequential data.

22/5/16

You are invited to attend a lecture

By

 

NANO-ANTENNA ARRAY CHARACTERIZATION, DESIGN, AND APPLICATIONS

Zeev Iluz

Ph.D. student of

Professor Amir Boag of Electrical Engineering, Physical Electronics Department Tel Aviv University

 

At radio frequencies (RF), antenna array active impedance is conventionally determined via direct S-parameter measurements. This approach is impossible to implement for optical nano-antenna arrays. The first part of this work describes a technique for evaluating antenna array active impedance based on scattering fields’ measurements, using different loads at the antenna’s terminal. This technique can also be used for optical sensor applications, since the scattering data of a nano-antenna array, loaded with unknown loads, can be used to determine the reflection coefficient of the loads. The theoretical formulation, followed by simulations and measurements demonstrate the advantages of this technique. The suggested measurement technique was fully validated in the RF band, including measurements of unknown load.

The second part of this work involved the design of a new, wideband and an efficient nanoantenna array in optics. A Dual-Vivaldi nanoantenna is proposed to demonstrate the possibility of wideband operation at IR and visible frequencies. The Dual-Vivaldi nanoantenna arrays were designed, fabricated, and optically characterized. The radiation efficiency and the spectral response of the antennas were found to be in good agreement with numerical simulations. The results presented here demonstrate the extremely wideband nature of the antenna and the strong impact of load at the antenna’s terminals on its scattering response.

The last part of this work focused on the application aspect, meaning taking “old” ideas from the RF and implementing/transforming them in the optical frequency range.  In many cases, this transformation cannot be done in a straightforward way, and the proper adjustment or a complete new concept is required for an efficient device.

The optical devices developed in this work include a new refractive index sensor which is based on the antenna array scan blindness. While in RF the scan blindness is avoided, in optics it is used to enhance the sensor performance. The second device is an optical reflectarray with high efficiency due to the concept of multi-elements in the unit cell. The multi-elements concept generates several phase / losses vs. dimensions curves, which

 

 

enables the option to minimize the losses for a desired phase value. The third device is optical phased array with wide scan angle capability. A new geometry, consisting of dielectric waveguide coupled to a nanoantenna patch, is presented. This structure supports small array spacing and therefore a wide angle scan.

 

Sunday, May 22, 2016, at 12:00

Room 011, Kitot Building

 

22 במאי 2016, 12:00 
011 Kitot  
22/5/16

 

טקס חלוקת תארים - הפקולטה להנדסה

31 במאי 2016, 19:30 
אודיטורים סמולארש  
טקס חלוקת תארים - הפקולטה להנדסה

הטקס של הפקולטה להנדסת חשמל יתקיים ב-31.5.16,

 

טקס חלוקת תארים - הנדסת חשמל

30 במאי 2016, 19:30 
אודיטורים סמולארש  
טקס חלוקת תארים - הנדסת חשמל

הטקס של ביה"ס להנדסת חשמל יתקיים ב-30.5.16,

 

EE Seminar: Design of a Decoupled Branch Predictor for a Deeply Pipelined Embedded VLIW DSP

~~
Speaker: Konstantin Berestizshevsky,
M.Sc. student under the supervision of Prof. Shlomo Weiss

Wednesday, May 25, 2016 at 15:00
Room 011, Kitot Bldg., Faculty of Engineering

Design of a Decoupled Branch Predictor for a Deeply Pipelined Embedded VLIW DSP
Abstract
One of the classical problems in the world of computer architecture is the ``branch prediction'' problem, also known as the "control hazard". This problem occurs whenever a pipelined processor fetches a branch instruction, making it unclear which instruction to fetch next. Waiting until the resolution of the branch in the deeper pipeline stages will cost several clock cycles, and hence an immediate branch-prediction should be made. Numerous DSP designs that relied on static (non-hardware) solutions of the branch-prediction problem began gradually loosing performance as their pipelines deepened, causing the penalties of branch mis-prediction to become unbearable.

This work presents a design of a dynamic branch predictor. The proposed design, called decoupled-predictor, literally decouples the prediction making from the prediction update stages of the scheme. This separation follows the basic rule of "divide and conquer", making it possible to tailor each part for its particular task. Moreover, such an approach leads the way to a successful micro-architectural planning, since the prediction and the update stages are naturally decoupled in the microprocessor's pipeline. In this thesis we combine the opportunity of developing a new branch prediction approach, with the opportunity of incorporating a dynamic branch prediction into a DSP core that formerly relied on a static prediction. This thesis presents a detailed description of the predictor architecture and evaluates its performance through a set of trace driven simulations. Finally, we address the cost efficiency of the design by offering memory saving optimizations.

25 במאי 2016, 15:00 
חדר 011, בניין כיתות-חשמל  

עמודים

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