[Research] Detection of MCI using EEG Relative Power + DNNDonghyeon Kim
* This is a summarized presentation material for the conference paper:
Donghyeon Kim, and Kiseon Kim "Detection of Early Stage Alzheimer's Disease using EEG Relative Power with Deep Neural Network," IEEE EMBC 2018
* It was addressed in A-GIST group, study team for Artificial Intelligence in Gwangju Institute of Science and Technology (GIST)
* Youtube (in Korean): https://youtu.be/2maphOXkB6k
Detecting stable phase structures in eeg signals to classify brain activity a...Ehsan Omvi
These patterns are described as stable frames with carrier frequencies in the beta or gamma band that recur at similar rates in the theta or alpha band
[Research] Detection of MCI using EEG Relative Power + DNNDonghyeon Kim
* This is a summarized presentation material for the conference paper:
Donghyeon Kim, and Kiseon Kim "Detection of Early Stage Alzheimer's Disease using EEG Relative Power with Deep Neural Network," IEEE EMBC 2018
* It was addressed in A-GIST group, study team for Artificial Intelligence in Gwangju Institute of Science and Technology (GIST)
* Youtube (in Korean): https://youtu.be/2maphOXkB6k
Detecting stable phase structures in eeg signals to classify brain activity a...Ehsan Omvi
These patterns are described as stable frames with carrier frequencies in the beta or gamma band that recur at similar rates in the theta or alpha band
Isolation of MIMO Antenna with Electromagnetic Band Gap StructureAysu COSKUN
This work represents isolation of mimo antenna system with mushroom type electromagnetic band gap structure in order to reduce mutual coupling between antennas.
Isolation of MIMO Antenna with Electromagnetic Band Gap StructureAysu COSKUN
This work represents isolation of mimo antenna system with mushroom type electromagnetic band gap structure in order to reduce mutual coupling between antennas.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
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This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
myelin presentation
1. FASTAND RELIABLE WHOLE
BRAIN MYELIN IMAGING
Alireza Akhondi-Asl
Boston Children’s Hospital, and Harvard Medical School
300 Longwood Ave. Boston MA 02115 USA
3. Myelin
• Myelin is a layer of dielectric
material derived mainly from lipids
that form a sheath around neuronal
axons, cable-like projections that
transmit electro-chemical messages
along the length of cells.
• The myelin sheath around neuronal
axons is well known to be crucial to
support brain function.
• Myelin-related disorders affect an
estimated 3 million people around
the world.
• Multiple sclerosis (MS)
• schizophrenia From mayorshealthline.wordpress.com
4. Quantitative Myelin Assessment
• Unfortunately, there are no known cures for myelin-related
diseases.
• In current practice, the diagnosis and management of
these diseases hinges on the assessment of symptoms
thought to arise from absence or loss of myelin.
• There is currently no effective mechanism for in vivo
quantitative assessment of the amount of myelin in the
CNS.
• Development of myelin imaging holds out the potential of
providing pathologically specific quantitative information
about myelin content.
5. Myelin Imaging
• The T2 spectrum of water in the brain
has multiple components
• myelin-bound water (the fastest
decaying)
• the intra/extra-cellular water of the
brain
• cerebrospinal fluid
• T2 relaxometry is the most
advantageous and effective non-
invasive MRI.
• Myelin Water fraction (MWF) is
assessed from sequences that acquire
32 spin echoes spaced from 8ms to
256ms to cover the full spectrum of
T2=1/R2 decay.
• The very rapid decay of myelin-bound
water (MW) has made it challenging to
measure.
From Wikipedia
MWF=
6. Spin-echo sequence
• Echoes were first detected by Erwin Hahn in 1950.
• Total acquisition time:TRxNExNLxNS
• NS=30,NL=108,NE=32,TR=2s ~58hrs for whole brain!
• It is the most accurate T2 relaxomotery sequence.
From Wikipedia
7. T2 Spectrum Models (NNLS)
• non-negative least squares
(NNLS)
• fitting a discrete mixture of impulse
functions
• Each impulse function centered at
pre-specified T2 values across the
range of anticipated T2 values.
• Problems:
• Fails to exploit the continuity of the
true distribution of T2 in the tissue.
• Large number of unknown
parameters
• Needs strong regularization
• Very sensitive to the location of
impulse functions and utilized
threshold for MWF estimation.
• The estimated T2 values are very
inaccurate.
8. T2 Spectrum Model
• We have developed an alternative representation
• Finite mixture of continuous distributions to describe the complete
T2 spectrum.
• The fraction of the myelin-bound water is the area under the fast
component curve divided by the total area of each component
curve.
• Advantages:
• The number of parameters that must be estimated is much smaller.
• More physically realistic model of the signal.
• Easy estimation of parameters
• More accurate MWF estimation
• Very accurate T2 estimation.
• Less sensitive to the threshold.
• Less noisy MWF estimates.
9. Generalized Inverse Gaussian (GIC)
Distribution
• Three-parameter family of
continuous distributions
• Wald (Inverse Gaussian)
• Gamma
• positive support
• closed form Laplace transform
• Not heavy tailed
• Extensively used in
geostatistics, statistical
linguistics, finance…
From Wikipedia
10. Wald Distribution
• A two-parameter family of
continuous distributions with
support on (0,∞).
• It has mean and shape
parameters.
• As shape parameter tends to
infinity, it becomes more like
a Gaussian distribution.
• The Wald distribution has
several properties analogous
to a Gaussian distribution.
11. Relation to Multi-exponential
• Multi-exponential fitting is
a special case of our
model
• Wald distribution has a
closed form Laplace
transform.
• When shape parameter
tends to infinity the Wald
distribution will be impulse
function.
12. Optimization
• We are interested to estimate
the parameters of the Wald
distributions and their mixture
weights using the observed
signals at different echo times.
However, in practice, we
observe yi, a noisy version of
the signal Si .
• We assume that zero mean,
additive white Gaussian noise
is added to the signal. Si.
• It has separable Non-linear
least squares (NLLS)
formulation.
• Variable Projection
• Fast
• Less sensitive to the initializations
• More accurate
13. Carr-Purcell-Meiboom-Gill (CPMG)
sequence
• It allows observation of multiple
echoes with a single excitation.
• It has been developed in 1980s.
• It uses hard pulse to excite the
whole brain!
• Total acquisition
time:TRxNLxNS
• NS=30,NL=108,TR=2s ~1.8 hrs
for whole brain!
• It is the base of almost all of T2
relaxomotery sequences.
• Problems:
• Sensitivity to B1 inhomogeneity which
leads to stimulated echoes.
• It is not fast enough.
pubs.rsc.org
Impact of B1 inhomogeneity on the observed
echoes.
Echo Number
Amplitude
14. B1 inhomogeneity compensation
• Optimized crushers
• SAR effect
• Perfect B1
• It is very expensive.
• The extended phase
graph (EPG)
• Gives an elegant
description of
magnetization response
in multiple refocusing
pulses with arbitrary flip
angles θ.
• It is an approximation
• It cannot be used when
slice selective RF pulses
are used.
15. Fast Myelin Imaging
• 3D Grase (3D CPMG)
• 7 slices in 16 mins (NL=108)
• ~1hr and 10 mins for whole brain with the desired resolution.
• Low SNR
• T2* effect
• GRE
• It is very fast but measures T2* not T2.
• MCDESPOT
• The measurements are not reliable.
• None of them are sufficiently fast or accurate.
16. Multi-Slice 2D CPMG
• We propose here to use multi-Slice 2D CPMG sequence for myelin
imaging.
• Nobody have used it for multi-component T2 relaxometry
• Both slice Profile and B1 inhomogeneity should be considered.
• It is fast and the results are reliable
• We can easily acquire 6 slices at the same time of single slice 2D CPMG
• Total acquisition time:TRxNLxNS/6
• The distribution of the flip angles can be used by sampling the slice
profile at limited number of points.
• Small tip angle (STA) approximation
• It is invalid and must be reconsidered to achieve accurate modeling of the
signal decay curve.
• NS=30,NL=108,TR=2s ~18 mins for whole brain!
• Using Partial Fourier and parallel imaging this time can be cut to half.
• Our preliminary results also show that we can get plausible results
with just 24 echoes (We do not need 32 echoes):
• High resolution whole brain myelin imaging in (1/2)*(24/32)*18 ~7 mins.
17. Multi-Slice 2D CPMG
Multi-Slice 2D CPMG sequence. 90o excitation and 180o refocusing RF pulses and Gradient of
the first three echoes of multi-slice 2D CPMG sequence are shown.
18. Considering Slice Profile in the Solution
• If we know the RF pulses and acquisition we can simulate
Bloch equation for different T2 and B1 values to generate
T2 curves.
• It is similar to EPG but it is very precise
• It is not parametric
• We need to compute these curves one time and we can use them
• So it is fast.
• We have the same equations
• We just replace EPG formulation with Bloch formulation.
19. The Bloch Equations
• The Bloch equations named after Felix Bloch relate the
time evolution of magnetization to the external magnetic
fields, the relaxation time, and other parameters:
20. Results: Simulation
(a) The slice profile of the first and second echoes for a spin with T2=75ms and B1=1.0 inhomogeneity scale
are shown. (b) The slice profile of the first echo for T2=75ms and B1=0.8 as well as the slice profile calculated
using the STA approximation. (c) and (d) Impact of non-ideal slice selective RF pulses on the signal decay curve
when T2=75ms and T2=20ms, respectively.
21. Results: Simulation
(a) CRLB of MWF estimation using MOIG distributions where the standard deviation is
normalized by the true MWF value. (b) Relative MAE for a range of SNRs and
inhomogeneity scales for MOIG and NNLS.
22. Results: Phantom Experiments
• Two chamber phantom filled
with different levels of
gadolinium doped water
solutions.
• T2 relaxation measurements
were performed on a 3T
Siemens TRIO scanner with a
single slice (4mm thick), T2
relaxometry sequence.
• 32 echoes were acquired with
a minimum echo time of 9ms.
• 21 cm FOV was used with a
matrix size of 192x192 (in
plane resolution of 1.1x1.1 mm
squared).
(a) The observed echo at 90ms and the regions used to construct the ROI’s utilized for the
experiment. Each ROI has three voxels inside one of the red rectangles with the longer and one voxel
inside the green rectangle with the short . (b) Comparison of the distribution of normalized error in
the estimation of the fraction of the first component using MOIG and NNLS based on 630 ROI’s. (c)
Box plot of the estimated fractions using MOIG and NNLS. (d) Scatter plot of the estimated fraction of
the shortest component using MOIG versus NNLS.
23. Results: Brain Data
(a)-(b) Estimated MWF map using MOIG distributions. (c)-(d) Estimated MWF map using NNLS. (e)-(f) Estimated
inhomogeneity scale maps using MOIG. (g)-(h) Estimated inhomogeneity scale maps using NNLS approach.
24. Results: Whole brain myelin imaging
MWF maps generated via
our analysis method for
twelve slices are shown. A
20 cm FOV was used with
the matrix size of 128x96
(phase resolution of 75%)
and total scan time of 17
minutes and 10 seconds for
the acquisition of 5x6=30
slices.
25. Results: Brain Data
(a) The scatter plot of test-retest analysis of NNLS algorithm. (b) The scatter plot of test-retest analysis of MOIG. R-
squared of fitted regression line of MOIG and NNLS was 0.79 and 0.70, respectively.
26. Summary of Current Myelin Imaging
Methods
• Limitations of Current state-of-the-art methods:
• The imaging process is very slow
• Currently, state-of-the-art methods can acquire 1 slice in 3.6 mins
• To cover whole brain with sufficient resolution we need at least 30 slices.
Therefore, ~1hr and 48mins required for whole brain imaging.
• Current T2 distribution models fail to exploit the continuity of the
true distribution of T2 in the tissue.
• Estimation of model parameters is sub-optimal
• In summary, current methods are slow, do not have
sufficient resolution and accuracy.
27. Proposed Myelin imaging Framework
• Imaging: Multi-slice 2D CPMG sequence.
• We can get 30 slices in ~ 17 mins.
• 6 times faster than current imaging methods.
• T2 distribution Model: Finite mixture of Wald distributions
• Number of parameters is much smaller.
• More physically realistic model of the signal
• Less noisy MWF estimates.
• Precise inhomogeneity modeling.
• Optimal parameter estimation: Robust and reliable estimation of the
parameters of a mixture of Wald distributions can be achieved with a
well-known technique called the variable projection method.
• This allows us to rapidly solve this nonlinear estimation problem with high accuracy.
28. Conclusions
• We have developed a framework for Myelin imaging
which is fast, has sufficient resolution and accuracy.
• Clinically feasible
• High resolution
• Accurate
• Sensitive to the small changes in the myelin.