Nabin K. Malakar, Ph.D.

I am a computational physicist working on societal applications of machine-learning techniques.

Research Links

My research interests span multi-disciplinary fields involving Societal applications of Machine Learning, Decision-theoretic approach to automated Experimental Design, Bayesian statistical data analysis and signal processing.


Interested about the picture? Autonomous experimental design allows us to answer the question of where to take the measurements. More about it is here...


I addition to the research, I also like to hike, bike, read and play with water color.

Thanks for the visit. Please feel free to visit my Weblogs.

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Tuesday, December 10, 2013

Heading to San Francisco For #AGU13

Bias Correction of high resolution MODIS Aerosol Optical Depth in urban areas using the Dragon AERONET Network
Nabin K Malakar, Adam Atia, Barry Gross, Fred Moshary, Samir A Ahmed,
The City College of New York, New York, NY, United States.
David J Lary
University of Texas at Dallas, Richardson, TX, United States.

Aerosol optical depth (AOD) is widely used parameter used to quantify aerosol abundance. Satellite retrievals of aerosols over land is fundamentally more complex than aerosol retrieval over oceans. Due to wide coverage and the extensive validation the Moderate Resolution Imaging Spectroradiometer (MODIS), on board the Terra and Aqua satellites are the workhorse instrument used to retrieve AOD from space. However, satellite algorithms of AOD are extremely complex and depends strongly on sun/view geometry, spectral surface albedo, aerosol model assumptions and surface heterogeneity. This issue becomes even more severe when considering the new MODIS 3 km aerosol retrieval products within version 6. To assess satellite retrievals of these high resolution 3 km products, we use the summer 2011 Dragon AERONET data to assess accuracy as well as major retrieval bias that can occur in MODIS measurements.

In this study, we explore in detail the factors that can drive these biases statistically. As discussed above, our considers multiple conditions such as surface reflectivity at various wavelengths, solar and sensor zenith angles, the solar and sensor azimuth, scattering angles as well as meteorological factors and aerosol type (angstrom coefficient) etc which are used inputs are used to train neural network in regression mode to compensate for biases against the Dragon AERONET AOD values.

In particular, we confirm the results of previous studies where the land cover (urban fraction) appears to be a strong factor in AOD bias and develop a NN estimator which includes land cover directly. The algorithm will be tested not only in the Baltimore/Washington area but assessed in the general North East US where urban biases in the NYC area have been previously identified.

Saturday, November 9, 2013

EMEP Poster Presentation

Nabin Malakar
in collaboration with
Lina Cordero, Yonghua Wu, Barry Gross, Fred Moshary, Mike Ku

Prior efforts to connect surface PM2.5 to satellite retrieval of aerosol optical depth (AOD) have been mainly made based on statistical approaches connecting AIRNow PM2.5 measurements and satellite AOD for different seasons and geographic regions. However, this approach does not account for complex aerosol behavior including planetary boundary layer (PBL) dynamics. In another approach used operationally within the IDEA (Infusing satellite Data into Environmental air quality Applications) product, the use of a global model (GEOS-CHEM) is used to estimate on a daily basis, the spatial relationship between forecast PM2.5and column path AOD, which can then be used with satellite AOD estimates. However, one difficulty with the GEOS-CHEM approach is the poor spatial resolution symptomatic of global models with a spatial resolution of 2.5 degrees, which fails to particularly resolve issues in the urban/nonurban interface To improve on this, the WRF/CMAQ model is a high-resolution algorithm that accounts for physically based meteorological factors and surface boundary conditions including emission inventories to estimate particulate concentrations and vertical distributions; therefore, it is considered in our work.
Because of the complexity observed in the PM2.5-AOD relationship, our focal point is the application of a neural network for better describing the non-linear conditions surrounding the PM2.5-AOD environment while at the same time investigating other dependences such as additional factors or seasonal changes. Neural networks have proven to perform well in different areas of study, including atmospheric sciences where many complex relationships cannot be sufficiently understood by using statistical approaches. As part of our analysis, we first explore the baseline effectiveness of AOD and PBL as strong factors in estimating PM2.5 in a local experiment using data collected at one site in New York City. Then, we expand our analysis to a regional domain where daily estimations are compared based on site location and season. In our local test, we find very good agreement of the neural network estimator when AOD, PBL, and seasonality are ingested (R~0.94 in summer). Next, we test our regional network and compare it with the GEOS-CHEM product. In particular, we find significant improvement of the NN approach with better correlation and less bias in comparison with GEOS-CHEM. Further, we show that further improvements are obtained if additional satellite information, including satellite/view geometry and land surface reflection, is included. Finally, comparisons with WRF/CMAQ PM25 are included. 

Presenting Poster


About 2013 EMEP Conference
Environmental Monitoring, Evaluation and Protection in New York: Linking Science and Policy

Holiday Inn - Wolf Road
205 Wolf Road, Albany, New York
November 6 & 7

This conference brings together policy makers and nationally renowned scientists to share information on environmental research initiatives in New York State.
Production and use of energy impose one of the greatest burdens on our environment of any human activity. The Environmental Monitoring, Evaluation, and Protection (EMEP) Program at NYSERDA provides scientifically credible and objective information on environmental impacts of energy systems to assist the state in developing science-based and cost-effective policies to mitigate impacts. The EMEP program supports policy-relevant research in order to enhance understanding of energy-related environmental issues.

Friday, September 27, 2013

Monty Hall’s #paradox

Consider an urn , with 15 blue balls, and 10 red balls, and an urn , with 10 blue balls, and 15 red balls. We select randomly one urn (with probability 50% for each urn).
We draw a ball, which turns out to be blue, and we put it back in the urn, Now, we draw a (second) ball. What is the probability that this (second) ball is blue?

Solution after the break!

Sunday, September 22, 2013

India launching first #Mars mission #Mangalyaan

After the successful mission to Moon (Chandrayaan-I), India is heading to Mars!

Indian Space Research Organisation (ISRO) is launching  Mangalyaan using the Polar Satellite Launch Vehicle (PSLV). The planned launch date is Nov 5th, 2013.   The Mangalyaan will carry five scientific payloads which include: 
  1. Methane Sensor For Mars (MSM), 
  2. Mars Color Camera (MCC), 
  3. Mars Exospheric Neutral Composition Analyzer (MENCA), 
  4. TIR Spectrometer (TIS), and 
  5. Lyman-Alpha Photometer (LAP). 
It will also use Indian Deep Space Network (IDSN), as well as NASA deep space network for navigation and tracking during its mission. The spacecraft is expected to take nearly 300 days to reach the Martian orbit.

It is quite impressive that ISRO has pulled it up in such a short time. The next fuel-saving Hohmann transfer orbit opens  in 2016. If successful, ISRO would become the fourth space agency to reach Mars, after Roscosmos, NASA, and ESA.

Thursday, September 19, 2013

LEGO Ultimate (Useless) Machine

Ultimate machine or useless machine are designed to operate in such a way that it will switch itself off, whenever turned on.
Here is one version:
Free Plans, Purchase Kits, Machines & More:
There are variety of modifications made. This one is amusing:

And... this is an awesome construction LEGO3.


Thursday, September 12, 2013

@NASAVoyager leaves the solar system, officially

Space, the final frontier!

The recent news is that Voyager has left the solar system.
We have made it! (Well, it has been 1 year! )

NASA hosted a news conference on Thurs., Sept. 12, 2013, to discuss NASA's Voyager mission.
The briefing was held at NASA Headquarters in Washington and air live on NASA Television and the agency's website.
The recorded video is highly recommended

Monday, August 19, 2013

जब सम्म #यूवा को चेत खुल्दैन, तब सम्म देश को चान्सै छैन!

नेपालको मूल समस्या के हो भनि धेरै जना घोत्लिए,
देशी-बिदेशी अजासु (अति-जान्ने-सुन्ने) ले प्रयास गरे 
पैसाको खोलो बगाए, तर पत्ता लागेन  रे !

कहिले राजालाई दोष दिइयो, कहिले कांग्रेस, त कहिले कम्म्युनिस्ट 
जो सत्ता मा छ दोष  उसैको हुनेनै भो!
सबै प्रयोग गरियो, नेपालमा 
कहिँ नभएको प्रयोग पनि गरियो 

तर मेरो विचार मा यो चित्र ले सहि समस्या को जड केहो भन्ने प्रस्ट देखाउछ 
pic via @puruad (ask him for source)

झण्डा बोकेको भर मा आजको टर्ने भए पछि के को टेन्सन?
अझ त्यति गरेर मज्जा नलागे काम गरिखाने को बाटो छेकेर साईकल को हावा फुस्काउन पाइन्छ
मारकाट र कुटपिट को रोमान्स त् झन छदैछ!  

जब सम्म #यूवा को चेत खुल्दैन, तब सम्म देश को चान्सै छैन!
जंगबहादुरले रोलक्रम राखेका थिए, राणाजीहरु त् गए, तर प्रथा अझै छ 
झर्ला र खाउला भनेर कुरुन्जेल समय बितिसक्ने छ
जाग नेपालका युवाहरु, 
नत्र भो कुरै नगरौ!


Wednesday, August 7, 2013

Is the #Sun's Magnetic Field about to Flip?

(Ans: Yes!)
We are familiar with the 11 year long cycles of the Sun. When the solar activities are peaked, we call it  Solar max [Link 1, Link2]. During Solar Max, there are many sunspots, prominences, and solar storms (solar flares, and coronal mass ejections). The magnetic field of the Sun protects solar system from cosmic rays. Cosmic rays are high-energy particles generated during violent events in the galaxy.  The solar reversal can have big impact as Cosmic rays could pose dangers to astronauts and space instruments.

Read more..

Watch the video which narrates the article:

Few weeks ago, there was this video showing a persistent hole in the Sun's Corona


Thursday, May 9, 2013

tactile Simultaneous Localization and Mapping using Whiskers

There are few ways of learning. Based upon the methods the learners are classified as:

  • visual learners;
  • auditory learners;
  • kinesthetic learners or tactile learners

In robotics, we have seen examples of using audio and visual sensors to learn the surroundings. I came across this tactile learners called Shrewbots (Or may I call them the whisker-bots). Shrewbots use the technique called tSLAM (tactile Simultaneous Localization and Mapping) to sense its environments by using few actuated whiskers. See the video:

Below you can see the tSLAM at work!

Read more:
“Simultaneous Localization and Mapping on a Multi-Degree of Freedom Biomimetic Whiskered Robot,” by Martin J. Pearson, Charles Fox, J. Charles Sullivan, Tony J. Prescott, Tony Pipe, and Ben Mitchinson from the Bristol Robotics Laboratory and Sheffield University's Adaptive Behaviour Research Group, was presented this week at ICRA 2013 in Germany. via ieeeSpectrum

Plus, you should follow BotJunkie to see some weird and interesting stuffs:


Tuesday, April 2, 2013

#NASA's @AstroRobonaut Challenge

Here is the challenge:
Improve the vision algorithms of  @AstroRobonaut, and win some money.

A Robonaut is a dexterous humanoid robot built and designed at NASA Johnson Space Center in Houston, Texas. You can join him on facebook:

Saturday, March 30, 2013

We Are the Explorers! #NASA

So, after a successful public funding effort (link), we will get to see a 30 sec version of this inspiring NASA video before the movie Star Trek: Into Darkness is run on the screen!
Current funding will allow it to be featured only on major cities, so the organizers have updated their goal... to expand the reach from 59 movie theater screens to 750 screens!
Here is the link to read more about the fund raising details:
We need to inspire future generation!

Tuesday, February 12, 2013

Li-ion battery issue of Boeing's Dreamliner 787

Santosh KC writes about a recent incident involving Li-ion battery in the Boeing's 787 Dreamliner ...
Boeing 787 Dreamliner is supposed to be one of the best planes in terms of its design, fuel efficiency and advancement of the technology. Everyone understands that every plane requires battery for backups or some electrical applications. However, the Dreamliner uses the Li-ion battery based on Lithium cobalt oxide (LiCoO2) extensively. It is because it is designed in such a way to use electrical signals for control system unlike the earlier planes with hydraulic control system.  All 787s have two Li-ion batteries weighting around 63 pounds, compared with 106 pounds for nickel-cadmium battery in 777s, and holds electric charge of 65 ampere-hours, compared with 47 ampere-hours for 777 battery and measures 8.6 inches tall by 11 inches wide in dimensions... Overheating and catching fire by Li-ion battery in laptop, smartphones and electric vehicles has already been reported in many instances. However, such issues were not reported in aircraft because the Li-ion battery was not used for the electrical system in the planes to the extent as in Dreamliner.  
Read more here...

Li-ion battery issue in Boeing’s 787 Dreamliner


Monday, February 11, 2013

Linked profile, 200 millions and top 5% views

Recently I received a Linkedin message, stating that my profile was among one of the top 5% being viewed in the network. With about 1 profile view per day, on the average, I am guessing that you may also have received one... or will be getting one.
Here are my stats:
The stat went nicely upwards after this paper was online:
"Estimation and Bias Correction of Aerosol Abundance using Data-driven Machine Learning and Remote Sensing"
(This was presented in CIDU 2012, in Colorado;  available here at ieee site:

Anyways here are two links that you will get if you get the email about 5%:


Tuesday, February 5, 2013

Domain Theory of Bird's Orientation ? #Fun

Does a bird have any preferred direction or orientation while lining up on the wire?

Well, look up the wire, in the morning or evening time when they are lined up for social gathering. They remind me of the domain theory of magnetism. Or rather the spin-spin coupling of the Ising model. The Ising model consists of discrete variables that represent magnetic dipole moments of atomic spins that can be in one of two states (+1 or −1). The spins are arranged in a lattice, allowing each spin to interact with its neighbors. Similarly, the interaction between these birds can not be more than one bird distance away on both sides! Since most of them tend to be aligned, the awkward amount of energy that they need to stay in reverse direction should be too high.

Here is a video showing the flight of the birds sitting on the tree branches. Clearly, their domain is separated from the ones sitting on the wire.

Tuesday, January 1, 2013

Ten most viewed notes in 2012

Wishing you a happy
New Year 2013!!

Posts (


Posts (ajabgajab)

Jan 12, 2008, 4 comments
May 16, 2008, 3 comments