Sebastian Raschka has shared the codes for his upcoming book "Python Machine Learning – 3rd Edition" in the below github repository. https://lnkd.in/ex7J-EY
Dec 06
Administering Magento 2 on AWS Platform
Varnish:
Configuring Varnish Server i.e. a Cache Server
https://varnish-cache.org/docs/5.1/reference/varnishd.html#http-resp-hdr-len
/opt/bitnami/varnish/varnishd
varnishd [-a address[:port][,PROTO]] [-b host[:port]] [-C] [-d] [-F] [-f config] [-h type[,options]] [-I clifile] [-i identity] [-j jail[,jailoptions]] [-l vsl[,vsm]] [-M address:port] [-n name] [-P file] [-p param=value] [-r param[,param…]] [-S secret-file] [-s [name=]kind[,options]] [-T address[:port]] [-t TTL] [-V] [-W waiter] [-x parameter|vsl|cli|builtin] [-?]
—
How to fix 503: Backend Fetch error
Give it a try; no guarantee. Purge Varnish cache as well. magento cache clearing also causes varnish cache Purge
https://community.magento.com/t5/Magento-2-x-Programming/how-to-fix-Error-503-Backend-fetch-failed/td-p/84061
—-
Configure And Use Varnish (TM)
See if your version and platform is right before applying
https://docs.bitnami.com/bch/apps/wordpress/administration/configure-use-varnish/
Deploy content
setup:static-content:deploy [-f|–force] [-s|–strategy [STRATEGY]] [-a|–area [AREA]] [–exclude-area [EXCLUDE-A
REA]] [-t|–theme [THEME]] [–exclude-theme [EXCLUDE-THEME]] [-l|–language [LANGUAGE]] [–exclude-language [EXCL
UDE-LANGUAGE]] [-j|–jobs [JOBS]] [–max-execution-time [MAX-EXECUTION-TIME]] [–symlink-locale] [–content-versi
on CONTENT-VERSION] [–refresh-content-version-only] [–no-javascript] [–no-css] [–no-less] [–no-images] [–no
-fonts] [–no-html] [–no-misc] [–no-html-minify] [–] [<languages>…]
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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Dec 05
Find answers to the questions to know more on Radar. Sure, you can apply the knowledge in sel-driving car engineering?
What is echo signal in radar?
"Noun. 1. radar echo – an electronic signal that has been reflected back to the radar antenna; contains information about the location and distance of the reflecting object. electronic signal – a signal generated by electronic means. Radar echo – definition of radar echo by The Free Dictionary" https://www.thefreedictionary.com › radar+echo
How does power density of the echo signal differ from the received power by the radar? Conceptually and in the equations?
Ans: Ae = effective area of the receiving antenna
What is the relation between G (Gain in the direction of target) and Ae? Any explanation of the equation and relation?
What are the units of the parameters in the equations?
What is the symbol used for Wavelength?
How do you calculate the distance beyond what the target cannot be detected? i.e. Rmax, give the equation and explain
How can you achieve a long distance?
To get a long distance, will Pt need to be large?
To get a long distance, will radiated energy need to be concentrated into a narrow beam?
To get a long distance, will the received energy must be collected with a large antenna?
To get a long distance, will the receiver must be sensitive to weak signals?
Is the predicted radar range very accurate or usually optimistic? why or why not?
What are the parameters that can make the predicted radar range not very accurate?
Can you describe the maximum range of a Radar just by one number?
Is it true? radar range (max) must include probability, the target type, and range possible
What are the unpredictable or statistical parameters in the equation for max range?
Is Smin = minimum detectable signal predictable in the equation?
Is target cross section (sigma) predictable in the equation?
Are meteorological conditions predictable in the equation?
What do you mean by Smin = minimum detectable signal ? Any little details in any direction?
Is Smin = minimum detectable signal: affected by noise energy?
Does Smin = minimum detectable signal: also depend on the threshold set at the output of the receiver? Why is the threshold there? What happens if you lower the threshold? Does low threshold mean less perfection?
Where does noise in the receiver originate from? Can the receiver itself introduce noise? What can be different sources of noise?
What is thermal noise power? Give the equation. Explain the concept and the equation. k* T * Bn, T in kelvin
Half-power bandwidth? Noise bandwidth? 3-DB bandwidth : what are these? What is the relation with Bn or thermal noise power if any?
What are the different sources of noise?
Galactic, Solar, Atmosphere, man made, Ground, Receiver
True or false? Noise entering the filter is Gaussian
How does Rayleigh relates to the probability density of a narrowband IF filter?
Probability of false alarm: what is the equation? What is the relation with TNR (Thermal noise ratio) and Bandwidth? Give a diagram.
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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Dec 04
Radar Equations
Describe/Explain Radar operation? i.e. for example, how is radar used to detect an aeroplane? Show radar components and how they function to detect an aeroplane and how is the distance calculated https://www.explainthatstuff.com/radar.html
What is the equation to calculate the range to a target using Radar Systems. Use speed of light in the equation. https://www.radartutorial.eu/01.basics/Distance-determination.en.html
R = c * Tr/2 , c = speed of light, Tr = travel time back and forth
R in km = 0.15 * Tr (in micro sec) , speed of light = 150 meters in 1 microsecond
c = 3 * 10 to the power 8 m/s = 3 * 100 = 300 m/ micro sec = 0.3 km/ micro sec
What is the maximum unambiguous range? c * Tp/2 = c / (2 * freq)
Tp = Pulse repetition interval
Freq = 1/Tp or Tp = 1/f
What are the factors that influence the performance of Radars?
Does Antenna gain influence radar performance? if so why and how? May be explain with equations in addition to giving conceptual explanation
Does Antenna effective aperture influence radar performance? if so why and how? May be explain with equations in addition to giving conceptual explanation
Does Transmitter power influence radar performance? if so why and how? May be explain with equations in addition to giving conceptual explanation
Does System losses influence radar performance? if so why and how? May be explain with equations in addition to giving conceptual explanation
Does Radar cross section influence radar performance? if so, why and how? May be explain with equations in addition to giving conceptual explanation
What is the power density for Radars? Does it relate to receiver anyway? Can you give equations for power density for directive and isotropic antennas?
What is the uncommon parameter in the equation of power density for directive and isotropic antennas?
How do you calculate average transmitter power from Peak power?
Is average power a function of pulse width (tau), Tp – pulse-repetition period?
What is the power density of the echo signal?
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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Dec 03
Artificial Intelligence to Watch
These Scientists Are Trying to Build Powerful Computers Inspired by Our Brains
These Researchers Are Getting Us Closer to Making Contact with Aliens
Scientists Are Racing to Eliminate the World’s Fastest Spreading Tropical Disease
The U.K. Startup Trying to Change the Way the World Gets its Energy
Dec 02
Magento 2 : installation/configuration/operation issues and Solutions
"The Component Dependency Check status never changes. In some cases, the status of the Component Dependency Check doesn’t change, even after you try to correct issues. In that case, you can either delete or rename files named <magento_root>/var/.update_cronjob_status and <magento_root>/var/.setup_cronjob_status and try running the Component Manager again."
https://devdocs.magento.com/guides/v2.3/comp-mgr/trouble/cman/component-depend.html
Dec 02
Radar Details: Radars in relation to self-driving vehicles
Irrespective you see the term ‘self-driving vehicles’ or not: the answers to these questions are related to self-driving vehicles.
What are the different types of Radars?
What is a Pulse Radar?
What is a Continuous Wave Radar?
What is a Surveillance Radar?
What is MTI-Moving Target Indication?
What is a Pulse Doppler Radar?
What is a tracking Radar?
What is a Synthetic Aperture Radar?
What is a multi function Radar?
What is the frequency of a signal?
What is the wavelength of a signal?
How does frequency relate to speed of light?
Give the equation of Frequency using wavelength?
Are Frequency and Wavelength directly proportional?
What is the Amplitude of a Signal?
For frequencies 1 GHz and 3 GHz which one has more/bigger wavelength?
If you mix two signals — what will happen? Define and explain the term Constructive, Destructive, Partially Constructive, noise. Can you show them visually/pictorially? What are the related devices that can perform these functions?
What are the different IEEE Radar Bands?
Will Radars in different Bands have same characteristics and applications?
Lower or Higher frequency band what can give long range detection? Why? Think in terms of antennas and powers?
What is SNR? Give the generic/conceptual equation.
How is SNR commonly measured in?
What is decibel? What is the relation between Decibels and SNR?
Give the equation for SNR in Decibels? Hint: Log10
—
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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Dec 02
Radar/Lidar Detection and Self-Driving Agents
What are basic Radar functions? Whatever comes to your mind? Though the goal is not to find core radar applications; however, functions of radars that are used in the applications.
What is the goal of the radar function named: Detection? Answer, in terms of signals
Does radar take images of an area? if so, 2D or 3D? Give more details.
Is Radar for only finding the location of the target? Can it give continuous locations? What do we call this concept?
What is a trajectory? what is trajectory detection? How can you use Radars for trajectory detection? You do not have to be technically correct? Just guess and think.
How do these detection, trajectory finding, and imaging (if any) relate to Autonomous Vehicles? How can you use these concepts? i.e. How are these concepts used if used at all.
Can you use any Machine Learning concepts in Detecting? After, you collect all the data (signal, sensor data) — how can you use Machine Learning for the detection? How does the engineering concepts before ML were used for detection?
Can detection be just exact position or trajectory? Of finding the probability of finding or false alarms can be useful as well?
What are probabilities of detection, and false alarms when it comes down to detection? Did you set up alarms for your antivirus software? Were they ever false alarms? Do false alarms decrease when you configure for more strict security?
What are some measurement parameters for tracking?
Can you use accuracy in range, angle, velocity for tracking? For angle measurements will you use degrees or radians? Why and why not? Pros, cons? any future directions?
What are spatial resolution, contrast, dynamic range when it comes dowsn to imaging from Radars for detection? Do LiDAR and Cameras when used for Self-driving cars have these features? Any relation, correlation in any direction?
What is the primary threat in the received for detection/tracking?
How does signal to interference Ratio influence the detection/tracking/imaging as well as how does that influence the measurements of the detection/tracking/imaging?
What do Radars measure?
Can you find Range/distance, Angular Direction, Radial Velocity, Target Size (RCS – Radar Cross Section) using Radars.
What are the basic parts of Radar?
Define and give some details of the radar component: Transmitter
Define and give some details of the radar component: Duplexer
Define and give some details of the radar component: Antenna
Define and give some details of the radar component: Receiver
Define and give some details of the radar component: Data Processing
Define and give some details of the radar component: Display
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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Dec 02
Tracking, Detecting, and Radar Systems: Foundational Knowledge for Autonomous Vehicle Engineering
Radar Systems
Lecture 1:
What is RADAR? What does it stand for?
What is Radio Detection and Ranging?
What kind of signal does a radar sends?
What is Electromagnetic signal? What is an Electromagnetic system?
Some details: https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html They are all around
What are some of the applications of Radar?
Can you use Target Discrimination using Radar?
Is there any use of Radar in Fire Control? Air traffic control? How? Can you describe or explain?
What is the use of radar in Law Enforcement and highway safety?
Can radar be used for collision avoidance? How that might work?
What is the use of Radar in autonomous vehicles? What are the pros and cons of Radar use in autonomous vehicles? https://blogs.nvidia.com/blog/2019/04/15/how-does-a-self-driving-car-see/
What are the different types of Radars?
Can you explain the difference among Monostatic, Bistatic, and Multistatic radars? Where and how they are appropriate to be used?
Can they be used alternatively?
https://www.sciencedirect.com/topics/engineering/multistatic-radars
What is passive radar?
What is Lidar? How does it compare with radar?
What is the advantage of Monostatic radar over Bistatic and Multistatic radars?
What are the advantages and disadvantages of Bi/Multi-static radars? What are limitations? How can you relate them to Autonomous vehicles?
For line of sight, what is better? Mono, Bi, Multi?
For costs, what is better? Mono, Bi, Multi?
For deployment, what is better? Mono, Bi, Multi?
what is more complex? Mono, Bi, Multi?
What is Radar Cross section? Who gets better Cross section? Mono, Bi, Multi? https://en.wikipedia.org/wiki/Radar_cross-section
What is Covert Operation? https://www.sciencedirect.com/topics/computer-science/covert-operation
What provides better Covert Operation? Mono, Bi, Multi, passive/active?
What are the types of sensors used by Radar systems? Think in terms of where they get the energy?
What are differences between active sensor and passive sensor? In use cases, how do they differ? Can you give examples of their use? What will you use for autonomous vehicle applications? and Why?
Which one provides better detectability? Which one has observable range? (Active or passive) any details? Can you relate in any direction?
Give examples of other types of sensors? Considering how are they manufactured?
What are the use of Optical/IR sensors?
What are the use of Acoustic sensors?
What are the use of some other types of sensors?
For applications such as Ground surveillance/reconnaissance/ID Laser Targeting, Night Vision, Space Surveillance, missile seekers what kind of sensors are used and why? (among Optical/IR/Acoustic)
Is Sonar Optical or Acoustic or IR?
For Blast Detection and Troop movement detection what types of sensors are used? Think: Optical, IR, Acoustic, Chemical, Biological, Radiological? Can you explain why?
What does LiDAR use? Light or sound or something else?
Does LiDar use antennas?
What is CCD Optics? Who use CCD Optics? i.e. RADAR or LiDAR?
What is more robust against interferences? LiDAR or Radar?
What is the primary disadvantage of Lidar to be used in Autonomouse vehicles?
Is refresh rate in Lidar high or low? Is that an advantage or disadvantage?
What has longer range? LiDAR or Radar?
What is an alternative technology than Lidar for Autonomous Vehicles? Think other than Radar? Is radar good anyway?
Can you use cameras for Autonomous Vehicles as eyes/for vision? If so what can be some of the advantages over Lidar? What are disadvantages?
Can cameras be really used ? Are they really used? If used, why are they used? If not, why not? What are the possible improvements (or required improvements) in Camera technologies to make them reliable? Do you think they are reliable now?
Who can classify traffic signals more easily? Lidar or Cameras?
Can Lidars see colors of the objects (detected)?
What are some disadvantages of using Cameras for Autonomous Vehicles?
Is it easy to extract information from Camera images? What about Lidar? why is that? Can you eliminate the limitations if any for any one of them? How? How can the information extraction be enhanced in either case?
How do you get range/distance information from Cameras? Can you use Lidar and Cameras together? How? Advantages, disadvantages? How will you fit (make them work together) the technologies in the car?
Dec 02
C++ Libraries
#include <iostream> #include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
By
Sayed Ahmed
BSc. Eng. in Comp. Sc. & Eng. (BUET)
MSc. in Comp. Sc. (U of Manitoba, Canada)
MSc. in Data Science and Analytics (Ryerson University, Canada)
Linkedin: https://ca.linkedin.com/in/sayedjustetc
Blog: http://Bangla.SaLearningSchool.com, http://SitesTree.com
Online and Offline Training: http://Training.SitesTree.com
Get access to courses on Big Data, Data Science, AI, Cloud, Linux, System Admin, Web Development and Misc. related. Also, create your own course to sell to others to earn a revenue.
http://sitestree.com/training/
If you want to contribute to the operation of this site (Bangla.SaLearn) including occasional free and/or low cost online training (using Zoom.us): http://Training.SitesTree.com (or charitable/non-profit work in the education/health/social service sector), you can financially contribute to: safoundation at salearningschool.com using Paypal or Credit Card (on http://sitestree.com/training/enrol/index.php?id=114 ).
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