Trans: Latin prefix implying "across" or "Beyond", often used in gender nonconforming situations – Scend: Archaic word describing a strong "surge" or "wave", originating with 15th century english sailors – Survival: 15th century english compound word describing an existence only worth transcending.

Category: Uncategorized (Page 3 of 3)

How to make a AWS R server

When you need an R server and have lots of data to process, AWS is a great way to go.   Sign up of the free tier and poke around!

Creating an AWS Rstudio server: - using both the R snippet (works but the R core bits are NOT present and it will not work yet) and the JSON snippet provided - the suite being installed

Follow most of the AWS blog AMI info, with the following items:

AMI:  Amazon Linux 2 (more packages and extras v. standard)  

  • t2.micro (free tier)
  • IAM policy follows AWS blog JSON snippet
  • Security Policy contains open inbound ports 22, 8787, 3838 (the latter two for R server specific communication)
  • Append user, username:password in the blog post’s initial r studio install text (pasted into the “advanced” text box when completing the AMI setup


SSH into the EC2 instance

sudo yum install –y

sudo yum-config-manager --enable epel

sudo yum repolist


sudo yum update -y

sudo yum install -y R

sudo rstudio-server verify-installation


Access the graphical R server:

In a web browser, tack on “:8787” to the end of the Instance’s public “connect” link.  If it doesn’t load a login window (but seems to be trying to connect to something) the security policy is probably being overzealous……..


Notes on S3-hosted data:

  • S3 data is easiest to use if it is set to be public.
  • There are s3-specific tools for R, accessible as packages from CRAN directly from the R interface
  • Note data (delimited text at least) hosted in S3 will behave differently than it does locally, e.g. spaces, “na”, “null” need to be “cleaned” in R before use.  


There we have it!



DIY CMoy headphone Amp, point to point: worth it?








This is an extraordinarily simple headphone amp, and has essentially reached legendary/history status at this point.  I decided to build the original design (there are countless mods and totally different amps that hark back to this one), though opting for a wall-wart desk form factor instead of the original 9v battery tin.


I am building from the the 2008 "williamneo" blog post, as I like that point to point layout of his.  (I also could not easily procure the now ancient radioshack proto board- yes, the one shaped like a crab)  🙂



opting for a desktop form-factor and 12 volts, my little amp works fine for easy to drive headphones.... But does it actually sound better than, say, an iphone?


The truth is, while it gets much louder than a phone, the OPA jfet op amp powering the whole thing is simply NOT high end.  it will distort with too much input (after a few clicks on a phone before the phone is maxed out for reference- well below standard line/"dac" level in both home and pro audio voltage wise) and will incrementally break up with hard/loud songs on bigger headphones, as the volume and rocking out goes up- in my case, the current fostex RP evolution I have been mangling is the big cheese candidate.  the planar drivers in the RP series are definitely "very hard" to drive in the scheme of things, but anything "heavy weight" will simply not do when pushed to an accessible limit.  I CAN use smaller dynamic/efficient  headphones with ease, such as my ported and open hifiman edition S without experiencing distortion.  Still here though, it is clear this amp is a "diy/cheap access to power"- slated against the fiio e12 for example, the CMOY seems a bit.... Loose?  Not any better, that is fore sure!  (granted, the e12 is a fantastic budget amp)


Note of op amps:   the NTE and other non-OPA brand-name look alikes and electrical analogues sound terrible.  I was fussing around with the NTE variants after needing the short out resistors "R5" (very important when building:  do not use R5) when they actually blew out from my using a inversely-poled power supply by accident, and was getting frustrated as the amp was working but sounded like a making TIDAL streaming gurgle out from a cheese grater.  eventually, after a ebay shipment of brand name OPAs came, I popped one in cautiously and it turned out the opamp was the source of the.... cheese grating.

In all, a good project for skill building but falls short of anything "hifi".


Wolf Pine @ Fox Park #1 +Bonus Winter Birds

Today and yesterday, 2.19.17 - 2.20.17, have officially kicked off my first real visits to my "sit spot" (required for all adventure ed students at PSU) and commutes around campus armed with my bird rig, ready for the warmer-weather inclined birds.

Observations from the Wolf Pine @ Fox Park:

Snowshoed into Fox Park around 2:15 on Sunday, 2.19.17.

Weather:  After repeated heavy snow falls, Sunday was the first day solidly above freezing- thus a large amount of dripping and snow-condensing was happening.  My wolf pine was in a bit of a freezing puddle, with ~2 feet of snow accumulation surrounding its base.   High pressure day, bluish-grey skies and scattered wispy clouds.  Light breeze, and fairly quiet.

Upon quieting myself and my raucous snow-hoverboards, it became apparent how few birds and squirrels were about.    I could hear "whispers" and chips from passerines, but they sounded far away, likely to be lower on the hill, near the squishy earth and faux-pond.  Squirrels maybe rustled a branch or two during my sit- note the trees where about half evergreen and probably not a food source for these little mammals.  These trees  would, however, provide good coverage from avian predators...  I wonder if the squirrels have thought of that.

Perhaps the surrounding homes and intermittent (not on Sunday) construction sounds provided a safer space park wide.  Owls and to a lesser extent hawks are irked to no end by these sounds and regular but unpredictable human activity.  I have observed elsewhere in MA owls are not put off by circadian dog walkers at all;  in fact, I would glean most of my "big bird" info from the unperturbed 2 - 3 times a day dog walkers of my neighborhood.   Great horned families, bald eagles, and belted kingfisher pairs could care less about 2 dozen or more dogs pass under their homes a day, but the moment a motor boat, police cars, or loud parties occurred these unbelievable species would vanish.   I make this digression because this is a college town, and the park is surrounded by active dwellings of different sorts, including development sites.  THUS:  there were essentially no rodents/lagomorphs/etc.  (easily findable ones that is)

Speaking of which, the tracks were tough to figure out.  Heavy dogs?  Yes.  beyond that, the melting snow and dripping was creating a fairly non-descript blanket over any crazy prints.

I noticed remarkable BIG woodpecker activity, i.e. Pileated and Red Bellied/flicker- especially on my way out of the park.  Holy smokes are the pileated OCD around here!

Also Note the intersting spiraling growth pattern on this Wolf Pine limb.  It is long dead, but appears and felt denser than "ye average" pine tree.  ??

I plan to get back to my spot ASAP for more warm weather observations.  I believe this is the forecast all week!


A loud house finch and a lovely Bohemian waxwing.

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