dynamical system

Systemic violence enables interpersonal violence. A society that denies some of its members autonomy, safety, healthcare, etc., makes those people vulnerable to more direct abuses, since they are denied their own resources and must depend on the goodwill of people who have power over them.

In such a culture there will always be individuals who take advantage of that vulnerability to do further harm.

Mary Cartwright (1900-1998) was a British mathematician who was the first to analyse a dynamical system with chaos. She was the first woman to obtain a first-class degree in Mathematics from the University of Oxford.

She also obtained her PhD in Oxford, and went on to work as a researcher in Cambridge. In 1930 she began work on the theorem that now bear her name (Cartwright’s theorem). She was elected as a Fellow of the Royal Society in 1947, the first female mathematician to be offered this honour.

Final Fantasy XV, aka ‘Please, Hajime Tabata, Stop It.’

I just spent the last few hours of 2016 finishing FFXV. 

Do I have feelings? You bet. A LOT OF FEELINGS. 

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Ah, Final Fantasy XV. Development hell resident. The forever-morphing former member of the Fabula Nova Crystallis collection. Formerly known as Versus XIII. We’ve been through a lot. You gave us all you could, but we all know that you could have given us so much more. 

You had it in you.  

(This is going to be a long one. A LOT of spoilers inside. EDIT: now with MUSIC portion!)

Keep reading

In dynamical systems, a bifurcation occurs when a small change made to the parameter values of a system causes a sudden qualitative or topological change in its behaviour. The name “bifurcation” was first introduced by Henri Poincaré in 1885 in the first paper in mathematics showing such a behavior.

Even in simple systems such as the logistic map, bifurcations can arise and introduce chaos. A rough description of chaos is that chaotic systems exhibit a great sensitivity to initial conditions. The animation depicts a cobweb diagram of the logistic map and shows its chaotic behavior.

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Unveiling the Mandelbrot Set.

Back in the 1970s and 1980s, mathematicians working in an area called dynamical systems made use of the ever-advancing computing power to draw computer images of the objects they were working on. What they saw blew their minds: fractal-like structures whose beauty and complexity is only rivalled by Nature itself. At the heart of them lay the Mandelbrot set, which today has achieved fame even outside the field of dynamics. 

The Mandelbrot set is a fractal. Fractals are objects that display self-similarity at various scales. Magnifying a fractal reveals small-scale details similar to the large-scale characteristics. Although the Mandelbrot set is self-similar at magnified scales, the small scale details are not identical to the whole. In fact, the Mandelbrot set is infinitely complex. Yet the process of generating it is based on an extremely simple equation involving complex numbers.

The Mandelbrot set is an incredible object that equals infinity. It’s really amazing that the simple iterated equation Z = Z^2 + C can produce such beautiful works of mathematical art.

Open Sourcing Screwdriver, Yahoo’s Continuous Delivery Build System for Dynamic Infrastructure

By James Collins, Sr. Director, Developer Platforms and Services, and St. John Johnson, Principal Engineer

Continuous Delivery enables software development teams to move faster and adapt to users’ needs quicker by reducing the inherent friction associated with releasing software changes. Yahoo’s engineering has modernized as it has embraced Continuous Delivery as a strategy for improving product quality and engineering agility. All our active products deliver from commit to production with full automation and this has greatly improved Yahoo’s ability to deliver products.  

Part of what enabled Yahoo to make Continuous Delivery at scale a reality was our improved build and release tooling. Now, we are open sourcing an adaptation of our code as Screwdriver.cd, a new streamlined build system designed to enable Continuous Delivery to production at scale for dynamic infrastructure.

Some of the key design features of Screwdriver have helped Yahoo achieve Continuous Delivery at scale. At a high level these are:

  • Making deployment pipelines easy
  • Optimizing for trunk development
  • Making rolling back easy

Easy deployment pipelines: Deployment pipelines that continuously test, integrate, and deploy code to production greatly reduce the risk of errors and reduce the time to get feedback to developers. The challenge for many groups had been that pipelines were cumbersome to setup and maintain. We designed a solution that made pipelines easy to configure and completely self-service for any developer. By managing the pipeline configuration in the code repository Screwdriver allows developers to configure pipelines in a manner familiar to them, and as a bonus, to easily code review pipeline changes too.

Trunk development: Internally, we encourage workflows where the trunk is always shippable. Our teams use a modified GitHub flow for their workflows. Pull Requests (PRs) are the entry point for running tests and ensuring code that entered the repository has been sufficiently tested. Insisting on formal PRs also improves the quality of our code reviews.

To ensure trunks are shippable, we enable functional testing of code in the PRs. Internally, this is a configuration baked into pipelines that dynamically allocates compute resources, deploys the code, and runs tests. These tests include web testing using tools like Selenium. These dynamically-allocated resources are also available for a period after the PR build, allowing engineers to interact with the system and review visual aspects of their changes.

Easy rollbacks: To allow for easy code rollbacks, we allow phases of the pipeline to be re-run at a previously-saved state. We leverage features in our PaaS to handle the deployment, but we store and pass metadata to enable us to re-run from a specific git SHA with the same deployment data. This allows us to roll back to a previous state in production. This design makes rolling back as easy as selecting a version from a dropdown menu and clicking “deploy.” Anyone with write access to the project can make this change. This helped us move teams to a DevOps model where developers were responsible for the production state.

The successful growth of Screwdriver over the past 5 years at Yahoo has today led to Screwdriver being synonymous with Continuous Delivery within the company. Screwdriver handles over 25,000+ builds per day and 12,000+ daily git commits as a single shared entrypoint for Yahoo. It supports multiple languages and handles both virtual machine and container-based builds and deployment.

External image

Screwdriver.cd’s architecture is comprised of four main components: a frontend for serving content to the user, a stateless API that orchestrates between user interactions and build operations, the execution engines (Docker Swarm, Kubernetes, etc.) that checkout source code and execute in containers, and the launcher that executes and monitors commands inside the container.

The diagram below shows this architecture overlaid with a typical developer flow.

External image

To give some context around our execution engines, internal Screwdriver started as an abstraction layer on top of Jenkins and used Docker to provide isolation, common build containers, etc. We used features provided by Jenkins plugins to leverage existing work around coverage and test reports. However, as Screwdriver usage continued to climb, it outgrew a single Jenkins cluster. So in order to grow to our needs, we added capabilities in Screwdriver that allowed us to scale horizontally while also adding capabilities to schedule pipelines across a number of Jenkins clusters. As we scaled Screwdriver, we used less from Jenkins and built more supporting services utilizing our cloud infrastructure. The open-source version is focused on Kubernetes and Docker Swarm as our primary supported execution engines.

In the coming months we will expand our offering to match many of the features we have internally, including:

  • Mechanism to store structured build data for later use (last deployed version, test coverage, etc.)
  • Built-in metric collecting
  • System-wide templates to enable getting started quickly
  • Log analysis to provide insights to developers

Please join us on the path to making Continuous Delivery easy. Visit http://screwdriver.cd to get started.

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Seems Very Interesting

Part 21

Quantum Phase Space - In mathematics and physics, a phase space of a dynamical system is a space in which all possible states of a system are represented, with each possible state corresponding to one unique point in the phase space.

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i feel like now’s a good time to remind everyone that women can be abusive - to men, other women, nonbinary people, anyone. interpersonal abuse dynamics do not necessarily reflect systemic power dynamics (tho those can obviously play a part - it’s just not a necessary component). if you’ve been abused by a woman - it was not your fault, and it was real, and you deserve support and recognition for your pain. 

i feel like as a wlw when you’re abused by another woman it can take on an extra layer of pain - there’s this fear that by admitting this happened to us we are confirming homophobic stereotypes. but that’s just not true. our lives are our own and we should be allowed to focus on our recovery, not be expected to be the perfect representation of our community. 

if you’ve gone through this, i’m so sorry. we deserve so much better. i hope you’re all doing well, or get there soon.

flickr

Venus and the Crescent Moon - April 6, 2016 by Joseph Brimacombe
Via Flickr:
Taken with a Canon 5D Mk II and 28-300 mm lens.

anyway i got three prelim classes transferred, i passed three by exams, and i’m taking one this semester, so once i finish difftop i’m done with dat prelim life

of course that means people will expect me to pick a research area and start doing real math, which is scary

Threw my sword for the kill shot. Didn’t work. Quick thinking and accidental features save the day. Also in evidence: dynamic music system copy+pasted from the main game, corpses removing themselves, guard IKing his hand to try to block your weapon.

sparkpulse  asked:

I kind of need you to settle something for me. I have a friend who thinks the "Dynamic Nuclear Generation System" from Transformers Prime should be shortened to "dynges" of all things, whereas I maintain that the thing they were calling it was, in fact, "dingus." Which is, in fact, this friend's actual nickname. Please explain to Dingus that it is spelled "dingus" just like you guys already have it in the wiki! Thank you!

I think logically, in universe at least, it would be shortened to “DNGS,” (which is how the closed captions for the episode spelled it) and that’s just phoenetically pronounced “dingus” by the characters. We go with “Dingus” because that was the spelling used in the in-universe Raf’s Notes on the Hub website.

                                              YIN & YANG

             Like two sides of a coin there are two sides of Zeke that ultimately make him who he is. There’s a part that wishes to nurture, love, guide, and please - while the other part seeks to conquer, dominate, fight, and protect.  Complementary (rather than opposing) forces inside of himself that form a dynamic system in which holds him together. The more assertive side coming from his beast. Long story short, without one the other simply cannot survive; two entities bundled together to make a working soul. Just like he has his own thoughts however so does the wolf dwelling inside. Although It cannot truly speak, it often sends communication through images rather than words - possessing feelings of it’s own and being highly intelligent.

            Among his kind, this submissive and dominant behavior is somewhat of an anomaly - Zeke being outside of the normal pack structure when it comes to his species. On the topic of romantic/sexual relationships, Zeke would be classified as the epitome of versatility. The more human side of him wishes to submit and simply be taken care of while the beast wishes to lead and take charge. Alas this results in Zeke craving both dominant and submissive roles within a sexual/romantic relationship. If both sides aren’t satisfied - chances are he will become unhappy and things won’t work out.

so then… its not a matter of establishing the correct kind/value/system of government - rather it is a matter of recognizing that no rigid proscribed government will ever reflect the best community over time – instead community is best served by dynamic systems that involve constant formative assessment and revision

connections within these communities need to be accessible for human sensing via multiple experiential avenues (language, direct interaction including visual, touch, auditory etc cues , instinctive action, behavior, ritual/culture) on an ongoing basis that is intermittent (with solitude) but regularly available. recognition, valuing and prioritizing of these connections as necessary to the unavoidably interdependent nature of human survival is also key.

To anyone saying Undertale’s cavern is impossible, it’s not really. Son Doong cave in Vietnam is the largest known cave in the world, it’s carved out by a river eroding the limestone. It is 9 kilometers long, going deeper and deeper, with holes in the ceiling that allow sunlight to shine in growing entire forests with vegetation. just like the hole you fall into in Undertale. The cavern is so large that clouds form inside it, causing it to have its own dynamic weather systems, it’s entirely possible that such a cave in a colder location could have snow form and fall inside the cave. Of course, if such a cave managed to erode past the limestone layer and reach a volcanic vein, such a location like Hotland could indeed exist.