43 Matching Annotations
  1. Dec 2023
    1. lossy compression: drop some of your data in a way that doesn’t impact your final results too much.

      If parts of your data don’t impact your analysis, no need to waste memory keeping extraneous details around.

  2. Sep 2023
  3. Mar 2023
  4. Feb 2023
    1. I used to use TimeSnapper for that. The classic version is free.It did use a crapload of disk space though (20GB per week?), and most of the data is almost identical, so I started designing an algorithm to store only the differences between images before realizing I had reinvented video codecs... so I just made a ffmpeg one liner to convert the image sequences to mp4 :)

      An interesting story, but also very inspiring to me.


  5. Oct 2022
    1. Current ruby releases generate *.tar.gz, *.tar.bz2, *.tar.xz, and *.zip. But I think we can stop generating *.tar.bz2. I think *.tar.bz2 are less merit. For better size, *.tar.xz exist. For better compatibility, *.tar.gz and *.zip exist.
  6. Jun 2022
  7. Dec 2021
  8. Jan 2021
  9. Jul 2020
    1. Imagine a large population of people living, seeing, learning, doing and generally going about their lives. As they do so, they accumulate beliefs. Depending on how smart they are, they also compress beliefs via abstraction, metaphor, subconscious pattern-recognition circuits, muscle memory, ritual, making and consuming art, going p-value fishing, exploring tantric sex, generating irreproducible peer-reviewed Science! and so on.

      Compression of knowledge through abstractions ~ mental models.

    1. compressed public keypk2={bi t,(t1,t2,t3)∈(Z2e2)3,A∈Fp2,ent_bi t,r∈Z256}
  10. May 2020
    1. You should construct evergreen (permanent) notes based on concepts, not related to a source (e.g. a book) or an author.

      Your mental models are compression functions. You make them more powerful by trying to use them on new information. Are you able to compress the new information with an already acquired function? Yes, then you've discovered an analogous concept across two different sources. Sort of? Then maybe there's an important difference, or maybe it's a clue that your compression function needs updating. And finally, no? Then perhaps this is an indication that you need to construct a new mental model – a new compression function.

  11. Apr 2020
  12. Jan 2020
  13. Jun 2019
  14. Nov 2018
    1. Rethinking floating point for deep learning


      Facebook人工智能研究院的Jeff Johnson改进了一种新颖的浮点数表示法(posit),使其更加适用于神经网络的训练和推理,并在FPGA上进行了对比实验。和IEEE-754浮点数标准相比,本论文基于改进的浮点数系统,可以实现低bit神经网络训练和高效推理,不再需要后续的量化压缩过程就可以部署在嵌入式等资源受限终端。该论文提出的方法区别于神经网络模型的剪枝、量化等常规思路,直接从浮点数表示这个更加基本、底层的角度尝试解决模型的压缩加速问题,是一个很新颖的方式,且效果不错,值得深入研究。除了论文,作者还给出了代码实现和博客文章,帮助理解。

  15. Oct 2018
  16. Aug 2018
    1. Graph 2 shows the trend for the diastolic pressure.

      Post-exercise, diastolic pressure is higher than baseline; compression garments exaggerate this effect

    2. Graph 1 shows the systolic pressure data (x-axis in mmHg). It can be noted that the test subjects start from an equal baseline condition, but after performing the swimming test the athletes not wearing the costume in the first control (20-30 mins) have an average systolic pressure that has dropped to approximately 90 mmHg.

      Thus, compression garments may prevent circumstantial hypotension. In this case, one possibility is that the compression is delivering blood to the heart that would otherwise be shunted to the skin for heat dissipation.

    1. Major societal transformations are linked to information and communication technologies, giving rise to processes of growing global interdependence. They in turn generate the approxi-mation of coevalness, the illusion of simultaneity by being able to link instantly people and places around the globe. Many other processes are also accelerated. Speed and mobility are thus gaining in momentum, leading in turn to further speeding up processes that interlink the move-ment of people, information, ideas and goods.

      Evokes Virilio theories and social/political critiques on speed/compression, as cited by Adam (2004).

      Also Hassan's work, also cited by Adam (2004).

  17. Jul 2018
    1. Both studies reveal a positive correlation between polychronicity and speed values: The more polychronic the organization, the more doing things rapidly is valued in its culture. Although these consistent findings about the speed-polychronicity relationship support the explanation of the size- polychronicity relationship developed in this discussion, they are not a direct test of this explanation, which is, admittedly, speculative. More direct tests must await studies deliberately designed to investigate this explanation

      Larger firms appear to more polychronic. That finding seems to follow Bluedorn's own speculative findings of a relationship between polychronic organizations and a culture that values speed (time compression).

      Note: Organizational studies of polychronicity have been conducted through quantitative methods (surveys and questionnaires).

    1. This industrial norm, as I suggested above, is fundamen­tally rooted in clock time and underpinned by naturalized assumptions about not just the capacity but also the need to commodify, compress and control time.
    2. In Castells's analysis, time is not merely compressed but processed, and it is the network rather than acceleration that constitutes the discontinuity in a context of continuing compress10n.

      compressed time vs processed time

      acceleration (speed) vs network time

    3. Virilio suggests that we can read the history of modernity as a series of innovations iu ever-increasing time compression. He argues that, through the ages, the wealth and power associated with ownership of land was equally tied to the capacity to traverse it and to the speed at which this could be achieved.

      Cites French political theorist and technology critic Paul Virilio.

      Virilio's engagement with speed integrates 3 concepts that evoke increasing tempos over 3 successive centuries: 19th century transport, 20th century transmission, and 21st century transplantion.

      The concept of transplantation, which is more biological in origin/use, is not as broadly covered here as transport and transmission.

    4. From the above we can see that Virilio understands human history in terms of a race with time, of ever-increasing speeds that transcend humans' biological capacity. To theorize culture without the dromosphere, that is, the sphere of beings in motion, he therefore sugges,ts, misses the key point of cul­tural activity and the uniqueness of the industrial way of life. Without an explicit conceptualization of the contemporary dromosphere -or in my terms timescape -it is thus difficult to fully understand the human-technology-science-economy­equity-environmenr constellation. Moreover, it becomes impossible to appreciate that people are che weakest link when the time frames of action are compressed to zero and effects expand to eternity, when transmission and transplan­tation are instantaneous but their outcomes extend into an open future, when instantaneity and eternity are combined in a discordant fusion of all times.

      Adam's critique of Virilio's incomplete theory on time compression as it related to cultural transformation. Claims it lacks adequate theoretical description/understanding of how people in the high-tempo dromosphere in his writings, (timescape in her work) interact with time.

      Adam further notes how important it is to understand how people factor into discordant time compressions through everyday sociocultural interactions -- which she refers to as "the human-technology-science-economy-equity-environment constellation."

      This is pretty dense theoretical work. Would help to find an example or two in the SBTF time study to make this idea a little more accessible.

    5. the potential capacity of exterrirorial beings to be everywhere at once and nowhere in particular is inescapably tied to operators that are bounded by their embodied temporal limits of terrestrial existence and sequential information processing. The actual capacity for parallel absorption of knowledge, therefore, is hugely disap­pointing. Equally, the electronic capacity to be now-here and no-where has brought the body to a standstill.

      Adam's critique of transmission technologies allowing people to be "now-here and no-where" perhaps also helps unpacks some of the tensions for SBTF's global social coordination.

      Could this be some of the unconscious motive to use terms that situate volunteers with one another as they attempt to grapple with tempo-imposed friction points which work against "terrestrial existence" and "sequential information processing"?

    6. The over­load of information, for example, is becoming so extensive that taking advantage of only the tiniest fraction of it not only blows apart the principle of instantaneity and 'real-time' communication, but also slows down operators to a pomt where they lose themselves in the eternity of electronically networked information.

      High tempo Information overload exacerbates time compression and thus impacts temporal sensemaking through typical means via chronologies, linear information processing, and past/present/future contexts.

    7. The intensive {elec­tronic) present, Virilio suggests, is no longer part of chrono­logical time; we have to conceptualize it instead _as chronoscopic time. Real space, he argues, is making room for decontextualized 'real-time' processes and intensity takes over from extensity.11 This in turn has consequences and, similar to the time compression in transport, the compression in transmission has led to a range of paradoxical effects.

      Definition of chronoscopic time: While still bounded and defined by clock-time, like chronological time, chronoscopic experiences are more tempo-driven and focused on a hyper-present real-time. Chronological time is situated in movement across a timeline of past, present, future where history and temporal story narrative arcs.

      See Purser (2000) for a dromological analysis of Virilio's work on chronoscopic- and real-time.

    8. With respect to twentieth-century transmission Virilio has in mind the wireless telegraph, telephone, radio and subse­quent developments in computer and satellite communica­tion, which have once more changed the relationship between time and movement across space. Together, these innovations in transmission replaced succession and duration with seeming simultaneity and instantaneity. Duration has been compressed to zero and the present extended spatially to encircle the globe: it became a global present.

      In the example of ICT advancements (radio, telegraph, computer, etc.), Adam describes a shift in tempo of a person's temporal experience due to real-time transmission capabilities.

      Tempo experiences that are successive or have some duration quality are transformed into a perceived sense of instantaneous and simultaneous "real time" experience.

      When a sociotemporal experience is lighting up friction points between time and space -- is this where tempo and timelines begin to get entangled?

      Is the computer-mediated "movement" between time and space the inflection point where social coordination begins to break down? That we don't have enough time to process or make sense of CMC-delivered information?

    9. In economic production, time compression has been achieved by a number of means: by increasing the activity within the same unit of tifYle (through machines and the inten­sification of labour), reorganizing the sequence and ordering of activities (Tay!orism and Fordism), using peaks and troughs more effective!�· (flexibilization), and by eliminating all unproductive times from the process ( the just-in-time system of production, delivery and consumption).

      Time compression considers how time moves across space.

      Valorizing speed (aka "time compression" per Marx and CUNY Anthropology and Geography professor David Harvey) is a political and economic goal of Western industrialized nations.

      Speed also provides competitive advantages, whether for technological advancements, cultural movements and species biological evolution.

    10. A third paradox is only hinted at by Vmho, when he suggests that conflict is to be expected between democracy and dromocracy, the politics that take account of time and the speed of movement across space.20 It concerns the sociopolitical and socioeconomic relations associated with advances in transport speed, which affect dif­ferent indivi�uals, groups and classes of society in uneven ways.

      Transportation speed is entangled with social equity and power: time-poor, cash-rich can "buy" time through labor, efficient technologies but the time-rich, cash-poor cannot trade time to become wealthy wealth.

    11. Rifkin and Howard point out, 'the faster we speed up, the faster we degrade

      Virilio writes that speed, or time compression, also contributes to adverse social and environmental impacts, per Rifkin and Howard: "the faster we speed up, the faster we degrade."

    12. In the light of this evidence, which is fully supported by transport research, 17 Virilio formulated the �romological law, which states that increase in speed mcreases the potential for gridlock.

      Virilio's dromological law: "increase in speed, increases the potential for gridlock."

      This evokes environmental concerns as well as critiques of political privilege/power wrt to elites with access to fast transport options and those with less clout relegated to public transportation, traffic jams, less reliable options, etc.

    13. the Reformation had a major role to play in the metamor­phosis of time from God's gift to commodified, comp�essed, colonized and controlled resource. These four Cs of mdus­trial time -comrnodification, compression, colonization and control -will be the focus in these pages, the fifth C of the creation of clock time having been discussed already in the previous chapter. I show their interdependence and id�ntify some of the socio-environmental impacts of those parttcular temporal relations.

      Five C's of industrial time: Commodification, compression, colonialization, control, and clock time.

  18. Feb 2018
    1. Lossless and lossy streaming

      No streaming and no inter-frame compression - along the temporal axis... Just bz2, (google's) snappy and zlib...

      It was far more important to focu s our efforts on compressing the depth data . Developing our own algorithm wa s outside the scope of this project, and existing work on depth data compression is not yet sufficiently developed to implement here, so we decided to work with popular and freely available lossless algorithms implemented in C++. We chose three separate algorithms with different performance characteristics. First, the bzip2 algorithm aims for maximum compression with slower speed. A second algorithm developed by Google, snappy , aim s for maximum speed with less compression. Finally the zlib algorithm aims for a middle ground between speed and compression. To test, we compress ed 500 different depth frames with each algorithm and calculate the mean speed and compression ratio for each.

  19. Sep 2017
  20. Jan 2017
    1. Some cracks are more likely to happen than others, in extension, perpendicular to the force applied is where it will break first ( boof is the breaking sound apparently) in engineering it is most often extension. Geologists work in compression. What happens when you're pushing the original cracks together makes cracks in the vertical orientation will appear as the cracks in the horizontal orientation close.

      How do we know? Milk in glass bottles- glass in refillable bottles but they would break easily and someone wondered why? so they discovered there were microcracks and would make the bottles break easier- not all glass is created equal.

  21. Jan 2014
    1. Difference between XZ and LZMA2 Short answer: xz is a format that (currently) only uses the lzma2 compression algorithm. Long answer: think of xz as a container for the compression data generated by the lzma2 algorithm. We also have this paradigm for video files for example: avi/mkv/mov/mp4/ogv are containers, and xvid/x264/theora are compression algorithms. The confusion is often made because currently, the xz format only supports the lzma2 algorithm (and it’ll remain the default, even if some day, others algorithms may be added). This confusion doesn’t happen with other formats/algorithms, as for example gzip is both a compression algorithm and a format. To be exact, the gzip format only supports to encapsulate data generated by gzip… the compression algorithm. In this article I’ll use “xz” to say “the lzma2 algorithm whose data is being encapsulated by the xz format”. You’ll probably agree it’s way simpler

      The key here is the notion of a format as a container. Lots of content is moving towards that notion-- that a "file" is really an opaque (to the OS filesystem) directory or container of some sort and some other program understands the format of the "file" as a container to know how to open it to access the files inside.