Recent submissions

Comment · 6 years ago
Comment · 7 years ago
I've been following data Artisans for a while and love their tech! It seemed that being not from silicon valley made it more difficult for them to gain traction.

One part of the acquisition is the integration of Alibaba's in-house modifications called Blink. It will be interesting to see what is behind that. To me it looks like this could be a very health collaboration.

Comment · 11 years ago
Damn these numbers! :D

Regarding your correction. The percent value is now too low (.002%). I think you used the factor value of ~0.002 as percentage. So you probably meant 0.2% which would be close to my number.

Using your numbers

30000/18200000 = .00164835164835164835 = ~0.16% = ~0.2%

Comment · 11 years ago
I think you are mixing the number up. I could not find a source that said anything close to the 1.7 million metric tons per day emitted by the leaking well you used for your calculation.

The leak is emitting 1247 metric tons of CO2e per hour that is 29928 metric tons of CO2e per day. So its 0.17% instead of 9% of nation-wide emissions.

Comment · 11 years ago
I corrected my calculation (using the correct 25 factor for metric tons). Thanks for the hint!
Comment · 11 years ago
I corrected the analysis, thanks for the clue, this paints a completely different picture. I corrected the analysis
Comment · 11 years ago
On the topic of what went wrong I think this LA weekly[3] article is a much better source. The main problem why the well can't be shut down is that the security valve was removed about 40 years ago: "He pointed out that the valve was old at that time and leaking. It also was not easy to find a new part, so the company opted not to replace it.". Certainly a bad decision and it should be checked if regulations need to be changed to avoid similar problems in the future.

EDIT: The old version had used the wrong conversion factors, now corrected

The central number is the exhaust mass of 110,000 pounds per hour. So how much is this really? This is about 50 metric tons of methane per hour. To be able to compare it with other greenhouse emissions we can calculate the CO2 equivalent by multiplying with 0.01133[1] giving the rate of: 1247 metric tons CO2e per hour.

Using the EPA Online tool[2] we can relate this to the toal emissions in Calfornia or the US. The total emission of methan measured in CO2e for California in 2014 was: 9,546,270 metric tons CO2e. Converted to a rate per hour this gives: 1089 metric tons CO2e per hour.

So while the well is leaking it is releasing 114% of the normal methane emissions of California.

Compared to all greenhouse gas emissions the well is causing an increase of 10% in california and 0.3%at the US national level compared to the emissions from large facilities.

[1] http://www3.epa.gov/gasstar/tools/calculations.html

[2] http://ghgdata.epa.gov/ghgp/main.do

[3] http://www.laweekly.com/news/what-went-wrong-at-porter-ranch...

Comment · 11 years ago
It does not really compare, I guess thats also why its not mentioned.

The whole premise of the paper is that data can be analyzed in situ. That means loading from its original place in the original format without any previous transformations. This is in contrast to the traditional approach of database systems that the data has to be loaded first into a database.

This paper describes a way how unprocessed unindexed data can be efficiently used to answer queries using a database system. The novelty of this approach is mostly that they build a index on the fly that can be reused later and examining the idea of directly using the raw files. For efficient loading of CSV files which is also mentioned in the NoDB paper, I think those details are better described in a later paper from TU München[1] that examines this aspect in more detail.

HDT for RDF or Parquet[2] and ORCFiles[3] in the Big Data space, are (binary) formats where the data is already processed and stored in a more efficient format than plain old text CSV files. Creating these files can already be compared to just loading the data into a database. The only difference that format used for data storage is open and can be used by many systems. So its a completely different setting.

Still its an interesting thought to make databases aware of the indexed information in those file formats besides CSV so that these can also be directly used without loading.

[1] http://www.vldb.org/pvldb/vol6/p1702-muehlbauer.pdf

[2] https://github.com/Parquet/parquet-format

[3] https://cwiki.apache.org/confluence/display/Hive/LanguageMan...

Comment · 11 years ago
The article lacks a description of which specific form of pollution is compared.

When talking about pollutants is important to keeps the following points in mind:

- Is the pollutant effecting health?

- Is the pollutant effecting climate change?

- Is the amount of pollution locally concentrated or very distributed?

Cargo ships typically have a very high emission of nitrogen Oxides (NOx) and sulphur dioxide. When emitted by cars / factories on the mainland these often strongly contribute to harmful smog especially in megacities or cities with poor ventilation. Also they can be generally bad to the ecosystem also on the water due to causing acid rain etc.

The main pollutants on cargo ships have a very strong short term effect but are often out of the air in a few weeks. Because of that they don't rise to the atmosphere and don't directly contribute to long term climate changes. Thus I think the comparison in the article is very dangerous. When considering pollutants that effect climate change cars are more dominant.

So depending on which effects are discussed reducing pollutions from cars can still be benefitial. As an additional thought, the polutions of the cargo ships are spread out over a very large geographich area while the exhausts of cars are much more concentrated around cities. So when considering ones own quality of living, cars have a much bigger impact.

I think an article that better manages to discuss the subject is this one from the guardian: http://www.theguardian.com/environment/2009/apr/09/shipping-...

Excerpts:

- Shipping is responsible for 18-30% of all the world's nitrogen oxide (NOx) pollution and 9% of the global sulphur oxide (SOx) pollution.

- Shipping is responsible for 3.5% to 4% of all climate change emissions

Comment · 11 years ago
For x264 that is true, HEVC which is also mentioned is much slower. For a 4k source transcoding can take more than a second per frame. For a normal movie this can quickly result in encoding times of more than a day.

Another problem is that you have to encode the movie for each codec profile times the number of different bitrates per profile. The article mentions four profiles (VC1, H.264/AVC Baseline, H.264/AVC Main and HEVC) and bitrates ranging from 100 kbps to 16 Mbps. Assuming now there are 20 different bitrates per code you already get 4*20 => 80 encoded copies per source. But of course this can be solved by parallelism.

Comment · 11 years ago
I just did this page. The page is indexed. When I look for the search term "Update this was posted to Google on Friday the 17th of July, 2015. Monday, the 20th" the page is shown.

Trying to find any of the other search strings in the article for the different loading variants does not return any results. So no variant of javascript injected content is working on Bing currently.

Comment · 11 years ago
I like to use -Wpedantic for my own projects to keep the code clean and it helped my well. Its not included in -Wall and -Wextra.

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