忘れた頃に SRGM の話題。
List of software reliability models - Wikipedia, the free encyclopedia
List of software reliability models - Wikipedia, the free encyclopedia
Software reliability is the probability of the software components of producing incorrect output. Software
should not wear out and continue to operate after a bad result.
Over 225 models have been developed since early 1970s, but how to quantify software reliability still remains
unsolved. There is no single model which can be used in every situation. There is no model which is either
complete or fully developed.
Over 225 models って…
List of software reliability models - Wikipedia, the free encyclopedia
Other Models in software :
Jelinski-Moranda
Goel-Okumoto (exponential)[1]
Rayleigh
Titan Reliability Modeling Software (Predictive)
Weibull
Delayed s-Shaped
Inflexion s-Shaped
この中の Titan Reliability～ ってのは覚えにないな。どんなんだろ。
Tim Cook: Steve Jobs' DNA Will Always Be the Foundation of Apple - Mac Rumors
Tim Cook: Steve Jobs' DNA Will Always Be the Foundation of Apple - Mac Rumors
His thinking and his taste and his incredible perfectionist kind of view, and his view that you should always
innovate, all of those things are alive and well in the company. And I think they always will be. I think his
DNA will always be the foundation of Apple.
向こうでもこういう「DNA」の使い方するんだねえ。
日本に特有のものかと思ってた。
ってなんじゃろか。
それはさておき
Ocean of Awareness
Parsing: a timeline
1960: The ALGOL 60 spec comes out. It specifies, for the first time, a block structured language. The ALGOL
committee is well aware that nobody knows how to parse such a language. But they believe that, if they specify
a block-structured language, a parser for it will be invented. Risky as this approach is, it pays off ...
1961: Ned Irons publishes his ALGOL parser. In fact, the Irons parser is the first parser of any kind to be
described in print. Ned's algorithm is a left parser -- a form of recursive descent. Unlike modern recursive
descent, the Irons algorithm is general and syntax-driven. "General" means it can parse anything
written in BNF. "Syntax-driven" (aka declarative) means that parser is actually created from the BNF
-- the parser does not need to be hand-written.
(略)
1987: Larry Wall introduces Perl 1. Perl embraces complexity like no previous language. Larry uses LALR very
aggressively -- to my knowledge more aggressively than anyone before or since.
(略)
2000: Larry Wall decides on a radical reimplementation of Perl -- Perl 6. Larry does not even consider using LALR again.
(略)
2000 to today: With the retreat from LALR comes a collapse in the prestige of parsing theory. After a half
century, we seem to be back where we started. If you took Ned Iron's original 1961 algorithm, changed the names
and dates, and translated from code from the mix of assembler and ALGOL into Haskell, you would easily
republish it today, and bill it as as revolutionary and new.
Marpa
Over the years, I had come back to Earley's algorithm again and again. Around 2010, I realized that the original,
long-abandoned vision -- an efficient, practical, general and syntax-driven parser -- was now, in fact, quite
possible. The necessary pieces had fallen into place.
以下略
eban さんの
「1から100の整数ただし5つの異なる方法」 - jarp,
これ。
% repeat 1000 { echo $[RANDOM%100+1] } | sort -nu | head -100
(範囲が1から100までの整数である)一様乱数であるとして、1000個で抜けが発生する確率はどのくらいなんだろうか
(0じゃないよね?) と気になったが、計算は面倒くさそうなので考えるのを止めた。
> floor(runif(1000,min=1,max=100))
[1] 51 48 49 43 46 56 79 5 68 56 11 97 55 70 86 32 33 13 94 84 58 94
[23] 88 93 72 74 38 97 87 3 63 79 33 64 40 30 22 23 43 22 6 39 47 72
[45] 2 59 77 84 82 74 41 72 55 73 93 74 19 40 79 65 31 96 21 2 86 16
[67] 33 50 26 26 66 13 22 41 12 21 93 13 49 31 26 23 62 40 96 61 66 57
[89] 24 89 87 99 56 58 17 94 85 19 27 58 84 7 6 85 20 11 60 97 3 77
[111] 50 66 8 76 4 64 11 48 86 38 40 19 57 20 10 2 50 63 93 59 34 92
[133] 20 44 89 80 98 94 42 24 86 25 61 49 6 23 50 25 13 86 13 69 25 9
[155] 19 1 66 16 27 81 96 18 96 67 95 97 24 66 19 76 40 65 75 5 87 69
[177] 51 65 92 51 16 95 41 19 58 52 48 61 14 66 86 72 89 60 73 39 70 70
[199] 8 85 5 82 49 64 93 36 72 4 94 82 35 16 86 3 37 8 18 86 25 86
[221] 29 4 11 2 8 53 90 24 98 12 66 5 71 42 13 99 83 29 14 8 77 31
[243] 9 50 14 3 28 68 94 7 18 19 51 3 28 28 55 69 70 79 21 7 96 70
[265] 67 14 98 74 40 79 97 89 59 79 48 32 8 14 2 76 50 91 76 13 98 78
[287] 32 1 53 71 41 13 24 72 63 75 36 64 4 61 38 73 24 61 89 66 39 74
[309] 57 9 73 89 65 30 91 63 2 85 39 37 46 85 84 58 48 46 40 99 53 69
[331] 95 71 67 78 74 24 9 51 81 37 88 54 68 10 30 90 54 93 98 58 13 23
[353] 53 17 4 56 99 11 56 83 44 50 96 52 77 71 1 57 94 44 94 79 97 93
[375] 71 31 42 18 44 40 91 59 91 28 18 55 78 35 25 24 66 21 45 52 33 56
[397] 3 41 53 95 55 46 85 99 16 56 4 61 10 24 14 28 1 87 61 24 41 66
[419] 4 4 85 61 77 11 38 46 18 7 13 90 51 39 35 84 15 65 21 41 19 15
[441] 9 66 96 8 55 27 27 83 67 94 97 21 51 38 77 68 82 88 32 88 65 46
[463] 39 66 94 94 85 46 10 86 8 30 74 7 15 51 77 53 92 31 15 2 64 15
[485] 3 13 11 85 29 72 96 52 94 84 35 51 4 54 22 53 48 42 24 85 20 77
[507] 27 80 23 1 9 20 81 98 86 22 95 67 91 37 88 26 22 72 5 67 41 49
[529] 98 17 15 29 70 93 39 65 36 33 76 25 59 62 78 22 98 5 95 71 79 75
[551] 78 54 76 45 77 21 84 20 34 40 74 86 69 97 45 94 63 80 8 45 53 66
[573] 53 14 74 86 11 47 69 64 22 51 47 4 12 98 27 27 64 32 36 52 72 21
[595] 41 43 50 62 16 58 46 82 2 44 22 44 46 59 68 99 63 68 88 16 93 99
[617] 21 11 36 53 61 10 48 88 89 89 72 72 81 16 58 20 24 9 56 20 53 55
[639] 4 2 73 35 26 7 60 14 43 72 65 97 4 37 27 20 37 77 59 95 53 9
[661] 19 3 89 91 29 18 31 22 45 43 16 35 28 50 36 89 43 26 90 54 43 32
[683] 68 82 77 83 49 52 75 35 72 7 59 78 52 58 65 10 74 14 59 55 52 94
[705] 13 82 92 17 1 95 36 1 67 54 39 4 95 46 67 61 35 15 1 46 92 49
[727] 82 21 76 60 39 38 9 22 6 87 82 11 3 1 98 10 36 2 20 42 99 91
[749] 46 92 70 5 76 36 75 90 21 96 40 30 64 65 65 14 44 75 2 27 27 57
[771] 75 83 41 69 10 55 35 92 75 14 34 90 86 6 14 97 6 37 14 8 98 46
[793] 57 44 48 82 39 8 13 26 7 42 3 21 7 97 13 8 59 95 55 17 7 37
[815] 43 92 76 86 77 28 11 79 74 55 41 88 48 30 17 45 83 25 12 45 80 80
[837] 31 2 82 93 29 91 66 15 56 97 66 21 72 40 88 7 73 22 28 15 67 55
[859] 21 49 55 30 36 15 12 85 62 24 40 34 13 75 27 84 83 50 60 60 98 14
[881] 22 37 6 4 20 79 36 97 79 13 62 14 36 43 71 71 56 67 67 52 70 69
[903] 36 47 71 81 70 69 28 98 93 48 36 14 75 43 37 24 45 21 95 42 41 11
[925] 78 96 79 93 19 87 93 10 59 31 3 14 7 3 93 61 14 11 28 24 49 72
[947] 97 73 76 84 69 53 96 3 95 97 75 31 84 19 79 81 12 44 70 17 23 55
[969] 13 61 57 5 5 55 73 43 12 93 99 32 30 74 21 64 45 99 66 24 91 14
[991] 68 81 86 4 53 44 67 25 12 85
> unique(sort(floor(runif(1000,min=1,max=100))))
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
[24] 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
[47] 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
[70] 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92
[93] 93 94 95 96 97 98 99
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
> length(unique(sort(floor(runif(1000,min=1,max=101)))))
[1] 100
