I used this set of slides for a lecture I gave for the PhD students from the University of Lugano on how to do research.

1. Yogi Berra
You’ve got to be careful
if you do not know
where you are going,
because you might not get there.

2. demo-
driven
research
www.tudorgirba.com

3. demo-
driven
research
www.tudorgirba.com
challenge
design
demo
listen
enable

4. research?

5. research improves
the status quo

6. the status quo?

7. the status quo
the existing state of affairs

8. Picture by _FXR

9. Picture by _FXR

10. Picture by _FXR
F = m a.

11. E = m c. 2
Picture by _FXR

12. post-it

14. the status quo
the existing state of affairs

15. the status quo
the sum of our assumptions

16. Tom de Marco
It’s not what you don’t know that kills you,
it’s what you know that isn’t so

18. the status quo
the sum of our assumptions

19. research
revealing what no one revealed before

20. demo-
driven
research
www.tudorgirba.com
challenge

21. demo-
driven
research
www.tudorgirba.com
challenge
design

30. demo-
driven
research
www.tudorgirba.com
challenge
design

31. demo-
driven
research
www.tudorgirba.com
challenge
design
present

34. to Understand Software Evolution
Modeling History
vorgelegt von
Tudor Gîrba
von Rumänien
Inauguraldissertation der
Philosophisch-naturwissenschaftlichen
Fakultät der Universität Bern
Leiter der Arbeit:
Prof. Dr. Stéphane Ducasse
Prof. Dr. Oscar Nierstrasz
Institut für Informatik und
angewandte Mathematik

35. To provide a generic
meta-model for
expressing software
evolution analyses,
we need to recognize
evolution as an explicit
phenomenon and model
it as a first class entity.
to Understand Software Evolution
Modeling History
vorgelegt von
Tudor Gîrba
von Rumänien
Inauguraldissertation der
Philosophisch-naturwissenschaftlichen
Fakultät der Universität Bern
Leiter der Arbeit:
Prof. Dr. Stéphane Ducasse
Prof. Dr. Oscar Nierstrasz
Institut für Informatik und
angewandte Mathematik

40. tudorgirba.com/blog
blog.duarte.com
thebackofthenapkin.com

41. www.ted.com

43. content

44. content form

45. content form

46. content form

47. yesterday’s
weather

49. 30%

50. 30% 90%

51. yesterdayWeatherProbabilityWithTopPreviousWENM: topPreviousWENM
andTopCurrentENM: topCurrentENM
| currentVersions previousClassHistoriesSortedByWENM
yesterdayWeatherHits last2VersionsTopHistories last2Versions
last2HistoriesSortedByENM x valuesCount previousVersionsTopHistories
previousVersionsTopHistoriesNames over |
currentVersions := OrderedCollection new.
currentVersions addLast: (self allVersionNames at: 1).
yesterdayWeatherHits := 0.
(2 to: self allVersionNames size) do: [: i |
self smelly: 'this algorithm is too big and complex'.
previousClassHistoriesSortedByWENM := (self classHistories
selectFromReferenceVersionCollection: currentVersions)
sortBy: [:a :b | a value getWENM >= b value getWENM].
currentVersions addLast: (self allVersionNames at: i).
previousVersionsTopHistories := OrderedCollection new.
x := previousClassHistoriesSortedByWENM first value getWENM.
valuesCount := 0.
previousClassHistoriesSortedByWENM do: [ :each |
(each value getWENM ~= x) ifTrue: [
valuesCount := valuesCount + 1. x:= each value getWENM].
(valuesCount < topPreviousWENM) ifTrue: [
previousVersionsTopHistories addLast: each]
].
last2VersionsTopHistories := OrderedCollection new.
last2Versions := OrderedCollection new.
last2Versions addLast: (self allVersionNames at: (i-1)).
last2Versions addLast: (self allVersionNames at: i).

52. valuesCount := valuesCount + 1. x:= each value getWENM].
(valuesCount < topPreviousWENM) ifTrue: [
previousVersionsTopHistories addLast: each]
].
last2VersionsTopHistories := OrderedCollection new.
last2Versions := OrderedCollection new.
last2Versions addLast: (self allVersionNames at: (i-1)).
last2Versions addLast: (self allVersionNames at: i).
last2HistoriesSortedByENM := (self classHistories
selectFromReferenceVersionCollection: last2Versions)
sortBy: [:a :b | a value getWENM >= b value getWENM].
x := last2HistoriesSortedByENM first value getENM.
valuesCount := 0.
last2HistoriesSortedByENM do: [ :each |
(each value getENM ~= x) ifTrue: [
valuesCount := valuesCount + 1. x:= each value getENM].
(valuesCount < topCurrentENM) ifTrue: [
last2VersionsTopHistories addLast: each]
].
previousVersionsTopHistoriesNames := previousVersionsTopHistories
collect: [ :each | each value name].
over := false.
last2VersionsTopHistories do: [:each |
((previousVersionsTopHistoriesNames includes: (each value name))
and: [over not]) ifTrue: [
yesterdayWeatherHits := yesterdayWeatherHits + 1. over := true].
].
].
^yesterdayWeatherHits/(self size - 1) asFloat.

53. yesterdayWeatherProbabilityWithTopPreviousWENM: topPreviousWENM
andTopCurrentENM: topCurrentENM
| currentVersions previousClassHistoriesSortedByWENM
yesterdayWeatherHits last2VersionsTopHistories last2Versions
last2HistoriesSortedByENM x valuesCount previousVersionsTopHistories
previousVersionsTopHistoriesNames over |
currentVersions := OrderedCollection new.
currentVersions addLast: (self allVersionNames at: 1).
yesterdayWeatherHits := 0.
(2 to: self allVersionNames size) do: [: i |
self smelly: 'this algorithm is too big and complex'.
previousClassHistoriesSortedByWENM := (self classHistories
selectFromReferenceVersionCollection: currentVersions)
sortBy: [:a :b | a value getWENM >= b value getWENM].
currentVersions addLast: (self allVersionNames at: i).
previousVersionsTopHistories := OrderedCollection new.
x := previousClassHistoriesSortedByWENM first value getWENM.
valuesCount := 0.
previousClassHistoriesSortedByWENM do: [ :each |
(each value getWENM ~= x) ifTrue: [
valuesCount := valuesCount + 1. x:= each value getWENM].
(valuesCount < topPreviousWENM) ifTrue: [
previousVersionsTopHistories addLast: each]
].
last2VersionsTopHistories := OrderedCollection new.
last2Versions := OrderedCollection new.
last2Versions addLast: (self allVersionNames at: (i-1)).
last2Versions addLast: (self allVersionNames at: i).

54. yesterdayWeatherProbabilityWithTopPreviousWENM: topPreviousWENM
andTopCurrentENM: topCurrentENM
| currentVersions previousClassHistoriesSortedByWENM
yesterdayWeatherHits last2VersionsTopHistories last2Versions
last2HistoriesSortedByENM x valuesCount previousVersionsTopHistories
previousVersionsTopHistoriesNames over |
currentVersions := OrderedCollection new.
currentVersions addLast: (self allVersionNames at: 1).
yesterdayWeatherHits := 0.
(2 to: self allVersionNames size) do: [: i |
self smelly: 'this algorithm is too big and complex'.
previousClassHistoriesSortedByWENM := (self classHistories
selectFromReferenceVersionCollection: currentVersions)
sortBy: [:a :b | a value getWENM >= b value getWENM].
currentVersions addLast: (self allVersionNames at: i).
previousVersionsTopHistories := OrderedCollection new.
x := previousClassHistoriesSortedByWENM first value getWENM.
valuesCount := 0.
previousClassHistoriesSortedByWENM do: [ :each |
(each value getWENM ~= x) ifTrue: [
valuesCount := valuesCount + 1. x:= each value getWENM].
(valuesCount < topPreviousWENM) ifTrue: [
previousVersionsTopHistories addLast: each]
].
last2VersionsTopHistories := OrderedCollection new.
last2Versions := OrderedCollection new.
last2Versions addLast: (self allVersionNames at: (i-1)).
last2Versions addLast: (self allVersionNames at: i).

57. present

58. present
past

59. present
past future

60. present
past future

61. present
past future

62. present
past future
prediction hit

63. present
past future
YesterdayWeatherHit(present):
past:=all.topChanged(beginning, present)
future:=all.topChanged(present, end)
past.intersect(future).notEmpty()
prediction hit

64. hit hit hit
YW = 3 / 8 = 37%
hit hit hit hit hit hit hit
YW = 7 / 8 = 87%

65. yWFor: yesterdayCheck for: tomorrowCheck
| hits |
hits := (self detailedYWFor: yesterdayCheck for: tomorrowCheck)
sum: [ :each | each isEmpty ifTrue: [0] ifFalse: [1]].
^ hits / (self versions size - 2)
yWFor: yesterdayCheck for: tomorrowCheck
^ ( 3 to: self versions size ) collect: [ :i |
| yesterday tomorrow |
yesterday := self
selectByExpression: yesterdayCheck
appliedFromVersionIndex: 1
toVersionIndexAndPresentInIt: i - 1.
tomorrow := self
selectByExpression: tomorrowCheck
appliedFromVersionIndexAndPresentInIt: i - 1
toVersionIndex: self versions size.
yesterday intersectWith: tomorrow ]

66. content form

69. content form

70. demo-
driven
research
www.tudorgirba.com
challenge
design
present

71. demo-
driven
research
www.tudorgirba.com
challenge
design
demo

73. demo-
driven
research
www.tudorgirba.com
challenge
design
demo

74. demo-
driven
research
www.tudorgirba.com
challenge
design
demo
listen

75. Reviewers are never stupid

76. demo-
driven
research
www.tudorgirba.com
challenge
design
demo
listen

77. demo-
driven
research
www.tudorgirba.com
challenge
design
demo
listen
enable

79. it’s not Lupus

81. established

82. established

83. disruptive
established

84. What
Where
When
Who
How

85. What
Where
When
Who
How Why

86. demo-
driven
research
www.tudorgirba.com
challenge
design
demo
listen
enable

87. Tudor Gîrba
www.tudorgirba.com
creativecommons.org/licenses/by/3.0/