The document discusses type systems and their purposes. It makes three key points:
1. Type systems are designed to prevent programs from having execution errors or going wrong. Well-typed programs are less likely to crash or diverge from their intended behavior.
2. There are two main kinds of typing: static typing checks types at compile-time while dynamic typing checks types at run-time. Both exist because it is impossible to design a type system that rejects all incorrect programs while accepting all correct ones.
3. Type systems can be specified formally using type rules, judgements, and environments to define the valid operations between types. This provides a way to precisely define how a program's types are checked.
Image understanding and artificial intelligenceI MT
Thèse "Image understanding and artificial intelligence" par Isabelle BLOCH, lors de la journée Futur & Ruptures du 31 janvier 2019. Une journée scientifique pour présenter l’ensemble des travaux de thèses aboutis portant sur des thématiques prospectives du programme de l’IMT.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
Image understanding and artificial intelligenceI MT
Thèse "Image understanding and artificial intelligence" par Isabelle BLOCH, lors de la journée Futur & Ruptures du 31 janvier 2019. Une journée scientifique pour présenter l’ensemble des travaux de thèses aboutis portant sur des thématiques prospectives du programme de l’IMT.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
2. Typing
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 2 / 30
3. The Purpose of Typing
”Well-typed programs never go wrong.”
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 3 / 30
4. What Does ”Go Wrong” Entail?
Execution errors.
Program crash.
Divergence.
...
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 4 / 30
5. The Purpose of Typing (II)
As a side effect, typed programs are also more likely to actually do what
they are supposed to do.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 5 / 30
6. Two Kinds of Typing
Static typing.
Dynamic typing (more precisely: dynamic checking).
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 6 / 30
7. Why Do They Both Exist?
It is provenly impossible to create a type system that rejects all
incorrect programs (written in a real-world programming language)
and accepts all correct ones.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 7 / 30
8. Why Do They Both Exist?
It is provenly impossible to create a type system that rejects all
incorrect programs (written in a real-world programming language)
and accepts all correct ones.
Benefits vs. costs trade-off: static typing rejects at least some
incorrect programs at the expense of not accepting certain correct
ones.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 7 / 30
9. Example
class Foo { public void urgh() { ...} }
class Bar { public void urgh() { ...} }
void main() {
Object var;
if ( something()) var = new Foo();
else var = new Bar();
var.urgh();
}
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 8 / 30
10. Example
class Foo { public void urgh() { ...} }
class Bar { public void urgh() { ...} }
void main() {
Object var;
if ( something()) var = new Foo();
else var = new Bar();
var.urgh();
}
It is obvious that an object pointed at by var has method urgh, however,
many type systems don’t provide any way of expressing it without
modifying (and recompiling) definitions of Foo and Bar.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 8 / 30
11. Which Is Better?
Debating which is better may (and probably will) get you into a
violent flamewar.
The real question is whether there will ever be a type system that does
not stand in programmers’ way and rejects all incorrect programs.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 9 / 30
12. Relaxed Notions of Typing
Untrapped errors vs. trapped errors, forbidden errors.
Safe languages disallow untrapped errors (usually by a mixture of
static and runtime checks).
Strongly typed languages disallow forbidden errors (ditto).
Weakly typed languages allow even for untrapped errors.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 10 / 30
13. Type Algebra
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 11 / 30
14. Function Type
A→B
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 12 / 30
15. Product Type
A×B
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 13 / 30
16. Intersection Type
A∩B
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 14 / 30
17. Union Type
A∪B
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 15 / 30
18. Type System
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 16 / 30
19. Two Components of Type Control
Type system—a specification.
Type checking algorithm—an algorithm.
There may be zero or more than one distinct type checking
algorithms for a particular type system.
Type systems described in a formal language have lower
probability of ambiguities, unconsidered corner cases etc.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 17 / 30
20. Example
begin
string s;
s = "abc";
string t;
t = s + "def";
end
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 18 / 30
21. Grammar
P → begin CL end program
CL → C ; CL sequential composition
C→T I declaration
I =E assignment
T → string types
int
E→I identifier
N numeral
S string literal
E1 + E2 sum of two subexpressions
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 19 / 30
22. Key Components of a Type System Specification
Judgements.
Type rules.
Environment.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 20 / 30
23. Type System
Empty Environment
∅ ◦
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 21 / 30
24. Type System (II)
Variable Creation
I : string ∈ Γ I : int ∈ Γ Γ ◦
Γ ∪ {I : string } ◦ Γ ∪ {I : int} ◦
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 22 / 30
25. Type System (III)
Literals
Γ ◦ Γ ◦
Γ S : string Γ N : int
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 23 / 30
26. Type System (IV)
Variables in Environment
I : string ∈ Γ I : int ∈ Γ
Γ I : string Γ I : int
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 24 / 30
27. Type System (V)
Sum
Γ E : string Γ F : string Γ E : int Γ F : int
Γ E + F : string Γ E + F : int
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 25 / 30
28. Type System (VI)
Assignment
Γ I : string Γ E : string Γ I : int Γ E : int
Γ I =E : Γ I =E :
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 26 / 30
29. Type System (VII)
Sequential Composition
Γ ◦
Γ :
Γ ∪ {I : string } ◦ Γ ∪ {I : string } C:
Γ string I ; C :
Γ ∪ {I : int} ◦ Γ ∪ {I : int} C:
Γ int I ; C :
Γ C: Γ CL :
Γ C ; CL :
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 27 / 30
30. Type System (VIII)
Program
∅ CL :
begin CL end :
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 28 / 30
31. Other Uses of Type Information
Semantics.
Optimization.
Static analysis.
...
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 29 / 30
32. See
Luca Cardelli. Type Systems. ACM Computing Surveys 28, 1 (March
1996), 263-264. http://doi.acm.org/10.1145/234313.234418
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 1: Type Systems September 21, 2010 30 / 30