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Re-Exam

Written on 13.03.23 by Sophie Wenning

Dear Students,

as promised further details on the oral re-exam:

Duration: 30-40 min
Date: a chosen time slot between March 27 and March 29
Topic: a chapter of your choice, the first and last one being excluded as in the main exam.
Structure: In the first 15 min of the exam, we will test… Read more

Dear Students,

as promised further details on the oral re-exam:

Duration: 30-40 min
Date: a chosen time slot between March 27 and March 29
Topic: a chapter of your choice, the first and last one being excluded as in the main exam.
Structure: In the first 15 min of the exam, we will test your knowledge of the key definitions, core results and proof outlines of the chapter you pre-selected. In the remaining 15 min, we will ask more general questions challenging your general understanding of the chapter and its connections to other topics and results presented in the course.

If you would like to take the re-exam, please send me an email answering the following questions as soon as possible!

Date: please name all slots in which you're available from Monday 27.03 to Wednesday 29.03 from 09:00 a.m to 04:00 p.m (or those in which you're not available if that's shorter).
Chapter: please let us know to which chapter should be topic of your exam.

Best,

Sophie

Exam and Final Grades

Written on 11.03.23 by Sophie Wenning

Dear Students,

we've graded the exam. A detailed feedback is available in the CMS alongside your submission. We also informed you about your final grade by mail. Since so many of you had trouble solving the exam questions, we decided to offer an oral re-exam. Further details will be clarified… Read more

Dear Students,

Best,

Sophie

New Clarifications available!

Written on 27.02.23 by Sophie Wenning

Dear Students,

some new clarifications on exam question 1 and 3 are now available in the materials section!

Best,

Sophie

Clarifications Exam

Written on 24.02.23 by Sophie Wenning

Dear Students,

we decided to make all questions (and their answers!) you've mailed us asking for clarifications of exam questions available in the materials section. We will inform you whenever a new version with further questions and answers is available.

Best,

Sophie

Final Exam

Written on 24.02.23 by Sophie Wenning

Dear Students,

as agreed, the final exam will be released today at noon. Please submit your solution to the CMS by Friday, 03.03.2023 12:00. If you have questions, write us an email.

Good Luck!

Sophie

Schedule for Q&A session and exam

Written on 06.02.23 by Sophie Wenning

Dear Students,

as discussed in the last lecture today, we will have a Q&A session on Monday, 20.02.2023, 10 a.m. Also, as agreed upon earlier, the one-week take-home exam will cover chapter 5,6 & 7. It will be handed out on Friday, 24.02.2023; the respective submission is due by Friday, 03.03.2023.… Read more

Dear Students,

Best,

Sophie

Reminder: Exam Registration

Written on 01.02.23 by Sophie Wenning

Dear Students,

please remember to register yourself in the LSF/HISPOS by Wednesday, 08.02.2023, 23:59 if you would like to take the exam.

Best,

Sophie

Ninth Assignment

Written on 25.01.23 by Sophie Wenning

Dear Students,

the last book chapter covered this semester is online now. Please submit your summary by Wednesday, 01.02.2023, 10:00 a.m.

Best,

Sophie

Eight Assignment

Written on 18.01.23 by Sophie Wenning

Dear Students,

the book chapter on Synchronous Counting is online now. Please submit your summary by next Wednesday, 25.01.2023, 10:00 a.m.

Best,

Sophie

No lecture on Monday

Written on 07.01.23 by Sophie Wenning

Dear Students,

Unfortunately we have to cancel this Monday's (09.01) lecture.

Best,

Sophie

Seventh Chapter

Written on 04.01.23 by Sophie Wenning

Dear Students,

the book chapter on Self-Stabilising Pulse Synchronisation is online now. The corresponding summary is due on Wednesday, 11.01.2023 10:00 a.m.

Best,

Sophie

Sixth Assignment

Written on 22.12.22 by Sophie Wenning

Dear students,

the seventh chapter is online now. The corresponding summary is due by Monday, 02.01.2023 10:00 a.m.

Merry Christmas & a happy New Year!

Best,

Sophie

Fifth Assignment

Written on 07.12.22 (last change on 07.12.22) by Sophie Wenning

Dear Students,

the rather short sixth chapter on a self-stabilising version of the Lynch-Welch algorithm is online now. The corresponding summary is due on Wednesday, 14.12.2022, 10:00 a.m.

Best,

Sophie

Fourth Assignment

Written on 29.11.22 by Sophie Wenning

Dear students,

the fifth book chapter is available in the materials section. Please submit your summary by Monday, 05.12, 10:00 a.m.

Best,

Sophie

Third Assignment

Written on 16.11.22 by Sophie Wenning

Dear Students,

the chapter on low-degree clock distribution networks is now available in the materials section. Please submit your summary by Wednesday, 23.11, 10:00 a.m.

Best,

Sophie

Sample Summary

Written on 14.11.22 by Sophie Wenning

Dear Students,

I uploaded a sample summary of chapter 9, written by a student, which meets what we expect of an excellent submission.

Best,

Sophie

Second Assignment

Written on 08.11.22 (last change on 08.11.22) by Sophie Wenning

Dear Students,

the third book chapter "Synchronising by Approximate Agreement" is available in the materials section. Please submit your summary on your personal CMS status page by Wednesday, 16.11, 10:00 a.m.

Best,

Sophie

Clarifications

Written on 30.10.22 by Sophie Wenning

Dear Students,

the definitions missing in Chapter 9 are now available in a separate document in the materials section. Many thanks to the person who pointed out this incompleteness!

Apologies and best regards,

Sophie

Model Chapter

Written on 26.10.22 by Sophie Wenning

Dear Students,

please take note that I accidentally published the wrong chapter 1 (Models) so please make sure to read the correct updated one!

Best,

Sophie

Reading Material & First Summary

Written on 26.10.22 by Sophie Wenning

Dear Students,

the introductory chapter on models is now available in the materials section. You don't need to write a summary of this specific chapter but please read it before the lecture Monday morning.

The first mandatory assignment consists in writing a summary of Chapter 2 - Limits of… Read more

Dear Students,

the introductory chapter on models is now available in the materials section. You don't need to write a summary of this specific chapter but please read it before the lecture Monday morning.

The first mandatory assignment consists in writing a summary of Chapter 2 - Limits of Fault Tolerance. As mentioned earlier, I uploaded a guide on how to write a good summary in the materials section. It is due by Wednesday 02.11, 10:00 a.m.

Feel free to ask questions (by mail!) if there is something unclear!

Best,

Sophie

First lecture

Written on 25.10.22 by Sophie Wenning

Dear Students,

the Zoom link is available in the materials section.

See you tomorrow!

Sophie

Show all

Clock Synchronization and Adversarial Fault Tolerance

People

Lecturers:

Christoph Lenzen
Danny Dolev

Teaching Assistant:

Sophie Wenning

Lecture slots

Weekly lecture slots:

Monday, 10-12
Wednesday, 10-12

First lecture:

Wednesday, 26.10

There are no tutorials. The lectures are online. The participation link will be sent out to registered students before the first lecture (later registrations are possible; please contact Christoph Lenzen (mail) or Sophie Wenning (mail) for receiving the link in this case).

Content overview

This course takes a close look at how clock synchronization can be achieved in spite of transient and permanent faults, i.e., what happens when one or more clock domains behave in unexpected or even malicious ways. It explores fault-tolerant clock distribution protocols, self-stabilising synchronisation algorithms as well as some fundamental limitations resulting from faults. All topics will be first studied through the lense of mathematical proofs. However, as the presented algorithms are simple and practical enough to be implemented on physical chips, we also will investigate real-world constraints arising from hardware and the unforgiving need for efficiency. Based on these observations, we will build bridges back to the theoretical level and try to adapt and improve our models.

Classroom model

This lecture follows the inverted classroom model. This implies that the course is structured as follows:

We will provide you with some reading material one week before each new lecture block and you will prepare a summary of the topic which we will grade. You are also encouraged to ask questions about aspects that you feel you have not yet properly understood. This step is intended to prepare you for the actual lecture.
The lecture itself aims to be interactive. The lecturers will present the topic in more detail. In a subsequent discussion we will answer your questions before moving on to jointly solved exercises designed to further deepen your understanding of the topic.

Prerequisites

No prerequisites beyond basic familiarity with mathematical reasoning are required. It can be helpful to have knowledge about (electric) circuitry and Boolean logic, but this is not mandatory. Note in particular that last semester's course "How to clock your computer" is NOT a prerequisite.

Evaluation

The grades for this course will be computed from:

Homework assignments (25%): you have to write a short summary for each of the above chapters. These fortnightly assignments will be graded.
Participation in class (25%): we appreciate your participation in the discussions that will form an important part of each lecture. As your contribution will be graded, attendance at the lectures is strongly recommended.
Final written submission (50%): a final homework assignment at the end of the semester completes the assessment.