Lic. Thesis Seminar: Integration of Clouds to Industrial Communication Networks

Publicerad: 2020-12-16

Title: Integration of Clouds to Industrial Communication Networks

Presenter: Haorui Peng, Electrical and Information Technology, LTH, Lund University and Wallenberg AI, Autonomous Systems and Software Program (WASP)

Reviewer: Prof. Åke Arvidsson från Kristianstad University

Examiner: Christian Nyberg, Electrical and Information Technology, LTH, Lund University

When: 29 January 2021 at 13.15

Location: Online at the zoom platform. Please register at https://www.lth.se/digitalth/events/register-2021-01-29/ in order to get an access link.

Abstract

Cloud computing, owing to its ubiquitousness, scalability and on-demand ac- cess, has transformed into many traditional sectors, such as telecommunication and manufacturing production. As the Fifth Generation Wireless Specifications (5G) emerges, the demand on ubiquitous and re-configurable computing resources for handling tremendous traffic from omnipresent mobile devices has been put forward. And therein lies the adaption of cloud-native model in service delivery of telecommunication networks. However, it takes phased approaches to successfully transform the traditional Telco infrastructure to a softwarized model, especially for Radio Access Networks (RANs), which, as of now, mostly relies on purpose-built Digital Signal Processors (DSPs) for computing and processing tasks.

On the other hand, Industry 4.0 is leading the digital transformation in manufacturing sectors, wherein the industrial networks is evolving towards wireless connectivity and the automation process managements are shifting to clouds. However, such integration may introduce unwanted disturbances to critical industrial automation processes. This leads to challenges to guaran- tee the performance of critical applications under the integration of different systems.

In the work presented in this thesis, we mainly explore the feasibility of inte- grating wireless communication, industrial networks and cloud computing. We have mainly investigated the delay-inhibited challenges and the performance impacts of using cloud-native models for critical applications. We design a solution, targeting at diminishing the performance degradation caused by the integration of cloud computing.

PhD defence: Some Notes on Post-Quantum Cryptanalysis (Erik Mårtensson)

Publicerad: 2020-09-28

Thesis title: Some Notes on Post-Quantum Cryptanalysis

Author: Erik Mårtensson, Department of Electrical and Information Technology, Lund University

Opponent: Prof. Alexander May, Ruhr-Universität Bochum, Germany

When: 22 January 2021 at 9.15

Location: Online at the zoom platform - access by registration

The thesis for download (PDF, 4,7 MB)

Abstract

Cryptography as it is used today relies on a foundational level on the assumption that either the Integer Factoring Problem (IFP) or the Discrete  Logarithm Problem (DLP) is computationally intractable. In the 1990s Peter Shor developed a quantum algorithm that solves both problems in polynomial time. Since then alternative foundational mathematical problems to replace IFP and DLP have been suggested. This area of research is called post-quantum cryptology.

To remedy the threat of quantum computers the National Institute of Standards and Technology (NIST) has organized a competition to develop schemes for post-quantum encryption and digital signatures. For both categories latticebased cryptography candidates  dominate. The second most promising type of candidate for encryption is code-based cryptography.

The lattice-based candidates are based on the difficulty of either the Learning With Errors problem (LWE) or the Nth Degree Truncated Polynomial problem (NTRU), of which LWE is the focus of this thesis. The difficulty of both these
problems in turn relies on the difficulty of variations of the Shortest Vector Problem (SVP). Code-based cryptography is based on the difficulty of decoding random linear codes.

The main focus of this thesis is on solving the LWE problem using the Blum-Kalai-Wasserman algorithm (BKW).We have the following improvements of the algorithm.

1. We combined BKW with state-of-the-art lattice sieving methods to improve the complexity of the algorithm. We also elaborate on the similarities and differences between BKW and lattice sieving, two approaches that on a shallow level look very different.
2. We developed a new binary approach for the distinguishing phase of the BKW algorithm and showed that it performs favorably compared to previous distinguishers.
3. We investigated the Fast Fourier Transform (FFT) approach for the distinguishing part of BKW showing that it performs better than theory predicts and identically with the optimal distinguisher. We showed that we could improve its performance by limiting the number of hypotheses being tested.
4. We introduced practical improvements of the algorithm such as nonintegral step sizes, a file-based sample storage solution and an implementation of the algorithm.

We also improved the classical state-of-the-art approaches for k-sieving - lattice sieving where k vectors are combined at a time - by using quantum algorithms. At the cost of a small increase in time complexity we managed to drastically decrease the space requirement compared to the state-of-the-art quantum algorithm for solving the SVP.

Finally, we developed an algorithm for decoding linear codes where the noise is Gaussian instead of binary. We showed how code-based schemes with Gaussian noise are easily broken. We also found other applications for the algorithm in side-channel attacks and in coding theory.

Registration

Please register at https://www.lth.se/digitalth/events/register-2021-01-22-9-15 inorder to get an access link for the zoom platform.

PhD defence: High-Speed Analog-to-Digital Converters in CMOS

Publicerad: 2020-09-28

Author: Siyu Tan, Department of Electrical and Information Technology, LTH, Lund University

Faculty opponent: Prof. Piero Malcovati from the University of Pavia, Italy

Supervisor: Pietro Andreani, Department of Electrical and Information Technology, LTH, Lund University

Location: Online - link by registration

Registration

Please register at https://www.lth.se/digitalth/events/register-2020-12-18/ in order to get an access link to the online meeting.

The thesis for download [PDF] 

Abstract

The Analog to Digital (A/D) Converters (ADC) are vital components in high-performance radio devices. In the receiver end, the signal received by the analog front-end can not be directly analyzed by the digital core, thus requiring high-performance ADC circuits acting as bridges connecting the analog and digital domain. These circuits are integrated into Complementary Metal-Oxide-Semiconductor (CMOS) chips, which achieve high performance and consume low power at the same time.

In this research, various types of ADCs are analyzed both in architectural designs and component-level implementations. The goal is to find out optimized circuit designs to be used in high-speed communication devices in the future.

Two Successive-Approximation-Register (SAR) ADCs are studied. One of the SAR ADCs is a previously designed synchronous SAR ADC CMOS chip, implemented in the 22nm Fully Depleted Silicon On Insulator (FD-SOI) CMOS, whose measurement results are shown. An estimation and calibration technique for linearizing its Digital to Analog Converter (DAC) imbalance is presented.

Another SAR ADC is improved from the synchronous version, which has asynchronously clocked internal components, designed and implemented in 22nm FD-SOI. Two Continuous-Time (CT) ?? ADCs were designed and analyzed. One of the ?? ADCs is a high-speed converter implemented in 28nm FD-SOI CMOS, running at 5GHz sampling frequency and targeting at 250MHz signal bandwidth. Another ?? ADC is implemented in 65 nm CMOS and fabricated. It evaluates the effectiveness of digital calibration techniques in linearizing a critical outer-most DAC in the feedback.

All the ADC designs showing in this work are closely related to the state-of-the-art research works. The design specifications from the industry field are also carefully considered during the design phase. The introductions and the design details are explained in the first part of this dissertation, and the relevant research papers are attached in the second part.