2017-08-08 Kreativt kultursamtal för forskare och lärare
Datum: Måndag 8 Maj 2017
Plats: Skissernas Museum. Finngatan 2 i Lund.
Lunds universitets kultur- och museiverksamheter (LUKOM) inbjuder till ett kreativt samtal om hur kulturverksamheterna kan bidra till utbildning och forskning.
Välkomna att tillsammans med inbjudna talare och företrädare för LUKOM-verksamheterna diskutera hur museer och samlingar kan göras relevanta för utbildning och forskning.
Konferensen är gratis. Mer information kommer.
2017-02-14 Licentiate presentation by Dimitrios Vlastaras
Date: Feb 14, 2017
Opponent: Dr. Katsuyuki Haneda, Aalto University, Helsingfors, Finland.
Examinator: Doc. Anders J Johansson
Supervisor: Prof. Fredrik Tufvesson
Assistant supevisor: Prof. Ove Edfors
Title: Vehicular Communication in Obstructed and Non Line-of-Sight Scenarios
Since the invention of the first car available to masses, the 1908 Ford Model T, technology has advanced towards making car travel safer for occupants and bystanders. In recent years, wireless communication has been introduced in the vehicular industry as a means to avoid accidents and save lives.
Wireless communication may sometimes be challenging due to obstacles in the physical world that interact with wireless signals. Such obstacles may be dynamic, e.g. other vehicles in the traffic flow, or static, e.g. nearby buildings. Two scenarios are defined to describe those cases. The obstructed line-of-sight (OLOS) scenario is described as the case where a smaller obstacle, usually a vehicle, is placed in-between a transmitter and a receiver. This obstacle usually partially blocks communication and the receiver often moves in an out of the line-of-sight. The non line-of-sight (NLOS) scenario is described as the case where a larger obstacle completely blocks communication between a transmitter and a receiver. An example would be a building at an intersection which shadows the communication between two vehicles. In this thesis the OLOS and NLOS scenarios are investigated from different points of view.
In chapter 2, a road side unit (RSU) that has been constructed and evaluated for integrating older vehicles without wireless communication with newer vehicles using wireless communication is described. Older vehicles are being detected using a universal medium-range radar and their position and speed vectors are broadcasted wirelessly to newer vehicles. Tests have been performed by using the system in parallel with wireless enabled vehicles; by comparing the content in the messages obtained from both systems, the RSU has been found to perform adequately. Accuracy tests have been performed on the system and Kalman filtering has been applied to improve the accuracy even further.
Chapter 3 focuses on the OLOS scenario. A truck as an obstacle for wireless vehicular communication is being investigated. Real life measurements have been performed to characterize and model the wireless channel around the truck. The distance dependent path loss and additional shadowing loss due to the truck is analyzed through dynamic measurements. The large scale fading, delay and Doppler spreads are characterized as a measure of the channel dispersion in the time and frequency domains. It has been found that a truck as an obstacle reduces the received power by 12 and 13 dB on average in rural and highway scenarios, respectively. Also, the dispersion in time and frequency domains is highly increased when the line-of-sight is obstructed by the truck. A model for power contributions due to diffraction around the truck has also been proposed and evaluated using the previously mentioned real life measurements. It has been found that communication may actually be possible using solely diffraction around a truck as a propagation mechanism.
Finally, in chapter 4 a wireless channel emulator that has been constructed and evaluated is described. Modem manufacturers face a challenge when designing and implementing equipment for highly dynamic environments found in vehicular communication. For testing and evaluation real-life measurements with vehicles are required, which is often an expensive and slow process. The channel emulator proposed is designed and implemented using a software defined radio (SDR). The emulator together with the proposed test methodology enables quick on-bench evaluation of wireless modems. It may also be used to evaluate modem performance in different NLOS and OLOS scenarios.
2017-02-03 PhD Thesis defense by Gabriele Costanza
Date: Feb 3, 2017
Place: LTH, E-huset, Room 1406
2016-12-13 PhD Thesis defense by Qian Guo
Date: Dec 13, 2016
2016-11-24 Seminar by Fredrik Anderson, Centre for Mathematical Sciences, LTH
Date: Thursday, November 24
Title: Direction of arrival estimation for multiple frequencies
2016-11-15 PhD Thesis defense by Christopher Jämthagen
Date: Nov 15, 2016
This thesis presents new methods contributing to the area of software security. Both offensive and defensive methods are proposed, where the offensive methods presented in this thesis mostly deal with how an attacker can embed malicious code in a stealthy manner, and the defensive methods aims at detecting some form of attack.
The first approach deals with how a virtual machine can be detected and we discuss its use as both an offensive as well as a defensive method. We develop a proof-of-concept that aims to demonstrate how the technique works in practice.
Next we implement a GlobalPlatform compatible RPC mechanism utilizing both a hypervisor and SELinux and provide some benchmarks for both solutions.
Following this we will look at timestamping of data on a massive scale and how by utilizing the blockchain of the Bitcoin network, we can gain Byzantine fault tolerance for the Keyless Signing Infrastructure.
Then we will look at methods for obfuscating code by overlapping assembly instructions in machine code. We do this both by crafting custom no-operation instructions in the binary, but also provide a method to accomplish this in the source code when that source code will be compiled via a deterministic building process to produce the expected binaries.
Finally this thesis will conclude with a method for detecting Return Oriented Programming attacks by analyzing the raw data of a network stream.
2016-11-11 PhD Thesis defense by Aein Shiri Babadi
Date: Nov 11, 2016
Time: 10:15 am
This thesis investigates the electronic properties of a number of novel III-V materials and material combinations for transistor applications. In particular, high-κ/InAs metal-oxide-semiconductor (MOS) structures and transport properties of GaSb nanowires have been studied. III-V semiconductors are potential candidates to replace Si-based electronics due to their outstanding electron transport properties.
One of the main challenges in the performance of III-V MOS Field-Effect Transistors (MOSFETs) is the integration of high quality high-κ gate oxides. The quality of the oxide and the oxide-semiconductor interface affects the density of trapped charges which subsequently affects the device performance. The first part of the thesis is focused on studying the electrical properties of high-κ/InAs material system. A theoretical model of MOS capacitance-voltage (C-V) response is developed for narrow band gap semiconductors to quantify the densities of InAs-oxide interface and border traps. Different deposition conditions and surface passivation techniques are examined to minimize the trap densities. The optimized structure shows trap densities in the order of 1012 cm-2eV-1, which is comparable to the state-of-the-art high-κ on other high-electron-mobility III-Vs, such as InGaAs.
The second part of the thesis discusses the transport properties of GaSb nanowires. The electrical properties of the nanowires are characterized by fabricating lateral nanowire-based Field-Effect transistors. The thesis further explores a strategy for boosting the mobility in GaSb nanowires using strained GaSb/InGaAs core-shell nanowires.
2016-11-09 PhD Thesis defense by Tobias Tired
Date: Nov 9, 2016
This doctoral thesis is addresses two topics in integrated circuit design: multiband direct conversion cellular receivers for cellular frequencies and beam steering transmitters for millimeter wave communication for the cellular backhaul. The trend towards cellular terminals supporting ever more different frequency bands has resulted in complex radio frontends with a large number of RF inputs. Common receivers have, for performance reasons, in the past used differential RF inputs. However, as shown in the thesis, with novel design techniques it is possible to achieve adequate performance with a single ended frontend architecture, thereby reducing the complexity and pin-count. Millimeter wave integrated circuits development has previously not been subject to the mass production requirements that have been put on chip sets for cellular terminals, i.e. a minimum number of circuits, low supply voltage and power consumption, together with programmability to handle process spread and performance fine tuning. However, in the near future, when 5G networks will be deployed and the number of small pico- and femtocell base stations will explode, there will be a strong demand for low cost and high performance single-chip millimeter wave beam steering transceivers. The millimeter wave circuits presented in this work have been designed in a SiGe bipolar technology. Traditionally, SiGe designs use a higher supply voltage compared to CMOS. In this work, however, it has been shown that millimeter wave transceivers can be designed using a low supply voltage, thereby reducing the power consumption and eliminating the need for dedicated voltage regulators. Paper I presents a 28 GHz QVCO with an I/Q phase error tuning and detection. In paper II a 28 GHz beam steering PLL is presented together with measurement results for the design in paper I. Measurement results for the beam steering PLL are shown in paper III. Simulation results for a two-stage 81-86 GHz power amplifier are provided in paper IV. Paper V shows measurement results for two E-band power amplifiers. In paper VI, simulation results are presented for a complete E-band transmitter including a three-stage power amplifier. A reconfigurable single-ended CMOS LNA for different cellular frequency bands is presented in paper VII. A single-ended multiband RF-amplifier and mixer with DC-offset and second order distortion suppression in BiCMOS technology is presented in paper VIII.
2016-10-24 Master Thesis presentation by Antoniso Pateas' and Dragos Naegoes'
Date: Oct 24, 2016
Title: "Efficient IPv6 Network Discovery in Wireless Environment".
As the address space of IPv4 is being depleted with the development of IoT (Internet Of Things), there is an increasing need for permanent transition to the IPv6 protocol as soon as possible. Nowadays, many 3GPP Networks have implemented or will implement IPv6 in the near future for Internet access. These networks will also use NDP (Neighbor Discovery Protocol), which is the IPv6 tailored version of ARP (Address Resolution Protocol). The protocol is responsible of address auto-configuration, maintaining lists of all neighbors connected to a
network, verifying if they are still reachable, managing prefixes and duplicate address detection. The protocol is defined in RFC 4861 and although it works fine for wired connected devices, it has been proven highly inefficient in terms of battery lifetime saving, when wireless networks came to the market and its use increased tremendously. This thesis work is a continuation of a previous master thesis and complements the work done previously by showing how the solutions suggested in the new draft can be implemented at the router and host side and practically confirms the previous results of the theoretical analysis through simulation scenarios of sleep and wake-up of the nodes, performed in OMNeT++. Subsequently, the scalability of the system as a whole was analyzed with a simulation model containing a range of hosts from 1 to 100, and shows it can operate efficiently on a larger scale, reducing multicast messaging by almost 100%, presumably saving their battery power .
2016-10-20 Seminar by Karim Cherkaoui, visiting from Tyndall National Institute, Ireland.
Date: Thursday Oct 20
In this seminar the Nano-Electronic Materials and Devices group of the Tyndall National Institute in Cork, Ireland will be introduced. The group’s research areas and capabilities will be briefly presented. The high-k/III-V system has been the core of the research effort within the NMD group. The emphasis has been on the characterisation and metrology of interface states, oxide traps in the high-k/III-V metal oxide semiconductor using MOS capacitors and MOSFETs. Some examples of recent results obtained in this area will be presented and the relevance to the recently funded EU project (INSIGHT) will be discussed.