Incorporating Congestion Phenomena into Large Scale Strategic Transport Model Systems

Strategic traffic assignment (TA) models assess long-term effects of policies on route choices of travelers. To meet stability requirements, current strategic TA models lack modelling of queues. This thesis develops two TA models that include queue modelling whilst satisfying stability requirements along with a method to fuse observed link flows...

Contact duration: Intricacies of human mobility

Human mobility shapes our daily lives, our urban environment and even the trajectory of a global pandemic. While various aspects of human mobility and inter-personal contact duration have already been studied separately, little is known about how these two key aspects of our daily lives are fundamentally connected. Better understanding of such...

Intermittently-powered bluetooth that works

We present an architecture for intermittently-powered wireless communication systems that does not require any changes to the official protocol specification. Our core idea is to save the intermediate state of the wireless protocol to non-volatile memory within each connection interval. The protocol state is then deterministically restored at...

A Current Re-Use Quadrature RF Receiver Front-End for Low Power Applications: Blixator Circuit

This article presents the theory and implementation of a quadrature and differential RF front-end receiver. Combining balun, low-noise amplifier (LNA), mixer, and oscillator in a single stage, the proposed circuit, named the Blixator, is well suited for low-power applications. The baseband's transimpedance amplifier (TIA) also shares part of...

Deriving on-Trip route choices of truck drivers by utilizing Bluetooth data, loop detector data and variable message sign data

On important truck-dominated motorways, a large share of traffic consists of trucks. Our hypothesis is that these trucks do not always make optimal routing decisions which cause inefficiencies in the traffic system. Therefore, route choice of truck drivers is of interest to both transport planners and traffic management authorities. The...

A 0.5-V 1.6-mW 2.4-GHz Fractional-N All-Digital PLL for Bluetooth LE With PVT-Insensitive TDC Using Switched-Capacitor Doubler in 28-nm CMOS

This paper proposes an ultra-low-voltage (ULV) fractional-N all-digital PLL (ADPLL) powered from a single 0.5-V supply. While its digitally controlled oscillator (DCO) runs directly at 0.5 V, an internal switched-capacitor dc-dc converter ``doubles'' the supply voltage to all the digital circuitry and particularly regulates the time-to...

A Statistical analysis on the system performance of a bluetooth low energy indoor positioning system in a 3D environment

Since GPS tends to fail for indoor positioning purposes, alternative methods like indoor positioning systems (IPS) based on Bluetooth low energy (BLE) are developing rapidly. Generally, IPS are deployed in environments covered with obstacles such as furniture, walls, people and electronics influencing the signal propagation. The major factor...

A Bluetooth Low-Energy Transceiver with 3.7-mW All-Digital Transmitter, 2.75-mW High-IF Discrete-Time Receiver, and TX/RX Switchable On-Chip Matching Network

We present an ultra-low-power Bluetooth low-energy (BLE) transceiver (TRX) for the Internet of Things (IoT) optimized for digital 28-nm CMOS. A transmitter (TX) employs an all-digital phase-locked loop (ADPLL) with a switched current-source digitally controlled oscillator (DCO) featuring low frequency pushing, and class-E/F₂...

Power Efficient RF/mm-wave Oscillators and Power Amplifiers for Wireless Applications

A Fully Integrated Bluetooth Low-Energy Transmitter in 28 nm CMOS With 36% System Efficiency at 3 dBm

We propose a new transmitter architecture for ultra-low power radios in which the most energy-hungry RF circuits operate at a supply just above a threshold voltage of CMOS transistors. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply voltage and power without sacrificing its startup...

The Evaluation of Traffic Control in Changsha City

Different aspects of the traffic control system in the CBD of Changsha have been evaluated. A general issue is the safety conditions, which are evaluated qualitatively. The second issue is the low saturation flow observed on the intersections, that appear to be 20 to 30% lower than the ones in comparable situations in Europe or North America....

Monitoring travel times in an urban network using video, GPS and Bluetooth

The travel time is an important measure for the quality of traffic. This paper discusses a few methods to measure or estimate the travel time in urban road networks. First of all, it is important to know that urban travel times display a large variation, so that the measurement of a single (average) travel time is not so meaningful. The travel...