Mathias Johanson | Chalmers University of Technology (original) (raw)

Papers by Mathias Johanson

Quality and User Experience, 2020

Virtual and augmented reality is increasingly prevalent in industrial applications, such as remot... more Virtual and augmented reality is increasingly prevalent in industrial applications, such as remote control of industrial machinery, due to recent advances in head-mounted display technologies and low-latency communications via 5G. However, the influence of augmentations and camera placement-based viewing positions on operator performance in telepresence systems remains unknown. In this paper, we investigate the joint effects of depth-aiding augmentations and viewing positions on the quality of experience for operators in augmented telepresence systems. A study was conducted with 27 non-expert participants using a real-time augmented telepresence system to perform a remote-controlled navigation and positioning task, with varied depth-aiding augmentations and viewing positions. The resulting quality of experience was analyzed via Likert opinion scales, task performance measurements, and simulator sickness evaluation. Results suggest that reducing the reliance on stereoscopic depth per...

Proceedings of the 4th EURASIP Conference on Video / Image Processing and Multimedia Communications, Mar 22, 2003

Ubiquitous use of real-time video communication on the Internet requires adaptive applications th... more Ubiquitous use of real-time video communication on the Internet requires adaptive applications that can provide different levels of quality depending on the amount of resources available. For video coding this means that the algorithms must be designed to be scalable in terms of bandwidth, processing requirements and quality of the reconstructed signal. This paper presents a novel video compression and coding algorithm targeted at delay-sensitive applications in heterogeneous network and computing environments. The algorithm, based on the embedded zerotree wavelet algorithm for still image compression, generates a highly scalable layered bitstream that can be decoded at different qualities in terms of spatial resolution, frame rate and compression distortion. Furthermore, the algorithm is designed to require only a minimal coding delay, making it suitable for highly interactive communication applications like videoconferencing. The performance of the proposed algorithm is evaluated by comparison with a non- scalable codec and the penalty in compression efficiency that the scalability requirement imposes is analyzed. The codec is shown to produce a scalable bitstream ranging from about 10 kbps to 10 Mbps, while the computational complexity is kept at a level that makes software implementation on CPU-constrained equipment feasible.

2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX), 2019

Journal of Marine Science and Engineering, 2021

Generating energy efficiency through behavioural change requires not only understanding and empat... more Generating energy efficiency through behavioural change requires not only understanding and empathy with user interests and needs but also the fostering of energy saving awareness, a technique and framework that supports operators and ship owners. There is strong potential to make use of different technical solutions to increase energy efficiency, but many cost-efficient solutions relate to carrot-and-stick incentives for operators to minimise energy consumption. These incentives range from voyage planning with weather routing eco-driving bonus, to torque limitations and changes in company policies, all of which demonstrate that the operators’ on-board importance for the energy consumption has been identified. Data collection will allow operators to make better decisions in the lifecycle of the ship from knowledge-driven design to operation, redesign and lifetime extension. Various systems are available for data acquisition, storage and analysis, some of which are delivered by well-...

2016 11th System of Systems Engineering Conference (SoSE), 2016

In this paper we present a System of systems approach for securing the availability of products o... more In this paper we present a System of systems approach for securing the availability of products or production systems in manufacturing or process industrial applications. The concept is based on condition monitoring and simulation-driven availability prediction, realised using a cloud computing infrastructure, where monitored data is processed and used for decision-making regarding support services and other interventions, to maximise the availability of the system. An industrial use case based on hydraulic drive systems powering a process industrial application is investigated from a System of systems perspective, and a prototype system architecture is described. Implications in terms of business models, including risk and profit sharing, are discussed and future opportunities of developing condition monitoring and availability prediction solutions based on System of systems principles are identified.

Volume 3: 26th Computers and Information in Engineering Conference, 2006

Signal Processing: Image Communication, 2020

The International journal of Multimedia & Its Applications, 2015

2011 13th International Conference on Transparent Optical Networks, 2011

Abstract—Next generation vehicles will provide powerful connectivity and telematics services, ena... more Abstract—Next generation vehicles will provide powerful connectivity and telematics services, enabling many new applications of vehicle communication. We will in this paper study the opportunities of performing remote vehicle diagnostics, where the diagnostic tool (test equipment) and the vehicle are separated by an internetwork, e.g. the Internet. The development of a prototype system for remote vehicle diagnostics, based on the emerging Diagnostics over IP (DoIP) ISO standard, is presented and early usage experiments with synchronous remote diagnostic read-out and control are described. A number of safety related issues are identified that will need closer study before a broad deployment of remote diagnostics services is feasible. Furthermore, a classification of vehicle diagnostics applications is provided, which is intended to elucidate the differences between synchronous (online) and asynchronous (offline) operation in local and distributed settings. Keywords-vehicle diagnostic...

Proceedings of the 12th Packet Video Workshop 2002, Pittsburg, PA, April 2002., 2002

This paper presents an approach to flow control for real-time, loss-sensitive, layered multicast ... more This paper presents an approach to flow control for real-time, loss-sensitive, layered multicast applications. The fundamentals of flow control for multicast applications are related and a novel delaybased flow control algorithm is introduced. The basic idea of the algorithm is to react to incipient congestion before packet loss occurs by monitoring variations in the one-way packet delay from sender to receivers. By using a hierarchical representation of the real-time data in combination with a layered multicast transmission model the flow control algorithm can be implemented entirely in the receivers. Furthermore, by constraining the bandwidth of the layers to a well-defined rate, the congestion control can be accomplished almost entirely without packet loss. This is particularly suitable for real-time multimedia conferencing applications that are inherently multipoint and loss-sensitive. The performance of the flow control algorithm in terms of link utilization, inter- and intra-p...

Networked and Electronic Media (NEM) Summit 2012, Istanbul, October 16-18, 2012, 2014

Abstract: A major shortcoming of traditional videoconferencing systems is that they present the u... more Abstract: A major shortcoming of traditional videoconferencing systems is that they present the user with a flat image of the other participants on a screen, while in real life, our binocular visual system gives us a three-dimensional view of the persons we are interacting with. Other common problems impairing the realism and usability of interpersonal video communication include lack of eye contact and a general feeling of a technology-induced barrier between the participants. In this paper, we present the development of a telepresence system based on novel concepts and new technology to give the users a sensation of being immersed in a shared space, while being geographically distributed. Key elements of the system are multiple cameras, autostereoscopic displays and a chroma keying based immersion technique combined with an eye contact mechanism. Our preliminary usage tests with the prototype system indicate that the novel mechanisms have a great potential of improving the feeling...

for real-time video transmission in heterogeneous network and computing environments, like the In... more for real-time video transmission in heterogeneous network and computing environments, like the Internet, need to be highly scalable and adaptive in terms of bandwidth and processing requirements. Layered video encodings in combination with layered transmission schemes have been proposed as a solution to network and terminal equipment heterogeneity. In this paper we identify the fundamental requirements of layered video encoding and transmission architectures, and review the different types of layering mechanisms available. Two applications are emphasized: multipoint videoconferencing and point-to-point video streaming. The implications of layer granularity for network bandwidth utilization are experimentally investigated through simulations.

Real-time video communication over packet networks is attracting increasingly more attention for ... more Real-time video communication over packet networks is attracting increasingly more attention for applications such as distributed collaborative work, teleteaching and telemedicine. Due to its sensitivity to delay, real-time communication is usually based on unreliable transport protocols, like UDP, since retransmission of lost packets is considered to take too long time. Instead of retransmissions forward error correction schemes have been proposed to make the applications more resilient to packet loss. Since the packet loss rate on the Internet typically fluctuates depending on the load of the network, the amount of redundancy applied by the error correction coding should ideally be adaptive to the amount of loss experienced on an end-to-end connection. In this paper an adaptive forward error correction scheme, based on Reed-Solomon erasure coding and receiver feedback, is presented. Moreover, an optimal packetization strategy for error protected video communication is suggested an...

With the growing popularity of audio and video communication services on the Internet, network op... more With the growing popularity of audio and video communication services on the Internet, network operators, service providers and application developers are becoming increasingly interested in assuring that their services give the best possible experience to the users. Since real-time audio and video services are very sensitive to packet loss, latency and bandwidth variations, the performance of the network must be monitored in real time so that the service can be adapted to varying network conditions by mechanisms such as rate control, forward error correction and jitter buffer adaptation. However, in order to optimize a service in terms of the user’s experience, the subjective effect that various network perturbations have on the user should be taken into consideration in the service adaptation mechanism. In this paper we present a novel approach to performance optimization based on rate adaptation driven by real-time estimation of the subjective Quality of Experience of a videoconf...

The trend in computer and network architecture is towards smaller and lighter devices that are mo... more The trend in computer and network architecture is towards smaller and lighter devices that are more or less constantly connected to the Internet through wireless network access technologies. For en ...

J. Inf. Technol. Constr., 2004

SUMMARY: Following the trend in computer and network architecture towards smaller and lighter dev... more SUMMARY: Following the trend in computer and network architecture towards smaller and lighter devices that are more or less constantly connected to the Internet through wireless access networks, mobile computing has emerged as a promising means to improve the possibilities of distributed collaborative teamwork. However, the mobility support implemented in state of the art collaboration software has hitherto been rather limited. In this paper we investigate the emerging technologies for wireless network access and mobile computing, how mobility support can be built into the software tools used today for distributed collaborative teamwork, and the benefits it gives users. The main focus is on synchronous, real-time communication tools like multimodal teleconferencing, and the perspective is both technical and methodological. Until now text has been the primary medium for mobile collaboration and our key finding is that user mobility support for video can substantially enhance the poss...

2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017

In this paper we describe a novel technological framework for capture and analysis of both object... more In this paper we describe a novel technological framework for capture and analysis of both objective measurement data and subjective user experience data for automotive applications. We also investigate how the framework can be extended to address privacy issues by enforcing a rigorous privacy model called differential privacy. The system under development integrates a telematics system with a smartphone app service architecture and a data-driven analytics framework. The hypothesis is that the framework will improve the opportunities of conducting large scale user trials of automotive functions and services, while improving the quality of collected data. To achieve this, a number of challenges are addressed in the paper, including how to design the subjective data capture mechanisms to be both simple to use yet powerful, how to correlate subjective data with objective measurement data, and how to protect the privacy of users.