Impact of Cache on Data-Sharing in Multi-Threaded Programmes

This thesis answers the question whether a scheduler needs to take into account where communicating threads in multi-threaded applications are executed. The impact of cache on data-sharing in multi-threaded environments is measured. This work investigates a common base-case scenario in the telecommunication industry, where a programme has one thread that writes data and one thread that reads data. A taxonomy of inter-thread communication is defined. Furthermore, a mathematical model that describes inter-thread communication is presented. Two cycle-level experiments were designed to measure latency of CPU registers, cache and main memory. These results were utilised to quantify the model. Three application-level experiments were used to verify the model by comparing predictions of the model and data received in the real-life setting. The model broadens the applicability of experimental results, and it describes three types of communication outlined in the taxonomy. Storing communicating data across all levels of cache does have an impact on the speed of data-intense multithreaded applications. Scheduling threads in a sender-receiver scenario to di↵erent dies in a multi-chip processor decreases speed of execution of such programmes by up to 37%. Pinning such threads to di↵erent cores in the same chip results in up to 5% decrease in speed of execution. The findings of this study show how threads need to be scheduled by a cache-aware scheduler. This project extends the author’s previous work, which investigated cache interference

Report on the In-vehicle Auditory Interactions Workshop: Taxonomy, Challenges, and Approaches

Jeon M, Hermann T, Bazilinskyy P, et al. Report on the In-vehicle Auditory Interactions Workshop: Taxonomy, Challenges, and Approaches. In: Proceedings of the 7th International Conference on Automotive User Interfaces and Interactive Vehicular Applications - Automotive'UI 15. 2015: 1-5.As driving is mainly a visual task, auditory displays play a critical role for in-vehicle interactions.To improve in-vehicle auditory interactions to the advanced level, auditory display researchers and automotive user interface researchers came together to discuss this timely topic at an in-vehicle auditory interactions workshop at the International Conference on Auditory Display (ICAD).The present paper reports discussion outcomes from the workshop for more discussions at the AutoUI conference

Impact of Cache on Data-Sharing in Multi-Threaded Programmes

This thesis answers the question whether a scheduler needs to take into account where communicating threads in multi-threaded applications are executed. The impact of cache on data-sharing in multi-threaded environments is measured. This work investigates a common base-case scenario in the telecommunication industry, where a programme has one thread that writes data and one thread that reads data. A taxonomy of inter-thread communication is defined. Furthermore, a mathematical model that describes inter-thread communication is presented. Two cycle-level experiments were designed to measure latency of CPU registers, cache and main memory. These results were utilised to quantify the model. Three application-level experiments were used to verify the model by comparing predictions of the model and data received in the real-life setting. The model broadens the applicability of experimental results, and it describes three types of communication outlined in the taxonomy. Storing communicating data across all levels of cache does have an impact on the speed of data-intense multithreaded applications. Scheduling threads in a sender-receiver scenario to di↵erent dies in a multi-chip processor decreases speed of execution of such programmes by up to 37%. Pinning such threads to di↵erent cores in the same chip results in up to 5% decrease in speed of execution. The findings of this study show how threads need to be scheduled by a cache-aware scheduler. This project extends the author’s previous work, which investigated cache interference

Impact of Cache on Data-Sharing in Multi-Threaded Programmes

This thesis answers the question whether a scheduler needs to take into account where communicating threads in multi-threaded applications are executed. The impact of cache on data-sharing in multi-threaded environments is measured. This work investigates a common base-case scenario in the telecommunication industry, where a programme has one thread that writes data and one thread that reads data. A taxonomy of inter-thread communication is defined. Furthermore, a mathematical model that describes inter-thread communication is presented. Two cycle-level experiments were designed to measure latency of CPU registers, cache and main memory. These results were utilised to quantify the model. Three application-level experiments were used to verify the model by comparing predictions of the model and data received in the real-life setting. The model broadens the applicability of experimental results, and it describes three types of communication outlined in the taxonomy. Storing communicating data across all levels of cache does have an impact on the speed of data-intense multithreaded applications. Scheduling threads in a sender-receiver scenario to di↵erent dies in a multi-chip processor decreases speed of execution of such programmes by up to 37%. Pinning such threads to di↵erent cores in the same chip results in up to 5% decrease in speed of execution. The findings of this study show how threads need to be scheduled by a cache-aware scheduler. This project extends the author’s previous work, which investigated cache interference

Customisable multitenant web form with JSF and MySQL

There is a tendency in Computer Science, nowadays, to move from single-user instances of application to web-based programs. With improvements in Information Technology and Computer Science fields of science it is possible nowadays to conduct business operations from within Internet. Thousands or in some cases millions of sheets of paper and man-hours of work can now be substituted by a single web form connected to a database on a certain website. In recent years a number of new technologies have been introduced to improve usability of Internet applications. It is now possible to create a multitenant piece of software that runs as one instance but serves different users. Nowadays, web forms, that are created for commercial purposes are normally not customisable and lack a possibility to adjust interface in order to suit needs of a particular client. Making multitenant web forms customisable is one of the most highly prioritised tasks for a number of companies that are working in the field of Internet. The aim of the study was to investigate means of creating a fully-functioning and customisable web form that is intended to be run on a server as a single instance. Through methods of user-specific configurations a test case was created that is able to serve a number of clients, giving each one a set of desired features. Before starting this work a following research question was raised: “How to develop the most optimised and the most versatile multitenant web form using JSF and MySQL?”. Also, working on this study makes an attempt to answer this question by doing a theoretical research first and then developing a working product that could be used on a market. A part of the study that focuses on development of the test case application is present in the study. Difficulties and issues that are faced while working multitenant cloud-enabled applications are outlined. Listings of programming code are given as examples where they are essential for understanding of the technical aspects of the research. Additionally, different stages of testing are described to outline strengths and weaknesses of the final product.The test case application may be found on GitHub.com website where it is stored as a public repository. A link to the project is https://github.com/Hollgam/multitenant_webforms

Impact of Cache on Data-Sharing in Multi-Threaded Programmes

This thesis answers the question whether a scheduler needs to take into account where communicating threads in multi-threaded applications are executed. The impact of cache on data-sharing in multi-threaded environments is measured. This work investigates a common base-case scenario in the telecommunication industry, where a programme has one thread that writes data and one thread that reads data. A taxonomy of inter-thread communication is defined. Furthermore, a mathematical model that describes inter-thread communication is presented. Two cycle-level experiments were designed to measure latency of CPU registers, cache and main memory. These results were utilised to quantify the model. Three application-level experiments were used to verify the model by comparing predictions of the model and data received in the real-life setting. The model broadens the applicability of experimental results, and it describes three types of communication outlined in the taxonomy. Storing communicating data across all levels of cache does have an impact on the speed of data-intense multithreaded applications. Scheduling threads in a sender-receiver scenario to di↵erent dies in a multi-chip processor decreases speed of execution of such programmes by up to 37%. Pinning such threads to di↵erent cores in the same chip results in up to 5% decrease in speed of execution. The findings of this study show how threads need to be scheduled by a cache-aware scheduler. This project extends the author’s previous work, which investigated cache interference

Supplementary data for the following paper: Crowdsourced measurement of reaction times to audiovisual stimuli with various degrees of asynchrony.

Supplementary data for the following paper: Bazilinskyy, P., & De Winter, J. C. F. (2018). Crowdsourced measurement of reaction times to audiovisual stimuli with various degrees of asynchrony. Human Factors, 60, 1192–1206

Blinded windows and empty driver seats: The effects of automated vehicle characteristics on cyclists’ decision‐making

Abstract Automated vehicles (AVs) may feature blinded (i.e. blacked‐out) windows and external human–machine interfaces (eHMIs), and the driver may be inattentive or absent, but how these features affect cyclists is unknown. In a crowdsourcing study, participants viewed images of approaching vehicles from a cyclist's perspective and decided whether to brake. The images depicted different combinations of traditional vehicles versus AVs, eHMI presence, vehicle approach direction, driver visibility/window‐blinding, visual complexity of the surroundings, and distance to the cyclist (urgency). The results showed that the eHMI and urgency level had a strong impact on crossing decisions, whereas visual complexity had no significant influence. Blinded windows caused participants to brake for the traditional vehicle. A second crowdsourcing experiment aimed to clarify the findings of Experiment 1 by also requiring participants to detect the vehicle features. It was found that the eHMI ‘GO’ and blinded windows yielded high detection rates and that driver eye contact caused participants to continue pedalling. To conclude, blinded windows increase the probability that cyclists brake, and driver eye contact stimulates cyclists to continue cycling. Our findings, which were obtained with large international samples, may help elucidate how AVs (in which the driver may not be visible) affect cyclists’ behaviour

Predicting perceived risk of traffic scenes using computer vision

Perceived risk, or subjective risk, is an important concept in the field of traffic psychology and automated driving. In this paper, we investigate whether perceived risk in images of traffic scenes can be predicted from computer vision features that may also be used by automated vehicles (AVs). We conducted an international crowdsourcing study with 1378 participants, who rated the perceived risk of 100 randomly selected dashcam images on German roads. The population-level perceived risk was found to be statistically reliable, with a split-half reliability of 0.98. We used linear regression analysis to predict (r = 0.62) perceived risk from two features obtained with the YOLOv4 computer vision algorithm: the number of people in the scene and the mean size of the bounding boxes surrounding other road users. When the ego-vehicle's speed was added as a predictor variable, the prediction strength increased to r = 0.75. Interestingly, the sign of the speed prediction was negative, indicating that a higher vehicle speed was associated with a lower perceived risk. This finding aligns with the principle of self-explaining roads. Our results suggest that computer-vision features and vehicle speed contribute to an accurate prediction of population subjective risk, outperforming the ratings provided by individual participants (mean r = 0.41). These findings may have implications for AV development and the modeling of psychological constructs in traffic psychology