I många år nu har det varit vanligt förekommande att människor suttit hemma vid sin dator och med några få klick laddat ner filmer, musik och programvaror, till en början helt lagligt, men med åren har lagar kommit till som har gjort det mer och mer olagligt.Oavsett om det har varit lagligt eller inte, så är det troligt att många artister, filmmakare och liknande gått miste om stora summor pengar i förlorade inkomster på grund av att folk inte har betalat för att ta del av deras verk, utan istället valt att ladda ner dem över Internet.
Det faktum att fildelning har blivit så pass vanligt och att folk inte har sett det som ett särskilt allvarligt brott, har lett till att fildelning länge har varit ett hett omdiskuterat ämne i media, bland upphovsrättsinnehavare och bland folk i allmänhet. Upphovsmän och upphovsrättsinnehavare, såsom filmbolag, författare och artister har legat på och debatterat för att försöka få till en hårdare lagstiftning för att försvåra fildelning och kopiering av upphovsrättsskyddat material, samt för att få till hårdare straff mot fildelning.
Flera försök från beslutsfattare har gjorts för att råda bot på problemet, nya lagar har stiftats och avtal har skrivits under. Frågan är om de nya lagarna och avtalen gör någon nytta? Blir folk avskräckta från att fildela eller fortsätter de som förut? Många har säkert under många år blivit bortskämda med att kunna sitta hemma vid datorn och på några minuter få hem de senaste filmerna och den nyaste musiken helt gratis, vilket säkert gör det svårt att helt plötsligt sluta fildela och börja betala för film och musik igen.
Embedded systems are utilized in various modern-day applications in order to ease routine tasks that are otherwise demanding in manpower; an example of which is data sensing and acquisition. Modern sensor applications usually involve one or more embedded microcomputer systems with inputs from various sensors and a means of connection to transmit the acquitted data to its point of interest. While many sensor and acquisition applications and standards exist for industrial use, the consumer/small business markets for such devices seem to be fairly bleak in comparison. In this project, various data communication standards for transmitting information between sensors and acquisition devices are investigated. Wired, such as RS232, I²C, SPI and 1-Wire, as well as wireless protocols like Wi-Fi and ZigBee were studied. Then, a generic wireless data acquisition platform is designed and realized. The reference implementation connects to a wireless LAN network over Wi-Fi, starts a web server and serves HTML5 web pages and a CSS3 style sheet from SPI flash memory. The sensor data is collected from integrated sensor circuits over an I²C link. Device can run on 3 AA batteries for a combined uptime of at least 3 weeks. Lastly, possible expansion options for the implemented device are discussed and supplemented with real-world examples where possible. Feasible consumer applications for such a platform are then given to conclude.
Intelligent transportation is heavily reliant on radar, which have unique robustness under heavy rain/fog/snow and poor light conditions. With the rapid increase of the number of radars used on modern vehicles, most operating in the same frequency band, the risk of radar interference becomes an important issue. As in radio communication, interference can be mitigated through coordination. We present and evaluate two approaches for radar interference coordination, one for FMCW and one for OFDM, and highlight their challenges and opportunities. © 2021 IEEE.
Autonomous driving relies on a variety of sensors, especially radars, which have unique robustness under heavy rain/fog/snow and poor light conditions. With the rapid increase of the amount of radars used on modern vehicles, where most radars operate in the same frequency band, the risk of radar interference becomes a compelling issue. This article analyzes automotive radar interference and proposes several new approaches that combine industrial and academic expertise toward the goal of achieving interference-free autonomous driving (AD). © IEEE.
One of the biggest challenges in machine learning is data collection. Training data is an important part since it determines how the model will behave. In object classification, capturing a large number of images per object and in different conditions is not always possible and can be very time-consuming and tedious. Accordingly, this work explores the creation of artificial images using a game engine to cope with limited data in the training dataset. We combine real and synthetic data to train the object classification engine, a strategy that has shown to be beneficial to increase confidence in the decisions made by the classifier, which is often critical in industrial setups. To combine real and synthetic data, we first train the classifier on a massive amount of synthetic data, and then we fine-tune it on real images. Another important result is that the amount of real images needed for fine-tuning is not very high, reaching top accuracy with just 12 or 24 images per class. This substantially reduces the requirements of capturing a great amount of real data. © 2023 by SCITEPRESS-Science and Technology Publications, Lda.
In this survey, 105 papers related to interactive clustering were reviewed according to seven perspectives: (1) on what level is the interaction happening, (2) which interactive operations are involved, (3) how user feedback is incorporated, (4) how interactive clustering is evaluated, (5) which data and (6) which clustering methods have been used, and (7) what outlined challenges there are. This article serves as a comprehensive overview of the field and outlines the state of the art within the area as well as identifies challenges and future research needs. © 2020 Copyright held by the owner/author(s).
In this paper we present a self-learning method for low-level navigation for autonomous mobile robots, based on a neural network. Both corridor following and obstacle avoidance in indoor environments are successfully managed by the same network. Raw gray scale images of size 32 by 23 pixels are processed one by one by a feed forward neural network. The output signals of the network represent the appropriate steering actions of the robot.
In this paper a low-cost and low-weight attitude estimation system for an autonomous helicopter is presented. The system is based on an inclinometer and a rate gyro. The data coming from the sensors is fused through a complementary filter. In this way the slow dynamics of the inclinometer can be effectively compensated. Tests have shown that we obtained a very effective attitude estimation system.
In this paper we present a low-cost colour vision system mainly intended for robot design competitions, which nowadays is a popular, project-oriented, way of teaching mechatronics in engineering curriculums. The estimated cost is about 450 dollar inclusive colour camera and the system is small enough to be carried on-board relative small mobile robots. The system is build around a signal processor TMS C31. We also present and discuss the experiences made with the system in our robot design competition.
Vehicle-to-Everything (V2X) communication is essential for facilitating connected and automated driving, where vehicles and other road traffic participants share data instantaneously and cooperate to solve tricky traffic situations in milliseconds. This paper proposes two stochastic models for the V2X standard IEEE 802.11p to characterize amongst other things the Age of Information (AoI), a recently-proposed metric that measures the freshness of information. The first model is based on renewal process analysis of a tagged station with mean field approximation, while the second one adopts Markov chain approach with network level view. Analytical results show that IEEE 802.11p, given its adaptability to event-triggered and aperiodic messaging, supports advanced cooperative driving scenarios.
A fundamental paradigm of the Internet of Things (IoT) consists of agents that communicate updates to each other to perform joint actions, e.g., cooperative awareness in transportation systems, swarms of Unmanned Aerial Vehicles (UAVs), fleet of robots, automated assembly lines and logistics. A common feature of update messaging is emphasis on reliable throughput and freshness of collected data. We develop an analytical model that yields accurate predictions of all relevant metrics, both in terms of moments and probability distributions, for the case of one-hop broadcast update messages exchanged by using a CSMA-based wireless network. The model is validated against simulations and then applied to compare two update message scheduling approaches: providing a minimal buffer resource or providing no buffer. Surprisingly, we prove that having no buffer improves Age of Information (AoI) performance as well as message delivery rate, in spite of dropped packets. This is essentially due to much smaller congestion and hence collision probability in the wireless channel. From a system point of view this suggests a simple design of message handling, with no need of buffering and overwriting older messages. From a modeling point of view, the result supports the definition of simpler models that need not keep into account buffer state. © 2021 by IEEE.
The project aims to detect rear approaching vehicles for cycslist with a low power consumption. Study focuses on acoustic features of the sound of rear approaching vehicles and examines the useful indicators to detect the vehicles. The project includes more then one correlation and reveals their success rates for as many as samples possible.
Safety applications developed for vehicular environments require every vehicle to periodically broadcast its status information (beacon) to all other vehicles, thereby avoiding the risk of car accidents in the road. Due to the high requirements on timing and reliability posed by traffic safety applications, the current IEEE 802.11p standard, which uses a random access Medium Access Control (MAC) protocol, faces difficulties to support timely and reliable data dissemination in vehicular environments where no acknowledgement or RTS/CTS (Request-to-Send/Clear-to-Send) mechanisms are adopted. In this paper, we propose the Dynamic Token-Based MAC (DTB-MAC) protocol. It implements a token passing approach on top of a random access MAC protocol to prevent channel contention as much as possible, thereby improving the reliability of safety message transmissions. Our proposed protocol selects one of the neighbouring nodes as the next transmitter; this selection accounts for the need to avoid beacon lifetime expiration. Therefore, it automatically offers retransmission opportunities to allow vehicles to successfully transmit their beacons before the next beacon is generated whenever time and bandwidth are available. Based on simulation experiments, we show that the DTB-MAC protocol can achieve better performance than IEEE 802.11p in terms of channel utilization and beacon delivery ratio for urban scenarios.
Platooning is both a challenging and rewarding application. Challenging since strict timing and reliability requirements are imposed by the distributed control system required to operate the platoon. Rewarding since considerable fuel reductions are possible. As platooning takes place in a vehicular ad hoc network, the use of IEEE 802.11p is close to mandatory. However, the 802.11p medium access method suffers from packet collisions and random delays. Most ongoing research suggests using TDMA on top of 802.11p as a potential remedy. However, TDMA requires synchronization and is not very flexible if the beacon frequency needs to be updated, the number of platoon members changes, or if retransmissions for increased reliability are required. We therefore suggest a token-passing medium access method where the next token holder is selected based on beacon data age. This has the advantage of allowing beacons to be re-broadcasted in each beacon interval whenever time and bandwidth are available. We show that our token-based method is able to reduce the data age and considerably increase reliability compared to pure 802.11p. © 2015 IEEE.
Lately, all the top truck manufacturers are investing considerable resources in the research and development of platooning systems which would allow vehicles to save fuel and improve safety by travelling in a close-following manner. The platooning system requires frequent and reliable vehicle-to-vehicle communications. As platooning takes place in a vehicular ad hoc network, the use of IEEE 802.11p is close to mandatory. However, the 802.11p medium access method suffers from packet collisions and random delays. Most ongoing research suggests using TDMA on top of 802.11p as a potential remedy. However, TDMA requires synchronization and is not very flexible if the beacon frequency needs to be updated, the number of platoon members changes, or if re-transmissions for increased reliability are required. We therefore suggest a token-passing medium access method where the next token holder is selected based on beacon data age. This has the advantage of allowing beacons to be re-broadcasted in each beacon interval whenever time and bandwidth are available. We show that our token-based method is able to reduce the data age and considerably increase reliability considerably compared to pure 802.11p.
With the rapid growth in the automotive industry, vehicles have become more complex and sophisticated. Vehicle development today, involves integration of both electrical and mechanical systems. Their design and production are typically time and cost critical. To complement and support the process of vehicle development and design, majority of the automotive industry use modelling and simulationfor testing automotive applications, vehicle subsystems or the vehicle behaviour in its entirety.
For the purpose of traffic simulations, where a large number of vehicles and other elements of the road network are simulated, implementing a highly complex vehicle model would greatly affect the performance of the simulation. The complexity of the vehicle model would entail a higher computation time of the system, making it unsuitable for any real time application. There in lies the trade-off indesigning a model that is both fast and accurate. The majority of the vehicle models that have been designed are either domain specific, highly complex or generalized. Thus, in this thesis, two class specific vehicles’ kinematic models with good accuracy and low computation time are presented.
Two different modelling paradigms have been adopted to design and test these models. The results, challenges and limitations that pertain to these paradigms are also presented and discussed. The results show the feasibility of the proposed kinematic models.
Molecular communication is a relatively new communication paradigm for nanomachines where the communication is realized by utilizing existing biological components found in nature. In recent years researchers have proposed using bacteria to realize molecular communication because the bacteria have the ability to swim and migrate between locations, carry DNA contents (i.e. plasmids) that could be utilized for information storage, and interact and transfer plasmids to other bacteria (one of these processes is known as bacterial conjugation). However, current proposals for bacterial nanonetworks have not considered the internal structures of the nanomachines that can facilitate the use of bacteria as an information carrier. This article presents the types and functionalities of nanomachines that can be utilized in bacterial nanonetworks. A particular focus is placed on the bacterial conjugation and its support for multihop communication between nanomachines. Simulations of the communication process have also been evaluated, to analyze the quantity of bits received as well as the delay performances. Wet lab experiments have also been conducted to validate the bacterial conjugation process. The article also discusses potential applications of bacterial nanonetworks for cancer monitoring and therapy. © 2014 IEEE.
Det trådbundna telefonnätet har blivit för dyrt att underhålla och utveckla. Därför håller Telia nu på att ta ner delar av det. För de abonnenter som berörs av detta har Telia en lösning som de kallar fast mobil. Istället för att abonnenterna ringer via det trådbundna nätet ringer de via GSM-nätet istället.Målet med detta examensarbete är att skapa en alternativ lösning till Telias. Vi börjar med att undersöka hur det analoga nätet fungerar. Därefter bygger vi ett eget analogt gränssnitt som kommunicerar med vanliga hemtelefoner. En mikroprocessor kommer att styra en GSM-modul och tolka signaler från det analoga gränssnittet.Resultatet av detta arbete är en apparatur som vi kallar Teletrix – en fast mobil. Med en Teletrix kan vanliga hemtelefoner ringa via GSM-nätet med god samtalskvalitet och med grundläggande funktioner som kopplingston och ringsignal.
Detta projekt syftar till att möta behovet av en pålitlig backup-strömkälla förhushåll under strömavbrott genom att utforska potentialen i att använda enD24 dieselmotor. Det främsta målet med projektet är att möjliggöraautomatisk uppstart av motorn, vilket uppnås genom en sekvens avkomponenter som inkluderar en Arduino mikrokontroller. D24 motorn, medsin robusta design och långa livslängd, är en idealisk kandidat för dettaprojekt. I detta projekt ges en ekonomiskt och miljömässigt fördelaktiglösning för hushåll att få tillgång till backup-ström. Den framgångsrikaimplementationen av det automatiska uppstarts-systemet är det huvudsakligafokuset i projektet och säkerställer en pålitlig strömkälla för hushåll underströmavbrott.
I dagens samhälle är trenden att fler och fler människor införskaffar smartphones för att när som helst kunna vara uppkopplade mot internet. Detta gör att informationen en smartphone hanterar och sparar är viktigare och mer intressant för båda sidorna av lagen. Med denna ökning av smartphones har användandet av applikationer till sociala medier så som facebook ökat.I denna rapport utreds det vad en facebookapplikation lagrar för typ av information efter den har använts och hur pass noga det går att kartlägga vart applikationen har används. För att kunna göra detta krävs först en utredning på vilka sätt de går att hämta ut information ifrån en smartphone. I denna rapport har det alltså utretts huruvida de går att utvinna samma information med hjälp av flera metoder och om de går att uppnå samma resultat med hjälp av en utvinning med de olika metoderna. Vid analys av den utvunna datan visar det sig att applikationen lagrade den intressanta datan i databasfiler. Allt från meddelanden och statusuppdateringar till platsdata sparades i dessa databasfiler, vilket gjorde att enheten gick att kartlägga.
Applications involving multiple UAVs have gained increasing relevance in recent years, due to the benefits that cooperative systems tend to provide to their applications. In addition to performing several simultaneous tasks, the time spent to perform a certain task is reduced. In this article, an architecture for sharing navigation information is demonstrated to support applications composed of systems with multiple UAVs. © 2021. All Rights Reserved.
Detta projekt ämnar lösa problematiken med en användarvänlig träningsmaskin med målet attminska skador bland användarna. Detta ska ske genom att användarna själva inte ska behövaapplicera lösa vikter på en så kallad Smithmaskin. Projektets primära mål är att generera en kraftvia en teknisk lösning för att skapa motstånd på stången som kan användas under t.ex. bänkpress.Projektets syfte är att skapa en säker träningsmaskin ämnad för användare oavsett ålder, kön ellerfysiskt tillstånd. Ett annat mål med projektet är att skapa en prototyp på en redan befintligträningsmaskin men för en mindre kostnad. Metoden som tillämpas för projektet ärprocessbeskrivning, tester och undersökningar inom det kunskapsområde som berör studien.Projektgruppen har inhämtat kunskap och fakta via läroböcker samt vetenskapliga artiklar menockså via diskussioner med universitetsadjunkterna Hans-Erik Eldemark och Thomas Munther föratt sedan tillämpa denna information i arbetet. Projektet resulterade i en modifierad träningsmaskinämnad för att generera vikt via en växelströmsmotor där användaren kan välja vikt med ett intervallpå 5 kg via ett användarvänligt gränssnitt. Slutsatsen visar att projektet är genomförbart, att allahögprioriterade mål i kravspecifikationen uppfyllts samt att resultatet blev som förväntat.
In an application-layer distributed denial of service (App-DDoS) attack, zombie computers bring down the victim server with valid requests. Intrusion detection systems (IDS) cannot identify these requests since they have legal forms of standard TCP connections. Researchers have suggested several techniques for detecting App-DDoS traffic. There is, however, no clear distinction between legitimate and attack traffic. In this paper, we go a step further and propose a Machine Learning (ML) solution by combining the Radial Basis Function (RBF) neural network with the cuckoo search algorithm to detect App-DDoS traffic. We begin by collecting training data and cleaning them, then applying data normalizing and finding an optimal subset of features using the Genetic Algorithm (GA). Next, an RBF neural network is trained by the optimal subset of features and the optimizer algorithm of cuckoo search. Finally, we compare our proposed technique to the well-known k-nearest neighbor (k-NN), Bootstrap Aggregation (Bagging), Support Vector Machine (SVM), Multi-layer Perceptron) MLP, and (Recurrent Neural Network) RNN methods. Our technique outperforms previous standard and well-known ML techniques as it has the lowest error rate according to error metrics. Moreover, according to standard performance metrics, the results of the experiments demonstrate that our proposed technique detects App-DDoS traffic more accurately than previous techniques. © 2013 IEEE.
In this work we provide measurements on low power envelope detector and compare them with results predicted by theory. This envelope detector is supposed to be used as a part of low power Wake-up radio for RFID applications. In the work we were mostly interested in noise parameters and blocker effect verification.
The detector we use is based on CMOS transistors biased in subthreshold region. It gives us low power consumption and high sensitivity. For power consumption about 10 uA and signal to noise ratio equals to 10, the achieved sensitivity is 1.8 mV.
The results of the work can be used to build low power envelope detector for specific requirements.
Multi-user spatial multiplexing combined with packet aggregation can significantly increase the performance of Wireless Local Area Networks (WLANs). In this letter, we present and evaluate a simple technique to perform packet aggregation in IEEE 802.11ac MU-MIMO (Multi-user Multiple Input Multiple Output) WLANs. Results show that in non-saturation conditions both the number of active stations (STAs) and the queue size have a significant impact on the system performance. If the number of STAs is excessively high, the heterogeneity of destinations in the packets contained in the queue makes it difficult to take full advantage of packet aggregation. This effect can be alleviated by increasing the queue size, which increases the chances of scheduling a large number of packets at each transmission, hence improving the system throughput at the cost of a higher delay. © 1997-2012 IEEE.
Prospective IEEE 802.11p-based vehicular surveillance system, where video from the vehicle on-board camera is transmitted to the management center, is considered. Multi-hop transmission from the vehicle to the nearest roadside unit and then-via other roadside units-to the gateway is addressed. In this letter we assess the feasibility of such system by analyzing the video end-to-end distortion for a target vehicle, located several hops away from the gateway, when it is alone or there are also other vehicles transmitting video. We demonstrate the importance of dynamic adaptation of the video bit rate of each vehicle depending on the number and positions of the participating vehicles. © 2014 IEEE.
Wireless objects equipped with multiple antennas are able to simultaneously transmit multiple packets by exploiting the channel's spatial dimensions. In this paper, we study the benefits of such Multiple Packet Transmission (MPT) approach, when it is used in combination with a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol for fully interconnected networks, addressing the interactions between the two mechanisms and showing the performance gains that can be achieved. To this end, a very simple Media Access Control (MAC) protocol that captures the fundamental properties and tradeoffs of a CSMA/CA channel access protocol supporting MPT is introduced. Using this protocol as a reference, a new analytical model is presented for the case of non-saturated traffic sources with finite buffer space. Simulation results show that the analytical model is able to accurately characterize the steady-state behavior of the reference protocol for different number of antennas and different traffic loads, providing a useful tool for understanding the performance gains achieved by MAC protocols supporting MPT. © 2013 Elsevier B.V. All rights reserved.
The proceedings contain 18 papers. The topics discussed include: network coding as a WiMAX link reliability mechanism; initialization procedure of wireless network coding with hierarchical decode and forward strategy in random connectivity networks; a coded DHA FH OFDMA system with a noncoherent ML detector under multitone jamming; analysis of inter-RSU beaconing interference in VANETs; survey of energy efficient tracking and localization techniques in buildings using optical and wireless communication media; network coding as a WiMAX link reliability mechanism: an experimental demonstration; spectrum sensing with USRP-E110; power control for wireless networks with a limited number of channels; a measurement study for predicting throughput from LQI and RSSI; reality considerations when designing a TDMA-FDMA based link-layer for real-time WSN; and wireless groupcast routing with palette of transmission methods.
This book chapter introduces the use of Continuous Time Markov Networks (CTMN) to analytically capture the operation of Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) networks. It is of tutorial nature, and it aims to be an introduction on this topic, providing a clear and easy-to-follow description. To illustrate how CTMN can be used, we introduce a set of representative and cutting-edge scenarios, such as Vehicular Ad-hoc Networks (VANETs), Power Line Communication networks and multiple overlapping Wireless Local Area Networks (WLANs). For each scenario, we describe the specific CTMN, obtain its stationary distribution and compute the throughput achieved by each node in the network. Taking the per-node throughput as reference, we discuss how the complex interactions between nodes using CSMA/CA have an impact on system performance.
The main objective of this research is to study a novel method for safe maneuvering of articulated vehicles in warehouses. The presented method extends the concept of probabilistic planning on manifolds to articulated vehicles, which will be capable of driving, maneuvering and performing obstacle avoidance in any scenario. The proposed technique involves the extension of a parameterized space, developed for the reactive navigation of differential driven vehicles, to include an additional degree of freedom and use a probabilistic planner to calculate kinematically feasible trajectories. As a result, the algorithm is able to successfully generate maneuvers for an articulated truck and to navigate towards specific target points. The approach was validated using three problems representing different driving scenarios, demonstrating the possible utilization of the method in real-case scenarios. The solutions have been further benchmarked on multiple runs to evaluate success rate and to demonstrate the validity of the algorithm.
In recent years, messages and text posted on the Internet are used in criminal investigations. Unfortunately, the authorship of many of them remains unknown. In some channels, the problem of establishing authorship may be even harder, since the length of digital texts is limited to a certain number of characters. In this work, we aim at identifying authors of tweet messages, which are limited to 280 characters. We evaluate popular features employed traditionally in authorship attribution which capture properties of the writing style at different levels. We use for our experiments a self-captured database of 40 users, with 120 to 200 tweets per user. Results using this small set are promising, with the different features providing a classification accuracy between 92% and 98.5%. These results are competitive in comparison to existing studies which employ short texts such as tweets or SMS. ©2020 IEEE
Functional*Reactive Programming (FRP) is a declarative approach to modeling and building reactive systems. Priority-based FRP (P-FRP) is a formalism of FRP that guarantees real-time response. Unlike the classical preemptive model1 of real-time systems, preempted tasks in PFRP are aborted and have to restart when higher priority tasks have completed. Due to this abort-restart of nature of preemption, there is no single critical instant of release that leads to Worst-Case Response Time (WCRT) of lower priority P-FRP tasks. At this time, the only method for determining the WCRT is through an exhaustive enumeration of all release offsets of higher priority tasks between the release and deadline of the lower priority task. This makes the computational cost of WCRT dependent on the deadline of a task, and when such deadlines are large the computational costs of this technique make it infeasible even for small task sets. In this paper, we show that the release offsets of higher priority tasks have a lower and upper bound and present techniques to derive these bounds. By enumerating only those release offsets while lie within our derived bounds the number of release scenarios that have to be enumerated is significantly reduced. This leads to lower computational costs and makes determination of the WCRT in P-FRP a practically feasible proposition. © 2011 IEEE.
Kaiabachev, Taha, Zhu [1] have presented a declarative programming paradigm called Functional Reactive Programming, which is based on behaviors and events. An improved system called P-FRP uses fixed priority scheduling for tasks. The system allows for the currently executing lower priority tasks to be rolled back to restoring the original state and allowing a higher priority task to run. These aborted tasks will restart again when no tasks of higher priority are in the queue. Since P-FRP has many applications in the real time domain it is critical to understand the time bound in which the tasks which have been aborted are guaranteed to run, and if the task set is schedulable. In this paper we provide an analysis of the unique execution paradigm of the P-FRP system and study the timing bounds using different constraint variables.
1. R. Kaiabachev, W. Taha, A. Zhu, E-FRP with priorities, In the Proceedings of the 7th ACM & IEEE international conference on Embedded software, Pages: 221 - 230, 2007.
Overtaking on rural roads may cause severe accidents when oncoming traffic is detected by a driver too late, or its speed is underestimated. Recently proposed cooperative overtaking assistance systems are based on real-time video transmission, where a video stream captured with a camera installed at the windshield of a vehicle is compressed, broadcast through the wireless channel, and displayed to the drivers of vehicles driving behind. In such a system, it is of ultimate importance to deliver video information about the opposite lane with low end-to-end latency and good visual quality. In this paper, we propose reallocating the wireless channel resources in favor of the part of the captured video frame containing the image of the oncoming vehicle. To achieve this goal, we apply automotive radar for oncoming vehicle detection, and we use the image of this vehicle as a region-of-interest (ROI) for the video rate control. We present the theoretical framework, which describes the basics of such an approach and can serve as a useful guideline for the future practical implementation of the overtaking assistance systems. The benefits of our proposal are demonstrated in relation to the practical scenario of H.264/Advance Video Coding (AVC), IEEE 802.11p/Wireless Access for Vehicular Environments (WAVE) intervehicle communication standards, and currently used automotive radars.
Real-time video delivery in Vehicle-to-Infrastructure (V2I) scenario enables a variety of multimedia vehicular services. We conduct experiments with Dedicated Short Range Communications (DSRC) transceivers located in the mutual proximity and exchanging Skype video calls traffic. We demonstrate that the lack of coordination between the users both at the application as well as Medium Access Control (MAC) layers results in problems with quality of service provisioning even for the setup without vehicular mobility. © Copyright 2017 IEEE
This work is dedicated to a live video streaming in vehicular networks where the application-based inter-packet forward error correction is used for the packet loss protection. A practical way to apply such a protection at the video encoder side for the unknown channel loss rate is proposed. Experimental results which demonstrate the performance for the proposed approach for a scalable extension of the H.264/AVC standard (H.264/SVC) and for the non-standardized video codec based on three-dimensional discrete wavelet transform (3-D DWT) are provided.
In recently proposed cooperative overtaking assistance systems a video stream captured by a windshield-mounted camera in a vehicle is compressed and broadcast to the vehicle driving behind it, where it is displayed to the driver. It has been shown that this system can provide robust operation if video codec channel adaptation is undertaken by exploiting information from the cooperative awareness messages about any forthcoming increases in the multiple access channel load. In this letter we demonstrate the gains achievable in system performance when the video transmitter power control is also used. © 1997-2012 IEEE.
Prospective IEEE 802.11p-enabled automotive video applications are identified. Preliminary experimental results of inter-vehicular live video streaming for surveillance applications are presented. A test-bed for the demonstration of the achievable visual quality under different channel conditions is described.
IEEE 802.11p vehicle-to-vehicle and vehicle-to-infrastructure communication technology is currently an emerging research topic in both industry and academia. Respective spectrum allocation of 10 MHz channels in the 5.9 GHz band for USA and Europe allows considering inter-vehicle transmission of a live video information as a basis, which enables a new class of safety and infotainment automotive applications such as road video surveillance. This paper is first of its kind where such a video transmission system is developed and experimentally validated. We propose a low-complexity unequal packet loss protection and rate control algorithms for a scalable video coding based on the three-dimensional discrete wavelet transform. We show that in comparison with a scalable extension of the H.264/AVC standard the new codec is less sensitive to packet losses, has less computational complexity and provides comparable performance in case of unequal packet loss protection. It is specially designed to cope with severe channel fading typical for dynamic vehicular environments and has a low complexity, making it a feasible solution for real-time automotive surveillance applications. Extensive measurements obtained in realistic city traffic scenarios demonstrate that good visual quality and continuous playback is possible when the moving vehicle is in the radius of 600 meters from the roadside unit. ©2014 IEEE
Multi-stage programming is a method for improving the performance of programs through the introduction of controlled program specialization. This paper makes a case for multi-stage programming with open code and closed values. We argue that a simple language exploiting interactions between two logical modalities is well suited for multi-stage programming, and report the results from our study of categorical models for multi-stage languages.
A protocol and a communication mechanism intended for time and safety critical applications using a radio channel for information transport are considered jointly. The protocol is based on a scheme of retransmissions done on demand within a given time window. Each retransmission is coded with a varying number of redundant symbols. The set of blocks used for retransmission is controlled by two quality-of-service parameters: deadline for the transmission and the probability that the correct decoded message will reach the recipient before this deadline. Analysis of a protocol model indicates that it is possible to transmit time critical information in a mobile wireless system with very low error probabilities in an industrial environment.
An interaction protocol for cooperative platoon merge on highways is proposed. The interaction protocol facilitates a challenge scenario for the Grand Cooperative Driving Challenge (GCDC) 2016, where two platoons running on separate lanes merge into one platoon due to a roadwork in one of the lanes. Detailed interaction procedures, described with state machines of each vehicle are presented. A communication message set is designed to support platoon controllers to perform safe and efficient manoeuvres. © 2015 IEEE.
A need to apply the massively parallel computing paradigm in embedded real-time systems is foreseen. Such applications put new demands on massively parallel systems, different from those of general purpose computing. For example, time determinism is more important than maximal throughput, physical distribution is often required, size, power, and I/O are important, and interactive development tools are needed. The paper describes an architecture for high-performance, embedded, massively parallel processing, featuring a large number of nodes physically distributed over a large area. A typical node has thousands of processing elements (PEs) organized in SIMD mode and is the size of the palm of a hand, Intermodule communication over a scalable optical network is described. A combination of wavelength division multiplexing (WDM) and time division multiplexing (TDM) is used. © 1994 IEEE.
E-commerce is a growing market for selling gods and digital images are often used to display the product. However, there is a problem when the color of the object does not match the reality. This can lead to a dissatisfaction of the customer and a return of the product. Returned goods causes a significant loss in revenue for the suppliers. One reason for untruthful rendering of colors in images is due to different temperatures, or colors, of the illumination sources lighting the scene and the object. This effect can be reduced by a method called white balance. In this thesis, an algorithm based on the technique in Hsu et al. was implemented for a more truthful rendering of images of clothes and toys used in e-commerce. The algorithm removes unwanted color casts induced in the image from two different illumination sources. The thesis also marks important details missing in aforementioned paper as well as some drawbacks of the proposed technique, such as high processing time.
The most fundamental task for any mobile robot is to perform self-localization in the world in which it is currently active, i.e. determine its position relative its world. Encoders that count wheel rotations are often used, which can be turned into relative position estimates by mean of integration. This process is commonly referred to as dead reckoning. Unfortunately, the errors in such position estimates grow over time due to the underlying measurements errors, which means that the errors in the dead reckoning estimates must be regularly corrected by absolute postion estimates provided by other sensors. The goal of this thesis is to evaluate the possibilities of using so called scan mathing algorithms for robust position estimation of a mobile robot, especially in environments that change over time. A scan is a set o range measurements of the environment provided by e.g. a laser scanner. By comparing a scan taken at the actual poition of the robot with a scan previously taken and stored in a map of the environment, an estimate of the absolute position of the robot can be obtained. It is important that scan matching algorithms are robust against changes in the environments, are robust against different types of environments and can judge their own results.
The main contributions of the thesis are threefold. First, two new sector-based scan matching algorithms are presented that are based on two existing scan-matching algorithms known as the Cox's and IDC algorithm. The sector-based variants, Cox-S and IDC-S, increase the performance of the existing algorithms, especially in environments containing severe changes. Second, two new methods are presented for estimating the uncertainty of the IDC algorithm. These methods improve the self-judgment of the IDC and IDC-S significantly, as the existing method for estimating the uncertainty was not reliable. Third, the new sector-based scan matching algorithms are evaluated and compared to the existing algorithms on the basis of simulations and real world experiments made with two different mobile robots. The experiments focus on the performance of the algorithms in hanging environments, and on their performance as part of a complete loalization system, i.e. fusing the outcome with dead reckoning. The experiments show a clear advantage of using sector-based scan matching algorithms in terms of increased robustness against changed environments. The experiments show that use especially of a combination of the two sector based algorithms Cox-S and IDC-S, while also using the new method for estimating the uncertainty of the IDC-S, achieves significantly better performance in changing environments compared to the existing algorithms.
Previously we have presented a new scan-matching algorithm, based on the IDC - Iterative Dual Correspondence- algorithm, which showed a good localization performance even in the case of severe changes in the environment. The Problem of the IDC-algorithm is that there is no good way to estimate the covariance matrix of the position estimate, which prohibits an effective fusion with other position estimates from other sensors, e.g by means of the Kalman filter. In this paper we present a new way to estimate the covariance matrix, by estimating the Hessian matrix of the error function that is minimized by the IDC scan-matching algorithm. Simulation results show that the estimated covariance matrix correspond well to the real one.