L'accroissement d'efficacité des réseaux d'interconnexion et la vulgarisation des machines multiprocesseurs permettent la réalisation de machines parallèles à mémoire distribuée de faible coût: les grappes de multiprocesseurs. Elles nécessitent l'exploitation à la fois du parallélisme à grain fin, interne à un multiprocesseur offert par la multiprogrammation légère, et du parallélisme à gros grain entre les différents multiprocesseurs. L'exploitation simultanée de ces deux types de parallélisme exige une méthode de communication entre les processus légers qui ne partagent pas le même espace d'adressage. Le travail de cette thèse porte sur le problème de l'intégration de la multiprogrammation légère et des communications sur grappes de multiprocesseurssymétriques (SMP). Il porte plus précisément sur l'évaluation et le réglage dunoyau exécutif ATHAPASCAN-0 sur ce type d'architecture. ATHAPASCAN-0 est un noyau exécutif,portable, développé au sein du projet APACHE (CNRS-INPG-INRIA-UJF), qui combinela multiprogrammation légère et la communication par échange de messages. La portabilité est assurée par une organisation en couches basée sur les standards POSIX threads et MPI largement répandus. ATHAPASCAN-0 étend le modèle de réseaustatique de processus «lourds» communicants tel que MPI, PVM, etc, à celui d'un réseau dynamique de processus légers communicants. La technique de base est la multiprogrammation légère des communications et des calculs. La progression des communications exige la scrutation de l'état du réseau et l'enchaînement des opérations de transferts. L'efficacité repose sur la minimisation de ces opérations. De plus, l'emploi de multiprocesseurs ajoute des problèmes spécifiques dus à l'apparition d'un parallélisme réel entre calcul et communication. Ces problèmes sont présentés et des solutions sont proposées pour l'environnement ATHAPASCAN-0. Ces solutions sont évaluées sur des grappes de multiprocesseurs.

<p>Att ta ett större ansvar inom miljömässiga, ekonomiska och sociala frågor blir en allt viktigare punkt på många företags agendor, och en allt betydelsefullare aspekt för konsumenter att ta hänsyn till när de överväger köp av produkter eller tjänster. Företagsansvar, internationellt benämnt som corporate social responsibility eller CSR, har också fått ett genombrott bland myndigheter och andra officiella organ såsom FN och EU, som jobbar för att underlätta för företag genom olika riktlinjer och redovisnings­standarder för CSR. Fristående intresseorganisationer har också en viktig del i CSR-frågan, både som samarbetspartner och som granskare. Många av företagens intressenter är intresserade just av statistik och resultat, men hur kommunicerar ett konsumentföretag till sina kunder att de satsar på CSR-frågor? Hur kan företag använda av olika typer av strategier, kanaler och budskap för att stärka sitt varumärke och nå ut med sitt ansvarstagande? Trots att arbetet med CSR ofta föregås av noggranna strategiska överväganden och diskussioner om hur CSR påverkar varumärket, är det inte alla företag som har en tydlig plan för hur de ska kommunicera CSR mot konsumenter.</p><p>Denna uppsats syftar till att undersöka hur kommunikationen kring företags CSR-arbete sker, ser ut och uppfattas hos den intressentgrupp som företagets produkter eller tjänster riktar sig mot ­– konsu­menterna. I en form av nulägesanalys har fallstudier utförts på två svenska konsumentföretag, Arla och Löfbergs Lila, som båda har inledda CSR-åtaganden och har certifierade produkter i sitt sortiment. I fallstudierna ingick djupintervjuer med företagens CSR-ansvariga, kvalitativa innehålls­analyser av deras marknadsföringsmaterial och en enkätundersökning om konsumenternas kännedom och agerande inom området samt deras uppfattning av fallstudieföretagens ansvarstagande. Kopplat till en referens­ram innehållandes teorier om CSR som begrepp, CSR i dagens samhälle och hur CSR-orienterad kommunikation kan ske har frågor och modeller för dessa metoder tagits fram och analyserats.</p><p>Analysen visar på att inget av företagen ännu har en tydlig strategi för sin CSR-kommunikation. Företagen har implementerat CSR-arbetet väl internt inom företaget, men kommunicerar bara i liten utsträckning externt mot konsumenter. Det finns en svårighet i att involvera konsumenter i CSR-frågan och låta denna dialog influera och ingå i CSR-kommunika­tionen. Båda företagen ger tillgång till mycket information kring sitt ansvarstagande via sina webbsidor, men webbsidornas information tycks inte nå fram till konsumenterna då de inte är en välintegrerad del av marknadsföringen. Primärt knyts CSR-värden till företagens pro­dukter, och konsumenter relaterar företagens ansvarstagande med deras certifierade produkter framför­allt. Företagen använder sig av olika typer av kommunikations­budskap, vilka i Arlas fall är för vaga och visionsfokuserade, och i Löfbergs Lilas fall har svårt att väcka känslor för varumärket och ansvarstagandet. Konsumenterna visar på ett intresse för att agera i ansvars­frågor samt en viss kunskap inom området, men när det kommer till hur de uppfattar företagens ansvars­tagande finns det en stor osäkerhet och låg kännedom om vad företagen faktiskt gör inom CSR-området. En stor del av respondenterna har inte fått reda på någon information om hur företagen tar ansvar, och det är ännu inte många bland konsumenterna som aktivt söker upp information eller deltar i en dialog med företagen.</p> / <p>To take greater responsibility in environmental, economic and social issues is an increasingly important item on many companies' agendas, and an increasingly important aspect for consumers to take into account when considering purchase of a product or a service. This field, internationally called corporate social responsibility or CSR, has also made a breakthrough among authorities and other official orga­nizations such as the UN and the EU, which are facilitating for companies engaging in CSR by provi­ding various guidelines and accounting standards for CSR. Non-governmental organizations are also an important part of the CSR issue, both as partners and as reviewers. Many of the companies' stakehol­ders are interested in statistics and results, but how do consumer businesses communicate to their customers that they are investing in CSR issues? How can companies use different kinds of strategies, channels and messages to strengthen their brand and make the public notice their responsibility? Although the work with CSR is often preceded by careful strategic considerations and discussions about how CSR affects the brand, not all companies have a clear plan how to communicate CSR to consumers.</p><p>This thesis paper aims to examine how information concerning the companies' CSR initiatives is communicated, designed and perceived by the stakeholder group which the products or services are made for – the consumers. In the form of a situation analysis, case studies have been conducted on two Swedish consumer companies, Arla and Löfbergs Lila, both of which have initiated CSR commitments and have certified products in their range. The case studies included interviews with corporate CSR managers, qualitative content analysis of the companies' marketing materials and a survey of consumer knowledge and behavior in CSR issues as well as of the customers' view of the case study companies' responsibility. Linked to a theoretical framework including theories of CSR as a concept, CSR in today's society and how CSR-oriented communication can be designed, the issues and models for these methods have been developed and analyzed.</p><p>The analysis shows that neither of the companies have a clear strategy for their CSR communication. The companies have implemented CSR well within the organisation, but communicate only to a small extent externally. There is a difficulty in involving consumers in CSR issues and making this dialogue influence and be part of the CSR communication. Both companies provide access to much information about their responsibility through their web pages, but this information does not appear to reach consumers as the web pages are not well-integrated in the marketing. Primarily, the CSR values are connected to the companies' products, and consumers in particular relate the companies' CSR involvement to their certified products. The companies use different types of communication messages, which in Arla's case are too vague and vision focused, and in Löfbergs Lila's case have difficulties to arouse fee­lings for the brand and the CSR issues. Consumers show an interest to act on CSR issues and have a certain knowledge in the field, but when it comes to how they perceive the companies' CSR initiatives, there is a great uncertainty and low knowledge of what companies actually do in the CSR field. A large proportion of the respondents has not found out any information about how the companies are taking responsibility, and it is at this time not many among the consumers who actively seek out information or participate in a dialogue regarding CSR issues with companies.</p>

Dans les architectures parallèles à mémoire distribuée, la communication entre processus est un des facteurs de performance les plus importants pour les applications. Le système qui en a la charge, i.e, le noyau de communication, doit intégrer une fonctionnalité essentielle pour de telles architectures : le routage des messages. Cette fonctionnalité est assurée par une composante spécifique du noyau de communication: le noyau de routage, dont le rôle est l'acheminement d'un message d'un noeud émetteur vers un noeud récepteur. L'acheminement des messages nécessite une stratégie de routage qui spécifie les chemins de communication pour toute paire de processeurs (source, destination) du réseau d'interconnexion. Une telle stratégie de routage doit satisfaire d'une part, des critères de correction et d'autres part, des critères d'efficacité. Le but de cette thèse est la conception de stratégies de routage pour les réseaux de processeurs qui satisfont à la fois, les critères de correction et les critères d'efficacité. Nous proposons une méthode de conception de stratégies de routage, permettant par une démarche incrément-ale, de satisfaire les deux types de critère: la communication multi-niveaux et le schéma de communication primaire associé. Pour mesurer l'efficacité de la méthode, nous l'appliquons à un réseau particulier : la grille torique. Les différents algorithmes de routage obtenus sont corrects et très efficaces. Nous proposons également une technique d'implantation de notre méthode de routage, permettant le calcul des tables de routage directement sur le réseau de processeurs. Cette technique permet ainsi l'obtention d'un système autoconstructif.

Background:  Making customers loyal to the brand have become a key issue for marketers to achieve since it acts as a major contributor to competitive advantage. The brand image is argued to be the main source for brand loyalty and organizations continuously seeks for ways to achieve brand loyalty through enhancing their image. Employee branding makes it possible for organizations to consistently deliver a desired brand image to the customers, through its employees, and it could therefore be of importance to explore the relationship between employee branding and brand loyalty.  Research questions: RQ1: How does the organization’s management communicate its desired brand image to the employees? RQ2: How do the various sources of messages contribute to employees’ knowledge of the desired brand image? RQ3: How do the various sources of messages contribute to the upholding of the psychological contract between the employees and the organization? RQ4: How does the image projected by employees influence brand loyal customers? Purpose: The purpose of this thesis is to explore the relationship between an organization’s employee branding and brand loyalty. Methodology: Conducted as a single embedded case study, semi-structured interviews Conclusion: The empirical investigation revealed that employee branding activities could strengthen customers’ loyalty towards the brand. Employee branding therefore influence customers’ satisfaction, commitment, trust, and identification to the brand.

Dans ce mémoire nous abordons de prime abord la reconstruction d'arbres et de réseaux phylogénétiques, à travers deux méthodes d'inférence. Les arbres et les réseaux sont deux supports pour la représentation de l'évolution d'un groupe d'espèces étudiées. Les modèles d'évolution d'espèces qui seront traités sont les suivants : 1) Le modèle arborescent classique qui a longtemps été le seul support formel pour la représentation des relations génétiques entre les espèces. 2) Le modèle en réseau qui permet de représenter des mécanismes phylogénétiques importants pouvant jouer un rôle clé dans l'évolution et pouvant s'expliquer par le phénomène de l'évolution réticulée. Nous nous sommes particulièrement intéressés aux algorithmes d'inférence de réseaux de transferts horizontaux de gènes. Un transfert horizontal de gènes permet à deux espèces de s'échanger, partiellement ou totalement, différents gènes au cours de l'évolution. Le travail effectué sur la reconstruction d'arbres et de réseaux phylogénétiques a mené à la publication de trois articles. Ensuite, nous abordons le problème de réduction du temps d'exécution de différents programmes bioinformatiques. Ce problème a pris de l'ampleur à cause de la croissance du volume de données biologiques et du blocage de la puissance des ordinateurs autour de 3,4GHZ depuis environ deux ans. Nous décrivons un procédé d'accélération des calculs effectués par différents algorithmes d'inférence et de représentation de l'évolution des espèces, en utilisant le parallélisme. Le parallélisme mis en place a été réalisé à travers une librairie standard de passage de messages (Message Passing Interface). Nous montrons les différentes formes de parallélisme, les architectures de systèmes parallèles, quelques environnements qui permettent de supporter l'exécution des applications de façon à exprimer le parallélisme, ainsi que les approches utilisées pour paralléliser différents modèles d'évolution. Les versions parallèles des algorithmes d'évolution ont été développées et installées sur une « grappe » (i.e. cluster) Linux ayant 16 lames possédant chacune deux processeurs et sa propre mémoire. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : algorithmes d'évolution, arbre phylogénétique, réseau phylogénétique, transferts horizontaux de gènes, programmation parallèle, Message Passing Interface (MPI).

It is important to understand the development of depression, and how a family component to treatment affects early adolescent girls’ depression given the association between depression and negative future outcomes. A potential vulnerability to depression is the cognitive triad, which encompasses beliefs about the self, world, and future and is shaped by early learning experiences. Research indicates that the vulnerability originates from parent-child relationships and family messages, which are important in the development of youth cognitive styles. Previous research also indicates that family variables are important factors to consider in the treatment of depression. The purpose of the current study was to expand previous research by examining the roles of perceived family messages and the cognitive triad in the development of depression for early adolescent girls. The study also explored whether parent gender differentiated how family messages affect girls’ cognitions and depressive symptoms. The study evaluated how the addition of a parent training component to a school-based, group-administered CBT intervention affected change in the model’s variables in comparison to group-administered CBT intervention alone and a monitoring control condition. Participants included early adolescent girls diagnosed with depression and caregivers in the parental treatment component. Girls were randomly assigned to a CBT, CBT+PT, or minimal contact control condition. Ratings of girls’ perceptions of family messages, cognitions, and depressive symptoms were obtained at pre-treatment and post-treatment. Results from structural equation modeling indicated significant effects from perceived family messages to girls’ cognitions. Further, girls’ cognitions mediated the relation between perceived family messages and girls’ depressive symptoms at post-treatment for participants within the CBT and monitoring conditions. No significant differences were evident between parent gender and perceived messages. Results indicated that the addition of a parent component to the CBT intervention did not significantly differ from the CBT intervention alone in its effects on the variable relations within the model at post-treatment. Supplemental analyses highlighted parent attendance as a significant factor, with larger effects from the family messages on girls’ cognitions appearing when parents attended majority (six or more) of the eight parent training sessions. Implications, limitations, and areas for further research are discussed. / text

Pediatric overweight is defined as a body mass index (BMI) for age of 85th-95th percentile, and occurs in approximately 33.6% of adolescents 12-19 years of age. Hispanic adolescents are disproportionately at risk for overweight. Excess weight can predispose adolescents to develop diabetes mellitus type 2, coronary artery disease, hypertension, hypercholesterolemia, sleep apnea, osteoporosis, asthma, and certain types of cancer, whereas physical activity can help prevent and treat these diseases. Little is known about the factors that contribute to physical activity in Hispanic adolescent girls. The purpose of this study was to examine and compare the influence of personal characteristics, perceptual influences, interpersonal influences and sociocultural influences on physical activity in White and Hispanic adolescent girls. The theoretical framework for this study was self-designed--the Physical Activity Lifestyle Model. Data for this cross-sectional study was collected from girls age 11-14 who presented to the Children's Wellness Center in Del Valle, TX (N = 121) in the summers of 2011 and 2012. Most participants self-identified as Hispanic (n = 106). Participants completed a survey consisting of a 1-day physical activity recall, a demographic questionnaire, and several validated (primarily Likert-type) questionnaires. Height and weight were measured in the clinic. Data analysis began with descriptive analysis (mean, standard deviation and percentage) of demographic characteristics, dependent and independent variables, then Pearson correlations, and finally multiple linear regression to determine the influence of the independent variables on physical activity. No significant differences were found between ethnic groups on age, grade or school (p > .05). Physical activity was significantly related to body image (r = .189, p < .05), friend social support (r = .279, p < .01), and family social support (r = .401, p < .01). In addition, physical activity significantly predicted BMI percentile (B = -.043, SE = .019, t = -2.249, p = .027), appearance-related media messages (B = .259, SE = .127, t = 2.038, p = .044), pressures to be thin (B = .311, SE = .149, t = 2.082, p = .040), family social support for physical activity (B = .089, SE = .042, t = 2.139, p = .035), body image (B = .367, SE = .123, t = 2.987, p = .004), and physical activity enjoyment (B = .083, SE = .040, t = 2.089, p = .040). When designing an intervention to promote physical activity, health care providers and educators should consider that multiple external factors influence physical activity participation in Hispanic adolescent girls. Healthcare providers should involve parents and siblings in physical activity interventions for overweight adolescent girls. Interventions should be tailored to work with the adolescent girls' physical and social environment. Public health nurses should work with schools and communities to increase physical activity opportunities for adolescent girls in physical education classes, girls' sports, and after-school programs. / text

Το ηλεκτροεγκεφαλογράφημα αποτελεί μία μέθοδο καταγραφής των ηλεκτρικών σημάτων που παράγονται στο εσωτερικό του εγκεφάλου. Τα ηλεκτρικά αυτά σήματα διαχέονται από το σημείο που παράγονται προς την εξωτερική δερματική επιφάνεια του κρανίου όπου μετρώνται ως διαφορές δυναμικού. Αντικείμενο της διπλωματικής εργασίας είναι η σχεδίαση και η υλοποίηση μίας πειραματικής συνθήκης και της αντίστοιχης πειραματικής διάταξης, η οποία θα επιτρέπει την καταγραφή των Προκλητών δυναμικών του ατόμου που θα εκτελεί το πείραμα. Το κλινικό πρωτόκολλο που χρησιμοποιήθηκε εξετάζει δύο βασικά θέματα. Το πρώτο αφορά την αντίληψη του ανθρώπου για το χρόνο και το δεύτερο το πώς επηρεάζουν τα υποσυνείδητα μηνύματα τη λήψη αποφάσεων και την εγκεφαλική λειτουργία. Αρχικά, στο πρώτο κεφάλαιο της παρούσας διπλωματικής εργασίας, αναφέρονται οι βασικές αρχές του ηλεκτροεγκεφαλογραφήματος και το σύστημα διάδοσης της πληροφορίας στον ανθρώπινο εγκέφαλο. Επιπλέον περιγράφεται ο τρόπος με τον οποίο γίνεται η καταγραφή του σήματος του εγκεφαλογραφήματος και των Προκλητών Δυναμικών. Στη συνέχεια, στο δεύτερο κεφάλαιο παρουσιάζεται η θεωρία στην οποία βασίστηκε ο σχεδιασμός του κλινικού πρωτοκόλλου και η οποία αφορά δύο θέματα, την αντίληψη του ανθρώπου για το χρόνο και την επιρροή των υποσυνείδητων μηνυμάτων στη λήψη αποφάσεων. Στα επόμενα κεφάλαια περιγράφεται το κλινικό πρωτόκολλο που χρησιμοποιήθηκε και οι πειραματικές συνθήκες που εξετάστηκαν κατά τη διεξαγωγή των πειραμάτων. Ακόμα, γίνεται περιγραφή τόσο του υλικού όσο και του λογισμικού μέρους της πειραματικής διάταξης που αναπτύχθηκε για την υλοποίηση του κλινικού πρωτοκόλλου. Η πειραματική διάταξη που αναπτύχθηκε στα πλαίσια της διπλωματικής επιτρέπει τη σύνδεση με Ηλεκτροεγκεφαλογράφο με αποτέλεσμα τον συγχρονισμό της πειραματικής ακολουθίας και της καταγραφής του ηλεκτροεγκεφαλογραφήματος και των Προκλητών Δυναμικών. Με την πειραματική διάταξη που αναπτύχθηκε έγιναν δύο πειράματα. Η καταγραφή της εγκεφαλικής δραστηριότητας του κάθε εξεταζόμενου (ΗΕΓ) ήταν συνεχής για όλη τη διάρκεια της δοκιμασίας. Η εξαγωγή των Προκλητών Δυναμικών έγινε μετά το τέλος της καταγραφής με το πρόγραμμα EEGLAB, με το οποίο έγινε και η επεξεργασία τους. Τα Προκλητά Δυναμικά απεικονίστηκαν τόσο σε δισδιάστατα όσο και σε τρισδιάστατα μοντέλα κεφαλιών ενώ εξετάστηκε και το φασματικό περιεχόμενο του σήματος του ηλετροεγκεφαλογραφήματος για τις διάφορες πειραματικές συνθήκες. Από την ανάλυση των καταγραφών παρατηρήθηκαν κάποιες διαφορές μεταξύ των συνθηκών του πειράματος οι οποίες περιείχαν υποσυνείδητα μηνύματα και αυτών που δεν περιείχαν. Οι κορυφώσεις του δυναμικού εντοπίστηκαν τις ίδιες χρονικές στιγμές για όλες τις συνθήκες ενώ το πλάτος τους ήταν διαφορετικό μεταξύ των συνθηκών στις οποίες δινόταν στους εξεταζόμενους η σωστή απάντηση με υποσυνείδητο μήνυμα και σε αυτές που δεν δινόταν. / The electroencephalogram constitutes a method for recording electrical signals produced in the interior of the brain. These electric signals are diffused from the point of the brain where they are produced to the exterior dermal surface of the skull where they are measured as potential differences. The object of this diploma thesis is the design and the development of an experiment and the corresponding experimental setup, which allows the recording of the Event Related Potentials of the person who executes the experiment. The clinical protocol that is used examines two fundamental issues. The first is related to time perception while the second one examines if and how subliminal messages influence the decision making and the cerebral operation. Initially, in the first chapter of the present diploma thesis, the fundamentals of the Electroencephalogram and the system that is responsible for the distribution of the information inside the human brain is described. Following, Electroencephalogram and Event Related Potentials (ERPs) recordings are described. In the second chapter the theory on which the planning of the clinical protocol was based is presented. It concerns two research fields of psychophysiology; time perception and the influence of subliminal messages in decision-making. In the next chapters the clinical protocol and the experimental conditions that were examined during the experiments are described. Furthermore, there is a description of both the software and the hardware modules of the developed system. The experimental setup that was developed in the framework of the diploma thesis allows the connection to an Electroencephalograph and appropriate trigger signals are used in order to synchronize stimuli and recordings of EEG and ERPs. Two experiments were conducted. The recording of the brain activity was continuous for the whole duration of the experimental procedure. The Event Related Potentials were extracted post-hoc, after the end of the recording, using the EEGLAB software. The Event Relates Potentials were mapped both on two-dimensional and on three-dimensional head models. The spectrum of the electroencephalogram was also examined for the various experimental conditions. Analysis of the recordings revealed differences between the experimental conditions that contained subliminal messages in the EEG and ERPs. The ERPs’ peaks were detected at the same time delays for all the conditions. However, the amplitude of the peaks differed between the conditions where the right answers were given with subliminal messages and those that did not contain any subliminal messages.

SHAPING FUZZY GOALS THROUGH TEACHER-STUDENT INTERACTION: A DETAILED LOOK AT THE COMMUNICATION BETWEEN COMMUNITY COLLEGE FACULTY AND TRANSFER STUDENTS by Diana K. Leonard Faculty-student interactions have been largely neglected in the research regarding community colleges and community college transfer students. Yet faculty serve as points of institutional contact, and might also serve a central role in student experiences and decision-making. The purpose of this study was to increase our understanding of the dynamics and interactions that impact student experiences and decisions regarding transfer at the community college and to understand how those interactions contributed to goal formation. Symbolic interactionism (Blumer, 1969) provided a framework to guide the mixed-methods approach, which was primarily qualitative, utilizing online surveys and personal interviews to investigate students' interpretations of the student-teacher interactions. Quantitative data analysis measured teacher influence. 429 students who successfully transferred to a Research I university in the southwest, from in-state community colleges completed the survey. Ten students from this pool, subsequently interviewed, reflected various levels of uncertainty in their goals to transfer. These uncertain goals were termed "fuzzy" goals.In addition to symbolic interactionism as a framework, Stanton-Salazar's (1997) concept of institutional agents, supported with Bourdieu's (1977) cultural and social capital and Tinto's (1975) theory of social and academic integration were used to guide this study. Findings illustrated that students did utilize their teachers as institutional agents, who provided them with cultural knowledge and facilitated their understanding of procedures and processes through active as well as passive teacher-agency. Five themes emerged in students' interpretation of the student-teacher interactions: support, motivation, guidance, inspiration, and modeling. All had varying effects on students' uncertainty and contributed to shaping their fuzzy goals and to their social and academic integration into academe.This study can inform our understanding of the well-known gap in BA attainment between students who begin at a community college intending to transfer and students who begin at a four-year institution. Further, this study can inform strategic planning geared toward supporting teachers more fully in their role as institutional agents conveying social and cultural capital to students to increase their leverage for success once they transfer to the university.

The dissertation investigates communication quality issues in Vehicular Ad-hoc Network (VANET) using statistical analysis, experimental measurements, simulations and modelling. The Object of research is quality characteristics of Inter-Vehicle communication, which is based on IEEE 802.11p standard. The main objective of current research is to investigate Inter-Vehicle communication quality characteristics: packet loss and delay. Additionally propose a redundant safety message transmission method and create the confidence index concept and the calculation method. To reach these objectives following tasks have to be solved: define the boundary vehicular multi-hop transmission algorithms and investigate their performance for latency times defined in different use cases; analyze a packet loss caused by obstacles on the road and define approximation equations, for use in modelling tools; create the redundant packet transmission method for the lost safety message reduction; investigate the confidence index concept in a vehicular network and propose the confidence metrics calculation method; investigate the safe following distance dependency on road conditions and compare it to reliable communication distance. The dissertation consists of introduction, 4 chapters, conclusions and references. The introduction reveals the aim of the dissertation. The first chapter gives detailed overview of Inter-Vehicle communication environments and defines the main Inter-Vehicle communication... [to full text] / Disertacijoje nagrinėjama VANET ryšio kokybės problematika, analizei naudojant statistikos metodus, eksperimentinius tyrimus, modeliavimą ir simuliacijas. Tyrimų objektas yra ryšio tarp automobilių, kurio pagrindas IEEE 802.11p standartas, kokybės charakteristikos. Pagrindinis darbo tikslas – ištirti ryšio tarp automobilių kokybės charakteristikas: vėlinimus ir paketų praradimus. Papildomai pasiūlyti metodus ir algoritmus, mažinančius prarandamų saugos pranešimų skaičių. Pasiūlyti vairuotojo pasitikėjimo indekso koncepciją ir skaičiavimo metodus. Norint pasiekti šiuos tikslus, buvo spręsti sekantys uždaviniai: apibrėžti ribinius perdavimo grandine algoritmus ir ištirti jų efektyvumą perduodant pranešimus grandine; išanalizuoti duomenų paketų praradimus dėl kliūčių ir pateikti atitinkamus aproksimavimo algoritmus, tinkamus modeliavimams; sukurti dubliuotų saugos pranešimų perdavimo metodą, kuris leistų sumažinti prarandamų saugos pranešimų skaičių; sukurti vairuotojo pasitikėjimo indekso koncepciją ryšio tarp automobilių tinkle ir pasiūlyti pasitikėjimo indekso dedamųjų skaičiavimo metodus; ištirti saugaus važiavimo atstumo priklausomybę nuo kelio sąlygų ir palyginti ją su patikimo ryšio nuotolio išraiška. Disertaciją sudaro įvadas, 4 skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvade atskleidžiamas disertacijos tikslas. Pirmame skyriuje pateikiamas detalus ryšio tarp automobilių aplinkos savybių tyrimas. Yra... [toliau žr. visą tekstą]