Unintentional injury is a leading cause of childhood death and disability in the U.S. Notably, atypically-developing children are at greater risk for unintentional injuries than their typically developing peers. A key question is how to prevent these injuries in both typically- and atypically-developing children. As children gain independence, responsibility for the regulation of risky behaviors must transfer from parents to children. This likely happens in a variety of ways, one of which is parent-child conversations about safety. Past work has examined the content of parent-child safety conversations in typically-developing children and found that mothers use disagreements, supported by references to dangerous features of the activity and the adverse outcomes that might result, as a means of bringing children around to their own way of thinking about safety. Still unknown is what these conversations look like while parents and children are engaged in common, yet potentially unsafe activities, such as crossing roads with traffic. Nor do we know what these conversations look like in at-risk populations, such as children with ADHD. Evidence points to poor executive function and oppositionality, commonly comorbid with ADHD, as driving the increased injury risk in this population. We assessed parent-child safety conversations in real time while parents and their children (with and without ADHD) were engaged in a simulated risky activity: crossing traffic-filled roads in our pedestrian simulator. Recorded conversations were coded and parents completed several questionnaires and diagnostic assessments regarding their and their child’s ADHD symptoms. While fewer symptomology differences related to parent-child conversations emerged than initially anticipated, many that did were primarily driven by oppositionality. These findings support previous claims that oppositionality increases injury risk in this population and contributes to poorer parent-child interactions.

Syftet med studien var att undersöka hur sköterskor som arbetar på en operationsavdelning där WHO´s Surgical Safety Checklist används, upplever kommunikation, samarbete och patientsäkerhet. Kort metodbeskrivning: Kvantitativ metod. Design: Deskriptiv, retrospektiv, icke-experimentell tvärsnittsstudie. Datainsamlingen genomfördes på en operationsavdelning som använt WHO´s Surgical Safety Checklist drygt ett år. Deltagarna fick anonymt besvara ett frågeformulär med strukturerade frågor, en översatt version av the Safety Attitudes Questionnaire (SAQ) anpassad till operationspersonal (OR). I studien undersöktes 3 av frågeformulärets 6 teman: säkerhetskultur, samarbetsklimat och stressidentifiering. Vidare undersöktes hur sköterskorna tyckte att kommunikationen på operationssalen fungerade; samt i vilken grad checklistan hade förbättrat kommunikationen, samarbetet och patientsäkerheten på operationssalen. Varje fråga besvarades genom en femgradig Likertskala. Huvudresultat: Fynden visar att man kan anta att sköterskorna upplevde att kvaliteten på kommunikationen och samarbetet på operationssalen var hög. Vidare ser det ut som om deltagarna ansåg att patientsäkerheten fungerade adekvat och att checklistan var viktig för patientsäkerheten. Resultaten visar också att sköterskorna tyckte att checklistan i hög grad har förbättrat kommunikationen, samarbetet och patientsäkerheten på operationssalen. Slutsats: Sköterskornas upplevelse av kommunikation, samarbete och patientsäkerhet på operationssalen antas huvudsakligen vara positiv 1 år efter att WHO´s Surgical Safety Checklist infördes. / The aim of the study was to examine the nurses´ experiences of communication, teamwork and patient safety in an operation ward where WHO´s Surgical Safety Checklist is used.  Quantitative method. Design: descriptive, retrospective, non-experimental cross-sectional study. The data collection was implemented in an operation theatre where WHO´s Surgical Safety Checklist had been applied for the last year. The participants responded to a structured questionnaire, a translated version of the Safety Attitudes Questionnaire (SAQ) adjusted for operating rooms (OR). In the study 3 of 6 themes of the questionnaire was examined: safety culture, teamwork climate and stress identity. The study examined the nurses´ experiences of communication in the operating room; and to what extent the checklist has improved the communication, teamwork and patient safety in the operating room. Each item was answered using a 5-point Likert scale. The findings reveal nurses´ experience of high quality of communication and collaboration in the operating room. Further it seems that the participants thought the patient safety was sufficient, and the checklist briefing was important for the patient safety. The results also show that nurses thought the checklist briefing has improved the communication, collaboration and patient safety in the operating room. The nurses´ experiences of communication, teamwork and patient safety in the operating room were assumed as mostly positive 1 year after the introduction of the WHO´s Surgical Safety Checklist.

Occupational health and safety (H&S) is important to the design, construction, maintenance, refurbishment and demolition of buildings and facilities in all branches of industry, business and commerce. H&S issues have been a major consideration in construction. Far too many people get hurt, injured or die even though the situation has improved over recent years. Accident and fatality rates continue to be significantly higher than other industry sectors. Although all parties involved in the construction industry may address their respective responsibilities, the lack of integration between each organization often results in communication problems which jeopardize H&S. Of particular note is the communication during the design phase. All information pertaining to the project must be readily accessible for all parties, to ensure smooth and hitch-free project execution. This research reviews the challenges in the communication of health and safety information in the design phase of construction projects. It characterizes the various aspects of collaborative communications at this stage and highlights the problem area. The research was conducted in the UK based on a combination of qualitative research methods including literature review, interviews and analysis of focus group interviews data. Observations on documentation and interviews are used to investigate the current industry practice. The literature reviews revealed that communication industry is facing challenges with its communication system due to the nature of industry itself. The construction industry is a fragmented and complex industry with too many parties involved in a project. These parties come from various backgrounds and involved in the project in a temporary duration. The parties who become team members must be able to establish a relationship in such a short period of time and create a communication system that enables all of the parties to collaborate and interact with each other.

<p>Inter-Vehicle Communication (IVC) is a vital part of Intelligent Transportation System (ITS), which has been extensively researched in recent years. Dedicated Short Range Communication (DSRC) is being seriously considered by automotive industry and government agencies as a promising wireless technology for enhancing transportation safety and efficiency of road utilization. In the DSRC based vehicular ad hoc networks (VANETs), the transportation safety is one of the most crucial features that needs to be addressed. Safety applications usually demand direct vehicle-to-vehicle ad hoc communication due to a highly dynamic network topology and strict delay requirements. Such direct safety communication will involve a broadcast service because safety information can be beneficial to all vehicles around a sender. Broadcasting safety messages is one of the fundamental services in DSRC. In order to provide satisfactory quality of services (QoS) for various safety applications, safety messages need to be delivered both timely and reliably. To support the stringent delay and reliability requirements of broadcasting safety messages, researchers have been seeking to test proposed DSRC protocols and suggesting improvements. A major hurdle in the development of VANET for safety-critical services is the lack of methods that enable one to determine the effectiveness of VANET design mechanism for predictable QoS and allow one to evaluate the tradeoff between network parameters. Computer simulations are extensively used for this purpose. A few analytic models and experiments have been developed to study the performance and reliability of IEEE 802.11p for safety-related applications. In this thesis, we propose to develop detailed analytic models to capture various safety message dissemination features such as channel contention, backoff behavior, concurrent transmissions, hidden terminal problems, channel fading with path loss, multi-channel operations, multi-hop dissemination in 1-Dimentional or 2-Dimentional traffic scenarios. MAC-level and application-level performance metrics are derived to evaluate the performance and reliability of message broadcasting, which provide insights on network parameter settings. Extensive simulations in either Matlab or NS2 are conducted to validate the accuracy of our proposed models.</p> / Dissertation

Eine gute Kommunikation und Zusammenarbeit zwischen den verschiedenen Mitgliedern von OP-Teams sind entscheidend für die Gewährleistung der Patientensicherheit. Die vorliegende Arbeit beschäftigt sich mit der Untersuchung der Qualität von Kommunikation und Teamarbeit in fünf verschiedenen Fachbereichen (Herzchirurgie, Anästhesie, OP-Pflege, Anästhesiepflege, Kardiotechnik). Dabei werden diese Daten erstmalig für deutsches Personal erhoben. Zudem wird zum ersten Mal ein nichtärztlicher, jedoch weisungsfreierer Fachbereich, die Kardiotechnik, in die Untersuchung einbezogen und diese Daten mit den Aussagen der Ärzte verglichen. Des Weiteren findet die Untersuchung der Effekte von drei Interventionen (Checkliste, OP-Statut, Team Time Out) auf die Qualität von Kommunikation und Teamarbeit statt. Die Datenerhebung erfolgte mit Hilfe eines standardisierten Fragebogens und mittels der Durchführung von Interviews. Die Vertreter der ärztlichen Berufsgruppen zeigen sich zufriedener mit der Kommunikation und Teamarbeit als die ihnen gegenüber weisungsgebundenen und hierarchisch untergeordneten Pflegekräfte. Wider Erwarten zeigen sich keine signifikanten Unterschiede in den Gesamtdurchschnittswerten der Kardiotechniker und denen der Ärzte. Dies wird auf die größere Entscheidungs- und Handlungsautonomie sowie auf die ausschließlich technische Arbeitsaufgabe der Kardiotechniker zurückgeführt. Zeitversetzt wurden zuerst eine interdisziplinäre Checkliste und zu einem späteren Zeitpunkt ein OP-Statut und das Team Time Out in den Arbeitsablauf des OP-Personals eingeführt, unter anderem mit dem Ziel, die Zufriedenheit mit der Teamkommunikation und -arbeit zu erhöhen, besonders bei den Pflegekräften. Die Beteiligung des Personals an den Fragebogenerhebungen war gering; zur Messung der Wirksamkeit der Checkliste konnte nur eine kleine Gesamtstichprobe analysiert werden, deren Daten keine Verbesserung der Qualität der Variablen aufzeigt. Für die Bewertung des Effekts des OP-Statuts und des Team Time Outs auf die Qualität der Kommunikation und der Teamarbeit konnten infolge der wenigen Probanden keine quantitativen Daten herangezogen werden. Die Interviewdaten machen deutlich, dass die Befragten infolge des OP-Statuts hauptsächlich eine Zunahme der Arbeitsdichte und der täglichen Arbeitsdauer wahrnehmen und Zweifel an der Umsetzbarkeit der Vorgaben haben. Weiterhin konnten durch die Interviews mögliche Gründe für die mangelnde Beteiligung an den Umfragen und für die Unzufriedenheit des Personals mit dem Statut ermittelt werden, welche sich vor allem auf organisationsinterne Aspekte wie die Bedeutung des Themas „Patientensicherheit“ in der Klinik beziehen. Bezüglich des Team Time Outs äußert sich die Mehrheit der Interviewpartner positiv und bestätigt das Potential dieser Intervention, die Teamkommunikation zu verbessern. Weiterer Forschungsbedarf wird aufgezeigt.:Inhalt Bibliographische Zusammenfassung I Abkürzungsverzeichnis II 1. Einleitung 1 1.1 Motivation 1 1.2 Ziele und Aufbau der Arbeit 3 2. Stand der Forschung 6 2. 1 Definitionen wichtiger Begriffe 6 2.2 Fehler in der Medizin 7 2.2.1 Auftretenshäufigkeit unerwünschter und vermeidbarer unerwünschter Ereignisse im Krankenhaus 7 2.2.2 Kosten unerwünschter und vermeidbarer unerwünschter Ereignisse 8 2.3 Fehlerforschung: Die Bedeutung der Human Factors 9 2.3.1 Ursprünge 9 2.3.2 Nicht-technische Fähigkeiten 10 2.3.3 Fehlerforschung, Patientensicherheitsbewegung, Human Factors und nicht-technische Fähigkeiten in der Medizin 11 2.3.4 Kommunikation und Teamarbeit 13 2.4 Kommunikation und Teamarbeit im Operationssaal 14 2.4.1 Das Setting “Operationssaal“ (OP) 14 2.4.2 Notwendigkeit von effektiver Kommunikation und Teamarbeit im Operationssaal 15 2.4.2.1 Verständnis von Teamarbeit 15 2.4.2.2 Hierarchieunterschiede 16 2.4.2.3 Gemeinsames mentales Modell 16 2.4.2.4 Interdependenzen 16 2.4.3 Diskrepante Bewertungen der Qualität von Kommunikation und Teamarbeit durch die verschiedenen klinischen Fachbereiche 17 2.4.4 Häufigkeit von mangelnder Kommunikation und Teamarbeit im Operationssaal 18 2.4.5 Konsequenzen ineffektiver Kommunikation und Teamarbeit 19 2.5 Maßnahmen zur Erhöhung der Patientensicherheit 19 2.5.1 Allgemein 19 2.5.2 Briefings/Team Time Out 20 2.5.3 Checklisten 21 2.5.4 Standardisierung von Prozessen – OP-Statute 22 2.6 Forschungshypothesen 23 3. Materialien und Methoden 25 3.1 Implementierte Interventionen zur Verbesserung der Qualität von Kommunikation und Teamarbeit 27 3.1.1 Interdisziplinäre Checkliste 27 3.1.2 OP-Statut 27 3.1.3 Team Time Out (Patientensicherheitsregelungen) 28 3.2 Untersuchungs- / Messinstrumente 28 3.2.1 Safety Attitude Questionnaire 29 3.2.2 Bewertung der Checkliste 30 3.2.3 Erfassung des Materialverbrauchs 30 3.2.4 Interviews 30 3.3 Durchführung der Studie 31 3.3.1 Erste Messung: Baselineerhebung Qualität Kommunikation und Teamarbeit/Prämessung zum Effekt der Checkliste 31 3.3.2 Implementierung der Checkliste 32 3.3.3 Zweite Messung: Postmessung zum Effekt der Checkliste 32 3.3.4 Dritte Messung: Follow Up-Messung zum Effekt der Checkliste/Prämessung zum Effekt des OP-Statuts und des Team Time Outs 33 3.3.5 Implementierung des OP-Statuts und des Team Time Outs 33 3.3.6 Interviewdurchführung 33 3.3.7 Vierte Messung: Postmessung zum Effekt des OP-Statuts und des Team Time Outs 34 3.4 Datenanalyse und statistische Auswertung 34 3.5 Rücklauf und Stichproben 36 4. Ergebnisse 40 4.1 Erste Messung: Baselineerhebung/Prämessung zum Effekt der Checkliste 40 4.2 Zweite Messung: Postmessung zum Effekt der Checkliste 46 4.3 Dritte Messung: Follow Up-Messung zum Effekt der Checkliste/Prämessung zum Effekt des OP-Statuts und des Team Time Outs 50 4.4 Interviews 51 4.5. Zielerreichung und Beantwortung der Hypothesen 71 5. Diskussion 74 5.1 Diskussion der Ergebnisse zu den Forschungsfragen und Hypothesen 74 5.2 Erfolge und Limitationen der Arbeit 88 5.3 Ausblick 91 5.4 Fazit 92 6. Zusammenfassung 94 7. Literatur- und Quellenverzeichnis 99 Anhang 116 Abbildungsverzeichnis 138 Tabellenverzeichnis 139 Lebenslauf 140 Erklärung über die eigenständige Abfassung der Arbeit 141 Publikationen 142 Danksagung 144

Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

This study explored the effect of public relations message strategies on beliefs, attitudes, and behavioral intentions of individuals regarding boater safety. An experiment was conducted using seven safety messages. Specifically, Fishbein and Ajzen’s (1975) theory of reasoned action and J.E. Grunig’s (1997) situational theory of publics were used to examine the communication effects of message strategies proposed by Hazleton and Long’s (1988) public relations process model. The findings of this study support the predictions of the theory of reasoned action—that salient beliefs predict attitude toward behavior and attitude toward behavior and subjective norm predict behavioral intent. Of the three attitude items measured— attitude toward message, attitude toward issue, and attitude toward organization—salient beliefs had the greatest effect on the attitude toward issue measure. Subjective norm was shown to be the stronger predictor of the three attitude items. In addition, support was found for the predictions of the situational theory of publics. The independent variables—problem recognition, constraint recognition, and level of involvement—were found to predict information seeking behaviors. However, the use of public relations message strategies in boater safety communication produced minimal effects on the same variables. It was determined that the power strategies, threat and punishment and promise and reward, would be most effective when communicating to a passive public such as the sample tested in this study. This study is significant to public relations literature because it examined how active boaters and non-boaters perceive safety messages. There appeared to be no research on the use of safe boating messages. Thus, there was no research on how public relations messages about boater safety affect boaters’ attitudes, awareness, and behavioral intentions prior to the implementation of this study. Determining effective boater safety messages will help to reduce boater accidents, injuries, and fatalities in years to come (U.S. Coast Guard, 2009), making this study both necessary and original.

Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

The need for interoperability in emergency communication systems has hastened the development of cognitive radio technology. However, even though a cognitive radio system technically interconnects participating agencies, interoperability depends not only on technical matters but also organizational issues related to the different individuals, working contexts and types of cooperative work involved. In order to support public safety workers such as police, firefighters, and Emergency Medical Service (EMS) providers appropriately, it is vital to consider the dynamics of the way they interact in any collaborative situation. The purpose of this study is to develop an in-depth understanding of interoperability and construct a new model based on this understanding, along with a working model of an interoperable communication system to serve as a design framework that (1) supports effective public safety communication and (2) incorporates cognitive radio capabilities to ensure optimal semantic interoperability. An adequate model for interoperability must include multiple dimensions to explain both the concept of interoperability in the public safety domain and its relationships with task characteristics and information needs. This model focuses primarily on the requirements for communication systems. The value perspective reflects the evaluation criteria for effective team communication such as semantic interoperability, task routineness, and information processing aspects. The design framework incorporates the proposed model into Work Domain Analysis (WDA). To achieve these research objectives, a series of studies was conducted. The first was a qualitative exploratory study that identified how the concept of interoperability is manifested in the public safety work domain. Through the use of semi-structured interviews, communication patterns in terms of interoperability were placed in a real world context. The responses from the participants were categorized in terms of the dimensions of interoperability and reinterpreted using sensemaking as a theoretical framework. The dimensions of interoperability identified consisted of information sharedness, communication readiness, operational awareness, adaptiveness, and coupledness. Based on these findings, a new instrument was proposed to measure interoperability for communication systems. This instrument was then statistically validated. The second study identified the effects of different types of operation and types of organization on interoperability, as well as investigating the relationships among interoperability, task routineness and information processing using Structural Equation Modeling (SEM). Based on this understanding and theoretical perspective, a new interoperable communication structure was delineated in the model. A prototype of a public safety cognitive radio communication system was then developed based on the proposed framework and examined using a focus group in order to validate the proposed model and design framework and highlight any usability issues that may affect the prototype's operational effectiveness. / Ph. D.