Studiens syfte var att undersöka upplevelser av arbetstillfredsställelse hos brandmän. Forskningen om brandmän har i ringa omfattning fokuserat på hälsofrämjande faktorer inom yrket och det finns begränsat med kvalitativ forskning kring arbetstillfredsställelse hos brandmän. För denna studie användes därför en kvalitativ metod. Data har samlats in genom semistrukturerade intervjuer av tio brandmän verksamma inom heltidsstyrkan på en brandstation i Norge. Intervjuerna analyserades enligt en fenomenografisk ansats, för att kvalitativt undersöka olika upplevelser av fenomenet arbetstillfredsställelse. Studien visade att olika faktorer inom den psykosociala och organisatoriska arbetsmiljön har betydelse för arbetstillfredsställelse hos brandmän. De intervjuade brandmännen upplevde arbetet som meningsfullt och uttryckte att de ser fram emot att gå till jobbet. Lärande och säkerhet i arbetet relaterades till arbetstillfredsställelse, liksom tydliga krav och gemensamma strukturer i arbetet. Gemenskapen på arbetsplatsen kopplades till arbetstillfredsställelse, speciellt lyftes stödet från kollegor fram som viktigt. Brandmännen upplevde arbetstillfredsställelse genom styrning och stöd från ledare, men olika ledaregenskaper beskrevs som viktiga och det betonades att ledarskapet måste anpassas till situationen. Arbetstillfredsställelse vid operativt arbete relaterades till att vara förberedd inför händelser, att samarbetet vid insatser fungerar och att det ständigt dyker upp nya utmaningar som måste hanteras. Resultaten från denna studie kan understödja det hälsofrämjande arbetet på brandstationen där studien har genomförts och inom andra jämförbara verksamheter. / The purpose of this study was to examine experiences of job satisfaction among firefighters. The previous research on health-promoting factors within the fire service is scarce and there is limited qualitative research on job satisfaction among firefighters. A qualitative method was subsequently used for this study. Data were collected through semi-structured interviews with ten full-time firefighters at a fire station in Norway. The interviews were analyzed using a phenomenographic approach, to qualitatively examine different experiences of the phenomenon of job satisfaction. The study showed that various factors within the psychosocial and organizational work environment are of relevance to job satisfaction among firefighters. The interviewed firefighters experienced their work as meaningful and looked forward to going to work. Learning and safety at work, as well as clearly defined requirements and shared structures within the organization were related to their job satisfaction. The firefighters experienced job satisfaction through support from colleagues and leaders. Job satisfaction in operational work was related to preparedness, cooperation and coping with new challenges. The results from this study may support the health-promotion efforts at the fire station where the study was carried out, as well as in other comparable organizations.

My thesis paper is focused on preparation of early school age children in fire sport. This sport is known as adult sport and only marginally. In theoretical part I want to bring near ideas of this sport. I deal with history of fire departments and children in these departments, next I am focused on fire game "Plamen"(Flame) and also trainer personality. Research is focused on searching and evaluation of informations about preparation early school age children in fire sport in Benešov district.

BACKGROUND and OBJECTIVES: Low-back overexertion injuries represent a large proportion of fireground “strains, sprains and muscular pains” and are a leading cause of disability and early retirement in firefighters. Given the inherently hazardous and unpredictable nature of many fireground activities, it is often infeasible to implement “task-focused” ergonomic controls and there are limited options to accommodate injured firefighters. Accordingly, effective and practical “worker-focused” injury prevention approaches are needed. Toward this end, four studies were conducted to address the following global thesis objectives: 1) Examine the possible role that firefighters’ personal movement strategies could have on their occupational low-back loading demands and injury potential; and 2) Compare the effects of two different exercise approaches on firefighters’ occupational low-back loading demands and injury potential. STUDY 1: Low-Back Loading Demands during Simulated Firefighting Tasks – Inter-Subject Variation and the Impact of Fatigue and Gender. Background: Non-modifiable fireground duties are considered hazardous for low-back health, but personal movement strategies could modulate low-back loading demands and injury potential. Study objectives were to quantify low-back loading demands during simulated firefighting tasks and to examine the impact of fatigue and gender on the peak loading response. Methods: Ten men and 10 women performed a battery of laboratory-simulated firefighting tasks before and following repeated bouts of a fatiguing stair-climbing protocol. An EMG-assisted three-dimensional dynamic biomechanical model was used to compute peak L4/L5 joint forces during task performance. Results: Peak low-back loading demands varied considerably between subjects and tasks, but 70% of all loading variables examined were of greater magnitudes in male subjects and 40% of all loading variables were of lower magnitudes in both males and females after stair-climbing. Some inter-subject variation in low-back loading was attributed to body size differences, but between- and within-subject differences in movement strategies also contributed to low-back loading variability between subjects and over time. Conclusions: Results of this study suggest that characteristics of individuals, tasks performed, and physical fatigue may influence peak low-back loading demands and injury potential in firefighters. Despite considerable inter-subject variation in the internal low-back loading response to fixed external task and environmental constraints, opportunities to attenuate low-back loading demands through movement behaviour adaptations alone may be limited to only a subset of fireground activities. STUDY 2: Ankle Immobilization alters Lifting Kinematics and Kinetics – Occupational Low-Back Loading Demands and Potential for Injury. Background: Firefighters with lingering lower extremity functional impairments could be forced to move in ways that increase their potential for sustaining occupational low-back lifting injuries. The study objective was to examine the impact of unilateral ankle immobilization on lifting kinematics and kinetics. Methods: With and without their right ankle immobilized, 10 male volunteers performed laboratory-simulated occupational lifting tasks. Together with force platform data, three-dimensional kinematics of the lumbar spine, pelvis, and lower extremities were collected, and a three-dimensional dynamic biomechanical model was used to calculate peak low-back compression and shear loading demands. Results: In comparison to the unaffected conditions, ankle immobilization resulted in less knee (p-values between 0.0004 and 0.0697) and greater lumbar spine (p-values between 0.0006 and 0.3491) sagittal motion when lifting. Associated with this compensatory movement strategy were greater L4/L5 anterior/posterior reaction shear forces (p-values between 0.0009 and 0.2450). However, in a few cases where individual compensatory movement strategies differed from the “group” response (i.e., subjects increased their sagittal knee and hip motion on the affected side), peak L4/L5 joint compressive loads increased while the peak L4/L5 anterior-posterior shear did not change. Conclusions: Distal lower extremity joint dysfunction can alter the way in which individuals move and load their low-backs when lifting. The specific ways in which individuals compensate for personal movement constraints could alter the potential site and mechanism of occupational low-back injury. STUDY 3: FMS™ Scores and Occupational Low-Back Loading Demands – Whole-Body Movement Screening as an Ergonomic Tool? Background: Results of Study 1 suggested that a whole-body movement screen could be used to identify personal characteristics that constrain movement behaviour in ways that impact occupational low-back loading demands and injury potential. The purpose of this study was to examine if Functional Movement Screen™ (FMS) scores could be used to project the low-back loading response to lifting. Methods: Sagittally symmetric and asymmetric laboratory-based lifting tasks were performed by 15 firefighters who scored greater than 14 on the FMS (high-scorers) and 15 size-matched low-scorers (FMS < 14). A three-dimensional dynamic biomechanical model was used to calculate low-back loading demands, and lumbar spine posture was recorded when peak low-back compression was imposed. Results: Regardless of the task performed, there were no differences in peak L4/L5 joint compression (p ≥ 0.4157), anterior/posterior reaction shear (p ≥ 0.5645), or medial/lateral reaction shear (p ≥ 0.2581) loading demands between high- and low-scorers. At the instant when peak compression force was detected, lumbar spine deviation was not different between high- and low-scorers about the lateral bend (p ≥ 0.4215), axial twist (p ≥ 0.2734), or flexion/extension (p ≥ 0.1354) axes. Conclusions: Using the previously established musculoskeletal injury prediction threshold value of 14, the composite FMS score did not project the low-back loading response to lifting. Future attempts to modify or reinterpret FMS scoring are warranted given that several previous studies have revealed links between composite FMS scores and musculoskeletal complaints. STUDY 4: Movement- vs. Fitness-Centric Exercise – Firefighter Fitness, Whole-Body Movement Qualities, and Occupational Low-Back Loading Outcomes. Background: The impact of exercise on firefighter job performance and cardiorespiratory fitness has been studied extensively, but its effect on musculoskeletal loading remains less understood. The aim of this study was to compare various physical fitness, general movement quality, and low-back loading outcomes between groups of firefighters who completed fitness- or movement-centric exercise. Methods: Fifty-four firefighters participated and were assigned to a control (CON), fitness-centric exercise (FIT), or movement-centric exercise (MOV) group. Before and after 12 weeks of exercise, subjects performed a physical fitness test battery, the Functional Movement Screen™ (FMS), and laboratory-simulated firefighting tasks during which low-back loading demands were quantified. Results: FIT and MOV subjects exhibited statistically significant improvements in nearly all measures of physical fitness (i.e., body composition, cardiorespiratory capacity, muscular strength, power, endurance, and flexibility), but FMS scores and occupational low-back loading demands were not impacted in a consistent way across individuals. Conclusions: Improving physical fitness can enhance job performance and prevent cardiac events in firefighters, but it was not clear that 12 weeks of exercise would alter their occupational low-back loading demands. Given variability in individual responses, the short study duration, and limited number and nature of tasks examined, more research incorporating alternative biomechanical and statistical analyses is needed to better understand how individuals adapt to chronic exercise and what impact these adaptations have on occupational movement behaviours, low-back loading demands, and low-back loading capacity. SUMMARY and CONCLUSIONS: Results confirmed that fireground activities are potentially hazardous for low-back health, as simulated occupational low-back loading demands routinely exceeded recommended exposure limits in the studies performed. However, results also indicated that personal movement strategies – possibly influenced by body size, preference, gender, physical fatigue, or distal lower extremity joint dysfunction – could alter occupational low-back loading demands and injury potential. It could not be concluded that occupational low-back loading demands and injury potential would be consistently affected by short-term improvements in physical fitness, nor could the low-back loading response to lifting be projected by scoring above or below 14 on the Functional Movement Screen™. Future research is warranted to examine the low-back loading demands associated with performing non-fireground duties, as opportunities may exist to implement ergonomic strategies to control cumulative low-back loading exposures. Particular attention should be paid to the exercise and training practices of firefighters, as musculoskeletal injuries sustained during these activities are potentially avoidable and could reduce the capacity of the musculoskeletal system to withstand demands imposed during non-modifiable fireground operations.

Bakgrund: Många arbetsmiljöproblem kretsar kring psykosociala faktorer. Relationen mellan krav, kontroll och socialt stöd har betydelse för hälsan. Riskökning för psykiskt lidande ses när både lågt socialt stöd och låg kontroll upplevs. Arbetstid och bristande kontroll har visat samband med bl.a. gastrointestinala problem och sömnstörningar. Brandpersonal har ett farligt yrke och inom brandmannayrket finns många stressorer som påverkar hälsan. Få studier finns gällande brandpersonals upplevelse av krav, kontroll och stöd kopplat till stressrelaterade symtom i arbetet. Det är betydelsefullt att undersöka förekomst av detta, då ohälsa kan få konsekvenser för individen, arbetsgruppen och hela samhället. Syfte: Kartlägga förekomst av stressrelaterade symtom och samband med krav, kontroll och socialt stöd hos brandpersonal i Sverige. Metod: Studien var en del av en tvärsnittsundersökning gällande brandpersonals hälsa där 476 personer deltog. Korrelationsanalyser med Spearmans korrelationskofficient utfördes. Resultat: Låg förekomst av sömn- och magbesvär sågs hos brandpersonalen. Samband påvisades där krav och socialt stöd korrelerade med sömnbesvär och magbesvär. Sömnbesvär och magbesvär korrelerade signifikant. Kön korrelerade med magbesvär. Konklusion: Förekomsten av mag- och sömnbesvär var låg och deltagarna mådde relativt bra. Vidare forskning kring friskfaktorer hos brandpersonal samt fler studier med andra variabler jämfört med krav, kontroll och stöd behövs. / Background: Many health and safety problems revolve around psychosocial factors. The relationship between demand, control and social support affect our health. Increased risk for mental suffering exists when low social support and low control is experienced. Working hours and lack of control can be associated with gastrointestinal- and sleeping problems. Firefighters have a dangerous occupation and many stressors affect the firefighter´s health. Few studies have investigated demand, control and support linked to stress-related symptoms at work for firefighters, it is important to investigate this though it may affect the individual, workgroup and society. Purpose: Identify occurrence of stress related symptoms and their relationship with demand, control and social support in Swedish firefighters. Method: The study was part of a cross-sectional study of firefighter's health, 476 people attended. Correlation analyzes with Spearman's korrelationskofficiens was performed. Results: Low prevalence of sleep- and stomach problems was seen. Correlation was found where demand and social support correlated with sleep- and stomach problems. Sleep- and stomach problems correlated significantly. Gender and stomach problems also correlated. Conclusion: The incidence of sleep- and stomach problems was low and participants felt relatively good. Further research on health factors of firefighters and more studies with other variables compared with demand, control and support is needed.

BACKGROUND and OBJECTIVES: Low-back overexertion injuries represent a large proportion of fireground “strains, sprains and muscular pains” and are a leading cause of disability and early retirement in firefighters. Given the inherently hazardous and unpredictable nature of many fireground activities, it is often infeasible to implement “task-focused” ergonomic controls and there are limited options to accommodate injured firefighters. Accordingly, effective and practical “worker-focused” injury prevention approaches are needed. Toward this end, four studies were conducted to address the following global thesis objectives: 1) Examine the possible role that firefighters’ personal movement strategies could have on their occupational low-back loading demands and injury potential; and 2) Compare the effects of two different exercise approaches on firefighters’ occupational low-back loading demands and injury potential. STUDY 1: Low-Back Loading Demands during Simulated Firefighting Tasks – Inter-Subject Variation and the Impact of Fatigue and Gender. Background: Non-modifiable fireground duties are considered hazardous for low-back health, but personal movement strategies could modulate low-back loading demands and injury potential. Study objectives were to quantify low-back loading demands during simulated firefighting tasks and to examine the impact of fatigue and gender on the peak loading response. Methods: Ten men and 10 women performed a battery of laboratory-simulated firefighting tasks before and following repeated bouts of a fatiguing stair-climbing protocol. An EMG-assisted three-dimensional dynamic biomechanical model was used to compute peak L4/L5 joint forces during task performance. Results: Peak low-back loading demands varied considerably between subjects and tasks, but 70% of all loading variables examined were of greater magnitudes in male subjects and 40% of all loading variables were of lower magnitudes in both males and females after stair-climbing. Some inter-subject variation in low-back loading was attributed to body size differences, but between- and within-subject differences in movement strategies also contributed to low-back loading variability between subjects and over time. Conclusions: Results of this study suggest that characteristics of individuals, tasks performed, and physical fatigue may influence peak low-back loading demands and injury potential in firefighters. Despite considerable inter-subject variation in the internal low-back loading response to fixed external task and environmental constraints, opportunities to attenuate low-back loading demands through movement behaviour adaptations alone may be limited to only a subset of fireground activities. STUDY 2: Ankle Immobilization alters Lifting Kinematics and Kinetics – Occupational Low-Back Loading Demands and Potential for Injury. Background: Firefighters with lingering lower extremity functional impairments could be forced to move in ways that increase their potential for sustaining occupational low-back lifting injuries. The study objective was to examine the impact of unilateral ankle immobilization on lifting kinematics and kinetics. Methods: With and without their right ankle immobilized, 10 male volunteers performed laboratory-simulated occupational lifting tasks. Together with force platform data, three-dimensional kinematics of the lumbar spine, pelvis, and lower extremities were collected, and a three-dimensional dynamic biomechanical model was used to calculate peak low-back compression and shear loading demands. Results: In comparison to the unaffected conditions, ankle immobilization resulted in less knee (p-values between 0.0004 and 0.0697) and greater lumbar spine (p-values between 0.0006 and 0.3491) sagittal motion when lifting. Associated with this compensatory movement strategy were greater L4/L5 anterior/posterior reaction shear forces (p-values between 0.0009 and 0.2450). However, in a few cases where individual compensatory movement strategies differed from the “group” response (i.e., subjects increased their sagittal knee and hip motion on the affected side), peak L4/L5 joint compressive loads increased while the peak L4/L5 anterior-posterior shear did not change. Conclusions: Distal lower extremity joint dysfunction can alter the way in which individuals move and load their low-backs when lifting. The specific ways in which individuals compensate for personal movement constraints could alter the potential site and mechanism of occupational low-back injury. STUDY 3: FMS™ Scores and Occupational Low-Back Loading Demands – Whole-Body Movement Screening as an Ergonomic Tool? Background: Results of Study 1 suggested that a whole-body movement screen could be used to identify personal characteristics that constrain movement behaviour in ways that impact occupational low-back loading demands and injury potential. The purpose of this study was to examine if Functional Movement Screen™ (FMS) scores could be used to project the low-back loading response to lifting. Methods: Sagittally symmetric and asymmetric laboratory-based lifting tasks were performed by 15 firefighters who scored greater than 14 on the FMS (high-scorers) and 15 size-matched low-scorers (FMS < 14). A three-dimensional dynamic biomechanical model was used to calculate low-back loading demands, and lumbar spine posture was recorded when peak low-back compression was imposed. Results: Regardless of the task performed, there were no differences in peak L4/L5 joint compression (p ≥ 0.4157), anterior/posterior reaction shear (p ≥ 0.5645), or medial/lateral reaction shear (p ≥ 0.2581) loading demands between high- and low-scorers. At the instant when peak compression force was detected, lumbar spine deviation was not different between high- and low-scorers about the lateral bend (p ≥ 0.4215), axial twist (p ≥ 0.2734), or flexion/extension (p ≥ 0.1354) axes. Conclusions: Using the previously established musculoskeletal injury prediction threshold value of 14, the composite FMS score did not project the low-back loading response to lifting. Future attempts to modify or reinterpret FMS scoring are warranted given that several previous studies have revealed links between composite FMS scores and musculoskeletal complaints. STUDY 4: Movement- vs. Fitness-Centric Exercise – Firefighter Fitness, Whole-Body Movement Qualities, and Occupational Low-Back Loading Outcomes. Background: The impact of exercise on firefighter job performance and cardiorespiratory fitness has been studied extensively, but its effect on musculoskeletal loading remains less understood. The aim of this study was to compare various physical fitness, general movement quality, and low-back loading outcomes between groups of firefighters who completed fitness- or movement-centric exercise. Methods: Fifty-four firefighters participated and were assigned to a control (CON), fitness-centric exercise (FIT), or movement-centric exercise (MOV) group. Before and after 12 weeks of exercise, subjects performed a physical fitness test battery, the Functional Movement Screen™ (FMS), and laboratory-simulated firefighting tasks during which low-back loading demands were quantified. Results: FIT and MOV subjects exhibited statistically significant improvements in nearly all measures of physical fitness (i.e., body composition, cardiorespiratory capacity, muscular strength, power, endurance, and flexibility), but FMS scores and occupational low-back loading demands were not impacted in a consistent way across individuals. Conclusions: Improving physical fitness can enhance job performance and prevent cardiac events in firefighters, but it was not clear that 12 weeks of exercise would alter their occupational low-back loading demands. Given variability in individual responses, the short study duration, and limited number and nature of tasks examined, more research incorporating alternative biomechanical and statistical analyses is needed to better understand how individuals adapt to chronic exercise and what impact these adaptations have on occupational movement behaviours, low-back loading demands, and low-back loading capacity. SUMMARY and CONCLUSIONS: Results confirmed that fireground activities are potentially hazardous for low-back health, as simulated occupational low-back loading demands routinely exceeded recommended exposure limits in the studies performed. However, results also indicated that personal movement strategies – possibly influenced by body size, preference, gender, physical fatigue, or distal lower extremity joint dysfunction – could alter occupational low-back loading demands and injury potential. It could not be concluded that occupational low-back loading demands and injury potential would be consistently affected by short-term improvements in physical fitness, nor could the low-back loading response to lifting be projected by scoring above or below 14 on the Functional Movement Screen™. Future research is warranted to examine the low-back loading demands associated with performing non-fireground duties, as opportunities may exist to implement ergonomic strategies to control cumulative low-back loading exposures. Particular attention should be paid to the exercise and training practices of firefighters, as musculoskeletal injuries sustained during these activities are potentially avoidable and could reduce the capacity of the musculoskeletal system to withstand demands imposed during non-modifiable fireground operations.

Firefighters and asphalt pavers are exposed to polycyclic aromatic hydrocarbons (PAHs) during various work activities. The purpose of this study was to evaluate urinary PAH levels and compare these bio-monitoring levels among firefighters, asphalt pavers, and non-occupationally exposed individuals. The National Institute of Standards and Technology (NIST) urinary PAH levels were used for non-occupationally exposed controls. When compared to the NIST standard for smokers and non-smokers, firefighters demonstrated statistically significant differences in urinary concentration differences for the following metabolites: 2-OH-fluorene, 3-OH-fluorene and 1-OH-pyrene, which were lower in firefighters than the NIST mean for smokers. 1-OH-phenanthrene, 2-OH-phenanthrene and 3-OH-phenanthrene were higher among world trade center exposed firefighters than the NIST mean for smokers. When firefighters were compared to the NIST non-smoker standard, firefighters demonstrated elevated levels in all tested PAH biomarkers due to a mixture of smokers and non-smokers in the firefighter cohort. Asphalt workers had statistically significant higher urinary concentration elevations in 2-OH-fluorene, 1-OH-phenanthrene and 3-OH-phenanthrene as compared to the NIST smoker mean. When asphalt pavers were compared to the NIST non-smoker mean, asphalt pavers had statistically significant increases in all tested PAH biomarkers, with the exception of 2-OH-phenanthrene. While firefighters did not demonstrate a substantial change in urinary PAH metabolite levels compared to control populations of smokers and non-smokers, asphalt pavers experienced concentrations that were in some cases increased by orders of magnitude compared to NIST controls. Future research may be needed to evaluate any potential health risk posted to occupational exposed asphalt pavers.

The thesis deals with the reconstruction of L410UVP-E20 for firefighting needs. There is also an activity of aerial fire fighting services in the Czech Republic. The thesis also addresses the use of modifications for patrol work and for transporting the wounded.

Brandmansyrket har under lång tid varit mansdominerat, trots att antalet kvinnor inom yrket har ökat går det än idag att se en tydlig skillnad mellan antalet kvinnliga respektive manliga brandmän. Med grund i denna problematik har denna studie syftat till att undersöka kvinnliga brandmäns upplevelser av kulturen i ett mansdominerat yrke. Studien har utgått ifrån frågeställningarna “Påverkas kulturen på arbetsplatsen av att det är ett mansdominerat yrke?” samt “Hur upplever kvinnliga brandmän att arbeta i ett mansdominerat yrke?”. För att undersöka detta har empiri samlats in genom kvalitativa intervjuer med nio kvinnliga brandmän. Med hjälp av Raewyn Connells teori om genusrelationer och hegemonisk maskulinitet samt Erving Goffmans begrepp taktfullhet, har det insamlade materialet analyserats. Intervjuerna har bidragit med förståelse för de kvinnliga brandmännens upplevelser av att arbeta i ett mansdominerat yrke. Resultatet har visat att de kvinnliga brandmännen har en positiv inställning till att arbeta i ett mansdominerat yrke samt att det har skett förändring i kulturen, men belyser vikten av en fortsatt utveckling av jämställdhetsarbetet. / For a long time firefighter has been a male dominated profession. Even though the number of female firefighters has increased there is still a distinct difference between the amount of female- and male firefighters. Based on this problem this study aimed to examine female firefighters experience of the culture in a male dominated profession. The framing questions of the study was ”Does the fact that it is a male dominated profession affect the culture in the workplace?” and ”How does female firefighters experience working in a male dominated profession?”. The study is of qualitative character and the empirical material has been collected through nine qualitative interviews with female firefighters. The empirical material has been analysed using Raewyn Connells Theory of gender realisations and hegemonic masculinity, as well as Erving Goffmans concept Tact. The interviews has contributed with understanding of the female firefighters experience of working in a male dominated profession. The results has shown that female firefighters has a positive attitude towards working in a male dominated profession and their experience is that there has been a change in the culture. Despite that they also highlight the importance of continued development of gender equality work.

Dans cette thèse, nous étudions la complexité algorithmique de problèmes d'optimisation impliquant un processus de diffusion dans un graphe. Plus précisément, nous nous intéressons tout d'abord au problème de sélection d'un ensemble cible. Ce problème consiste à trouver le plus petit ensemble de sommets d'un graphe à “activer” au départ tel que tous les autres sommets soient activés après un nombre fini d'étapes de propagation. Si nous modifions ce processus en permettant de “protéger” un sommet à chaque étape, nous obtenons le problème du pompier dont le but est de minimiser le nombre total de sommets activés en protégeant certains sommets. Dans ce travail, nous introduisons et étudions une version généralisée de ce problème dans laquelle plus d'un sommet peut être protégé à chaque étape. Nous proposons plusieurs résultats de complexité pour ces problèmes à la fois du point de vue de l'approximation mais également de la complexité paramétrée selon des paramètres standards ainsi que des paramètres liés à la structure du graphe. / In this thesis, we investigate the computational complexity of optimization problems involving a “diffusion process” in a graph. More specifically, we are first interested to the target set selection problem. This problem consists of finding the smallest set of initially “activated” vertices of a graph such that all the other vertices become activated after a finite number of propagation steps. If we modify this process by allowing the possibility of ``protecting'' a vertex at each step, we end up with the firefighter problem that asks for minimizing the total number of activated vertices by protecting some particular vertices. In fact, we introduce and study a generalized version of this problem where more than one vertex can be protected at each step. We propose several complexity results for these problems from an approximation point of view and a parameterized complexity perspective according to standard parameterizations as well as parameters related to the graph structure.

Wildland fire behavior research in the last 100 years has largely focused on understanding the physical phenomena behind fire spread and on developing models that can predict fire behavior. Research advances in the areas of live-fuel combustion and combustion modeling have highlighted several weaknesses in the current approach to fire research. Some of those areas include poor characterization of solid fuels in combustion modeling, a lack of understanding of the dominant heat transfer mechanisms in fire spread, a lack of understanding regarding the theory of live-fuel combustion, and a lack of understanding regarding the behavior of flames near slopes. In this work, the physical properties, chemical properties and burning behavior of the foliage from ten live shrub and conifer fuels were measured throughout a one-year period. Burn experiments were performed using different heating modes, namely convection-only, radiation-only and combined convection and radiation. Models to predict the physical properties and burning behavior were developed and reported. The flame behavior and associated heat flux from fires near slopes were also measured. Several important conclusions are evident from analysis of the data, namely (1) seasonal variability of the measured physical properties was found to be adequately explained without the use of a seasonal parameter. (2) ignition and burning behavior cannot be described using single-parameter correlations similar to those used for dead fuels, (3) moisture content, sample mass, apparent density (broad-leaf species), surface area (broad-leaf), sample width (needle species) and stem diameter (needle) were identified as the most important predictors of fire behavior in live fuels, (4) volatiles content, ether extractives, and ash content were not significant predictors of fire behavior under the conditions studied, (5) broadleaf species experienced a significant increase in burning rate when convection and radiation were used together compared to convection alone while needle species showed no significant difference between convection-only and convection combined with radiation, (6) there is no practical difference between heating modes from the perspective of the solid—it is only the amount of energy absorbed and the resulting solid temperature that matter, and (7) a radiant flux of 50 kW m-2 alone was not sufficient to ignite the fuel sample under experimental conditions used in this research, (8) the average flame tilt angle at which the behavior of a flame near a slope deviated from the behavior of a flame on flat ground was between 20° and 40°, depending on the criteria used, and (9) the traditional view of safe separation distance for a safety zone as the distance from the flame base is inadequate for fires near slopes.