Network coding refers to the implementation of coding methods to utilize network connections more efficiently. Network coding is commonly researched in the information theory field, but very little research is being done on the physical implementation thereof. One exception is COPE where network coding is implemented in wireless networks for unicast transmission sessions. In this dissertation, we discuss the physical arrangement of wireless nodes to form topologies suitable for the implementation of network coding. We implement linear network coding in wireless ad hoc networks for multicast transmission sessions. We calculate the areas in which each wireless node must be located for a specific network coding suitable topology to be formed. The identified topologies are simulated in OPNET Modeler and then implemented on a six node testbed, to analyse the effect of implementing network coding in these topologies. We provide results indicating the trade-off between reduced network load and higher end-to-end delay when our developed network coding algorithm is active in the respective topologies. The results indicate that the developed network coding scheme will produce better overall performance when implemented in sensor networks or highly congested ad hoc networks. / Thesis (M.Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011.

Network coding refers to the implementation of coding methods to utilize network connections more efficiently. Network coding is commonly researched in the information theory field, but very little research is being done on the physical implementation thereof. One exception is COPE where network coding is implemented in wireless networks for unicast transmission sessions. In this dissertation, we discuss the physical arrangement of wireless nodes to form topologies suitable for the implementation of network coding. We implement linear network coding in wireless ad hoc networks for multicast transmission sessions. We calculate the areas in which each wireless node must be located for a specific network coding suitable topology to be formed. The identified topologies are simulated in OPNET Modeler and then implemented on a six node testbed, to analyse the effect of implementing network coding in these topologies. We provide results indicating the trade-off between reduced network load and higher end-to-end delay when our developed network coding algorithm is active in the respective topologies. The results indicate that the developed network coding scheme will produce better overall performance when implemented in sensor networks or highly congested ad hoc networks. / Thesis (M.Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011.

Urban sprawl är ett problem i hela världen. Ekonomi, hälsa, miljö och jordbruksmark är några saker som stadsutbredningen har effekter på (Habibi, 2011). I USA började problemen med urban sprawl efter andra världskriget när möjligheter till billiga bolån skapades. Detta gjorde att fler människor hade möjlighet att flytta till enfamiljshus i förorterna och användandet av bil som transportmedel ökade (Duany, 2010). Stadsutbredningen i Sverige startade efter andra världskriget då bilismen ökade även här. Den svenska trafikplaneringen var influerade av den nordamerikanska planeringsmodellen med resultatet att boendetätheten minskade med upp emot en tredjedel (Svenska Naturskyddsföreningen, 2006).     Det finns en hel del metoder för att motarbeta och kontrollera stadsutbredningen. Exempel på metoder är förtätning och sätt att reducera och kontrollera trafik (Habibi, 2011) samt mer djupgående strategier som urban growth boundaries och green belts (Gennaoi et al, 2009).   Eftersom det finns väldigt lite information om urban sprawl i Sverige, så handlar detta arbete om att göra en fallstudie för att undersöka hur åtta svenska kommuner arbetar med att kontrollera och motverka urban sprawl. Dessa kommuner är Stockholm, Göteborg, Malmö, Uppsala, Västerås, Örebro, Linköping och Helsingborg. Kommunernas översiktsplaner har studerats med målet att påvisa fyra metoder för att motverka urban sprawl som identifieras av Habibi (2011).   Sverige är och har varit påverkat av urban sprawl (Svenska Naturskyddsföreningen, 2006). Undersökningen av översiktsplanerna i de svenska kommunerna visar också att alla arbetar mot en hållbar utveckling av sin stad genom förtätning och utbyggnad av kollektivtrafiken. Kommunerna använder sig av generella metoder som förtätning och kontroll av trafik men använder sig inte av några mer specifika och mer djupgående metoder som urban growth boundaries och green belts. Detta kan bero på flera saker, bland annat att de mer djupgående metoderna inte nämns av kommunerna i deras översiktsplaner utan istället kanske finns med i detaljplanerna.

This dissertation is about post-divorce families. The central question is how family is constructed after divorce. The aim is to study how family relationships are negotiated, transformed and reproduced after the separation. The research is based on 24 in-depth interviews with twelve young adults, between the ages of 21 and 29, with divorced parents. Their narratives about their families are analysed using a theoretical framework inspired by the individualization theories (Beck & Beck-Gernsheim 2001; Giddens 1997, 1995) and the doing family perspective (Morgan 1996; Silva & Smart 1999a), especially focusing on the concepts of negotiation and family practices. More specific questions raised in the dissertation are how are family boundaries drawn by the young adults? How do the interviewees understand the new organization of their families, which has been renegotiated after the separation? What perception of motherhood and fatherhood can be found in the narratives? And, finally, to what extent are family relationships after divorce negotiated in the way that the individualization theories claim? The results show a quite complex picture of family life after divorce. While both parents are often described as participating parents, the family practices after divorce appear clearly gendered. The mother’s involvement in taking care of the child seems not to be negotiable in the same way as the father’s. Hence, motherhood appears natural and taken for granted to a much greater extent than fatherhood. The negotiations between the parents after divorce can be of both an explicit and implicit character according to the narratives, but yet another kind of negotiation are the indirect negotiations. In these negotiations, the child is used as a go-between or carrier, a position that seems to limit their own possibility to participate in the decision making. Another aspect that seems to diminish children’s participation is the principle of loyalty to both their biological parents. The results also show that the children’s living arrangements after divorce are characterized by changes and renegotiations rather than being permanent. The parents’ new partners are described in different ways in the narratives, however, they are often seen as turning points that have a major influence on the family relationships. The nuclear family as a normative ideal is present in all the interviews but in different ways. While some express an explicit critique of it, others regard it as something that they want for themselves in the future. What constitutes a family according to the narratives? Firstly, blood ties and formal relationships are pointed out. Secondly, the feeling of solidarity and closeness is viewed perhaps as the most evident element of family life. This feeling can be created by open communication as well as by spending time together on a regular basis. Thirdly, growing up together and/or sharing everyday life practices are also considered as vital to develop and maintain close family ties. This means that the family boundaries after divorce are renegotiated over time rather than permanent. These negotiations take place in a certain context, where gender norms, earlier experiences and other social relationships play an important role.

This qualitative study is aimed to find out how teachers at one preschool relate to influence and boundaries. This has been carried out through qualitative interviews whose contents have been analyzed and processed. The theoretical framework of the study is the philosophy of John Dewey derived from Pragmatism, where thought and action is seen as one where the child needs to try and experiment to learn. We are two authors who stand for this study in which we both were present at all times for the interviews. The interviews revealed that teachers believe that influence is important for children's self-esteem, to become a good citizen of the community and to learn that certain things are expected. It also emerged that influence combined with boundaries is seen as very important. It appeared that the teachers look at influence in preschool in three different ways - influence here and now, influence in the future and influence for the children self-esteem. Overall, it appeared that the influence is seen as important in combination with boundaries.

The western part of the border between Mexico and the United States consists of two primary regions, Tijuana-San Diego and Mexicali-Calexico (Imperial Valley). Over the last fifteen years Mexicali has been one of the fastest-growing cities in Mexico in terms of industrial development, job creation, and energy demand, thus resulting in increased air pollution and environmental degradation. This air pollution has thus been linked to high rates of asthma and respiratory diseases on both sides of the border. This thesis focuses on pollutant formation and pollutant interactions between the three regions of the Mexicali-Imperial Valley (MC), Tijuana-San Diego (TS), and Los Angeles (LA) areas. The MODELS-3 modeling approach is used for analyzing the formation of secondary species, and transport of both primary and secondary pollutants between the regions during three pollution episodes in July 2001, August 2001, and January 2002. Area and mobile sources are identified as primary pollutant emitters in MC and TS regions. Source contribution from within the region and from other regions is conducted using CMAQ/ DDM. During the summer episode, O3 plumes originating from TS are transported eastwards along the border region towards MC. O3 plumes generated from precursors emitted by LA mobile sources are transported towards MC and add up to 10 ppbv in the MC region. O3 plumes reach the border regions of California-Arizona and O3 concentrations up to 4 ppbv in the Grand Canyon area can be attributed to area sources in the MC region. Contribution of up to 11 ppbv of O3 in Calexico-Mexicali can be attributed to the high density of vehicles in and around the San Diego region. During the winter episode, the winds being southeasterly (towards southeast) plumes from TS, LA and Las Vegas unite and move towards the MC region with impacts of 10-35 μg m-3. The soil dust contributions from LA, TS and MC range between 5-25 μg m-3. MC area sources contribute a maximum of 34 μg m-3 PM2.5.

The scale of the energy business today and a favorable and promising economic environment for the production of natural gas, requires study of the thermophysical behavior of fluids: sophisticated experimentation yielding accurate, new volumetric data, and development and improvement of thermodynamic models. This work contains theoretical and experimental contributions in the form of 1) the revision and update of a field model to calculate compressibility factors starting from the gross heating value and the mole fractions of diluents in natural gas mixtures; 2) new reference quality volumetric data, gathered with state of the art techniques such as magnetic suspension densimetry and isochoric phase boundary determinations; 3) a rigorous first-principles uncertainty assessment for density measurements; and 4) a departure technique for the extension of these experimental data for calculating energy functions. These steps provide a complete experimental thermodynamic characterization of fluid samples. A modification of the SGERG model, a standard virial-type model for prediction of compressibility factors of natural gas mixtures, matches predictions from the master GERG-2008 equation of state, using least squares routines coded at NIST. The modification contains new values for parametric constants, such as molecular weights and the universal gas constant, as well as a new set of coefficients. A state-of-the-art high-pressure, single-sinker magnetic suspension densimeter is used to perform density measurements over a wide range of temperatures and pressures. This work contains data on nitrogen, carbon dioxide, and a typical residual gas mixture (95% methane, 4% ethane, and 1% propane). Experimental uncertainty results from a rigorous, first-principles estimation including composition uncertainty effects. Both low- and high-pressure isochoric apparatus are used to perform phase boundary measurements. Isochoric P-T data can determine the phase boundaries. Combined with density measurements, isochoric data provides isochoric densities. Further mathematical treatment, including noxious volume and thermal expansion corrections, and isothermal integration, leads to energy functions and thus to a full thermodynamic characterization.

Uppsatsen handlar om inhyrda lärares arbetssituation som befinner sig utanför organisationers gränser vilket leder till exkludering och bristfälliga arbetsvillkor. Inhyrd personal befinner sig i en trepartsrelation mellan sig själv, bemanningsföretag och kundföretag. Detta skulle kunna göra att den formella tillhörigheten och känslan av tillhörighet differentieras. Inget i studien tyder på att de inhyrda lärarna inte känner en tillhörighet till bemanningsföretaget som arbetsgivare och därmed kan vi inte dra slutsatsen att detta är problemet. Snarare är det kundföretaget och dess medarbetare som inte ser de inhyrda lärarna som inkluderade i organisationen vilket skapar exkludering. Dagens företag behöver vara flexibla och för att möta detta behov används inhyrd personal som en tillfällig resurs. Bemanningsföretag växer sig allt starkare och studien är viktig för att visa att anställningsformen kan få negativa konsekvenser och att man bör ta hänsyn till emotionella aspekter hos individen. Studien är kvalitativ och har genomförts genom djupintervjuer med tre inhyrda lärare, tre ordinarie lärare och en rektor. Då ämnet kan ses som känsligt av vissa parter är ämnet något svårstuderat och det har varit svårt att få tag på intervjupersoner. Materialet har analyserats med teorier utifrån tre teman: tillhörighet, trygghet och frihet vilka följer som en röd tråd genom uppsatsen. / This essay examines temporary teachers working situation and the findings show that they fall outside organizations’ boundaries which leads to exclusion and poor working conditions. The temporary teachers exist in a trilateral relationship between them self, temporary work agencies and client companies. This could make the formal affiliation and sense of belonging differentiated. Nothing in the study suggests that the hired temporary teachers do not feel an affinity to the temporary work agency and thus we cannot conclude that this is the problem. The issue is rather that the client company and its employees do not see the hired temporary teachers as included within the organization. This creates exclusion. The temporary work agencies are growing stronger and this study is important since it highlights that the form of employment can have negative consequences and that the emotional aspects of the individual should be taken into account. The study is qualitative and has been executed by performing in-depth interviews. Due to the delicate nature of the subject to some parties the topic is somewhat difficult to study. Furthermore, it has been difficult to get hold of the people interviewed. The empirical data was analysed with theories based on three themes: belonging, security and freedom.

Small back-barrier sand islands are poorly known in terms of hydrogeology and have been overlooked in more extensive studies of coastal groundwater systems that include larger barrier island complexes. This study employs a three-fold sequential approach to aquifer characterisation in a back-barrier sand island. A three-dimensional stratigraphic model forms the foundation framework, being derived from a multidisciplinary approach to sedimentary analysis and the construction of a depositional chronology. A conceptual hydrostratigraphic model is formulated based on the translation of sedimentary facies to hydrofacies, combined with density dependent flow calculations and tidal oscillation measurements. Groundwater hydrochemical data and mineral geochemistry are integrated with the resulting hydrogeological model to examine water-rock interaction and solute transport mechanisms. The study area is Toorbul Island, a small back-barrier sand mass of ~5 km2 with a maximum surface elevation of ~3.5 m AHD, located in the Pumicestone Passage of Southeast Queensland. The island hosts a dual aquifer system consisting of an unconfined island freshwater lens, underlain by a semi-confined palaeovalley-fill aquifer. Groundwater in the semi-confined aquifer is hyper-saline, carrying high concentrations of dissolved metals, with iron, in particular, ranging from 40 to < 200 mg l-1. This is of significant interest for both human health and environmental management, because iron is an important nutrient source for toxic algal bacteria such as Lyngbya majuscula. Conceptual modelling demonstrates that iron oxides and hydroxides are the main source of iron in the semi-confined aquifer, with a contribution from ferruginous chlorite dissolution. Aqueous manganese and a proportion of the aqueous iron are derived from the dissolution of manganoan ilmenite. Ferric iron minerals also contribute a significant proportion of dissolved iron in the deeper regions of the unconfined aquifer. Aqueous iron in the shallow unconfined groundwater is limited by iron sulphides, which also regulate acidity and indirectly limit dissolved aluminium concentrations. Groundwater redox state governed by seasonal climatic fluxes is the most significant control on iron-bearing mineral phase stability. Transport of dissolved metals to the surrounding estuary and the adjacent barrier island groundwater system is limited by the rate of ion diffusion across transition zone boundaries. The overall conclusions derived from this research show that back-barrier islands should be evaluated as discrete hydrogeological entities. The stratigraphic complexity that may be apparent within these island landforms should not be underestimated and the model domain should not necessarily be treated as a homogeneous system. This complexity is exemplified by the relationship between the upper and lower aquifers on Toorbul Island and the associated distribution of groundwater compositional heterogeneity. The complex stratigraphy within the sedimentary pile is derived from the presence of a sub-surface palaeovalley and the sedimentary response to changing sea-level over time. Considering the current widespread distribution of estuarine systems, complex hydrogeology as exhibited by Toobul Island, may be common in many small back-barrier island groundwater systems. The aquifer characteristics and their influence on solute transport and delivery can have significant ramifications for the exploitation of the adjacent coastal plain and barrier island aquifers. The potential influence on the latter is of particular concern due to the pressure imposed on potable groundwater supplies by increasing population densities in coastal areas.

The home is a material place of routine and isolation. Cyberspace, on the other hand, is associated with the lightness of disembodiment and engagement with others in virtual worlds. I am interested in the home as a locale of cyberspace in regard to the relationship between attaching and detaching, territorializing and de-territorializing, the smooth and the striated. My experimentation is about frozen moments in day-to-day situations. Through experiments with light, materials and installations, I intend to draw out a tactile perspective on cyberspace and domesticity. In terms of materials, I am particularly interested in the residues in everyday life. Light and materials are considered to be tactile as well as visual. Performativity, Heuristics and Active Documentation are my main methodological approaches. My work does not seek to fix a solution, but open up an area of ongoing discovery. The physical makings are the ignition for later developments. Once the installation has been set up, the performativity is transferred to the audience. The surrounding space becomes activated because of the energy released by the audience's engagement. Heuristic use of intuition and informal experience was applied in my working process to discover imperceptible traits of materials and daily situations. Active Documentation helps me to re-consider, re-negotiate, reflect and renew my work throughout the project. In this way, hidden codes can be brought out to the surface.