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ABSTRAKTMål: Syftet med denna studie var att bestämma kariesprevalensen (ECC) hos 2-4åriga barn i utvalda områden i Kirikkale, Turkiet, och undersöka associationen tillmoderns S.mutansnivå. Det undersöktes möjliga samband mellan barnens S.mutans nivå och förekomst av ECC. Utöver det valdes även att undersökasambandet mellan riskfaktorer och barnens kariesprevalens samt samband mellanriskfaktorer och barnens S. mutansnivå.Metoder: En pilotstudie bestående av kliniska undersökningar och frågeformulärutformades för insamling och bearbetning av information. Studiepopulationenbestod av 60 barn mellan 2-4 år. De blev kliniskt undersökta för att bestämmaECC prevalensen. Mammors S. mutansnivåer jämfördes med barnens ECCprevalens.Resultat: ECC prevalensen var 45% och medelvärdet av karierade fyllda primäratänder (dft) var 2.1. Studien kunde inte visa något signifikant samband mellan S.mutansnivån hos mödrar och ECC förekomsten bland barn. Däremot visadestudien en signifikant relation mellan barnens ålder och dft. Studien visade ingasamband mellan riskfaktorer och dft och ej heller någon association mellanriskfaktorer och barnets S.mutansnivå.Slutsats: Studien visar att ECC prevalensen är relativt hög (45 %) blandförskolebarn inom de utvalda områdena av Kirikkale, Turkiet. Studien har intekunnat finna något signifikant samband mellan S. mutansnivå bland mödrar ochbarnens ECC prevalens. I samstämmighet med andra tidigare studier, visade detockså att förekomsten av S. mutans bland förskolebarn är starkt knuten till ECC. / ABSTRACTObjectives: The aim of the study was to determine the early childhood caries(ECC) prevalence among 2-4 years old children in selected areas of Kirikkale,Turkey. The study aims to find the association between ECC among children andthe Streptococcus mutans (S.mutans) level in their mothers. The study should alsodetermine possible associations between risk factors and children’s dental caries,and the association between risk factors and children’s S.mutans level.Methods: This is a pilot study consisting of a clinical examination and aquestionnaire, designed to collect necessary data. The study population of 60children, aged 2-4 years old, whom have been clinically examined to determinethe ECC prevalence. The mothers’ S.mutans levels have been compared with theECC prevalence among the children.Results: The ECC prevalence was 45% and mean number of primary decayed-filled teeth (dft) 2.1. The study could not show any correlation between S.mutanslevels among mothers and ECC prevalence among children. However, the studyshowed a significant association between children’s age and dft. Furthermore, thestudy could not find any association between the different risk factors and dft, orchildren’s S.mutans levels.Conclusion: The current study suggests that ECC prevalence is relatively high(45%) among preschool children in selected areas of Kirikkale, Turkey. However,the study could not find any significant relationships between S.mutans levelsamong mothers’ and children’s ECC prevalence. In consistency with earlierstudies in the field, results also suggest that the presence of S. mutans amongpreschool children is strongly connected to ECC.

The coming years are expected to bring multiple challenges for all actors within the energy sector. For the Swedish utility company Tekniska verken AB, one of the upcoming tasks is to adapt their energy technologies to enable renewable, plannable and efficient heat and power production. At the same time as the share of renewable energy increases, the demand grows for technologies that can cover for the intermittency and align with policies and goals for sustainable energy. Part of Tekniska verken’s work is therefore focused on investigation of potential solutions for their heat and power production, that also agrees with the municipality’s vision to become “the World’s most resource efficient region”. One of the current projects within the area regards installation and tests of a of a biofueled top cycle (BTC) with high electric efficiency. The project is carried out together with the owner of the technology: Phoenix Biopower AB. This thesis is part of the pre-study to the pilot project, which is aimed to examine the feasibility of installing a pilot unit of the Phoenix Biopower BTC technology in Tekniska verken’s combined heat and power plant KV62, Linköping, Sweden. The thesis is meant to examine the site feasibility through evaluation of how the operation of KV62 will be influenced by the pilot unit’s operation. The work consists of a mapping of necessary interfaces between KV62 and the BTC pilot unit, followed by an assessment of the impact of the pilot unit on operation of KV62. The feasibility is evaluated with respect to operational limits of KV62 and the study includes both quantitative and qualitative evaluation of the impact from the interfaces between the two units. The study has special focus on the impact from the pilot´s flue gases on the flue gas handling system in KV62 which appeared to be a critical interface with respect to the operational limits. The resulting operational changes in this work indicate that the pilot unit can be installed and run in connection to KV62, but that normal operation of KV62 cannot be sustained during steady state operation of the BTC pilot. This is mainly due to the pilot unit’s load in terms of steam withdrawal, and additional heat to the heat recovery system, that cannot be fully managed with the current capacity for feedwater in KV62. However, there can still be potential solutions to run test campaigns of the BTC pilot simultaneously as KV62 delivers both heat and power. It should be taken into consideration that the pilot units’ behavior during transients are not investigated in this work and therefore need further investigation before a decision about the feasibility of the pilot unit installation can be made. Furthermore, some interfaces have multiple options for their placements, and therefore a detailed heat-and mass balance over KV62 would be suggested to investigate the effects of the symbiosis between the decided interface locations further. / Framtiden förväntas medföra många utmaningar för aktörer inom energisektorn, och för Tekniska verken i Linköping är en av de framtida utmaningarna att anpassa energisystemet till kraft- och värmetekniker som är förnybara, effektiva och planerbara. Samtidigt som andelen förnybara energikällor ökar, växer även behovet för energi som kan täcka för oregelbundenheten hos vind- och solkraft och samtidigt passa i Linköpings vision om att bli världens mest resurseffektiva region. En del av Tekniska verkens arbete är att utforska möjliga lösningar för deras framtida energisystem, och en gren i arbetet med forskning och utveckling är ett projekt med mål att bygga och testa en pilotanläggning av en biobränslebaserad toppcykel (BTC). Projektet genomförs tillsammans med teknologins ägare: Phoenix Biopower. Detta examensarbete är del av förstudien tillhörande pilotprojektet, som är ämnad att undersöka genomförbarheten i att installera en pilotanläggning av Phoenix Biopowers teknologi med ett av Tekniska verken i Linköpings kraftvärmeverk, KV62 som moderanläggning. Examensarbetet syftar till att undersöka projektets genomförbarhet genom utvärdering av hur driften av KV62 kommer påverkas av pilotenheten. Arbetet består av en kartläggning av nödvändiga gränssnitt mellan KV62 och BTC-piloten, vilket följs av en bedömning av pilotenhetens inverkan på driften av KV62. Genomförbarheten utvärderas med avseende på driftsgränser för KV62 och studien inkluderar både kvantitativ och kvalitativ utvärdering av pilotens påverkan på KV62 till följd av gränssnitten mellan de två enheterna. Studien har särskilt fokus på rökgasens gränssnitt, som visade sig kunna vara kritiskt med avseende på påverkan från pilotens rökgas på processerna i KV62. Resultatet från arbetet visar att det är möjligt att ansluta och driva pilotanläggningen vid KV62, men att normal drift av KV62 inte kan bibehållas vid drift av BTC-piloten, framförallt på grund av pilotanläggningens belastning genom uttag av ånga; som inte kan hanteras fullt ut av befintlig kapacitet för matarvatten, och tillskottet av effekt till rökgasstråket vid överhettarna. Innan en slutgiltig bedömning av BTC-pilotens genomförbarhet med avseende på påverkan på KV62 kan göras vore det lämpligt att genomföra en studie av påverkan på KV62 under pilotens transienter, samt en analys av värme- och massbalanser i KV62 för fastställda placeringar av gränssnitten.

För att nå framgångsrika offentliga upphandlingar inom exempelvis IT är det viktigt att förbereda upphandlingsprocessen genom att planera resurser, kartlägga och analysera behov, marknad och risker (Upphandlingsmyndigheten, u.å.). En litteraturstudie på området visar att UX designers roll i upphandlingsprocesser är otydligt beskriven. Istället har fokus traditionellt sett handlat om användbarhet inom it-produkter, och ansvariga för användarcentrerade designansatser har systemleverantören varit. Lite eller inget ansvar för användarnas behov har legat på den offentliga organisationen. Men litteraturen visar även att upphandlaren bör vara aktiv genom en användarcentrerad designprocess både i kravställningen och genom hela projektet för att nå lyckade offentliga upphandlingar. För att undersöka hur UX designers arbetar i offentliga upphandlingsprocesser idag har följande frågeställningar besvarats: 1. Vilken roll och vilket inflytande har UX designers på upphandlingsprocessen i offentliga upphandlingar idag? 2. Vad karaktäriserar UX designers arbete på anbudsgivarsidan respektive anbudstagarsidan i upphandlingsprocessen för offentliga organisationer? Resultatet från en intervjustudie och en dokumentgranskning visar att UX designers har en tydlig roll på båda sidor om upphandlingsförfarandet. Inflytandet på upphandlingssidan var stort men begränsat till val av lösningsförslag på anbudstagarsidan. Att se över arbetsprocesser i grunden, se till användarnas behov, kravställa efter funktion och behov istället för tekniska krav och vikten av tydlig kommunikation var det som karaktäriserade UXdesigners arbete på båda sidor om upphandlingsprocessen. / To reach successful public procurements in the IT area it’s important to prepare the procurement process by planning resources, to map out and analyze needs, markets and risks (Upphandlingsmyndigheten, u.å.). A study of the literature in the area shows that the role of the UX designer is vaguely described. Instead the focus has traditionally been on usability in IT products and those responsible for user-centered design approaches have been the system suppliers. Some or none of the responsibility for the user needs has belonged to the public organization. But the literature also shows that the procurer needs to be active through a user-centered design process both in the requirements phase and throughout the entire project to reach successful public procurements. To explore how UX designers work in public procurement processes today the following framing of questions have been answered: ● What role and what kind of impact have UX designers on the procurement process inpublic procurements today? ● What characterizes the work of UX designers on the procurer’s side respectively the tenderer's side in the procurement process for public organizations? The results of an interview study and a document review shows that UX designers have a clear role on both sides of the procurement procedure. The impact on the procurer side was great but limited to the choice of solution proposals on the tenderer side. Fundamentally reviewing work processes, looking after the needs of the users, setting requirements according to function and needs instead of technical requirements and the importance of clear communication were what characterized the work of UX designers on both sides of the procurement process.

In the sixth generation of wireless communication systems (6G), there exist multiple candidate enabling technologies that help the wireless network satisfy the ever-increasing demand for speed, coverage, reliability, and mobility. Among these technologies, reconfigurable intelligent surfaces (RISs) extend the coverage of a wireless network into dead zones, increase capacity, and facilitate integrated sensing and communications tasks by consuming very low power, thus contributing to energy efficiency as well. RISs are meta-material-based devices whose electromagnetic reflection characteristics can be controlled externally to cater to the needs of the communication links. Most ubiquitously, this comes in the form of adding a desired phase shift to an incident wave before reflecting it, which can be used to phase-align multiple incident waves to increase the strength of the signal at the receiver and provide coverage to an area that otherwise would be a dead zone. While this portrays an image of a dream technology that would boost the existing wireless networks significantly, RISs do not come without engineering problems. First of all, the individual elements do not exhibit ideal reflection characteristics, that is, they attenuate the incident signal in a fashion depending on the configured phase shift. This creates the phenomenon called "phase-dependent amplitude". Another problem caused by RISs is the channel estimation overhead. In a multiple-antenna communication system, the channel between two terminals is as complex as the product of the number of antennas at each end. However, when an RIS comes into the equation, the cascade of the transmitter-RIS and RIS-receiver channels has a complexity further multiplied by the number of RIS elements. Consequently, the channel estimation process to utilize the RIS effectively becomes more demanding, that is, more pilot signals are required to estimate the channel for coherent reception. This adversely affects the effective data rate within a communication system since more resources need to be spent for pilot transmission and fewer resources can be allocated for data transmission. While there exists some work on reducing the channel dimensions by exploiting the channel structure, this problem persists for unstructured channels. In addition, for the wireless networks using multiple RISs, a new kind of pilot contamination arises, which is the main topic of this thesis. In the first part of this thesis, we study this new kind of pilot contamination in a multi-operator context, where two operators provide services to their respective served users and share a single site. Each operator has a single dedicated RIS and they use disjoint frequency bands, but each RIS inadvertently reflects the transmitted uplink signals of the user equipment devices in multiple bands. Consequently, the concurrent reflection of pilot signals during the channel estimation phase introduces a new inter-operator pilot contamination effect. We investigate the implications of this effect in systems with either deterministic or correlated Rayleigh fading channels, specifically focusing on its impact on channel estimation quality, signal equalization, and channel capacity. The numerical results demonstrate the substantial degradation in system performance caused by this phenomenon and highlight the pressing need to address inter-operator pilot contamination in multi-operator RIS deployments. To combat the negative effect of this new type of pilot contamination, we propose to use orthogonal RIS configurations during uplink pilot transmission, which can mitigate or eliminate the negative effect of inter-operator pilot contamination at the expense of some inter-operator information exchange and orchestration. In the second part of this thesis, we consider a single-operator-two-RIS integrated sensing and communication (ISAC) system where the single user is both a communication terminal and a positioning target. Based on the uplink positioning pilots, the base station aims to estimate both the communication channel and the user's position within the indoor environment by estimating the angle of arrival (AoA) of the impinging signals on both RISs and then exploiting the system and array geometries to estimate the user position and user channels respectively. Although there is a single operator, due to the presence of multiple RISs, pilot contamination occurs through the same physical means as multi-operator pilot contamination unless the channel estimation process is parameterized. Since the communication links are considered to be pure line-of-sight (LOS), their structure allows the reduction of the number of unknown parameters. Consequently, the reduction of information caused by pilot contamination does not affect the channel estimation procedure, hence the pilot contamination is overcome. On the other hand, the position of the user is determined by intersecting the lines drawn along the AoA estimates. We adopt the Cramér-Rao Lower Bound (CRLB), the lower bound on the mean squared error (MSE) of any unbiased estimator, for both channel estimation and positioning. Our numerical results show that it is possible to utilize positioning pilots for parametric channel estimation when the wireless links are LOS. / <p>QC 20240416</p>

Yes / In order to improve the performance of the reverse osmosis (RO) desalination plant powered by photovoltaic (PV), two cooling systems were proposed in this study to cool the PV and preheating the RO feed water as well. In the cooling design (1), the cooling fluid flows in direct contact with the back surface of the PV through channels of half circular cross-sections. While in the design (2), it flows through channels of squar cross-sections fixed on the PV back surface. Two nano-fluids were also tested as cooling fluid: H2O/CuO and H2O/Al2O3, in addition to distilled water for the purpose of comparison. The effect of changing the weight concentration of the nano-fluid (0.05, 0.1, and 0.15%) on the PV performance was also investigated. The results showed that the PV integrated with the cooling design (1) achieves better performance compared to design (2) at all studied cooling fluids. The improvements in the electric efficiency of the PV integrated with design (1) reached 39.5, 34.8 and 27.3 % when CuO and Al2O3 nano-fluids and distilled water were used as cooling fluid, respectively, compared to the uncooled PV. Based on the obtained experimental results, the PV integrated with design (1) was selected to power the RO with H2O/CuO nano-fluid of weight concentration 0.15% and flow rate 0.15 kg/s being used as the coolant. The RO powered by the improved PV was tested at different salinities of brackish water when the preheating technique was implemented. The results showed that the proposed PV-RO desalination system produces 366 l/day when brackish water of salinity 3000 ppm was used.

Students are coming to school with myriad issues that teachers and schools cannot address alone. ecological systems theory posits that the environments with which a child comes into contact, either directly or indirectly, can impact her or his development (Bronfenbrenner, 1979). With the support of community partner organizations in the local community, community schools can effectively respond to students’ needs and help them navigate the interconnected web of environments. Through interviews, focus groups, and a document review, this cross-site case study explored the practices that are employed by community school leaders (school staff and employees of community partner organizations) at two pilot high schools in the Los Angeles Unified School District (LAUSD), to implement six guiding principles of community schools. The study also captured impacts of these practices through participants’ perceptions, documents, and the application of transformative leadership theory. The findings revealed that the pilot school model is a natural avenue for the community schools strategy, and that intentional practices and a shared vision by all stakeholders can result in transformative impacts on students and the school as a whole. District and school leaders could consider developing processes and systems for implementing a community schools strategy district-wide by providing funding for community school coordinators for school sites, working with school leaders to develop their shared decision-making skills, and leveraging the assets and resources of community partners.

The rapid growth in wireless communications has given rise to an increasing demand for channel capacity using limited bandwidth. Wireless channels vary over time due to fading and changing interference conditions. Typical wireless systems are designed by choosing a modulation scheme to meet worst case conditions and thus rely on power control to adapt to changing channel conditions. Adaptive modulation, however, exploits these channel variations to improve the spectral efficiency of wireless communications by intelligently changing the modulation scheme based on channel conditions. Necessarily, among the modulation schemes used are spectrally efficient modulation schemes such as quadrature amplitude modulation (QAM) techniques. QAM yields the high spectral efficiency due to its use of amplitude as well as phase modulation and therefore is an effective technique for achieving high channel capacity. The main drawbacks of QAM modulation are its reduced energy efficiency (as compared to standard QPSK) and its sensitivity to channel amplitude variations. Adaptive modulation attempts to address the first drawback by using more energy efficient schemes in low SNR conditions are reserving the use of QAM for high SNR conditions. The second drawback leads to a requirement of high quality channel estimation. Many researchers have studied pilot symbol assisted modulation for compensating the effects of fading at the receiver. A main contribution of this thesis is the investigation of different channel estimation techniques (along with the effect of pilot symbol spacing and Doppler spread) on the performance of adaptive modulation. Another important parameter affecting adaptive modulation is the signal-to-noise ratio. In order to adapt modulation efficiently, it is essential to have accurate knowledge of the channel signal-to-noise ratio. The performance of adaptive modulation depends directly on how well the channel SNR is estimated. The more accurate the estimation of the channel SNR is, the better the choice of modulation scheme becomes, and the better the ability to exploit the variations in the wireless channel is. The second main contribution of this thesis is the investigation of the impact of SNR estimation techniques on the performance and spectral efficiency of adaptive modulation. Further, we investigate the impact of various channel conditions on SNR estimation and the resulting impact on the performance of adaptive modulation. Finally, we investigate long term SNR estimation, its use in adaptive modulation and present a comparison between the two approaches / Master of Science