Energy demand in the built environment is quite important. China holds a large population and the energy use in the building sector is about 1/3. The rebuilding of old houses and building new low energy houses are becoming more and more popular in China. Low energy building not only consumes less energy, but also provides good indoor environment. An indoor climate software IDA is used in energy and indoor climate simulation. The traditional high isolated low energy house in a hot climate is analyzed, on a typical day in either summer or winter, or during the whole year. Energy consumptions under different parameters are presented. Results show that high isolated house may not always be suitable in a hot climate.

Includes bibliographical references (p. 118-122).

Wireless communication is becoming more common, a relatively new technology within the area is Bluetooth Low Energy. It’s been developed to be energy efficient and in regard to compatibility. Alongside the growth of wireless technology, scientists and companies are looking for new areas of use. One of these is localization, which means to determine the position of a moving device with the use of stationary devices, an example of this would be GPS.This report means to evaluate indoor localization using Bluetooth Low Energy and was made for Combitech AB in Jönköping. The purpose of the work was to determine with what accuracy and precision the position of a moving device could be estimated. The report will answer the following questions: With what accuracy and precision can the position of a device be determined within a test area of varying size using Bluetooth Low Energy? Is the accuracy and precision affected by the environment?The authors chose an inductive reasoning and therefore intended to answer the questions with the help of experimental studies. A system consisting of both software and hardware was developed and was then used to conduct multiple rounds of tests, where the size of the area and the environment was varied.By evaluating the data gathered from said tests and comparing it to theoretical studies and prior research credible results were obtained. The accuracy appears to decrease as the distance between the units is increased, however a deeper analysis shows that the difference is smaller below 500 cm. No correlation is found between environment and accuracy. When three stationary units, forming a triangle with 400 cm between the vertices, are used to determine the position of a fourth the achieved accuracy is 65 cm. During the tests the precision is not shown to decrease with distance, it seems to vary independently. However, as the environment is changed a noticeable difference is observed. In a gymnasium the standard deviation was calculated to 0.38 RSSIwhereas in an office environment it was 0.99 RSSI. In regard to the given results the authors conclude that Bluetooth Low Energy shows some potential for the use in indoor positioning systems. A possible scenario where the technology would be well suited would be when the units need to work of a coin cell battery for a large period of time, while the system must support multiple types of units and a rough estimation of the position is adequate. / Trådlös kommunikation blir allt mer vanlig i vår vardag, en relativt ny teknik inom detta område är Bluetooth Low Energy som utvecklats med avseende på energieffektivitet och kompabilitet. Parallellt med den trådlösa teknikens spridning letar forskare, såväl som företag, efter nya användningsområden. En av dessa är lokalisering, vilket innebär att med fasta enheter avgöra rörliga enheters position, ett exempel på detta är GPS. Detta arbete handlar om att utvärdera inomhuslokalisering med Bluetooth Low Energy och gjordes på uppdrag av Combitech AB i Jönköping. Syftet var att undersöka med vilken noggrannhet och precision en rörlig enhets position kunde avgöras. Rapporten kommer att besvara följande frågeställningar: Med vilken noggrannhet och precision kan man med Bluetooth Low Energy avgöra en enhets position inom ett testområde med varierande storlek? Påverkas noggrannhet och precision av omgivningen?Författarna valde en induktiv metod och ämnade därför besvara frågeställningarna med hjälp av experimentella studier. Ett testsystem bestående av hård- samt mjukvara utvecklades varpå tester utfördes i flera omgångar, där storlek på område och omgivning varierades. Genom utvärdering av testdata i förhållande till teoretiska studier och tidigare forskning kunde trovärdiga resultat nås. Noggrannheten tycks minska då avståndet mellan enheter ökas, djupare analys pekar på en mindre förlust under 500 cm. Det observeras dock inget samband mellan noggrannhet och omgivning. Då tre fasta enheter placeras med ett inbördes avstånd på 400 cm kan positionen avgöras med 65 cm noggrannhet. Precisionen påverkas under testerna inte av avstånd, signalstyrkevärdena varierar helt oberoende av detta. Vid skifte av omgivning tydliggörs dock en markant skillnad i resultat. I en idrottshall beräknades standardavvikelsen till 0,38 RSSI medan den i en kontorsmiljö var 0,99 RSSI.Författarna drar utifrån det uppnådda resultat slutsatsen att Bluetooth Low Energy har viss potential att användas för inomhuslokalisering. Exempel på ett möjligt scenario där tekniken anses väl lämpad är då de fasta enheterna måste drivas av knappcellsbatterier under en lång tidsperiod, att systemet skall stödja en mängd olika enheter samt att en grov uppskattning av position är tillräcklig.

Zinc oxide surfaces have been of considerable interest because of their favorable properties, such as high electron mobility, good transparency, large electronic breakdown field and wide bandgap. Knowing the surface structure of ZnO is the key to better understand the above phenomena and to further develop its applications. In this thesis, the Patterson Function was evaluated by inversion of LEED I-V spectra at multiple incident angles to determine the surface structure of the ZnO(0001) polar surface. The sample was prepared by degassing and then 15 cycles of argon sputtering and annealing. The experimental LEED I-V spectra from multiple incident angles were taken from the sample. After processing the data by a macro program in OPTIMAS and a Matlab program, a clean Patterson Function map showing the inter-atomic pair distances was obtained. It was then compared with the simulated Patterson Function map of the proposed 1×1 bare surface model. As a result, the spots positions in the simulated Patterson Function map matched well with that of the experimental Patterson Function map. On the other hand, the LEED I-V curve fitting work was done by the surface science group of City University of Hong Kong. Six models were proposed by them and normal incidence theoretical LEED I-V spectra were calculated to fit with the experimental LEED I-V curves provided by us. Among the six models 2×2 Zn point defect model was fitted to be the best model with the R-factor 0.244. We also compared the multiple scattering simulated Patterson Function map of 2×2 Zn point defect model with the experimental one to verify the validity of the model. As a result, the model fit the experimental data. So we conclude that in general 1×1 model support the order part, and 2×2 top layer Zn defect model best fits the random missing part. / published_or_final_version / Physics / Master / Master of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

Στην παρούσα διατριβή παρουσιάζονται μεθοδολογίες σχεδιασμού που επιτρέπουν την μείωση την κατανάλωση ενέργειας σε υλοποιήσεις ασύρματων εφαρμογών πολυμέσων. Οι προτεινόμενες μεθοδολογίες βελτιστοποιούν την διαχείριση της μνήμης, η κατανάλωσης της οποίας είναι η κυρίαρχη συνιστώσα της συνολικής κατανάλωσης ισχύος στις εφαρμογές πολυμέσων. Επιπλέον, η διατριβή πραγματεύεται τεχνικές για χαμηλής κατανάλωσης διαμερισμό, ο οποίος είναι απαραίτητος για την εκτέλεση σε πραγματικό χρόνο των υψηλής υπολογιστικής πολυπλοκότητας εφαρμογών πολυμέσων. Στόχο της παρούσας διατριβής αποτελεί και η βελτιστοποίηση, όσον αφορά την κατανάλωση ισχύος, των κυκλωμάτων ασύρματης μετάδοσης των πολυμέσων. Στο πλαίσιο αυτό η διατριβή ασχολείται με τεχνικές διαχείρισης ισχύος, και προτείνει υλοποιήσεις που χρησιμοποιούν τις τεχνικές αυτές. Οι μεθοδολογίες και τεχνικές λαμβάνουν υπόψη και την επιφάνεια ολοκλήρωσης και ταχύτητα εκτέλεσης. Τα ισοζύγια (trade-offs) αναγνωρίζονται, και όπου αυτά υπάρχουν προτείνονται μέθοδοι για την αποδοτική τους επίλυση. / In this Ph.D. dissertation, design methodologies that enable energy minimization of wireless multimedia application realizations are presented. The proposed methodologies mainly optimize the management of the memory subsystem, which role is dominant as far as energy dissipation of multimedia application is concerned. Furthermore, techniques for the low-power partitioning, which is required for the real-time implementation of the highly computational complex multimedia applications, are proposed. Apart from the multimedia processing itself the dissertation, also focuses on the transmition of the multimedia content. To this end, power management techniques applicable for the design of wireless receivers are proposed. The proposed techniques are employed for the design of real-life implementation of low and medium rate receivers. Apart from energy minimization The proposed methodologies and techniques take into account constraints regarding the integration area as well as the processing time. The involved trade-offs are identified, and methods for their efficient exploration are proposed

This thesis investigates the application of low energy electron irradiation to 1,3,5-trimethylbenzene films to test whether site-selective C–H bond cleavage can be achieved in a molecule presenting both aliphatic and aromatic target sites. IRRAS was used to characterize the orientation of vapour-deposited 1,3,5-trimethylbenzene on Au(111) and alkanethiolated gold under UHV and cryogenic conditions. On both substrates, the disordered as-deposited films were transformed by thermal treatment, producing two film structures – within the first 4-monolayers, aromatic rings lie nearly parallel to the metal surface, while molecules in additional layers are more upright. Low energy electron irradiation (0-10 eV) produced no dissociations in 1,3,5-trimethylbenzene; however, low energy electron transmission spectra indicate charge accumulates at interstitial sites in the mesitylene film, decelerating subsequent incident electrons. These decelerated electrons traverse the charged film and are reaccelerated, inducing dissociations in the underlying SAM. Contrary to literature claims, 1,3,5-trimethylbezene is a poor molecule for adsorption studies such as BET as the initial adsorption is disordered and thermodynamically unstable.

No description available.

No description available.