Can a Leopard Change His Spots?: Child Custody and Batterer’s Intervention

Enabling multiple base stations to utilize the spatial dimension in a coordinated manner has been shown to be a fruitful technique for improving the spectral efficiency in wireless interference networks. This thesis considers multicell systems where base stations and mobile stations are equipped with multiple antennas. The base stations coordinate their spatial precoding, but individually serve their mobile stations with data. For such coordinated precoding systems, interference alignment (IA) is a useful theoretical tool, due to its ability to serve the maximum number of interference-free data streams. Three topics related to interference alignment and coordinated precoding are studied. First, the feasibility of IA over a joint space-frequency signal space is studied. A necessary condition for space-frequency IA feasibility is derived, and the possible gain over space-only IA is analyzed. An upper bound on the degree of freedom gain is shown to increase in the number of subcarriers, but decrease in the number of antennas. Numerical studies, using synthetically generated channels and real-world channels obtained from indoors and outdoors channel measurements, are used for sum rate performance evaluation. The results show that although a degree of freedom gain is noticeable due to the space-frequency precoding, the sum rate of the system is mainly improved due to a power gain. Second, distributed channel state information (CSI) acquisition techniques are proposed, which provide estimates of the information necessary to perform distributed coordinated precoding. The methods are based on pilot-assisted channel estimation in the uplink and downlink, and correspond to different tradeoffs between feedback and signaling, backhaul use, and computational complexity. Naively applying the existing WMMSE algorithm for distributed coordinated precoding together with the estimated CSI however results in poor performance. A robustification of the algorithm is therefore proposed, relying on the well known diagonal loading technique. An inherent property of the WMMSE solutions is derived and, when enforced onto solutions with imperfect CSI, results in diagonally loaded receive filters. Numerical simulations show the effectiveness of the proposed robustification. Further, the proposed robustified and distributed WMMSE algorithm performs well compared to existing state-of-the-art robust WMMSE algorithms. In contrast to our approach, the existing methods however rely on centralized CSI acquisition. Third, coordinated precoding systems with hardware impairments are studied. Assuming that impairment compensation techniques have been applied, a model is used to describe the aggregate effect of the residual hardware impairments. An iterative resource allocation method accounting for the residual hardware impairments is derived, based on an existing resource allocation framework. Numerical simulations show that the proposed method outperforms all benchmarks. In particular, the gain over impairments-aware time-division multiple access is substantial.Genom att låta flera radiobasstationer samarbeta är det möjligt att förbättra spektraleffektiviteten i trådlösa interferensnätverk. Fokus i denna licentiatavhandling ligger på multicellnätverk där både radiobasstationer och mobilenheter har flera antenner. Radiobasstationerna väljer sina spatiella förkodare gemensamt, men skickar data individuellt till sina respektive mobilenheter. För sådana system med koordinerad förkodning ('coordinated precoding') är interferensupprätning ('interference alignment') ett användbart teoretiskt verktyg, eftersom det möjliggör överföring av maximalt antal dataströmmar i nätverket. I avhandlingen studeras tre aspekter av interferensupprätning och koordinerad förkodning. Först undersöks interferensupprätning när signalrummet består av en kombination av rymd- och frekvensdimensioner. Ett nödvändigt villkor härleds för existensen av rymd/frekvens-interferensupprätning, och prestandavinsten analyseras i jämförelse med system där enbart rymddimensionerna används för interferensupprätning. Det föreslagna systemet utvärderas med hjälp av numeriska simuleringar och uppmätta inomhus- och utomhuskanaler. Resultaten visar att rymd/frekvens-interferensupprätning ger upphov till ett ökat antal frihetsgrader, men att summadatatakten främst förbättras tack vare en upplevd effektförstärkning. Därefter undersöks tekniker för skattning av den nödvändiga kanalkännedom som krävs för att genomföra koordinerad förkodning. Det finns flera sätt att erhålla den nödvändiga informationen, t.ex. genom olika kombinationer av kanalskattning, feedback, signalering och användning av backhaulnätverk. Speciellt söks distribuerade metoder, eftersom dessa är fördelaktiga vid praktisk implementering. Tre metoder för skattning av kanalkännedom föreslås. Dessa motsvarar olika avvägningar mellan kanalskattning och signalering, och en av metoderna är helt distribuerad. När den skattade informationen används med en existerande algoritm för koordinerad förkodning blir prestandan undermålig. Därför föreslås två förändringar av algoritmen, vilka leder till mer robusta prestanda. Förändringarna bygger på den välkända diagonal loading-tekniken. Utvärdering av det föreslagna systemet, som består av distribuerad erhållning av kanalkännedom samt den förbättrade algoritmen för koordinerad förkodning, genomförs med numerisk simulering. Resulterande prestanda är i nivå med ett tidigare föreslaget system, som dock kräver centraliserad tillgång till kanalskattningarna, till skillnad från vår nya lösning. Slutligen studeras ett system med koordinerad förkodning och icke-perfekt radiohårdvara. En modell för distortionsbruset orsakad av bristerna i radiohårdvaran används, och en iterativ resurstilldelningsteknik föreslås baserad på ett existerande ramverk. Den föreslagna algoritmen kan implementeras distribuerat över mobilenheterna, men kan i allmänhet inte implementeras distribuerat över radiobasstationerna. Den föreslagna algoritmen utvärderas med numeriska simuleringar, och resultaten visar att prestanda är bättre än alla referensmetoder. Detta visar betydelsen av att hantera bristerna i radiohårdvaran i resurstilldelningen. Sammantaget visar avhandlingen på möjligheterna att öka spektraleffektiviteten i framtida multicellnätverk med hjälp av koordinerad förkodning.QC 20140512</p

Heat transparent high intensity high efficiency solar cell

An improved solar cell design is described. A surface of each solar cell has a plurality of grooves. Each groove has a vertical face and a slanted face that is covered by a reflecting metal. Light rays are reflected from the slanted face through the vertical face where they traverse a photovoltaic junction. As the light rays travel to the slanted face of an adjacent groove, they again traverse the junction. The underside of the reflecting coating directs the light rays toward the opposite surface of solar cell as they traverse the junction again. When the light rays travel through the solar cell and reach the saw toothed grooves on the under side, the process of reflection and repeatedly traversing the junction again takes place. The light rays ultimately emerge from the solar cell. These solar cells are particularly useful at very high levels of insolation because the infrared or heat radiation passes through the cells without being appreciably absorbed to heat the cell

Method for fabricating solar cells having integrated collector grids

A heterojunction or Schottky barrier photovoltaic device comprising a conductive base metal layer compatible with and coating predominately the exposed surface of the p-type substrate of the device such that a back surface field region is formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device having a metal alloy grid network of the same metal elements of the oxide constituents of the mixed metal oxide layer embedded in the mixed metal oxide layer, an insulating layer which prevents electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer, and a metal contact means covering the insulating layer and in intimate contact with the metal grid network embedded in the transparent, conductive oxide layer for conducting electrons generated by the photovoltaic process from the device

Solar cell collector and method for producing same

A transparent, conductive collector layer containing conductive metal channels is formed as a layer on a photovoltaic substrate by coating a photovoltaic substract with a conductive mixed metal layer. A heat sink having portions protruding from one of its surfaces is attached. These protruding portions define a continuous pattern in combination with recessed regions among them such that they are in contact with the conductive layer of the photovoltaic substrate. Heating the substrate while simultaneously oxidizing the portions of the conductive layer exposed to a gaseous oxidizing substance forced into the recessed regions of the heat sink, creates a transparent metal oxide layer on the substrate. A continous pattern of highly conductive metal channels is contained in the metal oxide layer

But What do I Wear? A Study of Women's Climbing Attire

Mrs Henry Warwick-Coleman advises the lady climber on her attire in her 1859 publication, A Lady’s Tour Round Monte Rosa. She suggests ‘A lady’s dress is inconvenient for mountaineering’, continuing ‘even under the most careful management, and therefore every device which may render it less so should be adopted’’ Throughout history clothing can be seen to have been responsible for the development of many theory’s and concepts that have become embedded within the social structure of communities. They form a framework around which society has and still does establish rules, codes and beliefs, embedding a deep sense of social conformity through ‘uniforms’ that express moods and personalities. Emancipation opened up the opportunity for women, to take an active role in the sport of climbing, yet conflicts arose, when it came to the attire they were expected to wear. For women breaking dress codes would cause a scandal, whilst becoming the first to ascend a peak; had its prizes. This paper investigates historical documentation related to the development of women’s climbing and climbing clothing from 1806 to the twentieth century. This will provide an outline of the clothing developmental stages that have taken place and the struggle for inclusion and recognition that women have faced on the mountain

The impacts of electronic word of mouth in social media on consumers` purchase intentions

The influence of Electronic Word of Mouth (eWOM) on consumers` purchase intentions has been known for a long time. However, eWOM has gained a new dimension with the advent of social media. Before this new phenomenon, people were able to talk with anonymous people on the Internet. Social media enable people to talk with friends and acquaintances, on the Internet. This new way of eWOM might be more powerful in terms of triggering purchase intention. This study discusses the electronic word of mouth within the context of social media. Particularly, this study examines the influence of eWOM in social media on consumers` purchase intentions. The research consists of two phases. First, survey will be conducted to understand the effect of eWOM in social media on purchase intention. Then interviews will be made to reveal that how eWOM in social media affects consumers` purchase intentions. The results should contribute to both researchers and practitioners

Agency, identity and learning at turning points in women's lives: A comparative UK-Italian analysis

This paper discusses the ways in which women aged 50, in two different cultural contexts (United Kingdom and Italy) narrate and portray turning points in their life course. Particular emphasis is put on the relationships between identity, learning and agency that emerge through work, family and life experiences. The reference paradigm is adopted from Narrative Learning Theory and the approach is qualitative and comparative in analysing the participant\u2019s voice. For the UK sample, the data sources are 16 semi-structured interviews, including drawings representing the life course, selected from the study deposited in the UK Archives Data under the \u201cSocial Participation and Identity\u201d project; for the Italian sample, the data sources are 28 semistructured interviews and drawings, based on the same selected items of the UK interviews and provided by women living in the North-East of Italy. This study will show how women\u2019s representations of their life course and of turning points in their lives reveal different propensities to reflect on and learn from their own lives. The comparative perspective highlights, through two-level analysis (micro and macro) and by contrasting cultural, relational and social contexts, variations in ways these women are enabled or restricted in moving their lives forward. The research also contributes to methodological insight into the use of drawings in elucidating life course narratives

Fiber distributed feedback laser

Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs