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Ever increasing demand for higher data rates and better Quality of Service (QoS) for a growing number of users requires new transceiver algorithms and architectures to better exploit the available spectrum and to efficiently counter the impairments of the radio channel. Multiple-Input Multiple-Output (MIMO) communication systems employ multiple antennas at both transmitter and at the receiver to meet the requirements of next-generation wireless systems. It is a promising technology to provide increased data rates while not involving an equivalent increase in the spectral requirements. However, practical implementation of MIMO detectors poses a significant challenge and has been consistently identified as the major bottleneck for realizing the full potential that multiple antenna systems promise. Furthermore, in order to make judicious use of the available bandwidth, the baseband units have to dynamically adapt to different modes (modulation schemes, code rates etc) of operations. Flexibility and high throughput requirements often place conflicting demands on the Very Large Scale Integration (VLSI) system designer. The major focus of this dissertation is to present efficient VLSI architectures for configurable MIMO detectors that can serve as accelerators to enable the realization of next generation wireless devices feasible. Both, hard output and soft output detector architectures are considered.

At the Tandem accelerator in the Ångström laboratory, Uppsala, Rutherford backscattering spectrometry (RBS) is one of the methods used for thin film analysis, providing information on thickness and composition. The films are commonly grown on silicon substrates, whose crystal structure gives rise to channelling effects (a strong angular dependence in the intensity of the signal), which can cause faulty results. For other samples, channelling may also be used to get information on crystal structure and quality. This work demonstrates new functions to the existing software, aiming at minimizing these effects. The new methods have been tested by measurements both in channelling directions and in directions determined by the old method. In comparison with the earlier method the worst-case error is of order 80 %,commonly around 20 %, but it is possible to achieve an error which is not detectable. It is worth to note that the stated errors appear in tests oriented for maximum channelling, where effects without the new methods give an error corresponding to an apparent thin-film thickness almost 18 times that of the actual thickness. / Vid Tandemlabbet i Ångströmlaboratoriet, Uppsala, används bland annat Rutherford backscattering spectrometry (RBS) för att undersöka egenskaper, t.ex tjocklek och sammansättning, hos tunnfilmer som ofta är odlade på kiselsubstrat. Kiselkristallernas struktur ger upphov till kanaliseringseffekter, d.v.s starkt vinkelberoende intensitet, som i detta sammanhang kan ge felaktiga resultat. För andra prover kan kanaliseringseffekter användas för att få information om kristallstruktur och kvalitet. I det här arbetet demonstreras nyskrivna funktioner till befintlig mjukvara med syfte att minimera dessa effekter. De nya funktionerna har testats genom provtagningar i orienteringar som är gynnsamma och icke gynnsamma för kanalisering. Vid jämförelse med tidigare metoder ger de nya metoderna ett fel på i värsta fall ca. 80%, med bättre parametrar sjunker felet till ca 20 % och med rätt val av parametrar försvinner felet jämfört med tidigare metod. Värt att notera är att ovanstående maximala fel uppstår vid test orienterat för maximal kanalisering, där effekterna utan de nya metoderna ger ett fel på uppemot en faktor 18.

Thesis (Ph.D.)--Michigan State University. Dept. of Physics and Astronomy, 2007. / Title from PDF t.p. (viewed on August 18, 2009) Includes bibliographic references (p. 175-179). Also issued in print.

Different types of business incubators have been established worldwide in the last decade. As the latest generation of incubation models, the accelerator provides a mix of services including mentorship, office space, access to the latest technology and a network of investors, with an aim to help ventures survive in the market. Meanwhile, startups are important to the society because they help balance the labor market and make contributions to the economic growth. The aim of this paper is to find the factors which best predict the success of new ventures based on characteristics of entrepreneurs and ventures. This research utilizes a case study of TechStars Accelerator and includes 640 startups from all industries and geographical regions which participated in the programs between 2007 and 2015. The analysis employs two statistical models, namely the Logit Model and the Ordinary Least Squares (OLS) Model. This study finds that technology intensive ventures founded by a team of entrepreneurs are more likely to succeed. Also, other variables such as the amount of funding, previous industry experience and location have a positive effect on the success of accelerator backed startups.

The use of supplementary cementitious materials (SCMs) in commercial construction have been increasing over the last several decades as climate change and sustainability has been gaining global attention. Incorporation of SCMs into concrete mixtures provides several environmental benefits. Since most SCMs are waste by-products of other industries, their use in concrete reduces waste disposal. Additionally, cements substitution with SCMs reduces the carbon footprint of the construction industry. Cement production generates large amounts of CO2 emissions; the use of SCMs reduces the amount of cement in a concrete mixture thereby reducing emissions from its production. In addition to SCMs, modern concretes typically incorporate a combination of chemical admixtures. Adverse interaction of admixtures with cement, with or without the SCMs, or with each other is one of the most common reasons for early-age concrete issues. Since the possible combinations of admixtures are numerous and there is a variety of cements on the market, testing all possible chemical/mineral/cement admixture combinations is impractical. The aim of this research was to cover a broad base of admixture-related issues, each addressing a specific need of the construction industry. There is currently no explanation for why calcium chloride-based accelerator is not always effective when used with high tricalcium aluminate (C3A) cements. It was determined that increasing C3A or gypsum content alone did not appear to significantly affect acceleration; however, the presence of alkalis reduced the effectiveness of CaCl2 accelerator. When CaCl2-based accelerators are used in concrete, they are typically used in combination with other chemical admixtures, such as water-reducing and retarding admixtures (WRRA) to allow for the use of a low water-cementitious material ratio. In order to avoid premature hardening, CaCl2 accelerator is most often added onsite, rather than at the concrete batching plant. Onsite addition can lead to accidental overdose of accelerator. It was found that increasing dosages of calcium chloride-containing accelerating admixtures in the presence of WRRA has a non-linear effect on the pore size distribution and consequently a non-linear increase on the autogenous shrinkage, which can contribute to early-age concrete cracking. Water-reducing admixtures and superplasticizers are added to concrete to improve workability, which decreases not only with a decrease in water-cementitious material ratio, but also with addition of some SCMs. Silica fume and metakaolin are known to decrease workability; fly ash and slag addition improve it. The effect of SCM combinations on workability is typically assumed to be additive. However, this investigation revealed that combining SCMs does not have an additive effect on workability, measured in terms of apparent yield stress and plastic viscosity; consequently, these parameters cannot be estimated from their respective values. Cement replacement with SCMs affects not only workability, but also heat of hydration, and is commonly used to reduce concrete temperature rise in concrete. Prediction and control of concrete temperature rise due to cement hydration is of great significance for mass concrete structures since large temperature gradients between the surface and the core of the structure can lead to cracking thus reducing durability of the structure. A number of equations have been proposed to predict the heat of hydration of cement and cement/SCM blends. However, these equations do not include metakaolin, which is a relatively new mineral admixture. Based on statistical experimental design, an equation was developed to predict the reduction of total hydration heat at 24, 48 and 72 hours with addition of SCMs compared to a plain ordinary portland cement (OPC)-water mixture. The developed equation allows the evaluation of the contribution of Class F fly ash (FA), blast furnace slag (BFS), silica fume (SF) and metakaolin (MK) as well as their combinations. Since metakaolin has been on the market for only about 10 years, the current knowledge on its effect on hydration products and paste microstructure remains incomplete. The effect of MK on the nature of hydration products was evaluated through x-ray diffraction. Its effect on the microstructure was assessed by measuring porosity with nitrogen adsorption and determining nanoindentation modulus as well as the volume fraction of calcium silicate hydrates (C-S-H) with variable packing densities. No significant effect was observed on the nature of hydration products with MK or BFS addition. However, nitrogen-accessible porosity increased with MK and BFS addition, the increase being larger with BFS. The average indentation modulus for the hydration products decreased with addition of MK and BFS, which corresponded to increasing nitrogen accessible pores. The results of this study indicate that phase quantification by quantitative x-ray diffraction (QXRD) of the hydrated paste may not be sufficient to assess the impact of metakaolin or BFS addition on the hydrating cementitious systems, and a multi-technique approach that provides information not only on the amount of hydration products, but also their morphology is preferable.

Avec le retour des cycles financiers et la crise des subprimes, la littérature a remis en avant l’influence macroéconomique des facteurs financiers. A partir du marché du crédit, elle s’est essentiellement développée avec la théorie de l’accélérateur financier (Bernanke et Gertler [1989], Bernanke, Gertler et Gilchrist [1999]) fondée sur l’hypothèse d’asymétrie d’information. Cette thèse se propose de compléter cette littérature en considérant le cas dans lequel l’offre de crédit s’exprime en situation d’incertitude radicale et de revenir sur cette théorie en proposant, à partir de certaines de ses limites, un autre mécanisme d’accélération financière qui soit de nature plus macroéconomique. Ce mécanisme permet alors d’améliorer la compréhension du rôle du marché du crédit dans l’explication des fluctuations économiques et de réinterpréter les recommandations de politique économique. / With the renewal of financial cycles and the subprime crisis, literature had focused on the macroeconomic influence of the financial factors. From the credit market, it mainly developed along the theory of financial accelerator (Bernanke and Gertler [1989], Bernanke, Gertler and Gilchrist [1999]) which is based on the hypothesis of asymmetric information. This thesis gives aim to complete this literature by considering that credit supply must be also considered in radical uncertainty and to return on it by proposing, from some of its own limits, another mechanism of financial accelerator which can be viewed as more macroeconomic. So, it leads us to improve our understanding of the credit market in the explanation of macroeconomic fluctuations and to reconsider economic policy related.

Purpose The purpose of this thesis is to identify performance outcome criteria for accelerator programs with university links. Hereby, the study aims to extend the knowledge about important evaluation criteria and influencing factors on performance outcome and to close the gap between incubator and accelerator literature. The objective of the study was to investigate, (1) how participating persons evaluate the performance outcome of the accelerator program, (2) how the evaluation between accelerator and incubator differs and (3) why the evaluation differs. Frame of references Literature about science and technology parks, incubators, accelerators and performance evaluation was used to create the theoretical foundation for this thesis. A research gap about the performance outcome evaluation of accelerators was found, due to the newness of the model. Method The study followed an inductive approach and was of exploratory nature. A qualitative case study was chosen to investigate an accelerator within a science and technology park environment. Semi-structured interviews were used to collect the primary data and the methods of coding and categorizing were used to structure and analyse the data. Due to the inductive approach, literature was used to discuss the findings in the end.  Findings Proposition 1: Accelerator performance outcome is mainly evaluated by subjective criteria: “goal realization”, “entrepreneurial motivation” and “entrepreneurial education”. Proposition 2: The performance outcome gets influenced by micro level criteria like “practical experience”, “network support”, “personal development”, “program structure” and “individualization”.

Background: For the past decade, large companies have discovered the high value andpotential to invest in external startups, not only for the financial returns but also moreoften for strategic benefits. Today's corporations boost their innovation in many differentways, and the most successful companies use several different sources of innovation, suchas open innovation, corporate venture capital, incubators and accelerators. One of theinnovation tools, namely Corporate Accelerator (CA) is a relatively new phenomenonthat has gotten much attention lately. An accelerator distinguish itself from otherinnovation tools partly by its deeper focus on business development, which aims atdeveloping startups by providing education within several relevant topics such as finance,marketing, management, mentoring, training program and networks. Accelerators alsodiffer from other innovation models in the way that they are more focused on individualor angel investors as future investors, and less on venture capitalists, and they also oftenbegin with a pre-seed investment in the exchange of equity. Purpose: Due to the limited research made within this field, most studies have relied onmedia and self-collected data, rather than, already developed and existing scientificliterature. The vast increase of use in these territories makes it relevant to explore to gaindeeper insight regarding how CAs can and should be designed. We aim at finding outmore about how different designs of CAs are related to successful investments andthereby provide further directions for corporations, startups, investors and future research.Our focus lies within if a CA is a successful way of investing in startups, and if so, howshould a corporation invest. Method: Empirical data was gathered through semi-structured interviews with differenttypes of accelerators and startups that have participated in accelerator programs. Theauthors have been using grounded theory with an internal realism and positivismapproach. The collected data was analyzed and compared with previous research, but alsothe foundation to answer the research questions. Conclusion: For now, there is limited knowledge about CAs in terms of how they shouldbe designed to reach a certain goal, adopted to the needs of the participants and what aCA really want to accomplish. We can see how previous research tries to distinguishdifferent types of CA by its characteristics, designs, approaches and objectives. Inconclusion, we provide a suggested model of how to invest in startups through corporateaccelerators in consideration of hosting your own or joining a third party CA. Our modelshows when a corporation initiates the decision of being a part of an accelerator, it canchoose to host their own or join a third party. The choice includes several trade-offs.