<p>This paper examines whether the phenomena of price drift around quarterly earnings re-leases exist among firms listed on the large cap. list at the Stockholm Stock Exchange for a time period ranging from the first quarter of 2003 to the second quarter of 2006. It fur-thermore examines the ability of the variables forecast error, relative to analyst’s estimates, and firms’ size to explain the variation in price drift among firms.</p><p>A sample of some 30 firms were drawn in the first three quarters of each year between 2003 and 2005, for the year of 2006 only the fist two quarters were included in the study. For each quarter all firms were classified into three different portfolios on the basis of earnings deviations relative to mean analyst’s estimates (forecast error). The returns for each firm in all portfolios were investigated during 20 days post- and pre quarterly earnings release date, resulting in an event window totaling 41 days. In order to clear out effects from general market movements the Capital Asset Pricing Model, CAPM, was used in which betas were estimated for all firms each quarter.</p><p>The findings from this study indicate that price drift, measured by cumulative abnormal re-turn, occur for firms with both negative forecast error as well as positive. For firms with positive error, statistically significant positive price drift was found for both the pre- and post period. As for the firms with earnings below analyst’s mean estimates, negative prean-nouncement drift was statistically supported.</p><p>The ability of firms size and forecast error to explain the variation in price drift on a stock level was very weak, R2 measures of below 5% was reported. However, forecast error was a strongly significant independent variable in the context of the regressions run for both pre- and post-announcement drift. The firms below the lower market cap. quartile in the sample show, on average, lower pre-announcement drift than the firms belonging in the largest quartile.</p><p>Concerning market efficiency among the large cap. firms the price drift found is an indica-tion of market inefficiency both it terms of the semi strong and the strong form. However, care should be taken before generalizing the results from this study but. Possible misspeci-fication of the equilibrium return model will skew the price drift measurement. Moreover, speculation is not explicitly controlled for in this test. Finally, this study is done within a li-mited time span; hence generalization over time is not possible</p>

<p>There are several authors Markowitz (1991), Elton and Gruber (1997) that discuss the main issues that an investor faces when investing, for example how to allocate resources among the variety of different securities. These issues have led to the discussion of portfolio theories, especially the Modern Portfolio Theory (MPT), which is developed by Nobel Prize awarded economist Harry Markowitz. This theory is the philosophical opposite of tradi-tional asset picking.</p><p>The purpose of this thesis is to investigate if an investor can apply MPT in order to achieve a higher return than investing in an index portfolio. Combining a strong portfolio that beats the market in the longrun would be the ultimate goal for most investors.</p><p>The theories that are used to analyze the problem and the empirical findings provide the essential concepts such as standard deviation, risk and return of the portfolio. Further, diversification, correlation and covariance are used to achieve the optimal risky portfolio. There will be a walk-through of the MPT, with the efficient frontier as the graphical guide to express the optimal risky portfolio.</p><p>The methodology constitutes as the frame for the thesis. The quantitative method is used since the data input is gathered from historical data. This thesis is based on existing theories, and the deductive approach aims to use these theories in order to accomplish a valid and accurate analysis. The benchmark that is used to compare the results from the portfolio is the Stockholm stock exchange OMX 30. This index mimics and reflects the market as a whole. The portfolio will be reweighed at a preplanned schedule, each quarter to constantly obtain an optimal risky portfolio.</p><p>The finding from this study indicates that the actively managed portfolio outperforms the passive benchmark during the selected timeframe. The outcome someway differs when evaluating the risk adjusted result and becomes less significant. The risk adjusted result does not provide any strong evidence for a greater return than index. Finally, with this finding, the authors can conclude by stating that an actively managed optimal risky portfolio with guidance of the MPT can surpass the OMX 30 within the selected timeframe.</p>

<p>This thesis presents a solution enabling lower losses in hydraulic actuator systems. A mobile fluid power system often contains several different actuators supplied with a single load sensing pump. One of the main advantages is the need of only one system pump. This makes the fluid power system compact and cost-effective.</p><p>A hydraulic load often consists of two ports, e.g. motors and cylinders. Such loads have traditionally been controlled by a valve that controls these ports by one single control signal, namely the position of the spool in a control valve. In this kind of valve, the inlet (meter-in) and outlet (meter-out) orifices are mechanically connected. The mechanical connection makes the system robust and easy to control, at the same time as the system lacks flexibility. Some of the main drawbacks are</p><p><strong> </strong></p><p><strong>The fixed relation </strong>between the inlet and outlet orifices in most applications produce too much throttling at the outlet orifice under most operating conditions. This makes the system inefficient.</p><p><strong> </strong></p><p><strong>The flow directions </strong>are fixed for a given spool position; therefore, no energy recuperation and/or regeneration ability is available.</p><p>In this thesis a novel system idea enabling, for example, recuperation and regeneration is presented. Recuperation is when flow is taken from a tank, pressurized by external loads, and then fed back into the pump line. Regeneration is when either cylinder chambers (or motor ports) are connected to the pump line. Only one system pump is needed. Pressure compensated (load independent), bidirectional, poppet valves are proposed and utilized.</p><p>The novel system presented in this thesis needs only a position sensor on each compensator spool. This simple sensor is also suitable for identification of mode switches, e.g. between normal, differential and regenerative modes. Patent pending.</p><p>The balance of where to put the functionality (hardware and/or software) makes it possible to manoeuvre the system with maintained speed control in the case of sensor failure. The main reason is that the novel system does not need pressure transducers for flow determination. Some features of the novel system:</p><p><strong>Mode switches </strong>The mode switches are accomplished without knowledge about the pressures in the system</p><p><strong>Throttle losses </strong>With the new system approach, choice of control and measure signals, the throttle losses at the control valves are reduced</p><p><strong>Smooth mode switches </strong>The system will switch to regenerative mode automatically in a smooth manner when possible</p><p><strong>Use energy stored in the loads </strong>The load, e.g. a cylinder, is able to be used as a motor when possible, enabling the system to recuperate overrun loads</p><p>The system and its components are described together with the control algorithms that enable energy efficient operation. Measurements from a real application are also presented in the thesis.</p>

<p>Background: A well-known study, similar to ours, was made in 1985 in America, showing that "loser" portfolios outperformed the market while "winner" portfolios earned less return than the market. This finding is not in accordance with the theory of efficient markets. If a market is efficient, there should be no possibility of making sustainable excess returns and prices should follow a random walk. </p><p>Purpose: The purpose of this thesis is to study a "winner" portfolio and a "loser" portfolio in order to establish whether the Swedish stock market is efficient in the weak form. We will study the efficiency of the A-list at Stockholm Stock Exchange. </p><p>Delimitations: We test efficiency of the Swedish stock market in the weak form. Our investigation comprises stocks registered on the A-list of the Stockholm Stock Exchange. We do not take tax- and transactions costs into consideration in this study. </p><p>Methodology: "Winner" and "loser" portfolios are formed for the period 1997- 2002. We keep the portfolios during a test period of one year, i.e. form new portfolios at the end of each year. The first winner and loser portfolios are selected on the last day of trading in 1996 and the last two portfolios are selected on the last day of trading in 2001. </p><p>Results: Our result indicates that the Swedish stock market is efficient in the weak form during the period 1997-2002.</p>

During the last decade, investments into the Swedish mutual fund market have increased substantially. The increased popularity of actively managed Swedish equity funds among households and investment companies, correspondingly, funds need to deliver substantial results, raised the importance to evaluate these funds’ performance. This thesis adds to the scarce empirical literature on Swedish equity mutual fund performance. Employing the Fama-French three factor model, it analyzes whether actively managed Swedish equity mu- tual funds outperform the Fama-French benchmarks net- and gross of management fees. The study uses time-series data and constructs equally-weighted portfolios of the 42 Swe- dish based actively managed equity mutual funds investing in Sweden for the period 2003- 2013. The portfolios’ excess returns are calculated by estimating the Fama-French three factor model by means of ordinary least squares (OLS) regression analysis. The empirical results show that actively managed equity mutual funds over performed the Fama-French three factor benchmarks by an average annualized net- and gross excess return of 3.60 and 4.67 percent respectively. Sorting out the funds by the performance into deciles, the find- ings indicate that management fees influence the performance of the equity mutual funds in the sample of our study. The conclusion is made such that there is an indication that Swedish equity funds’ managers are able to add value above passive investing.

The study of economics is based on key concepts such as incentives, efficiency, marginality and tradeoffs. Economic research has hypothesized and tested for how economic agents behave after taking each of these into account. In order for agents to meet their objectives it is sometimes the case that they intentionally keep their behaviors out of sight. However, economic theory can be used to search for patterns of observed behaviors from which the unobserved behaviors can be inferred. This dissertation performs this kind of analysis by observing the behavior of sports participants. Chapter 1 is an application of Becker's (1968) economic model of crime by using an econometric model to search for the presence of National Basketball Association (NBA) referees who bet on NBA games. The placement of these bets is not observed since a referee who bets on a game does so illegally and therefore hides his betting activity to prevent detection. A referee who places a bet on a game he also officiates has an incentive to manipulate to improve his chances of winning the bet. At the same time he should also be mindful to manipulate in a way that lowers his chances of being detected. The referee's observed behaviors through detailed play-by-play data are used to look for patterns hypothesized to be consistent with manipulation. The results suggest that former NBA referee Tim Donaghy, who was found to have bet on NBA games, did behave in ways consistent with manipulation. One other referee also appears to engage in the same type of behavior but stops once Donaghy is detected. Chapter 2 is an application of Fama's (1970) Efficient Market Hypothesis (EMH). Typically, the EMH is tested in the financial markets but some research tests for it in the sports betting markets so that the question becomes whether or not the betting market odds fully reflect all of the available relevant information. This chapter tests to see how completely National Football League (NFL) bettors use information called the circadian advantage. This occurs when a game is played in the evening, Eastern Time, between teams that are based on opposite coasts and always favors the better rested West Coast team. A regression model designed to test for market efficiency finds that the advantage is not fully reflected in the odds so that bets on the West Coast team are underpriced. In a majority of games that involve a circadian advantage most of the money is wagered on the overpriced East Coast team. A conclusion that ties these results together is that the bookmakers restrict the amount bet from informed bettors who tend to win their bets and who are aware of the circadian advantage, and adjust the odds just enough to bait uninformed bettors who are unaware of the circadian advantage into placing wagers on the team that is overpriced. Given these dynamics, it is the bookmakers who profit from the information contained in the circadian advantage. Chapter 3 revisits the NFL betting market but instead estimates the extent to which bettors place wagers based on sentiment for a team that is unrelated to relevant measures of relative performance along the lines of speculative investment outlined by Graham and Dodd in 1934 (2009). The results show that more bets tend to be placed on teams for which bettors have high sentiment and fewer bets are placed on teams for which bettors have low sentiment. However, the market odds appear to be using sentiment unbiasedly, leading to the conclusion that contrarian bettors place wagers opposite the sentimental bettors. While the market as a whole is efficient in the use of sentiment, losers tend to be bettors who wager with sentiment and winners tend to be bettors who wager against sentiment.

Electricity generation for Information and Communications Technology (ICT) contributes over 2% of the human-generated CO2 to the atmosphere. Energy costs are rapidly becoming the major operational expense for ICT and may soon dwarf capital expenses as software and hardware continue to drop in price. In this dissertation, three new approaches to achieving energy-proportional operation of network links and data servers are explored. Ethernet is the dominant wireline communications technology for Internet connectivity. IEEE 802.3az Energy Efficient Ethernet (EEE) describes a Low Power Idle (LPI) mechanism for allowing Ethernet links to sleep. A method of coalescing packets to consolidate link idle periods is investigated. It is shown that packet coalescing can result in almost fully energy-proportional behavior of an Ethernet link. Simulation is done at both the queuing and protocol levels for a range of traffic models and system configurations. Analytical modeling is used to gain a deeper general insight into packet coalescing. The architecture of a hybrid web server based on two platforms - a low-power (ARM based) and a high-power (Pentium based) - can be used to achieve step-wise energy-proportional operation and maintain headroom for peak loads. A new method based on Gratuitous ARP for switching between two mirrored platforms is developed, prototyped, and evaluated. Experimental results show that for up to 50 requests per minute, a hybrid server where the Master platform is a 2012 server-grade desktop PC can sleep for 50% of time with no increase in response time. HTTP can be used for redirection in space - a new method for precise redirection in time is proposed and used to schedule requests to a high-power server in a hybrid server. The scheduling method is modeled as a single server queue with vacations where the vacation duration is fixed and the service distribution is directly a function of the request load. This approach is well suited for delay tolerant applications such as application updates and file back-up. Energy-proportional operation is shown to be achievable in a prototype system. A first-order estimation with conservative assumptions on the adoption rate of the methods proposed and studied here shows that these methods can collectively enable energy savings in the order of hundreds of million dollars in the US annually.

The paper examines the application of the concept of economic efficiency to organizational issues of collective information processing in decision making. Information processing is modeled in the framework of the dynamic parallel-processing model of associative computation with an endogenous set-up cost of the processors. The model is extended to include the specific features of collective information processing in the team of decision makers which could cause an error in data analysis. In such a model, the conditions for efficient organization of information processing are defined and the architecture of the efficient structures is considered. We show that specific features of collective decision making procedures require a broader framework for judging organizational efficiency than has traditionally been adopted. In particular, and contrary to the results presented in economic literature, we show that in human data processing (unlike in computer systems), there is no unique architecture for efficient information processing structures, but a number of various efficient forms can be observed. The results indicate that technological progress resulting in faster data processing (ceteris paribus) will lead to more regular information processing structures. However, if the relative cost of the delay in data analysis increases significantly, less regular structures could be efficient. (authors' abstract) / Series: Discussion Papers of the Institute for Economic Geography and GIScience

Energy harvesting is becoming increasingly important in low-power applications where energy from the environment is used to power the system alone, or to supplement a battery. For example, pulse oximeter sensors inside helmets of road racing cyclists are powered by the sun. These sensors have become smaller and more practical without the limitation of a finite energy supply. Harvested energy from an energy transducer (solar, piezoelectric, etc.) must be maximized to ensure these devices can survive periods where environmental energy is scarce. The conversion process from the transducer to usable power for the device is not perfectly efficient. Specifically, the output voltage of a solar cell is a function of the light intensity, and by extension the load it powers. A small perturbation of the light source quickly diminishes the available power. The wasted power reduces the energy available for the application, and can be improved using an approach called maximum power point tracking (MPPT). This technique maximizes harvesting efficiency by dynamically impedance matching the transducer to its load. This report introduces the Maximum Efficient Solar Harvester (MESH), an MPPT algorithm tuned for a specific Wireless Sensor Network (WSN) application. MESH specifically controls the operation of the DC-DC converter in a solar power management unit (PMU). The control is done by monitoring the available light and feeding that information to choose the optimal operating point DC-DC converter. This operating point has a direct dependency on the overall efficiency of the system. For MESH to be practical, the cost and power overhead of adding this functionality must be assessed. Empirical results indicate that MESH improves the maximum efficiency of the popular Texas Instruments (TI) RF2500-SEH WSN platform by an average of 20%, which far exceeds the power overhead it incurs. The cost is also found to be minimal, as WSN platforms already include a large portion of the hardware required to implement MESH. The report was done in collaboration with Shahil Rais. It covers the hardware components and the bench automation environment; Rais's companion report focuses on software implementation and MESH architecture definition. / text

Though adaptational effects are found throughout the visual system, the underlying mechanisms and benefits of this phenomenon are not yet known. In this work, the visual system is modeled as a Deep Belief Network, with a novel “post-training” paradigm (i.e. training the network further on certain stimuli) used to simulate adaptation in vivo. An optional sparse variant of the DBN is used to help bring about meaningful and biologically relevant receptive fields, and to examine the effects of sparsification on adaptation in their own right. While results are inconclusive, there is some evidence of an attractive bias effect in the adapting network, whereby the network’s representations are drawn closer to the adapting stimulus. As a similar attractive bias is documented in human perception as a result of adaptation, there is thus evidence that the statistical properties underlying the adapting DBN also have a role in the adapting visual system, including efficient coding and optimal information transfer given limited resources. These results are irrespective of sparsification. As adaptation has never been tested directly in a neural network, to the author’s knowledge, this work sets a precedent for future experiments. / text