Det kan idag vid förvärv av aktiebolag uppkomma situationer där rekvisiten för både ogiltighet, enligt avtalslagen, och hävning, enligt köplagen, är uppfyllda. Frågan blir då huruvida part har en möjlighet att välja vilket institut denne vill använda sig av för att försöka få rättelse för det fel denne anser är begånget. I stort handlar frågan om kampen mellan generell avtalsrätt och speciell avtalsrätt. Kan en sökande part välja mellan två olika ersättningsanspråk eller är ett val redan förutbestämt? Frågan kan tyckas vara av marginell vikt då de till synes kan ses som två väldigt lika institut. Valet kan dock resultera i enorma skillnader när det kommer till det potentiella ersättningsanspråket. Hävningsinstitutet ersätter vanligtvis det positiva kontraktsintresset medan ogiltighetsinstitutet, via utomobligatoriska ersättningsregler, endast ämnar att ersätta det negativa intresset. Beroende på hur förhandlingarna och det aktuella förvärvet har gått till kan de olika ersättningsanspråken erbjuda fundamentalt olika ersättningar. Det har historiskt sett hävdats att part inte skall få välja mellan anspråken bland annat enbart på grunden att det ena är mer lönsamt än det andra. Författaren kommer dock till slutsatsen att det, i de fall det uppstår en valmöjlighet mellan instituten, alltid föreligger ett så klandervärt beteende från den svarande parten att det inte finns någon anledning för rättsordningen att skydda denne genom att begränsa den sökandes, och förfördelade partens, ersättningsanspråk. / When acquiring a limited company, situations can arise where the prerequisites of both invalidity, under the Swedish Contracts Act, and cancellation, under the Swedish Sale of Goods Act, are met. The question then arises whether the party has an option which regulation they wish to use in order to seek damages for the wrong he believes has been committed. Can an applicant party choose between the two different claims or is it pre-determined? The question may seem to be of marginal importance as they can be seen as two very similar regulations. However, the choice could result in substantial differences in damages. The cancellation regulation generally reward positive contractual liability, while the invalidity regulation, through law of tort, only intends to replace the negative interest. Depending on how the negotiations and the acquisition has proceeded, the different principals of liability can offer fundamentally different compensation. It has historically been argued that parties should not be allowed to choose between claims based solely on the basis that one is more profitable than the other. The author, however, concludes that, in cases where there is a choice between the regulations, it always exists such a fraudulent behavior by the defendant that there is no reason for the legal system to protect them by restricting the aggrieved party’s compensation claim.

Researchers are trying to find a solution for reducing the vibration of the engine with minimum changes to the engine mounts. Several researches and main giant car companies have presented valuable effort in these areas but still new research is needed to improve the control system. The present research carried out a comprehensive study of the state of art methods to suppress unwanted vibration from the engine to the passenger cars. This research was designed based on the objective of the Trelleborg Company to investigate the influence of Active Vibration Control (AVC) on the real engine. Therefore, this thesis tried to challenge the vibration problem with practical engineering approach by implementing different types of controllers experimentally and applying them on the real petrol engine. Inversing controlling technique and PID controller tuned with different methods (Ziegler Nichols and tyreus-luyben) have been tested here on two separate platforms; unbalanced DC motor and petrol engine. In addition, as a requirement of the study, the resonance frequency and related mode shapes of the system was investigated experimentally. It is also shown that using suitable filters can help elimination of high frequency noises in the control signals. This study experimentally tests PID controller with mentioned tuned methods on a real engine with this specific setup for the first time. A new scheme was developed with "mode shapes specific controller system", according to which the shaker position and the controller parameters were specified according to the system mode shapes. The result of applying controllers shows that both control methods have a similar effect on vibration reduction. A 33% - 37% reduction on DC motor achieved in different frequencies (20Hz, 37.5Hz and 46.2Hz) with different control methods, and about 10% reduction on petrol engine at resonance frequency while the shaker IV40 (with max 30N force) was placed on the chassis. For reducing the vibration transmitted from the engine to the chassis, for the first time the shaker was placed on the engine (unlike in previous studies where the shaker was placed on the chassis). Using shaker IV40 placed on the engine results in a 20% reduction in vibration transmission, which is a significant improvement in comparison with having the shaker on the chassis. The optimum result was achieved using shaker IV45 (Max 50N force), which yielded a vibration reduction of 33%.

<p>In this dissertation, I investigated price dynamics in the hotel room-night market and attempted to explain pricing decisions from a market perspective. Since market dynamics of the hotel room-night market can be paralleled to those in the financial market, financial market models allowed for examination of various aspects of hotel room pricing decisions.</p><p>In the first study, advance-purchase discounts were estimated through application of an option pricing model considering property-specific attributes. Non-refundable advance-purchase discounts are a commonly used rate fence. One challenge to their implementation, however, is deciding upon the precise magnitude of the discount. Quan’s (2002) study on the price of room reservations is a good starting point, but it is a conceptual model that assumes away other property-specific factors. This study thus tested the idea that advance-purchase discounts are affected by various components, including the value of the right to cancel a reservation (e.g., cancelation option value) and the room- and property-specific factors in the hotel room-night market (e.g., uncertainty, reviews, and seasonality). The analysis supported this hypothesis and additionally revealed that advance-purchase discounts are smaller for rooms with high review ratings in a high-demand period. Interestingly, the divergence between advance-purchase discounts and cancelation option value components widened in a high-demand period, which implies a tendency by hotels to adjust their room rates rather than the amount of discount for customers who book their stay well in advance. Theoretically, this study thus contributes to finance literature by extending the application of the option pricing model to real options for non-financial assets. This study also contributes to the hospitality literature by demonstrating the effects of property-specific attributes on advance-purchase discount magnitude. The results also have implications to the hospitality industry by providing an analytical framework by which hoteliers can estimate property-specific advance-purchase discounts.</p><p>The second study concentrated on rate parity agreement’s effect on the hotel room-night market’s efficiency at reflecting product characteristics in room rates. This study examined the impact of rate parity agreement between hotels and online travel agencies by comparing hotel rates between Europe and the United States. This study found that room rates were less sensitive to property quality attributes under rate parity clauses. The reflection of property quality on room rates were less efficient when hotels have rate parity agreement with OTAs. Furthermore, the results supported the claim that rate parity exacerbates price increase in periods of high demand, which indicates possible collusion between suppliers (hotels) and distributors (OTAs). The findings provided theoretical implications by testing the market efficiency of the hotel room-night market and confirming the impact at the property level. This study also provided a perspective on pricing decision makers to understand how rate parity agreement influence their pricing decisions. Last, the findings provided support for recent policies in Europe that restrict rate parity agreements between hotels and OTAs.</p><p>The third study empirically examined hoteliers’ response to the demand by observing the price movement of two rates with different cancelation policies—free cancelation rates and non-refundable rates. By modifying Hasbrouck’s (1995) information share approach, this study examined the non-refundable rates’ contribution to the price discovery process. The perceived quality of accommodation by customers, one of the primary determinants of the price discovery process, was included in analysis. The results suggested that non-refundable rates were contribute more to the information variance than free cancelation rates did. The findings also suggested that consumers’ perceived quality and volatility influence non-refundable rates’ contribution to the price discovery process. The results also have practical implications for market participants, as they help to build an understanding of aggregated demand and its impact on pricing. Non-refundable rates are generally regarded as just one of many kinds of discounted rates, but the results of this study suggest that hoteliers should carefully consider the role that non-refundable rates play in their pricing strategy.<br></p>

Land mines are a major humanitarian problem with millions of active mines in place around the world. Since these mines can have little metal in them, novel detection techniques are needed. Nuclear Quadrupole Resonance (NQR) is one such technique. Unfortunately, NQR is highly succeptible to radio frequency interference (RFI). A significant contribution of this thesis is the development of a custom, experimental data acquisition system designed and built specifically for capturing RFI at frequencies significant to NQR land mine detection systems. Another major contribution is the development of data analysis techniques for determining the number of reference antennas required to effectively cancel out RFI at frequencies and in environments typical of an NQR land mine detection system.

Cette thèse est dédié à l’étude de la problématique des interférences multi utilisateurs dans le système Argos et à la proposition des diverses techniques pour réduire les effets de ces interférences. Le système Argos est un système mondial de localisation et de collecte de données géo positionnées par satellite. Il permet à l’échelle mondiale de collecter et de traiter les données émises par des émetteurs installés sur la surface de terre. Ces émetteurs sont connus sous le nom de balises. Ces balises sont installées sur des voiliers, des stations météo, des bouées, ainsi que sur quelques animaux (phoques, penguins, etc.…). Le système Argos a été créé en 1978 par le Centre National des Études spatiales (CNES), l’agence spatiale américaine (NASA) et l’agence américaine d’étude de l’atmosphère et de l’océan (NOAA). Depuis sa création, le nombre de balises Argos n’a cessé d’augmenter afin de couvrir au mieux la couverture mondiale. Nous sommes orientés ainsi à la saturation de la bande d’émission et à la présence des interférences multi utilisateurs (MUI) provenant de la réception simultanée de plusieurs signaux émis par les balises. Cette MUI limite la capacité du système Argos et dégrade les performances en termes de Taux Erreur Bit (TEB). Actuellement, le système Argos n’est capable de traiter qu’un seul signal reçu à un instant donné. D’où, l’intérêt d’implanter des techniques au niveau du récepteur capable de réduire les effets des interférences et de traiter les signaux émis par toutes les balises. Plusieurs techniques de détection multi utilisateurs (MUD) ont été développées dans le cadre de cette problématique. Ces techniques sont principalement implantées dans les systèmes CDMA où des codes d’étalement sont utilisés afin de différencier entre les différents signaux. Ceci n’est pas le cas du système Argos où les signaux ne présentent pas des séquences d’étalement et que les bandes de fréquences pour ces différents signaux ne sont pas disjointes à cause de l’effet Doppler et donc, un recouvrement spectral au niveau du récepteur est très probable. Dans ce contexte, l’objectif du travail présenté dans cette thèse est d’étudier différentes techniques MUD appliquées au système Argos et d’évaluer ces techniques au niveau des performances en termes de TEB et de complexité d’implantation. Dans ce travail, nous présentons les différentes composantes du système Argos ainsi que son mode de fonctionnement. Ensuite, nous présentons la problématique dans le système Argos ainsi que les différentes solutions proposées. Parmi ces solutions, nous montrons celle basant sur l’implantation des techniques MUD au niveau du récepteur. Ces différentes techniques MUD sont alors présentées ainsi que les avantages et les inconvénients de chacune d’elles. Parmi les techniques possédant un bon compromis entre les performances d’une part et la complexité d’autre part, nous notons la technique d’annulation par série d’interférence (SIC). Dans cette technique, les signaux sont démodulés successivement suivant l’ordre décroissant des puissances. Cette technique nécessite une étape d’estimation des paramètres des signaux à chaque étape. L’impact d’une estimation imparfaite des différents paramètres est aussi étudié. Après l’étude des impacts des erreurs d’estimation, nous proposons des estimateurs adaptables au système Argos. Les performances de ces estimateurs sont obtenues en comparant les variances de leurs erreurs aux bornes de Cramer Rao (CRB). Enfin, nous terminons le travail par une conclusion générale des résultats obtenus et nous envisageons les perspectives des prochains travaux. / In our thesis, we investigate the application of multi user detection techniques to a Low Polar Orbit (LPO) satellite used in the Argos system. Argos is a global satellite-based location and data collection system dedicated for studying and protecting the environment. User platforms, each equipped with a Platform Transmitter Terminal (PTT), transmit data messages to a 850 km LPO satellite. An ARGOS satellite receives, decodes, and forwards the signals to ground stations. All PTTs transmit at random times in a 100 kHz bandwidth using different carrier frequencies. The central carrier frequency f0 is 401.65 MHz. Due to the relative motion between the satellite and the platforms, signals transmitted by PTTs are affected by both a different Doppler shift and a different propagation delay. Thus, the Argos satellite receives overlapping signals in both frequency and time domains inducing Multiple Access Interference (MAI). One common approach to mitigate the MAI problem is to implement Multi User Detection (MUD) techniques at the receiver. To tackle this problem, several MUD techniques have been proposed for the reception of synchronous and asynchronous users. In particular, the Successive Interference Cancelation (SIC) detector has been shown to offer a good optimality-complexity trade-off compared to other common approaches such as the Maximum Likelihood (ML) receiver. In an Argos SIC receiver, users are decoded in a successive manner, and the signals of successfully decoded users are subtracted from the waveform before decoding the next user. This procedure involves a parameter estimation step and the impact of erroneous parameter estimates on the performance of Argos SIC receiver has been studied. Argos SIC receiver has been shown to be both robust to imperfect amplitude and phase estimation and sensitive to imperfect time delay estimation. The last part of our work focuses on the implementation of digital estimators for the Argos system. In particular, we propose a time delay estimator, a frequency estimator, a phase estimator and an amplitude estimator. These estimators are derived from the ML principle and they have been already derived for the single user transmission. In our work, we adapt successfully these estimators for the multi user detector case. These estimators use the Non Data Aided (NDA) cases in which no a priori information for the transmitted bits is required. The performance of these different estimators are compared to the Cramer Rao Bound (CRB) values. Finally, we conclude in our work by showing the different results obtained during this dissertation. Also, we give some perspectives for future work on Argos system.