Abstract In today¡¦s worldwide economy, to stay competitive a company needs to take advantage of every opportunity to lower their costs, to increase margins and realize the saving that can come from doing business overseas. Today trillions of dollars in the currencies trade everyday in markets around the world. The currency markets are considered to be one of the most efficient markets. As companies dealing with import and export, they have exposure to currencies risk. The increasing difficulty in understanding exchange rate determination has led to for corporations how to approach the currency hedging decision. The importance of financial and operational hedges as tools for managing foreign-currency exposure is examined. In this thesis, the three basic methods for evaluating the currency risks are with the use of the spot rate method, the future rate method and the currency options. The results are summarized as follow: 1. In terms of currency exposure, the sport rate method leaves the currency exposure un-hedged. Futures and the options hedge technique are most widely used and the information to evaluate the use of these instruments as a hedging tool is readily available. Still, the less efficiency method is the future rate method. The most effective approach is the currency options, have the advantage of more flexibility than the future rate. 2. By comparison with the future rate and currency options, the future rate is determinate by swap point, the negative connotations attached to its disadvantage is the ¡§fixed currency rate¡¨. No matter the currency moves toward company¡¦s favor or unflavored, the funds to fulfill the forward contract will be exercised in maturity date. Other than the future rate hedge, the currency options are based upon the ¡§Buy Call¡¨. Within a certain period in the future, when currency rate is moving toward currency¡¦s profit or loss, the company could decide to exercise or give up the ¡§Buy Call¡¨. The difference is that the currency option hedge is determined by the ¡§Right to Exercise Buy Call¡¨ or ¡§Right No to Exercise Buy Call¡¨ which give company more flexibility in FX hedging. In conclusion, the re-thinking of currency hedging is conservative because it is single-mindedly focused on risk-reducing approaches to exchange rate risk management.

Forward osmosis (FO) is one of the emerging membrane technologies in a field of water treatment. The potential advantages of a FO process are lower energy consumption, and higher fouling reversibility compared to other membrane-based desalting technologies, e.g., reverse osmosis and nanofiltration, due to low working pressure. Despite high fouling reversibility, membrane fouling can be still a major obstacle in the FO process. Thus, the employment of spacers can help in enhancing water flux and minimizing membrane fouling. However, the current design of spacers has a potential problem related to spacer fouling, thereby deteriorating the FO process. Therefore, the spacers were examined with the different designs (i.e., hole-type and twisted spacers) fabricated via a 3D-printer for the treatment of shale gas produced water (SGPW). To evaluate the performance of the spacers, either synthetic SGPW or Milli-Q water as feed solution (FS) and different concentration of sodium chloride as a draw solution (DS) were employed. Water flux, reverse solute flux (RSF) and reverse solute flux selectivity (RSFS) were firstly measured with increasing DS concentration with Milli-Q water as FS and a 1-hole spacer exhibited the highest water flux. When increasing FS concentration to 0.3 M NaCl, hole-type spacers exhibited higher water flux than twisted spacers. Therefore, 0-hole and hole-type spacers were selected for SGPW treatment. During SGPW treatment, severe flux decline was observed with all experiments due to the formation of BaSO4 scaling. Flux decline of 1- hole spacers was slightly severer than 0-hole. This might be because scales were broken by high shear force and more covered the membrane surface as shown in SEM images. However, interestingly, hole-type spacers showed no change of pressure drop during SGPW treatment while the pressure drop of the 0-hole spacer increased. Holes of spacers can prevent the accumulation of foulants on the spacer surface, thereby resulting in no change of pressure drop. Physical cleaning with no spacer and the 0-hole spacer showed less than 95% cleaning efficiency while hole-type spacers could enhance the cleaning efficiency and achieve 100%. This might be because the micro-jet induced by holes of the spacer can more readily destroy and remove foulants on the surface.

Keeping a safe distance from the forward-leading vehicle is an essential feature of modern Advanced Driver Assistant Systems (ADAS), especially for transportation companies with a fleet of trucks. We propose in this thesis a Forward Collision Warning (FCW) system, which collects visual information using smartphones attached for instance to the windshield of a vehicle. The basic idea is to detect the forward-leading vehicle and estimate its distance from the vehicle. Given the limited resources of computation and memory of mobile devices, the main challenge of this work is running CNN-based object detectors at real-time without hurting the performance. In this thesis, we analyze the bounding boxes distribution of the vehicles, then propose an efficient and customized deep neural network for forward-leading vehicle detection. We apply a detection-tracking scheme to increase the frame rate of vehicle detection and maintain good performance. Then we propose a simple leading vehicle distance estimation approach for monocular cameras. With the techniques above, we build an FCW system that has low computation and memory requirements that are suitable for mobile devices. Our FCW system has 49% less allocated memory, 7.5% higher frame rate, and 21% less battery consumption speed than popular deep object detectors. A sample video is available at https://youtu.be/-ptvfabBZWA.

In this dissertation we consider cooperative communication systems with relay conferencing, where the relays own the capabilities to talk to their counterparts via either wired or wireless out-of-band links. In particular, we focus on the design of conferencing protocols incorporating the half-duplex relaying operations, and study the corresponding capacity upper and lower bounds for some typical channels and networks models, including the diamond relay channels (one source-destination pairs and two relays), large relay networks (one source-destination pairs and N relays), and interference relay channels (two source-destination pairs and two relays). First, for the diamond relay channels, we consider two different relaying schemes, i.e., simultaneous relaying (for which the two relays transmit and receive in the same time slot) and alternative relaying (for which the two relays exchange their transmit and receive modes alternatively over time), for which we obtain the respective achievable rates by using the decode-and-forward (DF), compress-and-forward (CF), and amplify-and-forward (AF) relaying schemes with DF and AF adopted the conferencing schemes. Moreover, we prove some capacity results under some special conditions. Second, we consider the large relay networks, and propose a "p-portion" conferencing scheme, where each relay can talk to the other "p-portion" of the relays. We obtain the DF and AF achievable rates by using the AF conferencing scheme. It is proved that relay conferencing increases the throughput scaling order of the DF relaying scheme from O(log(log(N ))) for the case without conferencing to O(log(N )); for the AF relaying scheme, it achieves the capacity upper bound under some conditions. Finally, we consider the two-hop interference relay channels, and obtain the AF achievable rates by adopting the AF conferencing scheme and two different decoding schemes at the destination, i.e., single-user decoding and joint decoding. For the derived joint source power allocation and relay combining problem, we develop some efficient iterative algorithms to compute the AF achievable rate regions. Moreover, we compare the achievable degree-of-freedom (DoF) performance of these two decoding schemes, and show that single-user decoding with interference cancellation at the relays is optimal.

Background. In this experiment forward, deferred and tile-based forward rendering techniques are implemented to research about the light-rendering performance of these rendering techniques. Nowadays most games and programs contains a graphical content and this graphical content is done by using different kind of rendering operations. These rendering operations is being developed and optimized by graphic programmers in order to show better performance. Forward rendering is the standard technique that pushes the geometry data through the whole rendering pipeline to build up the final image. Deferred rendering on the other hand is divided into two passes where the first pass rasterizes the geometry data into g-buffers and the second pass, also called lighting pass, uses the data from g-buffers and rasterizes the lightsources to build up the final image. Next rendering technique is tile-based forward rendering, is also divided into two passes. The first pass creates a frustum grid and performs light culling. The second pass rasterizes all the geometry data to the screen as the standard forward rendering technique. Objectives. The objective is to implement three rendering techniques in order to find the optimal technique for light-rendering in different environments. When the implementation process is done, analyze the result from tests to answer the research questions and come to a conclusion. Methods. The problem was answered by using method "Implementation and Experimentation". A render engine with three different rendering techniques was implemented using C++ and OpenGL API. The tests were implemented in the render engine and the duration of each test was five minutes. The data from the tests was used to create diagrams for result evaluation. Results. The results showed that standard forward rendering was stronger than tile based forward rendering and deferred rendering with few lights in the scene.When the light amount became large deferred rendering showed the best light performance results. Tile-based forward rendering wasn’t that strong as expected and the reason can possibly be the implementation method, since different culling procedures were performed on the CPU-side. During the tests of tile-based forward rendering there were 4 tiles used in the frustum grid since this amount showed highest performance compared to other tile-configurations. Conclusions. After all this research a conclusion was formed as following, in environments with limited amount of lightsources the optimal rendering technique was the standard forward rendering. In environments with large amount of lightsources deferred rendering should be used. If tile-based forward rendering is used, then it should be used with 4 tiles in the frustum grid. The hypothesis of this study wasn’t fully confirmed since only the suggestion with limited amount of lights were confirmed, the other parts were disproven. The tile-based forward rendering wasn’t strong enough and the reason for this is possibly that the implementation was on the CPU-side.

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PURPOSE. To evaluate light scatter and stray light in intraocular lenses (IOLs) explanted because of postoperative opacification (13 calcified hydrophilic acrylic, 1 calcified silicone, and 4 polymethylmethacrylate [PMMA] lenses with snowflake degeneration), as well as effect of opacification on other optical quality/performance indicators, in comparison with controls. METHODS. The Complete Angle Scatter Instrument (CASI) scatterometer was used to measure the forward light scattering (FLS) of the IOLs, and the stray light values at various angles were calculated from the measured FLS. Modulation transfer function (MTF) was obtained with an optical bench, and a Badal optometer was used to obtain letter chart images through the lenses. Back light scatter and light transmittance were also measured. RESULTS. Average stray light values (Log (s)) at a scattered angle of 100 were 1.79 +/- 0.37 for hydrophilic acrylic IOLs (controls 0.36 +/- 0.05), 1.53 for the silicone lens (control 0.41), and 1.62 +/- 0.46 for PMMA IOLs (control 0.25). Stray light was significantly higher for explanted opacified lenses (N = 18) in comparison with controls (N = 7; two-tail P < 0.001 at 100). Modulation transfer function and Badal image contrast were drastically reduced in lenses with calcification and snowflake degeneration. CONCLUSIONS. Different studies described the impact of stray light in human vision, with serious hindrance above 1.47 Log (s). Lenses explanted from patients because of clinically significant opacification are associated with a considerable increase in light scatter and stray light, as well as with a decline of other optical quality/performance indicators.

Cardiac disease is one of the leading causes of death in the world, with an increase in cardiac arrhythmias in recent years. In addition, myocardial ischemia, which arises from the lack of blood in the cardiac tissue, can lead to cardiac arrhythmias and even sudden cardiac death. Cardiac arrhythmias, such as atrial fibrillation, are characterised by abnormal wave excitation and repolarization patterns in the myocardial tissue. These abnormal patterns are usually diagnosed through non-invasive electrical measurements on the surface of the body, i.e., the electrocardiogram (ECG). However, the most common lead configuration of the ECG, the 12-lead ECG, has its limitations in providing sufficient information to identify and locate the origin of cardiac arrhythmias. Therefore, there is an increasing need to develop novel methods to diagnose and find the origin of arrhythmic excitation, which will increase the efficacy of the treatment and diagnosis of cardiac arrhythmias. The objective of this research was to develop a family of multi-scale computational models of the human heart and thorax to simulate and investigate the effect of arrhythmic electrical activity in the heart on the electric and magnetic activities on the surface of the body. Based on these simulations, new theoretical algorithms were developed to non-invasively diagnose the origins of cardiac arrhythmias, such as the location of ectopic activities in the atria or ischemic regions within the ventricles, which are challenging to the clinician. These non-invasive diagnose methods were based on the implementation of multi-lead ECG systems, magnetocardiograms (MCGs) and electrocardiographic imaging.

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