A persistent truck driver shortage and high driver turnover at common carriers limit the effectiveness of some U.S. supply chains. Most driver vacancies result from job hopping, especially among younger drivers. A multiple case study was conducted to explore strategies that some leaders of U.S. common carriers have used to retain millennial-age long-haul truck drivers. Data sources consisted of semistructured, in-person and phone/videoconference interviews; participant observations; and company documents. The sample population was 9 leaders from 6 different common carriers with operations in the southwestern region of the United States who successfully retained millennial long-haul drivers. The conceptual framework was person-organization fit theory. Data were compiled and organized, disassembled into fragments, reassembled into a sequence of groups, and interpreted for meaning. Methodological triangulation and member checking were used to validate the trustworthiness of those interpretations. Five major themes emerged from data analysis: strategic recruiting, competitive compensation, limiting driver time away from home, facilitating driver comfort while away from home, and demonstrating a company culture of driver appreciation. Potentially, carrier leaders can use the lessons learned from this research to reduce driver turnover rates and operating costs and to improve freight reliability for U.S. supply chains. The implications for positive social change include the potential to lower freight costs to shippers and consumers, improve job satisfaction for long-haul drivers, and improve highway safety for truck drivers and motorists.

Long-haul optical fiber communication system is an important technology to support the latest broadband communication in the world, and there is strong competition in optical long-haul transmission to achieve high channel bit rates and large transmission capacity. Therefore, it is important to study a technology to improve the performance of such system. As we have already known, return-to-zero differential phase shift keying (RZ-DPSK) is an attractive solution to improve the long distance transmission system performance compared to the conventional on-off keying (OOK) in a 10-Gb/s system, because it has a high nonlinear tolerance. The dispersion flattened fiber (DFF) is attractive for its ability to improve the system performance. Therefore, it is possible to improve the transmission performance by a combination of the RZ-DPSK and the DFF, and one important technology of the current long-haul optical fiber communication system is the dispersion map. And it is widely deployed for already installed undersea optical fiber communication system in the world. A previous study reported that the blockless type dispersion map showed a superior performance than the block type dispersion map, and some efforts to improve the transmission performance of the block type map were conducted. Fundamental idea to improve the transmission performance of the block type map is to reduce the zero crossing points, and one idea is to shift the map toward the positive or the negative cumulative dispersion to reduce the zero crossing points within the map, but it was not so successful. The other idea is to tilt the dispersion map and it was more successful but not good enough. In this master thesis, I continued the study to improve the long-haul RZ-DPSK system performance using the block type dispersion map. One new idea of the dispersion map shifting, the split shifting, was tried, and another new idea of the dispersion map tilting, the split tilting, was examined. The performance with different repeater output power and different compensation scheme within the dispersion map was simulated by a numerical simulator .The goal is, following previous research, to clarify improved dispersion map design of the long-haul RZ-DPSK based transmission and find the effective method to improve the transmission performance. In addition, I also investigate tolerance of the effective area of the transmission fiber theoretically for the long-haul RZ-DPSK system based on the DFF.

<p> With the increasing demand for data rate and transmission distance, the trend in fiber-optic communications is to build an ultra-high, long-haul transmission system. One of the challenges in this kind of systems comes from the fiber dispersion and dispersion slope. For the wide-band wavelength-division multiplexing (WDM) system or ultra-high bit rate optical time-division multiplexing (OTDM) system, the dispersion slope could be a serious problem to impair the system performance.</p> <p> Many studies have shown that the dispersion and dispersion slope affect the long-haul fiber transmission dramatically, especially for the high-capacity systems. Most of them recommend to totally compensate the dispersion and the dispersion slope simultaneously. And a lot of compensating techniques are proposed. However, it is not easy to realize the simultaneous compensation for the dispersion and dispersion slope in the practical systems. Therefore, the necessity of compensating the dispersion slope in wide-bandwidth systems should be verified.</p> <p> We focus on the study of ultra-high bit rate (160-Gb/s) single-channel fiber-optic transmission. The results show that the dispersion slope is not necessary for the dispersion-managed system when the optimal launch parameters are given. Then we present how to find out the optimum in fiber-optic systems and a novel optimizing technology, space mapping technology (SM) is introduced, which has been successfully applied to the electromagnetic area. An application of SM in optical systems is implemented. By using this smart optimization technique, lots of computational efforts for evaluating the fine model in optimization process are saved.</p> / Thesis / Master of Applied Science (MASc)

As an information intensive industry and as one of the most progressive industries in information technology adoption, travel and tourism provides an ideal context in which to investigate how new technologies such as interactive television challenge our understanding of media and media use. This research looks at how interactive television can be used by consumers and how it may be best applied by marketers in international holiday travel. Using the UK international traveller market to Western Australia as case in point, this research had three main research goals: 1) to understand how travellers use information sources with a focus on interactive television; 2) how an individual’s previous interactive media and travel experiences may pre-dispose them to using interactive television; and 3) to better understand why individuals interact and what impact the interaction has on the promotional effort. A travel ad and a travel show segment were used to explore these with impulse (brochure request) and telescopic (destination video) interactive opportunities. The treatments were deployed over a video-on-demand platform in greater London and participants took part in their homes via their televisions and a self administered questionnaire. This research has furthered the use of the multi-dimensional grid in understanding information sources in relationship to one another and updated the landscape with modern information sources such as television, teletext, the Internet and interactive television. Findings from this area of investigation suggest that current interactive television offerings cater better to short-haul destinations and although it currently plays a minor role, interactive television has the potential to significantly contribute to travellers’ long-haul holiday planning process. The finding that individuals understand interactive television through their experience with teletext rather than the Internet and are more likely to use interactive television if they are thorough and experienced planners supports the theory of knowledge transference. However, most importantly, if an individual has a positive experience with interactive television they will interact again in the future. Contributions were also made to a better understanding of the interactive television user and the use of interactive television applications to the travel and tourism industry in particular. Exploration of the differences between the Impulse and Telescopic approaches to interactivity highlighted that while interactivity generally enhances the promotional effort each approach has its own strategic applications.

Aim The commercial success of some low cost airlines presents the low cost model as very attractive. Until now their main focus has been on short-haul routes, but it is no surprise that they show an interest in entering the long-haul routes market as recent trends are very promising. The aim of this study is to analyze whether the low cost business model is applicable for long-haul routes, which parts of the model are transferable to long-haul services, what competitors responses might be and whether there is potential for low cost airlines operating in Scandinavia to gain frequent, well paying and demanding business travelers on their future long-haul routes. Method In this study a survey method with structured questionnaire distributed by e-mail has been used to collect the primary data. The main source of secondary data has been airline industry literature, newspapers, magazines and data provided by aviation statistical organizations. The empirical part of this study is conducted as a quantitative and qualitative study. Intention of empirical part is to find detailed information and describe business travelers’ behavior, corporate travel policies, business trips pattern and attitude towards low cost airlines. Conclusions The cost savings that low cost airlines achieved in the short-haul market will be much more difficult to achieve to long-haul services. In terms of areas where airlines can achieve cost leadership labor costs is certainly the best area to attack. To be successful, low cost airlines would have to adopt some elements of the traditional business model. But the success of long-haul low cost airlines will not only depend on achieving cost advantages. Availability of leisure time for long-haul trips and response of competitors will be other factors. Suggestions for future research A deeper analysis of low cost long-haul airlines potential could be possible with survey among leisure travelers and VFR (visiting friends and relatives) segment. Contribution of the Study This study has arrived at the conclusion that in order to be successful on long-haul routes low cost airlines would have to keep most of the features of traditional airlines. Low cost long-haul airlines would most probably be successful in pure leisure routes, ethnic markets, during peak season and on dense point to point destinations.

Nowadays, the long-haul optical fiber communication system is one of the important way to convey the information, and there is strong competition of research in the optical long-haul transmission to achieve high channel bit rates and large transmission capacity. Therefore, it is important to study a technology to improve the performance of such system. The return-to-zero differential phase-shift keying (RZ-DPSK) and the return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) have received renewed attention recently for the long-haul transmission systems, because they can improve the transmission performance of the long-haul system. Furthermore, the design of the dispersion map becomes significantly different from that of the conventional system using the intensity modulation direct detection (IM-DD) scheme. Besides, the RZ-DQPSK can transmit two bits per symbol, so it has twice the spectral efficiency of the RZ-DPSK. This study is focusing on the difference of the transmission performance of the long-haul RZ-DQPSK system due to the dispersion map using the numerical simulation.

Amplitude and Phase Shift Keying (APSK) format is one of the most attractive advanced modulation formats because of its good spectral efficiency. As the information bandwidth of the current optical fiber communication system is limited by the optical amplifier bandwidth, it is important to utilize the limited bandwidth effectively. This master thesis focuses on to study the transmission performance of the APSK format both theoretically and experimentally. At first, a theoretical study was conducted using a numerical simulation. As the Extinction Ratio (ER) of the Amplitude Shift Keying (ASK) signal affects the performances of both the ASK and the Phase Shift Keying (PSK) signals, the effect of the ER upon the transmission performance of the APSK format was studied. A clear trade-off between the performance of the ASK signal and the PSK signal due to the change of the ER was observed. Then, in order to improve the performance of the APSK format, a method to improve the transmission performance was proposed. This method was named as ¡§zero-nulling method¡¨, and it solved the trade-off issue caused by the ER. The effectiveness of this method was confirmed through the numerical simulation. Next, an experimental study was conducted. An experimental setup including 330km optical fiber transmission line was prepared, and it was used to confirm the results of the theoretical simulation. The performance trade-off between the ASK and the PSK signals due to the ER was confirmed experimentally. Finally, another experimental study was conducted. An experimental setup of 500km transmission line was used for this study. By adopting the recirculating loop experimental setup, the transmission length could be extended to a few thousand kilometers. The applicability of the ¡§zero-nulling method¡¨ was confirmed using this experimental setup.

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Road freight transportation is important for the development of the global economy and, at the same time, one of the most destructive businesses when it comes to the environment and human health. As societies evolve, the need for freight transportation increases and the transport demand cannot in a sustainable way be fulfilled with the use of diesel trucks as it is done today. For the sake of our environment, the electrification transition needs to ramp up. However, when it comes to covering long distances with an electric truck, problems arise due to the lack of sufficient driving strategies, technology, and infrastructure adapted to the needs for long-distance electrified transportation. Therefore, different battery-electric truck solutions need to be evaluated to identify an economically, socially, and environmentally friendly way of operating. Consequently, the purpose of this master's thesis is the following:  From a carrier operation perspective, identify different solutions for electrified long-haul transportation and evaluate how cost competitive they are based on triple bottom line. To fulfill this purpose the study was divided into two steps, where the first one was to, through literature and interviews, identify different solutions for electric long-haul transportation and external parameters affecting these solutions. The parameters and solutions were then combined with different distances into focus cases. The second step consisted of identifying both internal and external cost drivers, which were used to create a cost model that considered environmental, economic, and social sustainability. The cost model was then used to evaluate the different focus cases to determine their competitiveness. The solutions were based on wire charging, a 300-, 450-, or 624 kWh battery, and were operated either through trailer swap or point-to-point. The external parameters that were the most important ones were battery degradation, the electricity market, and prerequisites for effective logistics. These were all combined into focus cases which were evaluated on the distances 300-, 400-, 500-, and 600 km. The cost model that was used included both internal and external costs to cover the economic, environmental, and social perspectives in the evaluation. To evaluate the focus cases and be able to compare it to a diesel solution the model considered the costs that differ between a battery electric truck and a diesel truck, which at an overall level was electricity cost, charging infrastructure, batteries, salary when charging, environmental, and social costs. For the distance of 300 km, the most competitive combination was wire charging, 300 kWh battery, and trailer swap. For the distances 400- and 500 km the best combination was wire charge, 450 kWh battery, and trailer swap. The best solution for 500 km was wire charge, 624 kWh battery, and trailer swap. The conclusion is, from a carrier operation perspective, that the most competitive solution to use is based on trailer swap, including a battery with a capacity that is adapted to the distance where the batteries can be charged through wire charging at a charger with a high utilization factor. Finally, for shorter distances, a battery electric truck is cost-competitive against a diesel truck. However, at longer distances a battery electric truck's competitiveness in comparison to a diesel truck gets worse, but at all distances the battery electric truck solution is both socially and environmentally beneficial in comparison to a diesel alternative.

<p> Analytical expressions for the propagation impairments due to various noise sources in long-haul optical systems and fiber-to-the-home passive optical networks have been obtained. Extensive comparison has been made in this thesis for systems based on different modulation formats, and the advantage of one over the other is clearly stated.</p> <p> For long-haul fiber optical communication systems with inline amplifiers, we have studied the statistical properties of various noise sources in systems based on differential phase-shift keying (DPSK) such as the linear phase noise induced by the amplifier spontaneous emission (ASE) noise, the intra-channel four-wave mixing (IFWM) and the nonlinear phase noise induced by the interplay between ASE noise and fiber Kerr nonlinearity. The error probability of the system based on DPSK is evaluated semi-analytically. In addition, the error probability of the system based on on-off keying (OOK) is calculated taking into account the effects of ASE noise, and the intra-channel nonlinearities such as IFWM and intra-channel cross-phase modulation (IXPM). Comparison of the performance of systems based on DPSK and OOK is made thereafter.</p> <p> For fiber-to-the-home passive optical networks without inline active photonic devices, different modulation formats have been examined for the downstream and upstream data to enable full-duplex transmission. The statistical properties of Rayleigh backscattering in single-source bi-directional optical systems have been studied including the effects of the high speed external modulation signal and the laser phase noise for systems based on DPSK and OOK. The error probabilities for systems using OOK/OOK topology and DPSK/OOK topology for downstream/upstream transmission have been evaluated and compared.</p> <p> In addition, the interplay of the amplifier spontaneous emission noise, fiber nonlinearity and dispersion has been examined starting from the nonlinear Schrödinger equation on the receiver current fluctuation. The variance of the current noise has been evaluated analytically using the two dimensional perturbation theory.</p> / Thesis / Master of Applied Science (MASc)