The purpose of this study is to develop, evaluate, and apply a CRISSP-2D river ice model for a highly complex reach of the Nelson River upstream of the Jenpeg Generating Station in northern Manitoba. The calibrated model is applied in a backcasting scenario to evaluate its potential of predicting the river ice regime associated with specific hydraulic and meteorologic conditions. Secondly, a real-time application is conducted in collaboration with Manitoba Hydro to forecast overnight ice conditions as part of the 2011 Ice Stabilization Program. The model is shown to be fully capable of predicting the onset and type of ice regime that occurs. Spatial variation in ice generation across the study region is accurately captured, including locations of thermal bridging and initial ice front advance. Several modelling limitations associated with parameterization limit model accuracy during the latter stages of freeze-up and are identified as enhancement opportunities.

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In this Thesis, we propose a mechanism to dynamically adjust the video bit rates through the segmentation and the reassembly of SVC (Scalable Video Coding) segments in a P2P network. At the transmitter, an SVC film is segmented into a number of segments with different sizes. Each segment is further chopped into Torrents according to three scalabilities of SVC (Temporal, Quality, and Spatial). The Torrents with three scalabilities are referred to as 3D-Torrents. At the receiver, we present three approaches of grabbing Torrents (Temporal-First, Quality-First and Interleaving) form P2P networks to validate that the proposed 3D-Torrent reassembly can adapt to different bandwidths and to fit different hardware equipments so that any possible video freeze-up time can be avoided. To demonstrate how the proposed 3D-Torrent reassembly affect video bit rates in the P2P video streaming environment, we implement the segmentation, grabbing, and reassembly of Torrents on a Linux platform. In the P2P network built by Hadoop, we study (i) the video freeze-up time with/without adopting 3D-Torrent reassembly, (ii) video quality under different grabbing approaches using two different types of video, static and active background. To compare the video quality at the transmitter to that at the receiver, we modify the conventional PSNR equation. Two new dimensions, Temporal and Spatial, are included in the new PSNR3D equation to compare the video quality between the transmitter and the receiver. From the experimental results, we observe that the freeze-up time approaches zero using the 3D-Torrent reassembly and video bit rates can be dynamically adjusted according to the available bandwidth.

In this paper, we propose two schemes for layer allocations to adjust the number of layers of SVC (Scalable Video Coding) segments according to the bandwidth variation in P2P video streaming networks. The first scheme is Periodical Layer Allocation (PLA) that can adjust the number of layers to fully satisfy the available bandwidth measured periodically. However, when the available bandwidth is changed abruptly, two major drawbacks may be occurred by PLA algorithm; first, the quality of video frames may become unsmooth so that users would feel uncomfortable about the picture quality, and second, the cost is increased due to the periodical measurement of the available bandwidth. Therefore, we propose Dynamic Layer Allocation (DLA), to dynamically change the time interval for adjusting SVC layers. When freeze-up occurred or when there was not enough buffer space to store the video segments during the interval, the interval would be reduced. When the interval for adjusting SVC layers was expired, available bandwidth can be determined by the number of video segments waiting in the buffer. Compared with PLA, DLA adjusts the SVC layers gracefully so that the quality of picture becomes smoother and users feel more comfortable while watching the film. We built a simulator written in C++ under two scenarios: the available bandwidth is changed abruptly and the one changed gradually. Simulation results show that the performance of PLA is quite similar to DLA when the available bandwidth is changed gradually. However, when the available bandwidth is changed abruptly, DLA can not only obtain the smoother video film but also decrease the freeze-up time significantly.

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This study is part of a three year project aimed to assess the effects of industrial water withdrawals on the ice regime of the Athabasca River. A 2-D numerical model was used to provide quantitative data for this effort. Freeze-up monitoring was carried out over two years along 80-km of the river from Fort McMurray to Bitumount. Summer bathymetric and winter ice surveys were conducted along with discharge measurements on a 5-km long detailed study reach that exhibited the full range of ice cover initiation processes. The data collected was used to build a CRISSP2D river ice process model for the simulation of freeze-up processes. An extensive parametric assessment was carried out to evaluate the capabilities of the model. Although it was not possible to simulate bridging, the simulated border ice agreed very well with field observations. Limitations of the model are addressed and future research recommendations are included. / Water Resources Engineering

River-ice break-up in high-latitude regions, despite its brevity, is a fundamental process, representing the most dynamic and complex period of fluvial processes. Moreover, ice break-up has significant cascading ecological effects, with a different severity for mechanical vs. thermal break-up, and thus, motivates the importance of monitoring efforts. Classical research methods, such as fieldwork or analysis of photographs and aerial imagery, offer a general perspective on the timing of ice break-up but have safety and logistic issues caused by the dangers of unstable ice cover, the lag times between event occurrence and observation, and the frequent low visibilities. The emerging field of environmental seismology, which studies surface processes through seismic signals, provides an alternative solution to these shortcomings by continuously recording high temporal resolution data. Seismic sensing can potentially record any event within a set distance if the produced signal is powerful enough. Three geophones had monitored the subarctic Sävar River reach for 185 days to test the efficiency of seismic methods to capture ice-cracking events, and based on their characteristics, to identify thermal vs. mechanical ice break-up. With visual and multivariate analysis, seismic methods provided a conservative set of 2 228 events, detected at milliseconds precision, described, and located. Besides, both trigger lag times and principal component analysis depicted correlations between environmental drivers and ice-cracking events. The automatic picker based on duration and trigger thresholds required manual supervision because of the initial numerous false signals that accounted for 96% of total initial events. Ice-cracking signals as short as 0.2s and frequencies of 8-40 Hz with an average power of -117 dB were statistically defined, classified, and described by case events as two types, associated, based on their spectral and temporal patterns, with the two ice break-up modes. With an estimated Rayleigh wave velocity of 680 m/s, all ice-cracking signals' locations were within the instrumented area. Trigger lag times analysis improved detection and showed a strong link between ice-cracking events and drivers of lag times less than three hours, including near-immediate responses (< 2s). With multivariate analysis, the lag times showed a mainly climatic control for thermal melting and a primarily fluvial control in mechanical ice break-up. The combination of statistical and seismic analysis provides, despite the considerable manual screening, a valid and potentially site-transferable method to extract and describe ice-cracking signals and thus identify ice break-up modes in northern rivers.