Recent research results on buffer sizing challenged the widely used assumption that routers should buffer millions of packets. These new results suggest that when smooth Transmission Control Protocol (TCP) traffic goes through a single tiny buffer of size O(logW), then close-to-peak throughput can be achieved where W is the maximum window size of TCP flows. But the current routers have the buffer size much larger than that. It is shown that, we can reduce the buffer size by a factor of √N when the traffic is somehow smooth, where N is the number of flows. So, the main goal of this thesis is to show some directions on how the buffer size can be reduced in Internet routers. In this research, we adopted some measures like different packet sizes, different network scenarios, different buffer sizes, various link delays to see the performance of small buffers with the presence of both TCP and UDP traffic. / Graduate

Global warming is caused by Greenhouse Gas (GHG) emissions produced from the use of fossil fuel-based energy sources. Buildings consume about 30%-35% of the global energy use, which makes buildings a major contributor to the global warming problem. A long-term plan has been established at the Thermal Processing Laboratory (TPL) at McMaster University to investigate the use of various renewable energy-based technologies to achieve Net-Zero Energy Buildings (NZEB) in Canada. This paper presents results of an investigation of the effectiveness of using a thermal buffer zone (TBZ) in real buildings. A TBZ is a closed passage built around the building that allows air to passively re-distribute heat energy from solar radiation received on the south side throughout the building. A TBZ offers an effective solution of the overheating problem usually experienced on the south side of the building and, at the same time, it helps in reducing the heating load of the north side of the building. An experimental setup employing TBZ in a model of a typical building floor has been built. An analytical model of the TBZ has been developed. The experimental data has been used to validate the developed analytical model, which then was used to simulate the performance of a TBZ implemented in a real building floor. Results showed that the effectiveness of TBZ could reach 117% in the winter (cold climate countries). Moreover, the study considered the effect of integrating the TBZ with a fan. Results showed that the use of the fan is beneficial for a certain gap width, beyond which the use of the fan is not recommended. In conclusion, results of this study confirm that the TBZ can offer an effective means of replacing parry of building consumption of fossil fuel-based energy using solar energy. / Thesis / Master of Applied Science (MASc)

無 / Critical Chain Project Management (CCPM) has merged in last few years as a novel approach for managing projects. While there were many previous researches studied CCPM concerning with single project management, but CCPM multi project management was hardly paid attention, especially capacity-constraint buffer sizing approach. However, there were some research papers which examined and illustrated CCPM under multi-project environment; those papers assumed all the subprojects were identical. Despite the fact that such situation is impractical. The purpose of this dissertation is to compare Cut and paste method (C&PM) with Root square error method (RSEM) for applying in project buffer, feeding buffer and capacity-constraint buffer sizing and to change some subproject parameters which make an impact on the project schedule for multi-project scheduling. Keywords: Critical chain project management, Multi Project Scheduling, Buffer Management, Capacity constraint buffer, Buffer sizing method.

Call number: LD2668 .T4 1978 H47 / Master of Science

Riparian buffers along stream margins have been widely adopted as a management strategy to mitigate the adverse effects of plantation forestry on stream ecosystems. However, the efficacy of these riparian buffers can be jeopardised by variations in width, length, and vegetation which can range from native and exotic scrub (including bracken, gorse, broom and blackberry) to remnant beech forest. This thesis investigates the influence of riparian vegetation age and composition, on stream ecosystems within exotic pine plantations. Initially, a survey of 50 streams within pine forests of various ages and riparian composition was conducted at sites from mid-Canterbury to Hanmer Springs over the summer of 2004-2005. Additionally, terrestrial subsidies were compared between young pine, mature pine and indigenous forest streams to ascertain differences or similarities between vegetation types. A range of physico-chemical and biological characteristics were recorded, while vegetative age and composition with catchment, riparian buffer and reach scales were determined using GIS. Forestry activities were found to vary temporarily and tended to adversely impact upon streams where riparian buffers were narrow and lacked indigenous vegetation. Stream instability and sedimentation were consistently higher in catchments lacking indigenous riparian vegetation, and more markedly so in recently harvested catchments compared with more mature forests. Streams dominated by pine forests had finer substrates with higher water temperatures and levels of turbidity, while those dominated by indigenous forest had coarser substrates, higher flows and dissolved oxygen levels, and less in-stream debris. Benthic community composition was similar among sites, although taxonomic richness, EPT diversity, and invertebrate abundances were enhanced by indigenous riparian vegetation.

No description available.

Buffer strips alongside watercourses are now a widely accepted method of reducing nutrient and sediment run-off from agricultural land thereby improving water quality and meeting policy goals. However, this change in land use may have consequences for riparian biodiversity which have yet to be fully understood. This study investigated the impact of buffering on various aspects of biodiversity by comparing three types of margins in three river catchments in north east Scotland. Margins were categorised as unbuffered (open and unfenced), buffered (fenced-off vegetated) and wooded (long established woody vegetation - fenced and unfenced). Components of biodiversity studied included vegetation patterns, and the abundance, diversity, movement and assemblage composition of ground-dwelling arthropods focussing primarily, though not exclusively, on ground beetles (Coleoptera, Carabidae). This study further considered management options which may improve or enhance biodiversity. Evidenced changes in vegetation were associated with soil parameters (including decreasing pH), channel morphology, decreasing light availability and tree canopy cover, and bryophyte abundance along a successional gradient from unbuffered-buffered-wooded sites. Buffered and wooded sites showed lower activity density and species richness of ground beetles, but while one measure of functional diversity was high for wooded sites, buffered sites were found to have significantly lower values. Both species and trait assemblage structure of ground beetles were influenced by soil and vegetation, but also by features of buffer strip design such as width, length and age. Active management of sites through grazing or cutting increased ground beetle abundance, particularly hygrophilous species, but did not affect diversity. Radiotracking showed increased movement of ground beetles was correlated with intensity of grazing. Few truly riparian plant or arthropod species were identified indicating the process of buffering essentially 'terrestrialises' the riparian margins. The presence of a tree canopy layer appears to be the key instigator of change in soil conditions with vegetation and arthropods responding accordingly. Therefore planting and maintaining trees in buffer strips could be crucial to ensuring that functional diversity and associated ecosystem services are maintained. Active management through grazing or cutting could help in this regard. The results from this study suggest that rather than buffering all riparian margins within catchments, it is fundamentally important for biodiversity to maintain a mosaic of different successional stages and a diversity of habitats.

<p>In todays GSM network more and more interfaces are run over IP instead of classic synchronized networks. This rises new issues to be solved, for example handling of jitter that use of IP networks introduces. The jitter can be handled by a jitter buffer which ensures that the packets are forwarded in evenly spaced intervals.</p><p>In GSM, data is requested a certain time in advance before delivery to a cellphone. This "time in advance" needs to be adjusted according to the delay of the channel. For an IP network this delay varies (jitter), which means that it would be beneficial to have an algorithm which continuously adjusts how long in advance the packets should be requested. The adjustment is made according to current channel delay and jitter size.</p><p>In this thesis work a model of a general IP network has been developed and isthen used for development of two algorithms for jitter buffer handling. Once the algorithms have been developed they are evaluated and compared to each other and previous solutions to the problem. One of the algorithms is new and the other is an already existing algorithm that has been extended.</p><p>The simplified conclusion is that the behaviors of both algorithms are very similar. They mainly have small packet loss but sometimes the packets are requested earlier than needed and therefore are kept in the buffer a bit longer than necessary. When comparing the two developed algorithms with previous solutions it is visible that they improve the buffer handling a great deal.</p>

Thesis (M.S.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

As the number of processor cores on a chip increases with the advance of CMOS technology, there has been a growing need of more efficient Network-on-Chip (NoC) design since communication delay has become a major bottleneck in large-scale multicore systems. In designing efficient input buffers of NoC routers for better performance and power efficiency, Spin-Torque Transfer Magnetic RAM (STT-MRAM) is regarded as a promising solution due to its nature of high density and near-zero leakage power. Previous work that adopts STT-MRAM in designing NoC router input buffer shows a limitation in minimizing the overhead of power consumption, even though it succeeds to some degree in achieving high network throughput by the use of SRAM to hide the long write latency of STT-MRAM. In this thesis, we propose a novel input buffer design that depends solely on STT-MRAM without the need of SRAM to maximize the benefits of low leakage power and area efficiency inherent in STT-MRAM. In addition, we introduce power-efficient buffer refreshing schemes synergized with age-based switch arbitration that gives higher priority to older flits to remove unnecessary refreshing operations. On an average, we observed throughput improvements of 16% on synthetic workloads and benchmarks.