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  • NAT Traversal in Peer-to-Peer Architecture

    Resource Type:
    Report
    Creator:
    Daigle, Alexandre, Poulin, Marc-André, Maldague, Lucas Rioux, and Gagnon, François
    Abstract:
    Peer-to-peer networks are well known for file sharing between multiple computers. They establish virtual tunnels between computers to transfer data, but NATs makes it harder. A NAT, Network Address Translation, is a process which transforms private IP addresses, such as 192.168.2.1, into public addresses, such as 203.0.113.40. The idea is that multiple private addresses can hide behind a single public address and thus virtually enlarge the number of allocable public IP addresses. When an application in the local network establishes a connection to Internet, the packet passes through the NAT which adjusts the IP header and maps an external port to the computer which sent the request. When packets are received from the Internet by the NAT, they are forwarded to the internal host which is mapped to the port on which the packet was received, or dropped if no mapping exists. In this paper, we will introduce you to NAT and P2P, we will discuss the numerous ways NATs use to translate private IP addresses into public ones, we will discuss known techniques used to fix the problem and we will also present how popular peer-to-peer programs bypass NATs. This paper is written so anybody with a reasonable knowledge of networking would grasp the essentials. It is important to keep in mind that the traversal methods presented in this document work for UDP and TCP and require no manual configuration of the Network Address Translator itself.
    Date Created:
    2012-10-30

  • Athermal silicon waveguides with bridged subwavelength gratings for TE and TM polarizations

    Resource Type:
    Article
    Creator:
    Ibrahim, Marc, Janz, Siegfried, Cheben, Pavel, Xu, Dan-Xia, Schmid, Jens H., Ma, Rubin, Aleali, Alireza, Lamontagne, Boris, Bock, Przemek J., Lapointe, Jean, Densmore, Adam, and Ye, Winnie N.
    Abstract:
    In this paper, athermal silicon waveguides using bridged subwavelength grating (BSWG) structures are proposed and investigated. The realization of temperature-independent BSWG waveguides for both polarizations is demonstrated numerically and experimentally. SU-8 polymer is used as the cladding material to compensate for the positive thermo-optic (TO) coefficient (dn/dT) of silicon. We investigate the dependence of the effective TO coefficient of BSWG waveguides on both the bridge width and grating duty cycle. The BSWG waveguides have a width of 490 nm, a height of 260 nm, and a grating pitch of 250 nm. Athermal behavior is achieved for both the transverse-magnetic (TM) and the transverse-electric (TE) polarized light for a variety of bridge width and duty cycle combinations. Furthermore, the BSWGs can be designed to be athermal for both TE and TM polarization simultaneously.
    Date Created:
    2012-07-30

  • Forging A Template for Undergraduate Collaborative Research: A Case Study

    Resource Type:
    Article
    Creator:
    Graham, Debra, Couchman, Ronald, and Hempstead, Janet
    Abstract:
    Undergraduate collaborative research is highlighted in many university initiatives; how-ever there is a lack of exemplars in disciplines that do not employ the scientific method. “Pop Music Reviews” was an attempt to forge a template for Women’s and Gender Stud-ies. This paper presents a description of the pilot project and provides qualitative assess-ments by the first- and second-year students, fourth-year teaching assistant (TA), refer-ence librarian, and professor. Together, the appraisals indicate that there are two different but equally necessary components for a successful collaborative research endeavour: the structural setting and the social and emotional environment. In both these components, there were weaknesses in the areas of planning and background training. Yet, the benefits as perceived through the experiences of the various participants were significant. Report-ed gains included increased understanding of research processes and applications, en-hanced critical thinking skills, expanded disciplinary knowledge, improved student moti-vation and confidence, greater interest in graduate studies, and the fostering of collegial interactions and mentoring.
    Date Created:
    2012-09-09

  • Power up! Building a games collection at an academic library

    Resource Type:
    Poster
    Creator:
    Cross, Emma and Smith, Robert
    Abstract:
    Poster presented at Canadian Library Association Conference 2012. Winner of best poster presentation.
    Date Created:
    2012-06-01

  • Carleton University Library: Library Technician Internship Pilot Project

    Resource Type:
    Poster
    Creator:
    Cross, Emma
    Abstract:
    Overview of a project to establish an internship for library technicians at Carleton University Library. Poster presented at the Ontario Library Association Super Conference January 2012.
    Date Created:
    2012-01-31

  • Understanding the neuroinflammatory response following concussion to develop treatment strategies

    Resource Type:
    Article
    Creator:
    Patterson, Zachary R. and Holahan, Mathew R.
    Abstract:
    Mild traumatic brain injuries (mTBI) have been associated with long-term cognitive deficits relating to trauma-induced neurodegeneration. These long-term deficits include impaired memory and attention, changes in executive function, emotional instability, and sensorimotor deficits. Furthermore, individuals with concussions show a high co-morbidity with a host of psychiatric illnesses (e.g., depression, anxiety, addiction) and dementia. The neurological damage seen in mTBI patients is the result of the impact forces and mechanical injury, followed by a delayed neuroimmune response that can last hours, days, and even months after the injury. As part of the neuroimmune response, a cascade of pro- and anti-inflammatory cytokines are released and can be detected at the site of injury as well as subcortical, and often contralateral, regions. It has been suggested that the delayed neuroinflammatory response to concussions is more damaging then the initial impact itself. However, evidence exists for favorable consequences of cytokine production following traumatic brain injuries as well. In some cases, treatments that reduce the inflammatory response will also hinder the brain's intrinsic repair mechanisms. At present, there is no evidence-based pharmacological treatment for concussions in humans. The ability to treat concussions with drug therapy requires an in-depth understanding of the pathophysiological and neuroinflammatory changes that accompany concussive injuries. The use of neurotrophic factors [e.g., nerve growth factor (NGF)] and anti-inflammatory agents as an adjunct for the management of post-concussion symptomology will be explored in this review.
    Date Created:
    2012-12-12

  • Frontal EEG/ERP correlates of attentional processes, cortisol and motivational states in adolescents from lower and higher socioeconomic status

    Resource Type:
    Article
    Creator:
    Van Roon, Patricia Maria, Oberlander, Tim F., Grunau, Ruth E., Hertzman, Clyde, D’Angiulli, Amedeo, Weinberg, Joanne, and Maggi, Stefania
    Abstract:
    Event-related potentials (ERPs) and other electroencephalographic (EEG) evidence show that frontal brain areas of higher and lower socioeconomic status (SES) children are recruited differently during selective attention tasks. We assessed whether multiple variables related to self-regulation (perceived mental effort) emotional states (e.g., anxiety, stress, etc.) and motivational states (e.g., boredom, engagement, etc.) may co-occur or interact with frontal attentional processing probed in two matched-samples of fourteen lower-SES and higher-SES adolescents. ERP and EEG activation were measured during a task probing selective attention to sequences of tones. Pre- and post-task salivary cortisol and self-reported emotional states were also measured. At similar behavioural performance level, the higher-SES group showed a greater ERP differentiation between attended (relevant) and unattended (irrelevant) tones than the lower-SES group. EEG power analysis revealed a cross-over interaction, specifically, lower-SES adolescents showed significantly higher theta power when ignoring rather than attending to tones, whereas, higher-SES adolescents showed the opposite pattern. Significant theta asymmetry differences were also found at midfrontal electrodes indicating left hypo-activity in lower-SES adolescents. The attended vs. unattended difference in right midfrontal theta increased with individual SES rank, and (independently from SES) with lower cortisol task reactivity and higher boredom. Results suggest lower-SES children used additional compensatory resources to monitor/control response inhibition to distracters, perceiving also more mental effort, as compared to higher-SES counterparts. Nevertheless, stress, boredom and other task-related perceived states were unrelated to SES. Ruling out presumed confounds, this study confirms the midfrontal mechanisms responsible for the SES effects on selective attention reported previously and here reflect genuine cognitive differences.
    Date Created:
    2012-11-19

  • The rights and freedoms gradient of health: evidence from a cross-national study

    Resource Type:
    Article
    Creator:
    Bezo, Brent, Roberts, William L., and Maggi, Stefania
    Abstract:
    This study examined the combined influences of national levels of socioeconomic status (SES), social capital, and rights and freedoms on population level physical and mental health outcomes. Indicators of mental health were suicide rates, alcohol consumption, and tobacco use. Indicators of physical health included life expectancy, infant mortality rates, and prevalence of HIV. Using pathway analysis on international data from a selected sample of European, North American, South American, and South Caucasus countries, similar models for mental health and physical health were developed. In the first model, the positive effects of SES and social capital on physical health were completely mediated via rights and freedoms. In the second model, the positive effect of SES on mental health was completely mediated, while the impact of social capital was partially mediated through rights and freedoms. We named the models, the "rights and freedoms gradient of health" in recognition of this latter construct's crucial role in determining both physical and mental health.
    Date Created:
    2012-11-07

  • Isumaksaqsiurutigijakka : conversations with Aupilaarjuk towards a theory of Inuktitut knowledge renewal

    Resource Type:
    Thesis
    Creator:
    McGrath, Janet Tamalik
    Abstract:
    This dissertation explores a theoretical foundation for Inuktitut knowledge renewal based on conversations between the author, Tamalik, and Inuk elder, philosopher, mentor and teacher Aupilaarjuk from the Kivalliq region in Nunavut. Relational accountability and the relational dynamics of knowledge in Inuktitut contexts are examined, along with Inuktitut methodological principles. The dissertation is presented in two parts to honour two different languages, epistemologies and intellectual systems. Part O n e is in Inuktitut syllables; it comprises the recorded conversations between the author and Aupilaarjuk in May of 2010 and represents the importance of Aupilaarjuk's narrative as a whole, legible or not to the academy. Part T w o is an exercise in bridging between two diverse intellectual traditions that coexist within Canada - Inuktitut indigenous and western academic, and a case is made for their coexistence within the academy. Together the two parts of the document work to support a framework for understanding Inuktitut knowledge traditions and the value of intercultural dialogue in addressing questions of knowledge production in arctic and Inuit-related affairs.
    Thesis Degree:
    Doctor of Philosophy (Ph.D.)
    Thesis Degree Discipline:
    Canadian Studies
    Date Created:
    2012

  • Geology of the Tincup Lake area, southwestern Yukon : implications for the tectonic evolution of the western margin of the Yukon-Tanana terrane

    Resource Type:
    Thesis
    Creator:
    Scott, Steven
    Abstract:
    The lineup lake area (NTS 115G/1114) comprises 12 map units of polyfolded upper greenschist to lower amphibolite facies metasedimentary and metavolcanic rocks correlated with assemblages of Yukon-Tanana terrane. Mapping at a scale of 1: 20,000 was carried out, resulting in the identification of four generations of late Permian (?) to late Cretaceous folding and two generations of late Cretaceous, or younger, faulting in the lineup lake area. Well exposed Cal marble marker units constrain the orientation and geometry of map units in this structurally complex area. In the southern part of the lineup lake area the map pattern is controlled by F2 long limbs that are moderately to steeply S dipping. In the northern part of the lineup Lake area, Sdipping or gently NW-dipping F3 limbs control the map pattern. South-dipping, brittle normal faults crosscut folds and are in turn cut by a network of nearvertical, dextral strike-slip faults striking 305°-335° and with 500- 2000m spacing. The steep faults are inferred to be related to the Denali fault and were coeval with regional strike-slip faults that cut the Late Cretaceous to Early Paleocene Ruby Range Batholith to the south. South-dipping, brittle normal faults crosscut folds and are in turn cut by a network of nearvertical, dextral strike-slip faults striking 305°-335° and with 500- 2000m spacing. The steep faults are inferred to be related to the Denali fault and were coeval with regional strike-slip faults that cut the Late Cretaceous to Early Paleocene Ruby Range Batholith to the south.
    Thesis Degree:
    Master of Science (M.Sc.)
    Thesis Degree Discipline:
    Earth Sciences
    Date Created:
    2012