Dynamic Queue Utilization Based MAC for multi-hop Ad Hoc networks

The end-to-end throughput in single flow multi-hop Ad Hoc networks decays rapidly with path length. Along the path, the success rate of delivering packets towards the destination decreases due to higher contention, interference, limited buffer size and limited shared bandwidth constraints. In such environments the queues fill up faster in nodes closer to the source than in the nodes nearer the destination. In order to reduce buffer overflow and improve throughput for a saturated network, this paper introduces a new MAC protocol named Dynamic Queue Utilization Based Medium Access Control (DQUB-MAC). The protocol aims to prioritise access to the channel for queues with higher utilization and helps in achieving higher throughput by rapidly draining packets towards the destination. The proposed MAC enhances the performance of an end-to-end data flow by up to 30% for a six hop transmission in a chain topology and is demonstrated to remain competitive for other network topologies and for a variety of packet sizes

Queue utilization with hop based enhanced arbitrary inter frame spacing MAC for saturated ad HOC networks

© 2015 IEEE. Path length of a multi hop Ad Hoc networks has an adverse impact on the end-to-end throughput especially during network saturation. The success rate of forwarding packets towards destination is limited due to interference, contention, limited buffer space, and bandwidth. Real time applications streaming data fill the buffer space at a faster rate at the source and its nearby forwarding nodes since the channel is shared. The aim of this paper is to increase the success rate of forwarding the packets to yield a higher end-to-end throughput. In order to reduce loss of packets due to buffer overflow and enhance the performance of the network for a saturated network, a novel MAC protocol named Queue Utilization with Hop Based Enhanced Arbitrary Inter Frame Spacing based (QU-EAIFS) MAC is proposed for alleviating the problems in saturated Ad Hoc networks. The protocol prioritises the nodes based on its queue utilization and hops travelled by the packet and it helps achieving higher end-toend performance by forwarding the packets with higher rate towards the destination during network saturation. The proposed MAC enhances the end-to-end performance by approximately 40% and 34% for a 5hop and 6hop communication respectively in a chain topology as compared to the standard IEEE802.11b. The performance of the new MAC also outperforms the performance of IEEE 802.11e MAC. In order to validate the protocol, it is also tested with short hops and varying packet sizes and more realistic random topologies

Hop-Based dynamic fair scheduler for wireless Ad-Hoc networks

In a typical multihop Ad-Hoc network, interference and contention increase when flows transit each node towards destination, particularly in the presence of cross-traffic. This paper observes the relationship between throughput and path length, self-contention and interference and it investigates the effect of multiple data rates over multiple data flows in the network. Drawing from the limitations of the 802.11 specification, the paper proposes a scheduler named Hop Based Multi Queue (HBMQ), which is designed to prioritise traffic based on the hop count of packets in order to provide fairness across different data flows. The simulation results demonstrate that HBMQ performs better than a Single Drop Tail Queue (SDTQ) scheduler in terms of providing fairness. Finally, the paper concludes with a number of possible directions for further research, focusing on cross-layer implementation to ensure the fairness is also provided at the MAC layer. © 2013 IEEE

Antiferromagnetic ordering of energy levels for spin ladder with four-spin cyclic exchange: Generalization of the Lieb-Mattis theorem

The Lieb-Mattis theorem is generalized to an antiferromagnetic spin-ladder model with four-spin cyclic exchange interaction. We prove that for J>2K, the antiferromagnetic ordering of energy levels takes place separately in two sectors, which remain symmetric and antisymmetric under the reflection with respect to the longitudinal axis of the ladder. We prove also that at the self-dual point J=2K, the Lieb-Mattis rule holds in the sectors with fixed number of rung singlets. In both cases, it agrees with the similar rule for Haldane chain with appropriate spin number.Comment: 4 pages, some references updated and added, typos corrected, to appear in Phys. Rev.

Judaism and the Transpersonal

The interplay between Judaism, especially its mystical tradition, and transpersonal psychology is examined, focusing on two major aspects. The first concerns stages in the spiritual journey, which are analyzed for their psychological import. The stages are symbolically depicted in the biblical narrative of the Exodus from Egypt, a journey from slavery to freedom. Here the Hebrew term translated as wilderness is seen to act as a code word, applying to five successive stages each of which I analyze in psychospiritual terms. The role of the divine feminine, the Shekhinah, is emphasized on account of Her specific role in exile and return. The second area explored is more historical, detailing ways in which Jewish and Kabbalistic ideas have impacted western culture in directions that underpinned the later rise of transpersonal psychology

Enhanced Cross Country Running Course Design: A Study of Historic and Recent Courses, Other Landscape-Based Sports, Athlete Psychology, and Course Elements

Literature suggests that the original and pure elements of cross country course design have faded through time; in order to wholly enhance course design the original elements must be preserved and united with desired modern course elements. Pure sport is defined by an athlete\u27s struggle and persistence that occur amidst tough competition, rugged course elements, and physical pain. In addition to identifying the desired elements through literature review, case studies, and self-experience of cross country course design, it was necessary to confirm the desired elements through interviewing eight key informants. The key informants were renowned and accomplished NCAA cross country coaches selected to represent a wide geographic. These eight informants were interviewed to unveil which elements of cross country courses were desired, important, essential, would advance design, and are underutilized and present in their favored courses. The results from the interviews confirmed a deep desire for enhanced course design by unionizing the elements present in the pure sport of cross country with contemporary desired elements. The new pure sport of cross country can be obtained through the utilization of the elements revealed within this thesis. Designing courses that will provide unchanged emotions from the pure sport of cross country, yet do not incorporate excessively rough course elements, will be the new pure sport of cross country. Overall, the results show designing for the athlete, which includes safety, well defined routing and proper carrying capacity, an accomplished sense of place, advanced technologies and facilities, sport appropriate and safe footing and reasonable terrain, and spectator engagement, would considerably improve design. In order to preserve the pure sport of cross country while also integrating modern desired and necessary elements, course designers must use pioneering design methods in order to incorporate all of the desired elements. The main objective of this research was accomplished and has established a foundation upon which subsequent research efforts may begin. This work serves as a catalyst to improving cross country course design by attaining the knowledge of proper, intensified, and innovative design

The 'I'-tag theory of perception, memory and consciousness.

The distinction between explicit and implicit psychological performance is held to arise as a consequence of differences in self-related processing. In the former, outputs from sensory and memory activity gain ready access to a model of self, referred to here as 'I'. Implicit performance comes about when activity is isolated from 'I' for pathological, or other, reasons. Under normal, explicit circumstances the model of 'I' constructed at a given time is stored in association with representations of concurrent thoughts or percepts. This memory model of' I' is referred to as an 'T'-tag, and is hypothesised to function in subsequent recall. Evidence for the above is drawn from neuropsychological data relating to the implicit/explicit distinction in terms of differential brain systems, and from introspective data concerning the characteristics of conscious processes. Studies of a variety of brain-damaged patients suggest a distinction between decrements in direct stimulus- or motor-related processing and compromised availability of material to consciousness. It is argued here that the latter are consequent on problems in the interpretations of direct processing, specifically those normally involving 'I' as the putative receiver of impressions, controller of memory recollection, and instigator of actions.The Buddhist philosophy of mind analyses the nature of self and details the stages operating in processes of thought and perception. In particular, the notion of'l' implied in the foregoing description is stated to be illusory. The alternative view, that'!' arises as a conditioned association and is without substantive continuity, is supportive of the 'I'-tag concept. The 'I'-tag theory is further developed through an analysis of the stages of perception as detailed in Buddhist thought. Finally, the theory is employed to advance a possible psychological interpretation of a strand of Jewish mysticism in which an artificial anthropoid the golem-was said to be created through linguistic techniques

Re-veiling the Revealed: Insights into the Psychology of “Enlightenment” from the Kabbalah

I explore psychological aspects of a mystically-awakened state as depicted in the Kabbalah. This awakened state is portrayed using imagery of light and is associated with wisdom. The path towards the state entails intense hermeneutic work, and the core characteristic of the awakened person is the ability to see into that which is concealed—be it in scriptural texts, fellow humans, or the outer world. The primary distinction between this kabbalistic state and awakened states as portrayed in recent psychological and perennialist conceptions is the importance of cognitive and intellectual components in the former. I argue that cultural constructions of spiritual goals are impoverished when such intellectual aspects are omitted, and that these aspects can be viewed in meaningful psychological terms