Hybrid routing and bridging strategies for large scale mobile ad hoc networks

Multi-hop packet radio networks (or mobile ad-hoc networks) are an ideal technology to establish instant communication infrastructure for military and civilian applications in which both hosts and routers are mobile. In this dissertation, a position-based/link-state hybrid, proactive routing protocol (Position-guided Sliding-window Routing - PSR) that provides for a flat, mobile ad-hoc routing architecture is described, analyzed and evaluated. PSR is based on the superposition of link-state and position-based routing, and it employs a simplified way of localizing routing overhead, without having to resort to complex, multiple-tier routing organization schemes. A set of geographic routing zones is defined for each node, where the purpose of the ith routing zone is to restrict propagation of position updates, advertising position differentials equal to the radius of the (i-i )th routing zone. Thus, the proposed protocol controls position-update overhead generation and propagation by making the overhead generation rate and propagation distance directly proportional to the amount of change in a node\u27s geographic position. An analytical model and framework is provided, in order to study the various design issues and trade-offs of PSR routing mechanism, discuss their impact on the protocol\u27s operation and effectiveness, and identify optimal values for critical design parameters, under different mobility scenarios. In addition an in-depth performance evaluation, via modeling and simulation, was performed in order to demonstrate PSR\u27s operational effectiveness in terms of scalability, mobility support, and efficiency. Furthermore, power and energy metrics, such as path fading and battery capacity considerations, are integrated into the routing decision (cost function) in order to improve PSR\u27s power efficiency and network lifetime. It is demonstrated that the proposed routing protocol is ideal for deployment and implementation especially in large scale mobile ad hoc networks. Wireless local area networks (WLAN) are being deployed widely to support networking needs of both consumer and enterprise applications, and IEEE 802.11 specification is becoming the de facto standard for deploying WLAN. However IEEE 802.11 specifications allow only one hop communication between nodes. A layer-2 bridging solution is proposed in this dissertation, to increase the range of 802.11 base stations using ad hoc networking, and therefore solve the hotspot communication problem, where a large number of mobile users require Internet access through an access point. In the proposed framework nodes are divided into levels based on their distance (hops) from the access point. A layer-2 bridging tree is built based on the level concept, and a node in certain level only forwards packets to nodes in its neighboring level. The specific mechanisms for the forwarding tree establishment as well as for the data propagation are also introduced and discussed. An analytical model is also presented in order to analyze the saturation throughput of the proposed mechanism, while its applicability and effectiveness is evaluated via modeling and simulation. The corresponding numerical results demonstrate and confirm the significant area coverage extension that can be achieved by the solution, when compared with the conventional 802.1 lb scheme. Finally, for implementation purposes, a hierarchical network structure paradigm based on the combination of these two protocols and models is introduced

Multicast outing protocols and architectures in mobile ad-hoc wireless networks

The basic philosophy of personal communication services is to provide user-to-user, location independent communication services. The emerging group communication wireless applications, such as multipoint data dissemination and multiparty conferencing tools have made the design and development of efficient multicast techniques in mobile ad-hoc networking environments a necessity and not just a desire. Multicast protocols in mobile adhoc networks have been an area of active research for the past few years. In this dissertation, protocols and architectures for supporting multicast services are proposed, analyzed and evaluated in mobile ad-hoc wireless networks. In the first chapter, the activities and recent advances are summarized in this work-in-progress area by identifying the main issues and challenges that multicast protocols are facing in mobile ad-hoc networking environments and by surveying several existing multicasting protocols. a classification of the current multicast protocols is presented, the functionality of the individual existing protocols is discussed, and a qualitative comparison of their characteristics is provided according to several distinct features and performance parameters. In the second chapter, a novel mobility-based clustering strategy that facilitates the support of multicast routing and mobility management is presented in mobile ad-hoc networks. In the proposed structure, mobile nodes are organized into nonoverlapping clusters which have adaptive variable-sizes according to their respective mobility. The mobility-based clustering (MBC) approach which is proposed uses combination of both physical and logical partitions of the network (i.e. geographic proximity and functional relation between nodes, such as mobility pattern etc.). In the third chapter, an entropy-based modeling framework for supporting and evaluating the stability is proposed in mobile ad-hoc wireless networks. The basic motivations of the proposed modeling approach stem from the commonality observed in the location uncertainty in mobile ad-hoc wireless networks and the concept of entropy. In the fourth chapter, a Mobility-based Hybrid Multicast Routing (MHMR) protocol suitable for mobile ad-hoc networks is proposed. The MHMR uses the MBC algorithm as the underlying structure. The main features that the proposed protocol introduces are the following: a) mobility based clustering and group based hierarchical structure, in order to effectively support the stability and scalability, b) group based (limited) mesh structure and forwarding tree concepts, in order to support the robustness of the mesh topologies which provides limited redundancy and the efficiency of tree forwarding simultaneously, and c) combination of proactive and reactive concepts which provide the low route acquisition delay of proactive techniques and the low overhead of reactive methods. In the fifth chapter, an architecture for supporting geomulticast services with high message delivery accuracy is presented in mobile ad-hoc wireless networks. Geomulticast is a specialized location-dependent multicasting technique, where messages are multicast to some specific user groups within a specific zone. An analytical framework which is used to evaluate the various geomulticast architectures and protocols is also developed and presented. The last chapter concludes the dissertation

A Faith-Driven Protocol on Gratitude, Forgiveness, and Stress for Chin Refugees from Burma: An Exploratory Study

The influx of immigrants from a diverse cultural and religious tradition into the United States has renewed counselors’ and researchers\u27 interest in how collectivistic populations from a refugee background experience pre-settlement and post-settlement stress in this country. Refugees who have experienced trauma before their settlement are more likely to experience increasing psychiatric pressure from daily stressors such as language barriers, employment difficulties, familial and generational conflicts, and dwindling psychosocial support. However, some refugee populations, such as the Chin people from Burma, have a low-uptake of help-seeking for their psychological problems, leading to more insufficient adjustment to the host culture. Since the Christian faith and the exercise of spiritual disciplines play a critical role in the mental and subjective health of the Chin population, this researcher conducted a workshop to teach a faith-driven approach (also known as GRACE). This exploratory study will describe the development, rationale, and implementation of the protocol. In the outcome analysis using paired sample T-test, participants who practiced the protocol experienced a statistically significant reduction in psychological distress and improved levels of gratitude and motivation to forgive. Also, the researcher reports on the lessons learned from this ethnic minority study, including the limitations of recruitment, randomization, the assessment procedures, and retention of participants

The Effectiveness of Self-regulated Couple Therapy on Intimacy and Marital Adjustment of Couples with Marital Problems

Background and Aim:A marital relationship forms the family, and its continuity and survival depend on the marital relationship's continuation and survival. This study aimed to investigate the effectiveness of Self-regulated couple therapy on intimacy and marital adjustment of couples with marital problems. Materials and Methods:The present study was an applied and quasi-experimental design with pretest-posttest and follow-up with a control group. The statistical population of this study was all couples referred to counseling clinics in 2020. The sample consisted of 30 couples referred to counseling clinics in district 1 of Tehran, selected by convenience sampling method. The data were collected through the marital intimacy scale and marital adjustment questionnaire. Data were analyzed by repeated measure analysis of variance and SPSS.22 software. Results:The results showed that self-regulated couple therapy was effective in increasing intimacy (P<0.001) and marital adjustment (P<0.001) of couples with marital problems. Conclusion:Considering that self-regulated couple therapy promotes husband-wife relationships, as a result, its training improves couple relationships and consequently brings adjustment to couples. The couple's communication program has helped incompatible couples to continue their marital relationships again and increase their problem-solving skills to work on their problems in a constructive way

Design, Analysis, and Performance Evaluation for Handshaking Based MAC Protocols in Underwater Acoustic Networks

Ph.DDOCTOR OF PHILOSOPH

Nagoya Protocol on Access and Benefit Sharing: An Effective International Instrument for Safeguarding the Indigenous Peoples’ Rights or Declarative Rhetoric of Double Standards?

With all real power to regulate the ABS regime in regard to Indigenous Peoples concentrated in the hands of the State’s legislative system, there is no easy solution to the existing unfairness and procedural injustices that were found during the research. Therefore, the international and national laws at issue should be further developed in the direction where they could specify and determine the fair and equitable degree of benefit sharing between the Indigenous Peoples and the businesses involved in the commercialization of the MGRs products and utilization of TK associated with them

A Survey on Various Congestion Control Techniques in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are made up of small battery-powered sensors that can sense and monitor a variety of environmental conditions. These devices are self-contained and fault tolerant. The majority of WSNs are built to perform data collection tasks. These data are gathered and then sent to the sink node. Small packets are sent towards the sink node in such cases, and as a result, the areas near the sink node become congested, becoming the bottleneck of the entire network. In this paper, a survey of existing techniques or methods for detecting and eliminating congestions is conducted. Finally, a comparison in the form of a table based on various matrices is presented