During the route discovery process, each node receiving the route request packet (RReq) will retransmit it exactly once. A distant neighbor may accidentally receive/loose the only RReq and use it to announce a new route, although that link is inferior/superior for route reply packets (RRep) or actual message routing. Overall, the constructed route may be far from the optimal. All existing route discovery schemes (including DSR/AODV) apply retransmission during route discovery exactly once (1R). Based on a realistic physical layer model, we propose two new route discovery schemes: n-retransmission (nR, retransmitting exactly n times) and n-retransmission c-reception (ncRR), retransmitting until we either reach a total of n own retransmissions or c copies from neighbors are heard. We compare our two new scheme with the traditional one, under otherwise identical conditions (same metric, same packet reception probability on each link) and the same choices about possibly retransmitting again upon discovering a better route (R+) or discarding it (R1), generating route reply packet for every received RRep (B*), or for first and better discovered routes only (B2), and retransmitting RRep exactly once (A1), up to a maximum of three times (A3), or optimally u times decided by link quality (Au). Experimental results show that the proposed ncRR scheme (for n=2 and c=3 or c=4) achieves the best tradeoff between quality of route, success rate and message overhead in the route discovery process, followed by the nR scheme, and both of them are superior to the existing traditional schemes.

Vehicular Ad Hoc Networks (VANETs) are no longer a futuristic promise but rather an attainable technology. Vehicles are already equipped with a variety of computational devices that control or assist drivers in many tasks such as localization, safely breaking, parking and passengers entertainment. The majority of services envisioned for VANETs either require the provision of multimedia support or have it as an extremely beneficial additional feature. In particular, video streaming capabilities over VANETs are crucial to the development of interesting and valuable services. However,VANETs’ highly dynamic topology poses as a demanding challenge to the fulfillment of video streaming’s stringent requirements. The main goal on this thesis is the development of feasible solutions that support the streaming of video content over VANETs. Initially, the main issues of VANETs are explained through both a discussion of its characteristics and the results of some preliminary conclusions. Based on this understanding of VANETs’ peculiarities, three distinguishing solutions are designed REACT-DIS, REDEC and VIRTUS; the two first for video dissemination and the later for video unicast. These solutions offer a great advancement towards the provision of video streaming capabilities but packet loss is still an issue at high data rates. In order to improve the delivery ratios reached by the previous solutions, redundancy is used as an error correction mechanism. The use of redundancy is ideal for VANETs in handling packet loss as they do not require any interaction between source and receivers nodes. Sophisticated coding techniques were used for an efficient use of the increase on entropy of the information sent by the source node. It was also evaluated the selective use of redundancy solely on packets carrying the crucial information of I-frames. Although this selective approach obtained lower overall delivery ratios than when redundancy is used for all packets, the video quality obtained similar improvements under a much lower cost. The evaluation on the use of redundancy has considered the impact on the rate by which unique video content is received at end-users which is fundamental to understand the resolution of videos that can be displayed. This thesis provides several contributions as it advances the knowledge in the peculiarities of VANETs, solutions for video streaming over VANETs and the use of redundancy as an error correction mechanism for video streaming over VANETs.

Tesis para optar al grado de Magíster en Ciencias de la Ingeniería, Mención Eléctrica / Memoria para optar al título de Ingeniero Civil Eléctrico / El desarrollo del transporte en las sociedades del siglo XXI y el aumento explosivo de vehículos presentes en la ciudad, ha traído consigo diversos problemas, tales como: congestión del tráfico en avenidas importantes, empeoramiento de la calidad de aire, el aumento de muertes a causa de accidentes de tráfico, entre otros. Las Tecnologías de Información y Comunicaciones (TICs) ofrecen en este ámbito una oportunidad para poder paliar los problemas asociados al tráfico vehicular dentro de las ciudades. Las llamadas redes vehiculares ad-hoc (Vehicular Ad-hoc Networks VANETs) que se han desarrollado bajo el concepto de las Smart Cities, permiten la confección de un abanico de aplicaciones que explotan mecanismos de comunicación para poder manejar el tráfico, dar mensajes de alertas, implementar esquemas cooperativos, entre otros. Estas redes forman parte de los Sistemas Inteligentes de Transporte (Intelligent Transportation Systems ITS) que en el último tiempo han despertado el interés de distintas instituciones tanto de carácter privado o público, aportando a su desarrollo, investigación e implementación. El desarrollo de este tipo de redes presenta nuevos desafíos, dado que se enfrentan a nuevas dificultades que en las redes digitales convencionales no se experimentan, tales como: topología dinámica, tráfico de red variable, altas velocidades, etc. Surge a partir de estas características, la implementación de un sistema consciente del contexto (Context-Aware System), que permita mejorar el desempeño de mecanismos de diseminación para aplicaciones de seguridad, las cuales requieren de reducidos tiempos de retardo en el traspaso de información. Para lograr este objetivo es necesario que el sistema sea capaz de identificar el escenario de tráfico vehicular y el escenario de tráfico de la red. En este trabajo se propone un sistema consciente del contexto donde para la primera clasificación se utiliza un modelo ya existente ampliamente validado, que luego de algunos ajustes es posible utilizarlo en escenarios urbanos tipo intersección, mientras que para la segunda, se desarrolla un clasificador basado en redes neuronales que permite la discriminación de los escenarios de interés. Ambas fases de clasificación se desarrollan con base en información no directa que maneja cada nodo o vehículo. Los resultados muestran que efectivamente se puede mejorar el desempeño de protocolos de diseminación a través de ajustes de sus parámetros, en concordancia del escenario en el cual se desenvuelven. La estimación de tráfico vehicular resulta ser exitosa utilizando el modelo propuesto, mientras que la clasificación de la carga del tráfico de la red de comunicaciones en escenarios de baja y alta densidad vehicular puede llegar al 99% y 94.5% respectivamente, de muestras clasificadas exitosamente. / CONICYT Chile a través del proyecto RETRACT ELAC2015/T100761

Indiana University-Purdue University Indianapolis (IUPUI) / With the fast development of 5G networks and the advancement in networking technologies, more and more new technologies such as internet of vehicles (IoV) is catching our eyes. With technologies of artificial intelligence and automatic control, IoV is transformed into an intelligent transportation system (ITS). The object of this thesis is to analyze the connectivity probability issues in vehicle ad hoc networks (VANETs), which is a subset of ITS. This will be achieved by a platoon-based two dimensional model. In order to make the results more accurate and more close to real scenario, different situations will be analyzed separately, and different types of platoon will be included. In addition, other system parameters are also discussed and stimulated. The results show that many parameters like the increases of traffic density, ratio of platoon, and lane numbers will improve connectivity probability. No-leader based platoons are easier to connect to the base stations compared to leader based platoons.

AD/HD medications are shown to be significantly more successful at enhancing attention/concentration performance in individuals with AD/HD than placebo treatments. Few studies, however, have investigated the possibility of a placebo reaction in both medication and placebo groups by comparing placebo treatments to no treatment at all. Using an undergraduate population, I evaluated the effect of expectations about a treatment's efficacy on performance in an attention/concentration task. In addition to cognitive performance outcome measures, I included several physiological measures, such as heart rate variability (HRV) through respiratory sinus arrhythmia (RSA). Contrary to expectations, no differences were observed in performance on attention tasks or physiological measurements as a result of the believed efficacy of an orally administered placebo treatment.

The current modern commercial pig is an animal that has evolved through deliberate breeding programs, controlled environmental influences and nutrition to yield a highly efficient feed converter and fertile animal. The objective of this study was to measure the growth performances and carcass characteristics of entire male grower – finisher pigs which were subjected to different seasonal variations, nutrient dense diets, feeding regimes and group situations under South African circumstances. Period 1 was conducted in the winter from 6 June 2008 to 13 August 2008 and Period 2 in the summer from 3 October 2008 to 10 December 2008. The sire lines that were selected for the experiment had the same genetic breeding values (Topigs Selection Index value), of which two sire lines were the same in both Period 1 and Period 2 and one of two different sires lines was used either in Period 1 or Period 2. The animals were fed two different rations, a high (FH) and a low ration (FL), with the low ration’s specifications being 95 % of the high ration. The animals were randomly allocated three different feed regimes throughout the trial; restricted single feeding (RSF), ad libitum single feeding (ASF) and ad libitum group feeding (AGF). In the winter animals had a greater growth response compared to the summer, with end weight and average daily gain being significant (P<0.05) higher. A significant (P<0.05) improvement in average daily gain, feed efficiency and protein deposition rate were observed when animals were fed a higher energy and protein content in their diet, especially during summer. A significant (P<0.05) improved feed conversion was observed for restricted animals, but end weight, average daily gain and average protein deposition rates were significant (P<0.05) lower compared to ad libitum group and individually fed animals. In conclusion; the impact of decreasing the nutrient density of the diet for growing pigs through incremental changes in diet composition had a variable impact on overall growth performance and carcass quality. Feeding the high energy and protein ration improved growth performance during summer, but also in the initial stages of growth when feed intake capacity was limited. The objective when formulating diets should be to provide the essential amino acids and energy in amounts needed to support maximal and efficient growth. Using growth models estimated optimal feed intake curves will not deliver optimal results. Only when measuring and calculating the actual feed intake and protein deposition rates optimal performance levels will be reached. Measurements of feed intake and growth performance data derived from pigs penned individually should be adjusted before they can be applied to commercial situations or research conditions in which pigs are penned in groups. / Dissertation (MSc(Agric))--University of Pretoria, 2010. / Animal and Wildlife Sciences / unrestricted

Le routage dans les réseaux de capteurs, est un service essentiel qui transmet les lectures des capteurs à certains points de collecte de données dans le réseau sur la base des relais multi-saut. Cette tâche est particulièrement difficile car elle doit être réalisé d'une manière efficace au niveau de consommation de ressources et avec une quantité limitée d'informations disponible. La facilité de mise à l'échelle et l'utilisation d'information local pour fonctionner ont permis au routage géographique être considéré comme une approche prometteuse. Cependant, lors de son implémentation, certains problèmes subsistent en raison des difficultés pratiques. Dans ce travail de recherche, deux problématiques inhérentes aux protocoles de routages géographique ont été étudiés: i) Le coût associé: aux évanouissements liés aux obstacles et aux multi-trajets suivis par un signal transmis sur un canal radio, aux changements rapides des conditions physiques du canal de transmission and ii) l'administration de resources affectés à chaque noeud appartenant au réseau. Afin de résoudre ce problème, deux protocoles ont été présentés: un protocole de routage géographique avec communications coopératives, Beaconless Cooperative Geographic cross-layer protocol for ad hoc and sensor networks (CoopGeo) et un protocole de routage basé sur le principe d'extension de couverture: Relay-Aware Cooperative Routing (RACR). / In Wireless Sensor Networks, the routing task is an essential service that forwards the sensor readings to some data collection points in the network on the basis of the multi-hop relaying. The routing task is particularly challenging as it should be realized in an energy efficiency manner with limited amount of information. Geographic routing is a promising approach because of its good scalability and local information use, but when deploying such approach, some problems still remain because of some practical difficulties. In this thesis, some techniques have been explored to address two issues in geographic routing protocols: i) Cost associated to: the wireless channel impairments due to fading, mobility patterns or high dynamic environment and ii) the management of constrained resources of the nodes. To tackle these issues, two protocols were presented: a beaconless Cooperative Geographic cross-layer protocol for ad hoc and sensor networks (CoopGeo) and a Relay-Aware Cooperative Routing protocol (RACR). CoopGeo deals the wireless impairments by means of a cross-layer framework where a beaconless geographic routing approach was used to build the route not only in a local manner, but also on the y worked with a relay selection mechanism to exploit the broadcast nature of the wireless communications. The RACR protocol exploits the coverage extension as a result from node cooperation to improve the non-cooperative geographic routing. It is an alternative to scenarios where network resources like energy should be preserved while respecting a Symbol Error Rate constraint (SER).

An ad hoc network is comprised of wireless mobile nodes without the need of wired network infrastructure. Due to the limited transmission range of nodes, the exchange of data between them may not be possible using direct communication. Partitioning the network into clusters and electing a clusterhead for each cluster to assist with the resource allocation and data packet transmissions among its members and neighboring clusterheads is one of the most common ways of providing support for the existing ad hoc routing protocols. This thesis presents the performance comparison of four ad hoc network clustering protocols: Dynamic Mobile Adaptive Clustering (DMAC), Highest-Degree and Lowest-ID algorithms, and Weighted Clustering Algorithm (WCA). Yet Another Extensible Simulation (YAES) was used as the simulator to carry out the simulations.

Diagnostic and sampling practices documented in studies of participants with Attention-Deficit/Hyperactivity Disorder in Korean journals were investigated. A reliable coding system was used under the supervision of a Korean psychology professor to analyze the diagnostic and sampling documentation practices in articles from high impact Korean journals. Interrater agreement was 88%. Articles in the Korean Journal of Clinical Psychology and the Journal of Korean Neuropsychiatry Association were reviewed and compared with one another and with archival data (Hartley, 2003) from leading American journals. Statistical comparisons were made between Korean psychology and psychiatry journals, Korean and American psychology journals, and Korean and American psychiatry journals. Results showed that important diagnostic practices and criteria are either not being employed or not being documented in Korean journals as well as in American journals. Discussion focuses on recommendations for the international research community.

Devices taking part in mobile ad hoc networks (MANET) co-operate with each other to route packets by strictly adhering to the ad hoc routing protocol in use. Malicious nodes taking part in co-operative routing can launch a wide variety of attacks to reduce the utility of MANETs. The aim of secure routing protocols is to ensure that MANETs can continue to function even in the face of malicious nodes. Secure routing protocols should have measures to dissuade attackers by detecting inconsistencies, identifying the perpetrator responsible for the inconsistency, and provide means to inhibit the role of misbehaving nodes. Most existing secure routing protocols try to achieve only first step, viz., detection of inconsistencies. This dissertation research investigates and proposes efficient strategies that substantially enhance the scope of assurances provided by secure MANET routing protocols while keeping the overhead low.