Approved for public release, distribution is unlimited / This study investigates severe weather events occurring in the Midwest, Central, and Northeastern United States from May through September 2004. Severe weather events are pinpointed using tornado and hail reports and correlating them with NEXRAD radar data to determine maximum intensity of the event. Severe storms that occur within 30 minutes of a model forecast hour are catalogued for further investigation. Once these events are diagnosed, ETA-212 and MM5 model data is regridded, centered on the storm. Divergence values at 300 hPa are extracted from the model data for each storm event. These storms are then grouped in three ways: all storms, tornadic storms, and hail producing storms. The averaged maximum divergence values from the ETA-212 for each group are examined from the 0 hour analysis through the 21 hour forecast. From these averaged divergence values, a matrix of recommended divergence threshold values is derived. For the MM5 data, a subset of storms is examined. The MM5 and ETA-212 are run on an identical set of storms, and the divergence forecasts are compared. / Captain, United States Air Force

Studies have been conducted to highlight the anti-inflammatory and immunosuppressive properties of cannabinoids and also their potentials for cartilage repair and regeneration. Various wound healing techniques can be used to investigate the mechanisms of chondrocyte repair in monolayers or three dimensional tissue constructs. The effect of different concentrations of the synthetic cannabinoids WIN55, 212-2 (WIN-2), URB602 and HU-308 with and without their antagonists on the wound healing of chondrocyte monolayers was investigated using a simple scratch assay model. The three cannabinoids were found to increase wound healing of chondrocyte monolayers, but at different rates. WIN55, 212-2 at a concentration of 1μM had the highest effect of increasing both migration and proliferation of chondrocytes cultured in a chondrogenic media, which increased the rate of wound closure. It was also found that treating the cells with 2μM of any of the cannabinoids lead to a decrease in cell proliferation and the rate of wound closure. These findings were further investigated, by studying the effect of WIN-2 on nitric oxide (NO) and matrix metalloproteinase-2 (MMP-2) expressed by wounded chondrocyte monolayers. Moreover, expression of collagen type-I, collagen type-II, fibronectin and S100 proteins were detected using immunofluorescence and verified quantitatively using ELISA based techniques, following treatment with 1μM and 2μM of WIN-2, for both 2D monolayers and 3D sheets. Treating chondrocytes with 1μM of WIN-2 significantly increased collagen type-II, fibronectin and S100, and significantly reduced collagen type-I compared to control groups in monolayers and chondrocyte cell sheets. On the other hand, both concentrations of WIN-2 significantly reduced the expression of the inflammation markers NO, and MMP-2, in a dose dependent manner. These findings highlight the potential use of the synthetic cannabinoid for improving the rate of wound closure as well as acting as an antiinflammatory agent, which could be used to enhance tissue engineering protocols aimed at cartilage repair.

Approved for public release; distribution in unlimited. / This research develops a detection rate model to analyze the effectiveness of the RDR 1500B search radar installed in the CASA 212 S43 aircraft belonging to Venezuelan Naval Aviation. The model is based on a search and detection mission to find a diesel submarine executing an incursion inside the Venezuelan Caribbean Sea area, assumed to be intermittently operating with periscopes or masts exposed above the sea surface. The analysis obtains cumulative probability of detection vs. time based on the radar manufacturer's performance data, user inputs for aircraft search area size, search speed, and search altitude, and submarine periscope or mast exposure profile. The model can use given periscope radar cross section data, or roughly calculate radar cross section given assumptions about exposed periscope height above the sea-surface and sea-state conditions. Submarine evasion due to radar counterdetection is also modeled. / Lieutenant Commander, Venezuelan Navy

Le besoin de se déplacer est un besoin fondamental dans la vie de tous les jours. Avec l’extension continue des zones urbaines, l’augmentation de la population et l’amélioration du niveau de vie des citoyens, le nombre de voitures ne cesse d’augmenter. Ceci étant, la plupart des transports publics proposés aujourd’hui obéissent à des règles qui manquent de souplesse et qui incluent rarement le caractère dynamique, en temps et en espace, de la demande. Cela réduit ainsi l’attractivité de ces services et les rendant même parfois difficilement supportables. De ce fait, la majorité des usagers utilisent encore leur propre véhicule. Ce grand nombre de véhicules, qui est en augmentation continue sur les réseaux routiers, provoque de nombreux phénomènes de congestion induisant une surconsommation de carburant, des émissions inutiles de gaz à effet de serre et une perte de temps importante. Pour y remédier, nous proposons dans cette thèse de nouveaux systèmes de déplacement des usagers avec différents modèles d’optimisation pour la mobilité partagée (covoiturage et taxis-partagés) ainsi que la combinaison de la mobilité partagée avec les transports publics. Les expérimentations sont réalisées sur de vrais réseaux routiers ainsi que sur des données réelles. Ces nouveaux systèmes améliorent considérablement la qualité de service des systèmes classiques existants en termes de coût et de flexibilité tout en ayant un temps de calcul raisonnable. / The travelling is a fundamental part of everyday life. The continuous expansion of urban areas combined with the population increasing and the improvement of life standards increases the need of mobility and the use of private cars. Furthermore, the majority of public transportations are subject to rules lacking of flexibility and rarely taking into account the dynamic context. The attractiveness of public transportation is therefore reduced and, as a consequence, its financial support, resulting in a further deterioration of the public services quality and flexibility. Therefore, the majority of users still use their own vehicles. The number of vehicles is continuously increasing on road networks causing important phenomena of congestion, high fuel consumption and emissions of greenhouse gases, time loss. This unpleasant situation forces communities to consider alternative solutions for the mobility such as ride-sharing, an interesting alternative to solo car use. The overall objective of this thesis is to propose new travel systems for users through the introduction of optimization models for shared mobility (ride-sharing and taxi-sharing) and the combination of shared mobility and public transportation. The computational experiments are carried out on real road networks and real data. Our numerical results show the effectiveness of our approach, which improves the quality of service compared to the traditional systems in terms of cost and flexibility. The running time remains reasonable to allow using our framework in real-time transportation applications.

Teleoperation of an unmanned vehicle is a challenging task for human operators especially when the vehicle is out of line of sight. Improperly designed and applied display interfaces directly affect the operation performance negatively and even can result in catastrophic failures. If these teleoperation missions are human-critical then it becomes more important to improve the operator performance by decreasing workload, managing stress and improving situational awareness. This research aims to develop electrical and control system of an unmanned ground vehicle (UGV) using an All-Terrain Vehicle (ATV) and validate the development with investigation of the effects of force feedback devices on the teleoperation performance. After development, teleoperation tests are performed to verify that force feedback generated from the dynamic obstacle information of the environment improves teleoperation performance. Results confirm this statement and the developed UGV is verified for future research studies. Development of UGV, algorithms and real system tests are included in this thesis.

Precision control of translational motion is vital for many CNC machine tools as the motion of the machinery affects the dimensional tolerance of the manufactured goods. However, the direct measurement along with the accurate motion control of machine usually requires relatively expensive sensors i.e. potentiometers, linear scales, laser interferometers. Hence, this study attempts to develop reference models utilizing low-cost sensors (i.e. rotary encoders) for accurate position estimation. First, an indirect measurement performance is investigated on a Timing Belt driven carriage by a DC Motor with a backlash included Gearbox head. An advanced interpolated technique is proposed to compensate the position errors while using indirect measurement to reduce the total cost. Then, a similar study was realized with a ball screw driven system. Next, a cable drum driven measurement technique is proposed to the machines which have long travel distance like plasma cutters. A test setup is proposed and manufactured to investigate the capstan drive systems. Finally, characteristics of Optical Mouse Sensors are investigated from different point of views and a test setup is proposed and manufactured to evaluate their performances in long terms. Beside all of these parts, motion control algorithms and motion control integrated circuits are designed and manufactured to realize experimental studies in a detailed manner.

Rapid prototyping (RP) is a set of fabrication technologies that are used to produce accurate parts directly from computer aided drawing (CAD) data. These technologies are unique in a way that they use an additive fabrication approach in which a three dimensional (3D) object is directly produced. In this thesis study, a RP application with a modular architecture is designed and implemented to satisfy the possible requirements of future rapid prototyping studies. After a functional classification, the developed RP software is divided into View, RP and Slice Modules. In the RP module, the process parameter selection and optimal build orientation determination steps are carried out. In the Slice Module, slicing and tool path generation steps are performed. View Module is used to visualize the inputs and outputs of the RP software. To provide 3D visualization support for View Module, a fully independent, open for development, high level 3D modeling environment and graphics library called Graphics Framework is developed. The resulting RP application is benchmarked with the RP software packages in the market according to their memory usage and process time. As a result of this benchmark, it is observed that the developed RP software has presented an equivalent performance with the other commercial RP applications and has proved its success.

In this study, a two axes linear positioning system for testing and applying different rapid prototyping techniques was designed and manufactured. A cable/ pulley mechanism is utilized in the system for transmitting motion from motors into linear motion. Use of a cable/ pulley mechanism overcomes the problems resulting from the utilization of conventional drive systems like ball screws and decreases the overall cost of the system. The carriage elements of both axes were designed and manufactured by using investment casting. The molds used in casting were also designed and manufactured within this study. The designed system is controlled by a servo motion control system composed of a motion controller, DC servo motors and linear encoders. All elements of the motion control system were selected, integrated and programmed within the scope of the study.

In this thesis, development of a control system is aimed for a 1 DOF haptic device, namely Haptic Box. Besides, it is also constructed. Haptic devices are the manipulators that reflect the interaction forces with virtual or remote environments to its users. In order to reflect stiffness, damping and inertial forces on a haptic device position, velocity and acceleration measurements are required. The only motion sensor in the system is an incremental optical encoder attached to the back of the DC motor. The encoder is a good position sensor but velocity and acceleration estimations from discrete position and time data is a challenging work. To estimate velocity and acceleration some methods in the literature are employed on the Haptic Box and it is concluded that Kalman filtering gives the best results. After the velocity and acceleration estimations are acquired haptic control algorithms are tried experimentally. Finally, a virtual environment application is presented.

In this thesis, we study self-organized flocking using a swarm of mobile robots. We first present a mobile robot platform having two novel sensing systems developed specifically for swarm robotic studies. We describe its infrared-based short-range sensing system, capable of measuring the range to obstacles and detecting kin robots. In particular, we describe a novel sensing system called the virtual heading sensor (VHS), which combines a digital compass and a wireless communication module to form a scalable method for sensing the relative headings of neighboring robots. We propose a behavior based on heading alignment and proximal control and show that it is capable of generating self-organized ocking in a group of seven robots. Then, we propose a number of metrics to evaluate the quality of flocking and use them to evaluate four main variants of this behavior. We characterize and model the sensing abilities of the robots and develop a physics-based simulator that is verified against the physical robots for flocking in open environments. After showing in simulation that we can achieve flocking in a group of up to 1000 robots in an open environment, we perform experiments to determine the performance of flocking under different controller parameters and characteristics of VHS using the predefined metrics. In the experiments, we vary the three main characteristics of VHS, namely: (1) The amount and nature of noise in heading measurement, (2) The number of neighboring robots that can be &quot / heard&quot / , and (3) the range of wireless communication. Ourresults show that range of communication is the main factor that determines the scale of flocking, and that the behavior is highly robust against the other two characteristics. We extend an existing particle-based model to determine the phase transition characteristics of flocking under different VHS characteristics. An analytical treatment of the model is also presented and verified against the results obtained from experiments in a physics-based simulator.