Measurements in a turbulent counterflow flame

Imperial Users onl

Using internal states and swarming behaviours to enhance the performance of swarm robots

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Potential field based navigation for planetary rovers using internal states

The work in this paper aims to introduce analysis and applications for the internal state model which is a new model for a swarm of rovers interacting via pair-wise attractive and repulsive potentials. The internal state model updates the state of the art in overcoming the local minima problem through solving the problem with comparatively lower computation cost than other methods. The simulations results show that using the internal state model, a swarm of planetary rovers, rather than moving in a static potential field, are able to manipulate the potential according to their estimation of whether they are moving towards or away from the goal, which allows them to escape from and maneuver around a local minimum in the potential field to reach a goal. An application of a swarm of rovers to solve the problem for different shaped obstacles is introduced to show the efficiency of the model. The model proves stable convergence to a goal and provides similarities with the behaviour of real groups of animals

NOVEL OFDM SYSTEM BASED ON DUAL-TREE COMPLEX WAVELET TRANSFORM

The demand for higher and higher capacity in wireless networks, such as cellular, mobile and local area network etc, is driving the development of new signaling techniques with improved spectral and power efficiencies. At all stages of a transceiver, from the bandwidth efficiency of the modulation schemes through highly nonlinear power amplifier of the transmitters to the channel sharing between different users, the problems relating to power usage and spectrum are aplenty. In the coming future, orthogonal frequency division multiplexing (OFDM) technology promises to be a ready solution to achieving the high data capacity and better spectral efficiency in wireless communication systems by virtue of its well-known and desirable characteristics. Towards these ends, this dissertation investigates a novel OFDM system based on dual-tree complex wavelet transform (D

Swarm potential fields with internal agent states and collective behaviour

Swarm robotics is a new and promising approach to the design and control of multi-agent robotic systems. In this paper we use a model for a system of self-propelled agents interacting via pairwise attractive and repulsive potentials. We develop a new potential field method using dynamic agent internal states, allowing the swarm agents' internal states to manipulate the potential field. This new method successfully solves a reactive path planning problem that cannot be solved using static potential fields due to local minima formation. Simulation results demonstrate the ability of a swarm of agents that use the model to perform reactive problem solving effectively using the collective behaviour of the entire swarm in a way that matches studies based on real animal group behaviour

INTERFACING CMOS CAMERA WITH ARM MICROCONTROLLER FOR SMALL ROBOTIC PLATFORM

This proposal presents an autonomous color tracking mobile robot with obstacle avoidance. The robot detects the object color through CMUcam2. CMUcam2 is a camera which comes with an onboard image processing capabilities and can be interfaced directly to microcontroller. The robot follows the object according to the algorithm that had been programmed. The heart of the system is Raspberry Pi. Raspberry Pi is a credit-card sized computer that is powered by ARM11. This device runs on Linux OS and can be programmed to do specific functions. It supports many environments such C, Python and many more. The interfacing between the CMUcam2 and Raspberry Pi is performed through serial communication. The robot is programmed with Linux as the OS and C language to do the algorithm. In this project, a simple image processing technique is employed to process the image. The robot should be able to detect a specific color and follow it

Atrial electromechanical abnormalities in hypertensive patients with diastolic dysfunction

PurposeIt was to compare atrial electromechanical delays (AEMDs) by pulsed tissue Doppler echocardiography between hypertensive patients and healthy controls. It was used as a predictor for development of atrial arrhythmias as proved by other studies.MethodsWe examined 60 subjects; 20 normotensive (Controls), 20 hypertensive with LV diastolic dysfunction (Group I) and 20 hypertensive without LV diastolic dysfunction (Group II). Exclusion criteria were: receiving B-blockers or non-dihydropyridine calcium channel blockers, Diabetes mellitus, Coronary heart disease and Systolic heart failure. All were examined to assess BP, left atrium and ventricle, and mitral valve flow. The Pulsed wave tissue Doppler imaging is used to assess diastolic function and AEMDs. In apical 4-chamber view, using the pulse wave Doppler, Time intervals from the onset of P wave on surface electrocardiography to the beginning of A wave (PA) were obtained from lateral mitral annulus, septal mitral annulus, and lateral tricuspid annulus and named as lateral PA, septal PA, and RV PA, respectively. The difference between septal PA and RV PA was defined as Intra-right AEMD. The difference between lateral PA and septal PA was defined as Intra-left AEMD .The difference between lateral PA and RV PA was defined as Inter-AEMD.ResultsThe Inter-AEMD was significantly higher in Group I compared with Group II and Controls. The Intra-Left AEMD was significantly higher in Group I and Group II compared with Controls. There was no significant difference between Controls and Groups as regard to Intra-Right AEMD. There was a positive correlation between systolic blood pressure, LA diameter and volume, LV mass, E/E′ from one side and Inter-AEMD and Intra-Left AEMD from the other side. There was a negative correlation between E wave, E/A ratio and E′ wave from one side and Inter-AEMD and Intra-LeftAEMD from the other side. The Inter-AEMD and the Intra-Left AEMD were significantly higher in subjects with LV hypertrophy than those without. There was no significant correlation between the Intra-Right AEMD and left ventricular hypertrophy.ConculsionThe Inter-AEMD was significantly higher in hypertensive patients with diastolic dysfunction compared with those without diastolic dysfunction and controls. Intra-left AEMD was significantly higher in hypertensive patients with diastolic dysfunction and without diastolic dysfunction compared with normotensives, suggesting that diastolic dysfunction is associated with atrial electromechanical abnormalities

Optimal Cooperative Cognitive Relaying and Spectrum Access for an Energy Harvesting Cognitive Radio: Reinforcement Learning Approach

In this paper, we consider a cognitive setting under the context of cooperative communications, where the cognitive radio (CR) user is assumed to be a self-organized relay for the network. The CR user and the PU are assumed to be energy harvesters. The CR user cooperatively relays some of the undelivered packets of the primary user (PU). Specifically, the CR user stores a fraction of the undelivered primary packets in a relaying queue (buffer). It manages the flow of the undelivered primary packets to its relaying queue using the appropriate actions over time slots. Moreover, it has the decision of choosing the used queue for channel accessing at idle time slots (slots where the PU's queue is empty). It is assumed that one data packet transmission dissipates one energy packet. The optimal policy changes according to the primary and CR users arrival rates to the data and energy queues as well as the channels connectivity. The CR user saves energy for the PU by taking the responsibility of relaying the undelivered primary packets. It optimally organizes its own energy packets to maximize its payoff as time progresses

Designing a reading literacy curriculum for secondary school students in Egypt

The key contribution of this research is to produce a proposal for a reading literacy curriculum design (RLCD) for secondary school students (15-17 year-old) in Egypt. This proposal includes four major components: targets, assessment, instruction, and content. Two complementary dimensions are investigated: the theoretical analysis (the researcher’s perspective based upon analysis of reading literacy research) and the fieldwork (the empirical study using a questionnaire for teachers and supervisors and a semi-structured interview for other professionals). Those two dimensions are charted through seven chapters and introduction to and conclusion of these chapters. Following an introduction to the research problem, purposes, questions, structure, rationale, and parameters, the successive focus of these chapters is on: - Clarifying the Egyptian context in terms of education system, culture of learning, critical analysis of the actual reading situation and how all of these elements reveal the gap between 'what is' and 'what ought to be' in RLCD in the secondary school in Egypt (Chapter one);- Reading literacy theory: the concept of reading literacy, dimensions, and models and how these can be used a baseline for RLCD (Chapter two);- Theoretical analysis of reading literacy targets and assessment, the first two components of RLCD (Chapter three);- Theoretical analysis of reading literacy instruction and content, the other two components of RLCD (Chapter four);- Research methodology, where survey design was employed and mixed methods were used: a questionnaire and a semi-structured interview. The major aim was to collect data to find out if the practitioners (i.e. secondary school teachers and supervisors) and other professionals (i.e. specialists in curriculum and instruction) in Egypt agree with the reading literacy research (chapter five);- Data analysis, where a descriptive statistical analysis was conducted for data provided by the questionnaire and a cross-sectional or code and retrieve analysis strategy was applied for data provided by the semi-structured interview. Results indicated that the practitioners' perceptions on the questionnaire and the professionals' answers in the semi-structured interview supported what was revealed by the theoretical analysis regarding RLCD. This suggests that the proposed RLCD is a practical proposition and it is timely to do it. It also raises the confidence in RLCD by triangulation of data by using the questionnaire for the practitioners and the semi-structured interview for other professionals and relating all of this to literature analysis (Chapter six);-Developing the proposal (RLCD): its scope, framework, and components: targets, assessment, instruction, and content. The researcher combines all sources of data: the theoretical analysis, the questionnaire data, and the semi-structured interview data (Chapter seven).The conclusion of the research is introduced. It presents a summary of the research and most importantly, it provides a summary of the contribution of the present research to reading literacy curriculum in theory and practice. Deriving from its results, some recommendations for practice and further research are made and a closing reflective epilogue on the research and the researcher is provided

Simulation Study on IWAG Assisted by Low Salinity Water Injection for Light Oil Reservoirs

Water alternating gas (WAG) injection is a widely practiced Enhanced Oil Recovery (EOR) technique for light oil reservoirs. On the other hand, various researches have documented that using the Smart water concept can further enhance the oil recovery obtained from water-flooding. Although, there was extensive researches conducted on each of the WAG and the smart water techniques separately, yet there are a very few researches conducted on using the smart water concept as the injection water in WAG technique. Previous laboratory core flooding researches have shown that reducing the salinity of the injection water in miscible WAG process would decrease the ultimate oil recovery. The published literature attributed that to the fact that reducing the salinity of the injection water would increase the solubility of the injected gas in water and thus reducing the amount of available gas to be soluble in oil. Reservoir simulation processes were utilized in order to study the effect of using the smart water as the injection water in IWAG technique for light oil reservoirs. A synthetic model with 7,500 grid cells was used to evaluate the performance of several injection scenarios involving low salinity water and WAG techniques under the conditions of light oil reservoir at the depth of -6,000 ft. with oil API of 45°. The thickness of the reservoir is 30 ft. The simulated results showed that using low salinity water as the injection water in immiscible WAG process would increase the oil recovery by 3.5% of the original oil in place (OOIP) than when using conventional high salinity water for light oil reservoirs. The results obtained from the simulation processes do not contradict the laboratory experiments results because of two main reasons. The first reason is that the simulation operations were based on immiscible WAG processes while the core flooding experiments were based on miscible WAG processes, and the second one is due to the gravity effects. During core flooding operations, gravity effects are minimal, while it was taken in consideration during the simulation processes. Another important discovery by the reservoir simulation operations is that using a slug of low salinity water followed by high salinity drive water has much higher recoveries than conventional high salinity water flooding, and that adjusting the slug size can obtain recoveries almost as high as continuous low salinity water injectio