Design of an adaptive neural predictive nonlinear controller for nonholonomic mobile robot system based on posture identifier in the presence of disturbance

This paper proposes an adaptive neural predictive nonlinear controller to guide a nonholonomic wheeled mobile robot during continuous and non-continuous gradients trajectory tracking. The structure of the controller consists of two models that describe the kinematics and dynamics of the mobile robot system and a feedforward neural controller. The models are modified Elman neural network and feedforward multi-layer perceptron respectively. The modified Elman neural network model is trained off-line and on-line stages to guarantee the outputs of the model accurately represent the actual outputs of the mobile robot system. The trained neural model acts as the position and orientation identifier. The feedforward neural controller is trained off-line and adaptive weights are adapted on-line to find the reference torques, which controls the steady-state outputs of the mobile robot system. The feedback neural controller is based on the posture neural identifier and quadratic performance index optimization algorithm to find the optimal torque action in the transient state for N-step-ahead prediction. General back propagation algorithm is used to learn the feedforward neural controller and the posture neural identifier. Simulation results show the effectiveness of the proposed adaptive neural predictive control algorithm; this is demonstrated by the minimised tracking error and the smoothness of the torque control signal obtained with bounded external disturbances

Improving shared access to Cloud of Things resources.

Cloud of Things (CoT) is an emerging paradigm that integrates Cloud Computing and Internet of Things (IoT) to support a wide range of real-world applications. Resource allocation plays a vital role in CoT, especially when allocating IoT physical resources to Cloud-based applications to ensure seamless application execution. Due to the heterogeneity and the constrained capacities of IoT resources, resource allocation is a challenge. This complexity leads to missing/limiting shared access to the IoT physical resources and consequently lessen the reusability of the resources across multiple applications. This issue results in, 1) replicating IoT deployments making them expensive and not feasible for many prospective users, 2) existing IoT infrastructures are over-provisioned to meet the unpredictable application requirements in which resources may be significantly underutilised, and 3) the adoption of CoT is slowed. Improving shared access to CoT resources can provide efficient resource allocation, improve resource utilisation and likely to reduce the cost of IoT deployments. Existing solutions include small-scale, hardware and platform-dependent mechanisms to enable or improve shared access to IoT resources. The research presented in this thesis considers trading CoT resources in a marketplace as an approach to improve shared access to CoT resources. It proposes a solution to Cot resource allocation that re-imagines CoT resources as commodities that can be provided and consumed by the marketplace participants. The novel contributions of the research presented in this thesis are summarised as follows: 1) a model to describe and quantify the value of CoT resources, 2) a resource sharing and allocation strategy called Exclusive Shared Access (ESA) to CoT resources, 3) a QoS-aware optimisation model for trading CoT resources as a single and multipleobjective optimisation problem, and 4) a marketplace architecture and experimental evaluation to verify its performance and scalability

Steam reforming of biomass tar over tyre char for hydrogen production

Carbonaceous materials have been proven to have a high activity for tar removal. The simultaneous gasification of pyrolysis gases and char has a significant role in increasing the gas yield and decreasing the tar in the product syngas. This study investigates the use of tyre char as a catalyst for hydrogen production and tar reduction during the pyrolysis/reforming of biomass using a two stage fixed bed reactor. The biomass sample was pyrolysed under nitrogen at a pyrolysis temperature of 500 deg;C. The evolved pyrolysis volatiles were passed to a second stage with steam and the gases were reformed at a temperature of 900 deg;C with the presence of tyre char as catalyst. The influence of catalyst bed temperature, steam flow rate, reaction time and addition of metals were investigated. Char was characterized using BET surface analysis and scanning electron microscopy (SEM). Raising the steam injection rate and reforming temperature resulted in an increase in hydrogen production as steam reforming and gasification of char increased. Over the ranges of operating conditions examined, the maximum hydrogen content reached 52% and the ratio of H 2 /CO varied between 1.3 to 2. The presence of steam promotes the char conversion, however, increasing the amount of steam from 6.64 g/h to 8.64 g/h doesn't contribute to decrease the char yield and the obtained hydrogen yield was almost the same at about 51 vol. %. The results indicate that the char bed exhibited a higher tar reduction than the thermal cracking conditions

Capillary trapping of CO2 in oil reservoirs: observations in a mixed-wet carbonate rock

Early deployment of carbon dioxide storage is likely to focus on injection into mature oil reservoirs, most of which occur in carbonate rock units. Observations and modeling have shown how capillary trapping leads to the immobilization of CO2 in saline aquifers, enhancing the security and capacity of storage. There are, however, no observations of trapping in rocks with a mixed-wet-state characteristic of hydrocarbon-bearing carbonate reservoirs. Here, we found that residual trapping of supercritical CO2 in a limestone altered to a mixed-wet state with oil was significantly less than trapping in the unaltered rock. In unaltered samples, the trapping of CO2 and N2 were indistinguishable, with a maximum residual saturation of 24%. After the alteration of the wetting state, the trapping of N2 was reduced, with a maximum residual saturation of 19%. The trapping of CO2 was reduced even further, with a maximum residual saturation of 15%. Best-fit Land-model constants shifted from C = 1.73 in the water-wet rock to C = 2.82 for N2 and C = 4.11 for the CO2 in the mixed-wet rock. The results indicate that plume migration will be less constrained by capillary trapping for CO2 storage projects using oil fields compared with those for saline aquifers

Biological control agent for mosquito larvae: Review on the killifish, Aphanius dispar dispar (Rüppel, 1829)

This review attempts to give an account on the recent advances on the killifish Aphanius dispar dispar as a biological control agent for mosquito larvae. Thirty six (36) articles of literature (scientific papers, technical and workshop reports) on this subject covering the period between 1980 and 2009 were reviewed. The larviciding process by using chemicals to control mosquitoes in the past resulted in a very harmful effects on the environment (bioaccumulation of DDT), resistance of mosquito vectors, destruction of non-target organisms and human health hazards. Biological control of mosquito larvae by using fish has shown many advantages over chemicals, but exogenous fishes such as Gambusia affinis may have negative effects on fishes and destroy the local habitat. Eco-friendly indigenous larvivorous fish with less harm to the environment and the local fish fauna is suitable for biological control of mosquito larvae. Furthermore, A. dispar is capable of natural and artificial reproduction to maintain a fish stock in order to eliminate mosquito larvae and protect people from many mosquito borne diseases such as malaria, dengue, rift valley fever (RVF), encephalitis and many others (Suliman, 2010). Hence, the indigenous killifish, A. dispar is found to play this role effectively and efficiently. Problems associated with its artificial breeding and fungal infection of its eggs can be further investigated. In addition to this, integrated methods of biological control should be carried out in order to reach the best targets of mosquito control.Key words: Biological control, mosquito larvae, indigenous fish, Aphanius dispar

Modelling of Implantable Drug Delivery System in Tumor Microenvironment Using Molecular Communication Paradigm

© 2013 IEEE. Local delivery of anticancer drug in tumor using miniaturized implants over a prolonged period of time is a powerful treatment strategy that provides lower toxicity and higher drug bioavailability compared to conventional systemic chemotherapy. Prediction of anticancer drug distribution in tumor following implantation of the drug implant is necessary to improve and optimize the implantable drug delivery systems (IDDSs). In this paper, we develop mathematical and stochastic simulation models for the prediction of spatiotemporal concentration of anticancer doxorubicin following implantation of a dual-release implant in an isolated tumor microenvironment (TME). Our model utilizes mathematical convolution of the channel impulse response (CIR) with the drug release function based on the abstraction of molecular communication. The derived CIR can be used to obtain drug concentration profile in the surrounding tissue for various release profiles and different anticancer drugs. We derive closed-form analytical expression for anticancer drug concentration. The required release rates are obtained by fitting the experimental data on dual-release implant available in the literature to a mathematical expression. In addition, we also present a particle-based stochastic simulator and compare the results with those predicted by the analytical model. The accuracy of predictions by both the models is further verified by comparing with the published experimental data in the literature. Both the proposed models can be useful for the design optimization of the implantable drug delivery systems (IDDSs) in tumors and other tissues and can potentially reduce the number of animal experiments thus saving cost and time

Modelling of multilayer biological medium under molecular communication paradigm

© 2017 IEEE. Molecular communication is an emerging paradigm that enables both the biological and synthetic nanomachines to communicate with each other within an aqueous biological environment such as the communication between living cells. Prediction of the number of drug molecules near a target site, e.g., tumor cells, is very important for determining the required drug dosages to increase positive therapeutic outcomes. In this paper, we derive an analytical expression for the received molecular signal in a multilayered biological environment. We also present development of particle-based simulator. We find the analytical results for three-layer biological medium compares well with the simulation results. The effect of the diffusion coefficient and the distance between the transmitter and the receiver (e.g., targeted cells) are also investigated

Histopathology of gastric cancer in Yemen: A seven years retrospective analysis

Background: Gastric cancer (GC) is a major contributor to the global burden of cancer morbidity and mortality. It is the fourth most commonly occurring worldwide.Objective: To describe the general pattern of primary GC in Yemen and compare the findings of patients' age, sex, histological type and degree of differentiation to findings from other Middle Eastern countries and the rest of the world.Methods: This is a descriptive record-based study of 517 cases of GC in the Department of pathology, Sana'a University, Yemen, for seven years period. The diagnosis was made on hematoxylin and eosin stained sections and categorized the cases of gastric malignancies according to histological type.Results: Out of 517 cases of GC, 183 (35.4%) were females and 286 (64.6%) were males with 1:1.8 female to male ratio. The commonest type of GC was adenocarcinoma comprising, 462 (89.3%) of which female and male cases were 166 (36%) and 296 (64%) respectively. Non-Hodgkin's lymphomas accounted, for 38 (7.4%). The rest of the cases were nine undifferentiated malignancies, four leiomyosarcoma, two gastrointestinal malignant stromal tumors, one adenosquamous and the last one was carcinoid. Male preponderance was seen in all malignancies. The mean age for adenocarcinoma in females was 55.9 years and 59.5 years in males. Well-differentiated adenocarcinomas accounted for 45.7% followed by moderately-differentiated 22.1%. The poorly differentiated and signet ring cell carcinomas accounted for 16.2% and 9.5% respectively.Conclusion: The frequency of GC in Yemen revealing similar features in age, sex and hitological types with that reported from high incidence areas.Key words: Gastric cancer - adenocarcinoma- lymphoma - Yemen

A randomized trial of nebulized 3% hypertonic saline with salbutamol in the treatment of acute bronchiolitis in hospitalized infants

OBJECTIVE: Acute bronchiolitis is a common disorder of infants that often results in hospitalization. Apart from supportive care, no therapy has been shown to influence the course of the disease, except for a possible effect of nebulized hypertonic saline (HS). To determine whether this does have beneficial effects on length of stay in hospital or on severity scores, we undertook a double-blind, randomized, controlled trial in a pediatric department of a Portuguese hospital. METHODS: Previously healthy infants, younger than 12 months, hospitalized with mild-to-moderate acute viral bronchiolitis were randomized to receive either nebulized 3% (hypertonic, HS) or 0.9% (normal, NS) saline during their entire hospital stay. Primary endpoints were: length of hospital stay and severity scores on each day of hospitalization. Need for supplemental oxygen, further add-on medications and adverse effects were also analyzed. RESULTS: Sixty-eight patients completed the study (HS: 33; NS: 35). The median length of hospital stay did not differ between groups: HS: 5.6 ± 2.3 days; NS: 5.4 ± 2.1 days (P = 0.747). We found no difference between groups in severity scores from day 1 to day 4. There were no differences in need for supplemental oxygen or add-on medications. Patients in HS group had significantly more cough (46% vs. 20%, P = 0.025) and rhinorrhoe (58% vs. 31%, P = 0.30). CONCLUSION: This study does not support the use of nebulized HS over NS in therapy of hospitalized children with mild-to-moderate acute viral bronchioliti