Full-Duplex Systems Using Multi-Reconfigurable Antennas

Full-duplex systems are expected to achieve 100% rate improvement over half-duplex systems if the self-interference signal can be significantly mitigated. In this paper, we propose the first full-duplex system utilizing Multi-Reconfigurable Antenna (MRA) with ?90% rate improvement compared to half-duplex systems. MRA is a dynamically reconfigurable antenna structure, that is capable of changing its properties according to certain input configurations. A comprehensive experimental analysis is conducted to characterize the system performance in typical indoor environments. The experiments are performed using a fabricated MRA that has 4096 configurable radiation patterns. The achieved MRA-based passive self-interference suppression is investigated, with detailed analysis for the MRA training overhead. In addition, a heuristic-based approach is proposed to reduce the MRA training overhead. The results show that at 1% training overhead, a total of 95dB self-interference cancellation is achieved in typical indoor environments. The 95dB self-interference cancellation is experimentally shown to be sufficient for 90% full-duplex rate improvement compared to half-duplex systems.Comment: Submitted to IEEE Transactions on Wireless Communication

L[infinity sign]- norm problem and mid-range polish

The L(,(INFIN))-norm has been widely studied as a criterion of curve fitting problems. We are interested in the best L(,(INFIN))-approximation to a given finite array of number A = (a(,ij))(,mXn), i.e.;A natural iterated polishing (Mid-Range Polish) algorithm is shown, and its convergence in the L(,(INFIN))-norm is proved. Since the conver- gence of the Mid-Range Polish algorithm may take infinitely many iterations, we developed a new algorithm which converges in a finite number of steps to an optimal matrix of residual A* = (a(,ij)-r(,i)*-s(,j)*)(,mXn), whose L(,(INFIN))-norm u is the minimum one.;Several conditions are obtained, each of which is necessary and sufficient for a given matrix of residual to be optimal. For instance, a matrix of residual is optimal if and only if the set of entries, which equal to the L(,(INFIN))-norm of the matrix u in absolute value, contain a loop L alternating the value of u and -u. This criterion leads to an elegant and efficient finite algorithm for calculating the best L(,(INFIN))-approximation. Examples and results of the computational experience with a computer code version of some of the algorithms are presented

Toxico-histological Effects of Sublethal Concentrations of Lead Nitrate on the Gills of the African Catfish, Clarias gariepinus

170-175This study aimed to investigate the effects of subleathal lead doses on the histological architecture of gills in the freshwater African catfish, Clarias gariepinus. Results revealed three stages of changes after exposure to three doses of lead nitrate. The changes were mild in fish exposed to 16.12 mg/L of Pb (NO3)2 (stage I 20% of LC50) and severe in case of 40% of LC50 (stage II, 32.24 mg/L) and 60% of LC50 (stage III 48.37% mg/L) in comparison to control. The histological examination revealed normal architecture of gills in control fish. Normal gills were characterized with primary gill lamellae with a central hyaline cartilage. However, three-stage changes were observed after exposure to the three doses of lead nitrate. In stage I, a cartilaginous matrix appeared along with loosening of the epithelial lining of the cartilaginous core and abundant vascular spaces were observed on the secondary gill lamellae. An extra cartilaginous matrix, loosening of the epithelial lining of the cartilaginous core, de-shaped gill lamellae, and degeneration of the secondary gill lamellae were noted in stage II. Lesions in the gill pattern in stage III were represented by shortening of the tips of secondary gill lamellae, damaged gill lamellae, a cartilaginous matrix, and hyperplasia. This indicated that lead exposure resulted in severe histopathological changes in the gills in a dose-dependent manner

A rare neurocutaneous syndrome and a rare association

Among the many causes of ataxia, Ataxia -telangictasia is an autosomal recessive1, multi system disease affecting the skin, nervous system & immune system. It's prevalence has been estimated at 1 to 2 per 100,000 It is a neurodegenerative disorder2 in which there is progressive cerebellar ataxia, occulocutaneous telangictasias, chronic sinopulmonary disease & high incidence of malignancy associated with variable humoral & cellular immuno deficiency. The abnormal gene has been mapped to the long arm of chromosome 11 (ATM gene)3 . Carriers has increased sensitivity to ionizing radiation4. Telangicatsias tends to develop between the ages of 3-6 years. It also affects the ears, eye lids immunologic abnormality is selective absence of IgA found in 50-80 % ,IgG may also be affected. The T cells percentage is reduced in total & T Helper (CD4) phenotype, with normal or increased percentages of the Suppressor ( CD8). Hodgkin's, non Hodgkin's lymphoma5 & leukemia6  develops in 10 % of cases6 . Other variable body tumors may occur. These patients may become critically ill and need intense care to prevent serious complications or death7. The syndrome is associated with abnormal IgA levels with a higher risk of blood malignancies like lymphoma or leukaemia, patients may have telangiectasia else were in the body specially the upper respiratory tract. The is a case report about one of this rare neuro- cutaneous syndromes which was reported in Khartoum Sudan. Consent from the parents was taken for the purpose of publication and teaching.Keywords: Ataxia telangiectasia, Sudan, Rare associatio

Subclinical hypothyroidism ups the risk of vascular complications in type 2 diabetes

The incidence of thyroid dysfunction in diabetic patients is higher than that of the general population. Undiagnosed thyroid dysfunction may affect the metabolic control and enhance cardiovascular, and other chronic complication risks in diabetic patients. Few studies have examined the relationship between subclinical hypothyroidism (SCH) and vascular complications of type 2 diabetes.Objectives: To find out the relationship between SCH and vascular complications in patients with Type 2 diabetes. Subjects andMethods: Our cross sectional study included 110 patients with type 2 DM (45 males and 65 females) who were followed at the Diabetes outpatient Clinics in the state of Kuwait during 6 months period. All patients subjected to complete clinical and laboratory data, including thyroid function tests, total cholesterol (TC), triglyceride (TG), HDL-C, LDL-C, urinary albumin, fundus examination, ECG, and Glycosylated hemoglobin.Results: Among 110 patients, 21 (19.1%) Patients had SCH. Patients with SCHwere more significantly older, with longer duration of diabetes, higher HbA1c, total cholesterol and LDL-C than euthyroid group. However, gender (p = 0.076), BMI (p = 0.092), and smoking (P = 0.715) were not significantly different between the SCH and euthyroid groups. The SCH group had a higher prevalence of dyslipidemia (p = 0.017), diabetic nephropathy (p = 0.003) diabetic retinopathy (p = 0.004) and IHD (p = 0.011) than the euthyroid group while no significant difference in the prevalence of diabetic neuropathy (p = 0.420).Conclusions: SCH is a common endocrine disorder in patients with Type 2 diabetes. It could be associated with a higher prevalence of vascular complications in type 2 diabetes. We could not prove a relation between SCH and diabetic neuropathy.Keywords: Subclinical hypothyroidism, Diabetes, Vascular complicatio

Implementation of Adaptive Neural Networks Controller for NXT SCARA Robot System

Several neural network controllers for robotic manipulators have been developed during the last decades due to their capability to learn the dynamic properties and the improvements in the global stability of the system. In this paper, an adaptive neural controller has been designed with self learning to resolve the problems caused by using a classical controller. A comparison between the improved unsupervised adaptive neural network controller and the P controller for the NXT SCARA robot system is done, and the result shows the improvement of the self learning controller to track the determined trajectory of robotic automated controllers with uncertainties. Implementation and practical results were designed to guarantee online real-time

Activation Energy of Surface Diffusion and Terrace Width Dynamics During the Growth of in (4×3) on Si (100) - (2×1) by Femtosecond Pulsed Laser Deposition

The nucleation and growth of indium on a vicinal Si (100) - (2×1) surface at high temperature by femtosecond pulsed laser deposition was investigated by in situ reflection high energy electron diffraction (RHEED). RHEED intensity relaxation was observed for the first ∼2 ML during the growth of In (4×3) by step flow. From the temperature dependence of the rate of relaxation, an activation energy of 1.4±0.2 eV of surface diffusion was determined. The results indicate that indium small clusters diffused to terrace step edges with a diffusion frequency constant of (1.0±0.1) × 1011 s-1. The RHEED specular beam split peak spacing, which is characteristic of a vicinal surface, was analyzed with the growth temperature to obtain the average terrace width. Gradual reduction in the terrace width during growth of In (4×3) was observed with In coverage and is attributed to the detachment of In atoms from terrace edges. At a substrate temperature of 405 °C, the average terrace width decreased from 61±10 Å, which corresponds to the vicinal Si(100) surface, to an equilibrium value of 45±7 Å after deposition of ∼23 ML. Further In coverage showed a transition of the RHEED pattern from (4×3) to (1×1) and the growth of rounded In islands (average height of ∼1 nm and width of ∼25 nm), as examined by ex situ atomic force microscopy. © 2008 American Institute of Physics. [DOI: 10.1063/1.2909923