Discrete Rogue waves in an array of waveguides

We study discrete rogue waves in an array of nonlinear waveguides. We show that very small degree of disorder due to experimental imperfection has a deep effect on the formation of discrete rogue waves. We predict long-living discrete rogue wave solution of the discrete nonlinear Schrodinger equation.Comment: To Appear in PL

Continuous Wavelet Transform and Hidden Markov Model Based Target Detection

Standard tracking filters perform target detection process by comparing the sensor output signal with a predefined threshold. However, selecting the detection threshold is of great importance and a wrongly selected threshold causes two major problems. The first problem occurs when the selected threshold is too low which results in increased false alarm rate. The second problem arises when the selected threshold is too high resulting in missed detection. Track-before-detect (TBD) techniques eliminate the need for a detection threshold and provide detecting and tracking targets with lower signal-to-noise ratios than standard methods. Although TBD techniques eliminate the need for detection threshold at sensor’s signal processing stage, they often use tuning thresholds at the output of the filtering stage. This paper presents a Continuous Wavelet Transform (CWT) and Hidden Markov Model (HMM) based target detection method for employing with TBD techniques which does not employ any thresholding

Stochastic Dominance in Mobility Analysis

This paper introduces a technique for mobility dominance and compares the degree of earnings mobility of men in the USA from 1970 to 1995. The highest mobility is found in the 1975–1980 or 1980–1985 periods

Acid Rain in Niger Delta Region: Implication on Water Resources Quality and Crisis

This research focused on the effect of acid rain on the water quality of the Niger Delta region of Nigeria. Three hundred water samples were collected: 100 water samples from rain, 100 from open wells and 100 from rivers. The water samples were analysed using the paired t-test and multiple correlation analysis to ascertain their level of variation and relationship. Hydrochemical analysis revealed moderately low pH values of 4.98 > 5.12 > 5.23 for rain, river and well water resources in the Niger Delta region. The anions, cations and microbiological characteristics in river and well water sources before rain events were generally greater after down pours. This indicates that the pH values of rain water resources correlated significantly (r = 0.80) with gas flaring, an activity connected with petroleum exploration activities in the Niger Delta region. The acid content in the rainwater not only lowers the quality of rainwater sources for domestic use, but also the quality of well and river water sources in the region. This has led to acute drinking water shortages in the region and has exacerbated struggles for the few existing clean water sources. The cessation of gas flaring as well as the provision of adequate potable water supply to locals is highly recommended. Additionally liming of the water resources and other methods of cleansing acidic water may be employed in the interim.Keywords: Acid rain, well, river and water crisi

The Role of Dialogue in the Search for National Security in the Face of Boko Haram Phenomenon: a Case Study of 2 Samuel 20:16-22

The coordinated and unrelenting attacks by the Boko Haram sect in the northern states of Bornu, Yobe, Gombe, Bauchi, Niger, and Adamawa which have claimed several lives, besides making life miserable for Nigerians, remain a threat to national security and survival. Although efforts have been made to curtail the menace, the quest for security of lives and properties is still elusive. Could this menace of insecurity be regarded as ethno-religio-political? This work explores the role of dialogue in the search for National Security as premised on its antecedent case of 2 Samuel 20:16-22. The problem of insecurity in ancient Israel arose from insensitivity of the Judahites which aroused the grievance of the Northern tribes (2 Samuel 19:41-44), leading to the revolt of Sheba, who realizing the implications of his actions, fled to Abel of Beth-maacah where dialogue between Joab and a wise woman brought the war to a satisfactory end though with minimum casualties. One may therefore conclude that dialogue is a way forward. The lingering security threat in Nigeria can be resolved through an effort geared towards probing into the fundamental reason(s) for the spate of violence in the country. Unless genuine dialogue is adopted, Nigeria may end up treating the symptoms rather than arresting the real cause(s) of the problem. Keywords: Security, Boko Haram, dialogue, insurgents, violence, peaceful co-existenc

Seasonal Variations of Physico-chemical Characteristics in Water Resources Quality in Western Niger Delta Region, Nigeria

The influence of seasonal changes on the physico-chemical characteristics of water resources quality in the western horn of the Niger Delta region of Nigeria has been investigated. The water resources investigated were rain, open well and borehole water. The seasonal temperature variations show the waters to be in a heterothermal phase, but values are not significantly different (P< 0.05). The pH of the water resources is acidic in nature with pH values < 5.50 at all seasons. In general, the data revealed that maxima and minima concentrations of the priority physico-chemical water quality parameters examined in the three water resources are either above or below the target water quality range (TWQR) for domestic use, making these three water resources available in the area a potential health hazards to inhabitant. The overall implication of this observation calls for an urgent water resources management strategy in the area in order to circumvent the fast deteriorating water resources quality, which may pose associated health risk and environmental hazards. @JASE

Online Identification of Stochastic Continuous-Time Wiener Models Using Sampled Data

It is well known that ignoring the presence of stochastic disturbances in the identification of stochastic Wiener models leads to asymptotically biased estimators. On the other hand, optimal statistical identification, via likelihood-based methods, is sensitive to the assumptions on the data distribution and is usually based on relatively complex sequential Monte Carlo algorithms. We develop a simple recursive online estimation algorithm based on an output-error predictor, for the identification of continuous-time stochastic parametric Wiener models through stochastic approximation. The method is applicable to generic model parameterizations and, as demonstrated in the numerical simulation examples, it is robust with respect to the assumptions on the spectrum of the disturbance process

1 mJ pulse bursts from a Yb-doped fiber amplifier

Cataloged from PDF version of article.We demonstrate burst-mode operation of a polarization-maintaining Yb-doped fiber amplifier capable of generating 60 mu J pulses within bursts of 11 pulses with extremely uniform energy distribution facilitated by a novel feedback mechanism shaping the seed of the burst-mode amplifier. The burst energy can be scaled up to 1 mJ, comprising 25 pulses with 40 mu J average individual energy. The amplifier is synchronously pulse pumped to minimize amplified spontaneous emission between the bursts. Pulse propagation is entirely in fiber and fiber-integrated components until the grating compressor, which allows for highly robust operation. The burst repetition rate is set to 1 kHz and spacing between individual pulses is 10 ns. The 40 mu J pulses are externally compressible to a full width at half-maximum of 600 fs. However, due to the substantial pedestal of the compressed pulses, the effective pulse duration is longer, estimated to be 1.2 ps. (C) 2012 Optical Society of Americ

A Subgroup Decomposable Measure of Relative Income Mobility

income mobility, relative mobility measures, subgroup decomposability