1,768 research outputs found

    Aerosol scattering of ultraviolet sunlight in the tropical maritime atmosphere

    Get PDF
    The effects of atmospheric aerosol scattering on the vertical profile of solar ultraviolet radiation are investigated. Measurements of diffuse and total ultraviolet radiation were made using a rocketborne optical sonde in the marine atmosphere of Antigua. During observations, the sun was at zenith. Vertical profiles of directly transmitted solar radiation were calculated by subtraction of the diffuse component from the total radiance. Using these values of direct downward solar UV-flux, the optical thickness of the atmosphere was derived as a function of altitude. Absorption by ozone was also considered. In the troposphere the values of observed optical thickness were in general equal to or lower than those expected theoretically from Rayleigh scattering alone. The measured radiation profiles were compared with those computed for a multiple scattering model atmosphere. Some computations regarding the interaction of UV-sunlight with maritime aerosols are presented

    Dynamic evolving neural fuzzy inference system equalization scheme in mode division multiplexer for optical fiber transmission

    Get PDF
    The performance of optical mode division multiplexer (MDM) is affected by inter-symbol interference (ISI), which arises from higher-order mode coupling and modal dispersion in multimode fiber (MMF). Existing equalization algorithms in MDM can mitigate linear channel impairments, but cannot tackle nonlinear channel impairments accurately. Therefore, mitigating the noise in the received signal of MDM in the presence of ISI to recover the transmitted signal is important issue. This paper aims at controlling the broadening of the signal from MDM and minimizing the undesirable noise among channels. A dynamic evolving neural fuzzy inference system (DENFIS) equalization scheme has been used to achieve this objective. Results illustrate that nonlinear DENFIS equalization scheme can improve the received distorted signal from an MDM with better accuracy than previous linear equalization schemes such as recursive‐least‐square (RLS) algorithm. Desirably, this effect allows faster data transmission rate in MDM. Additionally, the successful offline implementation of DENFIS equalization in MDM encourages future online implementation of DENFIS equalization in embedded optical systems

    Language-in-education policy and planning : the case of Lebanon

    Get PDF
    Recent changes in Lebanon's educational legislation indicate a shift away from using the national language, Arabic, as a medium of instruction in favour of other foreign languages, namely English, French, and German. The latest decree that was passed in 1994 stipulated that these foreign languages can be used as instructional languages in all cycles, including the pre-school and elementary levels. The issue of language-in-education in Lebanon is an old one, dating back to the arrival of foreign missionaries during the second half of the 17th century. Since then several policies and decisions have been made by the colonial powers and the successive Lebanese governments. This paper reviews these policies and decisions in the light of the country's political history with special emphasis on their impact on students and communities at the socioeconomic, educational and political levels. The paper maintains that the policies made by the French during their mandate over Lebanon (1920-1943) favoured the Christian Catholic and Maronite communities. Meanwhile, the policies adopted by the successive Lebanese governments in the era of independence (1943-1975) were largely improvised and more of responses to emotions triggered by independence. Consequently, several socio-economic and educational incentives determined the spread of foreign languages, especially English, in contemporary Lebanon. This widened the gaps among the classes that make up Lebanese society and contributed to the distribution of quality education along sectarian and socioeconomic lines.peer-reviewe

    The Cholesterol Lowering Effects of Eurycoma Longifolia Jack (Tongkat Ali) Root Extract in Male Rats

    Get PDF
    Background: To investigate the effect of Eurycoma longifolia Jack root extract on serum lipids in rats. Methods: Twenty-six mature male albino Wistar rats were used in this study. A group of 18 rats were fed a high fat and high cholesterol diet for 4 weeks, after which their lipid profile was compared to the control group, who were kept on a normal diet. The rats were then further divided into three groups, the Cf group that continued to feed on a high fat and cholesterol diet only, and group A and group B who continued on a high fat diet with the addition of 5 mg/kg and 10 mg/kg of Eurycoma longifolia Jack root extract respectively for 4 weeks. After the 4 week period, the rat's lipid profiles were analysed again. Results: Group A and B showed significant total cholesterol reduction when compared to the Cf group, 140 ± 7.23, 139.63 ± 7.95, 192.14 ± 8.96 mg/dL respectively (p < 0.001). The total cholesterol/HDL ratio in group A was 5 however there was a sharp increase in group B to a high-risk level of 9.2 indicating a significant drop in HDL levels. The LDL level increased significantly in both group A and B compared to the Cf group. Conclusions: Eurycoma longifolia Jack root extract is effective in lowering total cholesterol, however the dose needs to be adjusted to prevent an excessive decrease in HDL levels

    Speech recognition system based on Hidden Markov Model concerning the Moroccan dialect DARIJA

    Get PDF
    In this work, we present a system for automatic speech recognition on the Moroccan dialect. We used the hidden Markov model to model the phonetic units corresponding to words taken from the training base. The results obtained are very encouraging given the size of the training set and the number of people taken to the registration. To demonstrate the flexibility of the hidden Markov model we conducted a comparison of results obtained by the latter and dynamic programming

    Predicting Avian Influenza Co-Infection with H5N1 and H9N2 in Northern Egypt.

    Get PDF
    Human outbreaks with avian influenza have been, so far, constrained by poor viral adaptation to non-avian hosts. This could be overcome via co-infection, whereby two strains share genetic material, allowing new hybrid strains to emerge. Identifying areas where co-infection is most likely can help target spaces for increased surveillance. Ecological niche modeling using remotely-sensed data can be used for this purpose. H5N1 and H9N2 influenza subtypes are endemic in Egyptian poultry. From 2006 to 2015, over 20,000 poultry and wild birds were tested at farms and live bird markets. Using ecological niche modeling we identified environmental, behavioral, and population characteristics of H5N1 and H9N2 niches within Egypt. Niches differed markedly by subtype. The subtype niches were combined to model co-infection potential with known occurrences used for validation. The distance to live bird markets was a strong predictor of co-infection. Using only single-subtype influenza outbreaks and publicly available ecological data, we identified areas of co-infection potential with high accuracy (area under the receiver operating characteristic (ROC) curve (AUC) 0.991)

    Secrecy and performance models for query processing on outsourced graph data

    Get PDF
    Database outsourcing is a challenge concerning data secrecy. Even if an adversary, including the service provider, accesses the data, she should not be able to learn any information from the accessed data. In this paper, we address this problem for graph-structured data. First, we define a secrecy notion for graph-structured data based on the concepts of indistinguishability and searchable encryption. To address this problem, we propose an approach based on bucketization. Next to bucketization, it makes use of obfuscated indexes and encryption. We show that finding an optimal bucketization tailored to graph-structured data is NP-hard; therefore, we come up with a heuristic. We prove that the proposed bucketization approach fulfills our secrecy notion. In addition, we present a performance model for scale-free networks which consists of (1) a number-of-buckets model that estimates the number of buckets obtained after applying our bucketization approach and (2) a query-cost model. Finally, we demonstrate with a set of experiments the accuracy of our number-of-buckets model and the efficiency of our approach with respect to query processing

    Learning Organization and Intellectual Capital: An Empirical Study of Jordanian Banks

    Get PDF
    The purpose of this paper is to investigate empirically the relation between the learning organization andintellectual capita Jordanian banking industry. The intellectual capital is measured by three dimensions,namely, human capital, structural capital, and customer capital. 86 Questionnaires are sent to managers andexecutives in Jordanian banks headquarters using convenience sample, however, 66 questionnaires werereturned and the response rate is 77%. Quantitative approach is employed to test the proposed researchhypotheses; correlation analysis and regression analysis are conducted. The results support the hypothesisthat learning organization has a positive impact on banks intellectual capital. The results extend theunderstanding of the role of organizational learning in creating intellectual capital and building sustainableadvantages for banks in emerging economies.Keywords: Banking Industry, Intellectual Capital, Learning Organizations, Hypotheses Testing, Jordan

    PROGRAM PELATIHAN TATA RIAS DALAM MENINGKATKAN KETERAMPILAN WARGA BINAAN DI LEMBAGA PEMASYARAKATAN PEREMPUAN KELAS II A SAMARINDA

    Get PDF
    Penelitian ini bertujuan untuk menganalisis penyelengaraan program pelatihan keterampilan tata rias bagi warga binaan lembaga pemasyarakatan kelas II A perempuan Samarinda. Penelitian ini menggunakan pendekatan penelitian kualitatif karena sesuai dengan tujuan penelitian yaitu menganalisis lebih dalam pelaksanaan pelatihan. Pengumpulan data menggunakan teknik wawancara, observasi dan studi dokumen. Analisis data dengan menggunakan teknik analisis data berupa reduksi data, penyajian data, dan penarikan kesimpulan. Hasil penelitian menunjukkan bahwa penelitian dilaksanakan melaui tahapan program. Tahapan awal berupa perencanaan untuk menyiapkan program pelatihan. Pada tahapan ini dilaksanakan identifikasi kebutuhan untuk menentukan kebutuhan belajar sebagai dasar dalam perencanaan program. Selanjutnya penyiapan instruktur program pelatihan sebagai pendidik pada kegiatan pelatihan. Tahapan pelaksanaan dilaksanakan dengan proses pembelajaran antara pendidik yaitu instruktur dan warga binaan. Proses pelaksanaan dilaksanakan dengan menggunakan metode ceramah dan metode praktek. Evaluasi program dilaksanakan pada saat peserta program atau warga binaan melaksanakan praktek
    corecore