Underwater channel characterization to design wireless sensor network by Bellhop

Acoustic underwater link due to low attenuation is employed for underwater sensor network (UWSN). Due to water changing physical properties and different environmental conditions, the sound propagation for every underwater channel are different. So, the most important parameters to design reliable UWSN are: the shadow zone determination, optimum nodes placement, high signal to noise ratio and more power efficiency of nodes. This paper simulates underwater channel for 7 KHz carrier frequency, with measured physical water properties and remote sensing data. Based on defined scenario, the research determines optimum nodes placement and link budget analysis based on bottom to surface acoustic link. The paper utilizes Bellhop acoustic toolbox as a simulator, GeoMapApp program to collects bathymetry data and Aviso+ database to determine wind speed on sea surface. As a result the paper based on simulation of sound propagation in channel and transmission loss determination in depth and range, finds the optimum nodes positions and link budget calculation to prove the results

Determination of Melting Layer Boundaries and Attenuation Evaluation in Equatorial Malaysia at Ku-Band

Upsurge in bandwidth demand in recent times for real-time data transmission have put serious constraints on satellite communication channels, leading to congestion of the lower frequency bands; necessitating migration to higher bands (Ku, Ka and V) with attendant problems such as signal fading, depolarization and attenuation due to presence of hydrometeors. There is need to separately account for attenuation due to the melting layer along the earth-space microwave links. One year data from ground-based S-band meteorological radar sourced from Kluang station of the Malaysian Meteorological Department was processed to build the vertical reflectivity of rain profile for UTM, Malaysia. Results from this work suggested that the effects of the melting layer on signal attenuation at Ku-band can be quite significant in the tropical and equatorial regions. It was estimated to be 13.36 dB and 15.44 dB at 0.01% of the time exceeded using Laws-parsons and Marshall-Palmer regression coefficients, respectively. Furthermore, it was observed that ITU-R. P.618-11 model largely under-estimated the attenuation along the slant-paths because of its failure to account for attenuation due to the melting layer in its formulation by its assumption of constant rain rate; thus rendering it unsuitable for rain attenuation predictions in the tropics

An Improved Slant Path Attenuation Prediction Method in Tropical Climates

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R_0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models

Health education and the control of urogenital schistosomiasis: assessing the impact of the Juma na Kichocho comic-strip medical booklet in Zanzibar

Endeavours to control urogenital schistosomiasis on Unguja Island (Zanzibar) have focused on school-aged children. To assess the impact of an associated health education campaign, the supervised use of the comic-strip medical booklet Juma na Kichocho by Class V pupils attending eighteen primary schools was investigated. A validated knowledge and attitudes questionnaire was completed at baseline and repeated one year later following the regular use of the booklet during the calendar year. A scoring system (ranging from 0.0 to 5.0) measured children's understandings of schistosomiasis and malaria, with the latter being a neutral comparator against specific changes for schistosomiasis. In 2006, the average score from 751 children (328 boys and 423 girls) was 2.39 for schistosomiasis and 3.03 for malaria. One year later, the score was 2.43 for schistosomiasis and 2.70 for malaria from 779 children (351 boys and 428 girls). As might be expected, knowledge and attitudes scores for schistosomiasis increased (+0.05), but not as much as originally hoped, while the score for malaria decreased (-0.33). According to a Kolmogorov-Smirnov test, neither change was statistically significant. Analysis also revealed that 75% of school children misunderstood the importance of reinfection after treatment with praziquantel. These results are disappointing. They demonstrate that it is mistaken to assume that knowledge conveyed in child-friendly booklets will necessarily be interpreted, and acted upon, in the way intended. If long-term sustained behavioural change is to be achieved, health education materials need to engage more closely with local understandings and responses to urogenital schistosomiasis. This, in turn, needs to be part of the development of a more holistic, biosocial approach to the control of schistosomiasis

Evidence-based health care in the occupied Palestinian territory: findings from a conference-based preparatory workshop

Background The principles of evidence-based health-care (EBHC) are not widely appreciated in the occupied Palestinian territory. During the past 5 years, interest in EBHC in Gaza has been generated through a series of lectures and workshops run by the EBHC Unit in Gaza. To further promulgate the principles of EBHC in the occupied Palestinian territory and to raise awareness of differences between local practice and best evidence, a 2 day conference was organised in October 2013. In this study our objectives were to promote the principles of EBHC and to improve clinical practice in 15 specific areas of clinical practice. Methods Five subcommittees were established 6 months before the conference that addressed general surgery, medicine, paediatrics, obstetrics, and orthopaedics and neurosurgery. Each subcommittee comprised a senior and a junior specialist and was given 5 months to identify the three most

Chemical constituents and lipoxygenase inhibitory activity of Piper stylosum Miq.

ABSTRACT. Chemical constituents and lipoxygenase inhibitory activity of the aerial part of Piper stylosum have been studied. Fractionation and purification of the extracts afforded five lignans, identified as yangambin (1), sesamin (2), syringaresinol (3), pinoresinol (4), and medioresinol (5), together with other constituents; 4-allyl resorcinol, β-sitosterol, β-sitostenone, taraxerol, vanilin, and vanilic acid. The structures of these compounds were established by analysis of their spectral data, as compared to that of reported compounds. The lipoxygenase inhibitory activity of the extracts and isolated lignans were also evaluated.               KEY WORDS: Piperaceae, Piper, Piper stylosum, Lignan, Lipoxygenase Bull. Chem. Soc. Ethiop. 2019, 33(3), 587-592.   DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

Improved crowd psychological model and control

The behavior of human crowd is an interesting phenomenon in which individuals are set as a collection that comprises of a highly dynamic social group. The crowd behaviors have been investigated by researchers over the years. Recent works include the study in modeling and controlling of the dynamic psychological behavior of crowds such as students’ behavior in a classroom or people’s behavior in a one-dimensional queue. In this paper, an improved version of the psychological crowd model has been proposed, where the social interaction between two individuals in a crowd is represented by a weightage, called the weight of social interaction. It has been shown that the inclusion of the social interaction weight has allowed social interactions between individuals to be included and results in a more accurate representation of the crowd’s psychological factors propagations. Since the psychological dynamics of crowd is naturally unstable, this paper also discusses the application of two nonlinear control approaches to stabilise the crowd to make it calm. Results show that for a crowd of n number of agents, the single-agent controller gives similar performance with the n-agent controller but with much less resources. The simulation results also show that it takes less amount of time to stabilise a crowd when the crowd model includes social interaction weights

Determination of the melting layer from meteorological radar data in Malaysia

A developed algorithm based on the vertical profile of radar reflectivity, has been applied to determine the boundaries of the melting layer and its thickness. The average values of the melting layer heights are compared with ITU-R recommendations and other obtained results in tropical regions at 500m resolution range. The results obtained showed lower values for heights of the melting layer