Scattering regimes for underwater optical wireless communications using Monte Carlo simulation

Optical wireless communications has shown tremendous potential for underwater applications as it can provide higher bandwidth and better security compared to acoustic technologies. In this paper,  an investigation on scattering regimes for underwater links using Monte Carlo simulation has been presented.While the focus of this paper is on diffuse links, the simulation results of collimated links is also provided for comparison purpose. Three types of water namely clear, coastal and turbid water are being used in the simulation. It is shown that the effect of scattering on the path loss cannot be accurately modeled by the existing channel model; ie. Beers-Lambert (BL) law.  It has been shown that  the distance at which the unscattered light drops to zero can be used to estimate the transition point for the scattering regimes in case of diffuse links. The transition point for diffuse links in coastal water and turbid water can be estimated to be around 22 m and 4 m respectively. Further analysis on the scattering order probability at different scattering regimes illustrates how scattering is affected by beam size, water turbidity and distance. From the frequency response plot, it is estimated that the bandwidth of several order of GHz can be achieved when the links are operating in the minimal scattering region and will reduce to several hundreds of MHz when the link is operating in multiple scattering region

A CASE STUDY OF STUDENT PERFORMANCE IN ELECTRIC CIRCUIT 2 SUBJECT

Institution of Higher Learning plays an important role to produce high quality graduates. The most important factor that determines graduates quality shown in their CGPA. In order to maintain high CGPA, students should perform well especially in their examination where it contributes the most in the assessment. Students should mastered basic subject in order to maintain their grades. This survey is to study the reasons for poor performance of the students in Electric Circuit 2 subject. Findings have shown that student’s performance was not only influence by the lecturer but also interrelated to student’s ability and how they see the learning process it either they are a surface or deep learner

Experimental Study of Straight Guiding Structures for Optical Wireless Communications Within a Vehicular Environment

Generous increments in powerful electronic systems and functions have produced significant implications for the vehicular industry, especially in connecting the electronics infrastructure as it is complicated and costly. A limited amount of research has been conducted to investigate proper wireless advancements that might reasonable with the emerging network standard within the context of intravehicular networks. This paper reports an experimental investigation of Optical Wireless Communication (OWC) links within guiding structures for a vehicular environment. The experiment has characterized the infrared transmission characteristics using different types of materials and the influence of the geometry on significant infrared channel parameters. The upper and lower 3-dB frequencies for line of sight (LOS) transmission in the tubes demonstrate that the tubes do not significantly change the frequency response of the transmission but this rather depends on the other channel factors such as materials and geometry

Antioxidant effects of some selected flavonoids: a structure-activity relationship based study

Objective: To investigate the antioxidant and radical scavenging activities of some selected flavonoids with respect to identify key positions responsible for antioxidant effects as well as the effect of derivatisation on the antioxidative effects. Design and method: Antioxidant potential was evaluated using different sets of assays viz., rapid test by dot blot, 1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, ABTS+ radical cation scavenging, ferric reducing antioxidant powder (FRAP) and xanthine oxidase inhibitory (XOI) assays. Results: It was determined that the total number and the configuration of hydroxyl group play an important role in regulating bioactivity of flavonoids in scavenging DPPH radical, ABTS+ radical cation and FRAP assays. Presence of catechol and the absence of C-2-C-3 double bond as well as ketonic group at C-4 reduced the xanthine oxidase inhibitory activity. Methylation and acetylation of hydroxyl groups at particular positions were also found to decrease the in vitro bioactivity of flavonoids. Conclusions: The results of this study will further help to understand the role of flavonoids as natural antioxidants which might facilitate in the development of nutritional products and semi synthetic analogs that retain substantial antioxidant capacity with minimal adverse effects. Keywords: Flavonoids; antioxidant activity; derivatisation, structure activity relationshi

Performance Optimization of Erbium Doped Fiber Amplifier in Wavelength Division Multiplexing System for Long Haul Transmission

This research explores how to optimize the Erbium Doped Fiber Amplifier that being used in Wavelength Division Multiplexing for Long Haul Optical Transmission System. The paper explains the fundamental knowledge, the characteristics of Erbium Doped Fiber Amplifier and the simulation process involved in completing the research. The methods used to achieve the objectives are also clarified throughout the report

THE 'FITTED’ MANAGEMENT FOR HUMAN CAPITAL DEVELOPMENT IN PUBLIC SECTOR

The success of economic and social development depends on the public sector competency, good governance, and functions. However, the reality in most developing countries which embeds a centralized policy in public services, this becomes a barrier for an effective provision of public services towards global competition. This relates closely to people and organization development in public institutions. The purpose of this paper is to review challenges faced by public sector and to seek solutions based on the concept of integration, implementation, and performance measurement of their business. The proposed conceptual framework is Fitted Management, where the exploration of the organization processing capabilities and how to manage it (to be consistent with the globalization). This will be based on the premise of what constitutes a customer value in the public sector by improving the ability of employees and organizations

Factors predicting the outcome of non-operative management of high-grade blunt renal trauma

Objectives: In this retrospective study we reviewed the outcome of non-operative management of high-grade blunt renal injuries (grade III–V) and evaluated the predictive indicators of management failure. Subjects and methods: The data review included the patients’ demographics, the mechanism of trauma and the clinical characteristics, as well as the laboratory and imaging data upon admission and at follow-up. The data of the patients who were successfully managed non-operatively and of those who needed intervention for renal injuries were compared. Results: Two hundred and six patients were enrolled in this study. Grade III, grade IV and grade V renal injuries were found in 39.8%, 44.2% and 16% of the patients, respectively. The overall success rate of non-operative management was 87.9%, including all patients with grade III, 86.8% of patients with grade IV and 60.6% of those with grade V injuries. Multivariate analysis revealed that trauma secondary to motor vehicle accident, hypotension at presentation, associated injuries to other organs, grade V renal injury and computed tomography (CT) imaging features, namely medial renal parenchymal laceration, perirenal hematoma ≥3.5 cm and intravascular extravasation were significant predictors for failure of non-operative management. Conclusion: Our findings suggest that high-grade renal injuries in hemodynamically stable patients can be managed conservatively with a high success rate. Multiple clinical and radiological variables can predict the treatment outcome