Statistical Model for Polarization Mode Dispersion in Single Mode Fibers

As the bit rate of fiber optic transmission systems is increased to more than , the system will suffer from an important random phenomena, which is called polarization mode dispersion. This phenomenon contributes effectively to: increasing pulse width, power decreasing, time jittering, and shape distortion. The time jittering means that the pulse center will shift to left or right. So that, time jittering leads to interference between neighboring pulses. On the other hand, increasing bit period will prevent the possibility of sending high rates. In this paper, an accurate mathematical analysis to increase the rates of transmission, which contain all physical random variables that contribute to determine the transmission rates, is presented. Thereafter, new mathematical expressions for: pulse power, peak power, time jittering, pulse width, and power penalty are derived. On the basis of these formulas, one can choose a certain operating values to reduce or prevent the effects of polarization mode dispersion

Fundamental Study On Thermal Surface Analysis Of Late Modern Styles’ Apartments With Case Studies In Malaysia

This study discusses a comparative analysis of the thermal surface temperature on high-rise apartments designed with late modern styles in Malaysia. In Malaysia, apartments are divided to two categories namely midrise and highrise apartments. Highrise apartments are the residential buildings higher than five stories equipped with elevator whereas midrise apartments have no elevators with 3 to 5 stories’ height. The results of this study will provide a thermal surface data of the apartment facades. The data analyse the level of sustainability awareness of the architectural styles on facade design to the tropical context. This thermal surface analysis will figure the design awareness of the architects who design the buildings in complying with their understanding to the climatic factors. Late modern design styles have a complex geometric design with ranging from simple to complex roof structures which have an emphasis on abstract geometric form in building design. In this study, two late modern design apartments are selected as the case studies. The location of these apartments is in Putrajaya, the latest new town built as an administrative city of Malaysia. The thermal surface data will be detected by a thermal device named Fluke Ti20 Infrared Camera. This camera will capture thermal images of the apartment facades. The analysis indicates that both apartments have relatively good performance of the facade design with thermal surface data. In conclusion, by designing apartment with shading design, it guides with passive design elements which must be integrated in building design in tropical climate

Design and analysis of routing protocol for cognitive radio ad hoc networks in Heterogeneous Environment

Multi-hop routing protocol in cognitive radio mobile ad hoc networks (CRMANETs) is a critical issue. Furthermore, the routing metric used in multi-hop CRMANETs should reflect the bands availability, the links quality, the PU activities and quality of service (QoS) requirements of SUs. For the best of our knowledge, many of researchers investigated the performance of the different routing protocols in a homogeneous environment only. In this paper, we propose a heterogeneous cognitive radio routing protocol (HCR) operates in heterogeneous environment (i.e. the route from source to destination utilize the licensed and unlicensed spectrum bands). The proposed routing protocol is carefully developed to make a tradeoff between the channel diversity of the routing path along with the CRMANETs throughput. Using simulations, we discuss the performance of the proposed HCR routing protocol and compare it with the AODV routing protocol using a discrete-event simulation which we developed using JAVA platform

Anti-inflammatory new coumarin from the Ammi majus L

Investigation of the aerial parts of the Egyptian medicinal plant Ammi majus L. led to isolation of new coumarin, 6-hydroxy-7-methoxy-4 methyl coumarin (2) and 6-hydroxy-7-methoxy coumarin (3); this is the first time they have been isolated from this plant. The structures of the compounds (2 &3) were elucidated by spectroscopic data interpretation and showed anti-inflammatory and anti-viral activity

Geochemistry of the Neoproterozoic Wadi Ghadir and Fawakhir ophiolites and associated rocks, Central Eastern Desert, Egypt: Implication for geodynamic setting

The geochemistry of the ophiolitic complexes and younger late orogenic sedimentary rocks in the Wadi Ghadir and Fawakhir areas has been studied to constrain the tectonic evolution of the Central Eastern Desert. The Wadi Ghadir ophiolite is composed of gabbros and pillow lavas that are intruded by many dike swarms and all of them display subduction zone chemical signatures. The ophiolitic rocks and the surrounding melange were intruded by younger dikes with Andean-type geochemical signature. The Wadi Ghadir ophiolite has chemical similarities to the oceanic crust formed in back-arc basins. The location of the Wadi Ghadir ophiolite to the northeast of the Nugrus volcanic arc and the appearance of forearc amphibolites to the southwest of the Nugrus arc rocks indicates a NE-dipping subduction zone. The accretion of this arcback-arc system onto the passive margin to the west resulted in the reversal in the subduction direction and the establishment of a new Andean-type continental margin. The Fawakhir ophiolite comprises serpentinized ultramafic rocks, gabbros, sheeted dike complexes, and pillow lavas. The geochemical characteristics of the Fawakhir ophiolite are comparable to the forearc oceanic crust developed in the Izu-Bonin-Mariana arc system. However, pillow lavas preserved in the melange to the west have a geochemical signature similar to that of a modern back-arc oceanic crust which suggests formation of an intra-oceanic arc system above an east-dipping subduction zone. As in Wadi Ghadir, the Fawakhir ophiolite is intruded by later calc-alkaline dikes possessing geochemical signatures similar to rocks that occur at modern active continental margins. The initiation of the Andean-type calc-alkaline magmatism may indicate a reversal in subduction polarity from east-dipping during arc accretion to west-dipping and formation of an active continental margin. The Umm Hassa Greywacke member is the top unit of the Hammamat Group which is late orogenic molasse-type sedimentary rocks. Continental arc volcanic rocks and oceanic island arc-ophiolitic sources are the main contributors to the sediments of the Urn Hassa greywackes. Considering the geodynamic evolution of the Central Eastern Desert, the Um Hassa greywackes were deposited in retroarc foreland basin behind the continental arcs developed over a west-dipping subduction zone

Modified Unequally Spaced Channels Wavelength Division Multiplexing System

The channels contributed in creating new pulse during the four-wave mixing (FWM) process are a subject of two features: the first is the fact that all channels are not working with probability %100 , but with p probability. Second, the bits transmitted are not all "1". Therefore, the equation of power generated using these features should be corrected. On the other hand, the use of equally spaced channels wavelength divisionmultiplexing (ESC WDM) system cause an increase in the number of new components generated that interfere with the active channels and increase the bit error rate. In order to reduce these interferences, we have provided an unequally spaced channels wavelength division-multiplexing (USC WDM) system composed of several sets. Each set consists of only four channels, which locations have been selected to cause no interferences between them. Neighboring sets are separated by a frequency spacing which should be large enough to reduce the interferences between the sets, andsmall enough to increase the total number of channels of the system

Modified Unequally Spaced Channels Wavelength Division Multiplexing System

The channels contributed in creating new pulse during the four-wave mixing (FWM) process are a subject of two features: the first is the fact that all channels are not working with probability %100 , but with p probability. Second, the bits transmitted are not all "1". Therefore, the equation of power generated using these features should be corrected. On the other hand, the use of equally spaced channels wavelength divisionmultiplexing (ESC WDM) system cause an increase in the number of new components generated that interfere with the active channels and increase the bit error rate. In order to reduce these interferences, we have provided an unequally spaced channels wavelength division-multiplexing (USC WDM) system composed of several sets. Each set consists of only four channels, which locations have been selected to cause no interferences between them. Neighboring sets are separated by a frequency spacing which should be large enough to reduce the interferences between the sets, andsmall enough to increase the total number of channels of the system

The Impact of Corporate Social and Environmental Practices on the Cost of Equity Capital:UK Evidence

PurposeThere has been an ongoing call from various groups of stakeholders for social and environmental practices to be integrated into companies’ operations. A number of companies have responded by engaging in socially and environmentally responsible activities, while others choose not to participate in these activities, which incur additional costs. The absence of consensus regarding the economic implications of social and environmental practices provides the impetus for this paper. This study aims to examine the association between corporate social and environmental practices (CSEP) and the cost of equity capital measured by four ex ante measures using a sample of UK listed companies.Design/methodology/approachFirst, we undertake a review of the extant literature on CSEP. Second, using a sample of 236 companies surveyed in “Britain’s most admired companies” in terms of “community and environmental responsibility” during the period 2010-2014, we estimate four implied a cost of equity capital proxies. The relationship between a companies’ cost of equity capital and its CSEP is then calculated.FindingsThe authors find evidence that companies with higher levels of CSEP have a lower cost of equity capital. This finding determines the significant role played by CSEP in helping users to make useful decisions. Also, it supports arguments that firms with socially responsible practices have lower risk and higher valuation.Practical implicationsThe finding encourages companies to be more socially and environmentally responsible. Furthermore, it provides up-to-date evidence of the economic consequences of CSEP. The results should, therefore, be of interest to managers, regulators and standard-setters charged with developing regulations to control CSEP, as these practices are still undertaken on a voluntary basis by companies.Originality/valueTo the best of the authors’ knowledge, this is the first study to investigate the association between CSEP of British companies and their cost of equity capital. The study complements Ghoul et al. (2011), who examine the relationship between CSR and the cost of equity capital of the US sample. The authors extend Ghoul et al. (2011) by using a sample of the UK market after applying International Financial Reporting Standards.</p