Experimental Analysis of Cable Distance Effect on Signal Attenuation in Single and Multimode Fiber Optics

Losses during transmission and high demand of high data rate by the end users have become the biggest challenges facing the telecommunication industries worldwide with Nigeria inclusive. Fiber optic cable as a channel of communication has been adapted worldwide in solving these problems but there is a little limitation in the place of multimode fiber in long distance communication. This paper focuses on the effect of changes in distance on transmitted bandwidth on single mode and multimode fiber. Two cases were considered during this research; (a) with optical amplifier placed in between multimode fiber and (b) without optical amplifier in between multimode fiber. Readings were taken at various distances when specific bandwidth ranging from 50Mbps to 500Mbps was transmitted from the base station to the various distances and it was observed that there was no significant changes in bandwidth received at specified distances (100, 200, 300, 400, 500 etc) m when using single mode fiber, there was a drastic reduction in bandwidth when it get to a distance of 300m when using multimode. When optical amplifier was placed in between the multimode fiber at some selected distances after 400m from the transmitting BTS, it was noticed that the drastic reduction in transmitted bandwidth was almost eliminated, thereby proven that multimode fiber can be use in long distance communication provided optical amplifiers are incorporated in between the distance to bust the signal strength

Improved Alamouti STBC Multi-Antenna System using Hadamard Matrices

YesTo achieve multiple input multiple output (MIMO) in wireless communication, the orthogonal space-time block coding (OSTBC) is evaluated next. At first, the OSTBC design is extended to include Hadamard matrix, referred to in this work, as traditional Hadamard OSTBC. Next, the Hadamard matrix is imposed on the conventional OSTBC, which is referred to, in this work as, Alamouti-Hadamard STBC. Both the traditional Hadamard OSTBC and the conventional STBC are compared with the Alamouti-Hadamard STBC. It will be shown that imposing the Hadamard conditions over the conventional OSTBC, the performance of the OSTBC 2-transmit antenna scheme can be significantly improved in terms of BER performance. All propositions are well supported with analytical derivations

Financing and Supply Chain Operations Resilience and Juxtaposing: The Role of Finance in Improving the Supply Chain in the COVID-19 Pandemic Environment

Amidst the renewed quest for supply chain resiliency, finance outgrows its traditional role in B2B; instead, finance position itself to become a more integrated partner in supply chain management activities. Areas such as global trade management and supply chain risk management are fluid areas for finance to flourish, coupled with increasing demands for finance to take a more active role in supply chain management. The global supply chain has experienced several disruptions, such as the COVID-19 pandemic, extreme climate change-induced events, natural disasters, conflict, financial crises, recessions, shortages of raw materials for manufacturing, and macroeconomic imbalances; however, futuristic disruptions are already projected by several stakeholders in the logistics and transport sector. Hence, companies must concentrate on building their resilience to all manner of supply chain disruptions. The initial motive of firm management to increase leverage and engage in financial goods is diminished when the economic dilemma of supply chain value is resolved; by so doing, the internal financial situations could facilitate the advancement of enterprise value. Keywords: supply chain, financial service innovations, distribution dimension, COVID-19 DOI: 10.7176/EJBM/15-7-01 Publication date: April 30th 202

Effect of laser power on the microstructure and microhardness property of hybrid fabricated Ti6Al4V based metal matrix composite

Abstract: Several surface coatings on Ti-6Al-4V alloy using laser treatment technique have been investigated in this paper. A hybrid Ti-6Al-4V based metal matrix composites system was also successfully fabricated. This was possible using three hoper system which contained 3.8 vol. % of Ti-6Al-4V and a small amount 0.1 B4C and 0.1 BN respectively. Two different laser powers “2000 W and 1400 W with scanning speed of 1.0 were employed. The idea of these powder coatings and reason for investigating the different Laser power is to evaluate the influence of laser power on the surface morphology and hardness property of Ti-6Al-4V/B4C/BN alloy systems. The hardness result of experimental showed a general improvement. The hardness revealed that the Ti-6Al- 4V/B4C/BN system fabricated at 2000W showed a hardness improvement as high as 640.4 HVO.5 compared to the as receive Ti-6Al-4V substrate Hardness value of about 357.3 HVO.5 and that of 1400W recorded a hardness value of 886 HVO.5. The percentage increase from the as received Ti-6Al-4V alloy was 147.9% and 79.2% respectively. Problems to be solved and the prospective application of laser modification of the hybrid titanium alloy formed were also highlighted

Novel Fractional Wavelet Transform with Closed-Form Expression

yesA new wavelet transform (WT) is introduced based on the fractional properties of the traditional Fourier transform. The new wavelet follows from the fractional Fourier order which uniquely identifies the representation of an input function in a fractional domain. It exploits the combined advantages of WT and fractional Fourier transform (FrFT). The transform permits the identification of a transformed function based on the fractional rotation in time-frequency plane. The fractional rotation is then used to identify individual fractional daughter wavelets. This study is, for convenience, limited to one-dimension. Approach for discussing two or more dimensions is shown

On the application of raised-cosine wavelets for multicarrier systems design

YesNew orthogonal wavelet transforms can be designed by changing the wavelet basis functions or by constructing new low-pass filters (LPF). One family of wavelet may appeal, in use, to a particular application than another. In this study, the wavelet transform based on raisedcosine spectrum is used as an independent orthogonal wavelet to study multicarrier modulation behaviour over multipath channel environment. Then, the raised-cosine wavelet is compared with other well-known orthogonal wavelets that are used, also, to build multicarrier modulation systems. Traditional orthogonal wavelets do not have side-lobes, while the raised-cosine wavelets have lots of side-lobes; these characteristics influence the wavelet behaviour. It will be shown that the raised-cosine wavelet transform, as an orthogonal wavelet, does not support the design of multicarrier application well like the existing well-known orthogonal wavelets

The Impact of Text Message Slang (Tms) or Chartroom Slang on Students Academic Performance

Abstract The research is on the impact of text slang or chartroom slang on students' academic performance. It is an unstructured language that violates the standard rules of the English language. So the research is necessitated by the fact that most students in recent times have resorted to the use of text message slang or chartroom slang in their class work as well as in their examinations. This is not a good phenomenon as they eventually are the same people that will end up teaching the next generation of Nigerians. If the use of text message slang is not currently checked, it will completely erode proper use of the English language. The research therefore seeks the effects of such improper language can have on students academic performance. Descriptive research methodology was adopted and in order to elicit information from the respondents, questionnaire was constructed and distributed on hand-to-hand basis to the students immediately after their classes. This was done to ensure effective retrieval of the instrument. A total of three hundred and thirty (330) questionnaires were administered and three hundred and twenty four (324) were found usable as only this number was duly filled and returned

A Multi-Antenna Design Scheme based on Hadamard Matrices for Wireless Communications.

YesA quasi-orthogonal space time block coding (QO-STBC) scheme that exploits Hadamard matrix properties is studied and evaluated. At first, an analytical solution is derived as an extension of some earlier proposed QO-STBC scheme based on Hadamard matrices, called diagonalized Hadamard space-time block coding (DHSBTC). It explores the ability of Hadamard matrices that can translate into amplitude gains for a multi-antenna system, such as the QO-STBC system, to eliminate some off-diagonal (interference) terms that limit the system performance towards full diversity. This property is used in diagonalizing the decoding matrix of the QOSTBC system without such interfering elements. Results obtained quite agree with the analytical solution and also reflect the full diversity advantage of the proposed QO-STBC system design scheme. Secondly, the study is extended over an interference-free QO-STBC multi-antenna scheme, which does not include the interfering terms in the decoding matrix. Then, following the Hadamard matrix property advantages, the gain obtained (for example, in 4x1 QO-STBC scheme) in this study showed 4-times louder amplitude (gain) than the interference-free QOSTBC and much louder than earlier DHSTBC for which the new approach is compared with

Performance Evaluation of Raised-Cosine Wavelet for Multicarrier Applications

YesWavelets are alternative building kernels of the multicarrier systems, such as the orthogonal frequency division multiplexing (OFDM). The wavelets can be designed by changing the parent basis functions or constructing new filters. Some two new wavelets are considered for multicarrier design; one is designed using raised-cosine functions while the other was constructed using ideal filters. The spectrums of raised cosine wavelet filters are controlled by a roll-off factor which leads to many distorting sidelobes. The second family of wavelet, which the raised-cosine wavelet is compared to, have no distorting sidelobes. It will be shown that raised-cosine wavelets are less suitable for multicarrier design in multicarrier environment, in terms of BER when compared to the wavelet constructed from the ideal filter

Effect of rapid cooling of high temperature laser fabricated Ti/B4C/BN coating on Ti-6AL-4V alloy

Abstract: A hybrid Ti-6Al-4V based metal matrix composites characterized of martensitic structure was formed using three hoper system. Different volume percentages used were as follows: 3.0 vol. % of Ti-6Al-4V, 3.2 vol. % of Ti-6Al-4V and 3.4 vol. % of Ti-6Al-4V respectively while an equal amount of BN and B4C mixed with the Ti-6Al-4V powder particle was fed through the hoper systems at a constant laser power 2000 W and scanning speed of 1.0 m/s. The influence of rapid cooling and varied powder particle at constant coating temperature on the surface morphology and hardness property of Ti-6Al- 4V/B4C/BN alloy systems was however investigated. The hardness result of experimental showed a general improvement. Further result showed that the Ti-6Al- 4V/B4C/BN system fabricated at 3.0 Ti Vol. percent had a hardness improvement as high as 986.9 HVO.5 compared to the as receive Ti-6Al-4V substrate Hardness value of about 357.3 HVO.5. 3.2 Ti Vol. percent systems recorded a hardness value of 723.4 HVO.5 and 3.2 Ti Vol. percent system recorded a hardness value of 609.6 HVO.5. Optical microscope (OM) Scanning electron microscope (SEM) was also carried out for microstructural evaluation and Energy Dispersive Spectroscopy (EDS) to confirm the elemental composition of coating when necessary