Mitigating Turbulence-Induced Fading in Coherent FSO Links: An Adaptive Space-Time Code Approach

Free space optical communication systems have witnessed a significant rise in attention over the last half a decade owing largely to their enormous bandwidth and relative ease of deployment. Generally, free space optical communication systems differ in their detection mechanism as various detection mechanisms are being reported, including intensity modulation/direct detection FSO, differential FSO and coherent FSO. In this chapter, we explore the prospect of obtaining an optimally performing FSO system by harnessing the cutting-edge features of coherent FSO systems and the coding gain and diversity advantage offered by a four-state space-time trellis code (STTC) in order to combat turbulence-induced fading which has thus far beleaguered the performance of FSO systems. The initial outcomes of this technique are promising as a model for various visible light communication applications

Characterisation of Signal Amplitude-Frequency for Indoor Power Line Communication Channel in the 1 — 30 MHz Broadband Frequencies

The transmission of data signals over power lines is a very promising technique for delivering indoor broadband communication services. However, since power grids were originally designed for high-voltage low-frequency signal transmission, there is a frequency mismatch between the power grid and high-frequency data signals. This mismatch poses a challenge to deploying power lines as a communication channel. Although, studies and researches conducted in several countries have made transmission of data over power lines possible, the behaviour and properties of the power grid cannot be generalised. Hence, the need for in-depth experiment and measurement on the suitability and capability of the Nigerian power grid for data transmission is crucial for proper characterising and modelling of the power line communication (PLC) channel. In this paper, we present experimental measurements and results of the effects of frequency variations on the attenuation experienced by broadband high-speed data signals transmitted over the Nigerian indoor power line network

SEMIOTICS AND MEANING IN ARCHITECTURE: A STUDY OF CULTURAL SPACES AND BUILT-FORMS OF SOUTHWEST NIGERIA

Architect re is a sym olic channel of comm nicating eo les’ c lt re If well achieved architecture will be meaningful, easily understood, appreciated and can be applied to ensure a sustainable environment. Semiotics, which refers to the symbolic identities and meanings in cultural built-forms and spaces have been poorly understood and appreciated in Southwest Nigeria. As a study of sign systems, semiotics through our social and cultural background identifies culture as communication, with architecture as a relevant object of analysis. General semiotics studies have been undertaken in such areas as aesthetics, semantics and space syntax as a symbolic sign language. However, the dearth of studies on issues relating to signs, symbols and meanings of spaces and built-forms among the Yoruba people of Southwest Nigeria has necessitated this research. Hence, the research examined symbolic cultural values of architectural spaces and built-forms of Southwest Nigeria. The concept of architectural semiotics was used to investigate symbols and meanings associated with cultural built-forms and spaces in Southwest Nigeria. The study is descriptive and interpretive and adopted the ethnographic approach in the context of a multi-case study strategy. The cultural metaphorical framework of evaluating a house in the context of the human anatomy and the archaeological method of finding new sustainable traits from known cultural forms were used. Relevant traditional-Vernacular built forms were selected through an initial reconnaissance survey and sym olic or a lang age common statements that hel ed etter inter retation of sam les’ characteristics. A systematic review of the common statements and other data obtained from oral and written literature. Bungalows, storey buildings (Indigenous or with western and Islamic influences), palaces, relics, groves, rocks and other natural cultural spaces were sampled. Oral tradition made up for the absence of written texts and monumental built-forms to relive the pastsing the o thwest eo les’ M t al Context al Beliefs (M C B) emiotics’ “Glo al emantics Field (G F) enotation and Connotation and other theories were also applied. At least eight housing typologies were discovered, with commonalities of basic rectangular shape, courtyards, large family lobby (oruwa) are highlighted. Some potsherd pavements and groves among other relics were identified and non-preservation observed. Findings showed levels of meanings and multi-function in building components like the àjà (roof lofts), and òpó (columns). A ’ (plinthed upstand sitting/slee ing s aces) were in front of the first wife’s rooms. Burial spaces inside the house in the study area depicting the communion of the living and the dead were also discovered in some Orthodox Church buildings. Built-forms and spaces terms inter retation revealed in a statement like: i b r wo b’i o ’ (a low house like a ra it’s hole that entrants end to enter) was deli erate in shrine designs. The traditional anthropometrics method was learnt. Unifying design qualities of cultural built-forms and spaces were confirmed to inspire concepts and practice for a sustainable environment. In conclusion, semiotic studies on cultural built-forms for their interpretation and preservation should be continuous and should be encouraged in other geo-political zones, with lessons there-from being made applicable to enhance sustainable built environments

An Integrated Approach to Automated Control for Air-Conditioned Home Apartments using Wireless Sensor Network

An Integrated Approach to Automated Control for Air-Conditioned Home Apartments using Wireless Sensor Network Moses O. Onibonoje*, Oladipo Folorunso, Adedayo Ajibade and Kehinde A. Adeniji Department of Electronic/Electrical and Computer Engineering, Afe Babalola University, Ado Ekiti, Nigeria; [email protected], [email protected], [email protected], [email protected] Abstract Objectives : Home automation is achievable with an integrated approach using Wireless Sensor Networks (WSNs). This paper presents the implementation of such integrated approach to automating the air-conditioning of various apart