scholarly journals Signal Classification Algorithms over Time Selective Channels

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1714
Author(s):  
Mohamed Marey ◽  
Hala Mostafa
Keyword(s):  
Block Code ◽  
Classification Problem ◽  
Classification Performance ◽  
Signal Classification ◽  
Final Decision ◽  
Time Block ◽  
Channel Response ◽  
Over Time ◽  
Parallel Fashion

In this work, we propose a general framework to design a signal classification algorithm over time selective channels for wireless communications applications. We derive an upper bound on the maximum number of observation samples over which the channel response is an essential invariant. The proposed framework relies on dividing the received signal into blocks, and each of them has a length less than the mentioned bound. Then, these blocks are fed into a number of classifiers in a parallel fashion. A final decision is made through a well-designed combiner and detector. As a case study, we employ the proposed framework on a space-time block-code classification problem by developing two combiners and detectors. Monte Carlo simulations show that the proposed framework is capable of achieving excellent classification performance over time selective channels compared to the conventional algorithms.

scholarly journals Feature extraction by grammatical evolution for one-class time series classification

2021 ◽  
Author(s):  
Stefano Mauceri ◽  
James Sweeney ◽  
Miguel Nicolau ◽  
James McDermott
Keyword(s):  
Time Series ◽  
Classification Problem ◽  
Classification Performance ◽  
Grammatical Evolution ◽  
Data Driven ◽  
Time Series Classification ◽  
Class Time ◽  
Feature Based ◽  
Representation Of Time

AbstractWhen dealing with a new time series classification problem, modellers do not know in advance which features could enable the best classification performance. We propose an evolutionary algorithm based on grammatical evolution to attain a data-driven feature-based representation of time series with minimal human intervention. The proposed algorithm can select both the features to extract and the sub-sequences from which to extract them. These choices not only impact classification performance but also allow understanding of the problem at hand. The algorithm is tested on 30 problems outperforming several benchmarks. Finally, in a case study related to subject authentication, we show how features learned for a given subject are able to generalise to subjects unseen during the extraction phase.

When Culturally Significant Songs are Decontextualised: The Initiation Song Somagwaza, A Case Study

2018 ◽  
Vol 28 (2) ◽  
Author(s):  
T Dowling ◽  
Somikazi Deyi ◽  
Anele Gobodwana
Keyword(s):  
Qualitative Research ◽  
Comparative Method ◽  
Popular Song ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Ritual Music ◽  
Constant Comparative Method ◽  
Small Focus ◽  
Over Time

While there have been a number of studies on the decontextualisation and secularisation of traditional ritual music in America, Taiwan and other parts of the globe, very little has been written on the processes and transformations that South Africa’s indigenous ceremonial songs go through over time. This study was prompted by the authors’ interest in, and engagement with the Xhosa initiation song Somagwaza, which has been re-imagined as a popular song, but has also purportedly found its way into other religious spaces. In this article, we attempted to investigate the extent to which the song Somagwaza is still associated with the Xhosa initiation ritual and to analyse evidence of it being decontextualised and secularised in contemporary South Africa. Our methodology included an examination of the various academic treatments of the song, an analysis of the lyrics of a popular song, bearing the same name, holding small focus group discussions, and distributing questionnaires to speakers of isiXhosa on the topic of the song. The data gathered were analysed using the constant comparative method of analysing qualitative research.

Thinning in mature eastern white pine: 43-year case study

2002 ◽  
Vol 78 (4) ◽  
pp. 539-549 ◽  
Author(s):  
Paul D Anderson ◽  
John C Zasada ◽  
Glen W Erickson ◽  
Zigmond A Zasada
Keyword(s):  
Genetic Diversity ◽  
Dna Analysis ◽  
Large Diameter ◽  
White Pine ◽  
Thinning Intensity ◽  
Pine Regeneration ◽  
Volume Production ◽  
Pine Stands ◽  
Over Time

A white pine (Pinus strobus L.) stand at the western margin of the species range, approximately 125 years of age at present, was thinned in 1953 from 33.5 m2 ha-1 to target residual basal areas of 18.4, 23.0, 27.5, and 32.1 m2 ha-1 . Repeated measurement over the following 43-years indicated that the greatest total volume production and the greatest number of large diameter trees occurred in the unit of highest residual density. Over time, the distribution of stems was predominantly random although mortality between 1979 and 1996 resulted in a tendency for clumping in the 23.0 and 27.5 m2 ha-1 treatments. DNA analysis indicated that thinning intensity had little effect on the genetic diversity of residual white pine. This study suggests that mature white pine stands in northern Minnesota may be managed at relatively high densities without loss of productivity. However, regardless of overstory density, there was little or no white pine regeneration occurring in this stand. Key words: thinning, growth, genetic diversity, molecular markers, spatial pattern, regeneration

scholarly journals Can politically oriented interventions in built heritage contribute to its authenticity? Erbil Citadel’s Babylonian Gate as a case study

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed Awadh Jasim ◽  
Laura Hanks ◽  
Katharina Borsi
Keyword(s):  
Cultural Value ◽  
Cultural Issues ◽  
Built Heritage ◽  
Projection Screen ◽  
Conflicting Demands ◽  
Existential Issue ◽  
Over Time

AbstractToday, the concept of built heritage authenticity is a projection screen for conflicting demands and thus a ‘contested field’. Short-sighted readings started to drag the concept behind different ill-considered treatises, in which some heritage aspects loosely outweighed other aspects. Archaeological perspectives that tend to freeze heritage structures in time, such as those that are privileged upon other contemporary socio-cultural issues, while political takes also overshadowed other epistemological prospects, and vice versa. Repercussions have made inclusion of what is regarded as ‘inevitable changes’ within the built context problematic as to the re-interpretation and thus assessment of its authenticity. Despite their possible momentary threat to the latter, these changes may add to the cultural value of the context over time, granting new potential that may instead boost its authenticity. This paper investigates the potential continuity of Erbil Citadel’s Babylonian Gate as an inevitable change within the site’s built context by studying the Gate’s controversial political impacts on the context’s authenticity. This study affirms that authenticity is a transcendental value of an open-ended progressive nature, which cannot be reduced to a specific period or properties within the historical chronology of built heritage. Hence, authenticity should be approached as a meaningful existential issue, while revelation of its essence and thus its dimension entails precise scrutiny of both the tangibles and intangibles of the context. However, to be part of its authenticity, any change in the context should be adaptable and possibly incorporated as a new value within its cultural strata, thus enabling progressive support for site authenticity.

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