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Research Article
Performance Evaluation of Different Threshold Estimation Rules in Denoising EEG Singal with Hamming Window-Based Shrinkage Technique
Issue:
Volume 10, Issue 4, December 2025
Pages:
168-174
Received:
12 August 2025
Accepted:
13 September 2025
Published:
10 October 2025
Abstract: Signal denoising is an integral part of contaminated signal processing to obtain the signal of interest. In this research, a developed system for reliable removal of powerline interference from Electroencephalographic (EEG) signal based on descrete wavelet transform technique is designed which includes soft thresholding –based shrinkage function called hamming window (Ham-WSST). A practical EEG signal was acquired by measurement from Federal Medical Centre, Owerri and contaminated with powerline noise of 50Hz. This was sampled at a frequency of 1000Hz. Due to the new shrinkage function, decomposition level of 7 and daubechies 7 (db7) mother wavelet, the denoising of the powerline noise was extensively performed in combination with Sqtwolog, Rigrsure, Heursure and Minimaxi rule. The outcome results for the four threshold rules of the system were evaluated and compared using power spectral density (PSD), signal to noise (SNR), mean square error (MSE) and maximum absolute error (MAE) estimation functions. The power spectral density result established on the optimum decomposition level of 7 at 0.1 radian normalised frequency was 35.89 dB for Sqtwolog rule, 37.68dB for Rigrsure, 37.68dB for Heursure and for Minimaxi value is 36.52dB. For signal to noise ratio (SNR) the value for Sqwolog is 42.26 dB, Rigrsure is 38.68dB, Heursure is 38.68dB and Minimaxi is 40.55dB. The estimation values for mean square error (MSE) and maximum absolute error (MAE) for Sqtwolog rule, Rigrsure rule, Heursure rule and Minimaxi rule in this order is giving as 0.00147, 0.0046, 0.00492, and 0.00206; 0.1147, 0.1245, 0.1245 and 0.1158. Less PSD value means more noise attenuation at the considered frequency instant, higher value for SNR indicate more signal of interest than noise while lower values of MSE and MAE indicate less error. The research further shows that the window thresholding shrinkage function based on the Hamming window with the Sqtwolog estimation rule is more effective at denoising contaminated EEG signals with powerline noise..
Abstract: Signal denoising is an integral part of contaminated signal processing to obtain the signal of interest. In this research, a developed system for reliable removal of powerline interference from Electroencephalographic (EEG) signal based on descrete wavelet transform technique is designed which includes soft thresholding –based shrinkage function ca...
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Research Article
Minimization of Fuel Consumption in Four Stroke Six Cylinder Engines Using Idle Speed Control
Chinonso Francis Nkeoma Ubbaonu*,
Damian Obioma Dike,
Raymond O. Opara,
Chiedozie Francis Paulinus-Nwamuo,
Ernest Ezugwu
Issue:
Volume 10, Issue 4, December 2025
Pages:
175-184
Received:
10 April 2017
Accepted:
14 June 2017
Published:
14 October 2025
DOI:
10.11648/j.ajset.20251004.12
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Abstract: In a distressed economy with increasing cost of fuel, it is necessary to achieve control of automobile engine over transient behavior and meet performance objectives within the planned life of the vehicle. In this paper the objective is to design a model predictive controller (MPC) that will minimize fuel consumption in a four stroke cylinder engine using idle speed control. Engine speed is most often affected by unexpected disturbances, and the higher the engine speed at idle the higher the consumption of fuel. Non linear dynamic equations of an idle speed engine were obtained and later transformed to equivalent linear equation by linearization method. The designed MPC was integrated with a linearized equation of the plant. The MPC approach was used to forecast and control the four stroke six cylinder engine model in the presence of unexpected disturbance to achieve the desired objective. Simulations were performed in Matlab/Simulink and the results obtained showed that at different instances when disturbances entered the system, with MPC controller in the loop, the instability introduced by the disturbance was eliminated and the referenced idle speed tracked. There by maintaining the engine idle speed at 600 RPM.
Abstract: In a distressed economy with increasing cost of fuel, it is necessary to achieve control of automobile engine over transient behavior and meet performance objectives within the planned life of the vehicle. In this paper the objective is to design a model predictive controller (MPC) that will minimize fuel consumption in a four stroke cylinder engin...
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Research Article
Crypto-Assets and Property Law: Emerging Challenges in International Trade and Investment
Robert Walters*
,
Bruno Zeller,
Mirella Atherton
Issue:
Volume 10, Issue 4, December 2025
Pages:
185-195
Received:
19 August 2025
Accepted:
10 September 2025
Published:
22 October 2025
DOI:
10.11648/j.ajset.20251004.13
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Abstract: The digitalization of finance is transforming at a rapid rate worldwide. Digital assets and in turn cryptocurrencies continue to attract attention in international trade and investment. They are being used in cross border transnational transactions. While today they are not generally considered legal tender, there has been a slow shift to classifying them as a form of asset, and in turn property. While not overly stated, this area of the law is evolving rapidly, and to date, as a digital asset, cryptocurrencies are also emerging as a form of fund or investment. This is because they are being used as a mechanism for payments. This article seeks to determine whether digital assets and cryptocurrencies fall within the classification of property. The current approach to their classification under the law is fragmented. A common theme emerging is how nation states will apply this financial product to existing law and where necessary categorize them as property. This article also examines a selected number of trade agreements to confirm or otherwise the reference and classification of these asset classes. It concludes by examining selected treaties and determining that the classification of a cryptocurrency as they relate to property will be influenced by a number of different factors. The also article confirms that crypto assets are property, and it has been generally left to the judiciary to make this determination. Recently, nation states have begun to confirm the position of the local and national judiciary’s and legislate that these forms of assets are property.
Abstract: The digitalization of finance is transforming at a rapid rate worldwide. Digital assets and in turn cryptocurrencies continue to attract attention in international trade and investment. They are being used in cross border transnational transactions. While today they are not generally considered legal tender, there has been a slow shift to classifyi...
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Research Article
Solar Drying Techniques as Sustainable Alternatives for Thermal Treatment of Agro-Industrial Waste in Sierra Leone: A Case Study at Eastern Technical University Carpentry Workshop
Ibrahim Massaquoi*
Issue:
Volume 10, Issue 4, December 2025
Pages:
196-202
Received:
14 September 2025
Accepted:
25 September 2025
Published:
27 October 2025
DOI:
10.11648/j.ajset.20251004.14
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Abstract: Background: The increasing environmental concerns and the need for sustainable waste management practices have driven research into alternative thermal treatment methods for agro-industrial waste. Solar drying presents a promising, eco-friendly solution, particularly in regions like Sierra Leone, where abundant sunlight can be harnessed. This case study explores the application of solar drying techniques as sustainable alternatives for thermal treatment of agro-industrial waste at the Eastern Technical University Carpentry Workshop. Methodology: The study employed a comparative experimental design, assessing the efficiency and effectiveness of solar drying against conventional thermal methods. Agro-industrial waste samples, including wood shavings and sawdust, were subjected to solar drying in specially designed solar dryers and traditional heaters. Parameters such as moisture reduction rate, drying time, energy consumption, and waste quality post-drying were measured. Data collection involved temperature monitoring, weight measurements, and qualitative assessments of dried waste. Results: Results demonstrated that solar drying significantly reduced moisture content comparable to conventional methods, with an average drying time of 48 hours versus 24 hours for thermal treatment. Notably, solar drying consumed no external fuel energy, making it more cost-effective and environmentally friendly. The dried waste maintained its structural integrity and suitability for reuse in carpentry processes. Additionally, the solar drying method produced minimal emissions, aligning with sustainability goals. Conclusion: Solar drying techniques offer a viable and sustainable alternative for thermal treatment of agro-industrial waste within the context of Sierra Leone. The method's low operational costs, environmental benefits, and preservation of waste quality suggest its potential for broader adoption in agro-industrial settings, contributing to waste valorization and sustainable development efforts. Future research should focus on optimizing solar dryer designs and scaling up to industrial levels to maximize impact.
Abstract: Background: The increasing environmental concerns and the need for sustainable waste management practices have driven research into alternative thermal treatment methods for agro-industrial waste. Solar drying presents a promising, eco-friendly solution, particularly in regions like Sierra Leone, where abundant sunlight can be harnessed. This case ...
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