39 research outputs found

    Optimization of depth-based routing for underwater wireless sensor networks through intelligent assignment of initial energy

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    Underwater Wireless Sensor Networks (UWSNs) are extensively used to explore the diverse marine environment. Energy efficiency is one of the main concerns regarding performance of UWSNs. In a cooperative wireless sensor network, nodes with no energy are known as coverage holes. These coverage holes are created due to non-uniform energy utilization by the sensor nodes in the network. These coverage holes degrade the performance and reduce the lifetime of UWSNs. In this paper, we present an Intelligent Depth Based Routing (IDBR) scheme which addresses this issue and contributes towards maximization of network lifetime. In our proposed scheme, we allocate initial energy to the sensor nodes according to their usage requirements. This idea is helpful to balance energy consumption amongst the nodes and keep the network functional for a longer time as evidenced by the results provided

    Comparing Log-based and Exponent-based Functions to Predict Human Height by Foot Length

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    Background: Human height estimation is critical in medicolegal cases. This anthropometric measurement not only reveals racial differences but also aids police investigation to narrow down. Foot size varies in different races and ethnic groups, because of genetic influence on development height. The present study aimed to explore the relationship between foot size and the height of a person in a particular context. The current research also compared log-based function and exponent-based function to explore which best fits the relation between age, foot size, and height.Methods: This cross-sectional study included foot measurements from 240 participants of 6 different age groups in the age range of 2-21 years. Foot length and height were recorded as per standard methods after obtaining ethical approval from the Institutional Review Board of COMSATs University Islamabad Pakistan and gaining consent from the study participants. Correlation and regression analyses were performed using SPSS V 23. In this study, two mathematical functions of log-based and exponent-based were compared to more accurately predict the behavior of two variables. The appropriateness of these candidate functions was evaluated using statistical parameters, including the Sum of Squared Errors (SSE), R2, adjusted R2, and Root Mean Square Error (RMSE).Results: The mean height of male participants of the age group of 3-5 years was higher than that of the female participants. Among 6-10-year-olds and 11-15-year-olds, female participants presented a greater height than males. In the age groups of 16-20 and ≥21 years, males were taller than females. The average foot size of males and females of all age groups was 22.09 cm and 20.44 cm, respectively. The exponent-based candidate functions best fitted the relationship between age, foot size, and height, compared to the log-based candidate function.Conclusion: Foot size indicated the highest correlation with height and minimum standard error in the estimation of stature. Therefore, foot size provided the highest reliability and accuracy in estimating height

    Evolutionary algorithm based heuristic scheme for nonlinear heat transfer equations.

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    In this paper, a hybrid heuristic scheme based on two different basis functions i.e. Log Sigmoid and Bernstein Polynomial with unknown parameters is used for solving the nonlinear heat transfer equations efficiently. The proposed technique transforms the given nonlinear ordinary differential equation into an equivalent global error minimization problem. Trial solution for the given nonlinear differential equation is formulated using a fitness function with unknown parameters. The proposed hybrid scheme of Genetic Algorithm (GA) with Interior Point Algorithm (IPA) is opted to solve the minimization problem and to achieve the optimal values of unknown parameters. The effectiveness of the proposed scheme is validated by solving nonlinear heat transfer equations. The results obtained by the proposed scheme are compared and found in sharp agreement with both the exact solution and solution obtained by Haar Wavelet-Quasilinearization technique which witnesses the effectiveness and viability of the suggested scheme. Moreover, the statistical analysis is also conducted for investigating the stability and reliability of the presented scheme

    Tachism: Tri-Port Antenna with Triple Notching Characteristic and High Isolation System for MIMO Application

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    A novel ultra-wideband (UWB) KAYI-shaped and common KITE-shaped ground plane tri-port antenna is proposed. The proposed research work has a small size of (30 × 30 × 1.6 mm3). The MIMO antenna elements are placed in a KAYI-shaped (Y-shaped) with a symmetric phase shift of 120∘ between the nearby MIMO antennas element improving the isolation. The antenna’s gain is more than 5 dBi for the entire bands of WiMax, WLAN, and X-band satellite communication. The suggested work includes notches at 3.2 GHz, 5.2 GHz, and 8.9 GHz, respectively. The notching characteristics are made possible by L-shaped slits for the WiMax band, the inverted U-shaped slot for WLAN, while the third is created by the interaction between the L-shaped and U-shaped notching elements. Results were measured after making the prototype antenna on the FR-4 substrate. The proposed antenna has good impedance matching for 2–20 GHz and three notching characteristics with high isolation among the MIMO elements. Mean effective gain (MEG), envelope correlation coefficient (ECC), and total active reflection coefficient (TARC) are the diversity metrics of MIMO antennas which are in good comparison to the proposed antenna. The antenna is a good candidate for deployment in wireless communication and MIMO applications

    Unknown parameters achieved by G.A, IPA and GA-IPA for δ = 2.0.

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    <p>Unknown parameters achieved by G.A, IPA and GA-IPA for δ = 2.0.</p

    Δημοκρατική κατήχησις / Γ. Λ. Αρβανιτάκη.

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    Radio refractivity plays a significant role in the development and design of radio systems for attaining the best level of performance. Refractivity in the troposphere is one of the features affecting electromagnetic waves, and hence the communication system interrupts. In this work, a modified artificial neural network (ANN) based model is applied to predict the refractivity. The suggested ANN model comprises three modules: the data preparation module, the feature selection module, and the forecast module. The first module applies pre-processing to make the data compatible for the feature selection module. The second module discards irrelevant and redundant data from the input set. The third module uses ANN for prediction. The ANN model applies a sigmoid activation function and a multi-variate auto regressive model to update the weights during the training process. In this work, the refractivity is predicted and estimated based on ten years (2002-2011) of meteorological data, such as the temperature, pressure, and humidity, obtained from the Pakistan Meteorological Department (PMD), Islamabad. The refractivity is estimated using the method suggested by the International Telecommunication Union (ITU). The refractivity is predicted for the year 2012 using the database of the previous ten years, with the help of ANN. The ANN model is implemented in MATLAB. Next, the estimated and predicted refractivity levels are validated against each other. The predicted and actual values (PMD data) of the atmospheric parameters agree with each other well, and demonstrate the accuracy of the proposed ANN method. It was further found that all parameters have a strong relationship with refractivity, in particular the temperature and humidity. The refractivity values are higher during the rainy season owing to a strong association with the relative humidity. Therefore, it is important to properly cater the signal communication system during hot and humid weather. Based on the results, the proposed ANN method can be used to develop a refractivity database, which is highly important in a radio communication system

    Statistical analysis for heat transfer problems.

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    <p>Statistical analysis for heat transfer problems.</p
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