Estimation of Antenna Correlation Coefficient of N-Port Lossy MIMO Array

This paper proposes a simple yet accurate method for estimating the antenna correlation coefficient (ACC) of a high-order multiple-input multiple-output (MIMO) antenna. The conventional method employed to obtain the ACC from three-dimensional radiation patterns is costly and difficult to measure. An alternate method is to use the S-parameters, which can be easily measured using a network analyzer. However, this method assumes that the antennas are highly efficient, and it is therefore not suitable for lossy MIMO antenna arrays. To overcome this limitation, we define and utilize the non-coupled radiation efficiency in the S-parameter-based ACC formula. The accuracy of the proposed method is verified by the simulation results of a 4-port highly coupled lossy MIMO array. Further, the proposed method can be applied to N-port arrays by expanding the calculation matrix.     

Effect of Ni on Microstructure and Mechanical Properties of CrMnFeCoNi High Entropy Alloy

The effect of Ni content on microstructure and mechanical properties of the CrMnFeCoNi high entropy alloy (HEA) has been studied. The Ni content varied from 0 to 20 at% in the composition (CrMnFeMn)_100?xNi_x, where x?=?0, 2.5, 5, 10, 15, and 20 at%. The alloys were synthesized by vacuum arc melting and the microstructure as well as hardness of the as-cast alloys were studied. Alloys with low Ni content (x?≤?2.5%) consists of a two-phase microstructure of dendritic and inter-dendritic regions with fcc (matrix) and tetragonal (sigma) crystal structure, respectively. When the Ni content is 5 at%, two-phase structure with fcc (matrix) and bcc (secondary phase) is observed, with the addition of Mn-rich inclusions that are present in the entire matrix. Alloys with higher Ni content (x?≥?10, at%) exhibit a single phase of fcc structure. Hardness of the HEAs decreases from 320 to 120 Hv with increase in Ni content, and the high hardness of these alloys with low Ni content is due to the mixture of both fcc and hard tetragonal (sigma) phases.

     

The extent of knowledge of Quick Response Manufacturing principles: an exploratory transnational study

The main goal of this research is to identify whether companies that have implemented the Quick Response Manufacturing (QRM) approach have full knowledge of the QRM principles or have merely applied the elements (principles and tools) that have a close relationship with Lean Manufacturing. Based on a review of the literature regarding the QRM principles, an exploratory survey was conducted for over 20 manufacturing companies from Brazil, Europe and the USA that operate in an Engineer or Make to Order environment system and explicitly have conducted QRM journeys. The results of the present study show that (i) the surveyed companies have difficulty knowing and applying some of the exclusive elements of this approach, even if they started implementing QRM several years ago; (ii) the surveyed companies’ knowledge degree over QRM exclusive elements is apparently higher among US-based companies due to better trained employees and better dissemination and awareness of the QRM exclusive elements; and (iii) a mentality based on productivity, low costs and due date delivery was identified as the main barrier for companies to achieve a higher knowledge degree regarding QRM.     

Sustainability of process improvements: an application of the experiential learning model (ELM)

Despite the pervasiveness of process improvement (Lean or Six Sigma) programmes, there is a rising concern regarding the sustainability of these programmes. Several studies point out that initial operational efficiency gains as a result of these programmes simply disappear over time. Using process improvement implementation experiences in an aircraft manufacturing and distribution operation, we studied long-term sustainability of process improvement events. We found that process owners of successful improvement events applied experiential learning model (ELM). The ELM is a cycle of – (1) concrete experience, (2) reflective observations, and (3) abstract conceptualizations, and (4) active experimentation. This study finds that when the ELM cycle is repeated many times over an extended period to continuously improve, and documented using A3 reports, that the improvement is sustained.     

A pilot level approach to remove anionic species from industrial effluents using a novel carbonate-steam pyrolysed activated charcoal system

In our laboratory, we synthesized a novel surface tailored activated charcoal in removing nitrite species from fertilizer industrial effluents. A customized high temperature carbonate-steam activation technique was adopted to develop the sodium carbonate impregnated activated charcoal (SCIAC). The surface properties of the material were determined using SEM, TG and X-RD techniques. Batch adsorption experiments were performed for optimizing various conditions such as solution pH, contact time, temperature and adsorbent dose for maximizing the nitrite adsorption onto SCIAC. Considerably, a very high nitrite adsorption percentage of 83.8 was obtained for an initial nitrite concentration of 5.0?mg/L at pH 3.0. Among the various equilibrium and kinetic models, Freundlich and pseudo-second-order expressions, respectively, were well enough to explain the adsorption processes. In general, it may conclude that the change in surface characteristics of the adsorbent material after the pyrolysis process is highly favorable for effective removal of nitrite ions from aqueous systems. Adsorption capacity of SCIAC was 27.03?mg/g and studies revealed that the material was feasible in removing nitrite from industrial effluents.     

Design and implementation of low complexity circularly symmetric 2D FIR filter architectures

Multidimensional Systems and Signal Processing - This paper presents a low complexity two dimensional (2D) circular symmetric Finite Impulse Response (FIR) filter design and implementation of...     

Salient objects detection in dynamic scenes using color and texture features

Visual saliency is an important research topic in the field of computer vision due to its numerous possible applications. It helps to focus on regions of interest instead of processing the whole image or video data. Detecting visual saliency in still images has been widely addressed in literature with several formulations. However, visual saliency detection in videos has attracted little attention, and is a more challenging task due to additional temporal information. A common approach for obtaining a spatio-temporal saliency map is to combine a static saliency map and a dynamic saliency map. In our work, we model the dynamic textures in a dynamic scene with local binary patterns to compute the dynamic saliency map, and we use color features to compute the static saliency map. Both saliency maps are computed using a bio-inspired mechanism of human visual system with a discriminant formulation known as center surround saliency, and are fused in a proper way. The proposed model has been extensively evaluated with diverse publicly available datasets which contain several videos of dynamic scenes, and comparison with state-of-the art methods shows that it achieves competitive results.     

Breast cancer diagnosis in an early stage using novel deep learning with hybrid optimization technique

Multimedia Tools and Applications - Breast cancer is one of the primary causes of death that is occurred in females around the world. So, the recognition and categorization of initial phase breast...     

Performance evaluation and implementation of convolution coded OFDM modem in wireless underwater acoustic communication

High‐data transmission rate and reliable communication in underwater acoustic channel is challenging because of limited bandwidth, multipath propagation, and Doppler shift, which results in poor bit error performance. Under this constraint, this paper explains the simulation results of underwater wireless acoustic data transmission system by using quadrature phase shift keying modulation with convolution encoder at the transmitter and proposed Viterbi decoder at the receiver. The decoder algorithm in comparison with MATLAB inbuilt function shows asserting improved results. This paper evaluates the performance of convolution coded orthogonal frequency division multiplexing modem, which is studied over typical underwater channel through an extensive computer simulation and a semirealistic experimentation. The performance of convolution coded orthogonal frequency division multiplexing system is measured in time domain plots, bit error rate curves, and number of bit errors per frame over additive white Gaussian noise and Rayleigh channel conditions.