A neural–genetic (NN–GA) approach for optimising mechanisms having joints with clearance

In this paper, a dimensional synthesis method for a four-bar (4R) path generator mechanism having revolute joints with clearance is presented. Joint clearances are considered as virtual massless links. The proposed method uses a neural network (NN) to define the characteristics of joints with clearance with respect to the position of the input link, and a genetic algorithm (GA) to implement the optimization of link parameters using an appropriate objective function based on path and transmission angle errors. Training and testing data sets for network weights are obtained from mechanism simulation, and Grashof’s rule is used during the optimization process as constraint. The results show that the proposed method is very efficient for the purpose of modeling the joint variables and also adjusting the link dimensions to optimize planar mechanisms with clearances.     

Knowledge construction and misconstruction: A case study approach in asynchronous discussion using Knowledge Construction – Message Map (KCMM) and Knowledge Construction – Message Graph (KCMG)

This paper introduces a methodology for analyzing the knowledge construction and misconstruction processes occurring in online asynchronous discussion for Secondary 2 (Grade 8) students. The use of purposive sampling targeting specific students in a single course forum could potentially advance understanding of these processes using Knowledge Construction – Message Map (KCMM) and Knowledge Construction – Message Graph (KCMG). This paper traced the communication patterns and knowledge construction as well as misconstruction processes of students working in groups to formulate scientific ideas. This methodology reveals the dynamics of asynchronous discussion through mapping and quantifying the electronic learning process. This will equip educational practitioners and researchers with a useful tool for describing online interaction through adoption of a measurement methodology more systematic and effective than anecdotally. The research findings suggest that self-directed learning through asynchronous discussion has to be monitored by facilitators as learners possessed misconceptions that could potentially mislead other participants.     

Knowledge construction and misconstruction: A case study approach in asynchronous discussion using Knowledge Construction – Message Map (KCMM) and Knowledge Construction – Message Graph (KCMG)

This paper introduces a methodology for analyzing the knowledge construction and misconstruction processes occurring in online asynchronous discussion for Secondary 2 (Grade 8) students. The use of purposive sampling targeting specific students in a single course forum could potentially advance understanding of these processes using Knowledge Construction – Message Map (KCMM) and Knowledge Construction – Message Graph (KCMG). This paper traced the communication patterns and knowledge construction as well as misconstruction processes of students working in groups to formulate scientific ideas. This methodology reveals the dynamics of asynchronous discussion through mapping and quantifying the electronic learning process. This will equip educational practitioners and researchers with a useful tool for describing online interaction through adoption of a measurement methodology more systematic and effective than anecdotally. The research findings suggest that self-directed learning through asynchronous discussion has to be monitored by facilitators as learners possessed misconceptions that could potentially mislead other participants.     

A linear-time algorithm for finding Hamiltonian (<Emphasis Type="Italic">s</Emphasis>, <Emphasis Type="Italic">t</Emphasis>)-paths in odd-sized rectangular grid graphs with a rectangular hole

A grid graph \(G_{\mathrm{g}}\) is a finite vertex-induced subgraph of the two-dimensional integer grid \(G^\infty \). A rectangular grid graph R(m, n) is a grid graph with horizontal size m and vertical size n. A rectangular grid graph with a rectangular hole is a rectangular grid graph R(m, n) such that a rectangular grid subgraph R(k, l) is removed from it. The Hamiltonian path problem for general grid graphs is NP-complete. In this paper, we give necessary conditions for the existence of a Hamiltonian path between two given vertices in an odd-sized rectangular grid graph with a rectangular hole. In addition, we show that how such paths can be computed in linear time.     

Classification of radar echoes with a textural–fuzzy approach: an application for the removal of ground clutter observed in Sétif (Algeria) and Bordeaux (France) sites

This work deals with the classification of radar echoes and the removal of clutter caused by the Earth’s surface. Two incoherent radar sites are considered, which are the regions of Sétif (Algeria) and Bordeaux (France) where different climates and landforms prevail. To perform this task, we used a combination of textural and fuzzy approaches. For the textural technique, we applied grey-level co-occurrence matrices that are widely used in the analysis of texture images. We have shown that among nine parameters, only energy and local homogeneity are considered to be effective in discriminating between precipitation echoes and clutter. Then, these parameters are used as inputs for the fuzzy system, while the two radar echo types are its output classes. Image processing done by using this approach has reduced ground echoes by more than 93.5% for Sétif and 92.3% for Bordeaux sites, while more than 97.6% of precipitation echoes are stored at both sites. In addition, over 96% of the anomalous propagations observed only in Bordeaux site are removed. The proposed approach gives a filtering average rate that is 94.5% higher than that obtained for the textural technique alone, which is 91.5%.     

Study of the Radio Frequency (RF) performance of a Wafer-Level Package (WLP) with Through Silicon Vias (TSVs) for the integration of RF-MEMS and micromachined waveguides in the context of 5G and Internet of Things (IoT) applications: Part 1—validation of the 3D modelling approach

Microsystem Technologies - Packaging of Radio Frequency MicroElectroMechanical-Systems (RF-MEMS) and other passive components is a delicate issue, especially in the riverbed of upcoming application...