Positioning and navigation of mobile robot

Positioning tracking is not a new idea as we have been seen from the ability of the GPS (Global Positioning System) to track the position of the object, in general with acceptable accuracy but the cost of GPS installation is expensive. However, in the case of detecting the exact position in signal-blocked closed environment (e.g. inside building, forest, mines and others); the accuracy factor provide by GPS is low. Thus, this project presents a positioning tracking system that is able to track the movement of an object within a small area or inside buildings. A complete set of the positioning tracking system consists of a pair of computer mechanical mouse and a microcontroller. From the position displayed on the computer screen, the position of the object can be located. The pair of mouse detects each movement of the object and sends the movement data to microcontroller. Linear, angular displacement and positioning calculation are also being discussed. From the results, it’s shown that the positioning system is applicable. However, some small errors are also occurred but in acceptable range. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Study on acrylamide-vinyl pyrrolidone copolymer

Summary The solution copolymerization of acrylamide (AAm) with N-vinyl pyrrolidone (NVP) was investigated using azobisisobutyronitrile (AIBN) as an initiator at 60°C. The study was performed by measuring the rate of the copolymerization reaction, the molecular weights and by determining the monomer reactivity ratios. In addition, the thermal properties (thermal conductivity, thermal diffusivity and volumetric heat capacity) of the resulted copolymers in aqueous solutions were investigated at various temperatures. The kinetic results and the apparent reactivity ratios indicate that NVP is more reactive than AAm towards the copolymerization process. The values of the thermal properties whowed that the behaviour of such parameters depend on the polymer concentration, the temperatures and the content of vinyl pyrrolidone in the copolymeric chains.     

Moving Objects Localization by Local Regions Based Level Set: Application on Urban Traffic

In this paper, a novel method for locating multiple moving objects in a video sequences captured by a stationary camera is proposed. In order to determine the precise location of the objects in an image, a new local regions based level set model is carried out. The whole process consists of two main parts: the global detection and the fine localization. During the global detection, the presence or absence of an object in an image is determined by the Mixture of Gaussians method. For the fine localization, we propose to reformulate global energies by utilizing little squared windows centered on each point over a thin band surrounding the zero level set, hence the object contour can be reshaped into small local interior and exterior regions that lead to compute a family of adaptive local energies, which enables us to well localize the moving objects. Moreover, we propose to adapt the smoothness of the contours, and the accuracy of the objects’ perimeter of different shapes with an automatic stopping criterion. The proposed method has been tested on different real urban traffic videos, and the experiment results demonstrate that our algorithm can locate effectively and accurately the moving objects; optimize the results of the localized objects and also decrease the computations load.     

Utilization of composite’s tensile properties for energy absorbing systems

This idea was inspired by the fact that huge energy absorption capability can be achieved if the longitudinal properties of composite structures are being utilized. This can only be done if the energy absorbing system postfailure scenario is mitigated to be tearing failure mechanism. In this paper, friction, crazing, circumferential expansion and tearing failure mechanisms were introduced and applied successfully to control the response of energy absorbing system to the applied load. The system was designed by slipping a solid cone into composite cone. The semi-cone angles used were 8°, 12°, 16° and 20°. The cone height and bottom diameter were kept constant for all cases as 100 mm and 76.2 mm, respectively. Force–stroke curves and deformation histories of typical specimens are presented and discussed. The results demonstrated that at first crush stage the energy is dissipated in the form of friction and crazing and the conical responded in an elastic manner, while the post-crush stage is dominated by tearing failure mechanisms.     

Shelf life assessment of MalaysianPangasius sutchi during cold storage

The findings of the present work yield useful information about the MalaysianPangasius sutchi concerning the marketing sector from the point of view of shelf life and storage temperature in the range of 0 to 10‡C. A fresh batch of typical samples, were stored similarly in four chillers of different temperatures for a period of 28 days. During the course of storage, the samples were periodically subjected to pH and sensory tests performed by trained panelists. Experimental observations were analysed and regressed to develop three correlations. The first one was between the sensory tests and the storage time and temperatures, while the second one related pH values to storage time and temperatures. Finally, a correlation between sensorial and pH values was developed as well. The first correlation is presented in tabular form to yield a simple guide to fish retailers, by which quality and shelf life of the displayed fish commodity may be estimated.     

Site-selective spectroscopy of Eu-doped orthorhombic lanthanum and monoclinic yttrium polyphosphates

In order to study the influence in the change of the coordination environment of the cationic sites on the luminescent properties of rare-earth ions doping polyphosphates Ln(PO₃)₃ (Ln = La, Y) with two different structures, the time-resolved luminescence of the Eu³⁺ ion, used as structural probe, is reported. La(PO₃)₃ has an orthorhombic structure in which only one position with eight coordination is available for the cation, while Y(PO₃)₃ adopts the Yb(PO₃)₃ structure in which four slightly different octahedral sites are available for the trivalent rare-earth ion. Site-selective excitation of the ⁵D₀ level was performed and luminescence decay times of each Eu³⁺ site were measured at 77 K. The spectroscopic results are discussed and correlated with the structural data.     

Synthesis, structure refinement and characterization of tetrahydrated acid gadolinium diphosphate HGdP2O7·4H2O

Synthesis and single crystal structure are reported for a new gadolinium acid diphosphate tetrahydrate HGdP₂O₇·4H₂O. This salt crystallizes in the monoclinic system, space group P2₁/n, with the following unit-cell parameters: a = 6.6137(2) Å, b = 11.4954(4) Å, c = 11.377(4) Å, β = 87.53(2)° and Z = 4. Its crystal structure was refined to R = 0.0333 using 1783 reflections. The corresponding atomic arrangement can be described as an alternation of corrugated layers of monohydrogendiphosphate groups and GdO₈ polyhedra parallel to the () plane. The cohesion between the different diphosphoric groups is provided by strong hydrogen bonding involving the W4 water molecule.

IR and Raman spectra of HGdP₂O₇·4H₂O confirm the existence of the characteristic bands of diphosphate group in 980–700 cm⁻¹ area. The IR spectrum reveals also the characteristic bands of water molecules vibration (3600–3230 cm⁻¹) and acidic hydrogen ones (2340 cm⁻¹). TG and DTA investigations show that the dehydration of this salt occurs between 79 and 900 °C. It decomposes after dehydration into an amorphous phase. Gadolinium diphosphate Gd₄(P₂O₇)₃ was obtained by heating HGdP₂O₇·4H₂O in a static air furnace at 850 °C for 48 h.     

Automatic COVID-19 detection mechanisms and approaches from medical images: a systematic review

Multimedia Tools and Applications - Since early 2020, Coronavirus Disease 2019 (COVID-19) has spread widely around the world. COVID-19 infects the lungs, leading to breathing difficulties. Early...     

Determination of apolar and minor polar compounds and other chemical parameters for the discrimination of six different varieties of Tunisian extra-virgin olive oil cultivated in their traditional growing area

A study on the characterization of Tunisian extra-virgin olive oil varieties produced in their place of origin has been carried out. Due to the influence of the genotype and environmental, agronomic and technological factors on the chemical composition of olive oil and its quality, all the olives studied were collected on the same season, and the oil was obtained under the same processing technique. Several analyses were performed to characterize the different olive oils: free acidity, peroxide value, fatty acid composition, radical scavenging activity, Rancimat assay, pigments content and phenolic compounds by HPLC–MS. In order to evaluate all the results obtained (36 parameters for each variety), different statistical analyses were used to discriminate the extra-virgin olive oil varieties: one-way analysis of variance was performed to check significant differences among cultivars (p ≤ 0.05); PCA was applied to the data showing that variables such as oleic, linoleic, quinic and vanillic acids, apigenin, luteolin, taxifolin, oleuropein aglycon, pinoresinol acetate, elenolic acid and oxidative stability allowed discriminating among the different varieties of extra-virgin olive oil studied. Besides, LDA model was able to classify the samples depending on their geographical origin in Tunisia (North, Centre and South).     

Effect of self-phase-modulation on dispersion compensated absolute polar duty cycle division multiplexing transmission

The effect of self-phase modulation (SPM) on 40 Gb/s absolute polar duty cycle division multiplexing (AP-DCDM) is investigated and reported. The study includes the influence of launched power, number of channels and dispersion compensation method. Dispersion post-compensation and combination of dispersion pre- and post-compensation are used to manage the transmission links. At high powers, SPM degrades the pulse recompression process and provides an upper bound on the AP-DCDM transmitted pulse energy. It is demonstrated that the 40 Gb/s AP-DCDM system shows a 4.1 dB improvement and less than 1 dB penalty in terms of SPM tolerance in comparison to 40 Gb/s 4-ary and on off-keying (OOK) systems, respectively. The SPM effect is stronger in the 100 post-compensated link than that in the combination of pre- and post-compensated links. Dispersion pre-compensation of 18 22 is found as the optimum range of pre-compensation ratio for AP-DCDM system, which makes optimisation of the launched power possible.