In this paper, we study the incorporation of the commensalism interaction and harvesting on the Lotka–Volterra food chain model. The system provides one commensal prey, one harvested prey, and two predators. A set of preliminary results in local bifurcation analysis around each equilibrium point for the proposed model is discussed, such as saddle-node, transcritical and pitchfork. Some numerical analysis to confirm the accruing of local bifurcation is illustrated. To back up the conclusions of the mathematical study, a numerical simulation of the model is carried out with the help of the MATLAB program. It can be concluded that the system's coexistence can be achieved as long as the harvesting rate on the second prey population is lower than its intrinsic growth rate. Further, the role of mutual interaction can lead to the stability of the proposed system.
The mechanical design of elevator elements is always performed by international standards. The engineer selects the appropriate elements of elevator according to catalogues without knowing scientific details. Therefore, a theoretical analysis is achieved at two operating conditions for guide rails (1) safety gear operation, and (2) running condition with the loads unevenly distributed on the elevator car. The guide rail is considered a continuous beam with variable supports. Then the British code is listed showing the equations used in it.
The theoretical equations showed that guide rails are never subjected to stress in simultaneous combined buckling and bending in the plane, where the bending moment is exerted. It is always a c
... Show MoreThe present study tackles the scientific model and the mechanisms of operating in the formation of the image of the artistic work to create a scene that cares for the aesthetic decoration through raw and techniques and employing them to express the aesthetic values that care for what is not familiar and deviation from the familiar in the visual exhibition and the care for the employment of the technical abilities, lighting, and sound as well as the employment of multiple materials. The research presents the objectives of his study in the exhibition hall of Natural History Museum (University of Baghdad) to create an aesthetic and expressive state at the same time. Then, in the theoretical framework the researcher traces the experiments of
... Show MoreShell model and Hartree-Fock calculations have been adopted to study the elastic and inelastic electron scattering form factors for 25Mg nucleus. The wave functions for this nucleus have been utilized from the shell model using USDA two-body effective interaction for this nucleus with the sd shell model space. On the other hand, the SkXcsb Skyrme parameterization has been used within the Hartree-Fock method to get the single-particle potential which is used to calculate the single-particle matrix elements. The calculated form factors have been compared with available experimental data.
This paper presents a grey model GM(1,1) of the first rank and a variable one and is the basis of the grey system theory , This research dealt properties of grey model and a set of methods to estimate parameters of the grey model GM(1,1) is the least square Method (LS) , weighted least square method (WLS), total least square method (TLS) and gradient descent method (DS). These methods were compared based on two types of standards: Mean square error (MSE), mean absolute percentage error (MAPE), and after comparison using simulation the best method was applied to real data represented by the rate of consumption of the two types of oils a Heavy fuel (HFO) and diesel fuel (D.O) and has been applied several tests to
... Show MoreThis paper compares between the direct and indirect georeferencing techniques in Photogrammetry bases on a simulation model. A flight plan is designed which consists of three strips with nine overlapped images for each strip by a (Canon 500D) digital camera with a resolution of 15 Mega Pixels.
The triangulation computations are carried out by using (ERDAS LPS) software, and the direct measurements are taken directly on the simulated model to substitute using GPS/INS in real case. Two computational tests have been implemented to evaluate the positional accuracy for the whole model and the Root Mean Square Error (RMSE) relating to (30) check points show that th
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After the defeat of the military terrorist organization "ISIS" and the fall of the throne of its alleged state in the Iraqi city of Nineveh, in Syrian Baghouz, and the end of its control over the land, the Syrian camps, especially "Al-Hol" camp, emerge as an incubator for the ideology of the terrorist organization "ISIS" and a vital base for its consolidation and dissemination, which includes (68,000- 73,000) people. During the years following the military defeat of (ISIS), the camp witnesses the spread of extremist ideas widely at the hands of its residents, including the families of the organizations dead's, extremist detainees, and those who deal with it, taking advantage of the deterioration of the environmental, se
... Show MoreB Saleem, H Alwan, L Khalid, Journal of Engineering, 2011 - Cited by 2
A genetic algorithm model coupled with artificial neural network model was developed to find the optimal values of upstream, downstream cutoff lengths, length of floor and length of downstream protection required for a hydraulic structure. These were obtained for a given maximum difference head, depth of impervious layer and degree of anisotropy. The objective function to be minimized was the cost function with relative cost coefficients for the different dimensions obtained. Constraints used were those that satisfy a factor of safety of 2 against uplift pressure failure and 3 against piping failure.
Different cases reaching 1200 were modeled and analyzed using geo-studio modeling, with different values of input variables. The soil wa