In this paper the Reflection coefficient of electromagnetic wave incidence on the walls of the buildings and obstacles that occurs in mobile communication path was modified by solving the Riccati nonlinear equations. For this purpose, the building walls are assumed inhomogeneous layers where their permittivity changes as function of the wall thickness. Using this Reflection coefficient, a new propagation model based on urn and GID (uniform geometrical theory of diffraction and geometrical theory of diffraction) for multiple diffraction paths is proposed. Using this model, the diffraction loss as well as the path loss for a row of buildings with two in homogeneous faces is calculated and compared with measured data. Comparison of theoretical and measured results reveals that the modified Reflection coefficient can adequately predict the reflective properties of the building walls. Moreover, results obtained with the proposed UID model are in good agreement with the measurement data. Therefore, the modified Reflection coefficients well as the new UID model can be used for estimation of multipath signals strength, diffraction loss and also path delay in ray tracing algorithms used in mobile communication, radar and radio links.

Objective: To predict loss reserve using a stochastic approach and compare it with the proposed deterministic methods in the central insurance directive of the method of estimating and controlling the adequacy of loss reserves in the field of automobile third party liability insurance. Methodology: This research is an applied-development study in terms of its objectives and is considered as an analytical study. In this paper, stochastic and definite methods are used to calculate the loss reserve. To evaluate the model, a loss data set of an Iranian insurance company in the period 2011 to 2019 is considered; using this data set as well as designing a run-off triangle generation algorithm, loss reserve was analyzed based on the studied models by R software. The run-off triangle generation algorithm designed in this paper has the ability to generate a double run-off triangle (triangles of number and amount of loss) simultaneously. In this paper, in addition to using common methods of back-testing the results, a solution is proposed to select the best reserving model based on the calculation of the uncertainty of consecutive triangles. Findings: Due to the definiteness of the proposed central insurance models, the use of stochastic approaches was emphasized in this paper. In the central insurance approach, it is not possible to calculate CDR and MSEP. These two criteria are very valuable in response to the insurance company's solvency and risk-based supervision. In this article, several loss reserve methods were used to show how the best method can be selected for loss reserve. The dynamic stochastic approach used in this paper allows insurance companies, in addition to estimating the reserve point, to determine the safe distance for it and thus save sufficient capital to fulfill their obligations. Conclusion: The results of the calculations in this paper indicate that the method based on the loss ratio is biased and the results are not reliable for insurance companies. The simulation results also confirm the inadequacy of the method based on the damage ratio. The results of the study show that it is not possible to recommend a fixed and uniform method for all companies. It is the insurance company's duty to find the most appropriate method for its company and to introduce it to the supervisory body.

Purpose: To report visual and anatomical outcome of flap loss after LASIK surgery for correction of high myopia. Materials & Methods: Retrospective evaluation of flap loss in two eyes of two patients, a rare complication of LASIK Surgery. Case No. 1: 27 y/o woman with Ref. OD -9.75; 2.75*177 VA. CC: 20/60 KR OD: 41.86*77 39.86 * 168 & partial amblyopia due to anisometropia. Case No. 2: 38 y/o woman with Ref OD. -9.50 1.0*177 VA CC: 20/30 KR OD: 42.06*77 40.99 * 167. Results: In both patients during LASIK surgery free cap complication occurred and after Laser therapy free cap positioned over the stromal bed, but the next day after operation flaps were lost. For case NO.1only medical management performed and after 4.5 years F/U cornea has 2° central haziness. For case NO.2 another corneal flap from donor globe cut and sutured with Nylon 10/0 and after 18 months F/U cornea is clear. Conclusion: In patients with flat keratometry less than 41.0 Diopter rate of free cap are high and after laser therapy for high myopia the keratometry became more flat. If surgeon doesn't suture flap the rate of flap loss increase so for prevent of corneal haziness and corneal ectazia this evaluation suppose to perform donor corneal flap graft.      

2Various researches have shown that Iran's educational system does not pay enough attention to cultural differences and mostly promotes the dominant and official national culture in an engineered way. The focus of these researches has been focused on the inputs of the educational system. The current research, relying on the mixed exploratory method, tried to examine both the inputs and educational processes in order to test the truth of this claim, whether such a claim is consistent with the reality in the educational system. In this way, in the qualitative part, first the teachers' lived experiences of the criteria that were considered for their selection and employment were analyzed (inputs), and then in the quantitative part, the teacher's success in the classroom was analyzed. It was predicted based on the mentioned criteria (processes). The findings of this research showed that scientific identity and ideological identity are valued in the recruitment of teachers, and because of this, criteria such as personal success, special privileges, and religious and moral foundations are put forward. However, it is only the teacher's personal success that can predict his success in the classroom. This shows that the ideological identity is only manifested in the inputs and is practically not institutionalized in the classroom and teaching processes. In this way, considering Iran's educational system as ideological does not match the realities of the educational system.

The electronic properties of thin films and nanostructures as well as the surface electronic structure can be obtained using Reflection electron energy loss technique at low energy. In this study, dielectric function of SrTiO3 is obtained by Yubero-Tougaard method using the experimental inelastic cross section obtained by Tougaard-Chorkrndorf method. Theoretical cross section obtained at energy 1423 eV, incidence angle 15° and exit angle 35° was found to be in good consistency with experimental cross section. In addition, the angular distribution of the surface excitation parameter for this crystal was determined at energies 1000, 1423, 2000, 2500 and 3000 eV. To this end, the definition presented by Pauly and Tougaard was used which relies on the variation in excitation probability at surface and moving in semi-infinite medium. This parameter was calculated based on the differential inelastic electron dispersion cross section using QUEELS software, which is valid for Reflection electron energy loss spectrum.

Purpose: Report a case of iatrogenic medial rectus loss in exotropia surgery and its management with review literature.Case Report: A 14-year-old female with a history of cerebral palsy and left exotropia underwent strabismus surgery in another center when she was 7 years old. As her surgeon reported, after 8 mm medial rectus resection, it was lost and he could not retrieve it; so, to balance the forces of adduction and abduction, the surgeon disinserted left lateral rectus, but 2 months later, because of large angle exotropia and severe limitation in adduction, she was referred to this center. We explored the area and could not find the lost medial rectus; so, half tendon transposition of superior rectus and inferior rectus to the previous insertion site of medial rectus was performed and left lateral rectus was fixated to the lateral orbital periosteum. Two months after the operation, she was orthotropic and ocular movements were significantly balanced.Conclusion: Half tendon transposition of vertical recti to the site of lost medial rectus associated with periosteal fixation of lateral rectus can improve the strabismus of lost medial rectus muscle.

In this article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of statistical energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the statistical energy analysis method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from modeling with this method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

M-type hexaferrite SrFe9Mn1.5 Ti1.5O19 and BaFe9Mn1.5 Ti1.5O19 were synthesized by usual ceramic sintering method. The powders of the 70% ferrites by weight were mixed with resin epoxy. The prepared composite was sprayed on a 1.8mm-thick aluminum 5083 substrate. Their structure and microwave adsorption property were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), and vector network analyzer. The results showed that the magnetoplumbite structure for both samples was formed and powders had the hexagonal or amorphous morphology with particle sizes within the range of 1-5mm. The maximum Reflection loss for Sr-ferrite coating was 18.84 GHz equal to (-26.43 dB). The waveband of absorption was approximately 3GHz more than 15dB for Reflection losses. The results for Ba-ferrite were 19.18GHzwith (-44.lldB) Reflection loss and 3.2 GHz waveband. Both coatings can be good candidates for stealth radar targets.