A common method for controlling a group of parallel converters in decentralized control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient controllers. By linearizing and simplifying conditions, the control System conversion function model becomes a single input-single output System, which is efficient enough to show the relationship between control parameters such as slope of droop characteristics and derivative sentences, Virtual impedance, and voltage controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

Deep-sea vessels use various navigational aids like AIS (automatic identification System), ECDIS (electronic chart display and information System), radar, GPS (global positioning System), and etc. vessels use AIS to communicate their navigational characteristics, destinations, and load information. Such data are very helpful for vessel officers; therefore, AIS can be used for communicating the name and position of the vessel as well as navigational signs in the port area. So, this System is very helpful in improving the quality of pilotage as well as improving the safety of navigation in canals like Khur Musa.

Introduction: In today's complex and fast-paced world, traditional educational methods are slow and there is a need to use new technologies in education. Also, the spread of the corona virus helped to make education compulsory in cyberspace. The purpose of the current research was to validate the model of professional competencies of online education teachers of the first secondary school. Method: The research method was a descriptive survey type. The statistical population included all teachers of the first secondary school in Golestan province, whose number was about 750 people. The sample was estimated to be 148 people based on Regasi and Morgan's table, who were selected by cluster sampling method. The data collection tool was a researcher-made questionnaire that was prepared based on the results of the qualitative phase. The data was analyzed using smart PLS software and structural equation modeling method. Findings: According to the findings of the research, 89 concepts, 18 subcategories and 7 main categories were confirmed, and the main categories include technical skills, Virtual classroom management, Virtual education ethics, general skills, teaching and learning activities, the cognitive skills and character of the teacher were valid. Conclusion: Therefore, these qualifications should be considered in the selection of teachers and efforts should be made to ensure that the teachers who are teaching have these qualifications.

Ultrasound is the method of choice for many inter-ventions, especially in the abdomen, mainly because of the real-time visualization of the procedure.Most of the liver masses could be precisely localized and biopsied under ultrasound and different methods of tumor ablation which could be performed with ultrasound guidance have been introduced. However, there are some small hepatocellular carcinomas or metastatic lesions, which are well seen on CT scan images but could not be proficiently localized with sonography.Fusion of CT or MR images of the abdomen shows the lesion. Ultrasound imaging is possible in a Virtual navigator System in these cases in which biopsy or RF tumor ablation is possible with US guidance.In this presentation, the method of image fusion and some interesting cases are discussed.-Fusion of CT or MR images of abdomen, which show the lesion, and the ultrasound images is possible in a Virtual navigator System in these cases and biopsy or RF tumor ablation is possible with US guidance.

Background and Objective: Colon cancer is one of the most prevalent cancers among different societies around the world for which some diagnostic modalities have been developed. With CT colonography there is the possibility of observing extracolonic findings which might have significant clinical importance. Here we evaluated the frequencies of extracolonic findings. Subjects and Methods: This cross sectional study was performed from 2016 to 2019 in Isfahan on 402 patients with colon problems who had CT colonography imaging. Data regarding on extracolonic findings with moderate to significant importance were collected by questionnaire from patients ct reports and analyzed. Results: There were significant relationships between total extracolonic findings and findings with moderate importance like: (Abdominal aortic aneurysm below5, Ovarian lesion possibly just a cyst, Lung nodule. Hydronephrosis likely chronic puj, Mesenteric penniculitis, Pancreas cysts, Psoas asymmetry Small pericardial effusion, Small kidney possible renal artery stenosis, Mild porcelain gallbladder) as well as with age These findings were more frequent at older ages (P <0. 001). Discussion: Generally, these results indicated that CT colonography in patients with colon problems especially patients at older ages might lead to find extracolonic findings with high importance like: ( Possible malignancy e, g lung or solid organ mass lymphadenopathy, Abdominal aortic aneurysm more than 5, Bone fracture, Adrenal hemmorhage, Pneumonia, Considerable hydronephrosis, Bone lesion Appendix mucinous tumour, Diverticulitis with abcess or perfusion, Severe porcelain gall bladder).