مجله محاسبات و سامانه های توزیع شده
سال سوم شماره 1 (پیاپی 5، بهار و تابستان 1399)

Today, due to the growing need of various businesses and individuals in the community to use mobile applications to achieve their daily goals, the need for development and availability of various mobile applications is becoming more important. To manage the inherent complexity of the diversity of such programs and to produce and deliver them as quickly as possible, the use of domainspecific modeling languages (DSMLs) can be introduced in specific areas. With this approach, with the use of DSMLs and their related tools, we can hope for more automatic code generation of these programs. This article aims to introduce some successful researches on using model-based development approach in the field of automated or semi-automated production of mobile applications and provide a model-based process with an agile approach to facilitate and speed up the work of mobile application developers.

The high-energy consumption of cloud data centers presents a significant challenge from both economic and environmental perspectives. Server consolidation using virtualization technology is widely used to reduce the energy consumption rates of data centers. In this paper, a hybrid VMP algorithm is proposed based on another proposed improved permutation-based genetic algorithm and multidimensional resource-aware best fit allocation strategy. The proposed VMP algorithm aims to improve the energy consumption rate of cloud data centers through minimizing the number of active servers that host Virtual Machines (VMs). Additionally, the proposed VMP algorithm attempts to achieve balanced usage of the multidimensional resources of active servers, which in turn, reduces resource wastage.

Authentication is one of the main components in security systems and has many challenges and practical applications. Development in biometric technology have led to rapid growth in the field of authentication. The proposed method uses the K-means clustering method to select the appropriate features of the palm image for identification. The first step is to separate the images of different people's palms in terms of similarity, Improving image quality is done by Histogram Equalization method, Then effective features such as Zernike, color histogram and directional histogram are extracted. In the next step, weight is assigned to the features and the indexes that have the best differences between the people in the database will have a higher priority. Finally, the identity of individuals is identified by K-means clustering, Clusters are also updated several times for better results, Each time the amount of error in the clusters is calculated and the best clustering with the least error is selected. In this study, two factors of classification accuracy and amount of calculations were performed to compare the present study with the basic articles and The results showed that 10 features have the lowest error because for every 10 features the clustering score is higher. As a result, the identification of individuals in this study using clustering of characteristics by K-means method was 97.5 percent.

The types of streams and software used in the original mobile case networks were typical. Which does not require support for service quality and delays in the services provided can be ignored. However, the software used in this type of network today is of both multimedia and conventional types. It is clear that multimedia streams need support for service quality and without it, it is not possible to use these streams. Therefore, the protocols used in this type of network must be able to distinguish between streams and establish the quality of service. These issues are due to the nature and properties of wireless networks that should be considered when considering any solution. Unlike conventional wireless networks, mobile case networks do not have centralized and integrated structures such as access points, routers, and amplifiers. For this reason, the solutions provided in this type of network should be decentralized, distributed and based on the cooperation of all nodes in the network. In this article, we have managed and controlled the access of nodes and provided a support method in MANET networks to increase the quality of multimedia streaming service that despite the problems mentioned above has the ability to support service quality.

The existence of nonlinear loads in the distribution network causes many problems for distribution networks. These problems include losses, interference in the performance of protective systems, reduced lifetime of equipment and undesirable performance of motors and capacitors. In the structure of distribution networks, the growth of the use of electronic equipment and the presence of electronic converters have caused harmonic injection and reduced power quality in these networks. In this regard, the use of active filter equipment can reduce harmonics and improve power quality indices in distribution networks. In this paper, an optimization algorithm for teaching and learning is proposed to optimize the classical controller coefficients with the aim of reducing harmonics. Also, Multilayer Perceptron Neural Controller has been used to train algorithm based on intelligent algorithms to reduce network harmonics. The most important features of neural networks are nonlinearity and noise cancellation. In order to perform the simulation of software, the programming environment and simulation of MATLAB software is used.

The rapid development of cloud computing has led to the proliferation of various data centers around the world, that has increased the number of data centers, the number of resources with similar performance but different specifications. Cloud services come with new concepts such as elasticity and scalability. One of the most important differences between traditional services and cloud services is their elasticity. In this paper, a method to improve the resource provisioning for the cloud computing environment is presented, that has four phases of monitor, analysis, plan and execution. In the monitor phase, data is received and the analysis phase, data is pre-processed. The decision phase, that is the most important phase, uses the Bayesian learning technique to decide on the provision of cloud resources. Finally, the result of the decision phase is applied to the resources by the execution phase. The novelty of this paper is the use of Bayesian technique and its combination with the methods used in the analysis phase. The performance results of the proposed method show an increase in elasticity of 5.05% and an increase in elastic accuracy of 6.59% and a scaling rate of 4.31% compared to the compared methods

ract Social networks increasingly host civil society, a place for sharing knowledge, discussing public matters, and conversing private affairs. Social network conversations, as new public spaces, are as important as other large communities for documentation. Network graphs which are related to conversations in public social networks like Twitter, can help us ponder over the role of social networks in human relations. Detection of communities is one of the most important research areas in the field of complex network analysis and applied to better understand the structure of complex networks. In this study, first varieties of communities will be examined in the social network of Twitter, then algorithms which are related to discovery of these communities will be discussed, finally the network of communities resulting from conversations about Coronavirus vaccination will be scrutinized.

Gaining customer trust is one of the key factors and one of the main elements of success in e-commerce. On the other hand, studies show that trust is an important and necessary aspect in accepting e-banking and an essential element for establishing long-term customer relationships with banks. With the development and advancement of communication technology, banks and financial institutions offer new methods in order to provide more services to their customers, one of these new methods is Internet banking. A review of the banking literature reveals the importance of customers' trust in the use of banking services. Accordingly, by identifying the characteristics of Internet banking method and its effect on increasing customer trust, a conceptual model of research was developed. The results showed that the variables of security, user friendliness, usefulness, perceptual ease and awareness and advertising on customer trust They have a significant effect on use. And increases trust and efficiency in the use of electronic banking.

With the increasing advancement of knowledge, the rate of information exchange has increased dramatically. A large amount of this information is in the form of images, which shows the importance of image processing. due to the random physical nature of imaging systems, noise in the image is unavoidable This makes it difficult to perform various image processes such as segmentation, recognition and interpretation .Searching to remove noise from digital images is a challenge, In this research, a combined method for reconstructing texts in noise imaging using two P-Norm techniques and gradient technique is presented. The purpose of this article is to blur and unmute a noise image so that the amount of noise in the output image is minimized or completely noise-free. Because the PNorm method works very well in removing noise from images with high noise distribution. First, the P-Norm technique is performed on the photo to improve the image quality in the best possible way. The descending gradient algorithm is then used to re-filter to remove residual noise to ensure that any potential noise in the final image is removed. In the simulation, three images with text were used, which showed the results of this simulation The combination of these two methods effectively restores the lost quality of the images so that the full readability of the writings results.

Cloud computing is an innovative paradigm meeting the user's demand for accessing a shared source comprising adjustable computational sources, such as servers and applied programs. The aim of the research is to conduct a bibliometric study of the scientific productions on "health cloud". The present study, was conducted using a bibliometric method in 2019 on PubMed database. It was selected 491 research papers over the period 2009-2019 for analysis. Data analysis was performed using VOSviewer and Excel software. The findings revealed that the production of health cloud-focused papers over a decade, excluding those in 2017, had an upward trend. The US, India, and China were the most productive in this respect. Having presented 5 papers on cloud computing, Costa, Lee, were most productive. The greatest co-occurrence was that of the words cloud computing, Internet, electronic health records, computer security, information storage and retrieval, algorithms, confidentiality, male, delivery of health care, computer communication networks, medical informatics, mobile applications, data mining, and Health information exchange. The results of the present study indicate the leading status of the US in health cloud publications. In view of the recognition received for using cloud computing, the trend of the papers in the base was upward in nature. On analysis of the co-occurrence of words, the largest cluster was that of cloud computing with 6 items focused on.

With the development of information and communication technology, discussions such as cost reduction, efficiency and increasing speed have caused an increasing change in the world of the Internet. Cloud computing is a style of computer computing that provides IT-related capabilities to users as a service. This paper presents a dynamic hybrid method for resource allocation and load balancing in mobile cloud environments, First, clustered resources are assigned to each privileged resource and with each request, data matching is performed to select the best source as the final allocation. If more than one source is selected during the matching phase, the binary genetic is responsible for selecting the final source for the assignment. Also, if failure occurs and migration is required, there is no need to run from the beginning, And the second option is accepted if it is free and Migration occurs from the same ranking assigned to the destination allocation, which improves the time required. In this paper, a hybrid algorithm in the mobile resource scheduling process is introduced, which works to provide satisfactory results to users through custom ranking mechanism and It is able to reduce the scale of source scheduling and candidate selection results in real time. Finally, the simulation of the two basic factors of clustering equilibrium and performance improvement in the adaptation phase for the proposed method was concluded. The output accuracy of the proposed method has improved by 4.2% compared to the model using the decision support vector method.

Mobile case networks are an independent set of mobile nodes that communicate with each other via wireless communications and are a good solution for unpredictable events. These networks also have no specific infrastructure that operates mobile and autonomously and through radio waves which they are in touch with each other. Due to the variable number of nodes in the communication network between them are constantly changing, so the security of these networks is very important. In this article, we study different types of routing protocols, security problems in routing mobile case networks and different types of secure routing protocols along with its advantages and disadvantages, and with changes in SPR protocol, the problem of wormhole attacks using a new combination. We solve by the closed collars technique. In this way, by adding another technique as the status collar technique to the SPR protocol, which is based on the status of each packet based on security features and encryption information, packets exchanged along the way can be tracked and controlled. We also used the Diffie-Hellman algorithm to manage the key and increase the security of the proposed method, and finally we used MATLAB software to implement the proposed algorithm.