فهرست مطالب eslam nazemi

NoSQL systems are suitable solutions for big data projects and offer a high level of flexibility in design. A good and efficient schema design for NoSQL wide column stores is not only based on the application’s conceptual data model but also on the queries defined in an application’s workload. In these databases, a manual schema design relies on rules of thumb to choose a good schema. Utility these rules without practices is a big challenge in this area. Because these rules are vague and generic, and must be adapted to each application. One of the ways that researchers use to overcome this challenge is presenting automated schema design. The main contribution of this paper is automated schema design for NoSQL wide column stores. This research proposes a workload-driven approach for the mapping from the application conceptual data model to a database schema with a goal of optimizing query performance. This approach uses workload information to achieve a good workload performance, which result in an optimized schema by minimizing the number of requests to the wide column stores. The experimental results show that automated schema generated by the proposed approach leads to a good workload performance.

Authorization systems are an important part of security systems that are responsible for protecting resources. With the increasing number of users in organizations, managing the authorization infrastructure has become increasingly time-consuming and error-prone and misconfiguration of policies has reduced the effectiveness of these systems. Researchers recommend dynamic access control methods as an effective way to issue licenses in these systems. Since the sources of decision making in these methods are the defined policies and user records, there are no special restrictions for new users and these methods face the problem of cold start. In this paper, to solve this limitation, the concepts of trust and I-sharing are used, and a new method for improving the Self-Aaptive Authorization Framework (SAAF) called ISAAF is presented. ISAAF is a framework for self-adaptive control of authorization systems using the MAPE-K autonomous reference model, which estimates the trust of new users using the trust of users with whom they have common features. I-sharing gr

Social media data is one of the most effective and accurate indicators of public sentiment, so that analyzing this information can provide researchers with interesting results from users' sentiment about characters, subjects, products, and services. In this study, while reviewing users' opinion on Twitter about the various features of two competing mobile phone products on the market, Apple's Iphone X and Samsung's Galaxy S9, we examine their sentiment based on the gender of consumers of these two products. This study is performed using the relation-based method in the feature extraction step and Lexicon-Based in the polarity of opinions step. The results of this study show that the popularity of different product features varies between male and female users, and based on these results, business owners can produce products that focus on people's gender or design smart advertising plan according to their interests. These measures ultimately lead to increased business profitability and customer satisfaction.

Today, with the rise of cloud data centers, power consumption has increased and cloud infrastructure management has become more complex. On the other hand, meeting the needs of cloud users is an important goal in cloud infrastructure. The process of determining the load status of physical machines and placing virtual machines on suitable physical machines can reduce energy consumption and prevent service level agreement violations. To address these issues, a virtual machine placement solution with a prediction capability is required to effectively place virtual machines in the proper hosts at runtime. The aim of this study is to provide a cloud management strategy that uses regression, moving average and simple exponential smoothing predictive models to identify overloaded physical machines and heuristic methods based on energy consumption, CPU utilization, number of virtual machines and memory to determine the appropriate physical machine for virtual machine placement, so provides a proper trade-off between reducing service level agreement violations and energy consumption and also decreases the number of virtual machine migrations. The cloudsim simulator version 3.0.3 has been used to evaluate the proposed model. The simulation results show that the proposed model averagely reduced the service level agreement violations by 45.65%, energy consumption by 28.96% and the number of virtual machine migrations by 46.49% compared to similar methods.

Nowadays, using Multi-Agent Systems (MASs) as a way of controlling complex and large-scale systems is becoming very popular. Also, since the scale of the systems is growing up and their environmental changes are becoming very fast and complicated, the experts are trying to enable these systems to control themselves, instead of having them controlled by humans. One way to devolve this responsibility to the systems is to use self-organization in MASs. To have a self-organizing MAS, agents should be able to shape up an organization. There are different organizational paradigms to be used in self-organizing MASs. Normally, the selection of organizational paradigm is done on design time by the designer of the system. But, in a rapidly changing and complicated environment, the selected paradigm might no longer be suitable for the system. In such a situation, there should be another way for the system to select a new suitable organizational paradigm at runtime. There are some works that provide a comparison among different organizational paradigms based on the performance of the MAS that uses that paradigm. But the comparison is done after the system is designed to have the paradigm. These works do not provide a mechanism for the system to select its paradigm at runtime. In this paper we propose an organization model for self-organizing MASs that provides these systems with the ability to change their organizational paradigm at run time. This organization model considers an amount of utility as the criterion based on which the currently used paradigm can be changed by the system itself. We simulate and evaluate our model in an IoT scenario. The scenario includes a Smart Home and its application of Comfort of Residences. The results show that changing the organizational paradigm and not sticking to the selected one on design time, gives us a 28% improvement on the utility.

Today, with the rise of cloud data centers, power consumption has increased and cloud infrastructure management has become more complex. On the other hand, meeting the needs of cloud users is an important goal in the cloud infrastructure. To solve such problems, an autonomous model with predictive capability is needed to do virtual machine consolidation at runtime effectively. In fact, using the feedback system of autonomous systems can make this process simpler and more optimized. The goal of this research is to propose a cloud resource management model that makes the virtual machine consolidation process autonomous, and by using a prediction method compromises between service level agreement violations and energy consumption reduction. In this research, an autonomous model is presented which detects overloaded servers in the analysis phase by a prediction algorithm. Also, at the planning phase, a multi heuristic algorithm based on learning automata is proposed to find proper servers for virtual machine placement. Cloudsim version 3.0.3 was used to evaluate the proposed model. The results show that the proposed model has reduced averagely the service level agreement violations, energy and migration counts by 67.08%, 11.61% and 70.64% respectively, compared to other methods.

So far, valuable researches have been conducted on mapping object-oriented specification notations, such as Object-Z, to different object-oriented programming languages, such as C++. However, the results of selecting JVM-based programming languages for mapping have not covered most of basic Object-Z structures. In this paper, the Groovy language, as a dynamic JVM-based language, is selected to overcome some of the existing limitations. As the main contribution, the rules required for mapping Object-Z specifications to executable Groovy code are introduced. The proposed rules cover notions such as multiple inheritance, inverse specification of functions, functions defined on generic definitions, and free type constructors. These notions have not been covered in previous methods for formal program development from object-oriented specifications, regardless of the selected formal specification language and target programming language. In addition, in this paper, the parallel composition construct is mapped to a parallel, executable code to improve the faithfulness of the final code to the initial specification. We also introduce a mapping rule for the class union construct, which has not yet been provided for any JVM-based language. Unlike previous works, instead of presenting the mapping rules in terms of natural languages, we present them in terms of some formal mapping rules.

One of the new effective technologies for healthcare is the use of wearable sensor technology in the environment of internet of things (IOT). In this article, we examined the activities of patients with stress and fatigue complaints as well as the effects of such devices on improving their general health.
In this survey study, General Health Questionnaire (GHQ) was used to assess the status of general health among the individuals in the selected sample in two stages of before and after the intervention; while the rate of changes in some of the measurable indicators was measured through wearable sensor devices during the study period. Given the existing limitations, 26 individuals were randomly selected, and finally 20 of them agreed to cooperate in this research. The obtained results were analyzed using descriptive statistics.
After a thirty-day trial, the overall general health which was initially at an average of 52%, improved after the intervention, reaching an average of 74% for the whole group. The results also showed the effect of increase in mobility rate on improving sleeping conditions, and depth of sleep among the participants.
A proper use of wearable sensor technology, to monitor the activities of individuals, and sending appropriate alert messages via the monitoring center, can improve their general health, reduce stress and fatigue, and modify health behaviors.

With the advancement of technology, many physical objects have been designed in a digital format such as books, tickets, and so on. In most cases, any virtual object can only be interpreted by a particular application software, so there will be a problem of interpretation. Virtual objects are a new set of objects in the cyber space and can do many things online and offline. Different research efforts have tried to provide a common structure for defining and managing virtual objects based on service-oriented architecture called device-dependent temporary services. In this paper, while defining a virtual object, it examines the features and benefits of the architecture of the device-dependent temporary services, and a method for implementing the virtual object of bus ticket as a case study based on it. The results show that the benefits of virtualization of bus tickets in the process of utilizing the relevant services have more value than other solutions.
Key words: Internet of Things, Virtual Object, Device-Dependent Temporary Services (DDTS), Bus Ticket.

Nowadays, using strategic alignment and IT governance can be an effective strategy to gain the initiative to help organizations allow efficient utilization of information technology and gain competitive advantage. The present article examines the gap between strategic alignment and IT governance maturity level of services in the field of virtual learning. To collect information and views of experts and thus to evaluate the alignment of IT and business on the field of virtual learning services, a questionnaire with 63 questions has been designed by integrating some expert-selected factors of Luftman and Cobit models.
Introduction While the study of strategic IT alignment has made significant progress in the last quarter century since the work of Henderson, Venkatraman, and others first emerged, there remains several important research questions that are still relatively unexplored. A lot can happen in 25 years. The fact that IT alignment is a perpetual priority for CIOs confirms that alignment is difficult but it also shows that alignment is a moving target. We see a continuing need for researchers to adapt and extend our knowledge of what it means for IT to be aligned with business. This will require fresh thinking as the extant IT alignment paradigms are a product of a simpler time when IT was less complicated and business strategy was more stable. To reflect the reality of IT and business strategy in modern society, a new approach is needed to account for the ways that businesses are increasingly attempting to exploit synergies between corporate, strategic business unit, and functional-level activity (Coltman et al., 2015).
Further investigation into IT governance structural relationship to IT strategic alignment may contribute to existing knowledge as well as add practical know-how to managers and executives planning and developing IT governance is an effort to achieve IT strategic alignment (Hosseinbeik et al., 2011).
In summary, the present research is aimed to find the answer for the following questions: What is the relationship between strategic alignment and IT governance structures in E-learning services? What are the effects of IT governance structures on e-learning services based on a combined selective strategic alignment model?
Case study Since the field of research is very large, and since the objective of this study is to provide a way to assess the relationship between alignment of IT and IT governance in the field of e-learning services, we selected virtual leaning department of Shahid Beheshti University as a case study in a specified range with similar characteristics with other universities.
E-learning domain has three key elements: Teacher, Student and expert personnel, so we asked our questions from these selected experts. The sample of 28 professors, experts, assistants, professors and graduate students (PhD) were asked to answer our questions as expert panel.
Materials and Methods This study is quantitatively trying to explore IT/business alignment and the gap between as-is status with to-be status of e-learning services at universities.
Conclusion Survey results indicate that proper use of information technology to successfully reach the goals with mean of 3.33 and design and implementation of appropriate basic systems with the mean of 3.16 show the most important influence, and in contrast failure to use an integrated enterprise architecture for virtual learning processes with the mean of 1.27, and lack of attention to risk factors of IT and non-implementation of a framework of internal control with the mean of 1.38, has been the most weakness factors. Thus, it is clear over and over that to promote strategic alignment and IT governance in virtual learning, require more effort in enterprise architecture and other areas that have low scores.

In the age of information and knowledge, the necessity of using virtual reality techniques for teaching nursing knowledge and skills, considering the sensitive tasks of nurses, is not hidden from anyone. Simulation-based educational software with high realism and quality are notable strategies to limit the risks of nursing education based on traditional method that can improve patient safety and reduce medical errors. The present study aimed at analyzing the role of models, approaches and learning theories in the design and production of educational software based on virtual reality techniques and simulation in nursing.
For the purpose of the present systematic review, all articles which were published from 2000 to 2015, which were related to educational software based on virtual reality in nursing both in English and Farsi were analyzed. To search for the study, databases such as SID, CINAHL, PubMed, Web of Science, EBSCO Host, Irandoc, Iranmedex, Google Scholar and relevant journals were used by using key words including education, nursing, theories of learning, software, simulation-based, computer-based, virtual reality techniques, models and their combinations. Several steps were taken for selecting and analyzing the full text of these studies. And, the articles which qualitatively met the inclusion criteria were assessed by using the relevant checklists.
Of the 850 articles that were related to the use of educational software based on virtual reality techniques and simulation in nursing, 12 articles which were directly related to the purpose of the study were chosen for further analysis. Of the 12 articles, four articles considered learning as a cognitive phenomenon. Five articles had used Jefferies simulation model and principles of learning theories.
The study concludes that the educational centers for training skilled nurses need the educational software based on virtual reality techniques as an educational tool, it seems necessary to direct the purposes of simulators toward learning based on professional competence paradigm with the use of simulation models and learning theories.

The main goal of this article is rating and scoring the importance of main elements over implementation of e-procurement in organizations (Case Study: Iranian Islamic Republic Railways). For Scoring and rating the elements, we used the statistical methods of Friedman test and Kruskal-Wallis test (test H), and Analysis Hierarchy Process (AHP). Here we used two methods to rate the elements over e-procurement adoption; The statistical processes and the AHP or Analytical Hierarchy Process. Also, in this study two kinds of questionnaire are used and designed, likert and AHP. Likert questionnaire is completed by 97 persons among Iranian Railways experts, managers and senior managers having BA 70% and MA, 19%. The statistical processes result showed that most effectiveness elements over e-procurement adoption in I.I.R.R are "Organization" as the first factor ranked score 4.0585, "Technology" as the second factor ranked score 3.7807 and "Environment" is the third factor ranked score 3.6968 respectively. AHP questionnaire is completed by 24 managers and senior managers of I.I.R.R and its results are similar to Fridman and Kruskal-Wallis "Organization" is the first ranked score 0.389, "Technology" is the second ranked 0.378 and "Environment" is the third factor ranked 0.233 which are the most important factors in e-procurement adoption in I.I.R.R respectively.

Due to the increasing web, there are many challenges to establish a general framework for data mining and retrieving structured data from the Web. Creating an ontology is a step towards solving this problem. The ontology raises the main entity and the concept of any data in data mining. In this paper, we tried to propose a method for applying the "meaning" of the search system, But the problem for these methods is building a knowledge base that can be used for semantic search. The previous work interprets the query in three ways:'semantic relation in ontology', 'co-occurrence in the document', and 'semantic relation from Thesaurus'. The proposed method has two parts. The first part, using domain ontology for classified web pages based on keyword and the concept in each domain and builds Fuzzy ontology as Knowledge Base and the next section offers a method for expanding the query using built fuzzy ontology. In this paper, we tried to create knowledge base with WordNet as a comprehensive dictionary and extracted Sub string (phrases include multi words) from WordNet for each keyword in each domain ontology. The created Search engine was applied to an experimental system to evaluate the "precision – Recall” and it was revealed that applying the proposed method can improve query expansion 11%better in our experiments for  precision.

Industrial organizations are complex systems` where the interactions among the various functions such as Sales, Distribution, Manufacturing, Materials, Finance, Human Resources and Maintenance have to be man-aged towards a common purpose of delivering the customers satisfaction. However, since most of these or-ganizations have a `Functional Structure`, each function or department works towards their own goals and ob-jectives, rather than the organizational goals. This is further aggravated because information flow is restricted by functions, and even when other functions want to take a holistic view, they do not have the information to do so. These are the issues addressed by Enterprise Resource Planning solutions providing a common, con-sistent system to capture data organization wide, with minimum redundancy. ERP integrates the resources such as information across functions, and provides a set of tools for planning and monitoring the various functions and processes and ensuring progress towards a common purpose in direction of goals and strate-gies. In this paper, we introduce a model for performance measurement of an organization, which they are working in competitive, monopoly or attractive business environment, and have total system or use ERP so-lution. We developed a Performance Measurement system that based on organization`s strategic and goals. In the following sections, we describe a brief survey of performance models. Then, we focused on per-formance measurement process, developing performance indicators and metrics. Our approach is to develop a process and a model for performance measurement by assigning priorities to all goals with respect to or-ganization strategies in specific business condition. The observation of using this model shows that it works very close to real world behaviors and can help senior managers for intelligent decision-making.

Presently, the need for developing software addressing shifting needs, rapid analysis, easy risk management and adaptability to changing environment, has turned into an irrefutable principle. Initial comprehensive planning and pre-production heavy design which are common to heavy-load methods can no longer respond to such needs. The high volume of documentations generated in these methods, could increasingly reduce the pace of system development. For reasons stated, innovative techniques for software development becomes imperative. In recent years, new methods based on the needs stated have been developed. These methods are known as light-weight methods. These methods in addition of expediting software analysis and development stages, can concurrently adapt the project with new changes and needs during the production process. Due to the absence of any clear-cut frame-work for software development using light-weight methods, it is a difficult task to evaluate and adopt any particular method based on project attributes. Following a comprehensive analysis of rapid methods and review of strengths and weaknesses of each, the present paper provides a comprehensive comparison based on 16 main criteria. Therefore, it makes it easy to choose an appropriate method based on special requirements of a given project.