Informatica

In this paper, one method for training the Support Vector Regression (SVR) machine in the complex data field is presented, which takes into account all the information of both the real and imaginary parts simultaneously. Comparing to the existing methods, it not only considers the geometric information of the complex-valued data, but also can be trained with the same amount of computation as the original SVR in the real data field. The accuracy of the proposed method is analysed by the simulation experiments. This also can be applied to the field of anti-interference for satellite navigation successfully, which shows its effectiveness in practical application.

World has become a global village after introduction of social media and social networks. However, it extensively increased the demand for network resources, particularly multimedia traffic like images, videos and audio. The medium for this extensive traffic is always public networks such as internet or cellular networks. But the open nature of such network like internet always creates security threats for data during transmission. Due to many intrinsic features and higher correlation in multimedia traffic, existing encryption algorithms are not very convincing to perform well under critical scenarios. Therefore, many people in the research community are still working to propose new encryption schemes which can address these issues and handle multimedia traffic effectively on public networks. In this paper, we explore the weaknesses of existing encryption schemes, which compromise in many scenarios due to high correlation of multimedia traffic. To tackle this issue we proposed certain enhancements in an existing scheme. Our enhanced modification includes addition of bitwise XORed operation using non-linear chaotic algorithm. Performance of enhanced scheme is tested against state of the art security parameters. Efficiency of the proposed scheme is also validated via entropy, correlation, peak signal to noise ratio, unified average change intensity and number of pixels change rate tests.

Fuzzy sets can be used in many old-fashioned aspects of our lives in order to reach better performance and make fairer judgments. Evaluation through examination is typically conducted by educational centers, and multiple choice question (MCQ) exams are widely applied to score the examinees. Since scoring is potentially a difficult process to judge, we propose to evaluate examinees by fuzzy evaluation method. This method can overcome the main shortcoming of the classical MCQs, i.e. the random selection of the choices. The evaluation of the proposed fuzzy MCQ is more accurate and its ranking of examinees is fairer than classical MCQ.

This paper presents a column generation-based modelling and solution approach for a teaching assistant workload scheduling problem that arises at academic institutions. A typical weekly workload schedule involves teaching deficiency classes, instructing problem-solving tutorial sessions, and allocating help-hours for students. For this purpose, a mixed-integer programming model that selects valid combinations of weekly schedules from the set of all feasible schedules is formulated. Due to the overwhelming number of variables in this model, an effective column generation procedure is developed. To illustrate the proof-of-concept along with modelling and algorithmic constructs, a case study related to the Department of Mathematics at Kuwait University is addressed. Computational results based on real data indicate that the generated schedules using the proposed model and solution procedure yield improved weekly workloads for teaching assistants in terms of fairness, and achieve enhanced satisfaction levels among assistants, as compared to schedules obtained using ad-hoc manual approaches.

The purpose of this study is to develop a hesitant trapezoidal fuzzy TODIM (interactive and multi-criteria decision making) with a closeness index-based ranking method to handle hesitant qualitative group decision making problems. First, a novel closeness index-based ranking method is presented to compare the magnitude of hesitant trapezoidal fuzzy numbers (HTrFNs). Based on the developed ranking method, the dominance values of alternatives over others for each expert are calculated. Then, a nonlinear programming model is established to derive the dominance values of alternatives over others for the group and correspondingly the optimal ranking order of alternatives is obtained.

In this paper, we presented another form of eight similarity measures between PFSs based on the cosine function between PFSs by considering the degree of positive membership, degree of neutral membership, degree of negative membership and degree of refusal membership in PFSs. Then, we applied these weighted cosine function similarity measures between PFSs to strategic decision making. Finally, an illustrative example for selecting the optimal production strategy is given to demonstrate the efficiency of the similarity measures for strategic decision making problem.

Business Process Model and Notation (BPMN) is the leading visual notation used for modelling business processes. This paper shows how the Alvis modelling language can be used for formal analysis of BPMN models. Alvis supports graphical modelling of interconnections among subsystems called agents as well as a high-level programming specification for describing the agents’ behaviour. Its advantage is the possibility of formal verification using proven model checking techniques. We propose a translation from the BPMN model to the Alvis representation, which is discussed and evaluated using an illustrative example of a process for evaluation of a student assignment. Thanks to the translation it is possible to perform formal verification of a BPMN model in a high-level concurrent environment. As opposed to some low-level representations, such as Petri nets, semantics of Alvis is close to the original BPMN model. Moreover, if a concurrent system behaviour is specified using a BPMN model, it is possible to generate a formal model (a preliminary implementation) of the system.

In this paper we consider an improved version of earlier published asymmetric encryption protocol based on matrix power function (MPF). Recently, a linear algebra attack on earlier version of this protocol was found. This attack allows an attacker to break suggested protocol in polynomial time.

Medical X-ray images are prevalent and are the least expensive diagnostic imaging method available widely. The handling of film processing and digitization introduces noise in X-ray images and suppressing such noise is an important step in medical image analysis. In this work, we use an adaptive total variation regularization method for removing quantum noise from X-ray images. By utilizing an edge indicator measure along with the well-known edge preserving total variation regularization, we obtain noise removal without losing salient features. Experimental results on different X-ray images indicate the promise of our approach. Synthetic examples are given to compare the performance of our scheme with traditional total variation and anisotropic diffusion methods from the literature. Overall, our proposed approach obtains better results in terms of visual appearance as well as with respect to different error metrics and structural similarity.

Strategic management is a process of determining a business long-term objectives and the way to achieve these goals. Considering importance of strategic planning in long-term competitive power of organizations, different frameworks are proposed to formulate strategies. How to choose the best strategy is a challenging activity due to its multi criteria nature and lack of information. In this paper, a method comprised of grey DEMATEL – grey analytic network process is proposed to deal with this challenge. The proposed method considered interrelationship among factors using DEMATEL and then these relations are applied in strategy ranking by ANP. The uncertainty and lack of information is handled using grey numbers. Application of the proposed method is illustrated in an ecotourism company.