Informatica

Machine type communication (MTC) systems are a new paradigm in communication systems where machines talk to each other rather than humans. It is expected that more than twenty billion smart devices are deployed around the globe by 2020. The machines talk to each other and communicate with cloud based MTC servers to monitor and control everything around us. Such ubiquitous sensing and actuating require a communication infrastructure. Cellular networks due to their wide coverage are the best candidate for the communication infrastructure. The 3GPP LTE system is the future cellular network. Access class barring (ACB) is introduced by the standard as a solution to alleviate the congestion at the access layer. It works as a persistent probability for network access at the data link layer. In this paper, we consider an MTC system with several devices using LTE system as communication network. Based on the suggestions of the 3GPP standard, we consider uniform activation of devices within a long interval. This activation pattern results in Poisson arrival traffic in each random access channel. Using this arrival traffic pattern, we obtain the ACB factor which maximizes the throughput in the access link. This factor depends on the traffic parameters. Then, we propose a scheme to estimate the traffic parameters. At the end, we propose an algorithm which takes into account practical considerations. We validate our analytical models through extensive simulations.

Many papers exist on ordinary fuzzy control charts in literature in order to consider the vagueness and uncertainty in observation data. These are on both variable and attribute control charts. Several extensions of fuzzy sets have appeared in literature since ordinary fuzzy sets emerged. Type-2 fuzzy sets are one of these extensions. Type-2 fuzzy sets take into account the imprecision of membership functions in three dimensions. The aim of this paper is to develop interval type-2 fuzzy control charts for number of nonconformities, briefly c-control charts. In this paper, the theoretical structure of interval type-2 fuzzy c-control charts is proposed for the first time and the application is implemented in a food company.

Linguistic hesitant fuzzy sets (LHFSs) permit the decision maker to apply several linguistic terms with each having several membership degrees to denote his/her preference of one thing. This type of fuzzy sets can well address the qualitative and quantitative cognitions of the decision maker as well as reflect his/her hesitancy, uncertainty and inconsistency. This paper introduces a distance measure between any two LHFSs and then defines a correlation coefficient of LHFSs. Considering the application of LHFSs, the weighted distance measure and the weighted correlation coefficient of LHFSs are defined. To address the interactions between elements in a set, the Shapley weighted distance measure and the Shapley weighted correlation coefficient are presented. It is worth noting that when the elements are independent, they degenerate to the associated weighted distance measure and the weighted correlation coefficient, respectively. After that, their application to pattern recognition is studied. Furthermore, an approach to multi-attribute decision making under linguistic hesitant fuzzy environment is developed. Meanwhile, numerical examples are offered to show the concrete application of the developed procedure.

This paper studies the generic construction of certificate-based signature (CBS) from certificateless signature (CLS). This paper proposes a new generic conversion from CLS to CBS which is more intuitive, simpler, and provably secure without random oracles than the current one. To develop the security proof, we put forth one novel CLS security model which features a previously neglected but nontrivial attack and hence captures the CLS security notion more comprehensively. We show that many existing CLS schemes can be proved secure in the current model by slightly modifying its original security proof. Following this conversion, many provably secure CBS schemes can be constructed from the corresponding existing CLS schemes.

To provide better overall performance, identity (ID)-based signcryption (IBSC) has been constructed by combining ID-based signature (IBS) and ID-based encryption (IBE) in a secure manner. Undoubtedly, the IBSC fulfills the authentication and the confidentiality by signature and encryption, respectively. All the previously proposed IBSC schemes are inseparable in the sense that the two-layer sign-then-encrypt procedure must be performed only by the same entity. However, the entities, such as wireless sensors and smart cards, are resource-constrained and become time consuming in executing the two-layer sign-then-encrypt procedure. Nowadays, the usage of mobile cloud computing is gaining expanding interest which provides scalable and virtualized services over the Internet or wireless networks while users with resource-constrained devices can enjoy the advantages of mobile cloud computing environments. Hence, we aim to reduce the computational cost for resource-constrained devices by employing a third party. In this article, we present the first separable ID-based signcryption (SIBSC) scheme in which the signing and encrypting layers are performed by the device and a third party, respectively. Under the computation Diffie–Hellman (CDH) and bilinear Diffie–Hellman (BDH) assumptions, we demonstrate that the proposed SIBSC scheme offers the provable security of authentication and confidentiality while retaining communication performance.

The aim of this manuscript is to propose a new extension of the MULTIMOORA method adapted for usage with a neutrosophic set. By using single valued neutrosophic sets, the MULTIMOORA method can be more efficient for solving complex problems whose solving requires assessment and prediction, i.e. those problems associated with inaccurate and unreliable data. The suitability of the proposed approach is presented through an example.

A novel approach to pricing on data marketplaces is proposed, which is based on the Name Your Own Price (NYOP) principle: customers suggest their own price for a (relational) data product and in return receive a custom-tailored one. The result is a fair pricing scheme where sellers can achieve a higher revenue, while buyers receive a product which matches both their preferences and budget. NYOP is contrasted with previous research on view-based pricing on data marketplaces as well as on discount schemes to increase revenue.

Continuous query is a monitoring query issued by a moving object to keep the query condition satisfied. In the continuous query, the safe-region method is preferable to reduce the load for several requests on the server. A safe-region is a region in which the query result is unchanged, and it is created and sent to the moving object with the query result. The moving object always checks the current position in the region. When it leaves the region, it requests a new result to the server. Safe-region generation methods have been eagerly discussed for simple query types, including kNN, distance range, and RkNN queries. This paper challenges to generate the safe-region for trip route planning queries (TRPQ). This type of query is very time consuming even for snap-shot queries, and therefore, there are many restrictions on the safe-region generation methods in existing studies. This paper first investigates the property of the safe-region on TRPQ, and then proposes two types of efficient algorithms, the preceding rival addition (PRA) and the tardy rival addition (TRA) algorithms. The former algorithm runs fast, however, it still requires long processing time when the density of the data object is high. The latter algorithm is very fast independent of the density of data objects, however, the safe-region generated by TRA becomes about 5% larger in the size of generated safe-region. We evaluate the performance through intensive experiments.

Analysing massive amounts of data and extracting value from it has become key across different disciplines. As the amounts of data grow rapidly, current approaches for data analysis are no longer efficient. This is particularly true for clustering algorithms where distance calculations between pairs of points dominate overall time: the more data points are in the dataset, the bigger the share of time needed for distance calculations.

The redundancy allocation problem (RAP) has been studied for many different system structures, objective functions, and distribution assumptions. In this paper, we present a problem formulation and a solution methodology to maximize the system steady-state availability and minimize the system cost for the repairable series-parallel system designs. In the proposed approach, the components’ time-to-failure (TTF) and time-to-repair (TTR) can follow any distribution such as the Gamma, Normal, Weibull, etc. We estimate an approximation of the steady-state availability of each subsystem in the series-parallel system with an individual meta-model. Design of experiment (DOE), simulation and the stepwise regression are used to build these meta-models. Face centred design, which is a type of central composite design is used to design experiments. According to a max–min approach, obtained meta-models are utilized for modelling the problem alongside the cost function of the system. We use the augmented ε-constraint method to reformulate the problem and solve the model. An illustrative example which uses the Gamma distribution for TTF and TTR is explained to represent the performance of the proposed approach. The results of the example show that the proposed approach has a good performance to obtain Pareto (near-Pareto) optimal solutions (system configurations).