Informatica

To solve the problem of choosing the appropriate cloud computing vendors in small and medium-sized enterprises (SMEs), this paper boils it down to a group decision making (GDM) problem. To facilitate the judgment, this paper uses preference relation as the decision making technology. Considering the situation where uncertain positive and negative judgments exist simultaneously, interval-valued intuitionistic fuzzy preference relations (IVIFPRs) are employed to express the decision makers’ judgments. In view of the multiplicative consistency and consensus analysis, a new GDM algorithm with IVIFPRs is offered. To accomplish this goal, a new multiplicative consistency is first defined, which can avoid the limitations of the previous ones. Then, a programming model is built to check the consistency of IVIFPRs. To deal with incomplete IVIFPRs, two programming models are constructed to determine the missing values with the goal of maximizing the level of multiplicative consistency and minimizing the total uncertainty. To achieve the minimum adjustment of original preference information, a programming model is established to repair inconsistent IVIFPRs. In addition, programming models for getting the decision makers (DMs)’ weights and improving the consensus degree are offered. Finally, a practical decision making example is given to illustrate the effectiveness of the proposed method and to compare it with previous methods.

Generally, the task in a distributed system must achieve an agreement. It requires a set of processors to agree on a common value even if some components are corrupted. There are significant studies on this agreement problem in a regularized network environment, such as the Fully Connected, BroadCast and MultiCast Networks. Recently, many large complex networks have emerged and displayed a scale-free feature, which influences the system to reach a common value differently. Unfortunately, existing agreement protocols and results cannot cope with the new network environment and the agreement problem thus needs to be revisited. In this paper, we propose a new agreement protocol to adapt to the scale-free network environment and derive its bound of allowable faulty TMs with two rounds of message exchange. We have proved the correctness of this protocol and analyzed its complexity. It is observed that the scale-free network with the proposed agreement protocol can tolerate more faulty TMs than the networks based on previous studies.