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Group communications are significant applications of many emerging communication technologies. To preserve users' privacy in group communications, key agreement protocols with security and high efficiency are imperative. In this paper, a group key agreement protocol is presented to achieve this goal. The periodic array is originally applied to the group key agreement protocol to derive a session key by group members. Moreover, user authentication is supported in the proposed protocol to ensure secure group communications. Finally, the performance evaluation shows that the proposed protocol has both of the low communication complexity and the low computational complexity, indicating that the proposed protocol is efficient in group communications.

As medical devices have excellent resolutions and have become better connected to the Internet, doctors and patients are beginning to expect medical images to be available on mobile device for making a diagnosis or consultative viewing. However, the performance of querying and accessing medical images in anytime and anywhere using mobile device is still an issue. In this paper, we implement an medical image visualization system to efficiently query and access medical images by using smartphone, which has the following new features: 1) an on-demand data transmission method is implemented using DICOM web service, and only the required meta data and image region or series are transmitted to mobile device; 2) a high performance cache component is designed to cache the recently requested images, which takes up less storage and obtains higher performance; 3) a convenient way is introduced to quickly obtain a specific patient's studies by scanning a patient's barcode or quick response code. The performance and stability of our proposed method as well as the prototype system is evaluated with real DICOM data sets. The results show that our app obtains high performance and stability in both Wi-Fi and 4G mobile network, which is expected to be an effective tool for mobile telemedicine.

To improve the accuracy of clothing segmentation, a novel co-segmentation method is proposed in this paper based on HOG(Histogram of Oriented Gradients) features and E-SVM(Exemplar Support Vector Machine) classifier. The cosegmentation method uses an auxiliary dataset and is implemented with three steps: superpixel grouping, E-SVM classifier training, and segmentation propagation. Firstly, image input by user is segmented in superpixel, such that the images in auxiliary dataset can be divided into multi-regions. Secondly, some regions are selected to a positive segmentation and HOG information is used to train E-SVM classifiers. Finally, the cloth is segmented into user image with E-SVM classifiers and segmentation propagation. Experimental results show that the proposed method can segment clothing images with high accuracy.

Nowadays, there are a large number of online services in the open network environment. Due to the difference of subjective wills of users, such as consumption psychology and interests, their service preferences and evaluation standards differ. Since services are evaluated by users of inconsistent evaluation criteria, the scores would be possibly different even if the services same and that further led to online services not comparative. After exploring the way to provide highly satisfactory high-quality online services for users, a method is proposed in this paper for decision analysis. The method based on basic ideas of social choice theory, and according to information on each user's preferences and evaluation to build the user preference matrix at first. Then, 0–1 integer programming models are built for Kemeny social choice functions through the matrixes. Finally, the optimal ranking of services is obtained by solving the models, so that it may be consistent with group preferences to the greatest extent. The experimental results show that the proposed method not only effective for solving problems concerning incomparability of online services, but also efficiently resists recommendation attacks and manipulation.

Competition results are traditionally decided based on referees' rating scores. However, due to the inconsistent evaluation standard and the different subjective wishes of referees, the evaluation results will be affected to some extent. Thus, the objectivity of competition results will be reduced. We propose a method by using referees' preference ordering for players instead of traditional scores to evaluate the competition result. We constructs a relationship of referees' preferences for players and calculates players' overall ranking based on social choice theory and group decision. By constructing a directed graph and calculating the value of strongest path, we can improve the objectivity of result evaluation and the difficulty of manipulating competition results. We proved that the proposed method satisfies the criteria of fairness, consistency, maneuverability and monotonicity. Competition results will not be changed due to individual referees' preferences, so we can obtain a more reasonable result. We make a theoretical analysis and a comprehensive experimental study using real datasets to verify the rationality and effectiveness of the proposed method.

According to the terrain features of the tailings dam, the water boundary image of the tailings dam is obtained by the acquisition of the water. The contour recognition, threshold segmentation, and watershed algorithm can be used to retrieve the boundary between dry beaches and water surface. Analyze and deal with the image pixel coordinates, the most accurate pixel coordinates of waterline can be real-time measured. According to the terrain characteristics of tailings pond, through camera monocular visual to calculate the waterline pixel coordinates and the actual length of beach geometric conversion formula, and real-time monitoring of dry beach length. Based on monocular vision with the fixed dry beach slope, the algorithm is proved to meet the requirements of dry beach length measurement.

Open and dynamic environments lead to inherent uncertainty of Web service QoS (Quality of Service). Thus, the Web service composition which consists of these services will be necessarily random of the QoS. The requirements of the QoS of Web service composition may not be certainly satisfied. We use a simulation approach named Importance Sampling to analyze the QoS probability of Web service composition in stochastic PERT network. In this paper, we propose a relatively simple distribution function and introduce a weighting function to ensure that the estimating of the target distribution function is an unbiased estimation. We conduct a comparison of Importance Sampling technique with Monte Carlo simulation about the rationality and the operation efficiency based on the actual QoS data of Web services by experiment. The experimental results prove that the Importance Sampling technique has better precision and higher efficiency than Monte Carlo simulation.

Community of Web Service is a society composed by a number of functionally identical Web Services. The communities are regarded as a whole for users in an opening environment and users would pay for services when they invoke Web Service successfully. Communities should distribute the whole profit to all of the providers of Web Services inside after a settlement period. Due to the cooperation among Web Services in a community we treat these Web Services as a cooperative game. In this paper we propose a method to distribute profit based on Shapley value which considers the contribution of each Web Service to community and we then implement an algorithm based on MC-nets to suit the actual situation which we always cannot get complete input for general algorithm of computing Shapley value. We also show our method is efficient and practicable.

In this paper, we developed an extensible HL7 middleware to exchange the heterogeneous healthcare information. A semantic structure mapping, which can be configured dynamically, is presented to guide the data conversion of heterogeneous healthcare information. These heterogeneous data can be quickly built or parsed into standard HL7 messages for transmission. This middleware is designed and implemented based on the interface-oriented programming ideas and plug-in mechanism, which can be extended conveniently to accomplish the data exchange between new data format and the existing data format. Experimental results show that the heterogeneous healthcare information can be exchanged and integrated successfully and quickly using this HL7 middleware.