introduction: iran's social security organization provides hospital services through direct treatment system (hospitals owned by the organization) and indirect treatment system (purchasing of hospital services and other health care services from other providers). the current research aims to assess technical performance and determine the relationship between activity size and efficiency level o...

In this paper, the theory and modeling of large scale photovoltaic (PV) in the power grid and its effect on power system stability are studied. In this work, the basic module, small signal modeling and mathematical analysis of the large scale PV jointed multi-machine are demonstrated. The principal portion of the paper is to reduce the low frequency fluctuations by tuned stabilizer in the atten...

This paper discusses the relationships between computer mediated communications and other forms of communication and describes a particular computer conferencing system in use within IBM. The system described is quite large, with over three thousand contributors and over twenty thousand readers. We discuss the structure of the system, the actions that users can take, and the ways in which the s...

Cloud computing, one type of distributed systems, is becoming very popular. It has demonstrated easily processing very large data over commodity clusters is possible with correct programming model and infrastructure. One critical issue here lies in the file system (FS) [1]. In this report, I reviewed a number of outstanding distributed file systems (DFS).

The revolution of Internet and the Web takes the computer and information technology into a new age. The information on the web is growing very fast. The progress of information and communication technologies has made accessible a large amount of information, which have provided each of us with access to far more information than we can comprehend or manage. This emphasizes the difficulty with ...

The last few years have seen a steady rise in the occurrence and sophistication of distributed denial of service (DDoS) attacks. Volume-based attacks aggregate at a target’s access router, suggesting that (i) detection and mitigation is best done by providers in their networks; and (ii) attacks are most readily detectable at access routers, where their impact is strongest. In-network detection ...

This paper introduces a client/peer architecture providing services similar to Group Communication systems, but with the scalability of peer-to-peer systems and its dynamic behavior. We present Clippee, a first prototype of this client/peer architecture. Clippee employs a data replication scheme based on an optimistic use of locks, without running an expensive consensus protocol. We believe tha...

Tree boosting is an important type of machine learning algorithms that is widely used in practice. In this paper, we describe XGBoost, a reliable, distributed machine learning system to scale up tree boosting algorithms. The system is optimized for fast parallel tree construction, and designed to be fault tolerant under the distributed setting. XGBoost can handle tens of millions of samples on ...

This paper addresses a central challenge in PRISM, a large-scale distributed monitoring system: coping with the uncertainties and ambiguities introduced by network and node failures. In particular, in a large scale monitoring system, such failures interact badly with techniques needed for scalability like hierarchy, arithmetic filtering, and temporal batching. For example, if a monitoring subtr...