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Mobile ad hoc networks have different characteristics from wired networks. There are new challenges related to security issues that need to be addressed. In this paper, first, critical nodes and authentication in mobile ad hoc networks are discussed. Then, a monitoring nodes selection method with high battery power in these networks is presented. We propose a three-phase detection scheme. In the first phase, unauthorized nodes and in the second phase, malicious nodes are detected. Finally in the third phase, nodes with the largest battery power as monitoring nodes are considered. In the first and the second phases, detection scheme uses non-interactive zero knowledge technique in order to... 

Intrusion Detection Systems (IDS) for Mobile Ad hoc NETworks (MANETs) are necessary when they are deployed in reality. In This paper, we have presented a combined method of selecting IDS agent nodes in mobile ad hoc networks. Since, the IDS agents in MANET due to more activities need to more battery power. In our method, first, compromised nodes are detected and then the nodes with the highest energy power from among valid nodes as IDS agent nodes are considered. So, with this method, some valid nodes contribute in intrusion detection activities and costs of the network monitoring will be reduced and the network lifetime will be increased. © 2009 IEEE  

Mobile Ad hoc NETworks (MANET) due to different characteristics from wired networks are more vulnerable to security attacks. Construction of Intrusion Detection Systems (IDS) for MANETs is complicated by the fact that they are lack of fixed infrastructure and lack of central management for authentication and distribution of cryptographic keys. On the other hand, the network lifetime is an important issue in MANETs because of the energy power of mobile nodes is limited. In this paper is presented a proposed Method that in the first step, authorized nodes are detected by non-interactive zero knowledge technique and in the second step, nodes with the highest battery power from among authorized... 

The current paper focuses on the non-linear torsional vibration of a one-stage transmission gear system. Four different methods have been applied for solution of the equation of motion; the discretization method, the perturbation method, the Ritz method, and the stepwise time integration of the equation of motion. The time and frequency results from these analyses have been compared with each other, as well as those reported in literatures. Although all of these methods are accurate and computationally effective for finding the main spectral contribution, however, only the discretization method and the step-wise time-integration model are able to identify the other frequency components. ©... 

XML has emerged as a common standard for data exchange over the World Wide Web. One way to manage XML data is to use the power of relational databases for storing and querying them. So the hierarchical XML data should be mapped into flat relational structure. In this paper we propose an algorithm which maps DTD to relational schema and as well as content and structure it preserves the functional dependencies during the mapping process in order to produce relations with less redundancy. This is done by categorizing functional dependencies and introducing four rules to be applied to the relations created by the hybrid inlining algorithm according to each category. These rules will reduce... 

In this paper an analytical model is proposed to study the nonlinear dynamic behavior of rolling element bearing systems including surface defects. Various surface defects due to local imperfections on raceways and rolling elements are introduced to the proposed model. The contact force of each rolling element described according to nonlinear Hertzian contact deformation and the effect of internal radial clearance has been taken into account. Mathematical expressions were derived for inner race, outer race and rolling element local defects. To overcome the strong nonlinearity of the governing equations of motion, a modified Newmark time integration technique was used to solve the equations... 

In the present study, numerical simulations are conducted to estimate the in-plane response of adobe walls subjected to pseudo-static cyclic loading based on the finite element code ABAQUS. The simplified micro-modeling approach is adopted and an interface model reported in ABAQUS material library is applied as material model for zero-thickness interface elements. The comparison between obtained results and field test data results in good agreement. Parametric studies are carried out to evaluate the effectiveness of independent parameters changes on response of adobe walls. It is noted that mechanical properties of joints and adobe units play an active role on in-plane behavior of walls. A... 

Recently XML has become a standard for data representation and the preferred method of encoding structured data for exchange over the Internet. Moreover it is frequently used as a logical format to store structured and semi-structured data in databases. We propose a model-driven and configurable approach for modeling hierarchical XML data using object role modeling (ORM) as a flat conceptual model. First a non-hierarchical conceptual schema of the problem domain is built using ORM and then different hierarchical views of the conceptual schema or parts of it are specified by the designer using transformation rules. A hierarchical modeling notation called H-ORM is proposed to show these... 

Abstract ORM (Object Role Modeling) is a rich and popular conceptual modeling method. ORM has been used for data modeling, ontology engineering, modeling business rules, XML-Schemes and data warehouses, requirements engineering and web forms. Automated reasoning like satisfiability testing allows developers to detect modeling mistakes in the early stages of development. In this paper we propose a lightweight formalization of the ORM meta-model in Alloy. Using this meta-model as a toolkit one can easily specify ORM models in Alloy and verify various properties on them using the Alloy Analyzer. In order to achieve scalability, we use the cardinality of concepts to model their population. This... 

XML has become the preferred format for representing and exchanging structured and semi-structured data on the web. The XML Schema language is widely used for defining and validating highly structured XML instance documents. While text-based languages, such as XML-Schema, offer great advantages for data interchange on the Internet, graphical modeling languages are widely accepted as a more visually effective means of specifying and communicating data requirements for a human audience. This paper uses Object-Relationship-Attribute model (ORA-SS) as a conceptual graphical model for designing XML-Schemas. To facilitate this process we introduce an xml representation for ORA-SS Schema Diagram... 

In this paper we present a formal definition of the basic concepts and notations of Object Role Modeling (ORM) using the Z formal specification language. Most of ORM concepts such as object and relationship types, value types, objectification, reference schemes, sub-types, roles and constraints such as uniqueness, mandatory, cardinality, subset, equality, exclusive and ring constraints are specified formally. Population is specified as objects, relationships and roles instances. These are specified using Z axioms and diagram instances are specified using Z schemas. This would enable validation and reasoning on the formal properties of ORM diagrams such as detecting constraint contradictions... 

A novel intelligent semi-active control system for an eleven degrees of freedom passenger car's suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network... 

Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the...