Institute of Electron Technology
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On the Design of the TCP/AQM Traffic Flow Control Mechanisms, Journal of Telecommunications and Information Technology, 2012, nr 4
Get PDFSeveral aspects of the TCP/AQM system design are discussed that may affect performance of the network. Namely, due to decentralized structure of the network traffic flow control system in which traffic rate control tasks are delegated to autonomous agents, it may be possible for the agents to profitably re-engineer the TCP congestion control algorithm at the cost of the overall performance of the network. In this paper it is shown how the commonly applied TCP/AQM design procedures may give rise to mechanisms that are prone to attacks discreetly moving the network traffic flow away from the desired operating point. Furthermore, a short discussion is presented concerning the countermeasures that can be taken to reduce these effects
Drive Encryption and Secure Login to a Secure Workstation for Special Applications, Journal of Telecommunications and Information Technology, 2012, nr 3
Get PDFWe discuss the problem of a secure login to a virtualized workstation. For increased security, the workstation’s hard drive is encrypted. During the startup, a decryption password to the drive must be entered by a user. We propose a solution that involves mutual authentication between the workstation and the user and ensures the password may be entered securely
Secure-Sim-G: Security-Aware Grid Simulator – Basic Concept and Structure, Journal of Telecommunications and Information Technology, 2012, nr 1
Get PDFTask scheduling and resource allocation are the key issues for computational grids. Distributed resources usually work at different autonomous domains with their own access and security policies that impact successful job executions across the domain boundaries. In this paper we present a security-aware grid simulator Secure-Sim-G, which facilitates the evaluation of the different scheduling heuristics under various scheduling criteria in several grid scenarios defined by the security conditions, grid size and system dynamics. The simulator allows the flexible activation or inactivation of all of the scheduling criteria and modules, which makes the application well adapted to the proper illustration of the different realistic scenarios and avoids the possible restriction to the specific scheduling resolution methods. The simulation results and traces may be graphically represented and stored at the server and can retrieved in different formats such as spreadsheets or pdf files
Design and Development of a UDP-Based Connection-Oriented Multi-Stream One-to-Many Communication Protocol, Journal of Telecommunications and Information Technology, 2012, nr 1
Get PDFA communication protocol is a set of rules defined formally that describes the format of digital messages and the rules for exchanging those messages in or between computing systems. The Internet Protocol Suite used for communications throughout the Internet uses encapsulation to provide a way of abstracting protocols and services. This abstraction is grouped into layers of general functionality. For protocols on the transmission layer, many choices exist. But while popular protocols such as TCP, UDP and SCTP do provide connection oriented communication offering reliability, ordering and data integrity, solutions that offer such connections from one point to multiple endpoints are still limited. TCP only supports point-to-point communication and SCTP offers multi-homing functionality, but the transmission is still limited to two logical endpoints. In this paper we use the simple, stateless, transmission model of UDP in order to provide TCP-like services for one-to-many communication that is not limited to just multi-homing or other particular solutions. The protocol supports reliable communication from one endpoint to multiple endpoints in different transmission modes. In order to make it easier for developers to customize the protocol to their needs and possibly extend/modify it in order to create new variants from it, the protocol is developed in user space. Because of this design restriction performance wasn’t the main objective of our work, but rather the ease of customization and experimentation with new protocol variants. The protocol was implemented in the C++ programming language using classes with virtual members. New variants of components, such as packet retransmission, can easily be implemented without changing the whole code base
Component-Based Architecture for Systems, Services and Data Integration in Support for Criminal Analysis, Journal of Telecommunications and Information Technology, 2012, nr 1
Get PDFCriminal analysis processes is based on heterogeneous data processing. To support it, analysts utilize a large set of specialized tools, however they are usually designed to solve a particular problem are often incompatible with other existing tools and systems. Therefore, to fully leverage the existing supporting tools, their technological integration is required. In this paper we present original approach for integrating systems based on the component-driven paradigm. Firstly, a problem of supporting criminal analysis is described with a strong emphasis on the heterogeneity issues. Secondly, some theoretical information about integration is depicted followed by the details of the proposed architecture. Finally, the technological assumptions are discussed and prototype integration based on proposed concept is overviewed. om the experiments are discussed in the final part of the paper
Interoperacyjność inteligentnych systemów transportowych. Telekomunikacja i Techniki Informacyjne, 2012, nr 1-2
Get PDFW artykule zaprezentowano wybrane zagadnienia interoperacyjności inteligentnych systemów transportowych (IST). W większości dotyczą one określenia interoperacyjności, aspektów komunikacyjnych w obszarach funkcjonalnych – podsystemach IST oraz europejskich i krajowych ram interoperacyjności
Modeling and Simulation of a Vehicle Suspension with Variable Damping versus the Excitation Frequency, Journal of Telecommunications and Information Technology, 2012, nr 1
Get PDFIn this work, three types of vehicle suspensions were considered and modeled as follows: oil damper mounted in parallel with a compression helical spring, for which a Kelvin-Voigt model, consisted of a dashpot and an elastic element connected in parallel is considered; colloidal damper without attached compression helical spring, for which a Maxwell model, consisted of a dashpot and an elastic element connected in series is considered; and colloidal damper mounted in parallel with a compression helical spring, for which a standard linear model, consisted of a Maxwell unit connected in parallel with an elastic element is considered. Firstly, the vibration transmissibility from the rough road to the vehicle’s body for all these suspensions was determined under the constraint that damping varies versus the excitation frequency. Then, the optimal damping and stiffness ratios were decided in order to minimize the transmissibility of vibration from the rough pavement to the vehicle’s body
The Application of Neural Networks to the Process of Gaining and Consolidating the Knowledge, Journal of Telecommunications and Information Technology, 2012, nr 1
Get PDFThe e-learning course is one of the most efficient and promising didactic policies. It must be grounded on the revision because it was proved that it enhances the long-term memory. However, human mind is not a uniform phenomenon. Each man memorizes and learns in a different manner. The purpose of the intelligent e-learning system presented in this paper is to teach orthography and this system is based on the multilayer neural network. Such structure enables a learner to adjust the crucial period between revisions to personal learning habits and policy
Model of User Access Contro to Virtual Machines Based on RT-Family Trust Management Language with Temporal Validity Constraints – Practical Application, Journal of Telecommunications and Information Technology, 2012, nr 3
Get PDFThe paper presents an application of an RT-family trust management language as a basis for an access control model. The discussion concerns a secure workstation running multiple virtual machines used to process sensitive information from multiple security domains, providing strict separation of the domains. The users may act in several different roles, with different access rights. The inference mechanisms of the language are used to translate credentials allowing users to access different functional domains, and assigning virtual machines to these domains into clear rules, regulating the rights of a particular user to a particular machine, taking into account different periods of validity of different credentials. The paper also describes a prototype implementation of the model