- Anonymous Stateless Communication Architecture: Design, Network Performance Analysis, and Integration of Tor Hidden Services for Privileged Communications
- Fairness-aware Joint Pattern and Power Design for Downlink PDMA Systems
- Hybrid Feature Selection Framework for Machine Learning-based Bot Detection on Social Media
- Evaluating AES Payload Encryption for Securing MQTT-based Smart Home Networks with Machine Learning-based Intrusion Detection
- Effects of Deformation of Main Reflector of Double Reflector Spherical Antenna on Its Aperture Field - ROT-54/2.6 Antenna Case
- Improving Performance of GNSS Acquisition Systems by Optimizing TM-CFAR Thresholds Using Metaheuristics
- Optimized Fuzzy Secure Scheme for Trust Assessment in IoMT
No. 4 (2012)
Published:
2012-12-30
ARTICLES FROM THIS ISSUE
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Multiple Criteria Evaluation and Ranking of Social Penetration of Information Society Technologies
Abstract
The paper presents a comparison of two ways of multiple criteria ranking of social penetration of information society technologies (ICT): the traditional one and the socalled objective ranking, illustrated on the example of Network Readiness Index. It is shown that objective ranking stresses a balanced development more than the traditional one. Another issue presented in this paper is the concept of dynamic ranking, a systematic presentation and prediction of the change of ranking in time. This is illustrated on the example of regions of three European countries: Finland, Italy and Poland.
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Who is Asking and for What: WHOIS Traffic Analysis
Abstract
The paper presents analysis of WHOIS requests for 13-month period. Both requestor address and the domain name being requested are analyzed, showing that WHOIS traffic can be roughly classified into systematic scanning of domain names and individual low-volume activity, mostly targeting very popular names. The comparison of requested names with standard dictionary entries reveals typical mutations for registered names, and mutations performed by scanning automata. As most popular names in WHOIS coincide with standard top website ranks, the ways of utilizing WHOIS data for the benefit of Internet community as a whole, are proposed.
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Competition and Diffusion of Telecommunication Services: The Multimedia Communication Services in Brazil
Abstract
This paper aims to discuss the recent trends in the regulation of telecom services regarding the diffusion of broadband. To this matter, it compares the recent international competition regulation experiences to the Brazilian scenario. Considering that the telecom sector passed through huge technological and structural transformations in the last decades (from typical voice communications to convergent services based on broadband, and from voice services monopoly to multiple services oligopoly), its regulatory framework has also changed. Lately, several countries – such as the United States, the Netherlands, Korea and Chile – have established inter and intra-platform competition regulations in order to expand the access to the new forms of communications based on broadband. In Brazil, such mechanisms are not fully explored, and the country has lots of areas in which there is no competition in broadband services (known as multimedia communication services). As a result, Brazil has one of the highest prices of broadband services and one of the lowest levels of broadband penetration. In this way and considering international success in expanding services through competition, the paper defends that such mechanisms should be reinforced in the Brazilian broadband market.
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On the Design of the TCP/AQM Traffic Flow Control Mechanisms
Abstract
Several 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.
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Low Complexity Greedy Power Allocation Algorithm for Proportional Resource Allocation in Multi-User OFDM Systems
Abstract
Multi-User Orthogonal Frequency Division Multiplexing (MU-OFDM) is an efficient technique for achieving high downlink capacity in high-speed communication systems. A key issue in MU-OFDM is the allocation of the OFDM subcarriers and power to users sharing the channel. In this paper a proportional rate-adaptive resource allocation algorithm for MU-OFDM is presented. Subcarrier and power allocation are carried out sequentially to reduce the complexity. The low complexity proportional subcarriers allocation is followed by Greedy Power Allocation (GPA) to solve the rate-adaptive resource allocation problem with proportional rate constraints for MU-OFDM systems. It improves the work of Wong et al. in this area by introducing an optimal GPA that achieves approximate rate proportionality, while maximizing the total sum-rate capacity of MU-OFDM. It is shown through simulation that the proposed GPA algorithm performs better than the algorithm of Wong et al., by achieving higher total capacities with the same computational complexity, especially, at larger number of users and roughly satisfying user rate proportionality.
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UML Simulation of a Topology Configuration Model
Abstract
The article presents the application of simulation methods for topological models to analyze and design information systems. By using UML extensions and the UAL language it is possible not only to build a topological model for software, but also to perform efficient simulations of topological models. Additionally, it is possible to take into account the restrictive conditions stored in UAL and OCL languages. To execute the simulation the authors used an simulator from IBM. These concepts and methods are illustrated by examples.
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Skill-Based Bimanual Manipulation Planning
Abstract
The paper focuses on specification and utilization of manipulation skills to facilitate programming of bimanual manipulation tasks. Manipulation skills are actions to reach predefined goals. They constitute an interface between low-level constraint-based task specification and high level symbolic task planning. The task of the robot can be decomposed into subtasks that can be resolved using manipulation skills. Rubik’s cube solving problem is presented as an example of a 3D manipulation task using two-arm robot system with diverse sensors such as vision, force/torque, tactile sensors.
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Optimizing the Structure of Vector Bend and Strain Sensor on the Base of Three-Core Microstructured Fiber
Abstract
In the paper the optical sensor allowing measuring a direction, values and localization of bends and stresses in building structures is described. The sensitive element of the sensor is the microstructured fiber with three cores. The use of three-core fiber makes it possible to define the direction of deformation. Distribution of mode fields in fiber cores depending on fiber structure and bend value and direction is analyzed. The optimization of the sensitive element parameters depending on the application is proposed.
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How the Role-Based Trust Management Can Be Applied to Wireless Sensor Networks
Abstract
Trust plays an important role in human life environments. That is why the researchers has been focusing on it for a long time. It allows us to delegate tasks and decisions to an appropriate person. In social sciences trust between humans was studied, but it also was analyzed in economic transactions. A lot of computer scientists from different areas, like security, semantic web, electronic commerce, social networks tried to transfer this concept to their domains. Trust is an essential factor in any kind of network, whether social or computer. Wireless sensor networks (WSN) are characterized by severely constrained resources, they have limited power supplies, low transmission bandwidth, small memory sizes and limited energy, therefore security techniques used in traditional wired networks cannot be adopted directly. Some effort has been expended in this fields, but the concept of trust is defined in slightly different ways by different researchers. In this paper we will show how the family of Role-based Trust management languages (RT) can be used in WSN. RT is used for representing security policies and credentials in decentralized, distributed access control systems. A credential provides information about the privileges of users and the security policies issued by one or more trusted authorities.
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Educating on Wireless Solutions for Environmental Monitoring
Abstract
Environmental monitoring is of growing interest around the globe and there is a clear need for better education in this area. However, the progress is incredibly fast here and wireless sensor networking is a relatively new area of research, so no standard curricula are available yet. In 2012, the International School “Sustainable Wireless ICT Solutions for Environmental Monitoring” was organized by the International Center for Theoretical Physics (ICTP) in collaboration with a few other entities. The school aimed at exposing young scientists from around the world to the newest wireless solutions for environmental monitoring. The school was followed by an awareness conference, which aimed at identifying issues that would benefit from a wider scientific collaboration. This paper begins with general information about the ICTP educational activities related to wireless technologies and applications. Then it focuses on the program of the school and conference. It shows what topics were included (and what were disregard) and what approaches were applied in order to achieve the best results with the (very) limited resources available. Details are omitted here as the complete materials of the both events are available at the Internet (http://wireless.ictp.it) under the Creative Commons.
