Ewa Niewiadomska-Szynkiewicz

Optimization Schemes For Wireless Sensor Network Localization

Optimization Schemes For Wireless Sensor Network Localization Many applications of wireless sensor networks (WSN) require information about the geographical location of each sensor node. Self-organization and localization capabilities are one of the most important requirements in sensor networks. This paper provides an overview of centralized distance-based algorithms for estimating the positions of nodes in a sensor network. We discuss and compare three approaches: semidefinite programming, simulated annealing and two-phase stochastic optimization—a hybrid scheme that we have proposed. We analyze the properties of all listed methods and report the results of numerical tests. Particular attention is paid to our technique—the two-phase method—that uses a combination of trilateration, and stochastic optimization for performing sensor localization. We describe its performance in the case of centralized and distributed implementations.

Predictive Methods for Real-Time Control of Flood Operation of a Multireservoir System: Methodology and Comparative Study

Predictive methods for real-time flood operation of water systems consisting of reservoirs located in parallel on tributaries to the main river are presented and discussed. The aspect of conflicting individual goals of the local decision units and other objectives important from an overall point of view is taken into account. The particular attention is focused on hierarchical control structure which provides framework for organization of an on-line reservoir management problem. The important factor involved in flood control the uncertainty with respect to future inflows is taken into consideration. A case study of the upper Vistula river basin system in the southern part of Poland is presented. Simulation results based on 11 historical floods are briefly described and discussed.

Security, energy, and performance-aware resource allocation mechanisms for computational grids

Distributed Cyber Physical Systems (DCPSs) are networks of computing systems that utilize information from their physical surroundings to provide important services, such as smart health, energy efficient grid and cloud computing, and smart security-aware grids. Ensuring the energy efficiency, thermal safety, and long term uninterrupted computing operation increases the scalability and sustainability of these infrastructures. Achieving this goal often requires researchers to harness an understanding of the interactions between the computing equipment and its physical surroundings. Modeling these interactions can be computationally challenging with the resources on hand and the operating requirements of such systems. In this paper, we define the independent batch scheduling in Computational Grid (CG) as a three-objective global optimization problem with makespan, flowtime and energy consumption as the main scheduling criteria minimized according to different security constraints. We use the Dynamic Voltage Scaling (DVS) methodology for reducing the cumulative power energy utilized by the system resources. We develop six genetic-based single- and multi-population meta-heuristics for solving the considered optimization problem. The effectiveness of these algorithms has been empirically justified in two different grid architectural scenarios in static and dynamic modes.

Localization in wireless sensor networks

Localization in wireless sensor networks: Classification and evaluation of techniques Recent advances in technology have enabled the development of low cost, low power and multi functional wireless sensing devices. These devices are networked through setting up a Wireless Sensor Network (WSN). Sensors that form a WSN are expected to be remotely deployed in large numbers and to self-organize to perform distributed sensing and acting tasks. WSNs are growing rapidly in both size and complexity, and it is becoming increasingly difficult to develop and investigate such large and complex systems. In this paper we provide a brief introduction to WSN applications, i.e., properties, limitations and basic issues related to WSN design and development. We focus on an important aspect of the design: accurate localization of devices that form the network. The paper presents an overview of localization strategies and attempts to classify different techniques. A set of properties by which localization systems are evaluated are examined. We then describe a number of existing localization systems, and discuss the results of performance evaluation of some of them through simulation and experiments using a testbed implementation.

Control system for reducing energy consumption in backbone computer network

SUMMARY Network optimization concerned with operational traffic management in existing data networks is typically oriented towards either maximizing throughput in congested networks while providing for adequate transmission quality, or towards balancing the traffic so as to maintain possibly large free capacity for carrying additional (new) traffic. Nowadays, the reduction of power consumption is a new key aspect in the development of modern wired networks. Power management capabilities allow modulating the energy consumption of devices that form a network by putting them into standby state, or by decreasing their performance in case of low incoming traffic volume. This paper presents a framework for backbone network management, which leads to the minimization of the energy used by this network. The policy for dynamic power management of the whole network through energy-aware routing, traffic engineering, and network equipment activity control is introduced and discussed. The concept of the system is to achieve the desired trade-off between total power consumption and the network performance according to the current load, incoming traffic, and user requirements. The effectiveness of our framework is illustrated by means of a numerical study. Copyright

A hybrid analytic/rule-based approach to reservoir system management during flood

The article presents an approach to real-time operation of a water retention reservoir during flood. Water releases are calculated repetitively on the basis of two-variant inflow forecasts and some expert knowledge. During every intervention of the control algorithm, an optimization problem with the expected value type performance index is solved. In the paper, the basic characteristics of trajectories of outflows resulting from the application of this control method are analyzed. Afterwards, the results of the series of simulation experiments based on a large set of historical data concerning a big Polish reservoir are presented.

Two-Phase Stochastic Optimization to Sensor Network Localization

In this paper we describe a novel approach to sensor network localization, i.e., two-phase algorithms based on simulated annealing and genetic algorithm. The numerical results presented and discussed in the final part of the paper show that these novel schemes give accurate and consistent location estimates of the nodes in the network. The performance is better and speed is faster than that of the semidefinite programming (SDP) and one-phase simulated annealing (SA).

Control system for reducing energy consumption in backbone computer network: CONTROL SYSTEM FOR REDUCING ENERGY CONSUMPTION IN BACKBONE NETWORK

Network optimization concerned with operational traffic management in existing data networks is typically oriented towards either maximizing throughput in congested networks while providing for adequate transmission quality, or towards balancing the traffic so as to maintain possibly large free capacity for carrying additional (new) traffic. Nowadays, the reduction of power consumption is a new key aspect in the development of modern wired networks. Power management capabilities allow modulating the energy consumption of devices that form a network by putting them into standby state, or by decreasing their performance in case of low incoming traffic volume. This paper presents a framework for backbone network management, which leads to the minimization of the energy used by this network. The policy for dynamic power management of the whole network through energy‐aware routing, traffic engineering, and network equipment activity control is introduced and discussed. The concept of the system is to achieve the desired trade‐off between total power consumption and the network performance according to the current load, incoming traffic, and user requirements. The effectiveness of our framework is illustrated by means of a numerical study. Copyright

Reconstruction of a social network graph from incomplete call detail records

Real-life call detail data (CDR) are used to build a graph of a social network of telecommunication operator customers. Affiliation network is used in graph construction since CDR data are partially kept anonymous. A number of the resulting network properties are examined to prove the correctness of the graph construction algorithm. Cliques in the network and network dynamics are analyzed; suggestions are given about possible utilization of the obtained information in the operation of a telecommunication operator.

Modeling Mobility in Cooperative Ad Hoc Networks

This paper addresses issues concerned with design and managing of mobile ad hoc networks. We focus on self-organizing, cooperative and coherent networks that enable a continuous communication with a central decision unit and adopt to changes in an unknown environment to achieve a given goal. In general, it is very difficult to model a motion of nodes of a real-life ad hoc network. However, mobility modeling is a critical element that has great influence on the performance characteristics of a cooperative system. In this paper we investigate a novel approach to cooperative and fully connected networks design. We present an algorithm for efficient calculating of motion trajectories of wireless devices. Our computing scheme adopts two techniques, the concept of an artificial potential field and the concept of a particle-based mobility. The utility and efficiency of the proposed approach has been justified through simulation experiments. The results of presented case studies show a wide range of applications of our method starting from simple to more complex ad hoc networks.