###### Synergistic Network Connectivity among Urban Areas Based on Non-Linear Model of Housing Prices Dynamics

## Abstract

The assumption of a strong positive relationship between the specificity of an urban area and the operation of the housing market, which responds to megatrends in the market environment, has been the foundation of the research concept adopted for this study. The study treats the housing markets as complex, adaptive dynamic systems which develop through synergistic network responses. This paper employs a nonlinear critically-damped harmonic oscillator model and phase diagrams to describe the dynamics of housing prices (in the years 2006-2016) in order to demonstrate the synergistic network connections in selected Polish cities. In another important part of the study, the authors propose to employ non-classical dynamic measures, i.e. the absolute time of delay, relaxation time and a long-term level of equilibrium. The study has shown that network connections are strongly synchronized during periods of housing market instability (2006-2007), whereas the process of unsynchronization is observed during a period of stability (2008-2016). Moreover, phase diagrams have been used to demonstrate the similarity of trends in housing prices as well as the shapes of individual trajectories and the existence of multiple points of quasi-equilibrium.

###### Development of a Pressure Measuring Unit Based on a Thermal Conductivity Gauge and a Low-Cost Embedded Solution for Mid-Range Vacuum Applications

## Abstract

This study presents the development of a pressure measuring unit based on a Pirani gauge and a dedicated embedded system, incorporating a simple, low-cost practical solution for significantly reducing the various measurement altering factors, such as drifts, offsets and set point drifts. This is achieved by eliminating the conventional differential analogue signal processing stage and replacing it with a high resolution analog to digital converter. Therefore the goal was to minimize the number of the electronic components whose operation is influenced by variations in ambient temperature. The main topics discussed in the paper include the presentation of the measuring circuit’s configuration, the development of a low-cost embedded system, the calibration method and the solution implemented for eliminating the platforms limitation regarding the precision of the different mathematical calculations.

###### External Relations of German Cities Through Intra-firm Networks—A Global Perspective

firm j . The service value indicates the importance of a city to a firm’s office network based on an assessment of the size and function of a firm’s office(s) in a city. For each pair of cities in the matrix, the basic relation r ab,j is defined as an elemental interlock between city a and b in terms of firm j : (1) r a b , j = v a j ⋅ v b j $${{r}_{ab,j}}={{v}_{aj}}\cdot {{v}_{bj}}$$ The global network connectivity (GNC) of city a is then defined as: (2) G N C a = ∑ i , j

###### Developing the Reconfiguration Method to Increase Life Expectancy of Dynamic Wireless Sensor Network in Container Terminal

## Abstract

Nowadays control and management logistics solutions that are used in terminals apply sensor based technologies to identify and localize containers in the yard. Nevertheless, because of the limits in the existing sensor technical specification, the position of nodes is still affected by some errors or sometimes it cannot be determined in real-time systems due to battery fall.

The sensor nodes pertaining to information storage and processing are mainly equipped with an uninterrupted power supply, independent distribution network connectivity and low performance computing system. The capacity of data traffic near a coordinator node is much higher than in the distant points; as a result, the existing elements close to processing nodes faster than others stop operating due to a lack of electricity and, as a result, the network ceases its overall work.

The article describes the modification of network routing protocols for energy balancing in nodes, using the mobility of the coordinator node, which provides dynamic network reconfiguration possibilities.

###### Joint queue-perturbed and weakly coupled power control for wireless backbone networks

## Abstract

Wireless Backbone Networks (WBNs) equipped with Multi-Radio Multi-Channel (MRMC) configurations do experience power control problems such as the inter-channel and co-channel interference, high energy consumption at multiple queues and unscalable network connectivity. Such network problems can be conveniently modelled using the theory of queue perturbation in the multiple queue systems and also as a weak coupling in a multiple channel wireless network. Consequently, this paper proposes a queue perturbation and weakly coupled based power control approach forWBNs. The ultimate objectives are to increase energy efficiency and the overall network capacity. In order to achieve this objective, a Markov chain model is first presented to describe the behaviour of the steady state probability distribution of the queue energy and buffer states. The singular perturbation parameter is approximated from the coefficients of the Taylor series expansion of the probability distribution. The impact of such queue perturbations on the transmission probability, given some transmission power values, is also analysed. Secondly, the inter-channel interference is modelled as a weakly coupled wireless system. Thirdly, Nash differential games are applied to derive optimal power control signals for each user subject to power constraints at each node. Finally, analytical models and numerical examples show the efficacy of the proposed model in solving power control problems in WBNs.

###### Sensor network design for the estimation of spatially distributed processes

## Sensor network design for the estimation of spatially distributed processes

In a typical moving contaminating source identification problem, after some type of biological or chemical contamination has occurred, there is a developing cloud of dangerous or toxic material. In order to detect and localize the contamination source, a sensor network can be used. Up to now, however, approaches aiming at guaranteeing a dense region coverage or satisfactory network connectivity have dominated this line of research and abstracted away from the mathematical description of the physical processes underlying the observed phenomena. The present work aims at bridging this gap and meeting the needs created in the context of the source identification problem. We assume that the paths of the moving sources are unknown, but they are sufficiently smooth to be approximated by combinations of given basis functions. This parametrization makes it possible to reduce the source detection and estimation problem to that of parameter identification. In order to estimate the source and medium parameters, the maximum-likelihood estimator is used. Based on a scalar measure of performance defined on the Fisher information matrix related to the unknown parameters, which is commonly used in optimum experimental design theory, the problem is formulated as an optimal control one. From a practical point of view, it is desirable to have the computations dynamic data driven, i.e., the current measurements from the mobile sensors must serve as a basis for the update of parameter estimates and these, in turn, can be used to correct the sensor movements. In the proposed research, an attempt will also be made at applying a nonlinear model-predictive-control-like approach to attack this issue.

###### Multidimensional Risk Management for Underground Electricity Networks

## Abstract

In the paper we consider an electricity provider company that makes decision on allocating resources on electric network maintenance. The investments decrease malfunction rate of network nodes. An accidental event (explosion, fire, etc.) or a malfunctioning on underground system can have various consequences and in different perspectives, such as deaths and injuries of pedestrians, fires in nearby locations, disturbances in the flow of vehicular traffic, loss to the company image, operating and financial losses, etc. For this reason it is necessary to apply an approach of the risk management that considers the multidimensional view of the consequences. Furthermore an analysis of decision making should consider network dependencies between the nodes of the electricity distribution system. In the paper we propose the use of the simulation to assess the network effects (such as the increase of the probability of other accidental event and the occurrence of blackouts of the dependent nodes) in the multidimensional risk assessment in electricity grid. The analyzed effects include node overloading due to malfunction of adjacent nodes and blackouts that take place where there is temporarily no path in the grid between the power plant and a node. The simulation results show that network effects have crucial role for decisions in the network maintenance – outcomes of decisions to repair a particular node in the network can have significant influence on performance of other nodes. However, those dependencies are non-linear. The effects of network connectivity (number of connections between nodes) on its multidimensional performance assessment depend heavily on the overloading effect level. The simulation results do not depend on network type structure (random or small world) – however simulation outcomes for random networks have shown higher variance compared to small-world networks.

###### Modeling and Topological Properties of a V2I Sub Network in VANET Based on a Complex Network

Communications Workshops (INFOCOM WKSHPS), 2014, pp. 410-415. 8. Zhang, H., J. Li, Y. J. Lv. Structure Performance Analysis of Vehicular Ad Hoc Networks Based on Complex Network Theory. - Computer Modelling & New Technologies, Vol. 18, April 2014, No 2, pp. 46-51. 9. Mathew, N. M., P. C. Neelakantan. Analyzing the Network Connectivity Probability of a Linear VANETin Nakagami Fading Channels. - In: Lecture Notes in Computer Science. M. Chatterjee, K. Kothapalli, J. N. Cao and S. Rajsbaum, Eds. 2014, pp. 505-511. 10

###### Facilitation Fish Migration above the Discharge Sill Located on the Ialomiţa River Near Cave Ialomicioara

anadromous salmonids at cascades and falls. Trans. Am. Fish. Soc . 135, 668–679. Santucci Jr., V.J., Gephard, S.R., Pescitelli, S.M., (2005). Effects of multiple low-head dams on fish, macroinvertebrates, habitat, and water quality in the Fox River, Illinois. North American Journal of Fisheries Management 25, 975-992. Spens, J., Englund, G., Lundqvist, H., (2007). Network connectivity and dispersal barriers: using geographic information systems (GIS) tools to predict landscape scale distribution of a key predator (Esox lucius) among lakes. Journal of

###### Research on Intelligent Avoidance Method of Shipwreck Based on Bigdata Analysis

Environment. Science Technology and Engineering, 2016, 16(33):221-226. 8. Ho P F, Chen J C. WiSafe: Wi-Fi Pedestrian Collision Avoidance System. IEEE Transactions on Vehicular Technology, 2016, PP(99):1-1. 9. Chen Z, Fan M C, Zhang H T. How Much Control is Enough for Network Connectivity Preservation and Collision Avoidance?. IEEE Transactions on Cybernetics, 2015, 45(8):1647-1656. 10. 11.Gao, W. and W. Wang, The fifth geometric-arithmetic index of bridge graph and carbon nanocones. Journal of Difference Equations and