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Abstract

The explosive rise of wireless services necessitates a network connection with high bandwidth, high performance, low mistakes, and adequate channel capacity. Individual mobile users, as well as residential and business clusters are increasingly using the internet and multimedia services, resulting in massive increases in the internet traffic demand. Over the past decade, internet traffic has grown significantly faster than Moore’s law predicted. The current system is facing significant radio frequency spectrum congestion and is unable to successfully transmit growing amounts of (available) data to end users while keeping acceptable delay values in mind. Free space optics is a viable alternative to the current radio frequency technology. This technology has a few advantages, including fast data speeds, unrestricted bandwidth, and excellent security. Since free space optics is invisible to traffic type and data protocol, it may be quickly reliably and profitably integrated into an existing access network. Despite the undeniable benefits of free space optics technology under excellent channel conditions and its wide range of applications, its broad use is hampered by its low link dependability, especially over long distances, caused by atmospheric turbulence-induced decay and weather sensitivity. The best plausible solution is to establish a secondary channel link in the GHz frequency range that works in tandem with the primary free space optics link. A hybrid system that combines free space optics and millimeter wave technologies in this research is presented. The combined system offers a definitive backhaul maintenance, by drastically improving the link range and service availability.
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Bibliography

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Authors and Affiliations

Isanaka Lakshmi Priya
1
ORCID: ORCID
Murugappa Meenakshi
1
ORCID: ORCID

  1. Department of Electronics and Communication, Anna University, Guindy, Chennai 600025, India
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Abstract

Deriving the formulas for strain components, we are assuming, that cross-section of a rod being rotated in space during deformation does not need to be perpendicular to deformed centroid line. This not a quite intuitive assumption allows for more compact and easier formulas for strain tensor or equilibrium equations. Derived transformations between actual and initial coordinate system, components of strain tensor and virtual works principle for investigated spatially curved beams of bisymmetric cross-section are shown in this paper. Conformity with other models from referenced literature is also shown.

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Authors and Affiliations

R. Bijak
G. Kołodziej
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Abstract

Geography versus spatial management. The aim of the article is to draw attention to substantive connections that combine spatial management with geography, first of all with socio-economic geography. Both disciplines are of a multidimensional nature and they expose physical space as a field of their interests. The convergence of disciplines is also reflected in the research methodology – a spatial analysis has been developing in socio-economic geography since the 1960s by the so-called spatial direction. Both disciplines are competitive not only on the scientific, but also educational and utilitarian (socio-economic practice) market. The article focuses on the essence and a cognitive sense of both fields, in general, and on their scope of competence. Spatial management should be developed as part of basic sciences, including geography as its professional specialization.
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Authors and Affiliations

Andrzej Suliborski
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Abstract

In this paper the identification problem is considered for initial conditionsin a non-minimal state-space model that includes interpretable state variablesgenerated by non-stationary stochastic processes. In order to solve theidentification problem, structural restrictions are imposed on initial conditionsin a state-space model with redundant state variables. The correspondingrestricted maximum likelihood estimator of initial conditions is derived.The restricted estimator of initial conditions can be used in order tocompute uniquely identified realizations of interpretable latent variables. Theidentification problem is illustrated analytically using a simple structuraleconomic model.

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Authors and Affiliations

Victor Bystrov
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Abstract

The aim of this paper is to look at the quantitative dimension of public space resources in Polish cities, a comparative analysis of these resources, determining the share of public space in the urban spatial structure and referring this structure to European cities. The concept of ‘public space resources’ has been introduced, and is defined as those areas in the city that fulfill or can fulfill the functions of public space. This concept, and then the proposal of its operationalization, aimed to draw attention to the spatial and physical aspects of public space, which would allow to broaden and supplement social approaches in the study of public space. The quantitative approach to public space proposed in the paper also enabled a comparative research to assess the role of public space in the structure of Polish cities in a more objective manner and refer it to European cities.

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Authors and Affiliations

Krzysztof Stachowiak
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Abstract

The Space Research Centre of the Polish Academy of Sciences is the only Polish scientific research unit that is entirely devoted to using space technologies and satellite techniques to study the Earth, the area of space around it, and other celestial bodies in the Solar System.
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Authors and Affiliations

Ewelina Zambrzycka-Kościelnicka
1

  1. Space Research Centreof the Polish Academy of Sciences
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Abstract

The following article presents a selection of the most interesting examples of transformations of public space in towns and cities of varying sizes in Lesser Poland which were aided by European grants obtained from the pool of EU funds, with special attention to the Lesser Poland Regional Operational Programme (ROP) an also the Rural Development Programme (RDP) in the years 2007-2013. The presented findings are of a preliminary nature and are phase in the wider studies being conducted by the Author covering the multifaceted transformations of public space that have taken place and are taking place in Poland with the aid of European funding. The aim of these studies is an overall evaluation of how, in specific planning periods, the joining of the European Union and the possibility of taking advantage of Western experience, as well as financial support, influenced and influence today the transformations of public space in Polish towns and cities, and their influence on people’s thoughts and perceptions of such space.

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Authors and Affiliations

Dorota Wantuch-Matla
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Abstract

The process of designing control systems for devices operating in microgravity, on-orbit environment, requires testing to verify the effectiveness and characteristics of the algorithms. The key issue is to design a relevant environment in terrestrial conditions that affects both the linear and angular three-dimensional motion of a rigid body. This paper contains a description of the mechanical aspects of two test beds used to evaluate control algorithms planned for use in a space manipulator. Two solutions are presented: (i) a planar manipulator with a free base placed on an air-bearing table; and (ii) a test bed with a 7-DOF manipulator fixed through a force-torque measurement system to the base.

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Authors and Affiliations

Karol Seweryn
Kamil Grassmann
Konrad Rutkowski
Tomasz Rybus
Roman Wawrzaszek

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Abstract

This paper brings up elementary problems related to the creation of friendly public spaces in residential complexes as the main places of social integration. Contemporary social transformations are reflected in a new, intensified usage of public spaces which – offering more and more possibilities of satisfying human needs in the field of social contact, knowledge, recreation, stimulation etc. – provoke people and their activities to transfer “life” from a private space to a public space.

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Authors and Affiliations

Danuta Kupiec-Hyła
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Abstract

This paper discusses the challenges faced by the empirical macroeconomist and methods for surmounting them. These challenges arise due to the fact that macroeconometric models potentially include a large number of variables and allow for time variation in parameters. These considerations lead to models which have a large number of parameters to estimate relative to the number of observations. A wide range of approaches are surveyed which aim to overcome the resulting problems. We stress the related themes of prior shrinkage, model averaging and model selection. Subsequently, we consider a particular modelling approach in detail. This involves the use of dynamic model selection methods with large TVP-VARs. A forecasting exercise involving a large US macroeconomic data set illustrates the practicality and empirical success of our approach.

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Authors and Affiliations

Gary Koop
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Abstract

Convective and radiation heat transfer take place between various objects placed in open air space and their surroundings. These phenomena bring about heat losses from pipelines, building walls, roofs and other objects. One of the main tasks in energy auditing is the reduction of excessive heat losses. In the case of a low sky temperature, the radiation heat exchange is very intensive and the temperature of the top part of the horizontal pipelines or walls is lower than the temperature of their bottom parts. Quite often this temperature is also lower than the temperature of the surrounding atmospheric air. In the case of overhead heat pipelines placed in open air space, it is the ground and sky that constitute the surroundings. The aforementioned elements of surroundings usually have different values of temperature. Thus, these circumstances bring about difficulties during infrared inspections because only one ambient temperature which represents radiation of all surrounding elements must be known during the thermovision measurements. This work is aimed at the development of a method for determination of an equivalent ambient temperature representing the thermal radiation of the surrounding elements of the object under consideration placed in open air space, which could be applied at a fairly uniform temperature of the sky during the thermovision measurements as well as for the calculation of radiative heat losses.
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Authors and Affiliations

Tadeusz Kruczek
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Abstract

Recently, there has been research on high frequency dissipative mufflers. However, research on shape optimization of hybrid mufflers that reduce broadband noise within a constrained space is sparse. In this paper, a hybrid muffler composed of a dissipative muffler and a reactive muffler within a constrained space is assessed. Using the eigenvalues and eigenfunctions, a coupling wave equation for the perforated dissipative chamber is simplified into a four-pole matrix form. To efficiently find the optimal shape within a constrained space, a four-pole matrix system used to evaluate the acoustical performance of the sound transmission loss (STL) is evaluated using a genetic algorithm (GA).

A numerical case for eliminating a broadband venting noise is also introduced. To verify the reliability of a GA optimization, optimal noise abatements for two pure tones (500 Hz and 800 Hz) are exemplified. Before the GA operation can be carried out, the accuracy of the mathematical models has been checked using experimental data. Results indicate that the maximal STL is precisely located at the desired target tone. The optimal result of case studies for eliminating broadband noise also reveals that the overall sound power level (SWL) of the hybrid muffler can be reduced from 138.9 dB(A) to 84.5 dB(A), which is superior to other mufflers (a one-chamber dissipative and a one-chamber reactive muffler). Consequently, a successful approach used for the optimal design of the hybrid mufflers within a constrained space has been demonstrated.

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Authors and Affiliations

Min-Chie Chiu
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Abstract

A questionnaire survey was conducted in the residential quarters of Guangzhou, for which 582 elderly people over 60 years old were randomly recruited. The hearing impairment of the participants was evaluated using the Hearing Handicap Inventory for the Elderly (HHIE), The participants’ subjective responses to the acoustical environment of their living place and the impact of the living acoustical environment (LAE) on the participants were investigated. The results show that the participants with a low HHIE score and no hearing impairment evaluated their LAE more favourably, and they considered that the effect of the LAE on their daily life was weak. However, those with a high HHIE score and severe hearing impairment evaluated their LAE poorly, and considered its effect on their daily lives to be significant. For the elderly, the worse the hearing is, the higher their demand for a better LAE. Traffic, construction, residential quarters, and noise from next door or upstairs neighbours were the main noise sources in the elderly’s living places, and traffic noise, construction noise, and noise from next door and upstairs were the most influential sources. 28.9% of the respondents had trouble hearing what their family said in their living place. The elderly without hearing impairment considered that continuous noise was the main reason that they could not hear what their family said in their living place, while those with hearing impairment believed that their own hearing problem was a contributing factor.

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Authors and Affiliations

Zeng Youjie
Peng Jianxin
Zhao Lei
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Abstract

The matrix rectifier modulated by the classical space vector modulation (SVM) strategy generates common-mode voltage (CMV). The high magnitude and high du/dt of the CMV causes serious problems such as motor damage, electromagnetic noise and many others. In this paper, an improved SVM strategy is proposed by replacing the zero vectors with suitable couple of active ones that substantially eliminate the CMV. Theoretical analysis proves that the proposed strategy can reduce the amplitude of the CMV to half of the original value. In addition, the quality of the input and output waveforms is not affected by extra active vectors. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed strategy are shown.

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Authors and Affiliations

Xiao Liu
Qingfan Zhang
Dianli Hou
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Abstract

The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) inverter, the effect of neutral point voltage balancing which is caused by voltage vector is analyzed, and the relationship of the voltage offset and neutral point voltage is studied in this paper. This paper proposes a novel neutral point balance strategy for three-level NPC inverter based on space vector pulse width modulation (SVPWM). A voltage offset is added to the modulation wave, and a closed-loop neutral point voltage balance control system is designed. In the control system, the dwelling time of synthesis voltage vectors for SVPWM is varied to solve the problem of the unbalance of the neutral point voltage, the sequence of the voltage vectors maintains unchanging. Simulation and experimental results show the neutral point voltage balancing control strategy based on SVPWM is effective.

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Authors and Affiliations

Bo Gong
Shanmei Cheng
Yi Qin
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Abstract

In the field of power and drive systems, electrical AC machines are mostly modeled using a set of explicit ordinary differential equations in a state space representation. It is shown, that by using other equation types for simulation, algebraic constraints arising from aggregating several machines to a more complex system can directly be considered. The effects of different model variants on numerical ODE/DAE solvers are investigated in the focus of this work in order perform efficient simulations of larger systems possessing electrical AC machines.

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Authors and Affiliations

Michael Popp
Patrick Laza
Wolfgang Mathis
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Abstract

The results of shielding effectiveness (SE) measurements of textile materials containing metal by the free-space transmission technique (FSTT) in the 1-26.5 GHz frequency range are presented in the paper. It is shown that experimental data processing using time-domain gating (TDG) makes it possible to effectively remove diffracted and reflected components from the desired signal. The comparison with the results obtained by other techniques, namely modified FSTT with TDG and coaxial line probe technique (ASTM D4935-99) is given. The comparison shows that the proposed technique gives more reasonable results while the measurement set-up is simpler in realization.

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Nadezhda Dvurechenskaya
Paweł R. Bajurko
Ryszard J. Zieliński
Yevhen Yashchyshyn
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Abstract

The article concerns problems with shaping contemporary housing estates. By analyzing housing structures designed in recent years, the aim was to demonstrate the importance of creating the continuity of public spaces in order to achieve places seen as attractive and presenting features of high quality urban space. Essential for the research is the question about the conditions which should be fulfi lled when creating the ideal residential place which then leads to a series of answers. These included indicating a good location with functional and aesthetic urban/architectural solutions. Environmental issues are important as well. Regardless of whether it is a multi-family dwelling or a single family house, a good neighborhood and its location in a well-connected place with necessary basic services within walking range are important. It is also signifi cant how the public space was shaped and whether a natural network was created. Due to factors such as the specifi city of the structure’s location in the city and diff erent surfaces of designed estates, as well as the variety of residential buildings being constructed, it is often diffi cult to assess them unambiguously. Importantly, this assessment also includes social and economic aspects as well as technical issues. However, by using multi-directional research it can be noted that the forms of public spaces within housing complexes play an important role in the creation of high-quality structures, perceived as attractive not only by the residents.

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Authors and Affiliations

Izabela M. Burda
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Abstract

The main objective of the article is an attempt to indicate factors which determine the image of a city as a good place to live as well as to reveal the ways in which they affect the citizens’ quality of life. In order to do so, the author selected the city of Gdynia which is perceived as the best city to live in by its citizens. Among the most important factors determining the quality of life in general there are: the scale of a city, local identity, public spaces, symbolic places, housing environment, perception of a place, personal satisfaction of a place where a particular person lives, urban policies as well as presence and activeness of local leaders. The article presents the results of a social study carried out by the author herself during two periods of time – in 2004 and 2014 as well as the results of the Social Diagnosis 2015.

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Magdalena Szmytkowska
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Abstract

The article is an attempt to collate and present the existing works of Polish geographers who focused on public space in cities, taking two main theoretical and methodological approaches – objective and subjective – under consideration. The article discusses different definitions of the analysed term in an interdisciplinary context as well as indicates main aspects and research directions in geographical studies along with the scholars representing them. Moreover, the authors make an attempt to evaluate the existing state of the art and try to set future perspectives for geographical studies on public space in cities. The article finishes with the authors’ conclusions regarding the necessity to continue the research on public space and the role Polish geographers shall play in it.

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Authors and Affiliations

Anita Kulawiak
Magdalena Szmytkowska
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Abstract

The article is an attempt to analyze the spatio-pedagogical discourse of the German social pedagogy. It represents only a fragment of reflection on the turns in paradigm of place/ space (spatial turn), as pedagogical terms. & e authors seek to answer the question what is the space and place, and what concepts in the field of reflection on the place/space run in the German social pedagogy. The text introduces, inter alia, the relational concept of space developed by Martina Löw, duality of space and the concept of spacing. Active creation of urban space, the spatial dimension of the relationship and its dynamics are subjected to discussion. The article presents critical approach to the notion of transdisciplinary space, and space-oriented social work. Finally, it provides the incentive for in-depth, international analyzes of spatio-pedagogical theories.

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Authors and Affiliations

Jacqueline Puchert
Aleksandra Kurowska-Susdorf
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Abstract

In this paper a small time local controllability, naturally defined in a configuration space, is transferred into a task-space. It was given its analytical characterization and practical implications. A special attention was put on singular configurations. Theoretical considerations were illustrated with two calculation examples. An extensive comparison of the proposed construction with the controllability defined in an endogenous configuration space approach was presented pointing out to their advantages and disadvantages.

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Authors and Affiliations

Ignacy Duleba
ORCID: ORCID
Arkadiusz Mielczarek
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Abstract

The subject of this paper is the study of the specificity of the transformation of the urban public spaces of the Western world and the problem of the multi form nature of this phenomenon. The Author uses such concepts as that of the "hybrid" and of "hybridization" borrowed from the field of natural sciences and explains the reasons for their introduction within this specific scope of research in a broad manner.

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Authors and Affiliations

Dorota Wantuch-Matla

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