bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Metaheuristic Based Approach for Threshold Optimization for Spectrum Sensing in Cognitive Radio Networks
Authors: Mahendru Garima , Shukla Anil K. , Patnaik Lalit M. 
Published: October 2019

Background:
The mounting growth of wireless technology is attracting a high demand
for the frequency spectrum. The measurements of spectrum usage depict that a significant portion
of the spectrum lays unoccupied or overcrowded. The main cause of the glitch is the existing inefficient
and fixed scheme of spectral allocation. Cognitive radio is one such technology that permits
wireless devices to detect the unused frequency band and reconfigure its operating parameters to attain
the required quality of service.

Objective:
To permit the dynamic allocation of the frequency band, spectrum sensing is performed
which is an essential function of Cognitive radio and involves detection of an unused spectrum space
to set up a communication link.

Method:
This paper presents a meta-heuristic approach for selection of a decision threshold for energy
detection based spectrum sensing. At low SNR and in the presence of noise uncertainty, the
performance of energy detection method fails. A novel adaptive double threshold based spectrumsensing
method is proposed to avoid such a sensing failure. Further, the metaheuristic approach employs
Particle Swarm Optimization (PSO) algorithm to compute an optimal value of the threshold to
attain robustness against noise uncertainty at low SNR.

Results:
The simulation results of the proposed metaheuristic double threshold based spectrum sensing
method demonstrate enhanced performance in comparison to the existing methods in terms of
reduced error rate and increased detection probability. Some of the existing methods have been analyzed
and compared from a survey of recent patents on spectrum sensing methods to support the new
findings The concept of adaptive thresholding improves the detection probability by 39 % and 27
% at noise uncertainty of 1.02 and 1.04, respectively at a signal to noise ratio of -10 dB. Furthermore,
the error probability reduces to 58% at the optimal threshold using Particle Swarm Optimization
(PSO) algorithm for the signal to noise ratio of -9 dB.

Conclusions:
The main outcome of this work is the reduction in the probability of sensing failure
and improvement in the detection probability using adaptive double thresholds at low SNR. Further,
particle swarm optimization helps in obtaining the minimum probability of error under noise uncertainty
with an optimal threshold.
Vasorelaxant Effect of Novel Nitric Oxide-Hydrogen Sulfide Donor Chalcone in Isolated Rat Aorta: Involvement of cGMP Mediated sGC and Potassium Channel Activation
Authors: Sherikar Amol , Dhavale Rakesh , Bhatia Manish 
Published: October 2019

Background and Objective: :
Recently, nitric oxide (NO) and hydrogen sulfide (H2S)
donating moieties were extensively studied for their role in the vasculature as they are responsible for
many cellular and pathophysiological functioning. The objective of the present study is to evaluate
novel NO and H2S donating chalcone moieties on isolated rat aorta for vasorelaxation, and to
investigate the probable mechanism of action.

Methods::
To extend our knowledge of vasorelaxation by NO and H2S donor drugs, here we
investigated the vasorelaxing activity of novel NO and H2S donating chalcone moieties on isolated rat
aorta. The mechanism of vasorelaxation by these molecules was investigated by performing in vitro
cGMP mediated sGC activation assay and using Tetraethylammonium chloride (TEA) as a potassium
channel blocker and Methylene blue as NO blocker.

Results::
Both NO and H2S donating chalcone moieties were found to be potent vasorelaxant. The
compound G4 and G5 produce the highest vasorelaxation with 3.716 and 3.789 M of pEC50,
respectively. After the addition of TEA, G4 and G5 showed 2.772 and 2.796 M of pEC50, respectively.
The compounds Ca1, Ca2, and D7 produced significant activation and release of cGMP mediated sGC
which was 1.677, 1.769 and 1.768 M of pEC50, respectively.

Conclusion: :
The vasorelaxation by NO-donating chalcones was blocked by Methylene blue but it did
not show any effect on H2S donating chalcones. The vasorelaxing potency of NO-donating molecules
was observed to be less affected by the addition of TEA but H2S donors showed a decrease in both
efficacy and potency. The cGMP release was more in the case of NO-donating molecules. The tested
compounds were found potent for relaxing vasculature of rat aorta.
Ecotoxicity Study of Iron Oxide Nanoparticles on Chlorella Sp. and Daphnia Magna
Authors: ERTİT TAŞTAN Burcu , KARS DURUKAN İlknur , ATEŞ Mehmet 
Published: October 2019

Nanoparticles have great impact due to their tremendous industrial
applications. However, their applications have produced toxicity effects on the
aquatic environments and their detailed analyses are not clearly understood.
Iron oxide nanoparticles (Fe2O3 NPs) are being used
extensively in many industries but are considered highly toxic to aquatic
species residing in surface waters. This paper demonstrates the acute
toxicity of a-Fe2O3 and g-Fe2O3NPs in two aquatic
species. The effects of various concentration (0, 50, 100, 250, 500 and 1000
mg/L) of a-Fe2O3 and g-Fe2O3 on the sensitivity
response of the Chlorella sp. and D. magna were investigated. The growth
of microalgal decreased with increased concentration of the a-Fe2O3 and g-Fe2O3 NPs concentrations but
did not show a significant toxic effect. The EC50 concentration
value was 500 mg/L and LD50 concentration value was 1000 mg/L for a-Fe2O3 treated daphnids in 72 h,
respectively. The findings demonstrate the significant evidence in
understanding acute toxicity of Fe2O3 NPs for environmental
protection as part of risk assessment strategies.
DIVERSITY OF ARTHROPOD PREDATOR IN SWAMP RICE FIELDS IN SOUTH SUMATERA
Authors: Meidalima Dewi , Kawaty Ruarita Ramadhalina , B. Gunawan Erlan 
Published: October 2019

The abundance and diversity of arthropod in agro ecosystem depend on the level of synthetic pesticide contamination. This study aimed to explore, identify and analyze the diversity and abundance of predatory arthropods in swamp rice fields treated with pesticide application (in Pemulutan) and without pesticide application (in Musi 2). The swamp rice fields in Pemulutan are bordered by village, river and forest. The methods were survey and direct observation on 3 ha and 2 ha of swamp rice fields in Pemulutan and Musi 2, Palembang. Sampling of predatory arthropods were conducted at 20, 50, 80 and 110 days after rice planting using pitfall trap. Identification of predatory arthropods was conducted at Laboratory of Entomology showing that the arthropod collected consisted of 17 species of insects and 9 species of Arachnida. In Pemulutan Ogan Ilir were found 19 species (10 species of insect and 9 species of Arachnida) at the village area. In the area that was bordered by river were found 8 species (7 insect and 1 Arachnida). In the area bordered by forest were found 22 species (10 species of insects and 12 species of Arachnida). The diversity level, number of species, and arthropod specimen in the field without pesticide application at Musi 2 were higher than those in the fields with pesticide application in Pemulutan.
The relations between the quality of financial statements and corporate governance
Authors: Franczak Iwona 
Published: October 2019

Abstract
Business entities operated in the form of capital companies, to maintain reliability and transparency of the activities conducted, should observe general supervisory framework of legal nature. The primary objective of the information policy is to provide stock market participants with appropriate standards of company transparency which through the corporate governance regulations should lead to the improvement in the quality of financial reporting. Financial statements should be reliable as it is only then that their aims and targets are met, and the image of business they depict should be created according to the true and fair principle, invoking the responsibility of individuals supervising the process of drawing up a financial statement. The aim of the paper is to indicate the essence of the relationship between the quality of financial statements and the application of corporate governance principles. The paper uses the analysis of regulations and review of literature in the field of corporate governance and reporting of listed companies. The results of the analysis confirm that the quality of reported information determines the effectiveness of corporate supervision; that integrated reporting (IR) is a tool enabling organizations to communicate their value to investors; and that corporate supervision allows said organizations to adopt the comprehensive approach in developing sustainable value.
Gravelling Test for Rail Windshield
Authors: Bilar Adam , Boguszewicz Paweł , Perkowski Witold 
Published: October 2019

Abstract
During preliminary tests of locomotive windshield resistance to gravelling, according to the applicable standard PN-EN 15152:2007, carried out in the Institute of Aviation, the problem of the projectile overturning after leaving the cannon barrel was detected. Three tests recorded with a high-speed camera are presented in this article. This problem was found to be due to the incorrect projectile geometry.
In order to stabilise the trajectory of the projectile, four types of projectiles were made using military experience. All of them meet relevant test conditions from the point of view of the test piece (locomotive windshield). The best projectile modification was obtained in the tests with an average deviation of the expected impact angle of 11° compared to 75° for a projectile made exactly according to the guidelines of the standard. Each of 22 modified projectiles hit the test piece with the tip, while out of the 12 original projectiles only 4 hit the test piece with the tip. The impact test results confirm that it is possible to perform a gravelling test according to the standard concept, but it seems necessary to clarify the standard requirements and to modify the projectile shape.
The article contains a proposal for the projectile modification and highlights inaccuracies in the standard concerning the gravelling test.
Estimation of the Vessel's Sailing Resistance in the Preliminary Analyses
Authors: Charchalis Adam 
Published: October 2019

Abstract
In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.
Wavelet Transform in Vibroacoustic Diagnostic of Machines
Authors: Haller Piotr , Jankowski Antoni , Kaźmierczak Andrzej , Wróbel Radosław 
Published: October 2019

Abstract
This article discusses the use of wavelet decomposition in the diagnostics of vibrometric signals of an engine. Apart from presenting the possibility of using wavelets in diagnostics, the authors take up the subject of the applicability range of processing for stationary signals, which until now has been reserved for non-stationary signals. A unified definition of signal stationarity has been proposed, which is not based on statistics. The authors presented methods of wavelet decomposition of a vibrometric signal of combustion engine vibrations, measured with the use of LDV (Laser Doppler Vibrometry). Laser measurements allows for studying an object without ‘touching’ its housing. Basing on the relative velocity of engine vibrations, the authors indicate how reliable vibrations are in diagnostics. Despite higher costs, this measurement method gives better results (for specific cases) than acoustic studies. Transform – wavelet decomposition is a solution hardly ever used in machine diagnostics; it is more often applied in medicine and image recognition. The authors presented the differences that can be obtained for different levels of decomposition, and also presented the impact on the engine condition assessment through the use of filtering (windowing) the signal before decomposition.
Influence of Marine Main Engine Foundations on the Results of Vibration Calculations
Authors: Murawski Lech 
Published: October 2019

Abstract
The article presents an influence of foundations of slow-speed main engine body on the results of numerical analysis of the engine dynamic stiffnesses and thermal deformations. The engine body is much stiffer than its foundation pads and ship hull (double bottom) – boundary conditions of the engine. Especially for the high power, marine engines, the correct model of the boundary conditions plays a key role during the analyses. Therefore, modelling method of engine foundation (boundary conditions) of that kind of model is essential during the analyses. During shaft line alignment and crankshaft springing analyses, knowledge of dynamic stiffnesses characteristics and thermal displacements of radial (main) bearings is significant. Those data of marine main engine body are difficult to estimate because of lack of available documentation and complicated shape of the engine and ship hull. The article presents the methodology of the characteristics determination of the marine engine's body as well as the example of computations for a MAN B&W K98MC type engine (power: 40000 kW, revolutions: 94 rpm) mounted on a 3000 TEU (twenty-foot container equivalent unit) container ship (length: 250 m). Numerical analyses were performed with usage of Nastran software based on Finite Element Method. The FEM model of the engine body comprised over 800 thousand degree of freedom.
Subjective Risk Estimation of the Rare Event
Authors: Nguyen Hoang 
Published: October 2019

Abstract
In the safety engineering, the most frequently disadvantage in risk estimation is the lack of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, they may have uncertainty in the perceiving and evaluation of the problem considered or limited knowledge of the rare events, such as the consequences of the seagoing ship propulsion failures. The probabilistic models of the risk estimation turn out to be insufficient in modelling the subjective uncertainty. The fuzzy methods are viewed to be powerful in dealing with ambiguity and uncertainty that can be used to handle with the subjective estimation. This article addresses the intuitionistic fuzzy method in the subjective estimation of the ship propulsion failure consequences as rare event risk. In the article, a subjective model of the ship propulsion risk is developed as scenarios of the different subsequent consequences of loss of ship propulsion function until a seriously severe accident resulting in loss of seaworthiness. The model proposes an approach combining AHP method and intuitionistic fuzzy method to assess the occurrence probability and severe probability of these rare events based on the expert opinions. In order to show the applicability of the proposed model, a study case of the propulsion risk of the container carrier operating on the North Atlantic lines is conducted.
Determination of Coefficients of Energy Losses Occurring in a Constant Capacity Pump Working in a Typical Hydrostatic Drive
Authors: Skorek Grzegorz 
Published: October 2019

Abstract
In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.
Health Monitoring in Landing Gears
Authors: Skorupka Zbigniew , Tywoniuk Andrzej 
Published: October 2019

Abstract
Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis.
In this article, authors describe possible landing gears health monitoring methods based on authors ’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.
Modelling of Vane and Rotor Blade Rows in Simulations of Gas Turbine Performance
Authors: Sznajder Janusz 
Published: October 2019

Abstract
A method of modelling of nozzle and rotor blade rows of gas turbine dedicated to simulations of gas turbine performance is proposed. The method is applicable especially in early design stage when many of geometric parameters are yet subject to change. The method is based on analytical formulas derived from considerations of flow theory and from cascade experiments. It involves determination of parameters of gas flow on the mean radius of blade rows. The blade row gas exit angle, determined in turbine design point is a basis for determination of details of blade contour behind the throat position. Throat area is then fixed based on required maximum mass flow in critical conditions. Blade leading edge radius is determined based on flow inlet angle to the blade row in the design point. The accuracy of analytical formulas applied for definition of blade contour details for assumed gas exit angle was verified by comparing the results of analytical formulas with CFD simulations for an airfoil cascade. Losses of enthalpy due to non-isentropic gas flow are evaluated using the analytical model of Craig and Cox, based on cascade experiments. Effects of blade cooling flows on losses of total pressure of the gas are determined based on analytical formulas applicable to film cooling with cooling streams blowing from discrete point along blade surface, including leading and trailing edges. The losses of total pressure due to film cooling of blades are incorporated into the Craig and Cox model as additional factor modifying gas flow velocities.
An Overview of Different Possibilities to Master the Challenge of Coupling an AE-Sensor to an Object of Interest Partly Using Examples of Previous Investigations
Authors: Ziegler Burkhard , Dudzik Krzysztof 
Published: October 2019

Abstract
Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AE-waves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn–online–information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.