bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital Signal Processing Approach in Air Coupled Ultrasound Time Domain Beamforming
Authors: Herman Krzysztof , Gudra Tadeusz , Furmankiewicz Joanna
Published: April 2015

The work presents the results of experimental study on the possibilities of determining the source of an ultrasonic signal in two-dimensional space (distance, horizontal angle). During the research the team used a self-constructed linear array of MEMS microphones. Knowledge in the field of sonar systems was utilized to analyse and design a location system based on a microphone array. Using the above mentioned transducers and broadband ultrasound sources allows a quantitative comparison of estimation of the location of an ultrasonic wave source with the use of broadband modulated signals (modelled on bats' echolocation signals) to be performed. During the laboratory research the team used various signal processing algorithms, which made it possible to select an optimal processing strategy, where the sending signal is known.
Detection of Montage in Lossy Compressed Digital Audio Recordings
Authors: Korycki Rafał
Published: April 2015

This paper addresses the problem of tampering detection and discusses methods used for authenticity analysis of digital audio recordings. Presented approach is based on frame offset measurement in audio files compressed and decoded by using perceptual audio coding algorithms which employ modified discrete cosine transform. The minimum values of total number of active MDCT coefficients occur for frame shifts equal to multiplications of applied window length. Any modification of audio file, including cutting off or pasting a part of audio recording causes a disturbance within this regularity. In this study the algorithm based on checking frame offset previously described in the literature is expanded by using each of four types of analysis windows commonly applied in the majority of MDCT based encoders. To enhance the robustness of the method additional histogram analysis is performed by detecting the presence of small value spectral components. Moreover, computation of maximum values of nonzero spectral coefficients is employed, which creates a gating function for the results obtained based on previous algorithm. This solution radically minimizes a number of false detections of forgeries. The influence of compression algorithms' parameters on detection of forgeries is presented by applying AAC and Ogg Vorbis encoders as examples. The effectiveness of tampering detection algorithms proposed in this paper is tested on a predefined music database and compared graphically using ROC-like curves.
An Introduction to Virtual Phased Arrays for Beamforming Applications
Authors: Comesana Daniel Fernández , Holland Keith R. , Escribano Dolores García , de Bree Hans-Elias
Published: April 2015

Sound localization problems are usually tackled by the acquisition of data from phased microphone arrays and the application of acoustic holography or beamforming algorithms. However, the number of sensors required to achieve reliable results is often prohibitive, particularly if the frequency range of interest is wide. It is shown that the number of sensors required can be reduced dramatically providing the sound field is time stationary. The use of scanning techniques such as “Scan & Paint” allows for the gathering of data across a sound field in a fast and efficient way, using a single sensor and webcam only. It is also possible to characterize the relative phase field by including an additional static microphone during the acquisition process. This paper presents the theoretical and experimental basis of the proposed method to localise sound sources using only one fixed microphone and one moving acoustic sensor. The accuracy and resolution of the method have been proven to be comparable to large microphone arrays, thus constituting the so called “virtual phased arrays”.
Experimental Study of Silent Sonar
Authors: Marszal Jacek
Published: April 2015

Stealth is a frequent requirement in military applications and involves the use of devices whose signals are difficult to intercept or identify by the enemy. The silent sonar concept was studied and developed at the Department of Marine Electronic Systems of the Gdansk University of Technology. The work included a detailed theoretical analysis, computer simulations and some experimental research. The results of the theoretical analysis and computer simulation suggested that target detection and positioning accuracy deteriorate as the speed of the target increases, a consequence of the Doppler effect. As a result, more research and measurements had to be conducted to verify the initial findings. To ensure that the results can be compared with those from the experimental silent sonar model, the target's actual position and speed had to be precisely controlled. The article presents the measurement results of a silent sonar model looking at its detection, range resolution and problems of incorrect positioning of moving targets as a consequence of the Doppler effect. The results were compared with those from the theoretical studies and computer simulations.
Transistor Effect in the Cochlear Amplifier
Authors: Kiełczyński Piotr , Szalewski Marek
Published: April 2015

The paper presents a new electromechanical amplifying device i.e., an electromechanical biological transistor. This device is located in the outer hair cell (OHC), and constitutes a part of the Cochlear amplifier. The physical principle of operation of this new amplifying device is based on the phenomenon of forward mechanoelectrical transduction that occurs in the OHC's stereocilia. Operation of this device is similar to that of classical electronic Field Effect Transistor (FET). In the considered electromechanical transistor the input signal is a mechanical (acoustic) signal. Whereas the output signal is an electric signal. It has been shown that the proposed electromechanical transistor can play a role of the active electromechanical controlled element that has the ability to amplify the power of input AC signals. The power required to amplify the input signals is extracted from a battery of DC voltage. In the considered electromechanical transistor, that operates in the amplifier circuit, mechanical input signal controls the flow of electric energy in the output circuit, from a battery of DC voltage to the load resistance. Small signal equivalent electrical circuit of the electromechanical transistor is developed. Numerical values of the electrical parameters of the equivalent circuit were evaluated. The range, which covers the levels of input signals (force and velocity) and output signals (voltage, current) was determined. The obtained data are consistent with physiological data. Exemplary numerical values of currents, voltages, forces, vibrational velocities and power gain (for the assumed input power levels below 1 picowatt (10-12 W)), were given. This new electromechanical active device (transistor) can be responsible for power amplification in the cochlear amplifier in the inner ear.
Changes in Distortion Product Otoacoustic Emission Caused by Contralateral Broadband Noise
Authors: Ozimek Edward , Wicher Andrzej
Published: April 2015

The main purpose of this investigation was to measure the effect of contralateral acoustic stimulation (CAS) on distortion product otoacoustic emission (DPOAE) in twenty human ears, for a ratio of primary tones f2/f1 = 1.22 and a wide frequency range of f2 (1.4-9 kHz), for two intensity levels of primary tones (L1 = 60 dB SPL; L2 = 50 dB SPL and L1 = 70 dB SPL; L2 = 60 dB SPL) and two intensity levels of CAS (50 and 60 dB SPL). It was found that in the presence of CAS, in the majority of cases the DPOAE level decreased (suppression), but it might also increase (enhancement) or remain unchanged depending on the frequency. The mean suppression level of the component of the frequency fDP = 2f1 f2 might be approximated by a linearly decreasing function of the f2 frequency of primary tones. The slope of this function was negative and increased with an increase of the contralateral stimulation level. The higher was the contralateral noise level the greater was the suppression. For the fDP level below about 15 dB SPL, suppression was observed in a substantial number of measurement cases (in about 85% of all measured cases on average). When the fDP level was higher than 15 dB SPL, only suppression (not enhancement) was observed.
Noninvasive Imaging of Thermal Fields Induced in Soft Tissues In Vitro by Pulsed Focused Ultrasound Using Analysis of Echoes Displacement
Authors: Karwat Piotr , Litniewski Jerzy , Kujawska Tamara , Secomski Wojciech , Krawczyk Kazimierz
Published: April 2015

Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the most suitable for the temperature control. This paper presents an implementation of the ultrasonic echoes displacement estimation technique for monitoring of local temperature rise in tissue during its heating by focused ultrasound The results of the estimation were compared to the temperature measured with thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique
Acoustical Boundary Elements: Theory and Virtual Experiments
Authors: Piscoya Rafael , Ochmann Martin
Published: April 2015

This paper presents an overview of basic concepts, features and difficulties of the boundary element method (BEM) and examples of its application to exterior and interior problems. The basic concepts of the BEM are explained firstly, and different methods for treating the non-uniqueness problem are described. The application of the BEM to half-space problems is feasible by considering a Green's Function that satisfies the boundary condition on the infinite plane. As a special interior problem, the sound field in an ultrasonic homogenizer is computed. A combination of the BEM and the finite element method (FEM) for treating the problem of acoustic-structure interaction is also described. Finally, variants of the BEM are presented, which can be applied to problems arising in flow acoustics.
System for Automatic Transcription of Sessions of the Polish Senate
Authors: Marasek Krzysztof , Koržinek Danijel , Brocki Łukasz
Published: April 2015

This paper describes research behind a Large-Vocabulary Continuous Speech Recognition (LVCSR) system for the transcription of Senate speeches for the Polish language. The system utilizes severalcomponents: a phonetic transcription system, language and acoustic model training systems, a Voice Activity Detector (VAD), a LVCSR decoder, and a subtitle generator and presentation system. Some of the modules relied on already available tools and some had to be made from the beginning but the authors ensured that they used the most advanced techniques they had available at the time. Finally, several experiments were performed to compare the performance of both more modern and more conventional technologies.
Spatial and Frequency Compounding in Application to Attenuation Estimation in Tissue
Authors: Klimonda Ziemowit , Litniewski Jerzy , Karwat Piotr , Nowicki Andrzej
Published: April 2015

The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.
A Multi-Level Robust and Perceptually Transparent Blind Audio Watermarking Scheme Using Wavelets
Authors: Husain Farooq , Farooq Omar , Khan Ekram
Published: April 2015

In this paper, a robust and perceptually transparent single-level and multi-level blind audio watermarking scheme using wavelets is proposed. A randomly generated binary sequence is used as a watermark, and wavelet function coding is used to embed the watermark sequence in audio signals. Multi-level watermarking is used to enhance payload capacity and can be used for a different level of security. The robustness of the scheme is evaluated by applying different attacks such as filtering, sampling rate alteration, compression, noise addition, amplitude scaling, and cropping. The simulation results obtained show that the proposed watermarking scheme is resilient to various attacks except cropping. Perceptual transparency of watermark is measured by using Perceptual Evaluation of Audio Quality (PEAQ) basic model of ITU-R (PEAQ ITU-R BS.1387) on Speech Quality Assessing Material (SQAM) given by European Broadcasting Union (EBU). Average Objective Difference Grade (ODG) measured for this method is -0.067 and -0.080 for single-level and multi-level watermarked audio signals, respectively. In the proposed single-level digital audio watermarking scheme, the payload capacity is increased by 19.05% as compared to the single-level Chirp-Based Digital Audio Watermarking (CB-DAWM) scheme.
The Characteristic of Sound Reflections from Curved Reflective Panels
Authors: Szelag Agata , Kamisiński Tadeusz , Lewińska Mirosława , Rubacha Jarosław , Pilch Adam
Published: April 2015

The paper presents the verification of a solution to the narrow sound frequency range problem of flat reflective panels. The analytical, numerical and experimental studies concerned flat panels, panels with curved edges and also semicircular elements. There were compared the characteristics of sound reflected from the studied elements in order to verify which panel will provide effective sound reflection and also scattering in the required band of higher frequencies, i.e. above the upper limit frequency. Based on the conducted analyzes, it was found that among some presented solutions to narrow sound frequency range problem, the array composed of panels with curved edges is the most preferred one. Nevertheless, its reflection characteristic does not meet all of the requirements, therefore, it is necessary to search for another solution of canopy which is effective over a wide frequency range.
Driver Filter Design for Software-Implemented Loudspeaker Crossovers
Authors: Shu-Nung Yao
Published: April 2015

A hybrid method is presented for the integration of low-, mid-, and high-frequency driver filters in loud-speaker crossovers. The Pascal matrix is exploited to calculate denominators; the locations of minimum values in frequency magnitude responses are associated with the forms of numerators; the maximum values are used to compute gain factors. The forms of the resulting filters are based on the physical meanings of low-pass, band-pass, and high-pass filters, an intuitive idea which is easy to be understood. Moreover, each coefficient is believed to be simply calculated, an advantage which keeps the software-implemented crossover running smoothly even if crossover frequencies are being changed in real time. This characteristic allows users to efficiently adjust the bandwidths of the driver filters by subjective listening tests if objective measurements of loudspeaker parameters are unavailable. Instead of designing separate structures for a low-, mid-, and high-frequency driver filter, by using the proposed techniques we can implement one structure which merges three types of digital filters. Not only does the integration architecture operate with low computational cost, but its size is also compact. Design examples are included to illustrate the effectiveness of the presented methodology
Comparison of Formulas Obtained for Analytical and LQ Idea Approaches to Determine the Optimal Actuator Location in Active Multimodal Beam Vibration Reduction
Authors: Żołopa Elżbieta , Brański Adam
Published: April 2015

In this paper an active multimodal beam vibration reduction via one actuator is considered. The optimal actuator distribution is analyzed with two methods: an exact mathematical principles and the LQ problem idea. It turned out that the same mathematical expressions are derived. Thus, these methods are equivalent.
In Memoriam. Professor Stefan ERNST
Authors: Chorazewski Mirosław
Published: April 2015

It is with great sadness that we inform our readers about the recent death of Professor Stefan Ernst. Stefan Ernst was born in Piaśniki, Upper Silesia, on November 03, 1934, to parents of Polish-German descent. His primary education started during the war at a German-speaking school in Wirek and continued in Olesno, where he also got his secondary education. As chemistry studies were not yet available at the University ofWrocław in 1953, he started studying biology and switched to chemistry a year later. He received his master’s degree in chemistry in 1959, as one of the first graduates in that major. Then, he started his work on application of thermodynamics and molecular acoustics in investigation of liquid phases under the guidance of the Prof. Bogusława Jeżowska-Trzebiatowska. On 28 November 1967, he defended his PhD thesis entitled “Association-Dissociation Equilibria and the Structure of Uranyl Compounds in Organic Solvents” at the University of Wrocław. Professor Stefan Ernst was a linguist, a polyglot, a renowned thermodynamisist and a researcher of molecular acoustics. With great regret and shock we have learned of his sudden and unexpected death on August 03, 2014, in a hospital in Kraków.
Acid Mediated Ring Closing Metathesis: A Powerful Synthetic Tool Enabling the Synthesis of Clinical Stage Kinase Inhibitors
Authors: William Anthony D. , Lee Angeline C.-H.
Published: April 2015

The powerful olefin metathesis reaction was employed for the construction of late-phase clinical agents SB1317 and SB1518. In both cases RCM seems to proceed only in the presence of an acid and to predominantly furnish trans isomers. In case of SB1518 it proceeded in the presence of acid HCl, while for SB1317, it mainly proceeds in the presence of TFA (trifluroacetic acid).
D'un mythe à l'autre : de l'ignorance des lois à la présomption du choix éclairé chez les conjoints en union libre
Authors: Belleau Hélène
Published: April 2015

Plusieurs pays ont réagi à l'augmentation des unions libres sur le plan juridique en présumant que les conjoints non mariés sont bien informés des droits et responsabilités qui les concernent et qu'ils prennent une décision éclairée. Cet article ébranle cette présomption en traitant de trois prépositions sous-jacentes. L'analyse de la littérature internationale montre (1) que les questions juridiques entrent rarement dans la décision des couples de se marier ou non; (2) que l'étendue des méconnaissances des lois et la nature des « erreurs » commises témoignent du fait que l'intuition juridique des citoyens s'appuie sur ce qu'ils croient refléter la réalité qui les entoure et ce qu'ils croient être juste ; et (3) que les conjoints évitent souvent d'anticiper la rupture, car le faire peut avoir un coût négatif très réel sur la relation conjugale elle-même. Une meilleure connaissance des lois ne conduirait donc pas nécessairement les conjoints à se prémunir des conséquences négatives d'une rupture. L'amélioration de la littératie juridique des principaux concernés, bien que nécessaire, semble donc peu prometteuse. Cette conclusion conduit l'auteure à proposer une autre avenue, soit celle d'imposer aux couples un cadre minimal avec la possibilité de rédiger des ententes, voire de s'en soustraire éventuellement.
Comprendre le besoin de reconnaissance légale en matière de pluriparentalité : pistes de réflexion à partir des coparentalités gaies et lesbiennes
Authors: Herbrand Cathy
Published: April 2015

Si la question de la relation entre droit et pratiques se révèle souvent complexe et controversée, elle l'est particulièrement dans le cas de la reconnaissance légale de la pluriparentalité, c'est-à-dire des situations familiales dans lesquelles plus de deux adultes s'occupent d'un enfant à la manière de parents. Cet article vise à approfondir ce sujet à partir d'entretiens réalisés auprès de gais et lesbiennes vivant en Belgique et ayant eu recours à la coparentalité pour avoir un enfant. Ces projets de coparentalité constituent une porte d'entrée pertinente à cet égard puisqu'ils regroupent généralement plus de deux adultes qui collaborent et s'impliquent à des degrés divers vis-à-vis de l'enfant. Lorsque l'enfant a déjà une double filiation, il n'existe en Belgique aucune possibilité de reconnaitre légalement des figures parentales supplémentaires. L'étude de ces coparentalités permet dès lors d'interroger les difficultés qui continuent à persister au-delà de l'égalité de traitement et de mettre en avant la spécificité des besoins légaux qu'engendre ce type de situations familiales. Les propos recueillis montrent notamment la diversité des demandes en la matière, encourageant la mise en place d'un ensemble de mesures légales souples et variées.
Surrogates in Quebec: The Good, the Bad, and the Foreigner
Authors: Tremblay Régine
Published: April 2015

Quebec's legal regime for the establishment of parent-child relationships was substantially modified in 2002 in order to achieve equality. Reforms left untouched, however, an existing rule justified by women's equality: the absolute nullity of surrogacy agreements. The article shows how the rule has led judges to preclude the filiation of children born of surrogacy in certain situations and how it has forced judges to apply creative, albeit unpredictable, solutions in others. It explores the decisions of Quebec courts, through the portraits of surrogates traced in the decisions—the good, the bad, and the foreigner. The brief overview of cases exhibits how similar and different facts have an inconsistent impact on the ratios of the decisions. The weight given to some legal elements (the importance of the declaration and attestation of birth, the possibility of considering the consent of the father vitiated, the single surrogate versus the surrogate in a relationship, the civil status of the intended parents, and so on) to the detriment of others is problematized. The article depicts how labels and stereotypes predominate in legal reasoning when legal rules are not clear, creating problematic discourses about sensitive topics (womanhood and motherhood, children's rights, and sexual orientation).
Wärmebehandlung – Fehler, Schäden und Ursachen*
Authors: Sommer P.
Published: April 2015

Kurzfassung

Im Rahmen der Praktikerseminare des HärtereiKongresses 2014 wurden zahlreiche Schadensfälle an wärmebehandelten Bauteilen vorgestellt. Hierbei wurde aufgezeigt, dass zwar auch Wärmebehandlungsfehler zu Schäden führen, jedoch weitaus mehr Fehler dadurch verursacht werden, dass latent verborgene Fehler durch die Wärmebehandlung erst sichtbar werden bzw. erst bei der Fertigung nach der Wärmebehandlung oder durch fehlerhafte Einsatzbedingungen verursacht wurden. Eine Schadensanalyse erfordert nicht nur eine verlässliche Mess- und Untersuchungsmethodik, sondern auch umfassende Erfahrungen mit Werkstoffen, Wärmebehandlungsverfahren und Einsatzgebieten.
Numerische Optimierung des Aufkohlungsprozesses für funktionsbedingte Konstruktionsdetails von Stahlbauteilen*
Authors: Diemar A. , Hildebrand J. , Gerth U. , Könke C.
Published: April 2015

Kurzfassung

Funktionsbedingt sind an Stahlbauteilen bestimmte Konstruktionsdetails, wie Querbohrungen oder Wellenabsätze, nicht zu vermeiden. Infolge einer äußeren Beanspruchung führt deren Form zu lokalen Extremwerten des meist mehraxialen Spannungszustandes, welche dann versagensmaßgebend für das Gesamtstahlbauteil sind. Die Form der funktionsbedingten Konstruktionsdetails beeinflusst auch die Kohlenstoffaufnahme aus der Aufkohlungsatmosphäre sowie die weitere Diffusion des Kohlenstoffs im Stahlbauteil und somit charakteristische Zielgrößen des Aufkohlungsprozesses, wie den lokalen Randkohlenstoffgehalt und die lokale Aufkohlungstiefe im Bereich des Konstruktionsdetails. Die Analyse von Aufkohlungsvorgängen komplexer Bauteilgeometrien erfolgt durch numerische Methoden, wie die der Finiten Elemente. Wird die Finite-Elemente-Methode mit höherwertigen Lösungsverfahren für Optimierungsprobleme gekoppelt, ergeben sich erweiterte Möglichkeiten zur Anpassung des Randkohlenstoffgehaltes und der Aufkohlungstiefe auf die speziellen Erfordernisse funktionsbedingter Konstruktionsdetails
Phase transitions induced by severe plastic deformation: steady-state and equifinality
Authors: Straumal Boris B. , Kilmametov Askar R. , Ivanisenko Yulia , Mazilkin Andrei A. , Kogtenkova Olga A. , Kurmanaeva Lilia , Korneva Anna , Zięba Pawel , Baretzky Brigitte
Published: April 2015

During severe plastic deformation (SPD), a steady-state is usually reached after a certain value of strain (i. e. number of passes during equal-channel pressing or number of rotations during high pressure torsion). The structure and properties of a material in a steady state (including composition of phases) do not depend on those in the starting state before SPD. In other words they are equifinal, and the production of lattice defects is in dynamic equilibrium with defect elimination. Moreover, the SPD-treatment at ambient temperature T
SP
D = 300 K is frequently equivalent to the heat treatment at a certain elevated temperature T
eff > 300 K. For example, the composition of phases in Cu–Ni, Co–Cu and Nd–Fe–B-based alloys after high pressure torsion corresponds to the states at 200, 890 and 1 170 °C, respectively, and is rather insensitive to the high pressure torsion rate (between 0.2 and 2 rpm) and pressure (between 3 and 8 GPa).
Non-uniform sintering of yttria-stabilized zirconia powder compact
Authors: Hbaieb Kais
Published: April 2015

Sintering behavior in both axial and radial directions has been studied for both pure and doped 8 mol.% yttria stabilized zirconia (8YSZ) with different concentrations of lithium nitrate. Detailed measurements were conducted at different positions in radial and axial directions to study the spatial variation in sintering of the powder compact. Doping with lithium nitrate was used to study the effect of varying the sintering rate on the spatial variation of sintering. It was shown that variation in sintering strain in the axial direction is small, whereas a linear gradient is noticeable in the radial direction. The variation in radial strain peaks at relatively low strains (5 – 10 %) and reduces to a minimum at the end of sintering. Comparing average axial and radial strains showed that radial strain is consistently higher than axial strain, implying that sintering is anisotropic especially during the intermediate stage. Density is determined in two ways: (1) Calculated based on measured volumetric strain, (2) calculated assuming sintering is isotropic; the two quantities are compared. It is shown that density divergence can rise to as large as 15 % and nearly vanishes at the end of sintering.
Recovery, recrystallization and diffusion in cold-rolled Ni
Authors: Shepelenko Margarita , Klinger Leonid , Rabkin Eugen , Berner Alexander , Prokoshkina Daria , Reglitz Gerrit , Fiebig Jochen , Wilde Gerhard , Divinski Sergiy V.
Published: April 2015

Recovery and recrystallization processes in cold-rolled Ni are investigated. While recrystallization and grain growth at temperatures above 700 K lead to a significant (threefold) decrease in micro-hardness, recovery at 600 K is shown to cause a measurable micro-hardness increase. This increase in micro-hardness is confirmed by atomic force microscopy observations of Vickers indents, and it is correlated with the vacancy-annihilation peak of the calorimetric signal. Diffusion of impurity–vacancy complexes to the dislocation cores and the resulting pinning of dislocations are surmised to contribute to the measured micro-hardness increase. Self-diffusion along interfaces in cold-rolled and partially recrystallized Ni samples is measured employing the radiotracer serial sectioning technique. Diffusion rates similar to those of general high-angle grain boundaries in well-annealed coarse-grained Ni polycrystals are observed. The results imply that the diffusion rate along the stationary recrystallization front, i. e. the interfaces separating the recrystallized and the as-deformed regions of the material, is similar to that along a general high-angle grain boundary.
Effect of carbon nanotubes produced by using different methods on electrical and optical properties of zinc oxide–carbon nanotube composite
Authors: Guler Omer
Published: April 2015

In this study, carbon nanotubes, which were produced by using chemical vapour deposition and mechano-thermal methods, were combined with zinc oxide matrix at different ratios and the effects of the nanotubes on electrical and optical properties of zinc oxide were examined. It was observed that electrical conductivity of zinc oxide at room temperature increased with the increase in the reinforcement rate both in carbon nanotube reinforced samples produced by using chemical vapour deposition and those produced by using the mechano-thermal method. Carbon nano-tube reinforced samples produced by using chemical vapour deposition yielded relatively better results for the same reinforcement rate.
On sea-ice dynamical regimes in the Arctic Ocean
Authors: Lukovich J.V. , Hutchings J.K. , Barber D.G.
Published: April 2015

Central to an understanding of evolution in sea-ice characteristics in response to climate change is an understanding of sea-ice dynamics. In this study, we investigate regional differences in ice dynamics in the Beaufort Sea and High Arctic using high-frequency ice buoy (beacon) data deployed during the SEDNA and IPY-CFL field campaigns from spring 2007 to winter 2008. Examined in particular are scaling laws determined from absolute dispersion statistics. We create temporal scaling maps to determine whether distinct dynamical regimes can be identified with differing scaling properties. The results from this analysis provide an alternative characterization to changes in sea ice based on dynamics rather than concentration and thickness, and thus insight into, and improved understanding of, the connections between sea-ice drift and morphology.
A Retrospect on the Limits of Postcolonial Studies
Authors: Parry Benita
Published: April 2015

Benita Parry here examines the political horizons of postcolonial studies, arguing for the crucial role of Marxism in sustaining the revolutionary impetus of postcolonialist thought. Addressing the career of the late Edward W. Said, Parry points out that while Said's approach to criticism may initially have been philological, political purpose and direction were ‘thrust upon him’ through the situation of his native Palestine in the 1970s, together with the retreat from radicalism within academia. The Said of this period thus urged upon intellectuals the need to engage with injustice and oppression. Parry writes of Said's ‘circuitous journey’ that returned him, in his later works, to a critical approach that eschewed the political, and aimed to contain conflict through his notion of the ‘contrapuntal.’ While Said, with many postcolonial critics, did not subscribe to Marxism, Parry suggests that his work retained a thoughtful and complex respect for Marxists such as Lukács, Goldmann, Raymond Williams, and Adorno. For Parry, Said's repudiation of Marxism is ‘of a different order’ from that of other postcolonial critics who drag revolutionary figures such as Fanon and Gramsci into their own agenda by attempting to stabilise and attune their thought to the ‘centre-left’. Parry goes on to criticise the editors of The Postcolonial Gramsci, for positing Marxist thinking as a restricting framework from which the editors aim to liberate Gramsci's writing. For Parry, these reappraisals of revolutionary thinkers constitute a new form of recuperative criticism that she terms ‘the rights of misprision’. If this is a strategy for ‘draining Marxist and indeed all left thought of its revolutionary impulses and energies’, Parry insists, ‘it is one to be resisted and countered, not in the interests of a sterile rigour, but – in Benjamin's words – to rescue the past and the dead, and a tradition and its receivers, from being overpowered by conformism’.
An Evaluation of Patient Safety Event Report Categories Using Unsupervised Topic Modeling
Authors: Fong A. , Ratwani R.
Published: April 2015

Objective: Patient safety event data repositories have the potential to dramatically improve safety if analyzed and leveraged appropriately. These safety event reports often consist of both structured data, such as general event type categories, and unstructured data, such as free text descriptions of the event. Analyzing these data, particularly the rich free text narratives, can be challenging, especially with tens of thousands of reports. To overcome the resource intensive manual review process of the free text descriptions, we demonstrate the effectiveness of using an unsupervised natural language processing approach.

Methods: An unsupervised natural language processing technique, called topic modeling, was applied to a large repository of patient safety event data to identify topics, or themes, from the free text descriptions of the data. Entropy measures were used to evaluate and compare these topics to the general event type categories that were originally assigned by the event reporter.

Results: Measures of entropy demonstrated that some topics generated from the un-supervised modeling approach aligned with the clinical general event type categories that were originally selected by the individual entering the report. Importantly, several new latent topics emerged that were not originally identified. The new topics provide additional insights into the patient safety event data that would not otherwise easily be detected.

Conclusion: The topic modeling approach provides a method to identify topics or themes that may not be immediately apparent and has the potential to allow for automatic reclassification of events that are ambiguously classified by the event reporter.
10.3846/1648715X.2014.973925
Authors: SHI Song
Published: April 2015

This paper investigates tax inequities in assessed values and how these inequities in tax assessments affect house price indices using assessed values statistics. Using the unique rating valuation data from the top 10 cities of New Zealand during the period 1994–2009, it finds that house price measurements using the Sale Price Appraisal Ratio (SPAR) method have performed well compared to the repeated sales method suggested by Case and Shiller (1989) and the assessed values (AV) method proposed by Clapp and Giaccotto (1992). The presence of systematic estimated errors (both vertical and horizontal inequities) in assessed values posts a concern for house price measurements using assessed values statistics. In this situation, both the SPAR and AVmethods benefit from the law of compensation of errors by using all transaction data. A policy implication is that the SPAR model is a good choice when using assessed values to measure house price movements at frequent time intervals, in particular for small countries.
SYSTEMATIC ANALYSIS OF AFFORDABLE HOUSING DEVELOPMENT AND PRICING STRUCTURE IN SHENZHEN, CHINA
Authors: SING Chun Pong , LOVE Peter E. D. , FUNG Wing Hong , HE Yun Zi
Published: April 2015

As a result of urban housing reform in China, it has become increasingly difficult for low and middle income families to purchase a house. In response to the growing demand for affordable housing, the Chinese Government has developed a specific housing policy to enable families to purchase properties from the private sector. The pricing mechanism of such housing is completely based on the family affordability and the profit margin of developers. To ensure the provision of housing for low and middle-income families, the future trend of affordable housing prices has become a concern for developers, consumers and may adversely influence the implementation of the current national housing policy. In this paper a systematic analysis of affordable housing development and its pricing structure is undertaken for the city of Shenzhen. As information pertaining to the factors influencing house prices is imperfect, a Grey model, which requires a limited amount of data to reflect unknown behavior, is constructed to provide a forecast for affordable house pricing. The analysis indicates that the government should adjust their current affordable housing policy to accommodate the forecasted upward trend in house prices.
Risk of Overall and Site-specific Cancers in Behçet Disease: A Nationwide Population-based Study in Taiwan
Authors: Wang Li-Hui , Wang Wei-Ming , Hsu Sheng-Min , Lin Sheng-Hsiang , Shieh Chi-Chang
Published: April 2015

Objective.

The relationship between autoimmune disease and cancer is complex while large-scale epidemiological studies of cancer risk in Behçet disease (BD) have not been reported. Therefore, we conducted a nationwide population-based cohort study.

Methods.

By using the National Health Insurance Research Database of 23 million people in Taiwan, we identified 1314 new patients with BD without previous cancer from 2000–2009 as a cohort. Standardized incidence ratios (SIR) of overall and site-specific cancers in patients with BD in comparison with the general population were calculated from 2000–2011.

Results.

Among the 1314 patients with BD, 30 developed cancers (9 men and 21 women). In overall cancer risk analysis, patients with BD had a higher risk (SIR 1.5, 95% CI 1.03–2.11). Among them, female patients with BD (SIR 1.8, 95% CI 1.14–2.7), but not male patients with BD (SIR 1.08, 95% CI 0.53–1.98), have a higher risk of overall cancer. In site-specific cancer risk analysis, patients with BD had a higher risk of non-Hodgkin lymphoma (SIR 8.3, 95% CI 2.1–22.7), hematological malignancy (SIR 4.2, 95% CI 1.3–10.2), and female breast cancer (SIR 2.2, 95% CI 1.004–4.1). The cancer risk was highest within the first-year followup (SIR 2.7, 95% CI 1.3–5.1), with 75% of the hematological malignancies found within the first year.

Conclusion.

This nationwide cohort study of cancer risk in patients with BD provides important information about the relationship between BD and malignancies. The results can be useful for cancer surveys in the future.
Patient Information about Gout: An International Review of Existing Educational Resources
Authors: Johnston Megan E. , Treharne Gareth J. , Chapman Peter T. , Stamp Lisa K.
Published: April 2015

Objective.

Inadequate patient information about gout may contribute to poor disease outcomes. We reviewed existing educational resources for gout to identify strengths and weaknesses and compare resources cross-nationally.

Methods.

Content, readability, and dietary recommendations were reviewed using a sample of 30 resources (print and Web-based) from 6 countries.

Results.

More than half of the resources were written at a highly complex level. Some content areas were lacking coverage, including comorbidity risks, uric acid target levels, and continuing allopurinol during acute attacks.

Conclusion.

Our findings suggest significant room for improvement in gout patient educational resources, particularly regarding self-management.
Comparison of different dispersion evaluation methods and a case history with the inversion to a soil model, related admittance functions, and the prediction of train‐induced ground vibration
Authors: Auersch Lutz , Said Samir
Published: April 2015

Ground vibrations due to different technical sources are analysed in theory and experiment for the dispersion of Rayleigh waves and the admittance spectra. Both tasks are theoretically based on the same concept: The admittance function in frequency‐wavenumber domain yields the dispersion as its maxima, and the admittance function in space domain is obtained by integrating it over the wavenumbers. On the experimental side, many signal processing methods have been applied to many sites and have been developed by the authors in the last 35 years, i.e., time‐domain methods, including the cross‐correlation method, and frequency‐domain methods such as the spectral analysis of surface waves with two or multiple sensors, the wavenumber‐transform method, and the spatial autocorrelation method. All methods are presented by their basic formula and by at least one example site. Different sensor arrays and deterministic and stochastic sources have been tested for the spatial autocorrelation method and the wavenumber‐transform method at several sites. In addition, all frequency‐domain methods are presented for a specific layered site comparing their quality. The evaluated dispersion curves are very similar, but a somewhat higher frequency range has been found for the fastest method, i.e., the multi‐sensor spectral‐analysis‐of‐surface‐waves method. The theoretical solutions have been used for the inversion of the measured dispersion to the soil profile of the specific layered soil. The theoretical soil model has subsequently been used to predict the ground vibration spectra of hammer and railway excitation that exhibit a good agreement with the corresponding measurements. Thus, the contribution shows the benefit of active and passive seismic methods for the prediction of railway vibration, including a new version of the spatial autocorrelation method for technical vibrations. On the other hand, technical and namely railway vibrations are considered a seismic source for the exploration of near surface soils.
Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)
Authors: Chen Q. , Farmer D. K. , Rizzo L. V. , Pauliquevis T. , Kuwata M. , Karl T. G. , Guenther A. , Allan J. D. , Coe H. , Andreae M. O. , Pöschl U. , Jimenez J. L. , Artaxo P. , Martin S. T.
Published: April 2015

Abstract. Real-time mass spectra of the non-refractory species in submicron aerosol particles were recorded in a tropical rainforest in the central Amazon Basin during the wet season from February to March 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic material accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. There was insufficient ammonium to neutralize sulfate. In this acidic, isoprene-rich, HO2-dominant environment, positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the 99% of the variance in the signal intensities of the organic constituents. The first factor was identified as associated with regional and local pollution and labeled "HOA" for its hydrocarbon-like characteristics. A second factor was associated with long-range transport and labeled "OOA-1" for its oxygenated characteristics. A third factor, labeled "OOA-2," was implicated as associated with the reactive uptake of isoprene oxidation products, especially of epoxydiols to acidic haze, fog, or cloud droplets. A fourth factor, labeled "OOA-3," was consistent with an association with the fresh production of secondary organic material (SOM) by the mechanism of gas-phase oxidation of biogenic volatile organic precursors followed by gas-to-particle conversion of the oxidation products. The suffixes 1, 2, and 3 on the OOA labels signify ordinal ranking with respect to the extent of oxidation represented by the factor. The process of aqueous-phase oxidation of water-soluble products of gas-phase photochemistry might also have been associated to some extent with the OOA-2 factor. The campaign-average factor loadings had a ratio of 1.4:1 for OOA-2 : OOA-3, suggesting the comparable importance of particle-phase compared to gas-phase pathways for the production of SOM during the study period.
Numerical analysis of the primary processes controlling oxygen dynamics on the Louisiana shelf
Authors: Yu L. , Fennel K. , Laurent A. , Murrell M. C. , Lehrter J. C.
Published: April 2015

Abstract. The Louisiana shelf, in the northern Gulf of Mexico, receives large amounts of freshwater and nutrients from the Mississippi–Atchafalaya river system. These river inputs contribute to widespread bottom-water hypoxia every summer. In this study, we use a physical–biogeochemical model that explicitly simulates oxygen sources and sinks on the Louisiana shelf to identify the key mechanisms controlling hypoxia development. First, we validate the model simulation against observed dissolved oxygen concentrations, primary production, water column respiration, and sediment oxygen consumption. In the model simulation, heterotrophy is prevalent in shelf waters throughout the year, except near the mouths of the Mississippi and Atchafalaya rivers, where primary production exceeds respiratory oxygen consumption during June and July. During this time, efflux of oxygen to the atmosphere, driven by photosynthesis and surface warming, becomes a significant oxygen sink. A substantial fraction of primary production occurs below the pycnocline in summer. We investigate whether this primary production below the pycnocline is mitigating the development of hypoxic conditions with the help of a sensitivity experiment where we disable biological processes in the water column (i.e., primary production and water column respiration). With this experiment we show that below-pycnocline primary production reduces the spatial extent of hypoxic bottom waters only slightly. Our results suggest that the combination of physical processes (advection and vertical diffusion) and sediment oxygen consumption largely determine the spatial extent and dynamics of hypoxia on the Louisiana shelf.