bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Performance Enhancement Scheme for Doubly-Fed Induction Generator-Based Wind Power Systems under Voltage Sags and Swells
Authors: Das Tapash , Zhang Jingxin , Pota Hemanshu
Published: July 2017

Wind power is a major contributor in the renewable energy sector but it faces some issues regarding modern grid-code compliance. Popular wind power systems based on Doubly-Fed Induction Generators (DFIG) need additional protection under grid voltage disturbances. They also need to support the grid voltage under such transient occurrences. This paper presents a novel performance enhancement scheme for DFIGs subjected to symmetrical and asymmetrical voltage sags and swells at the Point of Common Coupling (PCC). The scheme comprises a protection system and a reactive power management system working simultaneously under the command of a supervisory control system. The protection system protects the DFIG converter by limiting the overcurrent in the Rotor Side Converter (RSC) of the DFIG and keeping the dc-link capacitor voltage within an acceptable range; whereas, the reactive power management supports the grid voltage by either injecting or absorbing reactive power to reduce the magnitude of voltage sags and swells. It is found that the performance of the DFIG wind generation system improves significantly under the proposed scheme. A grid-connected 9-MW DFIG wind farm is used for simulation in MATLAB/Simscape Power Systems.
English, motility and Ismaili transnationalism
Authors: Bolander Brook
Published: July 2017

The transnational Ismaili community is made up of local communities of Ismailis living in over 25 countries around the world. Despite diversity within and between these communities, the 2.5–12 million Ismailis worldwide share a common identity as Ismaili. Various structures and resources are used to construct and maintain the community. These include an official language – English. In this article, I aim to explore the role of English in connection with Ismaili transnationalism. Drawing on ethnographic data collected during fieldwork in Northern Pakistan and Eastern Tajikistan, and on data taken from digital spaces, I will focus on the movement of local Ismailis away from Northern Pakistan and Eastern Tajikistan, and on the movement of people and ideas to Northern Pakistan and Eastern Tajikistan. I will thereby argue for the importance of including non-mobile individuals in conceptualizations of Ismaili transnationalism. In doing so, I will apply the concept of “motility”, which points to interconnections between social and spatial mobility, and highlights the potential for mobility; and I will underline the role local settings play for transnational processes. In the course of the article, I also demonstrate that Ismaili transnationalism is not homogeneous. Instead, certain people, places and spaces emerge as more relevant to its construction and maintenance. This becomes coupled with access to English and has implications for this issue’s focus on the relationship between South and Central Asian spaces.
Social Transfers and Income Inequality in Bulgaria
Authors: Mihaylova Svilena , Bratoeva-Manoleva Silviya
Published: July 2017

The paper analyzes the distributional effects of social transfers in Bulgaria in the period 2000-2014, using income inequality decomposition by factor components. The results suggest that social transfers mitigate income inequality, but this effect varies depending on the type of transfer. Pensions exert the strongest influence due to their significant share in total income, which also rises over time. Family allowances are pro-poor in nature, but because of their small share in beneficiaries’ total income, their impact on overall inequality is much weaker. “Other social benefits” have the weakest inequality-reducing effect, which is due to their higher concentration towards the richest decile and increasing share in total income. Despite the inequality-decreasing impact of social transfers, we argue that they should not be regarded as the sole remedy for the sharp income disparities in the country, but need to be accompanied by relevant active labor market policies.
Is Real Depreciation or More Government Deficit Expansionary? The Case of Slovenia
Authors: Hsing Yu
Published: July 2017

The purpose of this paper is to examine the impacts of the real exchange rate, the government deficit and other relevant variables on aggregate output in Slovenia. Few of the previous studies have applied the AD/AS model to examine the impacts of major macroeconomic variables on aggregate output. This paper makes contributions to the literature by applying a rigorous model to examine how real GDP is affected by the real exchange rate, fiscal policy and other related variables. The exponential GARCH model is applied in empirical work. The paper finds that real depreciation of the Euro may affect Slovenia’s aggregate output positively or negatively and that more central government deficit as a percent of GDP does not affect aggregate output. In addition, Slovenia’s aggregate output is positively associated with the real stock price, the real oil price and real total labor cost or wage and is negatively influenced by the real lending rate and the expected inflation rate. Recent real depreciation of the Euro would help Slovenia’s aggregate output whereas expansionary fiscal policy would not be effective in stimulating the economy.
Evaluating the Use of Personal Networks to Circumvent Formal Processes: A Case Study ofVruzkiin Bulgaria
Authors: Williams Colin C. , Yang Junhong
Published: July 2017

The aim of this paper is to evaluate the prevalence and distribution of the use of personal connections to circumvent formal procedures by soliciting favours for and from others, known as vruzki, and how this can be explained and tackled. Reporting data from 2,005 face-to-face interviews conducted in late 2015 in Bulgaria, the finding is that 30 per cent of respondents had used vruzki in the 12 months prior to the survey, particularly when accessing medical services and finding a job. Estimating a logit model and then calculating the marginal effects, the population groups significantly more likely to have used vruzki are those whose norms, values and beliefs are not in symmetry with the formal laws and regulations, perceiving the penalties and detection risks as higher, those reporting their financial situation as very comfortable, and the highest income groups, but also younger people, the unemployed, and those living in larger households. The paper concludes by discussing the theoretical and policy implications along with the future research required.
The Unemployed Workers’ Perceptions of Stress and Employment Prospects in Macedonia: The Role of Alternative Adjustment Mechanisms
Authors: Nikoloski Dimitar , Pechijareski Ljupcho
Published: July 2017

Depressed labour market conditions in Macedonia manifested by high and persistent unemployment rate, strong segmentation and prevailing long-term unemployment is considered as a heritage of more than two decades long period of transition. Unemployment has a number of negative consequences such a decreased income which is assumed to influence the subjective experience of unemployment. The negative macroeconomic shocks in Macedonia have been mitigated due to the strengthened role of alternative labour market adjustment mechanisms such as: employment in the informal sector, emigration and inactivity. However, their impact on the unemployed workers’ perceptions of stress and future labour market prospects is less clear-cut. In this paper we use results from a survey carried out on a sample of unemployed workers in Macedonia in order to identify the psychological implications of unemployment by assessing the perceived stress and employment prospects with particular reference to the role of alternative labour market adjustment mechanisms.
Portfolio Diversification in the South-East European Equity Markets
Authors: Zaimovic Azra , Arnaut-Berilo Almira , Mustafic Arnela
Published: July 2017

Diversification potential enables investors to manage their risk and decrease risk exposure. Good diversification policy is a safety net that prevents a portfolio from losing its value. A well-diversified portfolio consists of different categories of property with low correlations, while highly correlated markets have the feature of low possibilities for diversification. The biggest riddle in the world of investments is to find the optimal portfolio within a set of available assets with limited capital. There are numerous studies and mathematical models that deal with portfolio investment strategies. These strategies take advantage of diversification by spreading risk over several financial assets. Modern portfolio theory seeks to find the optimal model with the best results. This paper tries to identify relationships between returns of companies traded in South-East European equity markets. A Markowitz mean-variance (MV) portfolio optimization method is used to identify possibilities for diversification among these markets and world leading capital markets. This research also offers insight into to the level of integration of South-East European equity markets. Principal component analysis (PCA) is used to determine components that describe the strong patterns and co-movements of the dataset. Finally, we combined MV efficient frontier and equity, which represent PCA components, to draw conclusions. Our findings show that PC analysis substantially simplifies asset selection process in portfolio management. The results of the paper have practical applications for portfolio investors.
Perceived Quality and Corporate Image in Mobile Services: The Role of Technical and Functional Quality
Authors: Babic-Hodovic Vesna , Arslanagic-Kalajdzic Maja , Imsirpasic Amina
Published: July 2017

The purpose of this study is to assess the technical (output) and functional (process) quality of mobile services, as well as the role of corporate image as a mediator between technical/functional quality perceptions and overall quality assessment of mobile services. Grönroos’s service quality model is used as the conceptual base of the study. Technical quality was operationalized through two sub-dimensions: baseline network quality and augmented technical quality. The SERVPERF framework was used in the operationalization of the functional quality. A quantitative survey was conducted with (n = 414) customers of the telecommunication operator in B&H. The results suggest that corporate image mediates the effects of (1) two functional quality dimensions (tangibles and assurance) and (2) both technical quality dimensions on the overall service quality assessment. The core technical quality dimension (network) is also directly related to overall service quality perception. A discussion of the results and their implications for theory and practice is then presented.
Current mode pulse width modulation/pulse position modulation based on phase lock loop
Authors: Wisartpong Pichet , Silaphan Vorapong , Kurutach Sunee , Wardkein Paramote
Published: July 2017

In this paper, the fully integrated CMOS current mode PLL with current input injects at the place of input or output of the loop filter without summing amplifier circuit. It functions as PPM and PWM circuit is present. In addition, its frequency response is an analysis which electronic tuning BPF and LPF are obtained. The proposed circuit has been designed with 0.18 μm CMOS technology. The simulation results of this circuit can be operated at 2.5 V supply voltage, at center frequency 100 MHz. The linear range of input current can be adjusted from 43 μA to 109 μA, and the corresponding duty cycle of pulse width output is from 93% to 16% and the normalized pulse position is from 0.93 to 0.16. The power dissipation of this circuit is 4.68 mW with the total chip area is 28 μm × 60 μm.
Novel single-phase five-level inverter utilizing digital counter control scheme
Authors: Nwosu Cajethan M. , Umeogamba Anthony I. , Ogbuka Cosmas U.
Published: July 2017

A novel single-phase digital control circuit-based five level inverter (FLI) is presented in this paper. Based on the determined switching angle, one switching cycle of the inverter is divided into segments from which the switching sequence of the inverter switches is digitized. A programmed counter built aroundJ−Kflip flops with logic gates provided the needed switching signals for theH-bridge inverter. Proposed inverter is verified through simulation in a MATLAB/SIMULINK environment and simulation results are given. Simulation results show notable reduction in total harmonic distortion (THD) in the inverter output voltage and load current. With an RL load (of 200 Ω and 0.250H), a single digit THD of 8.5 1% for the inverter load current is realized. Comparison of the novel control circuit-dependent FLI with the conventional and contemporary power-circuit-dependent cascadedH-bridge inverter (CHBI) show that the novel FLI is synthesized with lesser number of power circuit and control circuit components.
The analysis of output voltage distortion of inverter for frequency lower than the nominal
Authors: Bartman Jacek
Published: July 2017

The paper discussed the studies related to the output voltage distortion of frequency inverter depending on its frequency. The changes in the effective value of voltage, THD, harmonics and interharmonics were presented for three different frequencies, lower than 50Hz. Additionally, it was shown how these values change depending on measurement time, presenting waveforms cycle by cycle in graphs, averaged in 10 periods and averaged in 150 periods of the analyzed signal. The studies were conducted in the laboratory area equipped with power quality meter class A.
Wheat water use and yield under different salinity of irrigation water
Authors: Abedinpour Meysam
Published: July 2017

A field experiment was conducted for determination of crop coefficient (KC) and water stress coefficient (Ks) for wheat crop under different salinity levels, during 2015–2016. Complete randomized block design of five treatments were considered, i.e., 0.51 dS·m−1 (fresh water, FW) as a control treatment and other four saline water treatments (4, 6, 8 and 10 dS·m−1), for S1, S2, S3 and S4 with three replications. The results revealed that the water consumed by plants during the different crop growth stages follows the order of FW > S1 > S2 > S3 > S4 salinity levels. According to the obtained results, the calculated values of KC significantly differed from values released by FAO paper No 56 for the crops. The Ks values clearly differ from one stage to another because the salt accumulation in the root zone causes to reduction of total soil water potential (Ψt), therefore, the average values of water stress coefficient (Ks) follows this order; FW(1.0) = S1(1.0) > S2(1.0) > S3(0.93) > S4(0.82). Precise data of crop coefficient, which is required for regional scale irrigation management is lacking in developing countries. Thus, the estimated values of crop coefficient under different variables are essential to achieve the best management practice (BMP) in agriculture.
Influence of extraneous waters on the quality and loads of pollutants in wastewater discharged into the treatment plant
Authors: Kaczor Grzegorz B. , Chmielowski Krzysztof , Bugajski Piotr
Published: July 2017

The aim of the study was to analyze an influence of an inflow penetrating into two selected small sewerage systems during a rainy weather on pollutant concentration and load in raw sewage. Studies were conducted in 2010–2015 on two small sewerage systems in Małopolska province. The studies confirmed that the inflow penetrating into the sewerage systems resulted in a decrease of pollutant concentrations in sewage. However, they also showed that this dilution was not constant for all types of pollutants. The most important outcome of the study was demonstrating that despite its diluting effect on pollutants, the intense inflow into a sewerage system resulted in an increase of a sewage pollutant load. This increase was not regular, but it was rising dramatically when the inflow share in sewage exceeded 50%. The study indicated that the inflow penetrating into the sewerage system should not be disregarded, as it actually presented a significant threat to the wastewater treatment process and in consequence to the quality of recipient waters.
The effects of uninsulated sewage tanks on groundwater. A case study in an eastern Hungarian settlement
Authors: Mester Tamás , Szabó György , Bessenyei Éva , Karancsi Gergő , Barkóczi Norbert , Balla Dániel
Published: July 2017

In our study we attempt to demonstrate the effects of uninsulated sewage tanks, which are the most important sources of contamination in settlements without sewage systems, on groundwater quality. We compared the results of measurements carried out before and one and a half years after the construction of the sewage system. We established 3 m deep monitoring wells within a 25 m radius of a sewage tank, which were then sampled, and the level of groundwater was recorded. The 3D model constructed on the basis of the saturated zone shows that the effluent wastewater formed a groundwater level dome with a height of more than 1 m. After the sewage tank was taken out of use the difference between the highest and lowest groundwater levels decreased to a few centimetres. In our study we investigated the spatial distribution of NH4+(ammonium). Using the 3D model we were able to precisely determine the volume of water bodies with different levels of contamination. In an approximately 25 m3water body, in the immediate environment of a sewage tank in use we detected NH4+at a concentration which was characteristic of undiluted wastewater (>90 mg·dm−3). After the sewage tank was taken out of use, the concentration in its immediate environment decreased by more than 50%, although almost everywhere in the modelled area concentrations were measured above the limit value. Based on the above, we can conclude that the cleaning process has started, but the complete decontamination of the groundwater will take several years.
Surface water resources of small agricultural watershed in the Kujawy region, central Poland
Authors: Miatkowski Zygmunt , Smarzyńska Karolina
Published: July 2017

The goal of the paper was to determine surface water resources of an agricultural watershed representative for the areas of intensive crop production in the Kujawy region. This area is characterised by the lowest average annual precipitation in Poland and high water demands related to the intensive crop production.

Hydrological studies were carried out in 2007–2011 in the upper Zgłowiączka River watershed located in the eastern part of the analysed region. Over 90% of the study area is used as an arable land.

Water velocity in the river bed and water level were measured at the outlet of the watershed in the river cross-section Samszyce.

The upper Zgłowiączka River has a snow-rainfall hydrological regime, strongly modified by anthropogenic activities related to the intensive crop production and installation of subsurface drainage system. The study period was characterised by very large temporal variability of hydrological conditions. The mean annual outflow coefficient amounted to 18% and varied highly in time: from 3% in the average years to 62% in the abnormally wet 2011. Average discharge (SSQ) in the Samszyce river cross-section was equal to 0.25 m3·s−1, and the mean unit outflow – to 3.2 dm3·s−1·km−2. The results of the study show that disposable surface water resources of the Kujawy region are very small, especially in the summer half-year. Thus, their utilization as a potential source of water for crop irrigation can be taken into account only, if water excesses will be retained within the watershed and used in conjunction with groundwater resources.
The Power to Judge, the Power to Act: the Argentine Supreme Court as a Policymaker
Authors: Campora Mario
Published: July 2017

Even though the role of courts to enforce economic, social and cultural rights through structural remedies is well established, the implementation stage of rulings following successful litigation seems to be an area of research still in the making. In the Global South, certain constitutional courts have taken on such litigation as a way to advance economic and social rights. The Judiciary Power thus became a key actor in the framing and execution of public policies. This paper examines how the Argentine Supreme Court has intervened after 2001 in public policies regarding the enforcement of social security, environmental and human rights.
Copy-verb constructions in Tibeto-Burman and beyond
Authors: Ozerov Pavel , Daudey Henriëtte
Published: July 2017

The subject of this study is the copy-verb construction {
Past–future asymmetries in time adverbials and adpositions: A crosslinguistic and diachronic perspective
Authors: Herce Borja
Published: July 2017

Expressions like English
Do grammatical relations reflect information status? Reassessing Preferred Argument Structure theory against discourse data from Tondano
Authors: Brickell Timothy C. , Schnell Stefan
Published: July 2017

We test Preferred Argument Structure theory against corpus data from Tondano, an Austronesian language with symmetrical voice. Investigating the use of full noun phrases in individual argument positions, we find no significant clustering of both S and P as opposed to A, hence no discourse ergativity. Moreover, neither pivotal nor non-pivotal grammatical relations appear to specialise in the accommodation of full noun phrases. Thus, grammatical relations do not serve as architecture for regulating information flow in discourse. Only constituent order reflects information flow, so that full noun phrases tend to occur in clause-final position. More generally, correlations of humanness and topicality predict most straightforwardly attested patterns of argument realisation.
Influence of Bi3+content on photoluminescence of InNbO4:Eu3+,Bi3+for white light-emitting diodes
Authors: Tang An , Gu Liduo , Shao Fengxiang , Liu Xidong , Zhao Yongtao , Chen Haijun , Zhang Hongsong
Published: July 2017

A series of red-emitting phosphors InNbO4:Eu3+,Bi3+was prepared by a high temperature solid-state reaction. The structure, size distribution and luminescence properties of the phosphors were respectively characterized by X-ray diffraction (XRD), laser particle size and molecular fluorescence spectrometer. The XRD results indicate that the phase-pure samples have been obtained and the crystal structure of the host has not changed under the Eu3+and Bi3+co-doping. The test of size distribution shows that the phosphor has a normal size distribution. The excitation spectra illustrate that the dominant sharp peaks are located at 394 nm (7F0→5L6) and 466 nm (7F0→5D2). Meanwhile, the emission spectra reveal that the phosphors excited by the wavelength of 394 nm or 466 nm have an intense red-emission line at 612 nm owing to the5D0→7F2transition of Eu3+. Bi3+doping has not changed the peak positions except the photoluminescence intensity. The emission intensity is related to Bi3+concentration, and it is up to the maximum when the Bi3+-doping concentration is 4 mol%. Due to good photoluminescence properties of the phosphor, the InNbO4:0.04Eu3+,0.04Bi3+may be used as a red component for white light-emitting diodes.
Pattern formation in the nonlinear Schrödinger equation with competing nonlocal nonlinearities
Authors: Maucher F. , Pohl T. , Krolikowski W. , Skupin S.
Published: July 2017

We study beam propagation in the framework of the nonlinear Schrödinger equation with competing Gaussian nonlocal nonlinearities. We demonstrate that such system can give rise to self-organization of light into stable states of trains or hexagonal arrays of filaments, depending on the transverse dimensionality. This long-range ordering can be achieved by mere unidirectional beam propagation. We discuss the dynamics of long-range ordering and the crucial role which the phase of the wavefunction plays for this phenomenon. Furthermore we discuss how transverse dimensionality affects the order of the phasetransition.
Recent progress in Pancharatnam–Berry phase optical elements and the applications for virtual/augmented realities
Authors: Lee Yun-Han , Tan Guanjun , Zhan Tao , Weng Yishi , Liu Guigeng , Gou Fangwang , Peng Fenglin , Tabiryan Nelson V. , Gauza Sebastian , Wu Shin-Tson
Published: July 2017

In this review paper,we report recent progress on Pancharatnam-Berry (PB) phase optical elements, such as lens, grating, and deflector. PB lenses exhibit a fast switching time between two or more focal lengths with large diopter change and aperture size, which is particularly attractive for addressing the accommodation mismatch in head-mounted display devices. On the other hand, PB gratings and deflectors offer a large-angle beam deflection with wide acceptance cone and high efficiency, as compared to conventional volume gratings. Such merits provide great advantages for waveguide-coupling augmented reality headsets. Moreover, the thickness of PB optical elements is only a few micrometers, thus they can be conveniently integrated into modern wearable display systems.
Factors Affecting Students’ Privacy Paradox and Privacy Protection Behavior
Authors: Weinberger Maor , Bouhnik Dan , Zhitomirsky-Geffet Maayan
Published: July 2017

In this exploratory study, we investigate the factors affecting two opposite types of online privacy behavior: 1) online privacy paradox, i.e. a mismatch between users’ online privacy attitudes and their online privacy behavior; and 2) online privacy protection. To assess these two types of behavior, we devised a new direct scale comprising 25 items explicitly highlighting benefits and risks of the examined behavior. Various factors related to online privacy and anonymity were considered in light of the existing theories on online privacy behavior. To this end, 169 students from different fields of study in Israeli academia were administered closed-ended questionnaires. The multivariate linear regression analysis showed that information science students had a significantly lower tendency toward privacy paradox behavior compared to other students. In addition, we found that as the participants’ privacy concern and online privacy self efficacy increase, their tendency toward privacy paradox behavior decreases. However, surprisingly, there was no significant association between privacy protection behavior and high technical skills or online privacy literacy. This research has social implications for academia and the general public, as it shows that the protection of online privacy does not depend on technical knowledge or complicated tool usage, but rather can be achieved by raising users’ online privacy concern and self-efficacy.
The place of the “quantitative signature symbols” in the classification of the cartographic presentation methods
Authors: Korycka-Skorupa Jolanta , Pasławski Jacek
Published: July 2017

The authors of the article pay their attention to the lack of a generally accepted classification of the cartographic presentation methods. The classification, which was described in the Ratajski’s handbook (1989) in the mostly extensive way, is commonly used in the Polish literature. According to the authors, it would be appropriate to modify one of the types of symbols (quantitative ones) as an independent method of data presentation at the quantitative level, in addition to the method of diagram, choropleth, dot method and isoline one.
Research on identification method of heavy vehicle rollover based on hidden Markov model
Authors: Zhao Zhiguo , Wang Yeqin , Hu Xiaoming , Tao Yukai , Wang Jinsheng
Published: July 2017

Aiming at the problem of early warning credibility degradation as the heavy vehicle load and its center of gravity change greatly; the heavy vehicle rollover state identification method based on the Hidden Markov Model (HMM, is introduced to identify heavy vehicle lateral conditions dynamically in this paper. In this method, the lateral acceleration and roll angle are taken as the observation values of the model base. The Viterbi algorithm is used to predict the state sequence with the highest probability in the observed sequence, and the Markov prediction algorithm is adopted to calculate the state transition law and to predict the state of the vehicle in a certain period of time in the future. According to combination conditions of Double lane change and steering, applying Trucksim and Matlab trained hidden Markov model, the model is applied to the online identification of heavy vehicle rollover states. The identification results show that the model can accurately and efficiently identify the vehicle rollover state, and has good applicability. This study provides a novel method and a general strategy for active safety early warning and control of vehicles, which has reference significance for the application of the Hidden Markov theory in collision, rear-end and lane departure warning system.
Seismic stability of the survey areas of potential sites for the deep geological repository of the spent nuclear fuel
Authors: Kaláb Zdeněk , Šílený Jan , Lednická Markéta
Published: July 2017

This paper deals with the seismic stability of the survey areas of potential sites for the deep geological repository of the spent nuclear fuel in the Czech Republic. The basic source of data for historical earthquakes up to 1990 was the seismic website [10]. The most intense earthquake described occurred on September 15, 1590 in the Niederroesterreich region (Austria) in the historical period; its reported intensity is Io = 8-9. The source of the contemporary seismic data for the period since 1991 to the end of 2014 was the website [11]. It may be stated based on the databases and literature review that in the period from 1900, no earthquake exceeding magnitude 5.1 originated in the territory of the Czech Republic.

In order to evaluate seismicity and to assess the impact of seismic effects at depths of hypothetical deep geological repository for the next time period, the neo-deterministic method was selected as an extension of the probabilistic method. Each one out of the seven survey areas were assessed by the neo-deterministic evaluation of the seismic wave-field excited by selected individual events and determining the maximum loading.

Results of seismological databases studies and neo-deterministic analysis of Čihadlo locality are presented.
Wiretapping End-to-End Encrypted VoIP Calls: Real-World Attacks on ZRTP
Authors: Schürmann Dominik , Kabus Fabian , Hildermeier Gregor , Wolf Lars
Published: July 2017

Voice calls are still one of the most common use cases for smartphones. Often, sensitive personal information but also confidential business information is shared. End-to-end security is required to protect against wiretapping of voice calls. For such real-time communication, the ZRTP key-agreement protocol has been proposed. By verbally comparing a small number of on-screen characters or words, called Short Authentication Strings, the participants can be sure that no one is wiretapping the call. Since 2011, ZRTP is an IETF standard implemented in several VoIP clients.

In this paper, we analyzed attacks on real-world VoIP systems, in particular those implementing the ZRTP standard. We evaluate the protocol compliance, error handling, and user interfaces of the most common ZRTP-capable VoIP clients. Our extensive analysis uncovered a critical vulnerability that allows wiretapping even though Short Authentication Strings are compared correctly. We discuss shortcomings in the clients’ error handling and design of security indicators potentially leading to insecure connections.
Hardening Stratum, the Bitcoin Pool Mining Protocol
Authors: Recabarren Ruben , Carbunar Bogdan
Published: July 2017

Stratum, the de-facto mining communication protocol used by blockchain based cryptocurrency systems, enables miners to reliably and efficiently fetch jobs from mining pool servers. In this paper we exploit Stratum’s lack of encryption to develop passive and active attacks on Bitcoin’s mining protocol, with important implications on the privacy, security and even safety of mining equipment owners. We introduce StraTap and ISP Log attacks, that infer miner earnings if given access to miner communications, or even their logs. We develop BiteCoin, an active attack that hijacks shares submitted by miners, and their associated payouts. We build BiteCoin on WireGhost, a tool we developed to hijack and surreptitiously maintain Stratum connections. Our attacks reveal that securing Stratum through pervasive encryption is not only undesirable (due to large overheads), but also ineffective: an adversary can predict miner earnings even when given access to only packet timestamps. Instead, we devise Bedrock, a minimalistic Stratum extension that protects the privacy and security of mining participants. We introduce and leverage the mining cookie concept, a secret that each miner shares with the pool and includes in its puzzle computations, and that prevents attackers from reconstructing or hijacking the puzzles.

We have implemented our attacks and collected 138MB of Stratum protocol traffic from mining equipment in the US and Venezuela. We show that Bedrock is resilient to active attacks even when an adversary breaks the crypto constructs it uses. Bedrock imposes a daily overhead of 12.03s on a single pool server that handles mining traffic from 16,000 miners.
Detecting Anti Ad-blockers in the Wild
Authors: Mughees Muhammad Haris , Qian Zhiyun , Shafiq Zubair
Published: July 2017

The rise of ad-blockers is viewed as an economic threat by online publishers who primarily rely on online advertising to monetize their services. To address this threat, publishers have started to retaliate by employing anti ad-blockers, which scout for ad-block users and react to them by pushing users to whitelist the website or disable ad-blockers altogether. The clash between ad-blockers and anti ad-blockers has resulted in a new arms race on the Web. In this paper, we present an automated machine learning based approach to identify anti ad-blockers that detect and react to ad-block users. The approach is promising with precision of 94.8% and recall of 93.1%. Our automated approach allows us to conduct a large-scale measurement study of anti ad-blockers on Alexa top-100K websites. We identify 686 websites that make visible changes to their page content in response to ad-block detection. We characterize the spectrum of different strategies used by anti ad-blockers. We find that a majority of publishers use fairly simple first-party anti ad-block scripts. However, we also note the use of third-party anti ad-block services that use more sophisticated tactics to detect and respond to ad-blockers.
Palatalisation in Dublin Irish, or How to Speak Irish with a Dublin Accent
Authors: Snesareva Marina
Published: July 2017

This paper focuses on palatalisation in Irish spoken by Dublin-based bilinguals with English as their first language. As opposed to previous researches in Irish phonetics and phonology, this study examines new speakers of Irish, whose speech was recorded in November 2014. All informants were born and raised in Dublin, lived either in the city or in the neighbouring counties and demonstrated sufficient fluency in Irish, i.e. had no problems with reading, could actively participate in conversation and give detailed answers without switching to English. Computer analysis of their data has shown that even though in traditional Irish dialects palatalisation is not position-bound, there is a correlation between palatalisation of a consonant and its neighbouring vowel quality in the speech of Dublin bilingualsdue to English influence andother factors.
Spectrally Perron Polynomials and the Cauchy-Ostrovsky Theorem
Authors: Paparella Pietro
Published: July 2017

In this note, we simplify the statements of theorems attributed to Cauchy and Ostrovsky and give proofs of each theorem via combinatorial and nonnegative matrix theory. We also show that each simple sufficient condition in each statement is also necessary in its respective case. In addition, we introduce the notion of a spectrally Perron polynomial and pose a problem that appeals to a wide mathematical audience.
Insight into the Fulnek Church and Parish Medieval Building Chronology
Authors: Augustinková Lucie , Klima Alice
Published: July 2017

The church of the Holy Trinity and parish in Fulnek was for nearly four centuries an Augustinian canonry and collegiate church (1293-1389). The medieval church and parish building chronology, however, have not been thus far established. From research between 2015 and 2016 we have been able to identify medieval portions of the buildings, clarify the site medieval construction phases and date the parish buildings (formerly the canonry) from dendrochronological analysis of embedded wooden scaffolding.
Optimization of Single-Layer Braced Domes
Authors: Grzywiński Maksym
Published: July 2017

The paper deals with discussion of optimization problem in civil engineering structural space design. Minimization of mass should satisfy the limit state capacity and serviceability conditions. The cross-sectional areas of bars and structural dimensions are taken as design variables. Variables are used in the form of continuous and discrete. The analysis is done using the Structural and Design of Experiments modules of Ansys Workbench v17.2. As result of the method a mass reduction of 46,6 % is achieved.
Estimating Design Resistance of Wrought Balcony Girders
Authors: Jung Karel , Marková Jana , Sýkora Miroslav
Published: July 2017

The contribution is focused on reliability of balcony girders of a Czech national heritage monument. As preliminary reliability assessment suggests insufficient resistance, a series of nondestructive tests supplemented by a single tensile test are performed and evaluated by the statistical methods. Values of material properties, recommended in standards for historic materials, seem to be overly conservative and it is advised to specify properties of historic metallic materials by tests.
Sustainability of Street Space in Built-Up Territory in the Case of Barrier-Free Use
Authors: Kocurová Petra , Bílková Alžběta
Published: July 2017

The street space is perceived as the multi-element dynamic public space. A diverse group of users with the often conflicting requirements is intertwined with it. To ensure the adequate utilization and hence its sustainability, it is essential to predict these claims for the future users in the already designed public spaces. However, in the already built-up area these tools reduce problems and increase the functionality of a limited area. The recovery by the creation of a functionally stable environment (safety, clarity, accessibility, attractiveness) for all user groups in urban settlements and creates a pleasant place to stay, work, live and relax. One of the risky groups with the specific requirements for the use of a public space are the people with limited mobility. This group is often physically or mentally disadvantaged in the comparison to the others. In the solution of a street area we have to deal with structural modifications to ensure an independent movement and orientation, for people with limited mobility or vision. Especially for blind and partially sighted people it is necessary to know and respect the principles and techniques of a spatial orientation. The environment which is created by construction has to produce information in sufficient quantities and quality adequate, so that street space is seen as a collection of various points, lines and characters for visually impaired people who would choose the indicatively important phenomena. The rules of barrier-free use, although legally binding, are in many cases incorrectly applied in practice. Nescience of these principles, their poor application and intensity of spatial orientation in urban environment often leads to disorientation for these users, the feeling of psychological isolation and often to the accidents. The article focuses on solving the existing street space in cities in a relation to the barrier-free use.
Probability and Sensitivity Nonlinear Analysis of the Hermetic Cover of Main Shut-off Valve under Extreme Pressure and Temperature
Authors: Králik Juraj
Published: July 2017

This paper describes the probabilistic nonlinear analysis of the containment hermetic cover of main shut-off valve (MSV) under an extreme internal overpressure and temperature. The scenario of the hard accident in NPP and the methodology of the calculation of the fragility curve of the failure overpressure using the probabilistic safety assessment PSA 2 level are presented. The elasto-plastic behavior of steel material dependent on temperature was considered in software ANSYS. The method of central composite design sampling (CCD) of the response surface methodology (RSM) was used to probability and sensitivity analysis of the hermetic cover reliability.
Shrinkage, Weight Loss and Fracture Parameters of Selected Polymer-Modified Cement Mortars During Ageing
Authors: Kucharczyková Barbara , Šimonová Hana , Keršner Zbyněk , Kocáb Dalibor
Published: July 2017

Results of pilot experiments focused on monitoring of shrinkage, weight loss and mechanical fracture properties of two selected polymer-modified cement mortars (PCM) during their aging are presented in the paper. Comparison of the measurement results was carried out on the test specimens at the age of 3, 28, and 90 days. The results show that even the specimens made from PCMs, for which the manufacturer declares no shrinkage, shrank considerably. The results also show that the development of mechanical fracture parameters during ageing of these materials differs from generally expected trends and thus the monitoring of these parameters is recommended.
On the Influence of the Interaction Laws of a Dynamical Particle System for Sample Optimization
Authors: Mašek Jan , Vořechovský Miroslav
Published: July 2017

The presented paper investigates the effect of the formulation of the energy potential of a dynamical particle system used for the optimization of statistical point sampling. The dynamical particle system, originally developed as a physical analogy to the Audze-Eglajs (AE) optimization criterion and its periodical modification (PAE), effectively demonstrated that the originally proposed energy potential performs well only in poorly applicable scenarios featuring low-dimensional design domains filled with a rather high number of design points. A remedy is presented which involves a refined formulation of the energy potential, as well as its derivation. The reasoning behind this approach is also dealt with in detail.
Uncertainty in Crack width Estimates According to Fib Model Code 2010
Authors: Mlčoch Jan , Marková Jana , Sýkora Miroslav
Published: July 2017

The contribution is focused on quantifying model uncertainty of crack width estimates for reinforced concrete beams. Predictions obtained by the model provided by the fib Model Code 2010 are compared with results of tests of beams having different longitudinal and shear reinforcement ratios and concrete cover. Trends of model uncertainty with basic variables are investigated.
Pistola Finca Pinos: ferramenta ou arma de fogo?
Authors: Garrido Rodrigo Grazinoli , Dias Leonardi Armenia Cristina
Published: July 2017

O artigo pretende analisar a possibilidade de uso da ferramenta denominada “pistola finca pinos”, utilizada na construção civil, como arma de fogo na execução de crimes contra a vida. Serão examinados os tipos, as características e o mecanismo de funcionamento da pistola finca pinos e munição associada, em comparação às características da arma de fogo, com o objetivo de avaliar sua possível aplicação na prática de crime. Serão verificadas as normas regulamentadoras da venda e manuseio dessa ferramenta, assim como a análise de alguns casos de mortes decorrentes do uso da pistola finca pinos e a diagnose diferencial conferida a cada caso: homicídio, suicídio ou acidente.
Suicídio atípico com dois ou mais disparos efetivos de arma de fogo: casuística do Instituto Médico Legal de Belo Horizonte e implicações periciais
Authors: Bordoni Leonardo Santos , Medeiros Ana Flávia Dias , Da Silva Ana Paula Nogueira , Crivellaro Andreia Gonçalves , Grossi Laysa Oliveira , Trindade Marcella Pedrosa , Bordoni Polyanna Helena Coelho
Published: July 2017

O Brasil ocupou o oitavo lugar em números absolutos de suicídios no mundo em 2012. Apesar do suicídio com arma de fogo (AF) não ser a modalidade mais comum, é frequente seu encontro na prática pericial criminal. Na maioria dos suicídios com AF há apenas um disparo efetivo e o encontro de duas ou mais lesões de entrada classifica o suicídio como atípico. Neste estudo foram avaliados os suicídios atípicos com dois ou mais disparos efetivos de AF nas necropsias do Instituto Médico Legal de Belo Horizonte realizadas entre 2006 e 2012. Foram resgatados cinco casos, correspondendo a 2,63% do total de suicídios com AF autopsiados no período estudado. A maioria dos casos era do sexo masculino, solteira, tinha pele morena, apresentava idade média de 42,3 anos e recebeu atendimento médico previamente ao óbito. Em quatro casos foram observadas duas lesões de entrada de projéteis de AF e em apenas um foram observadas três. Todos apresentavam lesões de entrada no tórax, a maioria localizada na região peitoral esquerda. Em dois indivíduos houve lesões de entrada no tórax e na cabeça. A causa da morte da maioria foi traumatismo torácico perfuro-contuso. Apesar da necropsia forense ser crucial no estabelecimento da causa médica da morte e na avaliação da capacidade de desempenhar atos motores voluntários após um primeiro disparo, a investigação criminal de casos de suicídios atípicos é um trabalho multidisciplinar, onde cada uma das peças periciais deve se encaixar adequadamente para o estabelecimento correto da causa jurídica da morte.
Cross reaction and forensic comparison of blood testing done by private and public sector laboratories
Authors: Stadler Christian , Dias Filho Claudemir Rodrigues , Roca Maria Gabriela
Published: July 2017

Blood evidence consists of one of the most important forensic pieces. However, it is not always easy to identify a stain as blood. The best and fastest way of doing so, is by using rapid screening derived from immunochromatographic tests to spot hemoglobin. However, cross reaction between species might be an issue since hemoglobin of other animals could be present, especially considering crimes against fauna, outdoor crime scenes with an easy access for animals, and human and domestic animal trauma cases. According to the particular structure in each country there are private and/or public laboratories working in this field. Methods and resources from private and public sectors are different, and procedures also differ from country to country. The main objective of our work was to validate the presence of human blood using interspecific samples and the criteria defined by each lab using rapid blood detection test kits from the public sector related to forensic analysis in Brazil and from the private sector in Germany. As a secondary goal, we have evaluated sensibility, the Hook Effect and pH effect in some commercially available kits. Our results showed that the tests carried out are suitable for the detection of human blood in forensic samples using methods commonly employed in the public and private sectors.