bluuebunny/crossref_metadata_2025_split huggingface dataset:
Food Insecurity and Conflict Events in Africa
Authors: Murshed Syed Mansoob , Badiuzzaman Muhammad , Hasan Rashel 
Published: May 2018

Abstract
The aim of this paper is to examine the relationship between food insecurity and conflict events short of war in Africa, taking account of a host of mediating factors, including the degree of inequality, the level of development, democratic quality, quality of governance and the degree of government expenditure, which we incorporate into our analysis. Our results suggest that food price volatility does contribute significantly to conflict events measured by political events in Africa (ACLED). Greater democracy can engender more conflict, but in a non-linear fashion. The broader V-DEM participatory index of democracy also encourages more protest. Our governance variables are significant, emphasising the salience of state capacity in this regard. An innovation of our study is the inclusion of inequality. We deploy two metrics of vertical inequality: the GINI coefficient and the broader V-DEM egalitarian index. The GINI index of income inequality has a counter-intuitive statistically insignificant sign, suggesting that greater income equality or middle-class share of income results in greater political unrest. We also utilise political measures of inter-group horizontal inequality which significantly engender conflict risk.
Movement Activity Among Patients Diagnosed with Alcohol Dependence Syndrome
Authors: Zawadzka Magdalena , Dziedziczak-Buczyńska Maria , Buczyński Andrzej , Henrykowska Gabriela 
Published: May 2018

Abstract
Frequent consumption of large amounts of alcohol usually does not correspond to regular physical activity. However, regular physical activity can lead to an improved well-being and greater satisfaction with life. The aim of the study was to determine the level of physical activity in the group of patients diagnosed with alcohol dependence syndrome and examine the correlation between these variables. The study was conducted among a selected group of individuals of both sexes, aged 22-65 and undergoing treatment. Our study indicated an absence of a correlation between gender and the level of physical activity among people addicted to alcohol. Moreover, no statistically significant relationship was found between alcohol dependence and physical activity undertaken in the researched group.
A molecular modeling study for miscibility of polyimide/polythene mixing systems with/without compatibilizer
Authors: Chen Song , Li Jian , Wei Lei , Jin Yongliang , Khosla Tushar , Xiao Jun , Cheng Bingxue , Duan Haitao 
Published: May 2018

Abstract
Molecular models were established to predict the miscibility of polyimide/polythene mixing systems and the enhancing effects of compatibilizer addition of maleic anhydride grafted polythene (MAH-g-PE). Molecular dynamics simulations were applied to investigate radial distribution functions and Flory-Huggins parameters of the mixing systems. Results show that polyimide/polythene is miscible to a certain degree, and the miscibility gets better after adding MAH-g-PE. Dissipative particle dynamics (DPD) simulations display that micro-phase separation occurs in the polyimide/polythene mixing systems, however, effective interfaces appear between polyimide and polythene phases after adding MAH-g-PE. The results of molecular mechanics simulations indicate that the ability of mixing systems to resist stretch, compression and shear deformation increases after adding MAH-g-PE. This work offers a promising technique to predict miscibility properties for polyimide/polythene system prior to actual production and attempt to find a suitable compatibilizer for that system.
Tempest: Temporal Dynamics in Anonymity Systems
Authors: Wails Ryan , Sun Yixin , Johnson Aaron , Chiang Mung , Mittal Prateek 
Published: May 2018

Abstract
Many recent proposals for anonymous communication omit from their security analyses a consideration of the effects of time on important system components. In practice, many components of anonymity systems, such as the client location and network structure, exhibit changes and patterns over time. In this paper, we focus on the effect of such temporal dynamics on the security of anonymity networks. We present Tempest, a suite of novel attacks based on (1) client mobility, (2) usage patterns, and (3) changes in the underlying network routing. Using experimental analysis on real-world datasets, we demonstrate that these temporal attacks degrade user privacy across a wide range of anonymity networks, including deployed systems such as Tor; pathselection protocols for Tor such as DeNASA, TAPS, and Counter-RAPTOR; and network-layer anonymity protocols for Internet routing such as Dovetail and HORNET. The degradation is in some cases surprisingly severe. For example, a single host failure or network route change could quickly and with high certainty identify the client’s ISP to a malicious host or ISP. The adversary behind each attack is relatively weak – generally passive and in control of one network location or a small number of hosts. Our findings suggest that designers of anonymity systems should rigorously consider the impact of temporal dynamics when analyzing anonymity.
Secure asymmetry and deployability for decoy routing systems
Authors: Bocovich Cecylia , Goldberg Ian 
Published: May 2018

Abstract
Censorship circumvention is often characterized as a cat-and-mouse game between a nation-state censor and the developers of censorship resistance systems. Decoy routing systems offer a solution to censor- ship resistance that has the potential to tilt this race in the favour of the censorship resistor by using real connections to unblocked, overt sites to deliver censored content to users. This is achieved by employing the help of Internet Service Providers (ISPs) or Autonomous Systems (ASes) that own routers in the middle of the net- work. However, the deployment of decoy routers has yet to reach fruition. Obstacles to deployment such as the heavy requirements on routers that deploy decoy router relay stations, and the impact on the quality of service for customers that pass through these routers have deterred potential participants from deploying existing systems. Furthermore, connections from clients to overt sites often follow different paths in the upstream and downstream direction, making some existing designs impractical. Although decoy routing systems that lessen the burden on participating routers and accommodate asymmetric flows have been proposed, these arguably more deployable systems suffer from security vulnerabilities that put their users at risk of discovery or make them prone to censorship or denial of service attacks. In this paper, we propose a technique for supporting route asymmetry in previously symmetric decoy routing systems. The resulting asymmetric solution is more secure than previous asymmetric proposals and provides an option for tiered deployment, allowing more cautious ASes to deploy a lightweight, non-blocking relay station that aids in defending against routing-capable adversaries. We also provide an experimental evaluation of relay station performance on off-the-shelf hardware and additional security improvements to recently proposed systems.
“Won’t Somebody Think of the Children?” Examining COPPA Compliance at Scale
Authors: Reyes Irwin , Wijesekera Primal , Reardon Joel , On Amit Elazari Bar , Razaghpanah Abbas , Vallina-Rodriguez Narseo , Egelman Serge 
Published: May 2018

Abstract
We present a scalable dynamic analysis framework that allows for the automatic evaluation of the privacy behaviors of Android apps. We use our system to analyze mobile apps’ compliance with the Children’s Online Privacy Protection Act (COPPA), one of the few stringent privacy laws in the U.S. Based on our automated analysis of 5,855 of the most popular free children’s apps, we found that a majority are potentially in violation of COPPA, mainly due to their use of thirdparty SDKs. While many of these SDKs offer configuration options to respect COPPA by disabling tracking and behavioral advertising, our data suggest that a majority of apps either do not make use of these options or incorrectly propagate them across mediation SDKs. Worse, we observed that 19% of children’s apps collect identifiers or other personally identifiable information (PII) via SDKs whose terms of service outright prohibit their use in child-directed apps. Finally, we show that efforts by Google to limit tracking through the use of a resettable advertising ID have had little success: of the 3,454 apps that share the resettable ID with advertisers, 66% transmit other, non-resettable, persistent identifiers as well, negating any intended privacy-preserving properties of the advertising ID.
Toward Distribution Estimation under Local Differential Privacy with Small Samples
Authors: Murakami Takao , Hino Hideitsu , Sakuma Jun 
Published: May 2018

Abstract
A number of studies have recently been made on discrete distribution estimation in the local model, in which users obfuscate their personal data (e.g., location, response in a survey) by themselves and a data collector estimates a distribution of the original personal data from the obfuscated data. Unlike the centralized model, in which a trusted database administrator can access all users’ personal data, the local model does not suffer from the risk of data leakage. A representative privacy metric in this model is LDP (Local Differential Privacy), which controls the amount of information leakage by a parameter ∈ called privacy budget. When ∈ is small, a large amount of noise is added to the personal data, and therefore users’ privacy is strongly protected. However, when the number of users ℕ is small (e.g., a small-scale enterprise may not be able to collect large samples) or when most users adopt a small value of ∈, the estimation of the distribution becomes a very challenging task. The goal of this paper is to accurately estimate the distribution in the cases explained above. To achieve this goal, we focus on the EM (Expectation-Maximization) reconstruction method, which is a state-of-the-art statistical inference method, and propose a method to correct its estimation error (i.e., difference between the estimate and the true value) using the theory of Rilstone et al. We prove that the proposed method reduces the MSE (Mean Square Error) under some assumptions.We also evaluate the proposed method using three largescale datasets, two of which contain location data while the other contains census data. The results show that the proposed method significantly outperforms the EM reconstruction method in all of the datasets when ℕ or ∈ is small.
Undermining Privacy in the Aircraft Communications Addressing and Reporting System (ACARS)
Authors: Smith Matthew , Moser Daniel , Strohmeier Martin , Lenders Vincent , Martinovic Ivan 
Published: May 2018

Abstract
Despite the Aircraft Communications, Addressing and Reporting System (ACARS) being widely deployed for over twenty years, little scrutiny has been applied to it outside of the aviation community. Whilst originally utilized by commercial airlines to track their flights and provide automated timekeeping on crew, today it serves as a multi-purpose air-ground data link for many aviation stakeholders including private jet owners, state actors and military. Such a change has caused ACARS to be used far beyond its original mandate; to date no work has been undertaken to assess the extent of this especially with regard to privacy and the various stakeholder groups which use it. In this paper, we present an analysis of ACARS usage by privacy sensitive actors-military, government and business. We conduct this using data from the VHF (both traditional ACARS, and VDL mode 2) and satellite communications subnetworks. Based on more than two million ACARS messages collected over the course of 16 months, we demonstrate that current ACARS usage systematically breaches location privacy for all examined aviation stakeholder groups, explaining the types of messages used to cause this problem.We illustrate the challenges with three case studies-one for each stakeholder group-to show how much privacy sensitive information can be constructed with a handful of ACARS messages. We contextualize our findings with opinions on the issue of privacy in ACARS from 40 aviation industry professionals. From this, we explore recommendations for how to address these issues, including use of encryption and policy measures.
Privacy Pass: Bypassing Internet Challenges Anonymously
Authors: Davidson Alex , Goldberg Ian , Sullivan Nick , Tankersley George , Valsorda Filippo 
Published: May 2018

AbstractThe growth of content delivery networks (CDNs) has engendered centralized control over the serving of internet content. An unwanted by-product of this growth is that CDNs are fast becoming global arbiters for which content requests are allowed and which are blocked in an attempt to stanch malicious traffic. In particular, in some cases honest users-especially those behind shared IP addresses, including users of privacy tools such as Tor, VPNs, and I2P - can be unfairly targeted by attempted ‘catch-all solutions’ that assume these users are acting maliciously. In this work, we provide a solution to prevent users from being exposed to a disproportionate amount of internet challenges such as CAPTCHAs. These challenges are at the very least annoying and at their worst - when coupled with bad implementations - can completely block access from web resources. We detail a 1-RTT cryptographic protocol (based on an implementation of an oblivious pseudorandom function) that allows users to receive a significant amount of anonymous tokens for each challenge solution that they provide. These tokens can be exchanged in the future for access without having to interact with a challenge. We have implemented our initial solution in a browser extension named “Privacy Pass”, and have worked with the Cloudflare CDN to deploy compatible server-side components in their infrastructure. However, we envisage that our solution could be used more generally for many applications where anonymous and honest access can be granted (e.g., anonymous wiki editing). The anonymity guarantee of our solution makes it immediately appropriate for use by users of Tor/VPNs/ I2P. We also publish figures from Cloudflare indicating the potential impact from the global release of Privacy Pass.
Consistent Synchronous Group Off-The-Record Messaging with SYM-GOTR
Authors: Schliep Michael , Vasserman Eugene , Hopper Nicholas 
Published: May 2018

Abstract
We describe SYM-GOTR, a protocol for secure Group Off-The-Record (GOTR) messaging. In contrast to previous work, SYM-GOTR is the first protocol to offer confidential, authenticated, and repudiable conversations among a dynamic group with the additional properties of message unlinkability and the guarantee that all users see the same conversation, while providing efficient use of network and CPU resources. SYM-GOTR achieves these properties through the use of a novel optimistic consistency check protocol that either determines that all users agree on a transcript with constant-size messages or identifies at least one user that has not followed the protocol. We provide an implementation of SYM-GOTR as a Java library along with a plugin for the Jitsi instant messaging client. We analyze the performance of SYM-GOTR in a real world deployment scenario and discuss the challenges of providing a usable implementation without compromising the security of the conversation.
Noise-robust assessment of SNP array based CNV calls through local noise estimation of log R ratios
Authors: Cosemans Nele , Claes Peter , Brison Nathalie , Vermeesch Joris Robert , Peeters Hilde 
Published: May 2018

Abstract
Arrays based on single nucleotide polymorphisms (SNPs) have been successful for the large scale discovery of copy number variants (CNVs). However, current CNV calling algorithms still have limitations in detecting CNVs with high specificity and sensitivity, especially in case of small (<100 kb) CNVs. Therefore, this study presents a simple statistical analysis to evaluate CNV calls from SNP arrays in order to improve the noise-robustness of existing CNV calling algorithms. The proposed approach estimates local noise of log R ratios and returns the probability that a certain observation is different from this log R ratio noise level. This probability can be triggered at different thresholds to tailor specificity and/or sensitivity in a flexible way. Moreover, a comparison based on qPCR experiments showed that the proposed noise-robust CNV calls outperformed original ones for multiple threshold values.
The Rescaled VAR Model with an Application to Mixed-Frequency Macroeconomic Forecasting
Authors: Giusto Andrea , İşcan Talan B. 
Published: May 2018

AbstractThis paper introduces the rescaled representation of VAR models (R-VARs) and demonstrates its application in forecasting mixed-frequency macroeconomic data. We develop the model, illustrate how to implement it, and derive the asymptotic properties of the estimates. We show that R-VARs provide reliable estimates of the prediction error bands while maintaining the precision of the point forecasts. We illustrate these features by comparing it to a mixed-frequency Bayesian VAR model, the leading alternative in the existing literature.
Bayesian Subset Selection for Two-Threshold Variable Autoregressive Models
Authors: Ni Shuxia , Xia Qiang , Liu Jinshan 
Published: May 2018

Abstract
In this paper, we propose and study an effective Bayesian subset selection method for two-threshold variable autoregressive (TTV-AR) models. The usual complexity of model selection is increased by capturing the uncertainty of the two unknown threshold levels and the two unknown delay lags. By using Markov chain Monte Carlo (MCMC) techniques with driven by a stochastic search, we can identify the best subset model from a large number of possible choices. Simulation experiments show that the proposed method works very well. As applied to the application to the Hang Seng index, we successfully distinguish the best subset TTV-AR model.
Charakterisierung einer Modenverwirbelungskammer als Testumgebung für drahtlose Sensor/Aktor-Module
Authors: Cammin Christoph , Krush Dmytro , Heynicke Ralf , Scholl Gerd 
Published: May 2018

Zusammenfassung
Dieser Beitrag beschreibt Messungen zur Charakterisierung einer Modenverwirbelungskammer vor dem Hintergrund der Qualifizierung von drahtlosen Sensor/Aktor-Modulen. Aufbauend auf Normen bzw. Testempfehlungen, die für andere drahtlose Anwendungen entwickelt wurden, wird in diesem Beitrag das Verhalten einer Modenverwirbelungskammer unter verschiedenen Beladungen und jeweils verschiedenen Modenrührersequenzen speziell für den Test von drahtlosen Sensor/Aktor-Modulen in industriellen Indoor-Umgebungen untersucht. Im Abschluss wird unter Abwägung der Wirtschaftlichkeit eine Konfiguration der Modenverwirbelungskammer für entsprechende Testmessungen vorgeschlagen.
Effect of Variable Geometry Guide-Vane with Cylindrical Endwalls on Turbine Stage Performance
Authors: Jiang Yuting , Wan Xinchao , Yue Guoqiang , Lin Hongfei , Zheng Qun 
Published: May 2018

AbstractThe part-load performance of gas turbine is of great importance due to the consideration of running time spent at part power, and Variable Geometry Turbine (VGT) is an important way to meet the requirements. Effect of variable geometry guide-vane with cylindrical endwalls on part-load turbine stage performance is quantified by detailed analysis of aerodynamic characteristics. The turbine stage characteristics of corrected mass flow, corrected output power and efficiency are presented to investigate the VGT performance under the condition of four off-design rotating angles. In addition, the flow field, the loss distribution and the leakage flow are analyzed for different rotating angles. Results show that both the corrected mass flow and the corrected output power increase as the vane throat area is increased, the total leakage area and the shroud area are increased with the increase of rotating angle, whereas the hub leakage area is decreased, and the total pressure loss and the entropy change of variable geometry vane are both increased with the decrease of vane throat area.
A Climate for Change? Norwegian Farmers’ Attitudes to Climate Change and Climate Policy
Authors: Brobakk Jostein 
Published: May 2018

Abstract
Climate change is one of the major challenges of our time, and particularly so for agriculture. Agriculture is a significant contributor to climate change and, according to projections from the Intergovernmental Panel on Climate Change (IPCC), will experience alterations in production conditions in the future. The Norwegian government’s 2009 White Paper on climate policy for agriculture is based on the point of view that the agricultural sector can and should contribute to Norway fulfilling its climate policy commitments. This requires changes in farm operations and production methods, making the farmer an important agent when it comes to the implementation of climate change mitigation measures. In this article, I study Norwegian farmers’ climate change perceptions and priorities, and examine what it would take for them to consider implementing mitigation measures on their own farms. The analysis is based on a survey focusing on climate change from a representative sample of Norwegian farmers in 2011, the only survey of its kind conducted on this group so far. The results show that even if farmers perceive climate change as real and manmade, they do not appear to experience the changes as requiring immediate action. Moreover, farmers seem to view adapting to new environmental policy as a greater challenge than adapting to climate change itself. Farmers also appear to place production-related goals and managing the farm economy higher on the agenda than curbing emissions. Financial incentives, in the form of public support schemes or higher prices for food produced in a more environmentally friendly way, are factors which could increase the likelihood of implementing environmental measures on their own farms. A majority of farmers also believe that sectors other than agriculture should contribute more to cuts in greenhouse gases. Factors that most clearly explain the variation in attitudes to climate change are education levels, political or ideological factors, and the feeling of proximity; that is to say, to what extent one perceives climate change to be something that will affect one’s own productivity in the future. In order to fulfill environmental policy commitments in the agricultural sector, farmers’ motivation must be strengthened, and the focus should be placed on measures that view productivity goals, farm economies and mitigation measures in a wider context.
Analyzing Electoral Behavior Using PTV’s: Benefits and Methodological Issues
Authors: Ramonaitė Ainė 
Published: May 2018

Abstract
In the last decade, the propensity-to-vote (PTV) measure is being increasingly used in the research of electoral behavior. The purpose of this article is to explore the advantages and methodological issues of this measure, applying it for the analysis of the determinants of party choice in the 2016 Lithuanian parliamentary elections. In particular, the article explores the implications of using OLS regression for analysing a generic party with a stacked data matrix instead of cross-classified multilevel modeling.