Showing papers on "Proxy (statistics) published in 2016"

Cognitive reserve and cognitive function in healthy older people: a meta-analysis

Abstract: The associations between proxy measures of cognitive reserve (CR) and cognition vary across studies and cognitive domains. This meta-analysis aimed to assess the relationship between CR and cognition in multiple domains (memory, executive function, visuospatial ability, and language). CR was considered in terms of three key proxy measures – educational level, occupational status, and engagement in cognitively stimulating activities – individually and in combination. One-hundred and thirty-five studies representing 128,328 participants were included. Of these, 109 used a measure of education, 19 used a measure of occupation, 31 used a measure of participation in cognitively stimulating activities, and 6 used a combination of these. All three proxy measures had a modest positive association with cognition; occupational status and cognitive activities showed the most variation across cognitive domains. This supports the view that the commonly used proxy measures of CR share an underlying process but that eac...

Does Turnover Intention Matter? Evaluating the Usefulness of Turnover Intention Rate as a Predictor of Actual Turnover Rate

Abstract: Turnover research has traditionally examined intention to turnover rather than actual turnover. Such studies assume that leave intent serves equally well as both a proxy for and predictor of employ...

The Role of Proxy Advisory Firms: Evidence from a Regression-Discontinuity Design

Abstract: Proxy advisory firms have become important players in corporate governance, but the extent of their influence over shareholder votes is debated. We estimate the effect of Institutional Shareholder Services (ISS) recommendations on voting outcomes by exploiting exogenous variation in ISS recommendations generated by a cutoff rule in ISS voting guidelines. Using a regression discontinuity design, we find that from 2010 to 2011, a negative ISS recommendation on a say-on-pay proposal leads to a 25 percentage point reduction in say-on-pay voting support, suggesting a strong influence over shareholder votes. We also use our setting to examine the informational role of ISS recommendations.Received April 13, 2015; editorial decision June 13, 2016 by Editor Itay Goldstein.

On varieties of doubly robust estimators under missingness not at random with a shadow variable.

Abstract: Suppose we are interested in the mean of an outcome variable missing not at random. Suppose however that one has available a fully observed shadow variable, which is associated with the outcome but independent of the missingness process conditional on covariates and the possibly unobserved outcome. Such a variable may be a proxy or a mismeasured version of the outcome and is available for all individuals. We have previously established necessary and sufficient conditions for identification of the full data law in such a setting, and have described semiparametric estimators including a doubly robust estimator of the outcome mean. Here, we propose two alternative estimators, which may be viewed as extensions of analogous methods under missingness at random, but enjoy different properties. We assess the correctness of the required working models via straightforward goodness-of-fit tests.

Anonymous attribute-based proxy re-encryption for access control in cloud computing

Abstract: As a public key cryptographic primitive, attribute-based encryption ABE is promising in implementing fine-grained access control in cloud computing. However, before ABE comes into practical applications, two challenging issues have to be addressed, that is, users' attribute privacy protection and access policy update. In this paper, we tackle the aforementioned challenge for the first time by formalizing the notion of anonymous ciphertext-policy attribute-based proxy re-encryption anonymous CP-ABPRE and giving out a concrete construction. We propose a novel technique called match-then-re-encrypt, in which a matching phase is additionally introduced before the re-encryption phase. This technique uses special components of the proxy re-encryption key and ciphertext to anonymously check whether the proxy can fulfill a proxy re-encryption or not. Theoretical analysis and simulation results demonstrate that our anonymous CP-ABPRE scheme is secure and efficient. Copyright © 2016 John Wiley & Sons, Ltd.

Product Design Awards and The Market Value of The Firm

Abstract: Product design has increasingly been recognized as an important source of competitive advantage. This study empirically estimates the impact of effective design on the market value of the firm. We use a firm's receipt of a product design award as a proxy for its design effectiveness. Based on data from 264 announcements of design awards given to commercialized products between 1998 and 2011, we find that award announcements are associated with statistically significant positive stock market reactions. Depending on the benchmark model used to estimate the stock market reaction, the market reaction over a two-day period (the day of announcement and the preceding day) ranges from 0.95% to 1.02%. The market reaction is more positive for smaller firms and for firms whose award winning products are consumer goods. However, a firm's growth potential, industry competitiveness, and whether a firm is a first time or repeated award winner do not significantly affect the market reaction.

Comparison of Measured and Proxy-Based VS30 Values in California

Abstract: This study was prompted by the recent availability of a significant amount of openly accessible measured VS30 values and the desire to investigate the trend of using proxy-based models to predict V...

Orthorexia nervosa by proxy

Abstract: In 1997 the US physician Steven Bratman called “health food junkies” some individuals led to consequences detrimental to health by dietary rules intended to promote health and introduced the term “orthorexia”. Three passages of Bratman’s article may be significant and expressive: “As often happens, my sensitivity to the problem of orthorexia comes through personal experience. I myself passed through a phase of extreme dietary purity (...) too often patient and alternative practitioner work together to create an exaggerated focus on food (...) a novel eating disorder, for which (I) have coined the name orthorexia nervosa”[1]. Orthorexia is a neologism coined from the Greek (ὀρθóς, right and ὄρεξις, appetite). The term literally means ‘correct appetite’ but it is used to indicate ‘healthy eating’. Orthorexia nervosa (ON) is an expression modeled on anorexia nervosa to indicate a possible new eating disorder [2]. A growing number of PubMed articles contain the word orthorexia in the title (Fig. 1). However, at the present time ON is not recognized as an official psychiatric diagnosis and is not mentioned in DSM5 as an autonomous eating disorder [3]. As regards psychometric instruments the Bratman Orthorexia Test (BOT) [2] and the ORTO-15 [4] were the first tools aimed to identify orthorectic attitudes. Both revealed some flaws [5, 6] and a revision of ORTO-15 is in progress. Point prevalence rates of ON are especially variable which is mainly due to the above-mentioned absence of detailed diagnostic criteria shared by the scientific community. In 2016 Dunn and Bratman proposed two main diagnostic criteria for ON [7] that are summarized in Table 1. The proposal is a constructive first step, but at present we do not have robust evidence of its reliability and validity. A noteworthy fact is that body image disturbance and body weight concerns are not required for this diagnosis. However, the following features are often associated with orthorectic attitudes in the literature and in the clinical practice: sense of physical impurity due to incorrect food choice; persistent belief that dietary practices are healthpromoting despite significant medical complications and evidence of malnutrition. Assuming that ON is an autonomous syndrome, should these features be included among the diagnostic criteria? Should the insight (good, poor, absent) be specified? Should the possible presence of medical complications and/or malnutrition be used to specify different severity levels? Further work is needed to define reliable and valid diagnostic criteria and psychometric tools for ON. In 1998 Gerald Russell et al. [8] described some mothers with anorexia nervosa who underfed their children but the authors did not use the expression anorexia nervosa (AN) by proxy that had been introduced 13 years before. After the 1985 article [9] some other scientific papers have depicted cases or discussed the concept of AN by proxy [10–15]. On the contrary, till now no scientific study has been devoted to a condition that could be called orthorexia nervosa by proxy: i.e., a person with ON who is obsessed The authors contributed equally to this work.

Attractive Female Romantic Partners Provide a Proxy for Unobservable Male Qualities: The When and Why Behind Human Female Mate Choice Copying

Abstract: Previous research indicates that women find men more desirable when they appear to be desired by other women than in the absence of such cues—an effect referred to as female mate choice copying. Fe...

Proxy SVARs: Asymptotic Theory, Bootstrap Inference, and the Effects of Income Tax Changes in the United States

Abstract: Proxy structural vector autoregressions (SVARs)identify structural shocks in vector autoregressions (VARs) with external proxy variables that are correlated with the structural shocks of interest but uncorrelated with other structural shocks. We provide asymptotic theory for proxy SVARs when the VAR innovations and proxy variables are jointly a-mixing. We also prove the asymptotic validity of a residual-based moving block bootstrap (MBB) for inference on statistics that depend jointly on estimators for the VAR coeffcients and for covariances of the VAR innovations and proxy variables. These statistics include structural impulse response functions (IRFs). Conversely, wild bootstraps are invalid, even when innovations and proxy variables are either independent and identically distributed or martingale difference sequences, and simulations show that their coverage rates for IRFs can be badly mis-sized. Using the MBB to re-estimate confidence intervals for the IRFs in Mertens and Ravn (2013), we show that inferences cannot be made about the effects of tax changes on output, labor, or investment.

Does Common Analyst Coverage Explain Excess Comovement

Abstract: This article shows that correlated errors in news about fundamentals are an important, rational determinant of excess comovement. Individual analysts’ forecast errors tend to be correlated across stocks. Using a proxy for correlated forecast errors based on analyst coverage, I find that stocks with similar sets of analysts exhibit more excess comovement, controlling for industry and other variables. Exogenous changes in commonality in analyst coverage around i) brokerage firm mergers and ii) additions to an index lead to changes in excess comovement. This information channel explains 10% to 25% of the increase in comovement around additions to the S&P 500 index.

Detection of proxy server

Abstract: Devices, systems, and methods of detecting whether an electronic device or computerized device or computer, is communicating with a computerized service or a trusted server directly and without an intermediary web-proxy, or indirectly by utilizing a proxy server or web-proxy. The system searches for particular characteristics or attributes, that characterize a proxy-based communication session or channel and that do not characterize a direct non-proxy-based communication session or channel; or conversely, the system searches for particular characteristics or attributes, that characterize a direct non-proxy-based communication session or channel and that do not characterize a proxy-based communication session or channel; and based on these characteristics, determines whether or not a proxy server exists and operates.

A Key-Policy Attribute-Based Proxy Re-Encryption Without Random Oracles

Abstract: 1College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China 2Centre for Computer and Information Security Research (CCISR), School of Computing and Information Technology, University of Wollongong, Wollongong, Australia 3School of Computer and Software, Nanjing University of Information Science, Nanjing, China ∗Corresponding author: wsusilo@uow.edu.au

Confidence-based authentication discovery for an outbound proxy

Abstract: A confidence-based authentication discovery scheme is implemented at a proxy. The scheme assumes that some level of unauthenticated browsing is allowed prior to enforcing authentication at the proxy. Once a known and trusted set of identity providers has been accessed and the user is required to authenticate at the proxy (e.g., as a result of policy), the proxy initiates Federated Single Sign-On (F-SSO) to one or more (or, preferably, all) known sites accessed by the browser. This F-SSO operation is performed seamlessly, preferably without the user's knowledge (after the user allows an initial trust decision between the proxy acting as a service provider and the external identity provider). The proxy collates the results and, based on the trust it has with those sites, produces a confidence score. That score is then used as input into policy around whether or not a user should be permitted to access a particular site.

Going online on behalf of others: An investigation of ‘proxy’ internet consumers

Abstract: A range of Australians find themselves acting as ‘proxy internet users’ – i.e. using online services and applications on behalf of other adults who otherwise make limited use of the internet. Researchers at Monash University and Federation University have looked at the way proxy use works, finding that despite proxy internet users commonly involving themselves in important and/or ‘risky’ online activities – e.g. banking, personal finances and purchasing goods, few have considered the possible implications of their help to both themselves, or the person they are assisting. The paper below highlights a number of issues that merit attention from communications stakeholders and provides a set of recommendations to help ensure proxy internet use can be a positive experience for all. Also check out the Proxy User Tip Sheet which runs consumers through some of the things to think about if you are using the internet on another's behalf.

Neighbor Awareness Networking Service Discovery Proxy

Abstract: In some embodiments, one or more wireless stations operate to configure Neighbor Awareness Networking (NAN)—direct communication with neighboring wireless stations without utilizing an intermediate access point. Embodiments of the disclosure relate to aspects of NAN communication, including service discovery proxy registration, publishing, and subscription of services via the proxy, maintenance of the proxy, and de-registration of the proxy.

A short ID-based proxy signature scheme

Abstract: The notion of identity-based proxy signature with message recovery feature has been proposed to shorten identity-based proxy signatures and improve their communication overhead because signed messages are not transmitted with these kinds of signatures. There are a few schemes for this notion: the schemes of Singh and Verma and Yoon et al. Unfortunately, Tian et al., by presenting two forgery attacks, show that Singh and Verma scheme is not secure, and also, the scheme of Yoon et al. does not support provable security. The contributions of this paper are twofold. First, we review the scheme by Yoon et al. and discuss why it does not have message recovery property, and consequently, it is not short. Second, we propose a short identity-based proxy signature scheme with the help of message recovery property and show that it is secure under computational Diffie-Hellman assumption in the random oracle model. Furthermore, our scheme is more efficient than as efficient as previous identity-based proxy signatures. Copyright © 2014 John Wiley & Sons, Ltd.

A restricted proxy re-encryption with keyword search for fine-grained data access control in cloud storage

Abstract: For fine-grained data access control in cloud computing, for the first time, we introduce a new concept called restricted proxy re-encryption with keyword search, which combines the function of proxy re-encryption with keyword search and that of threshold cryptosystem. To demonstrate this concept, we present the formal syntax for restricted proxy re-encryption with keyword search, the security model, and a concrete construction. In our scheme, we take advantage of the techniques of threshold cryptosystem to restrict the capacity of the proxy cloud server, and in the meantime, we let the proxy cloud server can only re-encrypt the data containing a specified keyword, which matches the trapdoor from delegatee to provide an accurate access control for users. While in this process, the proxy cloud server learns nothing about the contents of data and keyword. Our scheme is proved to be semantically secure under the modified bilinear Diffie-Hellman assumption and the q-decisional bilinear Diffie-Hellman inversion assumption in the random oracle model. Finally, we apply the techniques in our scheme to some practical problems. Copyright © 2016 John Wiley & Sons, Ltd.

Killed by Proxy: Analyzing Client-end TLS Interce.

Abstract: To filter SSL/TLS-protected traffic, some antivirus and parental-control applications interpose a TLS proxy in the middle of the host’s communications. We set out to analyze such proxies as there are known problems in other (more matured) TLS processing engines, such as browsers and common TLS libraries. Compared to regular proxies, client-end TLS proxies impose several unique constraints, and must be analyzed for additional attack vectors; e.g., proxies may trust their own root certificates for externally-delivered content and rely on a custom trusted CA store (bypassing OS/browser stores). Covering existing and new attack vectors, we design an integrated framework to analyze such client-end TLS proxies. Using the framework, we perform a thorough analysis of eight antivirus and four parentalcontrol applications for Windows that act as TLS proxies, along with two additional products that only import a root certificate. Our systematic analysis uncovered that several of these tools severely affect TLS security on their host machines. In particular, we found that four products are vulnerable to full server impersonation under an active man-in-the-middle (MITM) attack out-of-the-box, and two more if TLS filtering is enabled. Several of these tools also mislead browsers into believing that a TLS connection is more secure than it actually is, by e.g., artificially upgrading a server’s TLS version at the client. Our work is intended to highlight new risks introduced by TLS interception tools, which are possibly used by millions of users.

Social Media, Internet, and Corruption

Abstract: In this paper we study the relationship between multi-way means of communication and corruption. Unlike traditional platforms like TV or print media, which only provide a one-way channel of communication, the internet and social media platforms provide for two-way flow of information. Using Facebook as a proxy for social media, we show that Facebook penetration and corruption are negatively associated. The same holds for internet penetration. We then exploit variations in cross-country technological adoption in the field of communication in 1500 AD to address endogeneity concerns. We show that internet penetration and Facebook penetration have a causal and negative impact on corruption. Our results also suggest that these effects are sizable making them effective tools against corruption.

Macroeconomic Expectations and the Size, Value, and Momentum Factors

Abstract: When examining the sources of risk associated with priced factors, the prior literature often uses macroeconomic realizations to proxy for changes in expectations. However, realizations can be biased, so instead we use changes in macroeconomic forecasts and macroeconomic news surprises. The sensitivity of common factors to macroeconomic risks is not robust, and generally economically and statistically insignificant. Sometimes the factors even hedge risk. Importantly, the weak relation between the factors and risks is not the result of low powered tests. These findings are inconsistent with the notion that the factors are priced because they proxy for the macroeconomic risks examined.