Showing papers on "Proxy (statistics) published in 2010"

Efficient unidirectional proxy re-encryption

Abstract: Proxy re-encryption (PRE) allows a semi-trusted proxy to convert a ciphertext originally intended for Alice into one encrypting the same plaintext for Bob. The proxy only needs a re-encryption key given by Alice, and cannot learn anything about the plaintext encrypted. This adds flexibility in various applications, such as confidential email, digital right management and distributed storage. In this paper, we study unidirectional PRE, which the re-encryption key only enables delegation in one direction but not the opposite. In PKC 2009, Shao and Cao proposed a unidirectional PRE assuming the random oracle. However, we show that it is vulnerable to chosen-ciphertext attack (CCA). We then propose an efficient unidirectional PRE scheme (without resorting to pairings). We gain high efficiency and CCA-security using the “token-controlled encryption” technique, under the computational Diffie-Hellman assumption, in the random oracle model and a relaxed but reasonable definition.

The Information Content of IPO Prospectuses

Abstract: Using word content analysis, we decompose information in the initial public offering prospectus into its standard and informative components. Greater informative content, as a proxy for premarket due diligence, results in more accurate offer prices and less underpricing, because it decreases the issuing firm's reliance on bookbuilding to price the issue. The opposite is true for standard content. Greater content from high reputation underwriters and issuing firm managers, through Management's Discussion and Analysis, contribute to the informativeness of the prospectus. Our results suggest that premarket due diligence and disclosure by underwriters and issuers can serve as a substitute for costly bookbuilding. The Author 2010. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org., Oxford University Press.

Google Search Volume and its Influence on Liquidity and Returns of German Stocks

Abstract: We show that the search volume on Google not only serves as an intuitive proxy for overall recognition in a firm, but also captures the attention of stock market investors. Our results suggest that an increase in search queries is associated with a rise in trading activity and stock liquidity. We attribute the improved liquidity to a reduction in asymmetric information costs and conclude that the search volume primarily measures the recognition of uninformed investors. Moreover we find evidence that an increase in search volume is associated with temporarily higher future returns, which reinforces our previous finding.

Application-proxy support over a wireless link

Abstract: Application proxy support over a wireless link between a mobile device and a wireless node is disclosed. Application proxy support is configured to conserve energy and resources and is configured to mitigate delays in a communication environment. Application proxy support can be associated with a wireless node, such as a femto cell, which can provide a coarse-grain wireless application proxy support that can utilize various criteria to buffer data and determine how long to delay delivery of data. Femto cell can provide a fine-grain wireless application proxy that runs application proxies for each mobile device for one or more applications associated with mobile device. The proxy can determine whether to buffer and forward received data to mobile device. The wireless application proxy can respond to network on behalf of mobile device. The proxy can wake up mobile device upon arrival of a significant event associated with a proxied application.

Using proxy measures and other correlates of survey outcomes to adjust for non-response: examples from multiple surveys

Abstract: Summary. Non-response weighting is a commonly used method to adjust for bias due to unit non-response in surveys. Theory and simulations show that, to reduce bias effectively without increasing variance, a covariate that is used for non-response weighting adjustment needs to be highly associated with both the response indicator and the survey outcome variable. In practice, these requirements pose a challenge that is often overlooked, because those covariates are often not observed or may not exist. Surveys have recently begun to collect supplementary data, such as interviewer observations and other proxy measures of key survey outcome variables. To the extent that these auxiliary variables are highly correlated with the actual outcomes, these variables are promising candidates for non-response adjustment. In the present study, we examine traditional covariates and new auxiliary variables for the National Survey of Family Growth, the Medical Expenditure Panel Survey, the American National Election Survey, the European Social Surveys and the University of Michigan Transportation Research Institute survey. We provide empirical estimates of the association between proxy measures and response to the survey request as well as the actual survey outcome variables. We also compare unweighted and weighted estimates under various non-response models. Our results from multiple surveys with multiple recruitment protocols from multiple organizations on multiple topics show the difficulty of finding suitable covariates for non-response adjustment and the need to improve the quality of auxiliary data.

Methods and apparatuses for providing internet-based proxy services

Abstract: A proxy server receives, from multiple visitors of multiple client devices, a plurality of requests for actions to be performed on identified network resources belonging to a plurality of origin servers. At least some of the origin servers belong to different domains and are owned by different entities. The proxy server and the origin servers are also owned by different entities. The proxy server analyzes each request it receives to determine whether that request poses a threat and whether the visitor belonging to the request poses a threat. The proxy server blocks those requests from visitors that pose a threat or in which the request itself poses a threat. The proxy server transmits the requests that are not a threat and is from a visitor that is not a threat to the appropriate origin server.

Method and system for secure and reliable video streaming with rate adaptation

Abstract: A system for media delivery includes a server-side proxy for aggregating and encrypting stream data for efficient HTTP-based distribution over an unsecured network. A client-side proxy decrypts and distributes the encapsulated stream data to client devices. A multicast-based infrastructure may be used for increased scalability. The encoded rate of the media delivered over the persistent HTTP proxy connections may be dynamically adapted. The client-side proxy may be integrated within a mobile device for maximum network security and reliability.

The Market Portfolio May Be Mean/Variance Efficient After All

Abstract: Numerous studies have examined the mean/variance efficiency of various market proxies by employing sample parameters and have concluded that these proxies are inefficient. These findings cast doubt about the capital asset pricing model (CAPM), one of the cornerstones of modern finance. This study adopts a reverse-engineering approach: given a particular market proxy, we find the minimal variations in sample parameters required to ensure that the proxy is mean/variance efficient. Surprisingly, slight variations in parameters, well within estimation error bounds, suffice to make the proxy efficient. Thus, many conventional market proxies could be perfectly consistent with the CAPM and useful for estimating expected returns. The Author 2010. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org., Oxford University Press.

Payment Channel Returning Limited Use Proxy Dynamic Value

Abstract: A central platform provides proxy dynamic values for any one of a number of a cardholder's portable payment devices, upon a request for such information made during a transaction. The proxy dynamic value can be provided to the merchant, who then can route it into the acceptance network in order to initiate the authentication process. The central platform provides the actual primary account number associated with the proxy dynamic value during the authentication process.

The Power of Proxy Advisors: Myth or Reality?

Abstract: Recent regulatory changes increasing shareholder voting authority have focused attention on the role of proxy advisors. In particular, greater shareholder empowerment raises the question of how much proxy advisors influence voting outcomes. This Article analyzes the significance of voting recommendations issued by four proxy advisory firms in connection with uncontested director elections. We find, consistent with press reports, that Institutional Shareholder Services (ISS) is the most powerful proxy advisor and that, of the others, only Glass, Lewis & Co. seems to have a meaningful impact on shareholder voting.This Article also attempts to measure the impact of voting recommendations on voting outcomes. Unlike prior literature, it distinguishes correlation from causality by examining both the recommendation itself and the underlying factors that may influence a shareholder’s vote. Using several different tests, we conclude that popular accounts substantially overstate the influence of ISS. Our findings reveal that the impact of an ISS recommendation is reduced greatly once company- and firm-specific factors important to investors are taken into consideration. Overall, we estimate that an ISS recommendation shifts 6%–10% of shareholder votes. We also determine that a major component of ISS’s influence stems from its role as an information agent, aggregating factors that its subscribers consider important.

CCA-secure unidirectional proxy re-encryption in the adaptive corruption model without random oracles

Abstract: Up to now, it is still an open question of how to construct a chosen-ciphertext secure unidirectional proxy re-encryption scheme in the adaptive corruption model. To address this problem, we propose a new unidirectional proxy re-encryption scheme, and prove its chosen-ciphertext security in the adaptive corruption model without random oracles. Compared with the best known unidirectional proxy re-encryption scheme proposed by Libert and Vergnaud in PKC’08, our scheme enjoys the advantages of both higher efficiency and stronger security.

Proxy Apparatus and Method for Streaming Media Information and for Increasing the Quality of Stored Media Information

Abstract: A proxy apparatus and method for streaming media information via at least one network and for building-up a good quality version of the media information. When a user device communicates with the proxy apparatus using a particular bandwidth and requests that media information be provided from a media server, the proxy apparatus first determines if a version of the media information encoded for the user device's connection bandwidth has been stored in the proxy apparatus. If a version of the media information encoded for the user device's bandwidth is not available from the proxy apparatus, the proxy apparatus sends a request to a media server for the media information. Once the media server receives the request, the media server begins to stream a copy of the media information encoded for the user device's bandwidth to the user device via the network and proxy device. If a version of the media information for the bandwidth is not available from the media server, the version for the largest bandwidth that does not exceed the bandwidth of the user device connection, is streamed to the user device. If the version of the media information has missing packets, the proxy device sends retransmission requests to the media server to obtain the missing packets, thereby building-up a good quality version of the media information.

Interim News and the Role of Proxy Voting Advice

Abstract: This article examines the information content and consequences of third-party voting advice that arrives as news at an interim stage in corporate proxy contests. We first document significant stock returns around announcements of proxy vote recommendations. We then develop a multi-equation empirical procedure for disentangling the price impact of prediction effects (changes in contest outcome probabilities) from the price impact of certification effects (changes in outcome-contingent valuations). Both effects are present in the data: Voting advice is both predictive about contest outcomes and informative about the ability of dissidents to add value. Consequently, proxy advice plays a dual informational role. , Oxford University Press.

An Empirical Analysis of the Impact of the Nigerian Capital Market on Her Socio-economic Development

Abstract: The objective of this study was to empirically analyze the impact of the Nigerian capital market on her socio-economic development from 1981 to 2008. The socio-economic development was proxy by the...

Do labor statistics depend on how and to whom the questions are asked? : results from a survey experiment in Tanzania

Abstract: Labor market statistics are critical for assessing and understanding economic development. However, widespread variation exists in how labor statistics are collected in household surveys. This paper analyzes the effects of alternative survey design on employment statistics by implementing a randomized survey experiment in Tanzania. Two features of the survey design are assessed - the level of detail of the employment questions and the type of respondent. It turns out that both features have relevant and statistically significant effects on employment statistics. Using a short labor module without screening questions induces many individuals to adopt a broad definition of employment, incorrectly including domestic duties. But after reclassifying those in domestic work as 'not working' in order to obtain the correct International Labor Organization (ILO) classification, the short module turns out to generate lower female employment rates, higher working hours for both men and women who are employed, and lower rates of wage employment than the detailed module. Response by proxy rather than self-report has no effect on female labor statistics but yields substantially lower male employment rates, mostly due to underreporting of agricultural activity. The large impacts of proxy responses on male employment rates are attenuated when proxy informants are spouses and individuals with some schooling.

Power savings through cooperative operation of multiradio devices

Abstract: Proxy discovery for mobile networks having cooperative multiradio devices is provided through short range discovery and assistance from the network. In some aspects, a dedicated message is sent in response to a request from the client. The dedicated message includes a proxy list. The client uses the proxy list to discover those proxies on the list. Other aspects provide for the proxy list to be included in broadcast messages from the network. Thus, clients receive the broadcast messages and extract the proxy list for discovery purposes. Other aspects provide for the client to detect all of the wireless devices in the area and send a list to the network. The network responds with a sub-list of those proxies that are available to the client. In each such aspect, when the client discovers the available proxies, it transmits a list of the proxy ID of the discovered proxies to the network.

Social Learning, Social Influence, and Projection Bias: A Caution on Inferences Based on Proxy Reporting of Peer Behavior

Abstract: This study explores the consequences of conflating social learning and social influence concepts and of the widespread use of proxy‐reported behavioral data for accurate understanding of learning from others. Our empirical analysis suggests that proxy reporting is more accurate for new innovations, about which social learning is more plausible, than for mature technologies. Furthermore, proxy‐reporting errors are correlated with respondent attributes, suggesting projection bias. Self‐ and proxy‐reported variables generate different regression results, raising questions about inferences based on error‐prone, proxy‐reported peer behaviors. Self‐reported peer behavior consistently exhibits statistically insignificant effects on network members’ adoption behavior, suggesting an absence of social effects.

Location Efficiency and Mortgage Default

Abstract: Using a sample of over 40,000 mortgages in Chicago, Jacksonville, and San Francisco, we model the probability of mortgage default based on differences in location efficiency. We used two proxy vari...

New identity-based proxy re-encryption schemes to prevent collusion attacks

Abstract: In this paper, we propose two new constructions of identity-based proxy re-encryption (IB-PRE). The most important feature of our schemes is that we no longer need the semi-trust assumption on the proxy. Moreover, we describe the IND-PrID-CCA/CPA security models for an IB-PRE in a single-hop scenario, and then give a general analysis on the relationship between the IND-PrID-CPA security model and the desirable PRE properties: unidirectionality, collusion "safeness" and nontransitivity. Our first scheme has no ciphertext expansion through the re-encryption and is proven IND-PrID-CPA secure in the random oracle model. The second one achieves the IND-PrID-CCA security.

Proxy Re-encryption with Keyword Search: New Definitions and Algorithms

Abstract: We propose a new definition for searchable proxy re-encryption scheme (Re-PEKS), define the first known searchable proxy re-encryption scheme with a designated tester (Re-dPEKS), and then give concrete constructions of both Re-PEKS and Re-dPEKS schemes that are secure in the random oracle model.

An advanced secure (t, n) threshold proxy signature scheme based on RSA cryptosystem for known signers

Abstract: In a (t,n) threshold proxy signature scheme based on RSA, any t or more proxy signers can cooperatively generate a proxy signature while t-1 or fewer of them can't do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers [8]. In this article, we discuss the implementation and comparison of some threshold proxy signature schemes that are based on the RSA cryptosystem. Comparison is done on the basis of time complexity, space complexity and communication overhead. We compare the performance of four schemes: Hwang et al. [1], Wen et al.[2], Geng et al.[3] and Fengying et al[4] with the performance of a scheme that has been proposed by the authors of this article earlier and proposed an advanced secure (t, n) threshold proxy signature scheme. In the proposed scheme, both the combiner and the secret share holder can verify the correctness of the information that they are receiving from each other. Therefore, the proposed scheme is secure and efficient against notorious conspiracy attacks.

Apparatus and method for accelerating streams through use of transparent proxy architecture

Abstract: A communication apparatus for remote communication may include a local transparent proxy module configured to intercept a first stream destined to a remote destination and configured to make a first determination whether to accelerate communication associated with the first stream. The communication apparatus may include a local proxy module configured to receive the first stream based on the first determination and configured to make a second determination whether a connection to a remote proxy module is established. If the connection is established, then the local proxy module may receive one or more additional streams and may direct the one or more additional streams to the remote proxy module utilizing an accelerated mode. If the connection is not established, then the local transparent proxy module may direct the first stream to the remote destination utilizing a non-accelerated mode. A machine-readable medium and a method are also disclosed.

The Value of Luminosity Data as a Proxy for Economic Statistics

Abstract: One of the pervasive issues in social and environmental research has been to improve the quality of socioeconomic data in developing countries. Because of the shortcoming of standard data sources, the present study examines luminosity (measures of nighttime lights) as a proxy for standard measures of output. The paper compares output and luminosity at the country levels and at the 1° x 1° grid-cell levels for the period 1992-2008. The results are that luminosity has very little value added for countries with high-quality statistical systems. However, it may be useful for countries with the lowest statistical grades, particularly for war-torn countries with no recent population or economic censuses. The results also indicate that luminosity has more value added for economic density estimates than for time-series growth rates.

Provision of an environmental output within a multi-output distance function approach

Abstract: This paper redefines technical efficiency by incorporating provision of environmental goods as one of the outputs of the farm within a multi-outptut distance function framework. Permanent and rough grassland area are used as a proxy for the provision of environmental goods. The multi-output distance function approach is used to estimate technical efficiency. A Bayesian procedure involving the use of a Gibbs sampler is used to estimate the farm specific efficiency as well as the coefficients of the distance function. In addition, a number of explanatory variables for the efficiency were introduced in the analysis and posterior distributions of those were obtained. The methodology is applied to panel data on 215 dairy farms in England and Wales from the Defra Farm Business Survey. Results show that both farm efficiency rankings and determinants of inefficiency change when provision of environmental outputs by farms is incorporated in the efficiency analysis, which may have important political implications.