Showing papers on "Proxy (statistics) published in 1997"

Proxy signatures, Revisited

Abstract: Proxy signatures, introduced by Mambo, Usuda and Okamoto allow a designated person to sign on behalf of an original signer. This paper first presents two new types of digital proxy signatures called partial delegation with warrant and threshold delegation. Proxy signatures for partial delegation with warrant combines the benefit of Mambo's partial delegation and Neuman's delegation by warrant, and then in threshold delegation the proxy signer's power to sign messages is shared. Moreover, we also propose straightforward and concrete proxy signature schemes satisfying our conditions.

Proxy host computer and method for accessing and retrieving information between a browser and a proxy

Abstract: A query (160) is sent from a browser (100, 101) to a proxy (300) directed to an information source (140) in a networked data communications system. In one aspect, the query is modified by the proxy to provide a modified query and the modified query is forwarded to the information source (120). A response (170) is received at the proxy from the information source and forwarded to the browser. In another aspect the response is modified by the proxy to provide a modified response (370) which is forwarded to the browser. The proxy (300) has a file (341) of services established for at least one specified browser (100) and filter (302, 304) for filtering queries and responses from browsers. The filters are responsive to the file of services for filtering queries from the at least one specified browser.

Threshold Proxy Signature Schemes

Abstract: Delegation of rights is a common practice in the real world. Proxy signature schemes have been invented to delegate signing capability efficiently and transparently. In this paper, we present a new nonrepudiable proxy signature scheme. Nonrepudiation means the signature signers, both original and proxy signers, cannot falsely deny later that he generated a signature. In practice, it is important and, sometimes, necessary to have the ability to know who is the actual signer of a proxy signature for internal auditing purpose or when there is abuse of signing capability. The new nonrepudiable proxy signature scheme also has other desirable properties, such as proxy signature key generation and updating using insecure channels. We also show how to construct threshold proxy signature schemes with an example. Threshold signatures are motivated both by the need that arises in some organizations to have a group of employees agree on a given message (or a document) before signing it, as well as by the need to protect signature keys from the attack of internal and external adversaries. Our approach can also be applied to other ElGamal-like proxy signature schemes.

Assessing Quality of Life After Stroke The Value and Limitations of Proxy Ratings

Abstract: Background and Purpose Because many stroke survivors have cognitive and communication disorders, self-reported information on a patient’s quality of life (QL) cannot always be obtained. Proxy ratings may be used to prevent exclusion of this highly relevant subgroup of patients from QL studies. The purpose of this study was to evaluate both the value and possible limitations of such proxy ratings. Methods The patient sample was composed of 437 patients who had suffered a stroke 6 months earlier. QL was assessed by means of the Sickness Impact Profile (SIP). For 108 patients who were not communicative because of cognitive or linguistic deficits, proxy ratings on the SIP were provided by the patients’ significant others. For 228 of the 329 communicative patients, both self-reported and proxy SIP ratings were obtained. Results When mean SIP scores for patients with both self-reported and proxy-derived data available were compared, the proxy mean scores were generally in close agreement with those of the patie...

The use of significant others as proxy raters of the quality of life of patients with brain cancer.

Abstract: Objectives.The use of self-report questionnaires for the assessment of health-related quality of life (HRQOL) is increasingly common in clinical research. This method of data collection may be less suitable for patient groups who suffer from cognitive impairment, however, such as patients with brain

Ownership studies: The data source does matter

Abstract: We examine the fit between the ownership data provided by four surrogate databases and the data collected from proxy statements. We discover an unambiguous pecking order among the surrogates relative to the benchmark ownership statistics of corporate proxy statements. Corporate Text is first, followed in descending order by Compact Disclosure, Value Line, and Spectrum. Further tests show that reporting discrepancies in the Value Line and Spectrum databases could affect economic inferences drawn from regressions using their ownership data. A field guide describing each data source's reporting conventions, formats, and strate? gies for data aggregation may be downloaded from the Journal of Financial and Quantitative Analysis' web site (http.V/weber.u.washington.edu/~jfqa/hola7andeapdx.pdf).

Method and apparatus for detecting a user-controlled parameter from a client device behind a proxy

Abstract: A method for obtaining a user-controlled parameter from a client device arranged behind a network proxy includes the steps of receiving a request originated by the client device; transmitting a responsive request to the client device, where the responsive request includes a query mechanism to elicit a user-controlled parameter from the client device; and receiving the user-controlled parameter from the client device.

A general purpose proxy filtering mechanism applied to the mobile environment

Abstract: Host mobility complicates the standard networking model in unexpected ways. It increases network heterogeneity, causing difficulty within applications that expect a high or constant amount of network bandwidth. Mobility increases cost when a user switches from a relatively inexpensive high bandwidth network to a low bandwidth pay‐by‐call or pay‐by‐byte network. Mobility may also reduce security when a user moves from a “safe” network onto a foreign one. This situation can be improved by introducing a proxy between the mobile client and its peer. The purpose of this intermediary is to process data moving between the client and peer. The type of processing performed depends on the desired result: the proxy can hide network heterogeneity via data filtering, reduce cost by using compression, and increase security through the use of secure protocols between the client and proxy. This paper presents a general purpose proxy system and how it has been applied to the mobile environment. The overall architecture is described, examples of its use given, and a study on its feasibility and performance is presented.

Network proxy capable of dynamically selecting a destination device for servicing a client request

Abstract: A dynamically-chainable network proxy is implemented in a method for chaining a network proxy to a destination device, wherein the network proxy is coupled to a source device and a plurality of destination devices, including the step of receiving a request from the source device at the network proxy. The network proxy then selects one of the plurality of destination devices to serve the request, with the selection made according to a predetermined selection criterion. The network proxy reformats the request to designate the selected destination device, and then forwards the reformatted request to the selected destination device.

The Proxy Model of Social Comparison for Self-Assessment of Ability

Abstract: One purpose of the social comparison of abilities is to determine action possibilities-"Can I do X?" By comparing ourselves with a proxy who has attempted X, we can determine our likelihood of success. A good proxy is one who has performed the same as us on an initial task requiring the ability. In addition, however, a good proxy must be similar on related attributes so that we can be confident that the proxy's performance on the initial task was maximal. In the case of a task requiring multiple abilities, more than one proxy may be used.

Trends in the Training of Male and Female Workers in the United Kingdom

Abstract: After controlling for the effect of impact of human capital and other characteristics, including whether respondents are interviewed directly or by proxy, there has been a convergence in the experience of women and men regarding access to training in Britain. This convergence applies both to total training participation in any four weeks and to the weekly volume of off-the-job training.

Method for transferring and displaying data pages on a data network

Abstract: The apparent speed of a connection between a browser at a user station and a proxy or gateway on a network such as the Internet is increased by providing a local proxy at the user station which interacts with a remote proxy. While the remote proxy is retrieving a newly requested World Wide Web page, for example, from the appropriate content provider, it may also be sending to the local proxy a stale cached version of that page. When the new version of the page is finally retrieved, the remote proxy determines the differences between the new version and the stale version, and, assuming the differences do not exceed the new page in size, sends the differences to the local proxy which then reconstructs the new page from the differences and the stale version. The local proxy delivers the new page to the browser, which need not even be aware that a local proxy exists; it is aware only that it received the page it requested. Because computational speed and power are frequently higher and cheaper than transmission speed, the apparent speed of the connection between the user station and the network has been increased at modest cost.

Intelligent proxy objects

Abstract: A method, apparatus, and article of manufacture for editing an object created by an object-controlling application program when the object-controlling application program is not available. First, an indication that the object is to be manipulated is received. Then, it is determined that the object-controlling application program is not available to manipulate the object. An intelligent proxy object is created as a placeholder for the object when it is determined that the object-controlling application program is not available. Manipulation operations are performed on the created intelligent proxy object. Further, data relating to the performed manipulation operations is stored.

General purpose proxies: solved and unsolved problems

Abstract: Proxies are becoming increasingly common. One use of a proxy is to address network heterogeneity, which can arise especially in mobile computing. In this setting, a proxy can process the traffic flowing to and from a network limited mobile host, damping the variations in application performance as well as providing other benefits such as reduced cost and increased security. We describe the issues we faced in designing such a proxy system, how we solved some problems, and why others could not be solved.

Of Genes and IQ

Abstract: The fundamental premise of Herrnstein and Murray’s opus, The Bell Curve, is that intelligence and its proxy IQ are determined primarily by genes.1 Economic and social success, according to their analyses, are determined primarily by IQ. Thus logic dictates that economic and social success are due largely to genes, which therefore explains why government interventions to improve the lot of the poor have been on the whole unsuccessful. In one eloquent volume, the authors serve up justification for that oft-heard refrain “the poor will always be poor.”

Technique for effectively managing proxy servers in intranets

Abstract: In a communication arrangement including a multiplicity of intranets, objects available on the Internet are requested. A requested object in an intranet is attended by a proxy server therein, which attempts to locate a copy of the requested object in a proxy cache. The latter stores copies of objects previously obtained by web browsers in the intranet, and affords priority to copies of those objects from selected Internet sites. If the proxy server does not manage to locate a copy of the requested object or determines that a located copy is outdated, the proxy server seeks cooperation from other proxy servers to further search for the object. These cooperating proxy servers are dynamically identified by a manager processor in accordance with the invention. In addition, the manager processor prefetches selected objects from the Internet in anticipation of the object request. The manager processor also helps search the prefetched objects for the requested object.

Evaluating non-structural measures of the business cycle

Abstract: This paper evaluates a number of non-structural measures of the business cycle. It adopts a structural definition of the cycle, interprets non-structural measures as noisy approximations, and seeks a proxy that is reliable across a variety of plausible trend-cycle structures. The results favor a consumption-based measure proposed by Cochrane (1994). Across a variety of structures, it has the highest correlation and coherence with structural cycles, and best matches their dynamic properties. When applied to U.S. data, consumption-based measures conform closely to the dates of NBER recessions. They also yield a strong negative correlation between the cyclical components of productivity and hours, a fact that deepens the challenge to models which emphasize technology shocks as the primary source of business cycles.

Social comparison and task prediction: ability similarity and the use of a proxy.

Abstract: It is argued that an important aspect of the self-appraisal of ability involves a person's prediction of his or her own performance level on untried tasks through acquisition of knowledge about how other people have fared at the task. These others are treated as substitutes for a person's own participation in the task--as proxies. It is further argued that social comparison plays a significant role in both the selection of proxies and the impact of proxy information on task prediction. The first experiment, following earlier research on comparison preference in the context of performance prediction, showed that participants interested in performance prediction chose a proxy who had performed at about the same level as they had on a reference task, while those interested in improving their performances chose to see the performances of someone who had done far better than they on the reference task. The second study indicated that participants made more confident predictions for themselves from a similar proxy's task outcome than from that of a proxy whose ability was unknown to them. Participants predicted they would do worse than a more able proxy and better than a less able proxy, but were less confident in their predictions than were those with a similar proxy. Ratings of usefulness of the proxy followed the patterns of confidence ratings closely.

Method and apparatus for pre-fetching data for an application using a winsock client layered service provider and a transparent proxy

Abstract: Response time is improved by a method and apparatus for pre-fetching application data over a network. A request for application data, such as Internet data, is received. The request is transmitted to a transparent network proxy, which issues requests over a communications network to fetch the requested data. The requested application data are received by the proxy and forwarded to a client layered service provider, which supplies the data to the application. If additional application data is received by the proxy, that data is also forwarded to the client layered service provider, where it is stored as pre-fetch data. If additional application data is requested by the application, the additional data can be supplied from the stored pre-fetch data, if available.

Risk Factors for Adolescent Violence: The Importance of Vulnerability

Abstract: Violence as a function of vulnerability and delinquency was examined in a sample of 2066 ninth-graders. Vulnerability was examined by several proxy measures (being hit, attacked, or touched inappro...

Measuring the Impact of Direct and Indirect R&D on the Productivity Growth of Industries: Using the Yale Technology Concordance

Abstract: This paper investigates the impact of direct and indirect R&D on the productivity growth of 30 French industries during the period 1978–92. The main aim of this paper is to assess the appropriateness of the Yale Technology Concordance (YTC) as a proxy for indirect R&D flows. We compare the effect on productivity growth of the Yale proxy with the traditional proxy based on goods input–output flows, and assess their suitability for different groups of industries. Results indicate that the indirect YTC proxy performs slightly better than the traditional proxy, as a result of superior performance in the high-tech and service sectors in particular.

Communication Costs, Information Acquisition, and Voting Decisions in Proxy Contests

Abstract: This article synthesizes some recent progress in the theories of corporate control and political lobbying to model the proxy campaign as a political campaign. The model yields a number of testable implications, only some of which have been examined in the literature. For example, if the loss from voting for a "bad" dissident exceeds the gain from voting for a "good" dissident, the model predicts that as communication costs fall, the number of proxy fights increases, announcement day returns decrease, and the fraction of dissident wins first increases and then decreases. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.

Further Estimates of the Economic Return to Schooling from a New Sample of Twins

Abstract: In a recent and widely cited paper, Ashenfelter and Krueger (1994) use a new sample of identical twins to test whether schooling represents an investment in human capital or is merely a proxy for genetic ability I re-examine Ashenfelter and Krueger's estimates using three additional years of the twins survey I estimate that the return to schooling among identical twins is about 10-12 percent per year of schooling completed Most importantly, unlike the results reported in Ashenfelter and Krueger, I find that the within-twin regression estimate of the return to schooling is smaller than the cross-sectional estimate, implying a small upward bias in the cross-sectional estimate

A Spatial Model of Housing Returns and Neighborhood Substitutability

Abstract: This paper provides a method for estimating housing indicesat the local level. It develops a "distance-weightedrepeat-sale" procedure to exploit the factor structure ofthe error-covariance matrix in the repeat-sales model. Adistance function defined in characteristic andgeographical space provides weights for the generalizedleast-squares model, and allows the use all of the repeated-sales in a metropolitan area to measure returns for thespecific neighborhood of interest. We use distance-weightedrepeat-sales to estimate return indices for all zip codes inthe San Francisco Bay area over the period 1980 through1994. When distance is defined in terms of socio-economiccharacteristics, we find that median household income is thesalient variable explaining covariance of neighborhoodhousing returns. Racial composition and educationalattainment, while significant, are much less influential.Zip-code level indices often deviate dramatically from thecity-wide index, depending upon income levels. This hasimplications for investors and lenders. Our resultsindicate that rates of return may vary considerably within ametropolitan area. Thus, simply using broad metropolitanarea indices as a proxy for capital appreciation within aspecific neighborhood may not be justified.

Are ex-post real interest rates a good proxy for ex-ante real rates?: an international comparison within a CCAPM framework

Abstract: We use an integrated framework based on the CCAPM to jointly estimate ex-ante real interest rates, (bounds on) inflation risk premia and (bounds on) agents' inflation expectation errors in four countries -France, Spain, UK and USunder three different preference specifications. According to our results, I-year ex-ante real interest rates exhibit a rather low correlation with the I-year ex-post rate. For those ex-ante real rates showing the highest correlation with the ex-post real rate, the difference between both real rates seems to be mainly explained in terms of agents' inflation expectation errors, while the inflation premia play a minor role.

The Central Tendency: A Second Factor in Bond Yields

Abstract: We assume that the instantaneous riskless rate reverts towards a central tendency which in turn, is changing stochastically over time As a result, current short-term rates are not" sufficient to predict future short-term rates movements, as would be the case if the central" tendency was constant However, since longer-maturity bond prices incorporate information" about the central tendency, longer-maturity bond yields can be used to predict future short-term" rate movements We develop a two-factor model of the term-structure which implies that a" linear combination of any two rates can be used as a proxy for the central tendency Based on" this central-tendency proxy, we estimate a model of the one-month rate which performs better" than models which assume the central tendency to be constant

Ownership Studies: The Data Source Does Matter

Abstract: We examine the fit between the ownership data provided by four surrogate databases and the data collected from proxy statements. We discover an unambiguous pecking order among the surrogates relative to the benchmark ownership statistics of corporate proxy statements. Corporate Text is first, followed in descending order by Compact Disclosure, Value Line, and Spectrum. Further tests show that reporting discrepancies in the Value Line and Spectrum databases could affect economic inferences drawn from regressions using their ownership data. A field guide describing each data source's reporting conventions, formats, and strategies for data aggregation may be downloaded from the Journal of Financial and Quantitative Analysis' web site.