Showing papers on "Proxy (statistics) published in 1996"

Proxy signatures for delegating signing operation

Abstract: In this paper a new type of digital proxy signature is proposed. The proxy signature allows a designated person, called a proxy signer, to sign on behalf of an original signer. Classification of the proxy signatures is shown from the point of view of the degree of delegation, and conditions of a proposed proxy signature for partial delegation are clarified. The proposed proxy signature scheme is based on the discrete logarithm problem. Compared to the consecutive execution of the ordinary digital signature schemes, it has a direct form, and a verifier does not need a public key of a user other than the original signer in the verification stage. Moreover, it requires less amount of computational work than the consecutive execution of the signature schemes. Due to this efficiency together with the delegation property, an organization, e.g. a software company, can very efficiently create many signatures of its own by delegating its signing operations to multiple employees. Another attractive feature of the proposed schemes is their highapplicability to other ordinary signature schemes based on the discrete logarithm problem. For instance, designated confirmer proxy signatures can be constructed. Furthermore, using a proposed on-line proxy updating protocol, the original signer can revoke proxies of dishonest proxy signers.

The Effects of Cross‐Sectional Scale Differences on Regression Results in Empirical Accounting Research*

Abstract: . This study investigates coefficient bias and heteroscedasticity resulting from scale differences in accounting levels-based research designs analytically and using simulations based on accounting data. Findings indicate that including a scale proxy as an independent variable is more effective than deflation at mitigating coefficient bias, even if the proxy is 95 percent correlated with the true scale factor. In fact, deflation can worsen coefficient bias. Also, deflation often does not noticeably reduce heteroscedasticity and can decrease estimation efficiency. White (1980) standard errors are close to the true ones in regressions using undeflated variables. Replications of specifications in three recent accounting studies confirm the simulation findings. The findings suggest that when scale differences are of concern, accounting researchers should include a scale proxy as an independent variable and report inferences based on White standard errors.

On the Validity of Using Census Geocode Characteristics to Proxy Individual Socioeconomic Characteristics

Abstract: Investigators of social differentials in health outcomes commonly augment incomplete microdata by appending socioeconomic characteristics of residential areas (such as median income in a zip code) to proxy for individual characteristics. But little empirical attention has been paid to how well this aggregate information serves as a proxy for the individual characteristics of interest. We build on recent work addressing the biases inherent in proxies and consider two health-related examples within a statistical framework that illuminates the nature and sources of biases. Data from the Panel Study of Income Dynamics and the National Maternal and Infant Health Survey are linked to census data. We assess the validity of using the aggregate census information as a proxy for individual information when estimating main effects and when controlling for potential confounding between socioeconomic and sociodemographic factors in measures of general health status and infant mortality. We find a general, but...

Secure network proxy for connecting entities

Abstract: A proxy which is part of a firewall program controls exchanges of information between two application entities. The proxy interrogates attempts to establish a communication session by requesting entities with a server entity in lower layers in accordance with defined authentication procedures. The proxy interfaces with networking software to direct a communication stack to monitor connection requests to any address on specific ports. The requestor's address, and the server's address are checked against an access control list. If either address is invalid, the proxy closes the connection. If both are valid, a new connection is setup such that both the requestor and server are transparently connected to the proxy with variable higher levels being connected in a relay mode. Protocol data units are interrogated for conformance to a protocol session, and optionally further decoded to add additional application specific filtering. In one embodiment, an OSI architecture comprises the levels.

Method for reducing the delay between the time a data page is requested and the time the data page is displayed

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.

Proxy-based reservation of network resources

Abstract: A method of communicating messages across a network is provided A router receives an RSVP (Resource Reservation Protocol) PATH message from a sending host that is directed to a receiving host Upon identifying the protocol of the incoming PATH message as RSVP, the router accesses a proxy look-up table to identify a proxy host acting on behalf of the receiving host The router then adds a proxy header to the PATH message and redirects the PATH message to the proxy host by sending the message to a predetermined port The proxy host receives the PATH message and, in response, sends a resource reservation request (RESV) message onto the network with a proxy header and directed to the predetermined port The router receives the RESV message, strips off the proxy header, and forwards the RESV message to the sending host as if the message had originated from the receiving host A proxy host can also send PATH messages on behalf of the sending host In that case, the proxy host adds a proxy header to the PATH message and directs the PATH message to the predetermined port The router receives the PATH message, strips off the proxy header, and sends the PATH message to the receiving host as if the PATH message had originated form the sending host The router also receives RESV messages from the receiving host or its proxy and redirects them to the proxy for the sending host

Telephone and in-person proxy agreement between stroke patients and caregivers for the functional independence measure.

Abstract: This study examined patient/proxy agreement for telephone administration of the Functional Independence Measure (FIM) to a sample of 25 community-living stroke patients 18 mo post-stroke and their caregivers. Patients had all received in-patient rehabilitation for stroke. Because use of the FIM is increasing for follow-up purposes, it is important to document whether it is appropriate to administer a telephone version to proxy caregivers in situations in which patients cannot answer for themselves. Proxy agreement results were then compared with those obtained for in-person administration of the FIM to the same sample 1 yr earlier. Overall, proxy agreement for telephone administration was excellent for total scores (intraclass correlation was 0.91) and the physical dimension (0.94) and lower for the cognitive dimension (0.52), closely paralleling results obtained for the earlier in-person administration. Reasons for lower agreement on the cognitive dimension are discussed.

Recoverable proxy object in an object oriented environment

Abstract: A mechanism is described for protecting a server against invalid usage of proxy objects (449) after malfunction of a server and also for transparently re-creating proxy objects in a client of a client-server distributed processing system. A proxy class is used that has additional attributes indicating the name (455) of the target object in the server, an indication as to whether the name is presently valid (459) and an alternate pointer (457) to the target object. A proxy register object (155) in the client maintains pointers to all the proxy objects (449) which point to objects in the server. On malfunction of the server, and consequent invalidity of the proxy objects (449), the proxy register object (155) causes all proxy objects (449) to be refreshed.

The Central Tendency: A Second Factor in Bond Yields

Abstract: In one-factor models, such as Cox, Ingersoll, and Ross (1985) or Vasicek (1977), the conditional mean of the instantaneous rate changes with its current level. This paper gathers evidence that the conditional mean of the one- month rate explains variations in bond yields of different maturities, even after controlling for the effect of the current level of the one-month rate. This suggests the presence of a second factor driving the conditional mean, other than the level of the one-month rate: we refer to this second factor as the central tendency. The above idea is captured in a two-factor model of the term structure where the instantaneous rate fluctuates around a stochastic central tendency. We then build a proxy for the central- tendency factor based on the information contained in the term structure of interest rates. We use the proxy to estimate the process for the one-month rate, and find the central-tendency proxy to be significant in explaining the conditional mean of the one-month rate.

Proxy-sharing proxy servers

Abstract: A proxy server is a Web server that caches Internet resources for re-use by a set of client machines. CERN's Web server implements proxy services and CERN-based proxy servers are in wide use at the enterprise level. This paper presents the design and implications of an extended proxy server that shares cache resources with near neighbors. A substantial reduction in internetwork load can be obtained from proxy sharing, with a corresponding increase in performance. Good performance comes from a simple implementation model that is non-hierarchical; proxies access each other using the natural topology of the Internet.

Classical versus Transparent IP Proxies

Abstract: Many modern IP security systems (also called "firewalls" in the trade) make use of proxy technology to achieve access control. This document explains "classical" and "transparent" proxy techniques and attempts to provide rules to help determine when each proxy system may be used without causing problems.

17 Errors-in-variables problems in financial models

Abstract: Publisher Summary The errors-in-variables (EIV) problems in finance arise from using incorrectly measured variables or proxy variables in regression models. Errors in measuring the dependent variables are incorporated in the disturbance term and they cause no problems. However, when an independent variable is measured with error, this error appears in both the regressor variable and in the error term of the new regression model. This chapter discusses several problems in financial models caused by errors-in-variables and use of proxies. The chapter also examines alternative models and techniques that can be employed to mitigate the problems because of errors-in-variables. As noted in the different places, several important gaps exist in the financial literature. Many models in finance use grouping methods to mitigate error-in-variables problems. This approach can be viewed as the use of instrumental variable (IV) methods. Therefore, it is appropriate to make use of the recent econometrics literature on instrumental variables, which discusses the problem of poor instruments, judging instrument relevance, and choice among several instruments. Use can be made of the vast econometrics literature on latent and unobservable variables because the use of proxy variables for unobservables is also very pervasive. For instance, MIMIC models are not used as often as they should be. Also, the interrelationships and comparative performance of MIMIC models, ANN models and factor analytic models with measurement errors need to be studied.

Optimizing Response Time, Rather than Hit Rates, of WWW Proxy Caches

Abstract: (ABSTRACT) This thesis investigates the possibility of improving World Wide Web (WWW) proxy cache performance. Most published research on proxy caches is concerned only with improving the cache hit rate. Improving only the hit rate, however, ignores the actual retrieval times experienced by WWW browser users. This research investigates removal algorithms that consider the time to download a file as a factor. Our experiments show that a removal algorithm that minimizes only the download time yields poor results. However, a new algorithm is investigated that does provide improved performance over common removal algorithms using three factors — the speed at which a file is downloaded, the size of the file, and the number of references to the file (the number of hits). Experiments are conducted with a modified version of the Harvest Cache which has been made available on the Internet from the Virginia Tech Network Research Group's (VT-NRG) home page. WWW traffic from the " .edu " domain is used in all of the experiments. Five different removal algorithms are compared: least recently used, least frequently used, document size, and two new algorithms. The results indicate that the new three factor algorithm reduces the average latency experienced by users. ACKNOWLEDGEMENTS I would to like thank Professor Marc Abrams, my advisor, for his hours of advice, proof reading, and direction throughout the research period. I would also like to thank the members of my thesis committee Professors Edward Fox and Scott Midkiff along with many others including for their valuable comments and suggestions. Anawat Chankhunthod, at USC, answered my questions related to the software of the Harvest Cache. Tommy Johnson ported my work to the RS6000 and wrote WebJamma to fire accelerated log files at the proxies running in parallel on the RS6000 machine. Andy Wick was always there to help when my machine died and refused to return to life. The Computer Science department at Virginia Tech funded me throughout my graduate studies. IBM donated, to Virginia Tech, the RS6000 machine used in some of the experiments. Finally, Jennifer, my wife, was always there to give moral support when problems occurred. iii To Jennifer, my wife.

Population growth, factor accumulation, and productivity

Abstract: In research on how population growth affects economic performance, some researchers stress that population growth reduces the natural resources and capital (physical and human) per worker while other researchers stress how greater population size and density affect productivity. Despite these differing theoretical predictions, the empirical literature hs focused mainly on the relationship between population growth and output per person (or crude proxies for factor accumulation). It has not decomposed the effect of population through factor accumulation and the effect through productivity. The author uses newly created cross-country, time-series data on physical capital stocks and the educational stock of the labor force to establish six findings: There is no correlation between the growth of capital per worker and population growth. The common practice of using investment rates as a proxy for capital stock growth rates is completely unjustified, as the two are uncorrelated across countries. There is either no correlation, or a weak positive correlation, between the growth of years of schooling per worker and the population growth rate. Enrollment rates are even worse as a crude proxy for the expansion of the educational capital stock, as the two are negatively correlated. There is no correlation, or a weak negative correlation, between measures of total factory productivity growth and population growth. Nearly all of the weak correlation between the growth of output per person and population growth is the result of shifts in participation in the labor force, not of changes in output per worker.

Economies of Scale and Degree of Capacity Utilization. Evidence from Retail Banks in Argentina

Abstract: The permanent income/transitory income distinction from consumption functions can be applied to cost functions. Transitory deviations of actual output from potential output, i.e. variations in capacity utilization, are relevant for the pattern of U-shaped average costs found in econometric studies. Data from retail banks in Argentina are used to illustrate this issue, with the number of branches as a proxy for potential output, and product per branch as a proxy for the utilization level. Economies of scale at the plant level can be reinterpreted as an indication of excess capacity in the banking industry.

Diet by proxy

Abstract: OOD hypersensitivity reactions by inhalation F have been described in the literature, though infrequently (1, 2). In particular, there have been very few descriptions of patients with hypersensitivity reactions from inhalation of milk proteins. This possibility has been well described in the occupational setting (3), and the case was recently reported in Sardinia of a farmer who developed anaphylaxis while milking his sheep. The same report mentions a news report of a 20-year-old woman allergic to milk who died just a few minutes after entering a dairy from severe systemic anaphylaxis caused by ingestion and/or contact with milk (4). We report the case of a 6-year-old boy referred for repeated episodes of acute bronchospasm and nasal symptoms related to inhalation of milk proteins. The reactions were so strong that his younger brother, who was nonallergic, also had to follow a diet of soy milk.

Discussion: “Reporting Choice and the 1992 Proxy Disclosure Rules”:

Abstract: This study examines the reporting of managerial stock options in corporate proxy statements. The data relate to 1992, the year in which new disclosure rules were enacted by the SEC. The main hypothesis is that, concerned with adverse public reaction and other ‘‘political costs” of excessive compensation, managers will use their discretion under SEC rules to report relatively low compensation levels. The author concludes that the empirical evidence corroborates the hypothesis. This study can be classified in accounting research within the paradigm of “management of information.” This is the research strand that examines whether and to what extent managers publicly report information that is different from “true values” to achieve certain objectives. Starting with income smoothing believed to affect investors’ risk perceptions, this literature went on to examine possible reporting manipulations to affect the decisions of regulators, labor unions, and board compensation committees, among others. In this context, the current study conjectures that within the leeway permitted, managers will report low stock option values, since they are concerned with the public’s and investors’ adverse reaction to excessive compensation. The common problem facing the “management of information” research is that the true (underlying) values of the reported variables are generally unknown and therefore must be proxied for to determine overor underreporting. This is also a problem with the current study, since the true value of the options granted to managers is unknown to the researcher, and probably also to managers (it is well known that there is yet no satisfactory way to reliably estimate the value of such options). Absent true values, it is impossible to examine directly the hypothesis that managers report lower-than-true values of stock options. The author, therefore, must resort to the somewhat weaker relational (indirect) hypotheses, such that managers are more likely to report grant-date values as the ratio of grant-date value to potential value is lower. Although these hypotheses are reasonable, we never really know whether managers underreport stock options values. Having found the hypotheses reasonable, let me turn to the data. I am troubled by the finding (Table 1) that only one third of the sample companies chose to report grant-date values (two thirds reported potential value). If, as hypothesized, managers strive to minimize the reported value of stock options, and given (Table 2) that grant-date values are only 25-32 percent of potential values, should not one expect to observe a much larger (than one third) proportion of firms reporting grant-