Showing papers on "Proxy (statistics) published in 2007"

Identity-Based Proxy Re-encryption

Abstract: In a proxy re-encryption scheme a semi-trusted proxy converts a ciphertext for Alice into a ciphertext for Bob without seeing the underlying plaintext. A number of solutions have been proposed in the public-key setting. In this paper, we address the problem of Identity-Based proxy re-encryption, where ciphertexts are transformed from one identityto another. Our schemes are compatible with current IBE deployments and do not require any extra work from the IBE trusted-party key generator. In addition, they are non-interactive and one of them permits multiple re-encryptions. Their security is based on a standard assumption (DBDH) in the random oracle model.

Trading performance, disposition effect, overconfidence, representativeness bias, and experience of emerging market investors

Abstract: Using brokerage account data from China, we study investment decision making in an emerging market. We find that Chinese investors make poor trading decisions: the stocks they purchase underperform those they sell. We also find that Chinese investors suffer from three behavioral biases: (i) they tend to sell stocks that have appreciated in price, but not those that have depreciated in price, consistent with a disposition effect, acknowledging gains but not losses; (ii) they seem overconfident; and (iii) they appear to believe that past returns are indicative of future returns (a representativeness bias). In comparisons to prior findings, Chinese investors seem more overconfident than U.S. investors (i.e., the Chinese hold fewer stocks, yet trade very often) and their disposition effect appears stronger. Finally, we categorize Chinese investors based on proxy measures of experience and find that “experienced” investors are not always less prone to behavioral biases than are “inexperienced” ones. Copyright © 2007 John Wiley & Sons, Ltd.

Imputing Risk Tolerance from Survey Responses

Abstract: Economic theory assigns a central role to risk preferences. This paper develops a measure of relative risk tolerance using responses to hypothetical income gambles in the Health and Retirement Study. In contrast to most survey measures that produce an ordinal metric, this paper shows how to construct a cardinal proxy for the risk tolerance of each survey respondent. The paper also shows how to account for measurement error in estimating this proxy and how to obtain consistent regression estimates despite the measurement error. The risk tolerance proxy is shown to explain differences in asset allocation across households.

Are Small Innovators Credit Rationed

Abstract: Drawing upon a sample of 256 small firms who applied for bank loans, the current paper is concerned with the extent to which 'innovativeness' is associated with a lower level of loan application success. The paper records the proportion of loan successfully applied for and estimates a series of tobit models utilising a number of proxy measures for innovation (in terms of inputs, outputs, and commercial significance to the firm) and incorporating standard controls. In general, the models suggest (as anticipated) that the most innovative firms are less successful in loan markets than their less innovative peers - though there is some variation by proxy. Moreover, there is tentative evidence that 'a little innovation may be a good thing'.

Identity-based proxy re-encryption without random oracles

Abstract: A proxy re-encryption scheme allows Alice to temporarily delegate the decryption rights to Bob via a proxy. Alice gives the proxy a re-encryption key so that the proxy can convert a ciphertext for Alice into the ciphertext for Bob. In this paper, we propose two identity-based proxy re-encryption schemes, which are both proved secure in the standard model. The first one is efficient in both computation and ciphertext length, and the other one achieves chosen-ciphertext security. Our solutions answer the open problems left in the previous work.

Determinants of Child-Parent Agreement in Quality-of-Life Reports: A European Study of Children With Cerebral Palsy

Abstract: OBJECTIVES. The differences between child self-reports and parent proxy reports of quality of life in a large population of children with cerebral palsy were studied. We examined whether child characteristics, severity of impairment, socioeconomic factors, and parental stress were associated with parent proxy reports being respectively higher or lower than child self-reports of quality of life. METHODS. This study was conducted in 2004–2005 and assessed child quality of life (using the Kidscreen questionnaire, 10 domains, each scored 0–100) through self-reports and parent proxy reports of 500 children aged 8 to 12 years who had cerebral palsy and were living in 7 countries in Europe. RESULTS. The mean child-reported scores of quality of life were significantly higher than the parent proxy reports in 8 domains, significantly lower for the finances domain, and similar for the emotions domain. The average frequency of disagreement (child-parent difference greater than half an SD of child scores) over all domains was 64%, with parents rating their child9s quality of life lower than the children themselves in 29% to 57% of child-parent pairs. We found that high levels of stress in parenting negatively influenced parents’ perception of their child9s quality of life, whereas the main factor explaining parents’ ratings of children9s quality of life higher than the children themselves is self-reported severe child pain. CONCLUSIONS. This study shows that the factors associated with disagreement are different according to the direction of disagreement. In particular, parental well-being and child pain should be taken into account in the interpretation of parent proxy reports, especially when no child self-report of quality of life is available. In the latter cases, it may be advisable to obtain additional proxy reports (from caregivers, teachers, or clinicians) to obtain complementary information on the child9s quality of life.

Quality Versus Quantity: The Case of Forward-Looking Disclosure

Abstract: Empirical studies do not make a clear distinction between the quantity and quality of disclosure. As it is generally assumed that the quantity of information has an implication in determining its quality, quantity measures are often used as proxy for disclosure quality. Nonetheless the measurement of the quality of disclosure is recognized as a relevant question that is still open and the importance of developing measures of disclosure quality is emphasised in literature. This paper disputes the idea that the quantity of disclosure is a sound proxy for the quality of disclosure. The adoption of multidimensional frameworks for the appreciation of disclosure is discussed and an index for quality disclosure is proposed. Moving from the assumption that high quality information should usefully support external users in the judgement of past and future performance, we hypothesize that high quality disclosure is positively associated with accuracy and negatively associated with the dispersion of analysts' earnings forecasts. We show analytically that the proposed framework captures dimensions of annual report disclosure that are considered useful by financial analysts in forecasting earnings and that the proposed measure of disclosure quality has a stronger positive statistical association with accuracy and a stronger negative association with the dispersion of financial analysts' earnings forecasts than a simple index of disclosure quantity has.

Proxy and self‐report agreement on the Stroke and Aphasia Quality of Life Scale‐39

Abstract: Background and purpose: Health related quality of life outcomes are increasingly used to measure the effectiveness of stroke interventions. People with severe aphasia after stroke may be unable to self-report on such measures, necessitating the use of proxy respondents. We explored the level of agreement between people with aphasia (PWA) and their proxies on the Stroke and Aphasia Quality of Life Scale (SAQOL-39) and whether this agreement is influenced by demographic variables and proxy levels of depression and carer strain. Methods: People with chronic aphasia (⩾6 months post stroke) were recruited through the UK national charity for PWA. They were interviewed on the SAQOL-39 and their nominated proxies were interviewed on the SAQOL-39, the General Health Questionnaire and the Caregiver Strain Index. Proxy respondents had to be ⩾18 years of age, see the person with aphasia at least twice a week and have no known severe mental health problems or cognitive decline. Results: 50 of 55 eligible pairs (91%) took part in the study. Proxies rated PWA as more severely affected than PWA rated themselves. The SDs of the difference scores were large and the difference was significant for three of the four SAQOL-39 domains and the overall mean (p⩽0.01). However, the bias as indicated by effect sizes was small to moderate (0.2–0.5). The strength of the agreement was excellent for the overall SAQOL-39 and the physical domain (intra-class correlation coefficient ICC 0.8), good for the psychosocial and communication domains (0.7) and fair for the energy domain (0.5). Demographic variables and proxy’s mood and carer strain did not affect the level of agreement. Conclusions: For group comparisons, proxy respondents who are in frequent contact with people with chronic aphasia can reliably report on their health related quality of life, using the SAQOL-39. Although there are significant differences between PWA and proxy responses, the magnitude of this difference is small to moderate.

Proxy card authorization system

Abstract: A system and method is provided for providing proxy access to a set of resources subject to constraints specified by the primary party having access to the resources. The system comprises one or more proxy cards associated with a proxy account that contains details on the resources available and also configurable rules for processing proxy authorization requests and returning an authorization response in dependence on the rules. The system has a particular application to payment cards and accounts, whereby the proxy card can act as proxy for one or more of the real payment cards and the proxy card authentication service may operate in a transparent manner as part of a normal overall payment authorization process.

Are Articles in “Top” Management Journals Necessarily of Higher Quality?

Abstract: This study investigates the appropriateness of using publication of an article in a top (specifically, top five) management journal as a proxy for its quality. Social Science Citation Index citatio...

Proxy card representing many monetary sources from a plurality of vendors

Abstract: A proxy card used at an ATM or at any vendor store that has a legacy point of sale unit or at a store with the smart point of sale. In general, it can be used with any vendor and otherwise as any credit or debit card might be used. The point-of sale unit interacts with a multi-source processing system (MSPS) that, instead of servicing a single money source, interacts with more than one of a plurality of monetary sources that may be associated with the proxy card. The money transferred from credit or debit accounts of the user may be either transferred directly or indirectly via a proxy central account associated with the MSPS that a user maintains.

Is free school meal status a valid proxy for socio-economic status (in schools research)?

Abstract: This paper analyses whether free school meal (FSM) status is a valid proxy for socio-economic status when conducting schools-related research.

Mobile device management proxy system

Abstract: A general-purpose proxy mobile device management architecture. The architecture serves as a proxy for a mobile client seeking services from backend systems. A virtual client image of state information associated with the mobile client is stored such that when the mobile client interacts with the proxy, the virtual image updates to the latest client state. Based on the changes to the state, the proxy system asynchronously accesses one or more arbitrary services of the backend systems on behalf of the mobile client. When the mobile client connects to the proxy, the proxy will have the latest services associated with the states of the virtual image, and updates the state of the mobile client. Updating and accessing occurs asynchronously on the frontend between the proxy and mobile devices and on the backend between the proxy and the backend systems.

The Investment Opportunity Set and its Proxy Variables

Abstract: We use a real options approach to evaluate the performance of proxy variables for a firm?s investment opportunity set. The results show that on a relative scale, the market-to-book assets ratio outperforms all other proxy variables that we investigate. It has the highest information content with respect to investment opportunities, and it is least affected by other factors. Although both the market-to-book equity and the earnings-price ratios are related to investment opportunities, they do not contain information that is not already contained in the market-to-book assets ratio. Consistent with this finding, a common factor constructed from several proxy variables does not improve the performance of the market-to-book assets ratio.

Entrepreneurship and economic growth: an empirical analysis

Abstract: This study examines the impact of entrepreneurship on economic growth by using a new variable based on patent data to proxy for productive entrepreneurship. Data on self-employment is used as an alternative proxy. The study considers 22 OECD countries and finds a positive relationship between the proposed measure of productive entrepreneurship — degree of innovativeness of different nations — and economic growth, while the alternative measure, based on self-employment, appears to be negatively correlated with economic growth. A battery of econometric specifications and techniques backs the findings.

Disclosure Interactions and the Cost of Equity Capital: Evidence From the Spanish Continuous Market

Abstract: The purpose of this paper is to provide some new evidence on the relationship between disclosure and the cost of equity capital. We propose a new specification for the empirical test based on the idea that in the previous models one crucial variable was missing: accounting policy choice. We test our theoretical hypothesis using a sample of Spanish firms quoted on the Spanish continuous market from 1999 to 2002. We adopt the ex-ante approach to measure the cost of equity capital, taking analysts predictions as a proxy for expected earnings. As an explanatory variable we use an index measuring annual report disclosure quality. This measure of disclosure is combined with a proxy for the accounting policy choice of the firm. We measure firms' conservatism using the modified Jones model of Dechow et al. (1995) to estimate discretionary accruals. Our results confirm that the relationship between disclosure and cost of capital is affected by the choice of accounting policy.

Identity-based proxy signature from pairings

Abstract: A proxy signature scheme allows an entity to delegate its signing capability to another entity (proxy) in such a way that the proxy can sign messages on behalf of the delegator. Proxy signatures have found numerous practical applications such as distributed systems, mobile agent applications, etc. Recently, Xu, Zhang and Feng proposed the first formal models of identity based proxy signature. Unfortunately, their model does not capture the notion of adaptively chosen message and chosen identity attacker in identity based system. In this paper, we redefine the security models of identity based proxy signature to capture the most stringent attacks against adaptively chosen message and chosen identity attacker. We also propose a new provably secure identity basad proxy signature scheme whose security is based on the hardness of Computational Diffie-Hellman problem in the random oracle model.

Use of external services with clusters

Abstract: A method, apparatus, and system are directed toward managing a system that includes a cluster and an external resource. The external resource may be part of a second cluster that is collocated on the same hardware platforms as the cluster. A proxy resource is used to enforce a dependency relationship between a native resource of the cluster and an external resource, such that a dependency with the proxy resource serves to enforce a dependency with the external resource. The cluster framework may maintain states of the proxy resource, including an offline state, an online-standby state, and an online state. The online-standby indicates that the proxy has been started, but it has not determined that the associated external resource is enabled. The proxy may determine whether the external resource is enabled or disabled and, in response, notify the cluster framework.

Validation of the human activity profile in stroke: a comparison of observed, proxy and self-reported scores.

Abstract: Purpose. To assess the concurrent validity of the Human Activity Profile (HAP) with stroke and healthy control individuals, when reported by the subject or a proxy and compared to observed performance, used as gold standard; factors related to discrepancies; as well as to determine variables that could best predict physical activity levels.Methods. A total of 24 stroke and 23 healthy control subjects took part in the study. Functional outcome measures included personal/demographic factors, HAP, the 10-meter walk, and cognition.Results. Strong relationships were found between self-reported and observed scores for both groups (r = 0.89 – 0.99). The relationships between proxy and observed scores were acceptable for stroke (r = 0.80 – 0.87) but lower for control subjects (r = 0.65 – 0.75), with intraclass correlation coefficients (ICCs) ranging from 0.69 – 0.89. Significant differences were found between proxy and observed scores for stroke, but not for control subjects. Discrepancies between scores showed l...

Register clustering in a sip-based network

Abstract: In one embodiment, a method can include: receiving a request for service in a first edge proxy; applying a hash function to a source address of an endpoint; and forwarding the request to a second edge proxy in response to a first result of the hash function, or servicing the request in the first edge proxy in response to a second result of the hash function.

Apparatus, system, and method for a device shared between multiple independent hosts

Abstract: An apparatus, system and method that permits for sharing a device between multiple hosts where data can be transferred between a host and the shared device over a system bus independent from other hosts connected to the system bus. A command proxy host establishes a data path between the shared device and requesting host, and then acts as proxy for selected commands used to set up a data transfer.

Self‐ and Proxy Reports Across Three Populations: Older Adults, Persons With Alzheimer’s Disease, and Persons With Intellectual Disabilities

Abstract: Self-reports are often used to determine general well-being in both research studies and practice settings. Proxy reports are also used to gain insight into the well-being of persons with physical ill-heath, cognitive impairments, or disabilities. The author reviews the utility and limitations of using self- and proxy reports across three populations: older adults, persons with Alzheimer’s disease (AD), and persons with intellectual disabilities (ID). For differing reasons, the use of self- and proxy reports often results in inaccuracies. Among older adults, the level of subjectivity in questions, type of relationship, and levels of carer burden may influence the outcomes, while increasing severity of dementia and decreased deficit awareness may affect data from persons with AD, and question formats, acquiescence, and level of intellectual development may affect data from persons with ID. However, generally, proxy reports can be useful in determining aspects of well-being in people with ID, in people with AD, and in the general older population, as long as researchers keep in mind that factors that can enhance (e.g., experiences/abilities that are more objectively assessed, and attention to question format) or diminish (e.g., experiences/abilities that are more subjectively assessed, severity of dementia, and level of ID) the quality of information obtained. With respect to the use of these techniques with people with ID, the author concludes that careful attention to survey items, especially response format and wording, can greatly enhance self-report completion and proxy concordance.

Non-parametric regression estimation from data contaminated by a mixture of Berkson and classical errors.

Abstract: Estimation of a regression function is a well-known problem in the context of errors in variables, where the explanatory variable is observed with random noise. This noise can be of two types, which are known as classical or Berkson, and it is common to assume that the error is purely of one of these two types. In practice, however, there are many situations where the explanatory variable is contaminated by a mixture of the two errors. In such instances, the Berkson component typically arises because the variable of interest is not directly available and can only be assessed through a proxy, whereas the inaccuracy that is related to the observation of the latter causes an error of classical type. We propose a non-parametric estimator of a regression function from data that are contaminated by a mixture of the two errors. We prove consistency of our estimator, derive rates of convergence and suggest a data-driven implementation. Finite sample performance is illustrated via simulated and real data examples.

Method and system for secure sharing of personal information

Abstract: A method and a system for secure sharing of personal information are provided. The system may include a communications module to receive a request for personal information of a user, a detector to determine that the request includes a proxy identification key, a matching module to determine that the proxy identification key is associated with the user, a data retrieval module to obtain the requested personal information of the user; and a delivery module to deliver the obtained personal information of the user to an originator of the request. The personal information may be associated with a permanent identification information of the user. The proxy identification key may be viewed as a substitute for the permanent identification information of the user. The proxy identification key may provide additional security by imposing certain restrictions such as the amount of data sharing.

Proxy consent: moral authority misconceived

Abstract: The Mental Capacity Act 2005 has provided unified scope in the British medical system for proxy consent with regard to medical decisions, in the form of a lasting power of attorney. While the intentions are to increase the autonomous decision making powers of those unable to consent, the author of this paper argues that the whole notion of proxy consent collapses into a paternalistic judgement regarding the other person's best interests and that the new legislation introduces only an advisor, not a proxy with the moral authority to make treatment decisions on behalf of another. The criticism is threefold. First, there is good empirical evidence that people are poor proxy decision makers as regards accurately representing other people's desires and wishes, and this is therefore a pragmatically inadequate method of gaining consent. Second, philosophical theory explaining how we represent other people's thought processes indicates that we are unlikely ever to achieve accurate simulations of others' wishes in making a proxy decision. Third, even if we could accurately simulate other people's beliefs and wishes, the current construction of proxy consent in the Mental Capacity Act means that it has no significant ethical authority to match that of autonomous decision making. Instead, it is governed by a professional, paternalistic, best‐interests judgement that undermines the intended role of a proxy decision maker. The author argues in favour of clearly adopting the paternalistic best‐interests option and viewing the proxy as solely an advisor to the professional medical team in helping make best‐interests judgements.

A Prototype Power Management Proxy for Gnutella Peer-to-Peer File Sharing

Abstract: In order to be part of a peer-to-peer (P2P) file sharing network a host must be fully powered-on all of the time. In addition to providing a user interface, a P2P host handles query messages and serves requested files. In this paper, we describe the development of a prototype Gnutella-like P2P power management proxy sub-system that handles query messages. This can allow desktop PCs acting as P2P hosts to enter a low-power sleep state for most of the time and be woken-up by the proxy only when needed to serve files. TCP connections with neighbors are maintained by the host when it is awake and by the proxy when the host is sleeping. Experiments show that a low-cost Freescale ColdFire processor can effectively proxy for a P2P host. This suggests that a controller for a Gnutella P2P proxy could be co-located on an Ethernet NIC at low cost. This could lead to significant energy savings by allowing P2P hosts to power manage into a low-power sleep state when not in active use.

Imputing Risk Tolerance from Survey Responses

Abstract: Economic theory assigns a central role to risk preferences. This paper develops a measure of relative risk tolerance using responses to hypothetical income gambles in the Health and Retirement Study. In contrast to most survey measures that produce an ordinal metric, this paper shows how to construct a cardinal proxy for the risk tolerance of each survey respondent. The paper also shows how to account for measurement error in estimating this proxy and how to obtain consistent regression estimates despite the measurement error. The risk tolerance proxy is shown to explain differences in asset allocation across households.