On The Security of Individual Data

We will consider the following problem in this paper: Assume that there are n numerical data {x(1),x(2),.., x(n)} (like salaries of n individuals) stored in a database and some subsums of these numbers are made public or just available for persons not eligible to learn the original data. Our motivating question is: At most how many of these subsums may be disclosed such that none of the numbers x1; x2;...; xn can be uniquely determined from these sums. These types of problems arise in the cases when certain tasks concerning a database are done by subcontractors who are not eligible to learn the elements of the database, but naturally should be given some data to fulfill there task. In database theory such examples are called statistical databases as they are used for statistical purposes and no individual data are supposed to be obtained using a restricted list of SUM queries. This problem was originally introduced by [ 1], originally solved by Miller et al. [ 7] and revisited by Griggs [ 4, 5]. It was shown in [ 7] that no more than ((n)(n/2)) subsums of a given set of secure data may be disclosed without disclosing at least one of the data, which upper bound is sharp as well. To calculate a subsum, it might need some operations whose number is limited. This is why it is natural to assume that the disclosed subsums of the original elements of the database will contain only a limited number of elements, say at most k. The goal of the present paper is to determine the maximum number of subsums of size at most k which can be disclosed without making possible to calculate any of the individual data x(i). The maximum is exactly determined for the case when the number of data is much larger than the size restriction k

Unconditional security at a low cost

By simulating four quantum key distribution (QKD) experiments and analyzing one decoy-state QKD experiment, we compare two data post-processing schemes based on security against individual attack by L\"{u}tkenhaus, and unconditional security analysis by Gottesman-Lo-L\"{u}tkenhaus-Preskill. Our results show that these two schemes yield close performances. Since the Holy Grail of QKD is its unconditional security, we conclude that one is better off considering unconditional security, rather than restricting to individual attacks.Comment: Accepted by International Conference on Quantum Foundation and Technology: Frontier and Future 2006 (ICQFT'06

Confronting objections to performance pay: A study of the impact of individual and gain-sharing incentives on the job satisfaction of British employees

The increasing interest in incentive pay schemes in recent years has raised concerns regarding their potential damaging effect on intrinsic job satisfaction, or the security of employment. This study explores the impact of both individual and gain-sharing incentives on the overall job satisfaction of workers in the UK, as well as their satisfaction with various facets of jobs, namely total pay, job security, and the actual work itself. Using data from six waves (1998-2003) of the British Household Panel Survey (BHPS), and after correcting for the sorting problem that arises, no significant difference in overall job utility is found between those receiving performance-related pay (PRP) and those on other methods of compensation. In addition, non-economic arguments that PRP crowds-out the intrinsic satisfaction of jobs are also not supported, as are popular concerns regarding the adverse impact of PRP schemes on job security. An important asymmetry in the manner in which individual and gain-sharing incentives affect the utility of employees is nonetheless unearthed, as the latter are consistently found to have a positive effect on employee well-being

Is there a positive incentive effect from privatizing social security : evidence from Latin America

There is increasing concern among policymakers that social security reforms that involve a transition to individual retirement savings accounts may exclude certain groups of workers from coverage against the risk of poverty in old age. While most public pay-as-you-go systems pool the risk of interrupted careers and periods of low earnings over the covered population, the reformed systems shift the burden of these risks to the individual. Adequate coverage under a system of individual retirement accounts depends critically on accumulating sufficient savings through regular contributions. In developing countries where opportunities for unregulated employment abound and workers can easily escape mandated social insurance, theory suggests that reforms will increase the number of contributors to social security by reducing distortions and improving incentives in the labor market. Motivated primarily by fiscal pressures stemming from the deficits of overly generous, poorly administered public pension systems, many governments are going ahead with reforms as if this theory is correct. Does a shift to individual retirement accounts improve the incentives to contribute to social security? Almost a decade after reforms to national social security systems in Latin America (two decades, in the case of Chile), existing evidence is mixed. Several studies have found that the share of the Chilean workforce covered by the national pension system has increased since individual retirement accounts were installed in 1981; others have shown that there has been no change in this share. But these studies rely on simulations or on casual observation of data on the sectoral allocation of the labor force and relate only to Chile. Sufficient time has now passed since reforms in several Latin American countries to allow more rigorous testing of the theory. The author estimates the impact of social security reform-specifically, the transition from a purely public pay-as-you-go system to one with private individual retirement accounts-on the share of the workforce that contributes to formal retirement security systems. To test the predictions of a simple model of a segmented labor market, he exploits variation in data from a panel of 18 Latin American countries, observed from 1980 to 1999. Results show that introducing individual retirement accounts has a positive incentive effect that, other things equal, increases the share of the economically active population contributing to the reformed system. But this effect occurs only gradually as employers and workers become familiar with the new set of social security institutions put in place by reform.Health Economics&Finance,Labor Policies,Environmental Economics&Policies,Pensions&Retirement Systems,Public Health Promotion,Environmental Economics&Policies,Pensions&Retirement Systems,Health Economics&Finance,Banks&Banking Reform,Health Monitoring&Evaluation

European welfare state under the policy "make work pay" : Analysis with composite indicators

The social security systems in 22 European countries are evaluated with a specially constructed indicator. It is based on a census-simulating model which combines both empirical (statistical) and normative (rule-based) approaches. The individual answers of unemployed on social security benefits are normatively derived from their personal situations with the OECD Tax-Benefit Models. The empirical data about personal situations are available from EuroStat. The goal is estimating the national average of net replacement rates (NRR) for unemployed persons. Such an indicator of social security shows the average degree with which social benefits compensate the loss of previous earnings. Thus, the paper suggests: -(Methodology) a model of census simulation combining statistical data on the population with individual answers computed with a rule-based model, -(Indicator) an integral quantitative evaluation of social security in Europe, which reveals its total decline by 2004 contrary to institutional improvements, -(Analysis) an explanation of the decline by a structural change of European labour markets with rapidly growing `atypical' employment groups (= part-time, temporary, self-employed, etc.) with a lower eligibility to social benefits than normally employed (= permanently full-time), -(Policy implications) a possible resolution of European policy contradictions by the "basic income model" with "flexinsurance". --Composite indicators,social security,European welfare state,European Union,"make work pay" policy

Employee Perception on Commitment Oriented Work Systems

Human resource management (HRM) does matter! Prior empirical research, summarized and classified in the work of Delery and Doty (1996), Guest (1997) and Boselie et al. (2000), suggests significant impact of HRM on the competitive advantage of organizations. The mainstream research on this topic reveals encouraging results on organizational level. Further research on the perception of the individual employee may reveal new insights in the effectiveness of HRM in organizations. Now we have the opportunity to study recent empirical data of a Dutch employment agency. These data on individual employee level provide us new insights in the perception of commitment oriented HR systems and their relationship with perceived job security and employee trust. High scores on employee participation, payment system, training and development, information sharing, and support of the direct supervisor result in employee trust and high scores on perceived job security.human resource management;performance;commitment (versus control) systems;employee trust;perceived job security

Investors’ Behavioural Biases and the Security Market: An Empirical Study of the Nigerian Security Market

Behavioural biases describe a replicable pattern in perceptual distortion, inaccurate judgment, illogical interpretation, or what is broadly called irrationality. This paper adopts a primary data approach to investigate the effects of behavioural biases on security market performance in Nigeria. The objectives are in twofold: one, to examine the extent of behavioural biases among security market investors in Nigeria and, to examine the effects of behavioural biases on stock market performance in Nigeria. The paper employed questionnaire as instrument and the technique of correlation with Pearson Product Moment Coefficient to analyze a survey of 300 randomly selected investors in Nigeria security market. We find strong evidence that behavioural biases exists but not so dominant in the Nigeria security market because a weak negative relationship exists between behavioural biases and stock market performance in Nigeria. The paper recommends that individual investors in the market should engage the services of investment advisors which will reduce personal biases in the management of their portfolios

PresenceSense: Zero-training Algorithm for Individual Presence Detection based on Power Monitoring

Non-intrusive presence detection of individuals in commercial buildings is much easier to implement than intrusive methods such as passive infrared, acoustic sensors, and camera. Individual power consumption, while providing useful feedback and motivation for energy saving, can be used as a valuable source for presence detection. We conduct pilot experiments in an office setting to collect individual presence data by ultrasonic sensors, acceleration sensors, and WiFi access points, in addition to the individual power monitoring data. PresenceSense (PS), a semi-supervised learning algorithm based on power measurement that trains itself with only unlabeled data, is proposed, analyzed and evaluated in the study. Without any labeling efforts, which are usually tedious and time consuming, PresenceSense outperforms popular models whose parameters are optimized over a large training set. The results are interpreted and potential applications of PresenceSense on other data sources are discussed. The significance of this study attaches to space security, occupancy behavior modeling, and energy saving of plug loads.Comment: BuildSys 201

Redistribution and insurance in the German welfare state

Welfare states redistribute both between individuals (inter-individual redistribution) reducing annual, cross-sectional inequality and over the lifecycle of an individual (intra-individual redistribution) insuring individuals against income risks in the long-term. But studies measuring redistribution often focus on a one-year period and the second aspect is neglected. To quantify both inter- and intra-individual redistribution in Germany this study uses SOEP data from 1984 to 2009 to construct long-term incomes over a 20-year period. Results show that annual, cross-sectional inequality is higher than inequality in the long-run, but the effect of redistribution is also larger annually than in the long-term. Depending on age the distributional focus of the German welfare state differs. When persons are young, state intervention reduces income differences between individuals mainly through the progressive tax system. Getting older and reaching retirement age income-smoothing redistribution via social security pensions becomes central. --long-term income inequality,income redistribution,social security