Policy and Practice Brief: Administrative Offsets and Social Security Benefits

This brief provides a summary of the Anti-Assignment Clause of the Social Security Act and administrative offsets. It provides a description of the child support offset, food stamp dept offset, student loan offset, and interim assistance recoupment. It concludes with a discussion of implications for BPA&O and PABSS programs

The BaBar Event Building and Level-3 Trigger Farm Upgrade

The BaBar experiment is the particle detector at the PEP-II B-factory facility at the Stanford Linear Accelerator Center. During the summer shutdown 2002 the BaBar Event Building and Level-3 trigger farm were upgraded from 60 Sun Ultra-5 machines and 100MBit/s Ethernet to 50 Dual-CPU 1.4GHz Pentium-III systems with Gigabit Ethernet. Combined with an upgrade to Gigabit Ethernet on the source side and a major feature extraction software speedup, this pushes the performance of the BaBar event builder and L3 filter to 5.5kHz at current background levels, almost three times the original design rate of 2kHz. For our specific application the new farm provides 8.5 times the CPU power of the old system.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, 1 eps figure, PSN MOGT00

Survival of the d-wave superconducting state near the edge of antiferromagnetism in the cuprate phase diagram

In the cuprate superconductor $YBa_2Cu_3O_{6+x}$, hole doping in the $CuO_2$ layers is controlled by both oxygen content and the degree of oxygen-ordering. At the composition $\rm YBa_2Cu_3O_{6.35}$, the ordering can occur at room temperature, thereby tuning the hole doping so that the superconducting critical temperature gradually rises from zero to 20 K. Here we exploit this to study the c-axis penetration depth as a function of temperature and doping. The temperature dependence shows the d-wave superconductor surviving to very low doping, with no sign of another ordered phase interfering with the nodal quasiparticles. The only apparent doping dependence is a smooth decline of superfluid density as Tc decreases.Comment: 4 pages, 3 figure

Five criteria for choosing among poverty programs

The author addresses the issue of how to choose among discreet poverty interventions such as food stamp programs, public works, or small enterprise credit schemes where little formal policy modeling is done prior to decisionmaking. The minimum criteria on which to judge the relative merits of poverty programs are the following. Administrative feasibility. This depends on the detailed designof the program, the level of resources available for administration, and the degree of imperfection that can be tolerated. Political feasibility. This depends on how the program is promoted to the public, how coalitions of supporters or detractors are built, and the relative power of beneficiaries, suppliers, and administrators. Collateral effects on the poverty strategy. How will a safety net program affect, for example, the participants'labor supply, participation in other programs, and receipt of private interhousehold transfers, and how will those changes affect markets and government finances? What will be the net effect on poverty reduction. Potential for targeting the poor. Will the program reach significant number of the poor? How much leakage of benefits will there be to the nonpoor? Tailoring the solution to the problem. The program choice should address the real problem. Where the poor have suffered a loss of real wages rather than a loss of jobs, for example, transfers to the working poor may be more relevant than creating jobs. This criterion may seem obvious, but many proposals seem to ignore it. The author illustrates her main points by applying these criteria to a range of poverty programs commonly used in Latin America. General subsidies of food prices, for example, are administratively and politically feasible and lower food costs to the consumer, but they may distort the economy, harming growth. Food stamps are easy to target to the poor, are fairly difficult to administer, depending on program design, but depending on program design, may encourage the use of schools and primary health care. But there is controversy about whether they encourage dependency and diminish the work ethic.Rural Poverty Reduction,Environmental Economics&Policies,Health Economics&Finance,Services&Transfers to Poor,Safety Nets and Transfers

Constructing fail-controlled nodes for distributed systems: a software approach

PhD ThesisDesigning and implementing distributed systems which continue to provide specified services in the presence of processing site and communication failures is a difficult task. To facilitate their development, distributed systems have been built assuming that their underlying hardware components are Jail-controlled, i.e. present a well defined failure mode. However, if conventional hardware cannot provide the assumed failure mode, there is a need to build processing sites or nodes, and communication infra-structure that present the fail-controlled behaviour assumed. Coupling a number of redundant processors within a replicated node is a well known way of constructing fail-controlled nodes. Computation is replicated and executed simultaneously at each processor, and by employing suitable validation techniques to the outputs generated by processors (e.g. majority voting, comparison), outputs from faulty processors can be prevented from appearing at the application level. One way of constructing replicated nodes is by introducing hardwired mechanisms to couple replicated processors with specialised validation hardware circuits. Processors are tightly synchronised at the clock cycle level, and have their outputs validated by a reliable validation hardware. Another approach is to use software mechanisms to perform synchronisation of processors and validation of the outputs. The main advantage of hardware based nodes is the minimum performance overhead incurred. However, the introduction of special circuits may increase the complexity of the design tremendously. Further, every new microprocessor architecture requires considerable redesign overhead. Software based nodes do not present these problems, on the other hand, they introduce much bigger performance overheads to the system. In this thesis we investigate alternative ways of constructing efficient fail-controlled, software based replicated nodes. In particular, we present much more efficient order protocols, which are necessary for the implementation of these nodes. Our protocols, unlike others published to date, do not require processors' physical clocks to be explicitly synchronised. The main contribution of this thesis is the precise definition of the semantics of a software based Jail-silent node, along with its efficient design, implementation and performance evaluation.The Brazilian National Research Council (CNPq/Brasil)