Integer symmetric matrices having all their eigenvalues in the interval [-2,2]

We completely describe all integer symmetric matrices that have all their eigenvalues in the interval [-2,2]. Along the way we classify all signed graphs, and then all charged signed graphs, having all their eigenvalues in this same interval. We then classify subsets of the above for which the integer symmetric matrices, signed graphs and charged signed graphs have all their eigenvalues in the open interval (-2,2).Comment: 33 pages, 18 figure

Network, system, and status software enhancements for the autonomously managed electrical power system breadboard. Volume 3: Commands specification

This volume (3 of 4) contains the specification for the command language for the AMPS system. The volume contains a requirements specification for the operating system and commands and a design specification for the operating system and command. The operating system and commands sits on top of the protocol. The commands are an extension of the present set of AMPS commands in that the commands are more compact, allow multiple sub-commands to be bundled into one command, and have provisions for identifying the sender and the intended receiver. The commands make no change to the actual software that implement the commands

Audit Certainty, Audit Productivity, and Taxpayer Compliance

Strategies for dealing with evasion include such standard policies as stricter enforcement (e.g., increased audit rates, more extensive audits, larger penalties). However, the exact responses of taxpayers to these enforcement measures are quite difficult to measure with existing field data, and so are not known precisely. In this paper we use experimental methods to examine how individuals respond in their compliance decisions to a "certain" probability of audit and to information concerning the "productivity" of an audit. Our design informs some individuals that their return will be audited with certainty prior to making their compliance decision, while other individuals receive information that they will not be audited; we also inform individuals of the productivity of the audit by stating how much unreported income will be discovered via the audit. We find that the announcement of audits increases the compliance rate of those who are told that they will be audited. However, the compliance rate of those who know that they will not be audited falls, and the net effect is that overall compliance falls. Working Paper 06-4

A graphical, rule based robotic interface system

The ability of a human to take control of a robotic system is essential in any use of robots in space in order to handle unforeseen changes in the robot's work environment or scheduled tasks. But in cases in which the work environment is known, a human controlling a robot's every move by remote control is both time consuming and frustrating. A system is needed in which the user can give the robotic system commands to perform tasks but need not tell the system how. To be useful, this system should be able to plan and perform the tasks faster than a telerobotic system. The interface between the user and the robot system must be natural and meaningful to the user. A high level user interface program under development at the University of Alabama, Huntsville, is described. A graphical interface is proposed in which the user selects objects to be manipulated by selecting representations of the object on projections of a 3-D model of the work environment. The user may move in the work environment by changing the viewpoint of the projections. The interface uses a rule based program to transform user selection of items on a graphics display of the robot's work environment into commands for the robot. The program first determines if the desired task is possible given the abilities of the robot and any constraints on the object. If the task is possible, the program determines what movements the robot needs to make to perform the task. The movements are transformed into commands for the robot. The information defining the robot, the work environment, and how objects may be moved is stored in a set of data bases accessible to the program and displayable to the user

Do Individuals Comply on Income Not Reported by Their Employer

Individuals (e.g., the self-employed and those earning casual wages such as tips) with income not reported to the tax authority by a third party may be less likely to be detected evading taxes relative to the case in which their income is subject to third-party reporting. However, their compliance responses - to changes in the proportion of income that is reported to the tax authority, to changes in audit and tax rates, and so on - are largely unknown, in part because of the difficulty in obtaining information on individual choices in these situations. We use experimental methods to examine individual income tax compliance in settings where individuals differ in the portion of their income that is "matched" (or reported to the tax authority via third-party information) versus "nonmatched" (or not fully reported to the tax authority). Our results indicate that individuals who have relatively more non-matched income exhibit significantly lower tax compliance rates than individuals who earn relatively less non-matched income. Our results also indicate that higher income levels, higher tax rates, and lower audit rates lead to increased tax evasion, but with responses that vary depending upon the proportion of matched versus non-matched income. Working Paper 07-3

On the average number of divisors of quadratic polynomials

décembre 19821982/12 (N269)

The Effects of Communication Among Taxpayers on Compliance

Taxpayer audits are thought to have a direct deterrent effect on the individuals actually audited. In addition, audits are believed to have an indirect deterrent effect on individuals not audited as these individuals learn (or are told) about the audits of other taxpayers. However, the effects on compliance of the ways in which taxpayers learn about - and communicate among themselves - audit rates are not known. In this study, we use laboratory experiments to examine the effects of three types of information and communication on compliance. In all sessions, each subject knows the probability of audit and the results of their own audit (if any). In our base case session, each subject knows only the result of his or her audit, and subjects receive no information about audit results of other subjects. In a second treatment (termed "official" communication), subjects are also told by the experimenter the actual number of audits conducted during a period. In a third treatment (or "unofficial" communication), subjects are offered the opportunity to send a "message" to the other participants about their audit experience. Our preliminary results indicate that "unofficial" communication has a strong indirect effect that increases compliance, but that "official" communication may not encourage voluntary compliance