Model-based Utility Functions

Orseau and Ring, as well as Dewey, have recently described problems, including self-delusion, with the behavior of agents using various definitions of utility functions. An agent's utility function is defined in terms of the agent's history of interactions with its environment. This paper argues, via two examples, that the behavior problems can be avoided by formulating the utility function in two steps: 1) inferring a model of the environment from interactions, and 2) computing utility as a function of the environment model. Basing a utility function on a model that the agent must learn implies that the utility function must initially be expressed in terms of specifications to be matched to structures in the learned model. These specifications constitute prior assumptions about the environment so this approach will not work with arbitrary environments. But the approach should work for agents designed by humans to act in the physical world. The paper also addresses the issue of self-modifying agents and shows that if provided with the possibility to modify their utility functions agents will not choose to do so, under some usual assumptions.Comment: 24 pages, extensive revision

A search for HI in five elliptical galaxies with fine structure

We report on VLA H I spectral line observations of five early-type galaxies classified as optically peculiar because of the presence of jets, ripples, or other optical fine structure. We detect H I within the primary beam (30' half-power beamwidth) in four of the five systems. However, in only one case is this gas associated with the targeted elliptical galaxy. In the other cases the H I is associated with a nearby gas-rich disk or dwarf galaxy. The one H I detection is for NGC 7626, where we tentatively detect an H I cloud lying between 20 and 40 kpc southwest of the galaxy center. Its origin is unclear. Our failure to detect obvious tidal H I features suggests that if these fine-structure elliptical galaxies are remnants of disk galaxy mergers, either the progenitors were gas-poor or they are well evolved and any gaseous tidal features have dispersed and/or been converted into other phases. Our targeted systems all reside in groups or clusters, and it seems likely that tidal H I is shorter lived in these environments than suggested by studies of more isolated merger remnants

Siting Power Plants: Recent Experience in California and Best Practices in Other States

Compares California's power plant siting with results in other states. Includes interviews with California state agency representatives, developers and process mediators. Part of a series of research reports that examines energy issues facing California

Luminosity Profiles of Merger Remnants

Using published luminosity and molecular gas profiles of the late-stage mergers NGC 3921, NGC 7252 and Arp 220, we examine the expected luminosity profiles of the evolved merger remnants, especially in light of the massive CO complexes that are observed in their nuclei. For NGC 3921 and NGC 7252 we predict that the resulting luminosity profiles will be characterized by an r^{1/4} law. In view of previous optical work on these systems, it seems likely that they will evolve into normal ellipticals as regards their optical properties. Due to a much higher central molecular column density, Arp 220 might not evolve such a ``seamless'' light profile. We conclude that ultraluminous infrared mergers such as Arp 220 either evolve into ellipticals with anomalous luminosity profiles, or do not produce many low-mass stars out of their molecular gas complexes.Comment: Final refereed version. Note new title. 4 pages, 2 encapsulated color figures, uses emulateapj.sty. Accepted to ApJL. Also available at http://www.cv.nrao.edu/~jhibbard/Remnants/remnants.htm

The Apparent Morphology of Peculiar Galaxies at Intermediate to High Redshifts

We use rest frame ultraviolet (UV), B, and V band images of five nearby (z<0.02) interacting and/or starbursting galaxies to simulate deep HST observations of peculiar galaxies at medium to high redshifts. In particular, we simulate Hubble Deep Field (HDF) observations in the F606W and F814W filters of starburst galaxies in the redshift range z~0.5---2.5 by explicitly account for the combined effects of band-shifting and surface brightness dimming. We find that extended morphological features remain readily visible in the long exposures typical of the HDF out to redshifts of ~ 1. For systems above z~1.5, the simulated morphologies look remarkably similar to those of the faint objects found in the HDF and other deep HST fields. Peculiar starburst galaxies therefore appear to be the best local analogs to the highest redshift galaxies in terms of morphology, star formation rates, and spectral energy distributions. Nevertheless, photometric measurements of the z>1.5 images fail to recover the true global properties of the underlying systems. This is because the high-z observations are sensitive to the rest-frame UV emission, which is dominated by the most active star forming regions. The extended distribution of starlight from more evolved populations would not be detected. We conclude that imaging observations in the restframe UV alone cannot reveal whether high-z systems (z>1.5) are proto-galaxies, proto-bulges, or starbursts within a pre-existing population. Definitive statements regarding the global properties and dynamical states of these objects require deep imaging observations at longer wavelengths.Comment: 15 pages, AAS LaTex macros v4.0, 6 Figs. To appear in The Astronomical Journal. 1200 kB gzipped encapsulated postscript file of paper and high-resolution figures is available at http://www.ifa.hawaii.edu/~hibbard/highZ/ or http://www.ifa.hawaii.edu/~vacca/highz.htm

An HI Threshold for Star Cluster Formation in Tidal Debris

Super star clusters are young, compact star clusters found in the central regions of interacting galaxies. Recently, they have also been reported to preferentially form in certain tidal tails, but not in others. In this paper, we have used 21 cm HI maps and the Hubble Space Telescope Wide Field Planetary Camera 2 images of eight tidal tail regions of four merging galaxy pairs to compare the kiloparsec scale HI distribution with the location of super star clusters found from the optical images. For most of the tails, we find that there is an increase in super star cluster density with increasing projected HI column density, such that the star cluster density is highest when log N(HI) >= 20.6 cm^{-2}, but equal to the background count rate at lower HI column density. However, for two tails (NGC 4038/39 Pos A and NGC 3921), there is no significant star cluster population despite the presence of gas at high column density. This implies that the N(HI) threshold is a necessary but not sufficient condition for cluster formation. Gas volume density is likely to provide a more direct criterion for cluster formation, and other factors such as gas pressure or strength of encounter may also have an influence. Comparison of HI thresholds needed for formation of different types of stellar structures await higher resolution HI and optical observations of larger numbers of interacting galaxies.Comment: 19 pages, 6 figures, 3 tables, accepted for publication in MNRA

How Engaged Are Consumers in Their Health and Health Care, and Why Does It Matter?

Summarizes findings on U.S. patients' ability to manage their health and health care by income level, education, Medicaid status, and health status. Examines access to care by level of engagement among the chronically ill. Discusses policy implications

Avoiding Wireheading with Value Reinforcement Learning

How can we design good goals for arbitrarily intelligent agents? Reinforcement learning (RL) is a natural approach. Unfortunately, RL does not work well for generally intelligent agents, as RL agents are incentivised to shortcut the reward sensor for maximum reward -- the so-called wireheading problem. In this paper we suggest an alternative to RL called value reinforcement learning (VRL). In VRL, agents use the reward signal to learn a utility function. The VRL setup allows us to remove the incentive to wirehead by placing a constraint on the agent's actions. The constraint is defined in terms of the agent's belief distributions, and does not require an explicit specification of which actions constitute wireheading.Comment: Artificial General Intelligence (AGI) 201