Discounting of reward sequences: a test of competing formal models of hyperbolic discounting

Humans are known to discount future rewards hyperbolically in time. Nevertheless, a formal recursive model of hyperbolic discounting has been elusive until recently, with the introduction of the hyperbolically discounted temporal difference (HDTD) model. Prior to that, models of learning (especially reinforcement learning) have relied on exponential discounting, which generally provides poorer fits to behavioral data. Recently, it has been shown that hyperbolic discounting can also be approximated by a summed distribution of exponentially discounted values, instantiated in the μAgents model. The HDTD model and the μAgents model differ in one key respect, namely how they treat sequences of rewards. The μAgents model is a particular implementation of a Parallel discounting model, which values sequences based on the summed value of the individual rewards whereas the HDTD model contains a non-linear interaction. To discriminate among these models, we observed how subjects discounted a sequence of three rewards, and then we tested how well each candidate model fit the subject data. The results show that the Parallel model generally provides a better fit to the human data

Unsupervised Learning of Depth and Ego-Motion from Video

We present an unsupervised learning framework for the task of monocular depth and camera motion estimation from unstructured video sequences. We achieve this by simultaneously training depth and camera pose estimation networks using the task of view synthesis as the supervisory signal. The networks are thus coupled via the view synthesis objective during training, but can be applied independently at test time. Empirical evaluation on the KITTI dataset demonstrates the effectiveness of our approach: 1) monocular depth performing comparably with supervised methods that use either ground-truth pose or depth for training, and 2) pose estimation performing favorably with established SLAM systems under comparable input settings.Comment: Accepted to CVPR 2017. Project webpage: https://people.eecs.berkeley.edu/~tinghuiz/projects/SfMLearner

Building Structures from Mycelium

The purpose of this project was to develop a method for creating bricks from mycelium and agricultural waste. The bulk of the research happened in two parts, the first part being a period in which different substrates, strains, and methods were used build the bricks. This research took place in San Luis Obispo and was aided by a group of students in PSC392 under Dr. Pete Schwartz in early 2022. After developing a method for constructing these bricks, the research was moved to St. Thomas, Jamaica, in collaboration with an ecovillage called The Source Farm from July to September. The method developed is cheap, easy to learn, scalable, and the bricks that were produced in the US were sturdy, however due to the environmental conditions in Jamaica, this method did not work as well. All bricks made in Jamaica became contaminated from molds and bugs or died as a result of high temperatures. It’s believed that the method developed could work in Jamaica during a cooler part of the year, or with more climate controllability

Leek Variety Trial 2014

Megaton was an excellent performer for yield both years, with strong establishment and uniformly large leeks. DP-12-02 and Tadorna also did well both years; moderate yields are due to the smaller size of these leeks relative to Megaton. DP-12-02 is a very tall, thin, green leek that is well suited to bunching sales in late summer and early fall, but loses quality when harvested late. Tadorna and Autumn Giant were the most winter hardy, and were generally good performers except for a tendency to variable size and a high percentage of unmarketably small leeks. Rally was only tested in 2013 but shows real promise as a leek for fall harvest

Onion Variety Trial 2014

In 2012 we trialed 18 yellow storage onion varieties, three red onion varieties, and one sweet onion. The 2013 trial included 17 yellow storage onion varieties, 3 sweet yellow onion varieties, one sweet white variety, and 7 red onion varieties. The onion varieties were evaluated for yield, quality, storability, and suitability to plasticulture. All of the onions were started from seed in the greenhouse and transplanted into raised beds covered with plastic mulch. In 2012 transplanting took place on April 13 and beds were covered with conventional plastic mulch. In 2013 transplanting took place on April 30 and beds were covered with biodegradable BioTelo plastic mulch. In major production areas onions are direct-seeded into bare ground, however, this production system requires extensive use of herbicides and frequent hand weeding. The use of transplants and plastic mulch essentially eliminates weeding within the beds. Varieties differ in how reliably the bulbs form above the mulch, and bulbs that form partly or entirely below the mulch are at increased risk of thrips damage, bulb rot, and mis-shaped bulbs. Each 4-ft bed contained 3 rows of onions, with an in-row spacing of 4 inches. All fertilizers were incorporated during bed construction; water was provided by rainfall supplemented with overhead irrigation

Leek Variety Trials, 2012

Variety trial of leek varieties conducted at Kingston, RI, in 2012

Garlic Variety Trial 2014

Based on the 2012-13 results, soft neck garlic is a viable crop for southern New England. The best varieties did as well as the best hard neck varieties. For both types of garlic approximately ¼ of the bulbs were culled because of insufficient size. The cause of the small bulbs is unclear; they may have been due to competition from the oats that failed to winter kill, or they may have been because the planting stock had not adapted to our conditions. Bulb rot is more of a problem with soft neck garlic, but appears to be controllable with careful selection of varieties. The larger trial and colder winter in 2013-14 should provide more information on the suitability of soft neck garlic

Effect of Sulfur Amendments on Yield and Quality in Alliums

In conclusion, sulfur fertilization appears to offer little or no benefit for allium vegetables in Rhode Island. Variety differences were much greater than the fertility effects, and growers who are experiencing issues with yield and storage life are encouraged to consider switching to better varieties