On the Computability of Solomonoff Induction and Knowledge-Seeking

Solomonoff induction is held as a gold standard for learning, but it is known to be incomputable. We quantify its incomputability by placing various flavors of Solomonoff's prior M in the arithmetical hierarchy. We also derive computability bounds for knowledge-seeking agents, and give a limit-computable weakly asymptotically optimal reinforcement learning agent.Comment: ALT 201

Extreme State Aggregation Beyond MDPs

We consider a Reinforcement Learning setup where an agent interacts with an environment in observation-reward-action cycles without any (esp.\ MDP) assumptions on the environment. State aggregation and more generally feature reinforcement learning is concerned with mapping histories/raw-states to reduced/aggregated states. The idea behind both is that the resulting reduced process (approximately) forms a small stationary finite-state MDP, which can then be efficiently solved or learnt. We considerably generalize existing aggregation results by showing that even if the reduced process is not an MDP, the (q-)value functions and (optimal) policies of an associated MDP with same state-space size solve the original problem, as long as the solution can approximately be represented as a function of the reduced states. This implies an upper bound on the required state space size that holds uniformly for all RL problems. It may also explain why RL algorithms designed for MDPs sometimes perform well beyond MDPs.Comment: 28 LaTeX pages. 8 Theorem

Bayesian reinforcement learning with exploration

We consider a general reinforcement learning problem and show that carefully combining the Bayesian optimal policy and an exploring policy leads to minimax sample-complexity bounds in a very general class of (history-based) environments. We also prove lower bounds and show that the new algorithm displays adaptive behaviour when the environment is easier than worst-case

Prospectus, April 18, 1984

CHORAL UNION DEMANDING AND REWARDING; News Digest; Is your child part of the identi-child program?; Budding playwrights get chance to have work produced; PC Happenings: Parkland wins Automotive Contest, German Club annual Springfest, EMT workshop offered, Petitions available for Stu-Go, Stu-Go lacks quorum; Here Comes the Easter Bunny (or the Easter Hare?); Faces We Make; Former Prospectus entertainment writer: Alender services held; Strange things at the library; Only Food Service Management course in area: Sutton leads Food Service Management program; Criminal justice program well rounded; Running may increase protein need; Easter means Easter egg time; Second Wind hosts race; Did You Know...; Classifieds; Creative Corner...Especially for you!!: Recollections, She\u27s More than a Nurse, You are a corn-fed steak..., Memories..., A fire burns, AKTING??????????????..., Sometimes in their heed to tact..., Clouds, Disturb Not the Dead, Follow the Wind, I don\u27t know why I bother..., Innoncent Eyes, Please tell me what it is you want..., Running scared from yourself and tripped, babe..., Time Bomb, Don\u27t go away--Linger on..., Class, Raggedy Ann lay in the back of an old station wagon..., Too Late, To God; Ice Capades comes to town: Skaters say it\u27s hard work but well worth it; few surprises during Hollywood\u27s biggest night; \u27Queen\u27 film at Assembly Hall; Director shines in film; \u27Go-Go\u27s\u27 are back on track; \u27Weird Al\u27 hits big time; Fan Club to host film; Parkland College 1984 baseball roster; Cobra men lose two; 1984 Parkland Outdoor Track Bests; Sports Digest; Women lose twin bill; Prospectus survey resultshttps://spark.parkland.edu/prospectus_1984/1024/thumbnail.jp

Neuroscience in gambling policy and treatment: an interdisciplinary perspective

Neuroscientific explanations of gambling disorder can help people make sense of their experiences and guide the development of psychosocial interventions. However, the societal perceptions and implications of these explanations are not always clear or helpful. Two workshops in 2013 and 2014 brought together multidisciplinary researchers aiming to improve the clinical and policy-related effects of neuroscience research on gambling. The workshops revealed that neuroscience can be used to improve identification of the dangers of products used in gambling. Additionally, there was optimism associated with the diagnostic and prognostic uses of neuroscience in problem gambling and the provision of novel tools (eg, virtual reality) to assess the effectiveness of new policy interventions before their implementation. Other messages from these workshops were that neuroscientific models of decision making could provide a strong rationale for precommitment strategies and that interdisciplinary collaborations are needed to reduce the harms of gambling

Personalization Paradox in Behavior Change Apps:Lessons from a Social Comparison-Based Personalized App for Physical Activity

Social comparison-based features are widely used in social computing apps. However, most existing apps are not grounded in social comparison theories and do not consider individual differences in social comparison preferences and reactions. This paper is among the first to automatically personalize social comparison targets. In the context of an m-health app for physical activity, we use artificial intelligence (AI) techniques of multi-armed bandits. Results from our user study (n=53) indicate that there is some evidence that motivation can be increased using the AI-based personalization of social comparison. The detected effects achieved small-to-moderate effect sizes, illustrating the real-world implications of the intervention for enhancing motivation and physical activity. In addition to design implications for social comparison features in social apps, this paper identified the personalization paradox, the conflict between user modeling and adaptation, as a key design challenge of personalized applications for behavior change. Additionally, we propose research directions to mitigate this Personalization Paradox

TranscriptomeBrowser: A Powerful and Flexible Toolbox to Explore Productively the Transcriptional Landscape of the Gene Expression Omnibus Database

International audienceAs public microarray repositories are constantly growing, we are facing the challenge of designing strategies to provide productive access to the available data.\ We used a modified version of the Markov clustering algorithm to systematically extract clusters of co-regulated genes from hundreds of microarray datasets stored in the Gene Expression Omnibus database (n = 1,484). This approach led to the definition of 18,250 transcriptional signatures (TS) that were tested for functional enrichment using the DAVID knowledgebase. Over-representation of functional terms was found in a large proportion of these TS (84%). We developed a JAVA application, TBrowser that comes with an open plug-in architecture and whose interface implements a highly sophisticated search engine supporting several Boolean operators (http://tagc.univ-mrs.fr/tbrowser/). User can search and analyze TS containing a list of identifiers (gene symbols or AffyIDs) or associated with a set of functional terms.\ As proof of principle, TBrowser was used to define breast cancer cell specific genes and to detect chromosomal abnormalities in tumors. Finally, taking advantage of our large collection of transcriptional signatures, we constructed a comprehensive map that summarizes gene-gene co-regulations observed through all the experiments performed on HGU133A Affymetrix platform. We provide evidences that this map can extend our knowledge of cellular signaling pathways

Corporate images and customer behavioral intentions in an environmentally certified context: Promoting environmental sustainability in the hospitality industry

Growing environmental awareness has made customers change their attitudes andincreasingly demand that the hospitality industry provides products and services thatare environmentally friendly. This sector faces increasing pressure to operate in amore ecofriendly manner given its negative influence on the natural environment.Extant research demonstrates that sustainable tourism can be promoted throughenvironmental certifications. However, little attention has been paid to the relevanceof customer perceptions about these schemes and their influence on customerbehavioral intentions. So that, this study attempts to explore the conditions underwhich perceived green image leads to favorable customer behavioral intentionstowards environmentally certified hotels by considering the mediating effects offunctional and emotional images. A structured questionnaire was used to collect datafrom hotel customers in Spain. The results indicate that green image serves as apredictor of functional image, which in turn is linked to customer behavioralintentions. This shows that the evaluation of environmental issues influences theassessment of cognitive aspects, although not the direct evaluation of affectiveaspects. Consequently, green image associations directly influence the cognitiveresponses of consumers but not their emotions. Therefore, consumers will evaluatea hotel's functional image not only by considering traditional attributes but also bytaking into account environmental issues. These findings suggest that hotelcompanies should work to develop a green positioning strategy developing productsand services possessing both greenness and high?value attributes

The mothers, Omega-3 and mental health study

<p>Abstract</p> <p>Background</p> <p>Major depressive disorder (MDD) during pregnancy and postpartum depression are associated with significant maternal and neonatal morbidity. While antidepressants are readily used in pregnancy, studies have raised concerns regarding neurobehavioral outcomes in exposed infants. Omega-3 fatty acid supplementation, most frequently from fish oil, has emerged as a possible treatment or prevention strategy for MDD in non-pregnant individuals, and may have beneficial effects in pregnant women. Although published observational studies in the psychiatric literature suggest that maternal docosahexaenoic acid (DHA) deficiency may lead to the development of MDD in pregnancy and postpartum, there are more intervention trials suggesting clinical benefit for supplementation with eicosapentaenoic acid (EPA) in MDD.</p> <p>Methods/Design</p> <p>The Mothers, Omega-3 and Mental Health study is a double blind, placebo-controlled, randomized controlled trial to assess whether omega-3 fatty acid supplementation may prevent antenatal and postpartum depressive symptoms among pregnant women at risk for depression. We plan to recruit 126 pregnant women at less than 20 weeks gestation from prenatal clinics at two health systems in Ann Arbor, Michigan and the surrounding communities. We will follow them prospectively over the course of their pregnancies and up to 6 weeks postpartum. Enrolled participants will be randomized to one of three groups: a) EPA-rich fish oil supplement (1060 mg EPA plus 274 mg DHA) b) DHA-rich fish oil supplement (900 mg DHA plus 180 mg EPA; or c) a placebo. The primary outcome for this study is the Beck Depression Inventory (BDI) score at 6 weeks postpartum. We will need to randomize 126 women to have 80% power to detect a 50% reduction in participants' mean BDI scores with EPA or DHA supplementation compared with placebo. We will also gather information on secondary outcome measures which will include: omega-3 fatty acid concentrations in maternal plasma and cord blood, pro-inflammatory cytokine levels (IL-1β, IL-6, and TNF-α) in maternal and cord blood, need for and dosage of antidepressant medications, and obstetrical outcomes. Analyses will be by intent to treat.</p> <p>Discussion</p> <p>This study compares the relative effectiveness of DHA and EPA at preventing depressive symptoms among pregnant women at risk.</p> <p>Trial registration</p> <p>Clinical trial registration number: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00981877">NCT00711971</a></p

Re-Arrest Among Juvenile Justice-Involved Youth: An Examination Of The Static And Dynamic Risk Factors

The purpose of this study is to investigate the static and dynamic risk factors for re-arrest among detained youth by examining gender, race/ethnicity, age, special education and mental health variables (i.e., anger/irritability, depression/anxiety, somatic complaints, suicide ideation, thought disturbances, and traumatic experiences). The demographic profiles of detained youth with one admit were also compared with those with multiple admits to the juvenile detention center. With regards to static risk factors, older, white, and special education were significantly at risk of re-arrest. Concerning dynamic risk factors, only anger/irritability predicted re-arrest. Practice implications are also discussed