Church's Problem Revisited

1999 ◽  
Vol 5 (2) ◽  
pp. 245-263 ◽  
Author(s):  
Orna Kupferman ◽  
Moshe Y. Vardi
Keyword(s):  
Incomplete Information ◽  
Program Synthesis ◽  
Synthesis Problem ◽  
Tree Automata ◽  
Full Generality ◽  
Input Signals ◽  
Alternating Tree Automata ◽  
History Of ◽  
Underlying Processes

AbstractIn program synthesis, we transform a specification into a system that is guaranteed to satisfy the specification. When the system is open, then at each moment it reads input signals and writes output signals, which depend on the input signals and the history of the computation so far. The specification considers all possible input sequences. Thus, if the specification is linear, it should hold in every computation generated by the interaction, and if the specification is branching, it should hold in the tree that embodies all possible input sequences.Often, the system cannot read all the input signals generated by its environment. For example, in a distributed setting, it might be that each process can read input signals of only part of the underlying processes. Then, we should transform a specification into a system whose output depends only on the readable parts of the input signals and the history of the computation. This is called synthesis with incomplete information. In this work we solve the problem of synthesis with incomplete information in its full generality. We consider linear and branching settings with complete and incomplete information. We claim that alternation is a suitable and helpful mechanism for coping with incomplete information. Using alternating tree automata, we show that incomplete information does not make the synthesis problem more complex, in both the linear and the branching paradigm. In particular, we prove that independently of the presence of incomplete information, the synthesis problems for CTL and CTL*. are complete for EXPTIME and 2EXPTIME, respectively.

The Holocene Occupations of Southern Belize

2020 ◽  
pp. 16-38 ◽  
Author(s):  
Keith M. Prufer ◽  
Douglas J. Kennett
Keyword(s):  
Climate Reconstruction ◽  
Archaeological Research ◽  
Human Occupation ◽  
The Holocene ◽  
Social Pressures ◽  
History Of ◽  
Underlying Processes

In Chapter 2, Keith Prufer and Douglas J. Kennett focus on the long history of human occupation in southern Belize, from initial colonization at the end of the Pleistocene to the present. First occupied by Paleoindians, the landscape of southern Belize has seen 10 millennia of cultural modifications. The authors, drawing on more than two decades of archaeological research, discuss why studying the long historical trajectories of settlements within a region can provide data about how humans adapt and reorganize over long periods of time and insights into underlying processes of resilience and reorganization in response to climatic, demographic, and social pressures. The chapter draws on climate reconstruction data to look at Holocene adaptations to a changing landscape.

scholarly journals Remote Sensing of Boreal Wetlands 1: Data Use for Policy and Management

2020 ◽  
Vol 12 (8) ◽  
pp. 1320 ◽  
Author(s):  
Laura Chasmer ◽  
Danielle Cobbaert ◽  
Craig Mahoney ◽  
Koreen Millard ◽  
Daniel Peters ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Remotely Sensed ◽  
Decision Makers ◽  
Remotely Sensed Data ◽  
Ramsar Convention ◽  
Canadian Perspective ◽  
History Of ◽  
Wetland Inventory ◽  
Monitoring And Measurement ◽  
Underlying Processes

Wetlands have and continue to undergo rapid environmental and anthropogenic modification and change to their extent, condition, and therefore, ecosystem services. In this first part of a two-part review, we provide decision-makers with an overview on the use of remote sensing technologies for the ‘wise use of wetlands’, following Ramsar Convention protocols. The objectives of this review are to provide: (1) a synthesis of the history of remote sensing of wetlands, (2) a feasibility study to quantify the accuracy of remotely sensed data products when compared with field data based on 286 comparisons found in the literature from 209 articles, (3) recommendations for best approaches based on case studies, and (4) a decision tree to assist users and policymakers at numerous governmental levels and industrial agencies to identify optimal remote sensing approaches based on needs, feasibility, and cost. We argue that in order for remote sensing approaches to be adopted by wetland scientists, land-use managers, and policymakers, there is a need for greater understanding of the use of remote sensing for wetland inventory, condition, and underlying processes at scales relevant for management and policy decisions. The literature review focuses on boreal wetlands primarily from a Canadian perspective, but the results are broadly applicable to policymakers and wetland scientists globally, providing knowledge on how to best incorporate remotely sensed data into their monitoring and measurement procedures. This is the first review quantifying the accuracy and feasibility of remotely sensed data and data combinations needed for monitoring and assessment. These include, baseline classification for wetland inventory, monitoring through time, and prediction of ecosystem processes from individual wetlands to a national scale.

scholarly journals The generalized perpetual American exchange-option problem

2008 ◽  
Vol 40 (1) ◽  
pp. 163-182 ◽  
Author(s):  
Shek-Keung Tony Wong
Keyword(s):  
Optimal Stopping ◽  
First Passage Time ◽  
Passage Time ◽  
Optimal Stopping Problem ◽  
Full Generality ◽  
Investment Timing ◽  
Current Context ◽  
Geometric Brownian Motions ◽  
Underlying Processes

This paper revisits a general optimal stopping problem that often appears as a special case in some finance applications. The problem is essentially of the same form as the investment-timing problem of McDonald and Siegel (1986) in which the underlying processes are two correlated geometric Brownian motions (GBMs) with drifts less than the discount rate. By contrast, we attempt to analyze the underlying optimal stopping problem to its full generality without imposing any restriction on the drifts of the GBMs. By extending the first passage time approach of Xia and Zhou (2007) to the current context, we manage to obtain a complete and explicit characterization of the solution to the problem on all possible drift domains. Our analysis leads to a new and interesting observation that the underlying optimal stopping problem admits a two-sided optimal continuation region on some certain parameter domains.

scholarly journals Adapting to extremes: reconstructing niche evolution in Australian Acacia over time and space

2021 ◽  
Author(s):  
Xia Hua ◽  
Marcel Cardillo ◽  
Lindell Bromham
Keyword(s):  
Phylogenetic Reconstruction ◽  
Environmental Niche ◽  
Niche Evolution ◽  
Spatial And Temporal Patterns ◽  
Niche Modelling ◽  
Statistical Framework ◽  
Phylogenetic Studies ◽  
History Of ◽  
Key Aspects ◽  
Underlying Processes

Macroevolutionary analysis is increasingly being used to study biodiversity responses to climate change, for example by using phylogenetic node ages to infer periods of diversification, or phylogenetic reconstruction of traits to infer adaptation to particular stresses. Here we apply a new macroevolutionary method to investigate the responses of a diverse plant genus, Acacia, to increasing aridity and salinity in Australia from the Miocene to the present. The Niche Evolution Model (NEMo) combines environmental niche modelling with phylogenetic comparative methods in a single statistical framework, to estimate current environmental tolerances, reconstruct the history of niche evolution and infer rates of change in key aspects of environmental tolerance. Using a large database of Acacia occurrence records and presence-absence survey sites, we find that both spatial and temporal patterns in niche evolution of Acacia are consistent with the aridification history of Australia and suggest high niche lability along both axes, which has allowed Acacia to quickly exploit new niches created during the aridification of the continent, and resulting in their current dominance of many habitats across Australia. This study demonstrates that phylogenetic studies of niche evolution can move beyond application of simple trait-based models, allowing the underlying processes of speciation, adaptation and dispersal to be explicitly modelled in a macroecological and macroevolutionary context.

scholarly journals The Concept of the Pictography as a Background for «Free Hands» Written by Paul Eluard and Man Ray

2020 ◽  
Vol 12 (2) ◽  
pp. 22-28
Author(s):  
Yuliia Ivlieva
Keyword(s):  
Semantic Analysis ◽  
Visual Metaphors ◽  
Sign Systems ◽  
Hands On ◽  
Poetic Text ◽  
Man Ray ◽  
History Of ◽  
Paul Eluard ◽  
Basic Features ◽  
Underlying Processes

This article is part of a deeper study of the phenomenon of "picto-poetry" on the example of Paul Eluard and Man Ray's collection "Free Hands". The article proves the intermediality hypothesis of a collection based on the history of its creation, where the two types of arts not only complement each other, but merge into one, creating new forms and genres of French poetry. The purpose of the study is to determine the nature and imagery of the interaction of visual and verbal codes of artistic reality in the collection "Free Hands", as well as to identify the basic features of the composition " in four hands" on the example of the frontispiece of the collection. Research methods: descriptive, structural and semantic analysis methods that allow the identification of relationships between different sign systems (visual, plastic, etc.). The main feature of Paul Eluard and Man Ray's picto-poetic collection "Free Hands", in the preface to which P. Eluard outlined the principles of a single picto-poetic reproduction of the world, is the special principle of organizing the artistic space, when graphic realities also become "literary text", and the poetic text and its graphic "second voice" cannot be interpreted separately. The multi-layered and heterogeneous internal connections in the texts and graphics of authors serve as a form of reproduction of the underlying processes that take place in the human psyche, and the texts of Eluard create visual metaphors that resemble dreams.

scholarly journals Emergency Care APP – Analysis and Review

2021 ◽  
pp. 276-278
Author(s):  
Prajakta Markad ◽  
Satyam Takawale ◽  
Nikhil Lomate ◽  
Prof. Aparna Mote
Keyword(s):  
Incomplete Information ◽  
Emergency Care ◽  
Correct Diagnosis ◽  
Time Frame ◽  
The World ◽  
Main Motive ◽  
History Of ◽  
Doctors And Nurses

Life has changed a lot after the world was struck by the pandemic. People have to think twice before touching their loved ones. The most affected relationship, as we observed, is that between a doctor and a patient. People are afraid of going to the hospital as they fear contracting COVID-19 from another patient or the doctors and nurses that will be checking them. The root of this fear is Touch. Patients are afraid of contracting the virus and thus prefer to either ignore their symptoms and go on with their day or lie to the doctors to get out of the hospital quickly. Incomplete information about the symptoms may lead misdiagnosis, which can be fatal. Our main motive to implement this application is to bridge the gap created by the pandemic between doctors and patients. This app will help a person to catalog their symptoms, keep a tab of their medication and if required, call for help from the nearest hospital. This will ensure that all the symptoms are catalogued, the history of the patient is already known, which ensures correct diagnosis in a shorter time frame with relatively minimum contact. The proposed app also has a feature to specify whether the person using the application is specially abled. This feature will ensure that the person is cared for in a way that suits their needs.

Goal Attainment

2019 ◽  
pp. 245-268
Author(s):  
Peter M. Gollwitzer ◽  
Gabriele Oettingen
Keyword(s):  
Goal Attainment ◽  
Intervention Studies ◽  
Implementation Intentions ◽  
Self Regulation ◽  
Goal Pursuit ◽  
The Self ◽  
Mental Contrasting ◽  
History Of ◽  
Regulation Strategies ◽  
Underlying Processes

This chapter begins with a description of how the goal concept emerged in the history of the psychology of motivation to better understand the important role it plays in current research on motivation. The chapter then turns to the self-regulation of goal pursuit. The effects and underlying processes of two different self-regulation strategies will be discussed in detail: mental contrasting and forming implementation intentions. The chapter concludes with a report of the results of recent intervention studies that combine the self-regulation strategies of mental contrasting and forming implementation intentions to help people enhance goal attainment in the health, academic, and interpersonal domains.

scholarly journals Abnormal development of cerebellar-striatal circuitry in Huntington disease

Neurology ◽  
2020 ◽  
Vol 94 (18) ◽  
pp. e1908-e1915 ◽  
Author(s):  
Alexander V. Tereshchenko ◽  
Jordan L. Schultz ◽  
Joel E. Bruss ◽  
Vincent A. Magnotta ◽  
Eric A. Epping ◽  
...  
Keyword(s):  
Functional Mri ◽  
Huntington Disease ◽  
Developmental Trajectories ◽  
Abnormal Development ◽  
Compensatory Mechanisms ◽  
Functional Connections ◽  
Input Signals ◽  
History Of ◽  
Age Range ◽  
Over Time

ObjectiveTo test the hypothesis that the trajectory of functional connections over time of the striatum and the cerebellum differs between presymptomatic patients with the Huntington disease (HD) gene expansion (GE) and patients with a family history of HD but without the GE (GNE), we evaluated functional MRI data from the Kids-HD study.MethodsWe utilized resting-state, functional MRI data from participants in the Kids-HD study between 6 and 18 years old. Participants were divided into GE (CAG 36–59) and GNE (CAG <36) groups. Seed-to-seed correlations were calculated among 4 regions that provide input signals to the anterior cerebellum: (1) dorsocaudal putamen, (2) globus pallidus externa, (3) subthalamic nucleus, and (4) pontine nuclei; and 2 regions that represented output from the cerebellum: the dentate nucleus to the (1) ventrolateral thalamus and (2) dorsocaudal putamen. Linear mixed effects regression models evaluated differences in developmental trajectories of these connections over time between groups.ResultsFour of the six striatal–cerebellum correlations showed significantly different trajectories between groups. All showed a pattern where in the early age ranges (6–12 years) there was hyperconnectivity in the GE compared to the GNE, with those trajectories showing linear decline in the latter half of the age range.ConclusionThese results parallel previous findings showing striatal hypertrophy in children with GE as early as age 6. These findings support the notion of developmentally higher connectivity between the striatum and cerebellum early in the life of the child with HD GE, possibly setting the stage for cerebellar compensatory mechanisms.

Alternating tree automata

1983 ◽  
pp. 392-404 ◽  
Author(s):  
Giora Slutzki
Keyword(s):  
Tree Automata ◽  
Alternating Tree Automata
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