scholarly journals The Role of Macros in Tractable Planning

2009 ◽  
Vol 36 ◽  
pp. 471-511 ◽  
Author(s):  
A. Jonsson

This paper presents several new tractability results for planning based on macros. We describe an algorithm that optimally solves planning problems in a class that we call inverted tree reducible, and is provably tractable for several subclasses of this class. By using macros to store partial plans that recur frequently in the solution, the algorithm is polynomial in time and space even for exponentially long plans. We generalize the inverted tree reducible class in several ways and describe modifications of the algorithm to deal with these new classes. Theoretical results are validated in experiments.

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>


2020 ◽  
pp. 174387212098228
Author(s):  
Stephen Riley

Drawing upon Kant’s analysis of the role of intuitions in our orientation towards knowledge, this paper analyses four points of departure in thinking about dignity: self, other, time and space. Each reveals a core area of normative discourse – authenticity in the self, respect for the other, progress through time and authority as the government of space – along with related grounds of resistance to dignity. The paper concludes with a discussion of the methodological challenge presented by our different dignitarian intuitions, in particular the role of universality in testing and cohering our intuitions.


Econometrics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 26
Author(s):  
Jennifer L. Castle ◽  
Jurgen A. Doornik ◽  
David F. Hendry

We investigate forecasting in models that condition on variables for which future values are unknown. We consider the role of the significance level because it guides the binary decisions whether to include or exclude variables. The analysis is extended by allowing for a structural break, either in the first forecast period or just before. Theoretical results are derived for a three-variable static model, but generalized to include dynamics and many more variables in the simulation experiment. The results show that the trade-off for selecting variables in forecasting models in a stationary world, namely that variables should be retained if their noncentralities exceed unity, still applies in settings with structural breaks. This provides support for model selection at looser than conventional settings, albeit with many additional features explaining the forecast performance, and with the caveat that retaining irrelevant variables that are subject to location shifts can worsen forecast performance.


2021 ◽  
Vol 87 (3) ◽  
Author(s):  
Joseph Olson ◽  
Jan Egedal ◽  
Michael Clark ◽  
Douglass A. Endrizzi ◽  
Samuel Greess ◽  
...  

Magnetic reconnection is explored on the Terrestrial Reconnection Experiment (TREX) for asymmetric inflow conditions and in a configuration where the absolute rate of reconnection is set by an external drive. Magnetic pileup enhances the upstream magnetic field of the high-density inflow, leading to an increased upstream Alfvén speed and helping to lower the normalized reconnection rate to values expected from theoretical consideration. In addition, a shock interface between the far upstream supersonic plasma inflow and the region of magnetic flux pileup is observed, important to the overall force balance of the system, thereby demonstrating the role of shock formation for configurations including a supersonically driven inflow. Despite the specialized geometry where a strong reconnection drive is applied from only one side of the reconnection layer, previous numerical and theoretical results remain robust and are shown to accurately predict the normalized rate of reconnection for the range of system sizes considered. This experimental rate of reconnection is dependent on system size, reaching values as high as 0.8 at the smallest normalized system size applied.


2019 ◽  
pp. 28-30
Author(s):  
Galina Aleksandrovna Sokolova

The article deals with the connection of time and space in literary text. It gives some definitions of the time-space concept, the chronotope; it presents different points of view of Russian linguists about the leading role of the chronotope components; it also lists the main ways of detecting the chronotope in literary work; it defines some features and characteristics of time and space in the chronotope.


Author(s):  
Iryna Prylipko

The paper considers the demonstrative aspects of intertext in the prose by Valerii Shevchuk and focuses on the peculiarities of the works’ interaction with the Bible, mythology, and literature, which takes place at the level of different forms and types of intertext. Particular attention is paid to revealing the specifc ‘dialogue’ of V. Shevchuk’s works with their pretexts — hagiography, autobiographical and diary’s literature of Baroque. ɒ e examples discussed testify to the depth and ramifications of the intertextual dialogue in the writer’s prose, reveal the intellectual, philosophical, and elitist nature of his texts. A dialogue with the Bible, mythology, world and Ukrainian literature in the works by V. Shevchuk unfolds in the form of open and hidden quotations, allusions, reminiscences. These details aim at deepening the representation of ideas and themes, forming the subtexts, interpreting images. The writer creates a new artistic form — metatext — mainly through the reinterpretation of the pretexts, among which the works of the Baroque period (poetic, autobiographical, diary genres) and hagiography dominate. Transforming the pretexts at the level of contents, plot, genre, time and space, narrative, V. Shevchuk expands them with monologues, dialogues, descriptions, and details. In the process of interpreting prototexts, the writer resorts to modeling original images, in the context of which he actualizes some worldview points, reveals important moral, ethical, and philosophical problems. Allowing the perception of his work as a ‘textual game’, the writer, at the same time, does not reduce the role of intertext to the level of intellectual play. Intertext becomes a peculiar way of continuing the literary discourses of the past in a dialogue with them. They become re-read, ‘supplemented’ and thus brought once again into the continuous process of forming culture.


2021 ◽  
Vol 1 (2) ◽  
pp. 80-87
Author(s):  
Toji Omonovich Norov ◽  

The universe, the space that make up their basis planets in it, their creation, the main essence of their creation, form, composition, meaning, movements, interactions, their influence on human life and activities, the role of man in the universe and in life on Earth, life, the criteria of activity and processes occurring in time and space have long been of interest to humanity. One of the main problems in the history of philosophy is the question of space and time. This problem was defined in different ways in the great schools of thought by thinkers of different periods. One of these great thinkers is Alisher Navoi. Navoi's works, along with other socio-philosophical themes, uniquely express and analyze the problems of the firmament and time. Its main feature is that it is based on the divine (pantheistic) religion, Islam, its holy book, the Koran and other theological sources, as well as on the secrets of nature and the Universe, the main miracle of Allah - human intelligence, the power of enlightenment, they are the key revealing all these secrets.


2021 ◽  
Vol 76 (2) ◽  
pp. 80-88
Author(s):  
Sh.A. Tazhibaeva ◽  
◽  
A. Zhienbayeva ◽  

The chronotope issue has been relevant in literary criticism for several decades. Furthermore, Plato argued that the essence of art is an imitation of real life. Aristotle pointed out that art creates its own world as something possible or probable and thereby reveals the essential properties of the real world. This article attempts to summarize the main research results on the problem of spatial images and the chronotope as a whole and thereby determine what is the specificity of the image of space, what is its role in a particular work. The purpose of the study is to establish the role of the chronotope in the recreation of the artistic image of Kazakhstan. In modern prose, chronotopic parameters are traced, the topography and symbolism of urban space are examined and its essential characteristics are given. In our opinion, the chronotope is an important modeling tool of literature. The appeal to this problem is due to the fact that the organization of the chronotope in the modern literature of Kazakhstan has become much more complicated in comparison with the traditional space-time paradigms. Anel Meken and Anastasia Skripnikova demonstrate their virtuoso «play with time and space». Time and space set the parameters of the artistic world of the work. Their relationship in prose reflects the structure of the author's consciousness, their worldview, and the system of philosophical ideas and, therefore, their interpretation is a search for means of expressing the author's idea. The study of the categories of time and space allows one to penetrate deeper into the «fabric» of a work of art, to reveal the specifics of its construction, to determine the concept of the writer's world. However, despite such different positions of researchers, controversy continues to this day in literary criticism.


Author(s):  
Brandy Daniels

This chapter explores how the aims of feminist theological projects are (or are not) sought/accomplished through their methodologies, turning to futurity as a rubric and Sarah Coakley’s théologie totale as a case study. This chapter argues that despite her laudable desire to reframe systematics under a formational frame that she sees as liberative, the teleological thrust and attendant onto-epistemological assumptions undergirding théologie totale (and the role of contemplation within it) betray and thwart precisely what her approach seeks to engender—the inculcation of un-mastery, attentiveness to otherness, and awareness of the complex interrelatedness of sexual and spiritual desires. In assuming and proffering a narratively-cohering and linear account of subjectivity that takes as given a clear telos of desire, Coakley’s methodology adheres to what José Esteban Muñoz calls “straight time’s choke hold.” The latter half of this chapter suggests that a feminist theological imagination (and method) that aligns with the aims of théologie totale approaches “the future” not by asking “how do we secure or obtain it?” but rather, “who are the ‘we’ that make up and enact it?” This chapter concludes by proposing potential hallmarks of a feminist theological method in a queer time and space.


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