scholarly journals Structure and Complexity in Planning with Unary Operators

2003 ◽  
Vol 18 ◽  
pp. 315-349 ◽  
Author(s):  
R. I. Brafman ◽  
C. Domshlak
Keyword(s):  
Planning Problem ◽  
Natural Structure ◽  
Causal Graph ◽  
Plan Generation ◽  
Positive Side ◽  
Unary Operator ◽  
Causal Graphs ◽  
Single Effect ◽  
The Relationship ◽  
Comprehensive Study

Unary operator domains -- i.e., domains in which operators have a single effect -- arise naturally in many control problems. In its most general form, the problem of STRIPS planning in unary operator domains is known to be as hard as the general STRIPS planning problem -- both are PSPACE-complete. However, unary operator domains induce a natural structure, called the domain's causal graph. This graph relates between the preconditions and effect of each domain operator. Causal graphs were exploited by Williams and Nayak in order to analyze plan generation for one of the controllers in NASA's Deep-Space One spacecraft. There, they utilized the fact that when this graph is acyclic, a serialization ordering over any subgoal can be obtained quickly. In this paper we conduct a comprehensive study of the relationship between the structure of a domain's causal graph and the complexity of planning in this domain. On the positive side, we show that a non-trivial polynomial time plan generation algorithm exists for domains whose causal graph induces a polytree with a constant bound on its node indegree. On the negative side, we show that even plan existence is hard when the graph is a directed-path singly connected DAG. More generally, we show that the number of paths in the causal graph is closely related to the complexity of planning in the associated domain. Finally we relate our results to the question of complexity of planning with serializable subgoals.

scholarly journals A case study and proposal for publishing directed acyclic graphs: The effectiveness of the quadrivalent HPV vaccine in perinatally HIV exposed girls

2021 ◽  
Author(s):  
Ruby Barnard-Mayers ◽  
Hiba Kouser ◽  
Jamie A. Cohen ◽  
Katherine Tassiopoulos ◽  
Ellen C. Caniglia ◽  
...  
Keyword(s):  
Hpv Vaccine ◽  
Directed Acyclic Graphs ◽  
Hiv Status ◽  
Causal Graph ◽  
Acyclic Graphs ◽  
Causal Graphs ◽  
Hiv Exposed ◽  
Living With Hiv ◽  
The Relationship

Background: Developing a causal graph is an important step in etiologic research planning and can be used to highlight data flaws and irreparable bias and confounding. Recent findings have suggested that the human papillomavirus (HPV) vaccine is less effective in protection against HPV associated disease in a population of girls living with HIV. Development: In order to understand the relationship between HIV status and HPV vaccine effectiveness, it is important to outline the key assumptions of the causal mechanisms before designing a study to investigate the effect of the HPV vaccine in girls living with HIV infection. Application: We present a causal graph to describe our assumptions and proposed approach to explore this relationship. We hope to obtain feedback on our assumptions prior to data analysis and exemplify the process for designing an etiologic study.Conclusion: The approach we lay out in this paper may be useful for other researchers who have an interest in using causal graphs to describe and assess assumptions in their own research prior to undergoing data collection and/or analysis.

scholarly journals The Complexity of Planning Problems With Simple Causal Graphs

2008 ◽  
Vol 31 ◽  
pp. 319-351 ◽  
Author(s):  
O. Gimenez ◽  
A. Jonsson
Keyword(s):  
Polynomial Time Algorithm ◽  
Time Algorithm ◽  
Planning Problem ◽  
State Variables ◽  
Plan Generation ◽  
Binary State ◽  
Causal Graphs ◽  
Np Complete ◽  
Binary State Variables ◽  
Planning Problems

We present three new complexity results for classes of planning problems with simple causal graphs. First, we describe a polynomial-time algorithm that uses macros to generate plans for the class 3S of planning problems with binary state variables and acyclic causal graphs. This implies that plan generation may be tractable even when a planning problem has an exponentially long minimal solution. We also prove that the problem of plan existence for planning problems with multi-valued variables and chain causal graphs is NP-hard. Finally, we show that plan existence for planning problems with binary state variables and polytree causal graphs is NP-complete.

scholarly journals Conversion of land use and household livelihoods in Vietnam: A study in Nghe An

2021 ◽  
Vol 6 (1) ◽  
pp. 82-92
Author(s):  
Tran Tuan Nguyen
Keyword(s):  
Quality Of Life ◽  
Land Use ◽  
Industrial Park ◽  
Average Income ◽  
Positive Side ◽  
Current Period ◽  
Improper Use ◽  
The Relationship ◽  
Double Impact

Abstract This article describes the relationship between the land use purpose conversion and households’ livelihoods in suburban Vinh City, Nghe An province. In the survey with 170 households losing their land to build the VSIP Nghe An industrial park project, this article shows the double impact of this issue. (1) On the positive side, households’ quality of life in the current period shows a significant improvement. They are living in better conditions with more spacious houses and modern facilities than before. The average income of households increased by 900 USD than before. (2) On the negative side, the unemployment rate increases with women older than 35 years and men older than 40 years. Along with the improper use of compensation received, income sustainability is a doubt for these households’ future.

Material Properties and Design Aspects of Folding Bicycle Frame

2011 ◽  
Vol 264-265 ◽  
pp. 777-782 ◽  
Author(s):  
M.A. Maleque ◽  
M.S. Hossain ◽  
S. Dyuti
Keyword(s):  
Material Properties ◽  
Raw Material ◽  
New Materials ◽  
Materials Properties ◽  
Advantages And Disadvantages ◽  
Bicycle Frame ◽  
Successful Design ◽  
Future Direction ◽  
The Relationship ◽  
Comprehensive Study

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.

Automatic Planning of Smooth Trajectories for Pick-and-Place Operations

1991 ◽  
Author(s):  
Clément M. Gosselin ◽  
Ammar Hadj-Messaoud
Keyword(s):  
Joint Space ◽  
Inverse Kinematic ◽  
Planning Problem ◽  
Inverse Kinematic Problem ◽  
Polynomial Solutions ◽  
Joint Coordinates ◽  
Pick And Place ◽  
Lift Off ◽  
The Relationship ◽  
Third Derivative

Abstract This paper proposes some new polynomial solutions to the trajectory planning problem encountered in pick-and-place operations. When a robotic manipulator is used for such operations, it is possible to plan the required trajectory in joint space, provided that the inverse kinematic problem has been solved for the initial and final configurations — and possibly for a lift-off and a set-down configuration — and that the workspace is free of obstacles. Polynomial solutions to this problem can be found in the literature. However, they usually provide continuity up to the second derivative only, leading to a discontinuous jerk. The solutions derived in this paper preserve the continuity of the third derivative of the joint coordinates, thereby ensuring smooth trajectories with smooth variations of the actuator currents. Moreover, whenever possible, unique polynomial expressions valid between the initial and final configurations are used in order to simplify the logic. Polynomial formulations without lift-off and set-down configurations are first presented. Then, these intermediate configurations are introduced, leading to a new set of solutions. A global algorithm is then discussed in order to clearly indicate the relationship between the different solutions. Finally, an example illustrating the application to a pick-and-place operation is solved.

Inequality Overhang: A Heterogeneous Approach

2019 ◽  
pp. 106-133
Author(s):  
Francesco Grigoli ◽  
Adrian Robles
Keyword(s):  
Economic Development ◽  
Income Inequality ◽  
Shock Absorber ◽  
Negative Impact ◽  
Empirical Literature ◽  
Debt Overhang ◽  
Positive Side ◽  
Low Levels ◽  
The Relationship ◽  
Income Concentration

The linearity of the relationship between income inequality and economic development has been long questioned. While theory provides arguments for which the shape of the relationship may be positive for low levels of inequality and negative for high ones, most of the empirical literature assumes a linear specification finding conflicting results. Employing an innovative empirical approach, robust to endogeneity, we find pervasive evidence of nonlinearities. In particular, similar to the debt-overhang literature, we identify an inequality-overhang level, in that the slope of the relationship between income inequality and economic development switches from positive to negative at a net Gini coefficient of about 27 per cent. We also find that in an environment characterized by widespread financial inclusion and high income concentration, rising income inequality has a larger negative impact on economic development because banks may curtail credit to customers at the lower end of the income distribution. On the positive side, a sufficiently high female labor participation can act as a shock absorber reducing such a negative impact, possibly through a more efficient allocation of resources.

scholarly journals On the Concept of Legal Education

2020 ◽  
Vol 15 (1) ◽  
pp. 179-188
Author(s):  
A. S. Dotsenko
Keyword(s):  
State Policy ◽  
Legal Education ◽  
Legal Culture ◽  
Legal Socialization ◽  
Legal Literature ◽  
Independent Direction ◽  
Education Act ◽  
Definition Of ◽  
The Relationship ◽  
Comprehensive Study

The paper attempts to conduct a comprehensive study of legal education as a legal category. Modern scientific approaches to the definition of the concept of legal education are considered, a distinction is made and the relationship between the legal phenomenon under study and related legal categories is determined. The author comes to the unequivocal conclusion that legal education as a legal category has an independent legal significance. Based on the analysis of modern scientific legal literature and current legislation, the author identifies features of legal education that clarify and supplement the existing concepts. Today, legal education is an independent direction of state policy. The measures implemented in the system of legal education act as a kind of tool for the formation of a legal culture and stimulate the active lawful behavior of individuals. The purpose of legal education is to ensure the full legal socialization of a person, and the final expected result is the formation of a high legal culture of society.

The value of philosophical analysis of history for ecological education

2021 ◽  
pp. 37-41
Author(s):  
N.V. Popkova ◽  
Keyword(s):  
Historical Analysis ◽  
Ecological Crisis ◽  
Negative Consequences ◽  
New Concepts ◽  
Historical Processes ◽  
Man And Nature ◽  
The Relationship ◽  
Evolutionary Role ◽  
Comprehensive Study

Discussed is the need for a historical analysis of the relationship between man and nature for the formation of the theoretical basis of environmental education is considered. It is shown that a holistic picture of the historical interaction between mankind and the Earth’s biosphere is necessary for understanding modern global processes: the disclosure of the causes of the ecological crisis will help to create programs for the greening of human activity. Traditional historical approaches developed by the philosophy of history are not suitable for solving this problem, since they do not take into account the natural limitations of technological progress and the evolutionary role of humanity in the biosphere. The article discusses new concepts proposed for a comprehensive study of historical processes and the biosphere transformations caused by them. It is concluded that the level of their development does not yet allow using them for educational purposes. Nevertheless, the analysis of the consequences of technical development made with their help in the context of historical reality makes it possible to reflect the trend of technologization of man and nature. The main regularities of the relationship between mankind and the biosphere can be distinguished on the basis of the ratio of biological and technological factors, on which the life of people depended in different eras. Understanding the nature of the modern ecological crisis is necessary for the development of scientifically grounded programs to neutralize the negative consequences of the formation and expansion of technical reality.

scholarly journals Die opkoms en huidige stand van die Nuwe-Testamentiese ondersoek in Suid-Afrika: Deel 3 - ’n Kritiese evaluasie

1994 ◽  
Vol 50 (3) ◽  
Author(s):  
A. B. Du Toit
Keyword(s):  
South African ◽  
New Testament ◽  
Critical Evaluation ◽  
Political Field ◽  
Faith And Reason ◽  
Positive Side ◽  
Current State ◽  
New Testament Studies ◽  
Pros And Cons ◽  
The Relationship

The rise and current state of New Testament research in South Africa: Part 3 - A critical evaluation First the pros and cons of the South African emphasis on methodology arw discussed. On the positive side a much greater sensitivity for methodological austerity has been developed. On the negative side New Testament research has not contributed enough towards serving theology and the church at large. In dealing with the problem of relevancy in the socio-political field, it is acknowledged that more should be done, without putting the specific character of New Testament studies in jeopardy. The burning issue of the relationship between faith and reason should be tackled. The correct approach seems to be respecting the tension between these two entities, while at the same time working and striving towards closing the gap between them.

The COVID-19 pandemic lockdown: a buzz of negativity with a silver lining of social connectedness

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anthony Amoah ◽  
Benjamin Amoah
Keyword(s):  
Design Methodology ◽  
Social Connectedness ◽  
Online Survey ◽  
Content Type ◽  
Positive Side ◽  
Regression Approach ◽  
Show Evidence ◽  
The Relationship ◽  
Econometric Technique ◽  
Silver Lining

PurposeLockdowns are generally characterised by financial depletion, loneliness, stress, depression, loss of jobs and businesses, among others. The effect of the recent lockdown in Ghana as a result of COVID-19 pandemic has not been different. The primary question this study seeks to answer is: are lockdowns only characterised by negativity, or could there be a positive side that has not yet been harnessed?Design/methodology/approachTo answer this question, the authors rely on a dataset of 879 observations obtained through an online survey administered from 25 April to 3 May 2020. Using a regression approach, the authors applied an ordered probit econometric technique with its associated predicted margins.FindingsThe authors show evidence that in the midst of the negativity surrounding the lockdown, social connectedness is evident, especially in relatively less busy cities. The authors recommend that instead of losing oneself through social isolation and loneliness during lockdowns, people should use lockdowns as an opportunity to build and exhibit social capital and harness the opportunities associated with it. The authors also recommend that during lockdowns, channels of social connectedness should be made easily accessible and cheaper through a well-targeted government subsidy programme for the poor.Originality/valueTo the best of the authors' knowledge, this is a novel study that provides the first empirical evidence on the relationship between coronavirus disease 2019 (COVID-19) pandemic lockdown and social connectedness.

Sign in / Sign up

Export Citation Format

Share Document