Heuristics for Domain-Independent Planning: A Survey

2011 ◽  
Vol 135-136 ◽  
pp. 573-577 ◽  
Author(s):  
Rui Shi Liang ◽  
Min Huang

Increasing interest has been devoted to Planning as Heuristic Search over the years. Intense research has focused on deriving fast and accurate heuristics for domain-independent planning. This paper reports on an extensive survey and analysis of research work related to heuristic derivation techniques for state space search. Survey results reveal that heuristic techniques have been extensively applied in many efficient planners and result in impressive performances. We extend the survey analysis to suggest promising avenues for future research in heuristic derivation and heuristic search techniques.

Sadhana ◽  
1996 ◽  
Vol 21 (3) ◽  
pp. 263-290
Author(s):  
Pallab Dasgupta ◽  
P P Chakrabarti ◽  
S C Desarkar

2001 ◽  
Vol 14 ◽  
pp. 253-302 ◽  
Author(s):  
J. Hoffmann ◽  
B. Nebel

We describe and evaluate the algorithmic techniques that are used in the FF planning system. Like the HSP system, FF relies on forward state space search, using a heuristic that estimates goal distances by ignoring delete lists. Unlike HSP's heuristic, our method does not assume facts to be independent. We introduce a novel search strategy that combines hill-climbing with systematic search, and we show how other powerful heuristic information can be extracted and used to prune the search space. FF was the most successful automatic planner at the recent AIPS-2000 planning competition. We review the results of the competition, give data for other benchmark domains, and investigate the reasons for the runtime performance of FF compared to HSP.


2020 ◽  
Vol 68 ◽  
pp. 691-752
Author(s):  
Enrico Scala ◽  
Patrik Haslum ◽  
Sylvie Thiébaux ◽  
Miquel Ramirez

This paper studies novel subgoaling relaxations for automated planning with propositional and numeric state variables. Subgoaling relaxations address one source of complexity of the planning problem: the requirement to satisfy conditions simultaneously. The core idea is to relax this requirement by recursively decomposing conditions into atomic subgoals that are considered in isolation. Such relaxations are typically used for pruning, or as the basis for computing admissible or inadmissible heuristic estimates to guide optimal or satis_cing heuristic search planners. In the last decade or so, the subgoaling principle has underpinned the design of an abundance of relaxation-based heuristics whose formulations have greatly extended the reach of classical planning. This paper extends subgoaling relaxations to support numeric state variables and numeric conditions. We provide both theoretical and practical results, with the aim of reaching a good trade-o_ between accuracy and computation costs within a heuristic state-space search planner. Our experimental results validate the theoretical assumptions, and indicate that subgoaling substantially improves on the state of the art in optimal and satisficing numeric planning via forward state-space search.


2006 ◽  
Vol 15 (03) ◽  
pp. 433-464 ◽  
Author(s):  
AMOL DATTATRAYA MALI ◽  
MINH TANG

Significant advances have occurred in heuristic search for planning in the last eleven years. Many of these planners use A*-style search. We report on five sound and complete domain-independent forward state-space STRIPS planners in this paper. The planners are AWA* (Adjusted Weighted A*), MAWA* (Modified AWA*), AWA*-AC (AWA* with action conflict-based adjustment), AWA*-PD (AWA* with deleted preconditions-based adjustment), and AWA*-AC-LE (AWA*-AC with lazy evaluation). AWA* is the first planner to use node-dependent weighting in A*. MAWA*, AWA*-AC, AWA*-PD, and AWA*-AC-LE use conditional two-phase heuristic evaluation. MAWA* applies node-dependent weighting to a subset of the nodes in the fringe, after the two-phase evaluation. One novel idea in AWA*-AC-LE is lazy heuristic evaluation which does not construct relaxed plans to compute heuristic values for all nodes. We report on an empirical comparison of AWA*, MAWA*, AWA*-AC, AWA*-PD, and AWA*-AC-LE with classical planners AltAlt, FF, HSP-2 and STAN 4. Our variants of A* outperform these planners on several problems. The empirical evaluation shows that heuristic search planning is significantly benefitted by node-dependent weighting, conditional two-phase heuristic evaluation and lazy evaluation. We report on the insights about inferior performance of our planners in some domains using the notion of waiting time. We discuss many other variants of A*, state-space planners and directions for future work.


2010 ◽  
Vol 26 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Nale Lehmann-Willenbrock ◽  
Simone Kauffeld

In research on trust in the organizational context, there is some agreement evolving that trust should be measured with respect to various foci. The Workplace Trust Survey (WTS) by Ferres (2002) provides reliable assessment of coworker, supervisor, and organizational trust. By means of a functionally equivalent translation, we developed a German version of the questionnaire (G-WTS) comprising 21 items. A total of 427 employees were surveyed with the G-WTS and questionnaires concerning several work-related attitudes and behaviors and 92 of these completed the survey twice. The hypothesized three-dimensional conceptualization of organizational trust was confirmed by confirmatory factor analysis. The G-WTS showed good internal consistency and retest reliability values. Concerning convergent validity, all of the three G-WTS dimensions positively predicted job satisfaction. In terms of discriminant validity, Coworker Trust enhanced group cohesion; Supervisor Trust fostered innovative behavior, while Organizational Trust was associated with affective commitment. Theoretical and practical contributions as well as opportunities for future research with the G-WTS are discussed.


Author(s):  
Pankaj Musyuni ◽  
Geeta Aggarwal ◽  
Manju Nagpal ◽  
Ramesh K. Goyal

Background: Protecting intellectual property rights are important and particularly pertinent for inventions which are an outcome of rigorous research and development. While the grant of patents is subject to establishing novelty and inventive step, it further indicates the technological development and helpful for researchers working in the same technical domain. The aim of the present research work is to map the existing work through analysis of patent literature, in the field of Coronaviruses (CoV), particularly COVID-19 (2019-nCoV). CoV is a large family of viruses known to cause illness in human and animals, particularly known for causing respiratory infections as evidenced in earlier times such as in MERS i.e. Middle East Respiratory Syndrome; SRS i.e. Severe Acute Respiratory Syndrome. A recently identified novel-coronavirus has known as COVID-19 which has currently caused pandemic situation across the globe. Objective: To expand analysis of patents related to CoV and 2019-nCoV. Evaluation has been conducted by patenting trends of particular strains of identified CoV diseases by present legal status, main concerned countries via earliest priority years and its assignee types and inventors of identified relevant patents. We analyzed the global patent documents to check the scope of claims along with focuses and trends of the published patent documents for the entire CoV family including 2019- nCoV through the present landscape. Methods: To extract the results, Derwent Innovation database is used by a combination of different key-strings. Approximately 3800 patents were obtained and further scrutinized and analyzed. The present write-up also discusses the recent progress of patent applications in a period of the year 2010 to 2020 (present) along with the recent developments in India for the treatment options for CoV and 2019-nCoV. Results: Present analysis showed that key areas of the inventions have been focused on vaccines and diagnostic kits apart from the composition for treatment of CoV. We also observed that no specific vaccine treatments is available for treatment of 2019-nCov, however, developing novel chemical or biological drugs and kits for early diagnosis, prevention and disease management is the primarily governing topic among the patented inventions. The present study also indicates potential research opportunities for the future, particularly to combat 2019-nCoV. Conclusion: The present paper analyzes the existing patents in the field of Coronaviruses and 2019-nCoV and suggests a way forward for the effective contribution in this upcoming research area. From the trend analysis, it was observed an increase in filing of the overall trend of patent families for a period of 2010 to the current year. This multifaceted analysis of identified patent literature provides an understanding of the focuses on present ongoing research and grey area in terms of the trends of technological innovations in disease management in patients with CoV and 2019-nCoV. Further, the findings and outcome of the present study offer insights for the proposed research and innovation opportunities and provide actionable information in order to facilitate policymakers, academia, research driven institutes and also investors to make better decisions regarding programmed steps for research and development for the diagnosis, treatment and taking preventive measures for CoV and 2019-nCoV. The present article also emphasizes on the need for future development and the role of academia and collaboration with industry for speedy research with a rationale.


Author(s):  
Reeta Yadav

Employee’s perception regarding fairness in the organization is termed as organizational justice. The objective of this paper is to study the antecedents and consequences of organizational justice on the basis of earlier relevant studies from the period ranging from 1964 to 2015. Previous research identified employee participation, communication, justice climate as the antecedents and trust, job satisfaction, commitment, turnover intentions, organizational citizenship behavior and performance as the consequences of organizational justice. Finding reveals the gaps existing in the literature and gives suggestions for future research work.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1611
Author(s):  
María Cora Urdaneta-Ponte ◽  
Amaia Mendez-Zorrilla ◽  
Ibon Oleagordia-Ruiz

Recommendation systems have emerged as a response to overload in terms of increased amounts of information online, which has become a problem for users regarding the time spent on their search and the amount of information retrieved by it. In the field of recommendation systems in education, the relevance of recommended educational resources will improve the student’s learning process, and hence the importance of being able to suitably and reliably ensure relevant, useful information. The purpose of this systematic review is to analyze the work undertaken on recommendation systems that support educational practices with a view to acquiring information related to the type of education and areas dealt with, the developmental approach used, and the elements recommended, as well as being able to detect any gaps in this area for future research work. A systematic review was carried out that included 98 articles from a total of 2937 found in main databases (IEEE, ACM, Scopus and WoS), about which it was able to be established that most are geared towards recommending educational resources for users of formal education, in which the main approaches used in recommendation systems are the collaborative approach, the content-based approach, and the hybrid approach, with a tendency to use machine learning in the last two years. Finally, possible future areas of research and development in this field are presented.


Risks ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 59
Author(s):  
Grzegorz Ignatowski ◽  
Łukasz Sułkowski ◽  
Bartłomiej Stopczyński

Nepotism and cronyism are forms of favoritism towards certain people in the workplace. For this reason, they constitute a problem for organization managers, ethicists and psychologists. Identifying the impact of COVID-19 pandemic on the increase of nepotism and cronyism may provide a basis for organizations to assess their extent and to take possible measures to prevent their negative effects. At the same time, the research presented in the article may provide a basis for further research work related to nepotism and cronyism at the times of other threats, different from the pandemic. The aim of the article is to examine the impact of the COVID-19 pandemic on growing acceptance for nepotism and cronyism in Polish enterprises. Qualitative and quantitative methods have been included in the conducted research. Qualitative study aimed at improving knowledge of nepotism and cronyism and the impact of the COVID-19 pandemic on these phenomena, followed by a quantitative study conducted in order to verify the information obtained in the qualitative study. This research has demonstrated that Nepotism and cronyism in the workplace, are phenomenon that are basically evaluated negatively. They adversely influences social and economic development, but the impact of COVID-19 pandemic on nepotism and cronyism is not significant.


Author(s):  
M Sreekanth ◽  
R Sivakumar ◽  
M Sai Santosh Pavan Kumar ◽  
K Karunamurthy ◽  
MB Shyam Kumar ◽  
...  

This paper presents a detailed and objective review of regenerative flow turbomachines, namely pumps, blowers and compressors. Several aspects of turbomachines like design and operating parameters, working principle, flow behaviour, performance parameters and analytical and Computational Fluid Dynamics (CFD) related details have been reviewed and summarized. Experimental work has been put in perspective and the most useful results for optimized performance have been presented. Consolidated plots of specific speed-specific diameter have been plotted which can be helpful in the early stages of design. Industrial outlook involving details of suppliers from various parts of the world, their product description and applications too are included. Finally, future research work to be carried out to make these machines widespread is suggested. This review is targeted at designer engineers who would need quantitative data to work with.


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