Planning as Tabled Logic Programming

This paper describes Picat's planner, its implementation, and planning models for several domains used in International Planning Competition (IPC) 2014. Picat's planner is implemented by use of tabling. During search, every state encountered is tabled, and tabled states are used to effectively perform resource-bounded search. In Picat, structured data can be used to avoid enumerating all possible permutations of objects, and term sharing is used to avoid duplication of common state data. This paper presents several modeling techniques through the example models, ranging from designing state representations to facilitate data sharing and symmetry breaking, encoding actions with operations for efficient precondition checking and state updating, to incorporating domain knowledge and heuristics. Broadly, this paper demonstrates the effectiveness of tabled logic programming for planning, and argues the importance of modeling despite recent significant progress in domain-independent PDDL planners.Comment: 27 pages in TPLP 201

A Strategic Audit of A24

A24 is an independent film production and distribution company founded in 2012. The company performs both duties for independent films as well as television programs, and a small portion of company revenue comes from merchandise it sells in an online kiosk. As of 2021, A24 had around 300 employees while maintaining a large catalog of movies and shows. Using a focus strategy, the company targets a more cultured audience for its unique (and sometimes outright bizarre) subject matter. To achieve this, A24 attempts to cast top B-list personnel both in acting and technical roles in order to corner its market. To understand the company’s strategy, PESTE and Porter’s Five Forces analyses were completed. While there are many outside factors that influence the independent film industry, A24’s consistency of adhering to its core strengths should carry it far and help it continue to grow

Developing and Validating a Scale to Measure Youth Voice

The purpose of this study is to develop and validate a scale to measure the level of engagement of youth in their community or organization using the construct of youth voice. Youth voice consists of three levels: being heard, collaborating with adults, and building leadership capacity. An initial list of 40 items were developed (13 being heard, 13 collaborating with adults, and 14 building leadership capacity). Youth development experts and youth leadership experts were invited to complete a survey to assess the content validity of the items developed for the youth voice scale. The data collected from 50 participants were subjected to the Kendall-Wallis H test and pairwise comparisons. Items that had significant results and appeared to measure the construct that they were designed to measure were then subjected to a factor analysis. The scale was reduced to 29 items (6 being heard, 11 collaborating with adults, and 12 building leadership capacity). The scale serves as a starting point to help youth leadership development practitioners assess the level of youth voice in their programming. Advisor: L.J. McElrav

Manned simulations of the SRMS in SIMFAC

SIMFAC is a general purpose real-time simulation facility currently configured with an Orbiter-like Crew Compartment and a Displays and Controls (D and C) Subsystem to support the engineering developments of the Space Shuttle Remote Manipulator (SRMS). The simulation consists of a software model of the anthropomorphic SRMS manipulator arm including the characteristics of its control system and joint drive modules. The following are discussed: (1) simulation and scene generation subsystems; (2) the SRMS task in SIMFAC; (3) operator tactics and options; (4) workload; (5) operator errors and sources; (6) areas for further work; and (7) general observations

Efficient Declarative Solutions in Picat for Optimal Multi-Agent Pathfinding

The multi-agent pathfinding (MAPF) problem has attracted considerable attention because of its relation to practical applications. The majority of solutions for MAPF are algorithmic. Recently, declarative solutions that reduce MAPF to encodings for off-the-shelf solvers have achieved remarkable success. We present a constraint-based declarative model for MAPF, together with its implementation in Picat, which uses SAT and MIP. We consider both the makespan and the sum-of-costs objectives, and propose a preprocessing technique for improving the performance of the model. Experimental results show that the implementation using SAT is highly competitive. We also analyze the high performance of the SAT solution by relating it to the SAT encoding algorithms that are used in the Picat compiler