Goto

Collaborating Authors

 Constraint-Based Reasoning


Dependability in Edge Computing

Communications of the ACM

Edge computing is the practice of placing computing resources at the edges of the Internet in close proximity to devices and information sources. This, much like a cache on a CPU, increases bandwidth and reduces latency for applications but at a potential cost of dependability and capacity. This is because these edge devices are often not as well maintained, dependable, powerful, or robust as centralized server-class cloud resources.a This article explores dependability and deployment challenges in the field of edge computing, what aspects are solvable with today's technology, and what aspects call for new solutions. The first issue addressed is failures--both hard (crash, hang, and so on) and soft (performance-related)--and real-time constraint violation.


Achieving Artificial General Intelligence (AGI) using Self Models

#artificialintelligence

"The essence of general intelligence is the capacity to imagine oneself" -- myself Recognize that to gain the perspective that comes from seeing things through another's eyes, you must suspend judgement for a time -- only by empathizing can you properly evaluate another point of view. Moravec's paradox is the observation made by many AI researchers that high-level reasoning requires less computation than low-level unconscious cognition. This is an empirical observation that goes against the notion that greater computational capability leads to more intelligent systems. However, we have today computer systems that have super-human symbolic reasoning capabilities. Nobody is going to argue that a man with an abacus, a chess grandmaster or a champion Jeopardy player has any chance at besting a computer.


Novel Approach for Solving a Variant of Equal Flow Problem

arXiv.org Artificial Intelligence

In this article we consider a certain sub class of Integer Equal Flow problem, which are known NP hard [8]. Currently there exist no direct solutions for the same. It is a common problem in various inventory management systems. Here we discuss a local minima solution which uses projection of the convex spaces to resolve the equal flows and turn the problem into a known linear integer programming or constraint satisfaction problem which have reasonable known solutions and can be effectively solved using simplex or other standard optimization strategies.


Toward XAI for Intelligent Tutoring Systems: A Case Study

arXiv.org Artificial Intelligence

Our research is a step toward understanding when explanations of AIdriven hints and feedback are useful in Intelligent Tutoring Systems (ITS). We added an explanation functionality for the adaptive hints provided by the Adaptive CSP (ACSP) applet, an inte lligent interactive simulation that helps students learn an algorithm for constraint satisfaction problems. We present the design of the explanation functionality and the results of an exploratory study to evaluate how students use it, including an analysis of how students' experience with the explanation functionality is affected by several personality traits and abilities . Our results show a significant impact of a measure of curiosity and the Agreeableness personality trait and provide insight toward des igning personalized Explainable AI (XAI) for ITS .


A case study of Consistent Vehicle Routing Problem with Time Windows

arXiv.org Artificial Intelligence

We develop a heuristic solution method for the Consistent Vehicle Routing Problem with Time Windows (ConVRPTW), motivated by a real-world application at a distribution center of a food company. Additional to standard VRPTW restrictions, ConVRP assigns to each customer just one fixed driver to fulfill their orders during the complete multi-period planning horizon. For each driver and day of the planning horizon, a route has to be determined to serve all their assigned customers with positive demand. The customers do not buy every day and the frequency with which they do so is irregular. Moreover, the quantities ordered change from one order to another. This causes difficulties in the daily routing, negatively impacting the service level of the company. Unlike the previous works on ConVRP, where the number of drivers is fixed a priori and only the total travel time is minimized, we give priority to minimizing the number of drivers. To evaluate the performance of the heuristic, we compare the solution of the heuristic with the routing plan in use by the food company. The results show significant improvements, with a lower number of trucks and a higher rate of orders delivered within the prescribed time window.


Prioritized Unit Propagation with Periodic Resetting is (Almost) All You Need for Random SAT Solving

arXiv.org Artificial Intelligence

We propose prioritized unit propagation with periodic resetting, which is a simple but surprisingly effective algorithm for solving random SAT instances that are meant to be hard. In particular, an evaluation on the Random Track of the 2017 and 2018 SAT competitions shows that a basic prototype of this simple idea already ranks at second place in both years. We share this observation in the hope that it helps the SAT community better understand the hardness of random instances used in competitions and inspire other interesting ideas on SAT solving.


Learning to Dynamically Coordinate Multi-Robot Teams in Graph Attention Networks

arXiv.org Artificial Intelligence

Personal use of this material is permitted. Abstract -- Increasing interest in integrating advanced robotics within manufacturing has spurred a renewed concentration in developing real-time scheduling solutions to coordinate human-robot collaboration in this environment. Traditionally, the problem of scheduling agents to complete tasks with temporal and spatial constraints has been approached either with exact algorithms, which are computationally intractable for large-scale, dynamic coordination, or approximate methods that require domain experts to craft heuristics for each application. We seek to overcome the limitations of these conventional methods by developing a novel graph attention network formulation to automatically learn features of scheduling problems to allow their deployment. T o learn effective policies for combinatorial optimization problems via machine learning, we combine imitation learning on smaller problems with deep Q-learning on larger problems, in a nonparametric framework, to allow for fast, near-optimal scheduling of robot teams. We show that our network-based policy finds at least twice as many solutions over prior state-of-the-art methods in all testing scenarios. I. INTRODUCTION Advances in robotic technology are enabling the introduction of mobile robots into manufacturing environments alongside human workers. By removing the cage around traditional robot platforms and integrating dynamic, final assembly operations with human-robot teams, manufacturers can see improvements in reducing a factory's footprint and environmental costs, as well as increased productivity [1].


Asynchronous Distributed Learning from Constraints

arXiv.org Machine Learning

In this paper, the extension of the framework of Learning from Constraints (LfC) to a distributed setting where multiple parties, connected over the network, contribute to the learning process is studied. LfC relies on the generic notion of "constraint" to inject knowledge into the learning problem and, due to its generality, it deals with possibly nonconvex constraints, enforced either in a hard or soft way. Motivated by recent progresses in the field of distributed and constrained nonconvex optimization, we apply the (distributed) Asynchronous Method of Multipliers (ASYMM) to LfC. The study shows that such a method allows us to support scenarios where selected constraints (i.e., knowledge), data, and outcomes of the learning process can be locally stored in each computational node without being shared with the rest of the network, opening the road to further investigations into privacy-preserving LfC. Constraints act as a bridge between what is shared over the net and what is private to each node and no central authority is required. We demonstrate the applicability of these ideas in two distributed real-world settings in the context of digit recognition and document classification.


Investigating Constraint Programming and Hybrid Methods for Real World Industrial Test Laboratory Scheduling

arXiv.org Artificial Intelligence

Project scheduling includes various problems of high pract ical relevance. Such problems arise in many areas and include different constraints and objectives. Usually pro ject scheduling problems require scheduling of a set of proj ect activities over a period of time and assignment of resources to these activities. Typical constraints include time windows for activities, precedence constraints between the ac tivities, assignment of appropriate resources etc. The aim is to find feasible schedules that optimize several criteria su ch as the minimization of total completion time. In this paper we investigate solving a real-world project sc heduling problem that arises in an industrial test laborato ry of a large company. This problem, Industrial Test Laborator y Scheduling (TLSP), which is an extension of the well known Resource-Constrained Project Scheduling Problem (R CPSP), was originally described in [1, 2]. It consists of a grouping stage, where smaller activities (tasks) are join ed into larger jobs, and a scheduling stage, where those jobs are scheduled and have resources assigned to them. In this wo rk, we deal with the second stage and assume that a grouping of tasks into jobs is already provided.


Data Generation for Neural Programming by Example

arXiv.org Machine Learning

Programming by example is the problem of synthesizing a program from a small set of input / output pairs. Recent works applying machine learning methods to this task show promise, but are typically reliant on generating synthetic examples for training. A particular challenge lies in generating meaningful sets of inputs and outputs, which well-characterize a given program and accurately demonstrate its behavior. Where examples used for testing are generated by the same method as training data then the performance of a model may be partly reliant on this similarity. In this paper we introduce a novel approach using an SMT solver to synthesize inputs which cover a diverse set of behaviors for a given program. We carry out a case study comparing this method to existing synthetic data generation procedures in the literature, and find that data generated using our approach improves both the discriminatory power of example sets and the ability of trained machine learning models to generalize to unfamiliar data.