Every year about one third of the food production intended for humans gets lost or wasted. This wastefulness of resources leads to the emission of unnecessary greenhouse gas, contributing to global warming and climate...
详细信息
Every year about one third of the food production intended for humans gets lost or wasted. This wastefulness of resources leads to the emission of unnecessary greenhouse gas, contributing to global warming and climate change. The solution proposed by the SORT project is to "recycle'' the surplus of food by reconditioning it into animal feed or fuel for biogas/biomass power plants. In order to maximize the earnings and minimize the costs, several choices must be made during the reconditioning process. Given the extremely complex nature of the process, Decision Support Systems (DSSs) could be helpful to reduce the human effort in decision making. In this paper, we present a DSS for food recycling developed using two approaches for finding the optimal solution: one based on Binary Linear programming (BLP) and the other based on Answer Set programming (ASP), which outperform our previous approach based on constraint logic programming (CLP) on Finite Domains (CLP(FD)). In particular, the BLP and the CLP(FD) approaches are developed in (ECLPSe)-P-i, a Prolog system that interfaces with various state-of-the-art Mathematical and constraintprogramming solvers. The ASP approach, instead, is developed in clingo. The three approaches are compared on several synthetic datasets that simulate the operative conditions of the DSS.
Abductive logicprogramming (ALP) has been proven very effective for formalizing societies of agents, commitments and norms, in particular by mapping the most common deontic operators (obligation, prohibition, permiss...
详细信息
Abductive logicprogramming (ALP) has been proven very effective for formalizing societies of agents, commitments and norms, in particular by mapping the most common deontic operators (obligation, prohibition, permission) to abductive expectations. In our previous works, we have shown that ALP is a suitable framework for representing norms. Normative reasoning and query answering were accommodated by the same abductive proof procedure, named SCIFF. In this work, we introduce a defeasible flavour in this framework, in order to possibly discharge obligations in some scenarios. Abductive expectations can also be qualified as dischargeable, in the new, extended syntax. Both declarative and operational semantics are improved accordingly, and proof of soundness is given under syntax allowedness conditions. Moreover, the dischargement itself might be proved invalid, or incoherent with the rules, due to new knowledge provided later on. In such a case, a discharged expectation might be reinstated and hold again after some evidence is given. We extend the notion of dischargement to take into consideration also the reinstatement of expectations. The expressiveness and power of the extended framework, named SCIFFD, is shown by modeling and reasoning upon a fragment of the Japanese Civil Code. In particular, we consider a case study concerning manifestations of intention and their rescission (Section II of the Japanese Civil Code).
Computer Supported Collaborative Learning scripts define pedagogically effective practices for organizing collaborative activities. This paper presents a novel platform for defining CSCL scripts. This platform is comp...
详细信息
ISBN:
(纸本)9783030505059;9783030505066
Computer Supported Collaborative Learning scripts define pedagogically effective practices for organizing collaborative activities. This paper presents a novel platform for defining CSCL scripts. This platform is composed of the following components: a) a formal language named COSTLy for the specification of CSCL scripts based on logic and constraints, b) a visual environment that facilitates the authoring of scripts, based on the formal language, and c) a mechanism that translates the abstract definitions of scripts into constraintlogic programs, thus implementing group formation and task distribution of actual scenario instances. The expressiveness of the proposed language was evaluated. Also the results of a usability evaluation of the proposed platform are reported in the paper. It was shown that university students were able to use the platform in order to describe CSCL scripts of high complexity.
We propose a formal model of block-structured project scheduling with resource constraints, with the goal of designing optimization algorithms. We combine block structured modeling of business processes with results f...
详细信息
ISBN:
(纸本)9783030410322;9783030410315
We propose a formal model of block-structured project scheduling with resource constraints, with the goal of designing optimization algorithms. We combine block structured modeling of business processes with results from project scheduling literature. Differently from standard approaches, here we focus on block structured scheduling processes. Our main achievement is the formulation of an abstract mathematical model of block-structured resource-constrained scheduling processes. We tested the correctness and feasibility of our approach using an initial experimental prototype based on constraint logic programming.
IT projects are characterized by high complexity, implementation of the latest technological solutions and specialized competence of contractors and high costs. The key element in IT project management is to have empl...
详细信息
ISBN:
(纸本)9783030420581;9783030420574
IT projects are characterized by high complexity, implementation of the latest technological solutions and specialized competence of contractors and high costs. The key element in IT project management is to have employees with appropriate substantive competencies (programmers, designers, analysts, etc.). Before starting an IT project, the IT project manager must answer the following questions: Do I have the right set of team competences to start the project? If the team lacks competence, then in what area and to what extent? The article proposes a model of employee competence configuration and a procedure for their verification in the context of IT project management. Also presented is the method of model implementation and numerous computational examples verifying its usefulness and effectiveness of implementation.
The paper presents an optimization model and its implementation using a hybrid approach for the Capacitated Vehicle Routing Problem with Pick-up and Alternative Delivery (CVRPPAD). The development of the CVRPPAD was m...
详细信息
The paper presents an optimization model and its implementation using a hybrid approach for the Capacitated Vehicle Routing Problem with Pick-up and Alternative Delivery (CVRPPAD). The development of the CVRPPAD was motivated by postal items distribution issues. The model proposed combines various features of Vehicle Routing Problem variants. The novelty of this model lies in the introduction of alternativeness of item delivery points, differentiation of delivery point types in terms of their capacity (parcel lockers) and possibility of collecting the items during the execution of delivery routes. The model also takes into account a possibility of introducing time windows related to delivery time. The proposed data structure in the form of sets of facts facilitates the implementation of the model in all environments, constraint logic programming (CLP), Mathematical programming (MP), metaheuristics, databases, etc. The model is implemented in the MP, hybrid CLP/MP, and hybrid CLP/heuristic environments. The hybrid CLP/MP approach is the authors' original solution, which has already been used to solve Supply Chain Management problems, scheduling problems, routing problems etc. For large size problems, considering their combinatorial character, the proposed CLP/MP approach is ineffective. Its effectiveness will improve when MP is replaced by a heuristic. All implementations were performed on the same data instances (facts), which made it possible to compare them according to the solution search time, number of decision variables and number of constraints. The directions into which the model can be further developed were also presented.
Teachers' absences are a common disruption to the provision of academic courses. They make it necessary to modify teacher assignment, which amounts to finding suitable substitutions. Sometimes it happens that the ...
详细信息
A flow production system with concurrently executed supply chains providing material handling/transportation services to a given set of workstations is analyzed. The considered streams of split and merge supply chains...
详细信息
ISBN:
(纸本)9783319999968;9783319999951
A flow production system with concurrently executed supply chains providing material handling/transportation services to a given set of workstations is analyzed. The considered streams of split and merge supply chains representing all the stages at which value is added to a manufacturing product (including the delivery of raw materials and intermediate components are scheduled under constraints imposed by the solution to an associated milk-run vehicle routing problem. A declarative model of the investigated milk-run delivery principle makes it possible to formulate a vehicle routing and scheduling problem, the solution to which determines the route, the time schedule, and the type and number of parts that different trucks must carry to fulfill orders from various customers/recipients. The goal is to find solutions that minimize both vehicle downtime and the takt time of the production flow. The approach proposed allows to view the above trade-off-like problem as a constraint satisfaction problem and to solve it in the Oz Mozart constraintprogramming environment.
constraint logic programming (CLP) is a language scheme for combining two declarative paradigms: constraint solving and logicprogramming. Concurrent constraintprogramming (CCP) is a declarative model for concurrency...
详细信息
ISBN:
(纸本)9783030138387;9783030138370
constraint logic programming (CLP) is a language scheme for combining two declarative paradigms: constraint solving and logicprogramming. Concurrent constraintprogramming (CCP) is a declarative model for concurrency where agents interact by telling and asking constraints in a shared store. In a previous paper, we developed a framework for dynamic slicing of CCP where the user first identifies that a (partial) computation is wrong. Then, she marks (selects) some parts of the final state corresponding to the data (constraints) and processes that she wants to study more deeply. An automatic process of slicing begins, and the partial computation is "depurated" by removing irrelevant information. In this paper we give two major contributions. First, we extend the framework to CLP, thus generalizing the previous work. Second, we provide an assertion language suitable for both, CCP and CLP, which allows the user to specify some properties of the computations in her program. If a state in a computation does not satisfy an assertion then some "wrong" information is identified and an automatic slicing process can start. We thus make one step further towards automatizing the slicing process. We show that our framework can be integrated with the previous semi-automatic one, giving the user more choices and flexibility. We show by means of examples and experiments the usefulness of our approach.
We address the problem of verifying the satisfiability of Constrained Horn Clauses (CHCs) based on theories of inductively defined data structures, such as lists and trees. We propose a transformation technique whose ...
详细信息
We address the problem of verifying the satisfiability of Constrained Horn Clauses (CHCs) based on theories of inductively defined data structures, such as lists and trees. We propose a transformation technique whose objective is the removal of these data structures from CHCs, hence reducing their satisfiability to a satisfiability problem for CHCs on integers and booleans. We propose a transformation algorithm and identify a class of clauses where it always succeeds. We also consider an extension of that algorithm, which combines clause transformation with reasoning on integer constraints. Via an experimental evaluation we show that our technique greatly improves the effectiveness of applying the Z3 solver to CHCs. We also show that our verification technique based on CHC transformation followed by CHC solving, is competitive with respect to CHC solvers extended with induction.
暂无评论