Dynamic simulation methodology for implementing circular economy: A new case study

Purpose: Circular economy (CE) principles have evolved in response to natural resource depletion as a set of guidelines for eliminating the linear take-use-dispose model of product consumption. The consequences of shifting from a linear to a circular supply chain are difficult to visualize in the long term. This study aims to design a methodology for building a simulation model to implement CE strategies in any small and medium-sized enterprise SME to prove policies before implementing them in the real world. This paper applied the methodology in a biological cycle case study: a confectionery factory in Mexico. Design/methodology/approach: This study evaluated service-dominant logic, ecosystem services, system dynamics, and agent-based modeling to design the proposed methodology. A series of interviews with stakeholders were performed to assess the simulation model during the development phase. The circular economy indicator prototype (CEIP) was used as a circular maturity measure of the confectionery factory. The simulator was executed in Netlogo software, implementing a four-scenario analysis based on two CE policies for the caramel recycling process. Five state variables were proposed in this analysis: confectionery waste, recycled glucose, recycling utilization, costs of recycled glucose, and profit. Findings: The CEIP score of the confectionery factory was 52%, rated as a “good” product. Regarding scenario analysis, the first scenario had the highest profit improvement. Practical implications: The simulator allowed stakeholders to understand the operation of the recycling process and visualize all variables involved in the system. Originality/value: In the CE literature, little attention has been paid to proposing a methodology for designing a simulation model to implement CE strategies in any industry. Thus, this study implements a nine-step methodology based on services context and dynamic simulation tools to design a platform to evaluate and visualize the consequences of CE strategies implementation in the long termPeer Reviewe

Analisis Pemilihan Moda dari Mobil Pribadi ke Bus Trans Lampung di Bandar Udara Raden Inten II Lampung

The purpose of this study is to identify factors that influence the choice of mode from private cars to Transs Lampung Buses and to analyze the selection model and can explain the probability of modal choice from private cars to Trans Lampung Buses, using random sampling techniques. The data was obtained through the results of the quisioner filler with binary logic method and PSPP analysis. Based on the results of the correlation test between the dependent variable and the independent variable, the Transportation Tool Used to Go to the Airport (X6), the Transportation Tool Used to Leave the Airport (X7) and the Trans Lampung Bus Leisure Consideration (X8) have a significance of 0,000; 0,000 and 0,041. This significance has a value of less than 0.05 which means that it correlates with the dependent variable. To find out the differences in the tendency of each vari - able that correlates can multiple linear regression equation Y = - 2.23 + 15.46 X6 + 13.48 X7 + 11.52 X8. Based on the probability test results of the 3 correlating variables produce scenario 1 the probability of a private car is 9.7% and the probability of Trans Lampung Bus is 90.3%. Scenario 2 generates 99% probability of private cars and the probability of Trans Lampung buses is 1%. Scenario 3 generates the probability of a private car of 8% and the probability of a Trans Lampung bus of 92

Thou Shalt is not You Will

In this paper we discuss some reasons why temporal logic might not be suitable to model real life norms. To show this, we present a novel deontic logic contrary-to-duty/derived permission paradox based on the interaction of obligations, permissions and contrary-to-duty obligations. The paradox is inspired by real life norms

Multi-Criteria Optimal Planning for Energy Policies in CLP

In the policy making process a number of disparate and diverse issues such as economic development, environmental aspects, as well as the social acceptance of the policy, need to be considered. A single person might not have all the required expertises, and decision support systems featuring optimization components can help to assess policies. Leveraging on previous work on Strategic Environmental Assessment, we developed a fully-fledged system that is able to provide optimal plans with respect to a given objective, to perform multi-objective optimization and provide sets of Pareto optimal plans, and to visually compare them. Each plan is environmentally assessed and its footprint is evaluated. The heart of the system is an application developed in a popular Constraint Logic Programming system on the Reals sort. It has been equipped with a web service module that can be queried through standard interfaces, and an intuitive graphic user interface.Comment: Accepted at ICLP2014 Conference as Technical Communication, due to appear in Theory and Practice of Logic Programming (TPLP

Prescribed Performance Control Guided Policy Improvement for Satisfying Signal Temporal Logic Tasks

Signal temporal logic (STL) provides a user-friendly interface for defining complex tasks for robotic systems. Recent efforts aim at designing control laws or using reinforcement learning methods to find policies which guarantee satisfaction of these tasks. While the former suffer from the trade-off between task specification and computational complexity, the latter encounter difficulties in exploration as the tasks become more complex and challenging to satisfy. This paper proposes to combine the benefits of the two approaches and use an efficient prescribed performance control (PPC) base law to guide exploration within the reinforcement learning algorithm. The potential of the method is demonstrated in a simulated environment through two sample navigational tasks.Comment: This is the extended version of the paper accepted to the 2019 American Control Conference (ACC), Philadelphia (to be published

PS-LTL for constraint-based security protocol analysis

Several formal approaches have been proposed to analyse security protocols, e.g. [2,7,11,1,6,12]. Recently, a great interest has been growing on the use of constraint solving approach. Initially proposed by Millen and Shmatikov [9], this approach allows analysis of a finite number of protocol sessions. Yet, the representation of protocol runs by symbolic traces (as opposed to concrete traces) captures the possibility of having unbounded message space, allowing analysis over an infinite state space. A constraint is defined as a pair consisting of a message M and a set of messages K that represents the intruder¿s knowledge. Millen and Shmatikov present a procedure to solve a set of constraints, i.e. that in each constraint, M can be built from K. When a set of constraints is solved, then a concrete trace representing an attack over the protocol can be extracted. \ud Corin and Etalle [4] has improved the work of Millen and Shmatikov by presenting a more efficient procedure. However, none of these constraint-based systems provide enough flexibility and expresiveness in specifying security properties. For example, to check secrecy an artificial protocol role is added to simulate whether a secret can be learned by an intruder. Authentication cannot also be checked directly. Moreover, only a built-in notion of authentication is implemented by Millen and Shmatikov in his Prolog implementation [10]. This problem motivates our current work. \ud A logical formalism is considered to be an appropriate solution to improve the flexibility and expresiveness in specifying security properties. A preliminary attempt to use logic for specifying local security properties in a constraint-based setting has been carried out [3]. Inspired by this work and the successful NPATRL [11,8], we currently explores a variant of linear temporal logic (LTL) over finite traces, -LTL, standing for pure-past security LTL [5]. In contrast to standard LTL, this logic deals only with past events in a trace. In our current work, a protocol is modelled as in previous works [9,4,3], viz. by protocol roles. A protocol role is a sequence of send and receive events, together with status events to indicate, e.g. that a protocol role has completed her protocol run. A scenario is then used to deal with the number of sessions and protocol roles considered in the analysis. \ud Integrating -LTL into our constraint solving approach presents a challenge, since we need to develop a sound and complete decision procedure against symbolic traces, instead of concrete traces. Our idea to address this problem is by concretizing symbolic traces incrementally while deciding a formula. Basically, the decision procedure consists of two steps: transform and decide. The former step transforms a -LTL formula with respect to the current trace into a so-called elementary formula that is built from constraints and equalities using logical connectives and quantifiers. The decision is then performed by the latter step through solving the constraints and checking the equalities. \ud Although we define a decision procedure for a fragment of -LTL, this fragment is expressive enough to specify several security properties, like various notions of secrecy and authentication, and also data freshness. We provide a Prolog implementation and have analysed several security protocols. \ud There are many directions for improvement. From the implementation point of view, the efficiency of the decision procedure can still be improved. I would also like to investigate the expressiveness of the logic for speficying other security properties. This may result in an extension of the decision procedure for a larger fragment of the logic. Another direction is to characterize the expressivity power of -LTL compared to other security requirement languages