Optimizing Algerian Company’s Delivery Fleet with Agent_Based Model in Anylogic

Contributors

Contributors

Hybrid simulation modelling in operational research: A state-of-the-art review

Prospective Health Technology Assessment allows early decision making for innovative health care technologies. The main idea is to combine available domain knowledge with advanced simulation techniques in order to predict the effects of medical products and to find bottlenecks and weaknesses within the health system. In our recent publications a hybrid simulation approach with System Dynamics and Agent-Based Modeling has been presented. Hospital workflows have been modeled by state charts within agent behavioral models and have to be instantiated each time an agent is entering a hospital. This paper presents a mechanism to generate agents dynamically from SD models and extends the previously presented hybrid approach by process-oriented Discrete Event Simulation for hospital modeling. It connects processes to health care institutions and not to persons traversing them. Two extended example case studies show potentials for medical decision making using the three simulation paradigms in a common environment.

The paper presents possible solutions to small farmers in the agricultural sector in a small island setting grappling with challenges of enhancing their local industry and import substitution through a supply-demand chain framework. In 2005, Hawaiian farms produced approximately 363,200 kg of avocados. However, Hawaiian demand for these fruits required an additional 908,000 kg of avocados that were supplied through imports. At the same time, it is worth noting; almost 49% of locally produced avocados did not reach the market. These facts clearly suggest inefficiencies in the local avocado supply chain. Review of the literature on supply chain management suggests a sustainable avocado industry requires an integrated supply and demand chain management system. Hence, a modified conceptual model of supply-chain management called the Supply Demand Integrated Management (SDIM) model is proposed in this paper. Traditional supply chains contain three functional components: supply coordination, physical production and logistic management. In the new model, we propose adding R4D (Research for Development), a public good provided by the government to agricultural industries as an integral part of the supply-demand chain system. It articulates the significance of research and supply chain partnerships between small growers, industry groups, and public agencies. A well-integrated demand/supply chain in the avocado industry allows sharing of vital market information which can contribute to long-term strategic decisions that help local avocado growers increase their competitiveness against foreign imports. It also provides metrics in terms of consumer satisfaction, profitability, competitiveness, self-sufficiency, import substitution and sustainability. The SDIM model as applied to the avocado industry suggests two hypotheses relevant to the current situation. The hypotheses are: (1) There is a lack of coordination between what the farmers are growing and the chefs' (a high-end customer/buyer) preferences; (2) Forming an avocado farmer cooperative will enhance the profitability of local farmers. Survey data was collected from Hawaiian chefs and avocado farmers. Data was analysed using a Duncan multi-range test and a mathematical model, respectively, to test the hypotheses. The test revealed a lack of coordination between what the farmers are growing and buyer preferences. The results from the mathematical model suggested that formation of an avocado marketing cooperative would enhance the profitability of local farmers. Thus, the SDIM framework expands existing body of knowledge about supply chain management and provides useful information to local avocado growers that can help strengthen their supply and demand chain management.

Supply chain challenges require not only effective management, but also a new innovative strategy to reduce costs and maximize its efficiency. Traditional problem-solving methodologies specific to the areas of supply chain management (SCM) find their limits when confronted with an inventive problem or a problem containing a contradiction. TRIZ (theory of inventive problem solving) is an effective theory for systematizing innovation and solving complex problems containing contradictions. Thus, the use of the theory TRIZ can be considered as a way to meet future challenges in SCM fields and get innovative solutions. This paper presents a method for solving supply chain problems and achieving a low-cost, based on complementarities between TRIZ and discrete event simulation and specific methods for solving supply chain problems. In the proposed model, a witness simulation model of the initial problem is developed to optimize the problem and find the system limits. Then, specific problem solving methods are applied to change the original description of problem and move towards a space in which a solution can be found. The discrete event simulation allows for experiments on the system to be created and analyzed. Thus, an experimental design was developed to establish the cause-and-effect relationships between the parameters of the system in order to formulate a generalized system of contradictions. And finally, ARIZ 85C, the most mature meta-methods of TRIZ, is used to address related contradictions for searching for an innovative solution, which must be subsequently implemented and evaluated in the discrete event simulation. The suitability of this new approach is finally proven through an industrial case study conducted in a company specialized in the manufacture of electronic devices for automobiles.

Implementation and adoption of new technologies are gaining the result of smooth supply chain and logistics operations. Internet of things (IoT) artificial intelligence, including data mining, intensified in all fields of life, particularly in supply chain management and operations. Blockchain technology has the capability to reform the supply chain and logistics operations management. Blockchain provides digital database solutions for all transactions across supply chain and operations management. Radio frequency identification device (RFID) is also helping technology transmit electromagnetic waves to radio-compatible integrated circuits to look after and manage the entire supply chain and logistics operations management. The Fourth Industry Revolution 4.0 refers to the automation, interconnectivity, machine learning, and real-time data that help supply chain and logistics operations management in the 21st century.

This survey paper starts with a critical analysis of various performance metrics for supply chain management (SCM), used by a specific manufacturing company. Then it summarizes how economic theory treats multiple performance metrics. Actually, the paper proposes to deal with multiple metrics in SCM via the balanced scorecard — which measures customers, internal processes, innovations, and finance. To forecast how the values of these metrics will change — once a supply chain is redesigned — simulation may be used. This paper distinguishes four simulation types for SCM: (i) spreadsheet simulation, (ii) system dynamics, (iii) discrete-event simulation, and (iv) business games. These simulation types may explain the bullwhip effect, predict fill rate values, and educate and train users. Validation of simulation models requires sensitivity analysis; a statistical methodology is proposed. The paper concludes with suggestions for a possible research agenda in SCM. A list with 50 references for further study is included.

КОМПЛЕМЕНТАРНІСТЬ СТРАТЕГІЙ МАРКЕТИНГУ ТА ЛОГІСТИКИ В ЛАНЦЮГУ ПОСТАВОК ТОВАРІВ ПОВСЯКДЕННОГО ПОПИТУ

Objective: The objective of the paper is to investigate the influence of deployment of Information and Communication Technology (ICT) tools in a supply chain context. Methods/Analysis: The influence of deployment of ICT in Supply Chain Management (SCM) is studied using System Dynamics (SD) methodology using the tool, Causal Loop Diagram (CLD) using software Vensim. Findings: SCM discipline is grappled with dynamic and operational changes and challenges and this unpredictability can be understood better using SD. ICT capabilities fundamentally improve supply chain integration and performance. ICT adoption for SCM improves collaboration, workflow and decision-making which lead to cost savings; improved operational efficiency and inventory visibility. One process in SCM namely inventory control is described using SD. Introduction of a parameter, ICT capability dramatically changes the context and gives rise to new positive feedback loops Novelty/Improvements: The paper uses CLD for ICT influence on SCM process of inventory control. This can be extended for all supply chain management processes in both planning and execution. Case studies with the influence of specific ICT tools like RFID, Cloud, Social Media, Business Analytics, Mobile technology and Multi-agent systems are also possibilities for extending the study. Supply chain managers can deliberate on decisions, strategy, issues and policy by developing scenarios using SD tools and software packages. However the research limitation is that this is a simulation in a specific supply chain context. Generalization of this scenario may not be possibleKeywords: Causal Loop Diagram (CLD), Information and Communication Technology (ICT), Inventory, Supply Chain Management (SCM) ICT, System Dynamics (SD)

Discrete-Event Simulation (DES) has been the mainstream in the area of construction simulation. Recently, research has shown the possibility of applying System Dynamics (SD) to the construction management discipline. Unlike DES, which is based on statistical analysis and queuing theory, SD is able to represent the complex system of construction management through capturing feedback effects, managerial actions, and soft variables such as schedule pressure and morale, which are important in determining project behavior. Though SD is capable of representing such variables and relationships, the validity of SD models has often been questioned because when modeling with SD, it is difficult to attain as much detail as when modeling with DES. Therefore, SD has not been fully adopted to simulations in the area of construction management, despite its advantages. To gain widespread use in the construction management area, SD needs to address operational details. In this paper, an SD based earthmoving process model is presented to explore ways in which operation details can be represented using SD. Initially, an SD based earthmoving model is proposed and for the purpose of comparison, and is tested against a DES counterpart model, created using STROBOSCOPE. The tests have shown that the simulation results generated by the SD model are as accurate and reliable as those of the STROBOSCOPE models. The specifics of this comparison are identified, including how the SD model is created from and compared to DES model at an operational level. These research findings support the widespread use of SD in the area of construction management; thus, aiding in the representation of the complexities inherent in construction.

Through an international business risk management lens, the widespread and catalytic implications of the 2020 COVID-19 pandemic on the supply chains (SCs) of fashion multinational corporations (MNC) are analyzed to contribute to existing research on supply chain management (SCM). While a movement towards agile, networked supply chain models had been in consideration for many firms prior to the outbreak, the pandemic highlights issues inherent in supply chains that employ concentrated production. We examined the current state of fashion supply chains, risks that have arisen historically and recently, and existing risk mitigation methods. We found that while lean supply chain management is primarily favored for its cost and waste reduction advantages, the structure is limited by the lack of supply chain transparency that results as well as the increasing demand volatility observed even before the COVID-19 outbreak. Although this problem might exist in the agile supply chain, agile supply chains combat this by focusing on enhancing communication and buyer-supplier relationships to improve information exchange. However, this structure also entails an associated increase in inventory and inventory costs. The COVID-19 pandemic has caused supply and demand disruptions which have resonating effects on supply chain activities and management, indicating a need to build flexibility to mitigate epidemic and demand risks. To address this, several strategies that firms can adopt to control for such risks are outlined and key areas for further research are identified which consider parties both upstream and downstream of the fashion supply chain.

Construction projects are characterized by their dynamic nature and operational details. This paper presents a hybrid simulation methodology; designed to model construction projects. The methodology utilizes Discrete Event Simulation (DES) and System Dynamics (SD). DES has been widely used in modeling construction operations; however, it lacks the ability to model the global aspects of operations being modeled and the cause-effect relations of simulation variables. SD is utilized to circumvent these limitations. Both simulation methods provide valuable decision support but none is individually capable of capturing the holistic nature of the operation being modeled. The developed methodology integrates DES and SD to utilize their respective advantages in simulating construction operations. The developed methodology encompasses five stages: 1) identification of model objectives, 2) decision criteria to assist in selecting simulation methodology, 3) building simulation model and identification of interface variables, 4) computation framework and 5) implementation and testing. The paper describes the essential features of the developed methodology and its computational framework and focuses primarily on the modeling aspects of SD. A case study project is analyzed to demonstrate the use of the developed methodology and to highlight its capabilities.

Background and Purpose: Agent-based modelling and simulation (ABS) is growing in many areas like, e.g., management, social and computer sciences. However, the similar trend does not seem to occur within the field of business process management (BPM), even though simulation approaches like discrete event simulation or system dynamics are well established and widely used. Thus, in our paper we investigate the advantages and disadvantages of agent-based modelling and simulation in the field of BPM in simulation experiments. Design/Methodology/Approach: In our research, we investigate if there is a necessity for ABS in the field of BPM with our own simulation experiments to compare traditional and ABS models. For this purpose, we use simulation framework MAREA, which is a simulation environment with integrated ERP system. Our model is a complex system of a trading company selling computer cables. For the verification of our model, we use automated process discovery techniques. Results: In our simulations, we investigated the impact of changes in resources’ behavior on the outcome of company’s order to cash process (O2C). Simulations experiments demonstrated that even small changes might have statistically significant effect on outcomes of the processes and decisions based on such outcomes. Simulation experiments also demonstrated that the impact of randomly distributed fluctuations of well-being have a diminishing tendency with the increasing number of sales representatives involved in the process. Conclusions: Our research revealed several advantages and disadvantages of using ABS in business process modelling. However, as we show, many of them were at least partially addressed in the recent years. Thus, we believe that ABS will get more attention in the field of BPM similarly to other fields like, e.g., social sciences. We suggested areas in BPM simulations, e.g., modelling of resources, be it human or technological resources, where there is a need for ABS.

According to Akkermans and Dellaert (2005), there are two distinct approaches to computer simulation for supply chain analysis: discrete event simulation (DES) and system dynamics (SD). Both approaches have been used extensively, as reported in the literature (Jahangirian et al., 2010; Tako and Robinson, 2012). However, a number of authors have suggested the use of a hybrid DES/SD simulation for supply chain analysis (Lee et al., 2002; Pereira, 2009; Rabelo et al., 2005; Reiner, 2005; Venkateswaran and Son, 2005). Despite its potential, the literature on supply chain does not report many cases of application of hybrid DES/SD simulation. One limitation preventing its application is the lack of a clear framework to guide its application. Thus in this paper, it is proposed to include the supply chain operations reference model (Supply Chain Council, 2012) as part of the existing frameworks to improve guidelines for the application of hybrid DES/SD simulation.