Hybrid Modelling for Vineyard Harvesting Operations

Hiring workers under seasonal recruiting contracts causes significant variation of workers skills in the vineyards. This leads to inconsistent workers performance, reduction in harvesting efficiency, and increasing in grape losses rates. The objective of this research is to investigate how the variation in workers experience could impact vineyard harvesting productivity and operational cost. The complexity of the problem means that it is difficult to analyze the system parameters and their relationships using individual analytical model. Hence, a hybrid model integrating discrete event simulation (DES) and agent based modeling (ABM) is developed and applied on a vineyard to achieve research objective. DES models harvesting operation and simulates process performance, while ABM addresses the seasonal workers heterogeneous characteristics, particularly experience variations and disparity of working days in the vineyard. The model is used to evaluate two seasonal recruiting policies against vineyard productivity, grape losses quantities, and total operational cost

Contract Farming in the Mekong Delta's Rice Supply Chain: Insights from an Agent-Based Modeling Study

We would like to thank Michael Maes and the anonymous reviewers for their insightful and constructive feedback. The first author, H. K. Nguyen, would like to acknowledge support from an Australian Government Research Training Program scholarship to study a PhD degree in Computer Science at The University of Newcastle, Australia. R. Chiong is the corresponding author of this paper. The third author, M. Chica, is supported through the Ramón y Cajal program (RYC-2016-19800)In this paper, we use agent-based modeling (ABM) to study different obstacles to the expansion of contract rice farming in the context of Mekong Delta (MKD)'s rice supply chain. ABM is a bottom-up approach for modeling the dynamics of interactions among individuals and complex combinations of various factors (e.g., economic, social or environmental). Our agent-based contract farming model focuses on two critical components of contractual relationship, namely financial incentives and trust. We incorporate the actual recurrent fluctuations of spot market prices, which induce both contractor and farmer agents to renege on the agreement. The agent-based model is then used to predict emergent system-wide behaviors and compare counterfactual scenarios of different policies and initiatives on maintaining the contract rice farming scheme. Simulation results firstly show that a fully-equipped contractor who opportunistically exploits a relatively small proportion (less than 10%) of the contracted farmers in most instances can outperform spot market-based contractors in terms of average profit achieved for each crop. Secondly, a committed contractor who offers lower purchasing prices than the most typical rate can obtain better earnings per ton of rice as well as higher profit per crop. However, those contractors in both cases could not enlarge their contract farming scheme, since either farmers' trust toward them decreases gradually or their offers are unable to compete with the benefits from a competitor or the spot market. Thirdly, the results are also in agreement with the existing literature that the contract farming scheme is not a cost-effective method for buyers with limited rice processing capacity, which is a common situation among the contractors in the MKD region. These results yield significant insights into the difficulty in expanding the agricultural contracting program in the MKD's rice supply chain.Ramón y Cajal program (RYC-2016-19800

Aportes teórico-conceptuales acerca del cambio organizacional de la industria cafetera colombiana

ResumenLa transformación del sector cafetero se puede analizar bajo la óptica del cambio en los campos organizacionales que permite señalar y anticipar fallas que generen desestabilización. El presente artículo analiza la forma como se desarrolla el cambio en los campos organizacionales a partir del emprendimiento institucional en el caso de la industria cafetera colombiana desde una perspectiva teórico-conceptual. En ese sentido, se realiza una revisión de literatura académica en 4 niveles: campo organizacional, cambio organizacional en campos organziacionales, emprendimiento institucional, cambio organizacional a partir del emprendimiento institucional. Se encuentra una fuerte relación entre varios de los elementos señalados en la literatura que describen el cambio organizacional a partir del emprendimiento institucional y el cambio en el sector cafetero colombiano.AbstractThe transformation of the coffee sector can be analysed under the perspective of change in organisational fields that enables failures that generate destabilisation to be signalled and anticipated. This article analyses the way how change is developed in the organisational fields by institutional entrepreneurship in the case of the Colombian coffee industry from a theoretical-conceptual perspective. To do this, a review was carried out on the academic literature at four levels: organisational field, organisational change in organisational fields, institutional entrepreneurship, organisational change from institutional entrepreneurship. A strong relationship is found between several of the elements pointed out in the literature that describe organisational change from institutional entrepreneurship and the change in the Colombian coffee sector

Hybrid modeling for vineyard harvesting operations

Hiring workers under seasonal recruiting contracts causes significant variation of workers skills in the vineyards. This leads to inconsistent workers performance, reduction in harvesting efficiency, and increasing in grape losses rates. The objective of this research is to investigate how the variation in workers experience could impact vineyard harvesting productivity and operational cost. The complexity of the problem means that it is difficult to analyze the system parameters and their relationships using individual analytical model. Hence, a hybrid model integrating discrete event simulation (DES) and agent based modeling (ABM) is developed and applied on a vineyard to achieve research objective. DES models harvesting operation and simulates process performance, while ABM addresses the seasonal workers heterogeneous characteristics, particularly experience variations and disparity of working days in the vineyard. The model is used to evaluate two seasonal recruiting policies against vineyard productivity, grape losses quantities, and total operational cost

Applications of agent-based modelling and simulation in the agri-food supply chains

Agri-food supply chains (ASC) are an important application domain for Operational Research/Management Science. In particular, the use of agent-based simulation (ABS) has increased in ASC research in recent years. This paper reviews existing ASC research that use ABS. The review begins by analysing the characteristics of the models and modelling reported in the literature. It illustrates that existing modelling research features extensive use of: single echelon supply chains; cases from high and middle income countries; unprocessed food products, empirical (as opposed to hypothetical) data; decision-making related to production planning and investment; and the use of black box validation. The second part of the review uses bibliographic mapping to analyse areas in ASC research which are yet to be addressed using ABS. We find that areas such as collaboration and competition, buyer–seller relationships, and service are under-researched. In addition, key actors in ASC such as food processors, supermarkets and retailers have not been included in the ABS models reported. Furthermore, these models have yet to incorporate important supply chain management theories such as Transaction Cost Economics and Resource-Based View as part of their design

Improving and comparing data collection methodologies for decision rule calibration in agent-based simulation : a case study of dairy supply chain in Indonesia

This study contributes to human behaviour (decision rule) modelling in the agent based simulation, by improving the existing data collection methodologies and comparing their benefits. Improving data collection methodologies can help in developing a more realistic agent’s decision rule and increasing the validity and credibility of the final model. This study uses a dairy supply chain case because the actors in this context can have one to one correspondence with the agents in the simulation. This study begins by presenting a literature review on the applications of agent-based simulation in the agri-food supply chain. This literature review highlights existing agent-based modelling practices in the agri-food supply chain such as the scope of the modelling, data collection, validation and sensitivity analysis techniques. This study then proposes some improvements to the existing data collection methodologies namely questionnaire survey and role-playing game. This study proposes the use of a scenariobased questionnaire to improve the benefits of a questionnaire survey for decision rules calibration. While to extend the usefulness of role-playing game this study propose the use of the design of experiment, and game scaling based on empirical probability distribution. The improved data collection methods are then used to calibrate a base model that was developed from the previous literature. Primary data from 16 villages in Indonesia is used to elicit empirical decision rules in this calibration process. The result from simulation experiments shows that the improved data collection methods can produce models with higher operational validity. This study is concluded by evaluating the advantages and disadvantages of each data collection methodology

Integration of lean six sigma with multi agent systems in the food distribution industry in small to medium enterprises

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe service industry worldwide continues to face unprecedented challenges in decision-making and in managing the operations involved in delivering products at low cost and ever-faster delivery speeds. These pressures exert an even greater impact upon small- and medium-sized enterprises (SMEs) involved in this industry who, influenced by globalisation, have to respond by handling the dynamic complexity within their operational supply chain. Many larger firms have implemented Lean and Six Sigma (LSS) and end-to-end integrated real-time information systems (RTI) that provide the information and the mechanisms needed to support flexibility and prompt decision-making. The recent emergence of new technologies such as multi-agent systems (MAS) provides enhanced capability to address complexity and decision-making with greater ease of use at a reduced cost. Whilst the application of Lean and Six Sigma are supported by significant published research, the application of integrated LSS and MAS in food distribution, especially in SMEs, is not. This study seeks to provide research to address this shortcoming for SMEs within the food distribution sector within Saudi Arabia, how this integrated approach can offer considerable performance improvement in SMEs and provide a base for further contributions in this field. This research undertook an empirical case study in Saudi Arabia to test the application of LSS in a food distribution SME. This approach demonstrated a significant improvement in the Six Sigma for late delivery. A single-stage MAS application extended this improvement, demonstrating that there is value in its application. The study conducted a survey of 39 firms in this sector to gain an insight into their current practices and challenges. The findings indicated there was a lack of Lean and Six Sigma principles adopted and that a lack of use of interconnected real-time systems to support decision-making and complex operational SCs. These findings identified the opportunity to design a conceptual framework with a stepped approach that integrated LSS with MAS, which was then developed on a Java-Assisted DEvelopment Framework (JADE) platform and tested using real-world data in an SME empirical case study. The results of the sequence of applications and the final simulations proved that this integrated Lean multi-agent system (LMAS) solution offered such substantial improvements in quality, time and costs that the SME considered that those factors justified making its implementation a priority