Agent-based Truck Appointment System for Containers Pick-up Time Negotiation

Congestion in the seaports area is a common issue in many parts of the world. Fluctuating truck arrival has been identified as one of the significant determinants of congestion. In response, a truck appointment system (TAS) is introduced to manage truck arrival, particularly at peak times. In the existing TAS mechanism, the scheduling decision is centralized and disregards the concerns of trucking companies. Moreover, TAS may complicate the business operation of trucking companies that already have a constrained truck schedule. This study proposes a decentralized negotiation mechanism in TAS that allows trucking companies to adjust arrival times by utilizing the waiting time estimation provided by the terminal operator. We develop an agent-based model of a TAS in the container terminal pick-up procedure. The simulation results indicate that compared to the existing TAS mechanism, the negotiation TAS mechanism generates a shorter average truck turnaround time regardless of truck arrival rates. In terms of average net time cost, the negotiation TAS mechanism provides better value under high truck arrival rate conditions. The incentive for trucking companies to participate in the negotiations is even higher at peak times.

Uncertainty Simulation of Wood Chipping Operation for Bioenergy Based on Queuing Theory

Managing uncertainty is the way to secure stability of the supply chain. Uncertainty within chipping operation and chip transportation causes production loss. In the wood chip supply chain for bioenergy, operational uncertainty mainly appears in the moisture content of the material, chipping productivity, and the interval of truck arrival. This study theoretically quantified the loss in wood chip production by applying queuing theory and stochastic modelling. As well as the loss in production, the inefficiency was identified as the idling time of chipper and the queuing time of trucks. The aim of this study is to quantify the influence of three uncertainties on wood chip production. This study simulated the daily chip production using a mobile chipper by applying queuing theory and stochastic modelling of three uncertainties. The result was compared with the result of deterministic simulation which did not consider uncertainty. Uncertainty reduced the production by 14% to 27% compared to the production of deterministic simulation. There were trucks scheduled but not used. The cases using small trucks show the largest daily production amount, but their lead time was the longest. The large truck was sensitive to the moisture content of material because of the balance between payload and volumetric capacity. This simulation method can present a possible loss in production amount and enables to evaluate some ways for the loss compensation quantitatively such as outsourcing or storing buffer. For further development, the data about the interval of truck arrival should be collected from fields and analyzed. We must include the other uncertainties causing technical and operator delays.

Critical points of industrial tomato from field to processing

ABSTRACT The authors evaluated critical points of production stages of the industrial tomato, through physical and physico-chemical analyzes of U2006 hybrid fruits in the harvest, 2016. Fruits were evaluated in relation to raw material, temperature, fresh mass, pH, soluble solids (°Brix), firmness, titratable acidity and extravasation of electrolytes. Samples were collected in six steps: manual, mechanized, truck, arrival at industry, unloading and selection mat in two periods, morning and afternoon, totalizing 60 fruits for each step, and four replications. Fruits which waited for more than 10 hours in the yard generated an increase in serious defects (%), loss of fresh mass, discount on the amount paid for the load. The most critical stages of the production process were identified when tomatoes arrived at the industry and their unloading, when the fruits presented fresh mass loss due to the high temperature. In addition, the authors highlight that a better organization in the arrivals at the industry as well as an efficient communication of crop restriction is crucial, since unscheduled stops increase waiting time, causing significant quality losses.