ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
Unpredictable disruptions (e.g., accidents, traffic conditions, among others) in supply chains (SCs) motivate the development of decision tools that allow designing resilient routing strategies. The transportation problem, for which a model is proposed in this paper, consists of minimizing the stochastic transportation time and the deterministic freight rate. This paper extends a stochastic multi-objective minimum cost flow (SMMCF) model by proposing a novel simulation-based multi-objective optimization (SimMOpt) solution procedure. A real case study, consisting of the road transportation of perishable agricultural products from Mexico to the United States, is presented and solved using the proposed SMMCF-Continuous/SimMOpt solution framework. In this case study, time variability is caused by the inspection of products at the U.S.-Mexico border ports of entry. The results demonstrate that this framework is effective and overcomes the limitations of the multi-objective stochastic minimum cost flow problem (which becomes intractable for large-scale instances).
1. Introduction
The United States is the most important customer for the Mexican ornament flowers industry due to the geographical location of these two countries [1,2]. Road transportation is an affordable transportation method that is available to Mexican suppliers. According to the U.S. Bureau of Transportation Statistics [3], truck and rail transportation of products from Mexico to the United States increased by 3.7 percent, from $34.3 billion in May 2012 to $35.57 billion, in May 2013. Industry analysts expect this trend to continue growing in the near future.
Disruptive events are common in most transportation systems. Accidents, traffic conditions, and weather conditions (among others) are causes of disruptive events. Disruptive events are particularly important when transporting perishable products. The availability of inspection lanes and the process of drug trafficking scan and detection add variability to the crossing time on the U.S.- Mexico border ports of entry. The variability on the waiting time due to security inspections can be translated into important economic impacts [4]. Thus, disregarding factors such as the variability on transportation time results in poorly designed supply chains, which in turn lead to important economic loses [5].
9. Conclusions
The results when considering a deterministic MMCF problem (using expected values of the probability distributions) and when considering the SMMCF-Discrete model can be proved to be statistically different. This implies that solving problems where variability is reduced to expected values of distributions yield results that do not guarantee optimum or near-optimum solutions to MMCF problems with stochastic attributes on arcs.
Discretization of continuously distributed variables implies assuming oversimplifications that do not emulate the real system. This is aggravated when the discrete distributions consider a limited number of classes or when the more realistic continuous distribution show special behavior, such as the multimodal distributions.