Intermodal Competition: Cargo Airships versus Long-Haul Trucking for Perishable Commodities

Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne-kilometer cost of trucking rises much more quickly with distance than it does the cost of a cargo airship. At some distance, the two modes are direct substitutes. The costs of the Mexico-Canada refrigerated truck supply chain are compared with the costs of a 100t-lift, electrically-powered airship. The flight characteristics of the Hindenburg Zeppelin are used as a model for a modern cargo airship. The supply chain cost of trucking tomatoes is used to test the theorical proposition. The cost difference works out to about US10￠/kg (5￠/lb) advantage for trucking Mexican tomatoes to Canada. However, this cost disadvantage of the airship could be made up by their vibrationless ride, better air circulation and one-day service versus four days by truck. This alternative form of transportation could have a positive impact on worldwide north-south distribution of food. Airships can overcome trade barriers and distance to open new markets for perishable food exports. In addition, they would reduce the carbon emissions of transport. Canada imports 160,000 refrigerated truckloads of fruits and vegetables by from the southern US and Mexico. With an average driving distance of 3,000 km, these trucks emit 606,000 MT of CO2 annually. Airships powered by hydrogen fuel cells would have zero-carbon emissions. Markets are not yet incorporating the environmental advantage of airships in any freight comparison, but inevitably this will be important.

Reliability supply chain network design model for perishable products

The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is defined by introducing the probability that a facility may be prone to inactivity based on the analysis of perishable product characteristics.The perishable product SCN design problem is formulated as a 0-1 integer programming model.The objective is to minimize the weighted sum of the operating cost(the fixed plus transportation cost)and the expected failure cost.And then,the perishable product SCN design model is discussed and solved using the genetic algorithm(GA).The results show how to generate the tradeoff curve between the operating costs and the expected failure costs.And these tradeoff curves demonstrate empirically that substantial improvements in reliability are often possible with minimal increase in the operating costs.

Publish or Perish被引分析工具在外语教学研究中的应用

被引分析是最常见的科学计量学研究方法,主要用来证明作者或其成果在所属专业领域内的影响力。Publish or Perish是一种在线被引分析软件,依据Google Scholar数据库来查询作者或成果的被引次数,并提供相关的统计数据分析。文章主要介绍了该工具的功能及使用方法,并结合实例探讨了其在外语教学研究中的应用。

Model of Combined Transport of Perishable Foodstuffs and Safety Inspection Based on Data Mining

There is still no effective means to analyze in depth and utilize domestic mass data about agricultural product quality safety tests in china now. The neural network algorithm, the classification regression tree algorithm, the Bayesian network algorithm were selected according to the principle of selecting combination model and were used to build models respectively and then combined, innovatively establishing a combination model which has relatively high precision, strong robustness and better explanatory to predict the results of perishable food transportation meta-morphism monitoring. The relative optimal prediction model of the perishable food transportation metamorphism monitoring system could be got. The relative perfect prediction model can guide the actual sampling work about food quality and safety by prognosticating the occurrence of unqualified food to select the typical and effective samples for test, thus improving the efficiency and effectiveness of sampling work effectively, so as to avoid deteriorated perishable food’s approaching the market to ensure the quality and safety of perishable food transportation. A solid protective wall was built in the protection of general perishable food consumers’ health.

A Note on an Economic Lot-sizing Problem with Perishable Inventory and Economies of Scale Costs:Approximation Solutions and Worst Case Analysis

This paper presents an economic lot-sizing problem with perishable inventory and general economies of scale cost functions. For the case with backlogging allowed, a mathematical model is formulated, and several properties of the optimal solutions are explored. With the help of these optimality properties, a polynomial time approximation algorithm is developed by a new method. The new method adopts a shift technique to obtain a feasible solution of subproblem and takes the optimal solution of the subproblem as an approximation solution of our problem. The worst case performance for the approximation algorithm is proven to be （4√2 ＋ 5）/7. Finally, an instance illustrates that the bound is tight.

Intermodal Freight Network Design for Transport of Perishable Products

The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.

Study of the Option Ordering Policy concerning Perishable Farm Produce Based on Revenue Sharing Contract

This paper considers the two-echelon supply chain system which consists of single agricultural producers and retailers,and analyzes the impact of sharing ratio on the option ordering quantity,and retailers and producers' expected profits.Studies have shown that in the case of decentralization,when the revenue sharing ratio is between 0 and 0.3,the option ordering quantity of farm produce is a decreasing function of the sharing ratio; when the revenue sharing ratio is between 0.3 and 1,the option ordering quantity of farm produce is an increasing function of sharing ratio; when the revenue sharing ratio is between 0.421 and 1,the agricultural producers and retailers' expected profits are an increasing function of sharing ratio.Finally,through the numerical calculation,the applicability of the conclusions is verified,to provide a reference for the supply chain management practices.

An Inventory Model for Perishable Items with Time Varying Stock Dependent Demand and Trade Credit under Inflation

In the classical inventory models, it is assumed that the retailer pays to the supplier as soon as he received the items and in such cases the supplier offers a cash discount or credit period (permis-sible delay) to the retailer. In this paper we presented an inventory model for perishable items with time varying stock dependent demand under inflation. It is assumed that the supplier offers a credit period to the retailer and the length of credit period is dependent on the order quantity. The purpose of our study is to minimize the present value of retailer’s total cost. Numerical examples are also given to demonstrate the presented mode.

DYNAMIC PRICING UNDER TEMPERATURE CONTROL FOR PERISHABLE FOODS

Consumers pay more and more attention to the quality of perishable roods, which is mainly affected by storage temperature. This paper presents a dynamic pricing model for perishable foods under temperature control. To maximize the total profit, the optimal price and storage temperature are obtained using Pontryagin＇s maximum principle. A static pricing model is provided to compare with the dynamic one. It is shown by a numerical example that the dynamic policy can make more revenue than the static one. Moreover, the managerial implications are analyzed and the effectiveness of the proposed method is demonstrated.

COORDINATING PRICING, ORDERING AND ADVERTISING FOR PERISHABLE PRODUCTS OVER AN INFINITE HORIZON

Numerous empirical studies show that advertising effort can stimulate demand in both current and future periods, and there is an interaction between pricing, advertising and ordering decisions. How do these decisions interact with each other and what is the effect of advertising on pricing and ordering decisions？ To understand this interaction, we consider a newsvendor-type firm that sells a perishable product in a stable market and dynamically determines the joint ordering, pricing and advertising strategies. The problem is modeled as an infmite horizon newsvendor problem with an advertising carryover effect and price-sensitive demand. We characterize the optimal pricing, advertising and inventory strategies and their comparative statics, and consider how this policy differs from the traditional approach without the advertising effect. We show that the optimal effective advertising level is monotonically increasing with the effective advertising level in the previous period, and hence the optimal strategies （advertising, pricing, inventory level） globally converge to the steady states in the long run. We numerically show that the optimal policy can reap significant profit, which underscores the importance of the advertising-driven ordering and pricing strategies.

An EOQ model with backordering for perishable items under multiple advanced and delayed payments policies

This study investigated an economic order quantity (EOQ) model with completebackorder for fixed lifetime perishable items under multiple advance and delayedpayments policies. Here, a new type of business policy is consideredwhere supplieroffers the retailer to pay a fraction of the purchasing cost before the order deliverybymultiple equal installments starting from the ordering time and the rest amountafter the delivery by multiple equal installments. Here, some theoretical results areillustrated to determine the conditions of existence and uniqueness of the optimalsolutions. A closed form solution is determined to solve the proposed model underapproximation. Some numerical examples are provided to examine the validity ofthe proposed model. Finally, sensitivity analyses are presented to obtain the effectof optimal policy and provide some managerial insights of the model.

The risk management of perishable supply chain based on coloured Petri Net modeling

The supply chain of perishable products is a combination of information organization,sharing and integration.The information modeling of supply chain is constructed to abstract key quality information including environment information,processing procedures and product quality assessments based on principle of quality safety factors and property of decay rate.The coloured Petri Net is applied for integrated description of independent information classification,aiming at risk identification and risk management framework.Well,according to the quality deterioration tendency,risk grades management and decision-making system are established.Practically,the circulation system of aquatic products is studied in this paper for full processing description.The simulation experiments are manipulated on environmental information,processing information and product quality information by the coloured Petri Net.Eventually,the conclusion turns out precisely as such that the coloured Petri Net conclusive for information classification and information transmission while integrated information management is available of efficient risk identification and decision-making system in supply chain of perishable products.Meanwhile,the validity of evaluating management and shelf-life estimation of perishable products are technically feasible.

Production plan for perishable agricultural products with two types of harvesting

Many crops in China have two or more harvesting methods;however,little research has focused on this phenomenon.The current study proposes an operational model that looks to maximize grower profits.This model considers a production plan for a perishable crop that has two harvesting methods:harvesting unripe produce at a lower operational cost but with a long lead time,and harvesting ripe crops at a higher operational cost but with quick turnaround.This study proposes a heuristic algorithm by which to pinpoint the optimal plan for the model;the model results indicate that for a crop with two harvesting methods,significant savings can be obtained by applying an optimal production plan.The current study’s main contribution is a production model for crops that feature two harvesting methods and for which the market poses varying demands.

Inventory Policy and Heuristic for Long-Term Multi-product Perishable Inventory Routing Problem with Static Demand

This work considers a long-term Perishable Inventory Routing Problem with multiple products,static demand,and single vehicle,in the setting of Vendor Managed Inventory.By analyzing the optimal solutions of long-term cases that can be solved in Python+Gurobi within 2 h,we capture some patterns of optimal solutions.Utilizing these patterns,experiments show that under certain conditions,the mathematical models of multi-product problems could be simplified to single-product problems,which have the same optimal solutions while taking less time to solve.Managerial insights were generated that for products with static demand in the long term,delivery should be arranged at the store level rather than at the product level.Products in the same store should have the same delivery pattern,no matter how different the unit holding costs are.By further analyzing the optimal solutions of the simplified models,we find that optimal value will stabilize in the long term,and the optimal solution is very close to the solution point where total inventory holding cost and transportation cost are close.Based on these findings,we have developed a heuristic that always provides optimal or close-to-optimal solutions with far less computational time,compared with Python+Gurobi.

On the Quasi-Concavity of Equipment Sharing Games with Perishable Raw Materials

We study the equipment sharing problem where a group of food&beverage companies share the same equipment of a contractor and wish to have their processing tasks coordinated such that the total cost is minimized.The raw materials to be processed are perishable,which incur a decay cost as time goes.One key issue of this equipment sharing problem is how to allocate the total cost among the participants.We apply cooperative game theory to tackle this issue and formulate the problem as an equipment sharing game.First,we study the 1-equipment sharing game in which all participants share one equipment.We show that the 1-equipment sharing game is quasi-concave when the fixed operation cost is larger than a certain value.We then discuss the special case where the processing time for all participants is equal.For this case,we further investigate the properties of the 1-equipment sharing game and the multi-equipment sharing game.We identify the conditions under which the Shapely value and the T-value can be easily calculated for the 1-equipment and multi-equipment sharing games.

A literature review of perishable medical resource management

In recent decades,healthcare providers have faced mounting pressure to effectively manage highly perishable and limited medical resources.This article offers a comprehensive review of supply chain management pertaining to such resources,which include transplantable organs and healthcare products.The review encompasses 93 publications from 1990 to 2022,illustrating a discernible upward trajectory in annual publications.The surveyed literature is categorized into three levels:Strategic,tactical,and operational.Key problem attributes and methodologies are analyzed through the assessment of pertinent publications for each problem level.Furthermore,research on service innovation,decision analytics,and supply chain resilience elucidates potential areas for future research.

To Be or Not to Be?The“Publish or Perish”Syndrome for English Teacher Educators in China

The philosophy of“publish or perish”has already been adopted as a yardstick by the vast majority of Chinese higher education institutions in their attempts to benchmark Western research universities in recent years,which has led to increasing pressure on university teachers to produce research publications.This paper addresses this endemic issue in China’s teaching universities with particular reference to its impact on English teacher educators.It points out that this trend is a result of unrealistically benchmarking research universities in well-resourced Western countries and overlooking the nature of teaching universities,the nature of English teacher educators’professional commitments,and the practical constraints on China’s teaching institutions.It has given rise to a variety of problems which,unless addressed properly,may demoralize English teacher educators and impair the quality of both teaching and research.The paper argues that a fair perception of and attitude towards research and realistic expectations of English teacher educators’research outcomes are essential.Practical implications at macro-,meso-and micro-levels are provided with the aim of improving the status quo.

考虑个体客户满意度的多车程生鲜品配送路径优化

随着生鲜电商的兴起,生鲜品的道路运输量越来越大,其配送任务越来越复杂,提升客户满意度是生鲜品配送的重要目标组成。文章以一个具有配送自主权的生鲜品供应商为研究对象,以整个计划周期内生鲜品配送的车辆运输成本最小及客户满意度最大为双目标,且客户满意度从顾客的个体视角考虑,构建双目标多车程带时间窗及考虑订单打包时间的车辆路径优化模型。基于ε-约束方法,设计了两阶段变邻域搜索(VNS)和模拟退火(SA)相结合的元启发式算法,基于车辆构造初始路线,并针对性地提出了3点改进措施,包括通过数学性质推导下界、减少求解过程中不必要的搜索空间以及规避求解过程中被支配解的后优化处理。最后,以Solomon标准算例为基础构造算例对所设计的算法进行了计算实验,其求解结果表明:其设计的算法具有有效性,并通过敏感性分析得出相关管理启示。

多维技术赋能易腐水果智能包装设计研究

目的寻求易腐水果包装智能设计的创新策略,在更好保护水果的同时延长易腐水果的保鲜期,提升易腐水果的附加值。方法调研当今市场上樱桃、草莓、猕猴桃、杨梅等易腐水果包装的弊病,明确设计的新方向,以安全为出发点,以新型技术为着力点,结合实例探索易腐水果包装智能设计的策略与方法。结果将生物基PH响应智能膜运用其中,可以实时监测水果状态。通过创新的包装结构,在盒中设置多孔外壁有效防止了水果因大量乙烯释放造成的腐烂现象的发生。可折叠性的包装结构更加保证了水果在流通环节中的新鲜度,数字化信息技术的渗融使得防伪技术更好甄别产品真假。结论易腐水果对包装有着相对特殊的要求,宜于从安全性、环保性、人文性角度进行考量,通过功能性包装材料运用、智慧型包装结构创意以及数字化技术赋能等方法与技术,实现包装智能化,为水果保鲜、护形、溯源、防伪等提供帮助,构建多重安全屏障。在强化特定水果品牌意识的同时提升大众的购物体验和健康消费幸福感指数。

考虑策略型消费者后悔行为的易逝品零售商最优库存策略

易逝品零售商降价销售时,策略型消费者往往会经历高价后悔和缺货后悔,这两种后悔行为均会降低他们的购买效用,从而影响零售商库存决策和利润。因此,本文分别研究了价格外生和内生两种情形下高价后悔和缺货后悔对策略型消费者行为以及零售商库存决策和利润的影响。研究表明,对于高利润产品,零售商应实施瞄准短视型消费者(target myopic consumers,TMC)的策略。相反,对于低利润产品,零售商应实施瞄准短视和策略型消费者(target both myopic and strategic consumers,TBC)的策略。此外,随着高价(缺货)后悔水平的增加,策略型消费者原来认为是低(高)利润的产品,现在可能认为是高(低)利润产品,因此零售商最优策略可能会相应地改变。其次,对于低利润产品,当高价(缺货)后悔显著时,后悔行为对零售商产生负(正)影响,且高价后悔和缺货后悔呈现相反的作用;对于高利润产品,后悔行为不对零售商造成影响。再次,对于低利润产品,高价后悔加剧了(缺货后悔缓解了)策略型消费者行为的负影响;对于高利润产品,后悔行为不影响策略型消费者行为的负影响。最后,当零售商拥有全价决策权时,零售商总是能够利用决策全价的优势来消除高价后悔的负影响或发挥缺货后悔的正影响。