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.

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.

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.

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。

寻找消失的遗产:基于多重证据的湮废园林复原研究方法

【目的】湮废园林涉及历史上因各种原因消失的园林,以及现存园林经重大改变前的早期风貌。中国园林早期的历史风貌是中国风景园林遗产的重要组成部分,其复原研究是风景园林历史理论研究的核心领域。【方法】探索多重证据在湮废园林复原研究中的运用:首先将复原证据分为现场实存、遗址考古、诗文文献、绘画图像、口述证言、相关实存和造园理论7种类型,按性质可分为实物证据、文献证据和言辞证据,按关联性可分为直接证据和间接证据;进而逐一辨析7类证据的特点,结合实例分析它们在复原研究中的应用。【结果】指出湮废园林复原过程中应注意证据的可用性与可靠性,关注证据之间的相互印证和证据的持续更新。【结论】尝试建立一套依据可靠、过程可操作的研究方法,为湮废园林复原研究提供方法论的参考。

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.

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.

易腐浆果类可食涂膜保鲜技术研究进展

浆果类水果皮薄多汁、质地柔软,易受到机械损伤与病原菌侵染,是最难保存的果蔬种类。可食涂膜保鲜具有安全可食、隔绝保护、抑菌杀菌及增加营养价值等特点。概述了易腐浆果常用的保鲜技术,重点梳理了可食性涂膜最新研究结果,以期为易腐浆果保鲜提供参考。

热解温度对不同种类易腐垃圾生物质炭理化特性的影响

随着垃圾分类政策的推行,易腐垃圾减量化、无害化、资源化处理越来越重要,热解炭化是一条具有环境效益和经济效益的处理途径.本研究利用扫描电镜、X射线衍射、傅里叶红外光谱及比表面积分析等表征方法,系统地分析了热解温度对6种易腐垃圾生物质炭(甘蔗皮炭、豌豆荚炭、橘子皮炭、柚子皮炭、桂圆皮炭和厨余垃圾炭)理化特性的影响.结果表明:①热解温度是影响生物质炭理化特性的关键因子,随热解温度的升高,易腐垃圾炭产率降低,灰分含量、pH和EC值增大,表面-OH、C-H、C=O、C=C和C-O-C等官能团含量减少,CaC_(2)O_(4)和K_(2)C_(2)O_(4)等草酸盐逐步分解为CaCO_(3)和K_(2)CO_(3).当热解温度为650℃时,厨余垃圾炭的产率、灰分含量、pH分别为41.7%、57.4%、9.8.②生物质原料种类是影响生物质炭理化特性的另一关键因子,不同种类的生物质炭表面元素含量、比表面积和形貌结构等参数均不相同,厨余垃圾炭的产率、灰分含量、表面钠元素和钙元素含量明显高于其他易腐垃圾炭.③易腐垃圾热解炭化主要包括脱水、脱羧、聚合、芳构化等过程,采用热解炭化技术处理易腐垃圾的毛利润约为630元/t,既具有环境效益又具有经济效益.上述研究结果为拓宽易腐垃圾炭资源化利用途径提供了基础数据,可有效助力无废城市建设.

双渠道供应链下易腐品的库存和定价决策

以现实易腐产品供应链为背景,研究单一零售商和单一供应商组成的双渠道供应链模型,即供应商可通过直接在线渠道和间接零售渠道销售易腐产品,除了产品数量下降外,产品质量也会随着时间的推移而下降,同时,产品质量的下降会影响零售渠道的需求率。分别建立集中式和分散式两类模型,并提出相应算法求解最佳价格、订购频率和订购周期等。结果显示,分散式的供应链不仅会侵蚀两家公司的利润,并且产品的浪费率也较高。通过采用收入分享和二部定价法的方式能够协调供应链,减少供应链的总浪费率。同时,随着产品劣化率的提高,两家公司会更倾向于进行供应链协调,协调合同对零售商利润的提升更为显著。在模型扩展部分考虑直接渠道的交货时间,结果表明,分散式模型的供应商会投入更多资金以缩短交货时间。

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.