全溫層物流營運規劃之研究

Abstract

近年來，隨著宅配服務與電子商務之興起，配送物品朝著多樣少量與多溫層的方向 發展，該趨勢亦使物流業者對多溫共配之相關課題日益重視，除在運送貨物品質之控管 問題外，全溫層物流之網路設計、技術選擇、車隊規劃、裝載計畫與服務頻次等營運規 劃問題都是未來發展所面臨重大的挑戰之ㄧ。有關全溫層物流的文獻相當少見，其中以 全溫層物流新技術的開發與應用佔大部分，目前常見之配送方式大致可分為單溫配送與 多溫共配兩種；在運輸營運規劃之相關文獻中，鮮少針對物流技術與多溫層貨物之運輸 營運規劃課題進行探討；而在配送策略相關文獻中，則多以一般與單溫低溫貨物之配送 為研究對象，少就多溫共配之議題進行深入研究；另在航空貨運之相關文獻中，則少針 對各溫層貨物特性構建數學模式分析航空公司於提供差異化運送策略之研究。故本研究 擬構建一系列模式探討全溫層物流在陸運與空運上之相關營運規劃議題。 本研究擬針對目前物流業朝向全溫層物流發展之趨勢，所衍生的各議題進行研究， 包含以陸運與空運配送之全溫層物流營運規劃問題，分別以陸運之內部營運網路、外部 營運網路與航空營運網路做分析，並分為三年期研究計畫做深入探討。第一年期計畫擬 針對陸運之內部配送營運規劃相關課題進行探討，考慮各溫層貨物需求分佈與時效性之 差異下，以業者追求總運送成本最小化之內部營運網路規劃內容，並採以兩階段求解； 第一階段為中長期策略規劃，規劃內容有：車輛路徑（車輛數）、營運網路適合使用之 技術類型、車輛型式等，該問題型式為線性整數規劃問題，可以分支定限法（Branch and Bound）求解最佳解；第二階段為中期戰術規劃，根據第一階段所得到之規劃內容與放 鬆部分變數的整數條件，求解貨物路徑、車輛頻次與運具大小等規劃內容，此問題型式 為線性規劃問題，可在有限時間內求解完成。第二年期計畫擬針對陸運之外部配送營運 規劃相關課題進行探討，針對抽換式蓄冷保溫箱多溫共配技術，考量商品因應動態需求 變化與時間相依之需求特性下，以業者利潤最大化為目標建構數學規劃式，規劃能因應 時間、空間相依需求特性與同時考量供給與需求面之最適服務週期與運費之策略。第三 年期計畫擬針對航空配送營運規劃相關課題進行探討，考慮貨主在選擇運送策略時以運 輸成本與存貨成本的總和成本最小化為選擇運送策略的依據，進一步並構建航空公司的 運送策略成本函數，包含航機相關的運送成本、貨量相關的處理成本、營運快速運送策 略需提供的保溫設備成本及額外增加的人工成本等，以規劃不同運送策略的運送頻次與 運費、各溫層的單位費率等，並在供需互動架構下，分析貨主運送不同溫層貨物的需求 特性，如：貨物價值、運送距離、託運貨量及不同貨品的腐敗特性等因素，對航空公司 規劃快速運送策略的影響，並求解航空公司於提供不同運送策略的最適頻次、運費及各 溫層之單位費率。 最後，本研究擬針對全溫層物流與航空貨運業者進行範例分析，以驗證本研究不同 年期所構建的模式在實際應用上的可行性與模式發展之潛力。本研究在學術貢獻上可補 過去文獻之不足，亦期能提供相關問題之其他學術研究之參考。而在實務上，期能提供 全溫層物流業者與航空貨運業者更具因應環境改變與決策彈性之規劃參考依據。

The continued growth of demand on multi-temperature products and wide spread of timely customer demand has greatly contributed to the challenge of logistics carriers. Under the multi-temperature joint distribution system and various deterioration of products, how to design a comprehensive hub and spoke network and service strategy to serve consumers with distinct dynamic demand has become an important issue for a multi-temperature joint distribution carrier to achieve cost effective while maintain the maximized customer satisfaction. In practice, the categories of the distribution system include regular and multi-temperature product distribution. Some studies have analyzed the problems on distributing regular and/or specific-temperature products but few of them focused on multi-temperature products. Past studies have largely discussed the development of techniques applied in the multi-temperature joint distribution system. Moreover, in the field of physical distribution problems, the multi-temperature joint distribution problem combined with techniques employed and dynamic demand are seldom discussed. Furthermore, there are no current studies formulating mathematical models and aiming to discuss the discriminatory delivery service strategy for air cargo carrier in response to demand-supply interaction and timely demand of multi-temperature products. The proposed study attempts to explore above issues by formulating a series of models. This study attempts to propose operational planning for multi-temperature joint distribution system under dynamic demand. Then, the study develops a series of models on analyzing land and air cargo carriers』 operational decisions, such as temperature-controlled technique, the size and types of vehicle fleet, vehicle routing, delivery and shipping service strategies, shipping charges for standard and special services by applying network models, heuristics, analytical models and mathematical programming models. The three-year study includes three topics. In the first year, the hub-and-spoke network design problem in response to time-dependent and multi-temperature demand for multi-temperature joint distribution carriers is studied. The hub-and-spoke network design problem in the study solves both strategic and operational decisions by employing two stage heuristic methods. The prior planning problem solves the number of each type of vehicles, types of techniques used in the network and vehicle routing by means of branch-and-bound methods. According to the results obtained from the first stage and relaxations, the linear programming problem in the second stage can be solved in a reasonable time, to determine the product delivery routes, shipping frequency and the size of vehicles. In the second year, this study attempts to optimize a delivery service strategy for multi-temperature joint distribution carries by considering dynamic, spatial and time-dependent demand, demand-supply interaction, and deterioration characteristics of various products. First, this study employs the analytical method to formulate retailer demand function by considering the remaining shelf life of products and shipping fee, where the remaining shelf life depends on the deterioration of products, lead time and delivery time. The costs considered are transportation cost, inventory cost, penalty cost for violating customers』 delivery time-windows and energy cost for maintaining the optimal temperature for various products in the delivery process. Furthermore, this study develops a mathematical programming model for determining the optimal delivery service cycles and charges for shipping differential temperature products, taking into account demand-supply interaction. In the third year, this study not only investigates the relationship between the demand and service strategies of express and standard air service but also proposes a mathematical programming modal on determining flight frequency and shipping charges of various temperature products for air cargo carriers. This study first formulates a shippers』 shipping alternative choice model. Shippers』 choices between express and standard shipping services are dependent on demand factors such as cargo value, amount and temperature-controlled requirement as well as supply attributes such as shipping charge, flight frequency and express handling and custom service. Then, this study formulates air carrier』s cost functions including transportation cost, handling cost and additional cost for temperature controlled equipment with respect to express and standard shipping services. Furthermore, this study formulates a mathematical programming model to determine the optimal flight frequency for express and standard services and surcharge for different temperature products with demand-supply interaction by maximizing the airline』s total profit. Finally, a series of case studies about the selected multi-temperature joint distribution carrier and air cargo carriers will be provided to illustrate the results and the application of the developed models. Consequently, the expected results of the developed models can provide basis on studies regarding distribution routes, product delivery strategy and airline service strategy in the context of multi-temperature joint distribution problems. Furthermore, the results may shed light on multi-temperature joint distribution carrier and airlines regarding their decision-making on operating strategy, marketing, delivery service strategy in response to the determination nature of multi-temperature products and timely delivery requirement of customers.