接駁式轉運中心車輛排程之研究

Coordinate Inbound and Outbound Schedules at a Cross-Docking Terminal

翁偉倫(Wei-Lun Weng)

指導教授 ： 丁慶榮

元智大學/工程學院/工業工程與管理學系/碩士(2001年)

摘要

本研究主要是探討貨物運送於接駁式轉運中心的車輛排程模式。接駁式轉運中心，又可稱為越庫作業，其定義是產品由工廠透過配送系統運至零售點，而不將產品儲存於物流中心的一種觀念，如此即可達成連續補給的快速作業；由於減少了貨物於運輸路網上的停留時間，所以貨車的整合排班對於整體轉運系統而言則顯得相當重要。
通常討論整合多重路線的貨車班表，必須要討論到各路線的發車間距。本研究所分析的路網主要分為一對一、多對一以及多對多的路網形式，藉由一對一路網所建構的基本模式來導出多重路網的數學模式；整合的策略也分為三種：未整合策略、共同間距策略以及整數比間距策略。在整體系統的成本考量上，包含非轉運成本與轉運成本，前者包含操作成本、持有成本與庫存成本，而轉運成本則是貨物因進出轉運中心之前後貨車排程無法適時銜接，所產生的額外等候成本。
本研究求解的方式主要是利用數學解析法來進行最佳解的求得。由於整數比策略的發車間距有多種組合方式，因此本研究採取合併分枝界限法的啟發式解法來尋找最優解。文中分別建立三種路網之最佳派車策略，由於共同策略與整數比策略可有效降低轉運成本，因此都比未整合策略來得好；最後並對模式中所設定的參數進行敏感度分析，結果發現1. 不同的參數環境會影響最佳決策的選擇。2. 當路網中有部份供應點與需求點的相關資料如貨物量、載運量等，與其他節點具有較大的差距時，整數比策略會有較好的表現。3. 間距與貨物量、庫存成本係數呈反比，而與其他參數呈正比。4. 由於發車間距須受限於各路線之最大間距，因此沒辦法無限制地提高發車間距，須滿足基本需求。

關鍵字

接駁式轉運 ； 間距 ； 整數比 ； 啟發式 ； 分枝界限法

並列摘要

Cross-docking is an operating strategy at flow consolidation terminals or distribution centers that moves items from the receiving dock to shipping dock directly without putting them into storage. By arranging for immediate cross-docking of incoming product, customers are able to reduce to a minimum in-transit time for their incoming product. However, cross docking requires close synchronization of all inbound and outbound shipments. This research intends to schedule the inbound and outbound vehicle routes serving a cross-docking terminal.
In this research vehicles are dispatched according to a fixed schedule (headway). Our problem is to minimize the total system costs of operating a given distribution network, including especially the value of delay time at the consolidation terminal. Three different distribution networks are discussed: one-to-one, many-to-one, and many-to-many distribution. Three strategies including uncoordinated schedules, coordinated schedules with a single common headway and integer-ratio headways are proposed. For integer-ratio headway coordination a heuristic algorithm incorporating branch-and-bound is developed to obtain the optimal (or near optimal) inbound and outbound headways as integer multiples of a base cycle. The base cycle to insure that vehicles on different routes can be operated “in phase” and arrive simultaneously (or nearly so) at the terminal.
Three illustrations representing different distribution networks are tested. The results show that as demand decreases (headway increases), coordinated schedules become desirable. They also show, for routes with significantly different characteristics (e.g., demand and route capacity), that the benefit of coordination with integer-ratio headway is large than with a single common headway.

並列關鍵字

Cross-Docking ； Headway ； Integer-Ratio ； Heuristics ； Branch-and-Bound

參考文獻

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