在延遲容忍網路之中，資料散播是一個重要的應用，不論是廣告與新聞的發佈或是在戰場上的軍事用途溝通皆是屬於這個範疇。資料散播是一種資料導向的傳輸方式，資料導向的傳輸通常都是利用發佈訂閱系統來達成的，在發佈訂閱系統中，每個發佈出來的資料都會傳輸到有興趣的訂閱者身上。
在這篇論文之中，我們將研究如何利用發佈訂閱系統在一個資料有時效性的延遲容忍網路中做資料散播。我們認為縱使延遲容忍網路字面上是可容忍傳輸的延遲，但多數的應用中其延遲必定有一個可容忍的上限，並非無限長的。故此篇論文的目標即是將有時效性的資料在其到期前盡可能的散播出去。其困難處在於行動節點有諸多的限制，像是有限的容量、有限的頻寬以及有限的電力。如何在種種的限制下挑選恰當的資料做交換傳輸是本論文的重點。
本論文提出了一個基於製作複本的延遲容忍網路路由協定來實作發佈訂閱系統。在這系統之中，各個發行物的複本數量會依據其目前之重要性來做動態的增減，而發行物的重要性則是依據評分機制來計算的。本論文提出了四種不同的評分方式，每一種評分有其不同的考量，像是時間急迫性、資料熱門度、以及公平性。最後，我們透過模擬的結果來評估選擇這四種評分方式對於資料有時效性的發佈訂閱系統在延遲容忍網路之中會產生什麼樣的影響。

Data dissemination is an important application in DTNs. There are a large demand for data dissemination applications, such as advertisement and news publishing in urban areas or military communication in battle fields. Data-driven communication often rely on publish-subscribe paradigm which can deliver specific data to interested subscribers.
In this thesis, we study the problem of data dissemination with time-constrained through a publish-subscribe protocol in a DTN. Few researches have addressed the issue of time-constrained data dissemination in a DTN. Although a DTN is delay tolerant by definition, we consider the case in which there is an upper bound on allowable delivery latency for a publication. Our goal is to deliver as much as possible publications before they expired. However, there are few limitations for mobile nodes in a DTN, such as limited storage, limited bandwidth, and limited battery. The problem is how we choose an appropriate set of publication for exchange.
We proposed a replication–based DTN protocol for publish-subscribe which can dynamically increase or decrease the number of replica of a publication in system based on its importance. The importance is determined by the utility function. We proposed four different utility functions to rank the publications. Each utility functions is designed with different consideration in mind, such as time urgency, popularity, and fairness. We evaluate the effect of choosing different utility functions on the performance of a time-constrained publish-subscribe system in a DTN.

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