最近網路中心系統的發展趨勢促進了訊息管理能力的發展，確保在規定的時間範圍內有效地在正確的地點提供正確的訊息，以滿足許多不同環境中的服務品質（QoS）要求。數據分發服務中間軟體提供了一種解決方案，它使用服務品質（QoS）策略作為一組特性來驅動給定的行為，使服務能夠滿足這些要求。QoS策略具有廣泛且可以應用於在系統內互動的實體對象，如發布者、訂閱者和主題等的屬性，舉例來說，總共有11個QoS策略適用於主題實體，但很難找到這些策略及其適當價值的最佳組合。在本文中，我們提出了一種通過僅使用適用於主題實體的QoS策略來最佳化特定系統設計性能（丟失率和延遲）的方法。我們使用相關分析和我們實驗中收集的數據集的QoS策略規範來找出每個QoS策略對性能的影響。最後的結果我們發現，能夠最佳化特定系統設計的丟失率性能的QoS策略組合是可靠性（Reliability）和持久性（Durability）QoS，而提高延遲性能的是截止（Deadline）QoS。;Recent trends in net-centric systems motivate the development of information management capabilities that ensure the right information is delivered at the right place efficiently within specified time-range to satisfy the quality of service (QoS) requirements in many different environments. Data Distribution Service middleware offers a solution with the use of Quality of Service (QoS) Policies as a set of characters that drive a given behavior of the service so it may able to fulfill those requirements. QoS Policies has a wide range of attributes that can be applied to the Entity objects interacting within the system such as publisher, subscriber, topic etc. for example there are a total of 11 QoS Policies applicable to the Topic entity, however, it is difficult to find an optimal combination of these policies and their appropriate value. In this thesis we propose a way to optimize the performance (loss rate and latency) of a particular system design by using only the QoS Policy applicable to Topic entity. We use correlation analysis and the specification of QoS Policies for the collected dataset from our experiment to find the impact for each QoS policy toward the performance. The final result we found out that the combination of QoS Policies for a particular system design that able to optimize the performance of loss rate are Reliability & Durability QoS while to improve the performance of latency is Deadline QoS.
