In this study, a cloud service optimization model is presented for resource adaptation control, in which the cost to the user, various levels of virtual machine efficacy, and rental price are considered. A cloud service middleware (CSM) that supports flexible web services by using heterogeneous platforms is proposed.
Design/methodology/approach – Developers can conveniently register web services and deploy them to the middleware. The middleware provides a two-phase energy-minimization load balance (EM-LB) mechanism, which considers the temperature of the machine, its power consumption, and the computing resources of virtual machines. The EM-LB mechanism maintains a safe temperature threshold and minimizes power usage, thereby reducing hotspots and conserving energy. Furthermore, the EM-LB mechanism efficiently schedules the operations of virtual machines and provides a high-quality service.
Findings – The proposed EM-LB mechanism is implemented to prove the feasibility of the model. In experimental environments, the results show that the EM-LB model can provide cloud computing services with lower energy consumption, higher host availability and colder temperature of machines. Furthermore, the resource reallocation can be performed to provide these services with lower costs in the second phase.
Originality/value – This study proposes a CSM platform with the proposed two-phase EM-LB mechanism to provide cloud computing services with lower energy consumption, higher host availability, colder temperature of machines, and lower costs.

針對雲端計算之
1.負載平衡機制 (Load-Balance)
2.能源耗損最小化控制 (Energy Consumption Minimization)  
3.服務最佳化模型(Service Optimization Model)

雲端服務類型常會分成以基礎建設為服務(Infrastructure as a Service, IaaS)、以平台為服務(Platform as a Service, PaaS)以及以軟體為服務(Software as a Service, SaaS)，PaaS雖然市場規模最小，但卻可創造一群合作夥伴及開發人員，並提供廠商及客戶更簡易開發新應用以及客製化現有應用的方式，目前已有高達150多種PaaS產品存在市場上，因此是競爭十分激烈的領域。在中介平台軟體技術中以服務導向架構(Service Oriented Architecture, SOA)最為熱門，服務導向架構以服務(Service)為基本單位，採用開放式資料標準格式(如：HTTP、XML等)，定義服務標準介面(Interface)透過Web通訊協定進行訊息或資料的交換，但傳統中介平台架構無法輕易依據市場上變動的需求進行伺服器資源調整，可能造成資源的浪費或不足，並且不易保證一定的服務品質(Quality of Service, QoS)，本研究設計一雲端服務中介平台，提供服務開發者整合註冊及部署介面，利用負載平衡機制，有效分散使用者服務請求，減少伺服器熱點的產生，以維持系統與服務穩定，減少能源的消耗，並藉由雲端服務最佳化模型，依據使用者需求的變動進行資源調整。