System management is becoming increasingly complex and brings high costs, especially with the advent of cloud computing. Cloud computing involves numerous platforms often of virtual machines (VMs) and middleware has to be managed to make the whole system work cost-effectively after an application is deployed. In order to reduce management costs, in particular for the manual activities, many computer programs have been developed remove or reduce the complexity and difficulty of system mamnagement. These programs are usually hard-coded in languages like Java and C++, which bring enough capability and flexibility but also cause high programming effort and cost. This paper proposes an architecture for developing management programs in a simple but powerful way. First of all, the manageability of a given platform (via APIs, configuration files, and scripts) is abstracted as a runtime model of the platform’s software architecture, which can automatically and immediately propagate any observable runtime changes of the target platforms to the corresponding architecture models, and vice versa. The management programs are developed using modeling languages, instead of those relatively low-level programming languages. Architecture-level management programs bring many advantages related to performance, interoperability, reusability, and simplicity. An experiment on a real-world cloud deployment and comparisonwith traditional programming language approaches demonstrate the feasibility, effectiveness, and benefits of the new model based approach for management program development.

Access control is a common concern in most software applications. In component-based systems, although developers can implement access control requirements (ACRs) by simply declaring role-based access control configurations (ACCs) of components, it is still difficult for them to define and evolve ACCs accurately implementing ACRs due to the gap between the complex high-level ACRs and the voluminous ACCs enforced by underlying middleware platforms, and the ad hoc mistakes of human. This paper introduces and clarifies the concept of accuracy of ACCs relative to ACRs, and presents a set of metrics and algorithms which can be used to automatically evaluate and improve accuracy of ACCs by evaluating and reconfiguring the software architecture with ACCs. We apply our achievements in a composed e-shop application.

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Mobile devices with 3G/4G networking often waste energy in the so-called “tail time” during which the radio is kept on even though no communication is occurring. Prior work has proposed policies to reduce this energy waste by batching network requests. However, this work is challenging to apply in practice due to a lack of mechanisms. In response, we have developed DelayDroid, a framework that allows a developer to add the needed policy to existing, unmodified Android applications (apps) with no human effort as well as no SDK/OS changes. This allows such prior work (as well as our own policies) to be readily deployed and evaluated. The DelayDroid compile-time uses static analysis and bytecode refactoring to identify method calls that send network requests and modify such calls to detour them to the DelayDroid run-time. The run-time then applies a policy to batch them, avoiding the tail time energy waste. DelayDroid also includes a cross-app communication mechanism that supports policies that optimize across multiple apps running together, and we propose a policy that does so. We evaluated the correctness and universality of the DelayDroid mechanisms on 14 popular Android apps chosen from the Google App Store. To evaluate our proposed policy, we studied three DelayDroid-enabled apps (weather forecasting, email client, and news client) running together, finding that the DelayDroid mechanisms combined with our policy can reduce 3G/4G tail time energy waste by 36%.

Redundant transfer of resources is a critical issue for compromising the performance of mobile Web applications (a.k.a., apps) in terms of data traffic, load time, and even energy consumption. Evidence demonstrates that the current cache mechanisms are far from satisfactory. With lessons learned from how native apps manage their resources, in this article, we present the ReWAP approach to fundamentally reducing redundant transfers by restructuring the resource loading of mobile Web apps. ReWAP is based on an efficient resource-packaging mechanism where stable resources are encapsulated and maintained into a package, and such a package shall be loaded always from the local storage and updated by explicitly refreshing. By retrieving and analyzing the update of resources, ReWAP maintains resource packages that can accurately identify which resources can be loaded from the local storage for a considerably long period. ReWAP also provides a wrapper for mobile Web apps to enable loading and updating resource packages in the local storage as well as loading resources from resource packages. ReWAP can be easily and seamlessly deployed into existing mobile Web architectures with minimal modifications, and is transparent to end-users. We evaluate ReWAP based on continuous 15day access traces of 50 mobile Web apps randomly chosen from Alexa top 500 ranking list. Compared to the original mobile Web apps with cache enabled, ReWAP can significantly reduce the data traffic, with the median saving up to 51 percent. In addition, ReWAP can incur only very minor runtime overhead of the client-side browsers and thus does not compromise user experiences.