Reconstructing the environment in cyber space by sensory data is a fundamental operation for understanding physical world depth. A lot of basic scientific work (e.g., nature discovery, organic evolution) heavily relies on accuracy reconstruction. However, loss wireless sensor networks common and has its special patterns due to noise, collision, unreliable link, unexpected damage, which greatly reduces Existing interpolation methods do not consider these thus fail provide satisfactory when...

Distributed storage systems are increasingly transitioning to the use of erasure codes since they offer higher reliability at significantly lower costs than data replication. However, these tradeoff recovery performance as require multiple disk reads and network transfers for reconstructing an unavailable block. As a result, most existing code either optimized overhead or performance.In this paper, we present HACFS, new erasure-coded system that instead uses two different dynamically adapts...

Reconstructing the environment by sensory data is a fundamental operation for understanding physical world in depth. A lot of basic scientific work (e.g., nature discovery, organic evolution) heavily relies on accuracy reconstruction. However, loss wireless sensor networks common and has its special patterns due to noise, collision, unreliable link, unexpected damage, which greatly reduces reconstruction accuracy. Existing interpolation methods do not consider these thus fail provide...

Mobile applications can access both sensitive personal data and the network, giving rise to threats of leaks. App auditing is a fundamental program analysis task reveal such Currently, static de facto technique which exhaustively examines all flows pinpoints problematic ones. However, generates false alarms for being over-estimated requires minutes or even hours examine real app. These shortcomings greatly limit usability automatic app auditing. To overcome these limitations, we design...

System virtualization, which provides good isolation, is now widely used in server consolidation. Meanwhile, one of the hot topics this field to extend virtualization for embedded systems. However, current popular platforms do not support real-time operating systems such as Linux well because platform ware, will bring low-performance I/O and high scheduling latency. The goal paper optimize Xen be system friendly. We improve two aspects platform. First, we xen scheduler manage latency...

Document storage in the cloud infrastructure is rapidly gaining popularity throughout world. However, it poses risks to consumers unless data are encrypted for security. Encrypted should be effectively searchable and retrievable without any privacy leaks, particularly mobile client. Although recent research has solved many security issues, architecture cannot applied on devices directly under environment. This due challenges imposed by wireless networks, such as latency sensitivity, poor...

For mobile apps, user-perceived delays are critical for user satisfaction. According to our measurement, long commonly caused by network and storage I/O operations while short mainly UI rendering. Short not uncommon, which account 55.3% in measurement cases. Previous app performance studies have largely focused on but the understanding of rendering impact is limited. In this work, we propose DRAW, a system that performs two analyses help developers pinpoint problems resolve delays. The first...

In multi-hop wireless ad-hoc networks, packet delivery delay is one of the most important performance metrics. While a lot research efforts have been spent on measuring and optimizing end-to-end performance, there usually lack accurate lightweight methods for decomposing into per-hop each packet. Knowledge per-packet can greatly improve network visibility facilitate measurement management. this paper, we propose Domo, passive, tomography approach to hop. The basic idea formulate problem set...

It is crucial to minimize virtualization overhead for virtual machine deployment. The conventional ×86 CPU incapable of classical trap-and-emulate virtualization, leading that paravirtualization was the optimal strategy formerly. Since architectural extensions are introduced support hardware assisted becomes a competitive alternative method. Hardware superior in and memory yet still valuable some aspects as it capable shortening disposal path I/O virtualization. Thus we propose hybrid which...

Mobile advertising plays a vital role in the mobile app ecosystem. A major threat to sustainability of this ecosystem is click fraud, i.e., ad clicks performed by malicious code or automatic bot problems. Existing fraud detection approaches focus on analyzing requests at server side. However, such may suffer from high false negatives since can be easily circumvented, e.g., when are behind proxies globally distributed. In paper, we present AdSherlock, an efficient and deployable approach...

New media and communication technologies like mobile devices are nowadays widely used everywhere for providing rich functionalities highly personalized services. However, using such a device in driving environment is still very inconvenient unsafe to be controlled by the driver. The touchscreen operations one major obstacle since multi-touchscreen optimized hand-held usage scenarios. To overcome this limitation, we propose replace some most touch with gesture controls environment. Gesture...

Mobile operating systems embrace new mechanisms that reduce energy consumption for common usage scenarios. The background app design is a representative implemented in all major mobile OSes. OS keeps apps are not currently interacting with the user memory to avoid repeated loading. This mechanism improves responsiveness and reduces when switches apps. However, we demonstrate application errors, particular leaks cause system pressure, can easily cripple this mechanism. In paper, conduct...

Video streaming systems such as YouTube and Netflix are usually supported by the content delivery networks datacenters that can consume many megawatts of power. Most existing works independently study issues improving quality experience (QoE) for viewers reducing cost emissions associated with enormous energy usage datacenters. By contrast, this paper addresses them both, jointly optimizes QoE, intelligently allocating datacenter bandwidth among different client groups. Specially, we propose...

The past decade has witnessed a tremendous growth in the variety and complexity of mobile applications (apps). Although considerable amount efforts have been spent to improve app performance, smartphones nowadays still face many performance challenges. We discover that resource contention multiple running apps, caused by bottleneck(s), is key factor affects smartphone performance. In this paper, we present APB, an Automatic tool detects Performance issues Bottleneck(s) on commodity Android...

Numerous operating systems have been designed to manage and control system resources with large complicated features, so they need high security protection. However, previous applications can not provide adequate protection due the untrusted execution environment. Furthermore, these strategies cannot support a universal cross-platform requirements. This paper presents VASP, hypervisor based monitor which allows trusted environment various malicious behaviors in system. is achieved by taking...

Debugging, albeit useful for software development, is also a double-edge sword since it could be exploited by malicious attackers. This paper analyzes the prevailing debuggers and classifies them into 4 categories based on debugging mechanism. Furthermore, as an opposite, we list 13 typical anti-debugging strategies adopted in Windows. These methods intercept specific execution points which expose diagnostic behavior of debuggers.

Mobile apps are born to work in an environment with ever-changing network connectivity, random hardware interruption, unanticipated task switches, etc. However, such interference cases often oblivious traditional mobile testing but happen frequently and sophisticatedly the field, causing various robustness, responsiveness consistency problems. In this paper, we propose JazzDroid introduce testing. adopts a gray-box approach instrument at binary level that logic is inlined app execution can...

Modern RESTful services expose APIs to integrate with diversified applications. Most API parameters are weakly typed, which greatly increases the possible input value space. Weakly-typed pose difficulties for automated testing tools generate effective test cases reveal web service defects related parameter validation. We call this phenomenon type collapse problem. To remedy problem, we introduce FET (Format-encoded Type) techniques, including FET, lattice, and inference model fine-grained...

App responsiveness is the most intuitive interpretation of app performance from user's perspective. Traditional profilers only focus on one kind program activities (e.g., CPU profiling), while cause for slow diverse or even due to joint effect multiple kinds. Also, various test configurations, such as device hardware and wireless connectivity can have dramatic impact particular indirectly affect responsiveness. Conventional mobile testing lacks mechanisms reveal configuration-sensitive bugs....

Social networks help to bond people who share similar interests all over the world. As a complement, Facebook "Like" button is an efficient tool that bonds with online information. People click on express their fondness of particular piece information and in turn tend visit webpages high count. The important fact Like count it reflects number actual users "liked" this However, according our study, one can easily exploit defects counterfeit We provide proof-of-concept implementation these...