6882751
Applications of a feather-weight virtual machine
A Feather-weight Virtual Machine (FVM) is an OS-level virtualization technology that enables multiple isolated execution environments to exist on a single Windows kernel. The key design goal of FVM is efficient resource sharing among VMs so as to minimize VM startup/shutdown cost and scale to a larger number of concurrent VM instances. As a result, FVM provides an effective platform for fault-tolerant and intrusion-tolerant applications that require frequent invocation and termination of dispensable VMs. This paper presents three complete applications of the FVM technology: scalable web site testing; shared binary service for application deployment and distributed Display-Only File Server (DOFS). To identify malicious web sites that exploit browser vulnerabilities, we use a web crawler to access untrusted sites, render their pages in multiple browsers each running in a separate VM, and monitor their execution behaviors. To allow Windows-based end user machines to share binaries that are stored, managed and patched on a central location, we run shared binaries in a special VM on the end user machine whose runtime environment is imported from the central binary server. To protect confidential files in a file server against information theft by insiders, we ensure that file viewing/editing programs run in a VM, which grants file content display but prevents file content from being saved on the host machine. In this paper, we show how to customize the generic FVM framework to accommodate the needs of the three applications, and present experimental results that demonstrate their performance and effectiveness.
9176644
Automated and safe vulnerability assessment
As the number of system vulnerabilities multiplies in recent years, vulnerability assessment has emerged as a powerful system security administration tool that can identify vulnerabilities in existing systems before they are exploited. Although there are many commercial vulnerability assessment tools in the market, none of them can formally guarantee that the assessment process never compromises the computer systems being tested. This paper proposes a featherweight virtual machine (FVM) technology to address the safety issue associated with vulnerability testing. Compared with other virtual machine technologies, FVM is designed to facilitate sharing between virtual machines but still provides strong protection between them. The FVM technology allows a vulnerability assessment tool to test an exact replica of a production-mode network service, including both hardware and system software components, while guaranteeing that the production-mode network service is fully isolated from the testing process. In addition to safety, the vulnerability assessment support system described in this paper can also automate the entire process of vulnerability testing and thus for the first time makes it feasible to run vulnerability testing autonomously and frequently. Experiments on a Windows-based prototype show that Nessus assessment results against an FVM virtual machine are identical to those against a real machine. Furthermore, modifications to the file system and registry state made by vulnerability assessment runs are completely isolated from the host machine. Finally, the performance impact of vulnerability assessment runs on production network services is as low as 3%
33694964
Workflow scheduling in grids: an ant colony optimization approach
Grid applications in virtue of open service grid architecture (OGSA) are promising next-generation computation techniques. One of the most important and challenging problems about grid application is the workflow scheduling problem to achieve the users' QoS (quality of service) requirements as well as to minimize the cost. This paper proposes an ant colony optimization (ACO) algorithm to tackle this problem. Several new features are introduced to the algorithm. First, we define two kinds of pheromone and three kinds of heuristic information to guide the search direction of ants for this bi-criteria problem. Each ant uses either one from these heuristic types and pheromone types in each iteration based on the probabilities controlled by two parameters. These two parameters are adaptively adjusted in the process of the algorithm. Second, we use the information of partial solutions to modify the bias of ants so that inferior choices will be ignored. Moreover, the experimental results in 3 workflow applications under different deadline constraints show that the performance of our algorithm is very promising, for it outperforms the Deadline-MDP algorithm in most cases.
15985894
Communication models for algorithm design in networked sensor systems
Towards building a systematic methodology of algorithm design for applications of networked sensor systems, we formally define two link-wise communication models, the collision free model (CFM) and the collision aware model (CAM). While CFM provides ease of programming and analysis for high level application functionality, CAM enables more accurate performance analysis and hence more efficient algorithms through cross-layer optimization, at the cost of increased programming and analysis complexity. We use the example of optimizing a probability based broadcasting scheme under CAM to illustrate algorithm optimization. Our analytical results indicate that the optimal broadcast probability for either maximizing the reachability within a given latency constraint or minimizing the latency for a given reachability constraint decreases rapidly with node density.
8475658
Energy Minimization for Real-Time Data Gathering in Wireless Sensor Networks
This paper studies the challenging problem of energy minimization for data gathering over a multiple-sources single-sink communication substrate in wireless sensor networks by exploring the energy-latency tradeoffs using rate adaptation techniques. We consider a real-time scenario for mission-critical applications, where the data gathering must be performed within a specified latency constraint. We first propose an offline numerical optimization algorithm with performance analysis for a special case with a complete binary data gathering tree. Then, by discretizing the transmission time, we present a simple, distributed on-line protocol that relies only on the local information available at each sensor node. Extensive simulations were conducted for both long and short-range communication scenarios using two different source placement models. We used the baseline of transmitting all packets at the highest speed and shutting down the radios afterwards. Our simulation results show that compared with this baseline, up to 90% energy savings can be achieved by our techniques (both off-line and on-line), under different settings of several key system parameters
2088482
Cotton Variety Selection Model and Application Design
Choosing a  cotton variety  involves  making comparisons over many trials and across an increasingly large  number of available  varieties. To aid in this process, a computerized tool has been developed at the Texas Tech University. This tool, called COTWIZ, based on the cotton variety selection model, allows  multiple comparisons  of varieties across a number of trial locations. COTWIZ based on the cotton variety selection model and uses cotton OVT data to make  comparisons that are imported by the user.
13388104
MetaData Pro: Ontology-Based Metadata Processing for Web Resources
Metadata is the foundation of Semantic Web. The MetaData Pro project seeks to build a metadata processing platform for web resource. The system architecture has three key components– Metadata Extraction, Ontology Management, and Metadata Retrieval. The system can automatically extract metadata about web resource: if the web resource itself contains metadata, extracts them; otherwise, automatically generates the metadata for the resource according to Dublin Core by applying automatic keyword extraction and text summarization techniques. To manage the metadata, MetaData Pro integrates Protege to create domain ontology, makes use of HowNet to help ontology construction, and provides an ontology-based metadata retrieval.