5714667
Extending software communications architecture for QoS support in SDR signal processing
The software communications architecture (SCA) is middleware for providing component interfaces and dynamic reconfigurability to software define radio (SDR) modems and it is widely adopted by the SDR forum. Although its main application domains include real-time signal processing, SCA lacks QoS support. We thus propose a QoS-enabled extension of SCA called Q-SCA. Our extended architecture incorporates a new waveform model, extended domain profiles that describe QoS requirements, and a modified application instantiation process that supports both admission control and resource allocation. We show the viability of Q-SCA through full implementation and experiments.
14413427
Memory Footprint Reduction with Quasi-Static Shared Libraries in MMU-less Embedded Systems
Despite a rapid decrease in the price of solid state memory devices, system memory is still a very precious resource in embedded systems. The use of shared libraries is known to be effective in significantly reducing memory usage. Unfortunately, many resource-constrained embedded systems lack MMU, making it extremely difficult to support this technique. To address this problem, we propose a novel shared library scheme called the quasi-static shared library. In quasi-static shared libraries, global symbols are bound to pseudo-addresses at linking time and the actual physical addresses are bound at loading time. This scheme is made possible by emulating MMU’s memory mapping feature with a Data Section Base Register (DSBR) and a Data Section Base Table (DSBT). Quasi-static shared libraries do not require symbol tables which take up time and space at runtime. We have implemented the proposed scheme in a commercial ADSL (Asymmetric Digital Subscriber Line) home network gateway and conducted a series of experiments measuring its memory usage and performance overhead. The result is drastic: a 35% reduction in flash memory usage and a 10% reduction in RAM usage. These results were achieved with only a negligible performance penalty of less than 4%. Even though this scheme was applied to uClinux-based embedded systems, it can be used for any MMU-less real-time operating system.
14990532
Weaving Aspects into Real-Time Operating System Design Using Object-Oriented Model Transformation
Despite of the proliferation of object-oriented and component technology, their application to real-time operating systems (RTOS) has been limited since most design concerns in RTOSes crosscut software components and these are critical to deliver required performance and functionality. Aspect-Oriented Programming (AOP) is a very effective means to solve the crosscutting problem. However, we have observed the following limitations of the current AOP framework: (1) the current text-based AOP languages cannot clearly show how aspects are weaved together, (2) their granularity is too coarse to capture all aspects in an RTOS, (3) it is difficult to control the weaving process, since aspect weavers are usually hard-coded. In this paper, we propose a new AOP framework that provides (1) a graphical aspect programming environment that visualizes aspects, crosscutting classes, and method structures, (2) a new aspect model that supports a sub-method level granularity where an aspect is defined as a set of classes, and (3) an aspect weaving process specified by an object-oriented meta-model transformation. Since our aspect-oriented programming framework improves the expressiveness of the crosscutting concerns of RTOSes and automates aspect weaver generation, it can enhance RTOS customization.
18041119
Component integrity check and recovery against malicious codes
With the rise in usage of software components in distributed computing applications, the importance of safeguarding these components has assumed great significance. In trying to ensure the survivability of these components, we enable a mission-critical application to detect malicious codes in a component downloaded from a remote location and recover the original functionality of the compromised component. In our work, we use digital signatures to ensure the integrity of software components in a large distributed system. By detecting unauthorized add-ons to the original components we can ensure that only legitimate software components are allowed to execute in a protected software environment. We also explore techniques to recover the original functionality of the component under attack by removing the affected portion from the component. In this paper we introduce the system architecture and the support mechanisms for our proposed approaches
7753152
Countering Insider Threats in Personal Devices
The information age is a time when organizations are networked back and forth with multiple wires, different communication channels, many sophisticated information systems, and most importantly through the almighty Internet. This project focuses on responses that are most beneficial to organizations in regards to the internal threats. Mainly, it addresses the issues connected to the broad use of laptops, desktops, and other personal devices such as flash drives. During research there were thought different ways of mitigating the issue of insider threats. The result of this analysis is the Diamond Theory. It ties four methods of increasing the security of personal devices: software design, information retrieval, detection technology design and information policy design. All four corners of the diamond are represented by four different techniques that increase the security of personal devices and thus the defense against insider threats. These techniques are described as theoretical premises that shall be fulfilled in order to have the security raised to the maximum. Additionally, these methods are interdependent of each other and must work together to meet the overall goal of the theory.
1384536
Mining association rules with adjustable accuracy
In this paper, we devise efficient algorithms for mining association rules with adjustable accuracy. It is noted that several applications require mining the transaction data to capture the customer behavior frequently. In those applications, the efficiency of data mining could be a more important faktor t.han the requirement for complete accuracy of the mining results. Allowing imprecise results can significantly improve the data mining efficiency. In this paper, two methods for mining association rules with adjustable accuracy are developed. By dealing with the concept of sampling, both methods obtain some essential knowledge from a sampled subset first, and in light of that knowledge, perform efficient association rule mining on the entire database. A technique of relaxing the support factor based on the sampling size is devised to achieve the desired level of accuracy. These two methods differ from each other in their ways of utilizing the sampled data. Performance of these two methods is comparatively analyzed. As shown by our experimental results, the relaxation factor, as well as the sample size, can be properly adjusted so as to improve the result accuracy while minimizing the corresponding execution time, thereby allowing us to effectively achieve a design trade-off between accuracy and efficiency with two control parameters. It is shown that with the advantage of controlled sampling, the proposed methods are very flexible and efficient, and can in general lead to results of a very high degree of accuracy.
9959276
Injecting RBAC to secure a Web-based workflow system
Web-based workflow systems have recently received much attention because they can support dynamic business processes over heterogeneous computing systems. Most existing web-based workflow systems, however, provide minimal security services such as authentication of users and network security. In this paper we describes an experiment in injecting role-based access control (RBAC) into an existing web-based workflow system. Specifically, we ensure that each task can only be executed by users belonging to a specific role. In order to achieve this, we define a simplified RBAC model to meet our needs and describe the security architecture to be applied to an existing web-based workflow system. We describe our implementation using commercial off-the-shelf (COTS) technology to demonstrate the feasibility of this approach. Our implementation uses X.509v3 certificates with role attribute, and employs a user-pull style where the client requests a client certificate from the role-server and presents it to the workflow system. A major goal of our implementation is to have minimal changes to the existing web server and no changes to the browser. We also discuss alternative architecture such as server-pull with LDAP (Lightweight Directory Access Protocol).
10180647
Specularity elimination in range sensing for accurate 3D modeling of specular objects
We present a novel range sensing method that is capable of constructing accurate 3D models of specular objects. Our method utilizes a new range imaging concept called multipeak range imaging, which accounts for the effects of mutual reflections. False measurements generated by mutual reflections are then eliminated by applying a series of constraint tests based on local smoothness, global coordinate consistency and visibility consistency. We show the usefulness of our method by applying the method to three real objects with specular surfaces. The ground truth data for those three objects were also acquired in order to evaluate the elimination of false measurements and to justify the selection of the parameters in the constraint tests. Experimental results indicate that our method significantly improves upon the traditional methods for constructing reliable 3D models of specular objects with complex shapes.