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.
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.
404376
Power-aware deterministic block allocation for low-power way-selective cache structure
This paper proposes a power-aware cache block allocation algorithm for the way-selective set-associative cache on embedded systems to reduce energy consumption without additional delay or performance degradation. For this goal, way selection logic and specialized replacement policy are designed to enable only one way of set-associative cache as in the direct-mapped cache. Overall cache access time becomes almost the same as that of a conventional set associative cache with accessing additional way selection logic. Because data array can be accessed without waiting for tag comparison, multiplexer delay can be removed totally. The simulation result shows that the proposed architecture can reduce a per access power consumption by 59% over conventional set-associative caches with average 0.06% of negligible performance loss.
42838112
Trusted Identity and Session Management Using Secure Cookies
The concept of federated identity management is increasingly coming to use in order to bring Service Providers closer to customers. Users are being provided an enriched experience while carrying out business on the Web at reduced overhead and improved customer service. The idea of maintaining a single profile and gaining access to multiple services has been accepted well by the customers. However, the benefits of breaking through just one set of credentials to gain access to multiple services has made the concept of Federated Identity Management of high interest to malicious users. In this paper, we analyze the structure of a generic Federated Identity Management System and explore the .NET Passport framework in depth. We explore the current security mechanisms adopted by the .NET Passport and identify potential security weaknesses. We then propose our new approaches to enhance the security services in .NET Passport by using Secure Cookies. Our approaches are transparent to and compatible with the current .NET Passport server. Finally, we prove the feasibility by implementing our ideas in a real system.
7650136
Fuzzy-logic zero-moment-point trajectory generation for reduced trunk motions of biped robots
Trunk motions are typically used in biped robots to stabilize the locomotion. However, they can be very large for some leg trajectories unless they are carefully designed. This paper proposes a fuzzy-logic zero-moment-point (ZMP) trajectory generator that would eventually reduce the swing motion of the trunk significantly even though the leg trajectory is casually designed, for example, simply to avoid obstacles. The fuzzy-logic ZMP trajectory generator uses the leg trajectory as an input. The resulting ZMP trajectory is similar to that of a human one and continuously moves forward in the direction of the locomotion. The trajectory of the trunk to stabilize the locomotion is determined by solving a differential equation with the ZMP trajectory and the leg trajectory known. The proposed scheme is simulated on a 7-DOF biped robot in the sagittal plane. The simulation results show that the ZMP trajectory generated by the proposed fuzzy-logic generator increases the stability of the locomotion and thus reduces the motion range of the trunk significantly.
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.
15933972
A logical specification for usage control
Recently presented usage control (UCON) has been considered as the next generation access control model with distinguishing properties of decision continuity and attribute mutability. Ausage control decision is determined by combining authorizations, obligations, and conditions, presented as UCONABC core models by Park and Sandhu. Based on these core aspects, we develop afirst-order logic specification of UCON with Lamport's temporallogic of actions (TLA). The building blocks of this model include:(1) a sequence of states expressed by attributes of subjects, objects, and the system, (2) state predicates on subject andobject attributes, (3) pre-defined authorization actions performed by the security system and subjects, (4) obligation actions, and(5) condition predicates on system attributes. For a UCON model we define a set of temporal logic formulas that hold as usage control policies. We show the flexibility and expressive capability of this logic model by specifying the new features and core models of UCON.