15361115
The UCONABC usage control model
In this paper, we introduce the family of UCONABC models for usage control (UCON), which integrate Authorizations (A), oBligations (B), and Conditions (C). We call these core models because they address the essence of UCON, leaving administration, delegation, and other important but second-order issues for later work. The term usage control is a generalization of access control to cover authorizations, obligations, conditions, continuity (ongoing controls), and mutability. Traditionally, access control has dealt only with authorization decisions on users' access to target resources. Obligations are requirements that have to be fulfilled by obligation subjects for allowing access. Conditions are subject and object independent environmental or system requirements that have to be satisfied for access. In today's highly dynamic, distributed environment, obligations and conditions are also crucial decision factors for richer and finer controls on usage of digital resources. Although they have been discussed occasionally in recent literature, most authors have been motivated from specific target problems and thereby limited in their approaches. The UCONABC model integrates these diverse concepts in a unified framework. Traditional authorization decisions are generally made at the time of requests but hardly recognize ongoing controls for relatively long-lived access or for immediate revocation. Moreover, mutability issues that deal with updates on related subject or object attributes as a consequence of access have not been systematically studied.Unlike other studies that have targeted on specific problems or issues, the UCONABC model seeks to enrich and refine the access control discipline in its definition and scope. UCONABC covers traditional access controls such as mandatory, discretionary, and role-based access control. Digital rights management and other modern access controls are also covered. UCONABC lays the foundation for next generation access controls that are required for today's real-world information and systems security. This paper articulates the core of this new area of UCON and develops several detailed models.
9807251
Originator Control in Usage Control
Originator Control is an access control policy that requires recipients to gain originator’s approval for redissemination of disseminated digital object. Originator control policies are one of the generic and key concerns of usage control. Usage control is an emerging concept which encompasses traditional access control and digital rights management solutions. However, current commercial Digital Rights Management (DRM) solutions lack enforcement of access control policies such as role-based access control (RBAC), mandatory access control (MAC), discretionary access control (DAC) and originator control because their control of access to digital object is mainly based on payment. In this paper, we attempt to combine originator control policies and usage control. Then we show how this can extend traditional originator control solutions to enforce access control policies even outside of a local control environment where a central control authority is not available. License and ticket concepts are proposed and used for originator control in usage control. Also, we define seven different solution approaches to deal with various dissemination situations. In addition, we discuss some published DRM solutions and relate these to our solution approaches.
15806644
Attribute Mutability in Usage Control
The notion of Usage Control (UCON) has been introduced recently to extend traditional access controls by including three decision factors called authorizations, obligations, and conditions. Usage control also recognize two important decision properties of continuity and mutability. In access control literature, an authorization decision is commonly made by utilizing some form of subject and object attributes. Identities, security labels and roles are some examples of attributes. Traditionally these attributes are assigned to subjects and objects by a security officer and can be modified only by administrative actions. However, in modern information systems these attributes are often required to be changed as a side effect of subject’s usage on object. This requirement of updates has been recognized and defined as mutability property in usage control. In this paper, we discuss issues of this attribute mutability and show how usage control can apply this mutability property in various traditional and modern access control policies.
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.
17152003
WLAN Security: Current and Future
Wireless LAN deployment improves users' mobility, but it also brings a range of security issues that affect emerging standards and related technologies.
13229931
A Haptic Teleoperation Approach Based on Contact Force Control
This paper presents a new teleoperation approach using a virtual spring, and local contact force control on the slave robot. The operational space framework provides the control structure needed to achieve decoupled task dynamics. A virtual spring connects the master and slave systems and a closed-loop force controller compensates for the dynamics of the slave system, rendering transparent the effector of the slave robotic system. The active force control approach allows the desired motion and contact forces to be combined in a single force command. The required performance and robustness of force control are achieved by a full state reconstruction using a modified Kalman estimator, which addresses disturbances and modeling uncertainties. The performance of both telepresence and force control are further improved by on-line stiffness estimation of the object in contact with the effector. The redundancy of the mobile manipulation system is addressed through a decoupled decomposition of task and posture dynamics.
12592675
A New Approach for Active Stereo Camera Calibration
By active stereo we mean a stereo vision system that allows for independent panning and tilting for each of the two cameras. One advantage of active stereo in relation to regular stereo is the former's wider effective field of view; if an object is too close to the camera baseline, the depth to the object can still be estimated accurately by panning the cameras appropriately. Another advantage of active stereo is that it can yield a larger number of depth measurements simultaneously for each position of the platform on which the camera system is mounted. Panning and tilting over a large angular range, while being the main reason for the advantages of active stereo, also make it more challenging to calibrate such systems. For a calibration procedure to be effective for active stereo, the estimated parameters must be valid over the entire range of the pan and tilt angles. This paper presents a new approach to the calibration of such vision systems. Our method is based on the rationale that an active stereo calibration procedure must explicitly estimate the locations and the orientations of the pan and tilt rotating axes for the cameras through a closed-form solution. When these estimates for the axes are combined with the homogeneous transform relationships that link the various coordinate frames, we end with a calibration that is valid over a large variation in the pan and tilt angles.
13486405
Static vs. dynamic recovery models for survivable distributed systems
The need for survivability is more pressing for mission-critical systems, especially when they are integrated with other COTS products or services. As information systems became more complex and the interdependence of these systems became higher, the survivability picture became more complicated. In this paper, we introduce two basic models with respect to static and dynamic models, where each model has restart and continue modes. We describe each approach and compare the trade-offs in terms of simplicity, resource efficiency, adaptation, service downtime, immunization, and robustness. Later, we introduce a hybrid model by combining these two basic models. Our approaches are transparent to the client side and can be applied to existing distributed systems by extending the server side with the components necessary for the schemes.
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.