Flexible dynamic information flow control in the presence of exceptions

We show that fine-grained and coarse-grained dynamic information-flow control (IFC) systems are equally expressive. To this end, we mechanize two mostly standard languages, one with a fine-grained dynamic IFC system and the other with a coarse-grained dynamic IFC system, and prove a semantics-preserving translation from each language to the other. In addition, we derive the standard security property of non-interference of each language from that of the other, via our verified translation. This result addresses a longstanding open problem in IFC: whether coarse-grained dynamic IFC techniques are less expressive than fine-grained dynamic IFC techniques (they are not!). The translations also stand to have important implications on the usability of IFC approaches. The coarse- to fine-grained direction can be used to remove the label annotation burden that fine-grained systems impose on developers, while the fine- to coarse-grained translation shows that coarse-grained systems---which are easier to design and implement---can track information as precisely as fine-grained systems and provides an algorithm for automatically retrofitting legacy applications to run on existing coarse-grained systems.

Fine-grained information flow control (IFC) ensures confidentiality and integrity at the programming language level by ensuring that high-secrecy values do not affect low-secrecy values and that low-integrity values do not affect high-integrity values. However, prior support for fine-grained IFC is impractical: It either analyzes programs using whole-program static analysis, detecting false IFC violations; or it extends the language and compiler, thwarting adoption. Recent work called Cocoon demonstrates how to provide fine-grained IFC for Rust programs without modifying the language or compiler, but it is limited to static secrecy labels, and its case studies are limited. This paper introduces an approach called Carapace that employs Cocoon’s core approach and supports both static and dynamic IFC and supports both secrecy and integrity. We demonstrate Carapace using three case studies involving real applications and comprehensive security policies. An evaluation shows that applications can be retrofitted to use Carapace with relatively few changes, while incurring negligible run-time overhead in most cases. Carapace advances the state of the art by being the first hybrid static–dynamic IFC that works with an off-the-shelf language—Rust—and its unmodified compiler

A number of systems have been developed for dynamic information flow control (IFC). In such systems, the security policy is expressed by labeling input and output channels, it is enforced by tracking and checking labels on data. Systems have been proven to enforce some form of noninterference (NI), formalized as a property of two runs of the program. In practice, NI is too strong and it is desirable to enforce some relaxation of NI that allows downgrading under constraints that have been classified as 'what', 'where', 'who', or 'when' policies. To encompass a broad range of policies, relational logic has been proposed as a means to specify and statically enforce policy. This paper shows how relational logic policies can be dynamically checked. To do so, we provide a new account of monitoring, in which the monitor state is viewed as an abstract interpretation of sets of pairs of program runs.

Parallel manipulators with less than six degrees of freedom (DOF) have been increasingly used in high-speed hybrid machine tools. The structural features of parallel manipulators are dynamic, a characteristic that is particularly significant when these manipulators are used in high-speed machine tools. However, normal kinematic control method cannot satisfy the requirements of the control system. Many researchers use model-based dynamic control methods, such as the dynamic feedforward control method. However, these methods are rarely used in hybrid machine tools because of the complex dynamic model of the parallel manipulator. In order to study the dynamic control method of parallel manipulators, the dynamic feedforward control method is used in the dynamic control system of a 3-PSP (prismatic-spherical-prismatic) 3-DOF spatial parallel manipulator used as a spindle head in a high-speed hybrid machine tool. Using kinematic analysis as basis and the Newton-Euler method, we derive the dynamic model of the parallel manipulator. Furthermore, a model-based dynamic feedforward control system consisting of both kinematic control and dynamic control subsystems is established. The dynamic control subsystem consists of two modules. One is used to eliminate the influence of the dynamic characteristics of high-speed movement, and the other is used to eliminate the dynamic disturbances in the milling process. Finally, the simulation model of the dynamic feedforward control system of the 3-PSP parallel manipulator is constructed in Matlab/Simulink. The simulations of the control system eliminating the influence of the dynamic characteristics and dynamic disturbances are conducted. A comparative study between the simulations and the normal kinematic control method is also presented.The simulations prove that the dynamic feedforward control method effectively eliminates the influence of the dynamic disturbances and dynamic characteristics of the parallel manipulator on high-speed machine tools, and significantly improves the trajectory accuracy. This is the first attempt to introduce the dynamic feedfordward control method into the 3-PSP spatial parallel manipulator whose dynamic model is complex and provides a study basis for the real-time dynamic control of the high-speed hybrid machine tools.

Traditional web programming involves the creation of two distinct programs: a client-side front-end, a server-side back-end, and a lot of communications boilerplate. An alternative approach is to use a tierless programming model, where a single program describes the behavior of both the client and the server, and the runtime system takes care of communication. Unfortunately, this usually entails adopting a new language and thus abandoning well-worn libraries and web programming tools. In this paper, we present our ongoing work on Fission, a platform that uses dynamic tier-splitting and dynamic information flow control to transparently run a single JavaScript program across the client and server. Although static tier-splitting has been studied before, our focus on dynamic approaches presents several new challenges and opportunities. For example, Fission supports characteristic JavaScript features such as eval and sophisticated JavaScript libraries like React. Therefore, programmers can reason about the integrity and confidentiality of information while continuing to use common libraries and programming patterns. Moreover, by unifying the client and server into a single program, Fission allows language-based tools, like type systems and IDEs, to manipulate complete web applications. To illustrate, we use TypeScript to ensure that client-server communication does not go wrong.

Focusing on massive demand and high-frequency trains in urban rail transit, this paper proposes a novel joint optimization approach for train scheduling and dynamic passenger flow control strategy under oversaturated conditions to minimize the total number of waiting passengers. In view of the relationship between the number of boarding/alighting passengers and the dwell time of trains, the problem is formulated as a mixed-integer linear programming (MILP) model. This model can achieve the trade-off between the utilization of trains and passengers. The ILOG CPLEX is adopted to solve the proposed model. And a real-world case study of the Beijing Metro Line 5 is given to demonstrate the feasibility and effectiveness. Through jointly optimizing train schedule and flow control, the average boarding rate of passengers increases from 36.34% to 87.55%. The results show that the proposed flow control is effective in alleviating the oversaturated situations at platforms and trains.

The available bit rate (ABR) service category has been approved by the ATM Forum to make use of bandwidth available after satisfying the requirements of real-time services. Thus, many flow control algorithms have been proposed within the context of the ABR service. We have proposed a dynamic rate-based flow control (DRFC) scheme with the primary goal of supporting the ABR service effectively and with the additional advantage of simplicity. This paper investigates the behaviour of the DRFC scheme in conjunction with virtual source/virtual destination (VS/VD) technique. The performance is evaluated in terms of allowed cell rates, number of transmitted cells, buffer occupancy, and link utilization. It has been observed that the implementation of VS/VD technique improves the performance with minimum buffer requirements.

Language-based information-flow control (IFC) techniques often rely on special purpose, ad-hoc primitives to address different covert channels that originate in the runtime system, beyond the scope of language constructs. Since these piecemeal solutions may not compose securely, there is a need for a unified mechanism to control covert channels. As a first step towards this goal, we argue for the design of a general interface that allows programs to safely interact with the runtime system and the available computing resources. To coordinate the communication between programs and the runtime system, we propose the use of asynchronous exceptions (interrupts), which, to the best of our knowledge, have not been considered before in the context of IFC languages. Since asynchronous exceptions can be raised at any point during execution-often due to the occurrence of an external event-threads must temporarily mask them out when manipulating locks and shared data structures to avoid deadlocks and, therefore, breaking program invariants. Crucially, the naive combination of asynchronous exceptions with existing features of IFC languages (e.g., concurrency and synchronization variables) may open up new possibilities of information leakage. In this paper, we present $\mathrm {M}\mathrm {A}\mathrm {C}_{async}$, a concurrent, statically enforced IFC language that, as a novelty, features asynchronous exceptions. We show how asynchronous exceptions easily enable (out of the box) useful programming patterns like speculative execution and some degree of resource management. We prove that programs in $\mathrm {M}\mathrm {A}\mathrm {C}_{async}$ satisfy progress-sensitive non-interference and mechanize our formal claims in the Agda proof assistant.

SummaryRecent developments in the cloud technologies have motivated the migration of distributed large systems, specifically the Internet of Things to the cloud architecture. Since Internet of Things consist of a vast network and variety of objects, the cloud platform proves to be an ideal option. It is essential for the proper functioning of the Internet of Things to be able to share data among the system processes. The biggest problem faced during the transition of the IoTs to the cloud is the security of data especially while data sharing within the cloud and among its tenants. Information Flow Control mechanisms are one of the many solutions to enable a controlled sharing of data. Integration of Information Flow Control Systems to the existing architecture requires various levels of re‐engineering efforts. Moreover, most of the Information Flow Control systems focus on data flow within the cloud and neglect the security and integrity of data while it is being transferred to the cloud from various devices. This research focuses on securing the entire process of data migration to cloud from devices while the in‐cloud data flow is monitored by the Information Flow Control policies specified by the users. We have developed a prototype for the proposed model, and results are evaluated on the basis of energy consumption and execution time. As proposed model provides security services such as privacy, integrity, and authentication, hence it takes more execution time and consumes more energy as compared with the existing model.

Advanced high quality radiation therapy techniques such as IMRT require an accurate delivery of precisely modulated fluence patterns to the target volume. Intrafractional motion, however, may considerably deteriorate the accuracy of the dose delivery. To compensate for these errors, a dynamic real-time capable MLC control system was designed and implemented which compensates during the delivery for the motion and deformation of the target volume. Specialized algorithms were developed which constantly optimize the MLC aperture based on online provided target information allowing the sparing of adjacent organs-at-risk from additional dose. These algorithms were implemented in a dynamic target tracking control system for the Siemens 160 MLCTM. Experiments using different phantom setups were performed to assess and quantify the quality of the tracking technique. The results showed that 2-dimensional target motion can be compensated for with the new control system. For a clinical IMRT dose distribution, the congruence within 2 % / 2 mm with a static reference delivery was increased from 18.75% to 76.79 %. Similar improvements were achieved for the delivery of a complete IMRT treatment fraction to a moving lung phantom. However, the quality of the tracking system is limited by the system’s latency times. The experiments proved that the tracking concept, the new algorithms and the dynamic control system allow to effectively compensate for target motion in real-time. It therefore can increase the accuracy and the quality of the treatment delivery.KeywordsAdaptive RadiotherapyTumor TrackingDynamic Multileaf CollimatorMotion Management

Increases in load, increases in penetration of renewable energy, and limited investment in transmission infrastructure are fostering the need for a smarter, more dynamically controllable grid. Flexible ac transmission systems (FACTs) devices such as the UPFC and BTB are difficult to implement at transmission-level voltages due to complexity and cost. A direct-ac/ac-converter-based controllable network transformer (CNT), because of its fractional converter rating and lack of dc storage requirement, is a simpler and less expensive alternative for applications involving dynamic power flow control. Scaling of the CNT, however, is still a challenge. This paper proposes an approach for scaling the CNT to utility-level voltages and currents utilizing multilevel topologies as well as direct-ac/ac power electronic building blocks (AC-PEBBs). A comparison of various PEBB-based CNT topologies is presented via simulation and experimental results for a 13 kV, 1 MVA application.

Role-based access control (RBAC) is useful in information security. It is a super set of discretionary access control (DAC) and mandatory access control (MAC). Since DAC and MAC are useful in information flow control (which protects privacy within an application), RBAC can certainly be used in that control. Our research reveals that different control granularity is needed in different cases when controlling information flows within an application. An information flow control model should thus simultaneously offer different levels of control granularity. We designed a multipleleveled RBAC model to offer multiple levels of control granularity, in which a level of RBAC controls a level of granularity. We called the model L n RBAC (n-leveled RBAC), which offer the following features: (1) it allows different control granularity in different cases, (2) it solves the covert channel problems caused by abnormal program stopping, (3) it adapts to dynamic object state change, (4) it controls method invocation through argument sensitivity (5) it allows purpose-oriented method invocation, (6) it controls write access precisely, and (7) it avoids Trojan horses. We implemented a prototype for L n RBAC and evaluated it. This paper presents L n RBACL.

With the rapid development of information technology, the electronic information is ubiquitous, which has brought severe challenges to the transmission and reception of classified information. The common electronic information protection technology and measures were described and the primary means of foreign spy and intelligence agencies attack theft were pointed out. Through the introduction of electronic confidentiality level identifier technology and information flow control technology, the security of electronic information was achieve. Take the secret exchange of special U disk of a company in Mianyang as an example, the application of information flow control system based on electronic confidentiality level identifier in the removable storage medium to transmit information was introduced

Dynamic intelligent scheduling and control of reconfigurable parallel architectures for computer vision/image processing

Workflow process mining technology is not a tool of workflow design, but it is very useful for understanding the current business processes. Workflow process mining does well in knowledge management and decision-making support. The dynamic flow control and fuzziness make the old methods that analysis the performance of workflow not applicable. In order to solve the problem a new workflow process mining algorithm is presented.