A compiler-hardware approach to software protection for embedded systems

Because of their rapid growth in recent years, embedded systems present a new front in vulnerability and an attractive target for attackers. Their pervasive use, including sensors and mobile devices, makes it easier for an adversary to gain physical access to facilitate both attacks and reverse engineering of the system. This paper describes a system - CODESSEAL - for software protection and evaluates its overhead. CODESSEAL aims to protect embedded systems from attackers with enough expertise and resources to capture the device and attempt to manipulate not only software, but also hardware. The protection mechanism involves both a compiler-based software tool that instruments executables and an on-chip FPGA-based hardware component that provides run-time integrity and control flow checking on the executable code. The use of reconfigurable hardware allows CODESSEAL to provide such security services as confidentiality, integrity and program-flow protection in a platform-independent manner without requiring a redesign of the processor. Similarly, the compiler instrumentation hides the security details from software developers. Software and data protection techniques are presented for our system and a performance analysis is provided using cycle accurate simulation. Our experimental results show that protecting instructions and data with a high level of security can be achieved with low performance penalty, in most cases less than 10%.     

A semantic approach to a framework for business domain software systems

In enterprise firms, enormous amounts of electronic documents are generated by business analysts and other business domain application users. Applications that use these documents are often driven by business logic that is hard-coded together with application logic. One approach to the separation of business logic from applications is to create and maintain business and information extraction rules in an external, user-friendly format. The drawback of such an externalization is that the business rules, usually, do not have machine interpretable semantics. This situation often leads to misinterpretation of domain analysis documents, which can inhibit the productivity of computer-assisted analytical work and the effectiveness of business solutions. This paper proposes an ontology and rule-based framework for the development of business domain applications, which includes semantic processing of externalized business rules and to some extent externalization of application logic. The creation of external information extraction rules by the business analyst is a cumbersome and time consuming task. In order to overcome this problem, the framework also includes a rule learning system to semi-automate the generation of information extraction rules from source documents with the help of manual annotations. The main idea behind the work presented in this paper is to re-engineer very large enterprise information systems to adapt to Semantic Web computing techniques. The work presented in this paper is inspired by an industrial project.     

A new software cache structure on Sunway TaihuLight

The Sunway TaihuLight is the first supercomputer built entirely with domestic processors in China. On Sunway Taihulight, the local data memory (LDM) of the slave core is limited, so data transmission with the main memory is frequent during calculation, and the memory access efficiency is low. On the other hand, for many scientific computing programs, how to solve the storage problem of irregular access data is the key to program optimization. Software cache (SWC) is one of the effective means to solve these problems. Based on the characteristics of Sunway TaihuLight structure and irregular access, this paper designs and implements a new software cache structure by using part of the space in LDM to simulate the cache function, which uses new cache address mapping and conflicts solution to solve high data access overhead and storage overhead in a traditional cache. At the same time, the SWC uses the register communication between the slave cores to share on the different slave core LDMs, increasing the capacity of the software cache and improving the hit rate. In addition, we adopt a double buffer strategy to access regular data in batches, which hides the communication overhead between the slave core and the main memory. The test results on the Sunway TaihuLight platform show that the software cache structure in this paper can effectively reduce the program running time, improve the software cache hit rate, and achieve a better optimization effect.

     

A user-access model-driven approach to proxy cache performance analysis

World-Wide Web usage has experienced tremendous growth in recent years. This growth has resulted in a significant increase in network and server loads that have adversely affected user response times. Among many viable and available approaches to reducing user response time, Web caching has received considerable attention. The purpose of this paper is to present an empirically derived model of Internet user-access activity, and to demonstrate its usefulness for conducting model-driven discrete simulation studies of cache performance analysis. The user-access model is shown to be a reasonable representation of Internet activity, and the user-access approach to cache performance analysis is shown to be a favorable alternative to trace-driven simulation. A report on the accuracy of the model and a summary of the findings are presented.     

A formal approach to reactive systems software: A telecommunications application in Esterel

Esterel is a formally-defined language designed for programming reactive systems; namely, those that maintain a permanent interaction with their environment. The AT&T 5ESS^® telephone switching system is an example of a reactive system. We describe an implementation in Esterel of one feature of a 5ESS switch; this implementation has been tested in the 5ESS switch simulator. Furthermore, it has been formally verified that this implementation satisfies some safety properties stated by 5ESS software development. Our experience indicates that Esterel is suitable for programming industrial-strength reactive systems, and affords significant advantages in software development over more traditional programming languages used in industrial settings.An earlier version of this paper appeared in the Proceedings of the Workshop on Industrial-Strength Formal Specification Techniques, Boca Raton, Florida, 1995.The author is currently supported by a Fulbright fellowship from Spain's Ministry of Science and Education. The work described here was performed while the author was visiting AT&T Bell Laboratories.     

Site-based approach to Web cache design

A site-based approach to Web caching tracks documents by site rather than individual document names or URLs, bringing different benefits to several different types of applications. One problem, however, is that while maintaining only site information is sufficient in many cases, it is sometimes necessary to track individual documents. For example, although the site-based least-recently-used (LRU) purging purges a whole site when a cache replacement is required, the system might still need information on individual cached documents. Currently, we are attempting to modify a real proxy server to use the site-based approach     

A transaction flow approach to software security certification for document handling systems

A security certification method is described for a document handling system for a major government organization. The security evaluation process includes identification of the exposures of the system, determination of the controls that cover those exposures, and evaluation of the appropriateness and effectiveness of the controls. Included are the details of the analysis performed and the types of results expected in that analysis, both of which constitute the basic evaluation of the document handling system. The certification analysis approach can be extended naturally to other types of computing systems.     

A general approach to avoiding two by two submatrices

Computing - A matrixC is said to avoid a set ? of matrices, if no matrix of ? can be obtained by deleting some rows and columns ofC. In this paper we consider the decision problem...     

An approach to expert control of interactive software systems

Expert problem-solving strategies in many domains require the use of detailed mathematical techniques coupled with experiential knowledge about how and when to use the appropriate techniques. In many of these domains, such techniques are made available to experts in large software packages. In attempting to build expert systems for these domains, we wish to make use of these packages, and are therefore faced with an important problem: how to integrate the existing software, and knowledge about its use, into a practical expert system. The expert knowledge is used, in dynamic selection and interpretation of appropriate programs and parameters, to reach a successful goal in the problem solving. We describe the framework of a hybrid expert system for representing problem-solving knowledge in these domains. This hybrid system may be characterized as consisting of a production system and mathematical methods. The software package is reorganized as necessary to map it into the mathematical-method representation of a hybrid system. This approach has evolved out of an effort to build an expert system for performing well-log analysis, ELAS (expert log analysis system).     

A practical approach to software metrics

Metrics programs that create meaningful change in software practice must start with business goals in mind. Software metrics are quantitative standards of measurement for various aspects of software projects. A well-designed metrics program will support decision making by management and enhance return on the IT investment. There are many aspects of software projects that can be measured, but not all aspects are worth measuring. Starting a new metrics program or improving a current program consists of five steps: identify business goals; select metrics; gather historical data; automate measurement procedures; and use metrics in decision making     

A case-based approach to software reuse

This software reuse system helps a user build programs by reusing modules stored in an existing library. The system, dubbed caesar (Case-basEd SoftwAre Reuse), is conceived in the case-based reasoning framework, where cases consist of program specifications and the corresponding C language code. The case base is initially seeded by decomposing relevant programs into functional slices using algorithms from dataflow analysis. caesar retrieves stored specifications from this base and specializes and/or generalizes them to match the user specification. Testing techniques are applied to the construct assembled by caesar through sequential composition to generate test data which exhibits the behavior of the code. For efficiency, inductive logic programming techniques are used to capture combinations of functions that frequently occur together in specifications. Such combinations may be stored as new functional slices.     

A component-based approach to telecommunication software

This article discusses a domain-specific component-based architecture called distributed feature composition. Based on the well-known pipe-and-filter architecture, DFC has been refined for use in the telecommunication domain. The authors also point to ways this approach might work in other domains, including data networks     

A real-time software platform for the Cell processor

Scalability, efficiency, and programmability are essential for using the cell processor in consumer electronics. A real-time resource scheduler virtualizes the processor cores and ensures the application of real-time constraints at the system level. These features let the platform control resource usage and help exploit the power management features implemented in the cell processor.     

Manufacturing control systems: An approach to reducing software costs

Real-time control systems are expensive to develop and few of them operate properly when first delivered. Much of the development cost can be attributed to errors which are made in the early phases of the software development. These are often the hardest to detect and the most expensive to correct. The use of explicit models to test the consequences of design alternatives holds promise for reducing this problem. Simulation of both the physical and control systems provides the explicit models necessary not only to detect logical errors but also to examine the complex, dynamic relationships of control design decisions. Simulation with the “Activity Cycle” approach uses directed graphs to depict system logic for ease of comprehension and provides a one-to-one correspondence between the simulation and the desired manufacturing control system software. The use of Activity Cycle based design and simulation methods has the potential to reduce substantially the risks and costs involved in the construction of manufacturing control system software.     

Cacheminer: A runtime approach to exploit cache locality on SMP

Exploiting cache locality of parallel programs at runtime is a complementary approach to a compiler optimization. This is particularly important for those applications with dynamic memory access patterns. We propose a memory-layout oriented technique to exploit cache locality of parallel loops at runtime on Symmetric Multiprocessor (SMP) systems. Guided by application-dependent and targeted architecture-dependent hints, our system, called Cacheminer, reorganizes and partitions a parallel loop using the memory-access space of its execution. Through effective runtime transformations, our system maximizes the data reuse in each partitioned data region assigned in a cache, and minimizes the data sharing among the partitioned data regions assigned to all caches. The executions of tasks in the partitions are scheduled in an adaptive and locality-presented way to minimize the execution time of programs by trading off load balance and locality. We have implemented the Cacheminer runtime library on two commercial SMP servers and an SimCS simulated SMP. Our simulation and measurement results show that our runtime approach can achieve comparable performance with the compiler optimizations for programs with regular computation and memory-access patterns, whose load balance and cache locality can be well optimized by the tiling and other program transformations. However, our experimental results show that our approach is able to significantly improve the memory performance for the applications with irregular computation and dynamic memory access patterns. These types of programs are usually hard to optimize by static compiler optimizations     

A comprehensive approach to optimal software rejuvenation

Software aging is caused by resource exhaustion and can lead to progressive performance degradation or result in a crash. We develop experiments that simulate an on-line bookstore application, using the standard configuration of TPC-W benchmark. We study application failures due to memory leaks, using the accelerated life testing (ALT). ALT significantly reduces the time needed to estimate the time to failure at normal level. We then select the Weibull time to failure distribution at normal level, to be used in a semi-Markov model so as to optimize the software rejuvenation trigger interval. Then we derive the optimal rejuvenation schedule interval by fixed point iteration and by an alternative non-parametric estimation algorithm. Finally, we develop a simulation model using importance sampling (IS) to cross validate the ALT experimental results and the semi-Markov model, and also we apply the non-parametric method to cross validate the optimized trigger intervals by comparing the availabilities obtained from the semi-Markov model and those from IS simulation using the non-parametric method.     

A Model-Based Approach to Object-Oriented Software Metrics

The need to improve software productivity and software quality has put forward the research on software metrics technology and the development of software metrics tool to support related activities.To support object-oriented software metrics practice efectively,a model-absed approach to object-oriented software metrics is proposed in this paper.This approach guides the metrics users to adopt the quality metrics model to measure the object-oriented software products .The development of the model can be achieved by using a top-down approach.This approach explicitly proposes the conception of absolute normalization computation and relative normalization computation for a metrics model.Moreover,a generic software metrics tool-Jade Bird Object-Oriented Metrics Tool(JBOOMT)is designed to implement this approach.The parser-based approach adopted by the tool makes the information of the source program accurate and complete for measurement.It supports various customizable hierarchical metrics models and provides a flexible user interface for users to manipulate the models.It also supports absolute and relative normalization mechanisms in different situations.     

A new graph approach to minimizing processor fragmentation inhypercube multiprocessors

The authors propose a new approach for subcube and noncubic processor allocations for hypercube multiprocessors. The main idea is to represent available processors in the system by means of a prime cube graph (PC-graph). The PC-graph maintains the inter-relationships between free subcubes and hence reduces both internal and external processor fragmentations. Their simulation results show that the PC-graph approach outperforms the existing allocation strategies by 25% to 50% under certain load conditions