A security framework for reflective Java applications

The advent of component‐based reflective applications raises the issue of protecting baselevel components from the actions performed by metalevel components. However, by their very nature, reflective applications are far more difficult to secure than non‐reflective applications, which certainly explains why the problem has received very little attention so far. In this paper we present a security framework for enforcing access control between metalevel components and the baselevel components they reflect on. Rather than designing a new security architecture from scratch, we extend the standard security architecture of Java to provide security for a fully‐functional proxy‐based MOP for Java. We implement a number of well‐known meta‐level behaviors and study their security requirements, the results of which support our design choices. Copyright © 2003 John Wiley & Sons, Ltd.     

Merging C and assembly language in microcontroller applications

A number of microcomputer and microcontroller applications have small production runs or require quick prototyping to allow for concurrent development of other parts of the system which depend on functional, if not final, code. In these cases, the ease, speed, and reduced errors associated with coding the operating program in a high-level language justify its usage. The reduction in non-recurring engineering costs more than compensates for the increased recurring product costs and therefore makes sense from a total cost perspective. A model of the software design cycle is introduced here which considers software development as starting at the highest language level possible and only those sections of code which require streamlining for reasons of increased execution speed or reduced program storage being re-coded into assembly language. Examples are given of how to use the C language to directly address hardware components and memory and how to effectively link assembly language and C into a single functional program.     

Making RAD work for your project

For several good business reasons, rapid application development has become increasingly popular. In general, RAD gives you earlier product payback and more payback time before the pace of technology makes your product obsolete. For software product sales, RAD also helps you debut a product earlier in a market window, which lets the product capture more market share, revenues, and profits. To gain maximum benefit from RAD, however, you must choose the RAD form that best suits your project. The article presents the various forms of RAD available and give advice on which to choose     

A toolkit for efficient numerical applications in Java

Java is widely recognized as a good object-oriented programming language. However, it is often considered as too slow for numerically intensive applications. This paper presents a software toolkit that brings the computational efficiency of numerical Fortran libraries to Java. The toolkit is organized in two layers. In the first layer, Java wrappers provide access to numerical libraries like BLAS, LAPACK or NAG. The second layer comprises vector and matrix classes as well as classes for common linear algebra tasks. Numerical experiments show that this strategy can substantially improve the performance of Java-based numerical applications.     

Making CM work for software development

Configuration management (CM) is an old engineering concept that developers are adapting for software development. Given software's increasing complexity, the need for a transition from the mechanical world to digital products is clear: CM helps manage and smoothly integrate change into a complex system. Managing all change is an extremely broad umbrella and needs a clear delineation     

Making infrastructure visible for nomadic work

In this study we revisit Weiser’s (1991) [5] vision of seamlessly integrated computing. We focus on nomadic workers who rely extensively on mobile technologies to conduct work. Using Star and Ruhleder’s (1996) [10] properties of infrastructure, we discuss how nonroutine users of infrastructure face particular challenges. We conducted an ethnographic investigation of nomadic workers in a large distributed organization. We examined strategies that they use to assemble their mobile office, to seek resources, and to synchronize with others across time zones. We discuss how their strategies are challenged by their lack of local knowledge of infrastructure. Our results suggest that until the field of pervasive computing can attain Weiser’s vision, the very users of ubiquitous computing need infrastructure to be visible. We discuss the implications for a design to support nomadic work.     

Making telecommuting work

Addresses how to make telecommuting work for software managers. It is possible to create a telecommuting culture-an environment in which people can successfully work from wherever they happen to be physically. The critical component of that culture is building and maintaining an open and trustful communication between the manager and the employee and between the employee and the rest of the team. One way to build that three-way communication is to create a track record of successful deliverables by clarifying the work required, facilitating interaction rules, clarifying how people work with each other one-on-one, and specifying how the telecommuter participates with the team     

Refactoring techniques for aggressive object inlining in Java applications

Object Inlining (OI) is a known optimization in object oriented programming in which referenced objects of class B are inlined into their referencing objects of class A by making all fields and methods of class B part of class A. The optimization saves all the new operations of B type objects from class A and at the same time replaces all indirect accesses, from A to fields of B, by direct accesses. To the best of our knowledge, in-spite of the significant performance potential of the OI optimization, reported performance measurements were relatively moderate. This is because an aggressive OI optimization requires complex analysis and code transformations to overcome problems like multiple references to the inlinable object, object references that escape their object scope, etc.     

Sync: a Java framework for mobile collaborative applications

Introducing the factors of wireless mobile systems into the development of collaborative applications complicates developers' lives significantly. Application frameworks targeted for coordinating wireless mobile applications simplify development. The authors describe Sync, a development framework that provides high-level primitives that enable programmers to create arbitrarily complex, synchronized, replicated data objects. Designed for wireless networks, Sync enables applications to share changes at a granularity as small as updates to basic types and so enables better performance on low-bandwidth connections     

Robustness testing of Java server applications

This paper presents a new compile-time analysis that enables a testing methodology for white-box coverage testing of error recovery code (i.e., exception handlers) of server applications written in Java, using compiler-directed fault injection. The analysis allows compiler-generated instrumentation to guide the fault injection and to record the recovery code exercised. (An injected fault is experienced as a Java exception.) The analysis 1) identifies the exception-flow "def-uses" to be tested in this manner, 2) determines the kind of fault to be requested at a program point, and 3) finds appropriate locations for code instrumentation. The analysis incorporates refinements that establish sufficient context sensitivity to ensure relatively precise def-use links and to eliminate some spurious def-uses due to demonstrably infeasible control flow. A runtime test harness calculates test coverage of these links using an exception def-catch metric. Experiments with the methodology demonstrate the utility of the increased precision in obtaining good test coverage on a set of moderately sized server benchmarks.     

Making IT outsourcing work for smaller enterprises

Small and midsize enterprises - those with fewer than 100 employees - make up 95 percent of all US companies, and they collectively employ more than a third of the country's workforce. For companies of this size - and for regional and branch offices of large companies - deciding whether to outsource IT services can be a daunting task. Does IT outsourcing make sense for smaller firms? Done wisely, it can lower costs, focus in-house staff and eliminate wasted capacity.     

Klava: a Java package for distributed and mobile applications

Highly distributed networks have now become a common infrastructure for wide‐area distributed applications whose key design principle is network awareness, namely the ability to deal with dynamic changes of the network environment. Network‐aware computing has called for new programming languages that exploit the mobility paradigm as a basic interaction mechanism. In this paper we present the architecture of KLAVA , an experimental Java package for distributed applications and code mobility. We describe how KLAVA permits code mobility by relying on Java and present a few distributed applications that exploit mobile code programmed in KLAVA . Copyright © 2002 John Wiley & Sons, Ltd.     

Mechanisms for object caching in distributed applications using Java RMI

Remote Method Invocation (RMI), a mechanism to access remote objects in Java‐based distributed applications, uses network communication for each method invocation. Consequently, using RMI in a wide‐area environment can cause poor application performance. One solution to improve performance is to cache the objects such that network communication is not necessary for each method invocation. In this paper, we present mechanisms to transparently add object caching to RMI. These mechanisms are compatible with existing RMI applications and use an event‐based model to support different consistency policies. The mechanisms also include the ability to adaptively select the consistency policy for an object based on its usage pattern. A novel feature of our mechanisms is the use of a ‘reduced object’, which is a partial representation of the RMI object. We experimentally evaluate and demonstrate the benefits of our mechanisms. Copyright © 2006 John Wiley & Sons, Ltd.     

Dynamic load‐balancing mechanism for distributed Java applications

Program environments or operating systems generally leave the decision on the allocation of program entities to the developer, offering either placement directives, or tools available through the manipulation of a graphical interface. These approaches cannot always take into account the dynamic behavior of applications, dynamicity in the execution environment or the heterogeneity of the execution platform. Transparent deployment algorithms are necessary for automizing and optimizing application distribution. The Adaptive Distributed Applications in Java (ADAJ) project deals with placement and migration of Java objects. It automatically deploys parallel Java applications on a cluster of workstations using monitoring information about the application behavior. The transparency obtained through the integration of these tools in the middleware makes such an environment easy to use and improves efficiency. Copyright © 2005 John Wiley & Sons, Ltd.     

Towards module-based automatic partitioning of Java applications

When reengineering a monolithic application to be a distributed one, programmers always have to decide how many distributed parts the application should be partitioned, and write many codes related to where a partwill be placed on network nodes and how these parts communicate with each other through the network. These codes usually have nothing to do with the business functions of the application, and they are laborious to write. In addition, as the distribution architecture of the application is finalized beforehand, it may not adapt well to the ever-changing execution environment. In this paper, we propose DPartner, an automatic partitioning system, to help programmers create a distributed Java application without explicitly writing the distribution-related codes. Unlike the other partitioning systems, DPartner does not partition an application directly into the coarse-grained client and server. Instead, it first partitions the application into several modules where each module performs a relatively independent business function of the application. Then it makes these modules be distributable through automatic bytecode rewriting. These modules can distribute in different nodes and cooperate to work just as the original monolithic application. Such a module-based partitioning approach enables a relatively easy reshaping of the distribution architecture of an application, which facilitates the application adapt to the environmental changes without manual recoding or repartitioning with regard to distribution. This paper gives the detailed design of DPartner, and evaluates it using real-world applications. The evaluation results demonstrate the effectiveness and efficiency of DPartner.     

Mobile digital datalink for field work applications

A data communications system has been designed to link mobile field instruments with digital I/O to a central computer or data logger. Commercially available VHF transceivers are used. The system is designed to be sufficiently flexible to provide for either parallel or serial devices and to allow the user to select whatever end-of-text characters (or number of characters of text) are demanded by the protocols of the field instrument and the computer.     

Making optical Fourier filtering work

During the work by many scientists over the last 50 years, we have solved many of the problems that seemed to be holding the field back: System layout, lenses specialized for this purpose, suitable detector arrays, SLMs for input and for filtering, designs for filters, online evolution of filters, and so forth. Yet it is hard to find this technology in use anywhere. Something is clearly wrong, and we know one major problem that has never been solved and, in fact, is seldom acknowledged in print: Only very simple problems are linearly discriminable, so they cannot be discriminated well by a linear discriminant. But, the wonderful property of correlating all parts of the input pattern in parallel is only possible by Fourier methods. We see no way whatever for overcoming the contradictory goals of space or time invariant operations and need of implementing the most powerful nonlinear discriminants (clearly this can only be done with nonlinear discriminants). Those two contradictory goals seem to condemn Fourier filtering (electronic or optical) to being interesting but not very helpful. As this is a paper on a new kind of pattern recognition and it is not limited to Fourier optics, it is important to provide some useful concepts in Pattern Recognition. Our discussion is simple and brief. It has no proofs but it does offer the reader some of the concepts that help in understanding the new aspects of the material presented here. This work will not propose or develop improvements on any of the configurations and components. This is a study of the way Fourier filtering can have it both ways. Prior analyses are still valid, but, at a higher level, we can have it both ways. This review is aimed at allowing both the space or time invariant filtering while implementing an extremely powerful linear discriminants. Aspects of this have been published but in a regrettably short form and with very little of the background on pattern recognition. Here, we begin with a brief introduction to pattern recognition as will be needed to make this review finite. After the way to achieve powerful target discrimination and target location is shown, I describe how to apply it to optical Fourier filtering for pattern recognition. Some situations seem more likely to use Optical Fourier pattern recognition than others. We explore some of those.