In the field of embedded systems there is a tendency towards distributed mobile environments relying on wireless networking. These inherently dynamic environments present new challenges for system reliability. One basic building block for reliability support at the software level is reliable group communication.However, traditional implementations of such a service are unsuitable for wireless and embedded environments, in which bandwidth and power consumption limitations exist. In this paper we present a group communication service optimized for mobile ad-hoc networks which provides reliable communication for a subset of stable nodes. These stable nodes can then use reliable communication to implement higher-level reliability services such as replication.

SUDA2 is a recursive search algorithm for minimal unique itemset detection. Such sets of items are formed via combinations of non-obvious attributes enabling individual record identification. The nature of SUDA2 allows work to be divided into non-overlapping tasks enabling parallel execution. Earlier work developed a parallel implementation for SUDA2 on an SMP cluster, and this was found to be several orders of magnitude faster than sequential SUDA2. However, if fixed-granularity parallel tasks are scheduled naively in the order of their generation, the system load tends to be imbalanced with little work at the beginning and end of the search. This paper investigates the effectiveness of variable-grained and dynamic work generation strategies for parallel SUDA2. These methods restrict the number of sub-tasks to be generated, based on the criterion of probable work size. The further we descend in the search recursion tree, the smaller the tasks become, thus we only select the largest tasks at each level of recursion as being suitable for scheduling. The revised algorithm runs approximately twice as fast as the existing parallel SUDA2 for finer levels of granularity when variable-grained work generation is applied. The dynamic method, performing level-wise task selection based on size, outperforms the other techniques investigated.

In this paper, we propose an enhanced version of the HB-MP authentication protocol, called the HB-MP+ protocol. The HB-MP protocol is a lightweight authentication protocol that is suitable for use in passive radio frequency identification (RFID) systems. The HB-MP+ protocol overcomes the man-in-the-middle attack to which the basic HB-MP protocol is vulnerable while maintaining its suitability to low-cost passive RFID systems. We show an effective man-in-the-middle attack against the HB-MP protocol where the attacker utilizes the predictable rotation of the secret key. We enhance the HB-MP protocol by randomizing the rotation of the secret key, which eliminates the vulnerability. We also propose the use of round keys that may be produced by rotation or, more generally, by a one-way function. We analyse the security and performance improvements of our HB-MP+ protocol and find it to be suitable for passive RFID systems.

Using RFID to verify the simultaneous presence of more than one tag has generated interest since the Yoking Proof mechanism was proposed by A. Juels (2004). Various protocols have been proposed ever since. However, all these protocols require that the tags are ordered in a certain way. This article proposes an order-independent protocol which improves the efficiency and reduced failure rates. Privacy is also protected by not sending the identity in plain text.

Sensor network operating systems have to operate with limited hardware resources. Constraints on power consumption greatly reduce the resources available to such an operating system. Therefore, current systems restrict application flexibility and tend to impose certain programming paradigms, such as event-driven programming. The Arena operating system is a special-purpose embedded operating system that has the potential to overcome these problems. The operating system is based on a strict separation of mechanism and policy. All operating system policies are placed in user-level libraries. These libraries can be loaded and replaced using a dynamic code loader, in order to configure the operating system dynamically. The dynamic code loader can also be used to load and replace arbitrary application components.

This position paper presents an overview of the Mobile Java Card Grid project that consists in setting up a grid like mobile infrastructure based on SIM cards. It combines the Java Card Grid infrastructure developed at the LaBRI, the SIM experience and tools of the Royal Holloway University of London, and some features of the MADNESS project developed at the XLIM.

Sensitive systems that are based on smart cards use protocols and algorithms that have usually been subjected to rigourous analysis by the cryptographic community. Attackers have therefore sought other means to circumvent the security of the protocols and algorithms used in smart card based systems. As smart cards are small, portable devices they can easily be put in a situation where their behaviour can be observed. The simplest form of analysis of this type is intercepting al the

In this paper, a practical electronic-payment (epayment) protocol is presented for use over the internet. The protocol applies the principle of true fair-exchange to the process of purchase and physical delivery via an ecommerce system without the involvement of third party, whilst maintaining customer and merchant anonymity.

Ten or more forward speeds and two or more reverse speed are achieved by a planetary gear train of an automatic transmission that includes three planetary gear sets mounted on an input shaft, an output shaft disposed in parallel with the input shaft and having an output gear. The transmission further includes six shafts respectively interconnecting corresponding elements among the input shaft and rotational elements of the three planetary gear sets, a first transfer gear selectively delivering torque between one of the six shafts and the output shaft; and a second transfer gear selectively delivering torque between the output shaft and one rotational element of the third planetary gear set.

In this paper, we present a user-centric m-payment solution over Internet. The main contribution of the proposed solution includes: 1: ensuring fair-exchange; 2: ensuring the user's anonymity and privacy protection; 3: implementing an embedded biometric authentication framework for high security requirement

The use of certificates for secure transactions in smart cards requires the existence of a secure and efficient revocation protocol. There are a number of existing protocols for online certificate revocation and validation, among which OCSP and SCVP are the most widely used. However there are not any real applications testing the efficiency of these protocols when run in a smart card, even though the advantages of such an implementation are promising. In this paper we examine the details of the implementation of these protocols, emphasising on the issues arisen from the limitations of the smart cards. We also discuss the performance results from the implementation of OCSP and SCVP in a multi-application smart card environment. Results from two different Java Card platforms are presented and analyzed.

The importance of being able to classify records according to disclosure risk is well understood; Skinner and Holmes (1998), Fienberg and Makov (1998). One concept for so classifying records is called special uniqueness; see Elliot (2000), Elliot et al (2002), Manning and Haglin (2005). This paper describes SUDA (Special Uniques Detection Algorithm) which is both a set of computer science algorithms and indeed a fully functioning software system for detecting and grading special uniques. Section 1 describes the basic design principles behind the sequential SUDA algorithm. Section 2 describes the software (now in use at the UK Office for National Statistics and Australian Bureau of Statistics). Section 3 describes recent advances (i) in parallelising SUDA and improving the algorithm so that cross-classifications of up to 60 variables can be comprehensively analysed (ii) in developing a version of SUDA for Grid computing.

Over the past decade a variety of process languages have been defined, used and evaluated. It is now possible to consider second generation languages based on this experience [1, 3, 4]. Rather than develop a second generation wish list this position paper explores two issues: instances and connectors. Instances relate to the relationship between a process model as a description and the, possibly multiple, enacting instances which are created from it. Connectors refers to the issue of concurrency control and achieving a higher level of abstraction in how parts of a model interact. We believe that these issues are key to developing systems which can effectively support business processes, and that they have not received sufficient attention within the process modelling community. Through exploring these issues we also illustrate our approach to designing a second generation process language.(1)

— Traditionally, configuration of operating systems is done statically at compile-or link-time, but recently dynamic run-time configuration has become possible. Embedded systems however have constraints, such as limited memory and real-time requirements, that prevent many dynamically configurable operating systems from being used in an embedded system. Dynamic configuration has associated limitations: either execution time overheads, due to complex code structures, or restricted flexibility. However, loading compiled code and linking it immediately at load-time avoids many of these overheads. This paper describes efficient dynamic loading and linking techniques employed as part of the Arena special-purpose operating system to allow embedded systems to be configured by replacing resource managers, such as the process manager. In Arena operating system managers reside in user-level libraries. A general-purpose loading-framework, designed specifically for embedded systems, is introduced and two case-studies are described to show the flexibility of the system. Performance measurements are presented to show that there is no measurable overhead introduced by the dynamic loading framework after the actual installation of a resource manager. This paper describes the results obtained by the work presented as “work in progress” at the 24th IEEE Real-Time Systems Symposium [1].

Traditionally, configuration of operating systems is done statically at compileor link-time, but recently dynamic runtime configuration has become possible. Embedded systems however have constraints, such as limited memory and real-time requirements, that prevent many dynamically configurable operating systems from being used in an embedded system. This paper describes efficient dynamic loading and linking techniques employed as part of the Arena special-purpose operating system to allow embedded systems to be configured by replacing resource managers, such as the process manager.

Network protocol stacks are traditionally encapsulated within system software, forcing the application programmer to use general-purpose communication end-point abstractions. The application programmer is denied the flexibility of implementing application-specific performance improvements. Application-level networking provides the application programmer with the ability to tailor the protocol stack to the needs of the application. This is particularly useful in special-purpose systems, such as embedded networked appliances. We describe the design of an application-compliant TCP/IP implementation for the Arena runtime library operating system, which aims at separating mechanism from policy. The role of policy and mechanism in network protocols and their effects on networked embedded systems is investigated. The resulting system is optimised for embedded systems based on a multithreaded single-application model. Experiments were carried out on an embedded system test platform and performance results are given.

Process systems aim to support many people involved in many processes over a long period of time. They provide facilities for storing and manipulating processes in both the representation and enactment domains. This paper argues that process systems should support ongoing transformations between these domains, at any level of granularity. The notion of creating an enactment model instance from a representation is merely one special case transformation. The case for thinking in terms of model instances is weak, especially when process evolution is considered. This argument is supported by our experience of the ProcessWeb process system facilities for developing and evolving process models. We introduce the idea of hyper-code, which supports very general transformations between representation and enactment domains, to offer the prospect of further improvements in this area.

Proceedings, International Workshop on Feedback and Evolution in Software and Business Processes (FEAST 2000), Imperial College, London. Supported by EPSRC