Agent trade servers in financial exchange systems

While typical solutions focus on fault tolerance (and specifically, exception handling) during the design and implementation phases of the software life-cycle (e.g., Java and Windows NT exception handling), more recently the need for explicit exception handling solutions during the entire life cycle has been advocated by some researchers. Several solutions have been proposed for fault tolerance via exception handling at the software architecture and component levels. This paper describes how the two concepts of fault tolerance and software architectures have been integrated so far. It is structured in two parts (overview on fault tolerance and exception handling, and integrating fault tolerance into software architecture) and is based on a survey study on architecting fault tolerant systems where more than fifteen approaches have been analyzed and classified. This paper concludes by identifying those issues that remain still open and require deeper investigation.

A comparative study of exception handling mechanisms for building dependable object-oriented software

Enterprise network architecture and management have followed the Internet's design principles despite different requirements and characteristics: enterprise hosts are administered by a single authority, which intrinsically assigns different values to traffic from different business applications.We advocate a new approach where hosts are no longer relegated to the network's periphery, but actively participate in network-related decisions. To enable host participation, network information, such as dynamic network topology and per-link characteristics and costs, is exposed to the hosts, and network administrators specify conditions on the propagated network information that trigger actions to be performed while a condition holds. The combination of a condition and its actions embodies the concept of the network exception handler, defined analogous to a program exception handler. Conceptually, network exception handlers execute on hosts with actions parameterized by network and host state.Network exception handlers allow hosts to participate in network management, traffic engineering and other operational decisions by explicitly controlling host traffic under predefined conditions. This flexibility improves overall performance by allowing efficient use of network resources. We outline several sample network exception handlers, present an architecture to support them, and evaluate them using data collected from our own enterprise network.

This paper shows how modern structuring techniques can be employed in integrating complex web applications such as travel agency systems. The main challenges the developers of such systems face are dealing with legacy web services and incorporating means for tolerating errors. Because of the very nature of such systems, exception handling is the main recovery technique to be applied in their development. We employ coordinated atomic actions to allow disciplined handling of such abnormal situations by recursively structuring the integrated system and by associating handlers with such actions. We use protective wrappers in such a way that each operation on legacy components is transformed into an atomic action with a well-defined interface. To accommodate a combined use of several ready-made environments (such as communication packages, services and run-time supports), we employ a multilevel exception handling. We believe that these techniques are generally applicable for both: structuring integrated web applications and providing their fault tolerance.

Component-based software systems built out of reusable software components are being used in a wide range of applications which have high dependability requirements. In order to accomplish the required levels of dependability, it is necessary to incorporate into these complex systems means for to cope with software faults. Exception handling is a well-known technique for adding forward error recovery to software systems supported by various mainstream programming languages. However, exception handling for component-based applications at the architectural level introduces new challenges which are not addressed by traditional exception handling systems, such as unavailability of source code, specially when off-the-shelf components are employed. In this paper, we present an exception handling system which adds fault tolerance to component-based systems at the architectural level. Our solution considers issues which are specific to component-based applications, such as unavailability of source code. We also present a framework which implements the proposed exception handling system for applications built using the C2 architectural style.KeywordsService RequestException HandlingArchitectural LevelDependable SoftwareClient ComponentThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

On Architecting Software Fault Tolerance using Abstractions

This paper discusses some of the typical characteristics of modern Web applications and analyses some of the problems the developers of such systems have to face. One of such types of applications is integrated Web application, i.e. application that integrates several independent Web services. The paper focuses on providing software fault tolerance for such systems. The solution we put forward employs the concept of co-ordinated atomic (CA) actions for structuring such applications and for providing fault tolerance using exception handling. The paper discusses important design and implementation decisions we have made while developing a travel agency (TA) case study and attempts to generalize them to allow CA actions to be easily applied for building dependable Web applications.

Green supply chain practices in the plastics industry in Portugal. The moderating effects of traceability, ecocentricity, environmental culture, environmental uncertainty, competitive pressure, and social responsibility

With the decreasing Mean Time Between Failures (MTBF) of high performance computing systems, process failure has become a normal phenomenon rather than an exception. The failures in high frequency lead to fault tolerance, a key feature of high performance applications. To provide fault tolerance interfaces for active message programs, this paper proposes a novel model called event-driven fault tolerance. The model converts each detected process failure into an event containing detailed failure information of the execution context, and then schedules the event up to application layer by executing user-directed event handlers to drive the program to recover from faults. Based on events, the model can provide applications with dynamic process groups and fault tolerant communication interfaces. We present an implementation of the model called EDFT (Event Driven Fault Tolerance) and describe its architecture, principle, components and application programming interfaces (API). To evaluate this model, we incorporate EDFT into a scientific application, PreStack Depth Migration (PSDM). Experiments are conducted by injecting various kinds of faults into PSDM when it is running. Experimental results show that for active message programs that demand high performance, event-driven fault tolerance model promises strong robustness, low overhead and high scalability.

Cloud data centers, realizing that the amount of unused resources is significant, have started offering them as transient resources with unpredictable, irreversible revocation. The use of transient resources indicates many relevant issues still pose critical challenges, including security, strong and reliable connectivity and fault-tolerance approaches. To effectively use transient cloud servers to fulfill user requests, it is necessary to define an appropriate fault-tolerant mechanism and its respective parameters to avoid data loss if an unexpected failure occurs. We present an agent-based framework, namely BRA2Cloud, for integrating bag-of-tasks enabled systems using unreliable transient resources. To guarantee application execution and better use of idle resources, it is necessary to create an execution plan through fault tolerance definitions to increase reliability. To do this, BRA2Cloud agents combine features to predict failures in a multi-agent architecture that dynamically creates fault-tolerant multi-strategies, considering the current availability scenario and providing a resilient environment according to users’ application needs. Our approach was validated using real data retrieved between 2017 and 2019 from Amazon Spot Instances. Exhaustive experiments achieved high accuracy levels, reaching a 91% survival prediction success rate, which indicates the model is effective under realistic working conditions. We consider the results promising, decreasing up to 74.48% in total execution time when compared to other approaches in the literature. As the main requirements of our proposal, we have defined a series of features that BRA2Cloud should have in order to address the impact of these definitions on resiliency provision, application execution time reduction, and monetary cost reduction.

The Internet of Things (IoT) demands real-time, low-latency processing of data generated by thousands of heterogeneous, resource-constrained devices. In such dynamic environments, ensuring fault tolerance becomes critical, especially for safety-sensitive applications like disaster management or patient monitoring. However, existing centralized fault tolerance solutions face serious scalability challenges across large, hierarchically connected IoT topologies. In this paper, we present Meerkat, a network-aware fault-tolerance protocol explicitly designed for IoT environments. Meerkat achieves zero-downtime recovery via redundant operator execution on disjoint paths and efficient duplicate detection. It also includes dynamic load balancing that adapts operator placement to device volatility, ensuring fair resource use. Compared to state-of-the-art techniques, Meerkat sustains up to 70× higher throughput with only 28% network overhead. These results highlight Meerkat's ability to deliver efficient fault tolerance with minimal overhead at IoT scale.

Mobile agent systems often require sophisticated cooperation and coordination during error detection and recovery. In this paper we propose novel fault tolerance mechanisms that support co-operative exception handling in such systems. The paper demonstrates how mechanisms like these can be formally developed and analysed. We start with identifying the typical modes of failures in agents and analysing possible failure and recovery scenarios in mobile systems. Stepwise refinement is used as our formal framework for top-down development and verification. Using the framework we formally verify the essential model properties, such as interoperability, local and global state consistency and termination of error recovery. Our approach provides developers with formal generic patterns for incorporating fault-tolerance mechanisms into mobile agent systems. We also demonstrate how the results of our formal development can be instantiated and reused in developing real-world agent software.

We describe a new public-domain open-source simulator of an electronic financial exchange, and of the traders that interact with the exchange, which is a truly distributed and cloud-native system that been designed to run on widely available commercial cloud-computing services, and in which various components can be placed in specified geographic regions around the world, thereby enabling the study of planetary-scale latencies in contemporary automated trading systems. Our simulator allows an exchange server to be launched in the cloud, specifying a particular geographic zone for the cloud hosting service; automated-trading clients which attach to the exchange can then also be launched in the cloud, in the same geographic zone and/or in different zones anywhere else on the planet, and those clients are then subject to the real-world latencies introduced by planetary-scale cloud communication interconnections. In this paper we describe the design and implementation of our simulator, called DBSE, which is based on a previous public-domain simulator, extended in ways that are partly inspired by the architecture of the real-world Jane Street Exchange. DBSE relies fundamentally on UDP and TCP network communications protocols and implements a subset of the FIX de facto standard protocol for financial information exchange. We show results from an example in which the exchange server is remotely launched on a cloud facility located in London (UK), with trader clients running in Ohio (USA) and Sydney (Australia). We close with discussion of how our simulator could be further used to study planetary-scale latency arbitrage in financial markets.

La introducción de pasturas es una alternativa de manejo válida para, entre otros beneficios, paliar el déficit forrajero del pastizal y aumentar los índices productivos de la majada en la región. Sin embargo, para el uso eficiente y sustentable de este recurso se requiere un conocimiento de los procesos involucrados. En este contexto, se desarrolló un estudio con el propósito de evaluar la dinámica de crecimiento de una pastura de Agropyron trichophorum y Agropyron intermedium en secano instalada en el Campo Experimental “Potrok Aike” en el Sur de Santa Cruz. En el trabajo se midieron variables morfo-genéticas y estructurales, como así también, los efectos climáticos y edáficos sobre las mismas.Los resultados obtenidos indican que, si bien la temperatura es un factor determinante en la dinámica de crecimiento de la vegetación, el contenido hídrico del suelo cumple un rol fundamental en el proceso descripto, limitando en muchos casos la elongación foliar de las plantas y la disponibilidad de los nutrientes.Por otra parte, se evidencio que las especies forrajeras introducidas en la pastura permiten hacer un uso eficiente de los recursos naturales disponibles, obteniendo más biomasa aérea en relación al pastizal natural y que su disponibilidad está fuertemente influenciada por las condiciones climáticas, que a su vez determinan el momento óptimo de cosecha.

To reduce the oversampling rate of baseband signals, decimation is widely used in digital communication systems. Polyphase filters (PPFs) can be used to efficiently implement decimators. SRAM-based FPGAs provide large amounts of resources combined with flexibility and are a popular option for the implementation of communication receivers. However, they are sensitive to soft errors, which limit their application in harsh environments, such as space. An initial reliability study on SRAM-based FPGA implemented decimation shows that the soft errors on around 5% of the critical bits in the configuration memory of the decimator would degrade the decimated signal dramatically. Based on this result, this paper proposes an efficient fault tolerance scheme, in which the high correlation between adjacent PPFs outputs is utilized to tolerate the fault of a single-phase filter, and a duplicate and comparison structure is used to protect the fault tolerance logic. Hardware implementation and fault injection experiments show that the proposed scheme can drastically reduce the number of critical bits that cause severe output degradation with 1.5x resource usage and 0.75x maximum frequency relative to the unprotected decimator. Therefore, the proposed scheme can be an alternative to Triple Modular Redundancy that more than triples the use of resources.