2367333
Building Accountability Middleware to Support Dependable SOA
The Intelligent Accountability Middleware Architecture (Llama) project supports dependable service-oriented architecture (SOA) monitoring, runtime diagnosis, and reconfiguration. At its core, Llama implements an accountability service bus that users can install on existing service-deployment infrastructures. It collects and monitors service execution data from a key subset of services; enables Llama users to incorporate others' advanced diagnosis models and algorithms into the framework; and provides enterprise service bus extensions for collecting service profiling data, thus making process problems transparent to diagnose. Finally, experimental results indicate that using Llama contributes a modest amount of system overhead.
11999738
The LLAMA Middleware Support for Accountable Service-Oriented Architecture
Enterprises are turning to SOA for the flexible deployment of business processes. While current monitoring tools can detect service execution problems in an enterprise's servers and report such problems to human decision makers, they may not closely monitor the external services they use, diagnose the root cause of process problems, and automatically reconfigure the process to replace faulty services. This paper presents the LLAMA middleware support for service process monitoring, run-time management, and configuration. Instances of accountability agents are deployed to selectively monitor some services' performance. These agents in turn allow LLAMA's Accountability Authority (AA) to diagnose process problems and apply any necessary reconfiguration. The project also builds tools to simplify the setup and deployment of LLAMA components. Our experimental results indicate that using LLAMA contributes only a modest amount of system overhead, and that the diagnosis process is swift and sufficiently accurate.
18478421
An Efficient Approach for Service Process Reconfiguration in SOA with End-to-End QoS Constraints
Using SOA, service processes can be composed statically or dynamically using services provided by different service providers. Some services may become faulty at runtime and cause the service process to violate the end-to-end quality of service (QoS) constraint. We propose an efficient approach for replacing faulty services to ensure that the reconfigured service process still meets the original end-to-end QoS constraint. We use an iterative algorithm to identify reconfiguration regions that have a small number of services, some faulty and some healthy, in order to have more service selection options. By reconfiguring services in these selected regions rather than the whole service process, the computational complexity is significantly reduced. Simulation study has shown that our approach is efficient as most service processes can be repaired by replacing only a small number of services.
32231750
A Hybrid Restoration Scheme Based on Threshold Reaction Time in Optical Burst-Switched Networks
Optical Burst-Switched (OBS) networks usually employ one-way reservation by sending a burst control packet (BCP) with a specific offset time, before transmitting each data burst frame (BDF). Therefore, a fiber link failure may lead to loss of several BDFs as the ingress nodes sending these BDFs remain unaware of the failed link till they receive the failure indication signal (FIS). In this paper, we propose a hybrid restoration scheme, wherein we employ a novel combination of sub-path as well as path restoration schemes. In particular, the upstream node preceding the failed link employs sub-path restoration as soon as it detects the failure. Thereafter, when the source ingress node receives the FIS message, it (source ingress node) takes over the responsibility and employs path restoration. However, sub-path restoration is exercised by the upstream node only if the remaining time intervals left for the yet-to-arrive BDFs (for which BCPs have already left the upstream node) are less than a minimum time interval (called as threshold reaction time). Performance of the proposed scheme is evaluated through extensive computer simulation using OPNET. Our results indicate that the proposed restoration scheme significantly reduces burst losses due to link failure and, thus, outperforms the existing restoration schemes.
18359963
Backup reprovisioning to remedy the effect of multiple link failures in WDM mesh networks
As networks grow in size and complexity, both the probability and the impact of failures increase. The pre-allocated backup bandwidth, which has been widely investigated in the literature, may not be able to provide full protection guarantee when multiple failures occur in a network. In this study, we consider multiple concurrent failures where concurrent means that a new failure occurs before a previous failure is repaired. To combat the effect of multiple concurrent failures, new backups can be reprovisioned after one failure such that the next potential failure can be handled effectively and efficiently. We consider dynamic traffic where a pair of link-disjoint primary and backup paths is provisioned when a new connection request arrives. After a failure occurs, the affected connections switch traffic from their primary paths to backup paths. To protect against next potential failure, we reprovision new backups for connections that become unprotected or vulnerable because of losing their primary or their backup due to the previous failure or due to backup resource sharing. This approach is called Minimal Backup Reprovisioning (MBR). An alternative approach is to globally rearrange backups for all connections after one failure occurs, which is called Global Backup Reprovisioning (GBR). Backup reprovisioning can be performed whenever the network's state changes, e.g., (1) when a new request arrives, (2) when an existing connection terminates, (3) when a network failure occurs, (4) when a failed link/node is repaired, etc., to utilize the available resources more efficiently or to recover quickly from the next failure. In this study, we perform MBR or GBR after one network failure occurs to protect against the next potential failure in a wavelength-convertible WDM mesh network. The link-vector network model which can maximally explore the backup-sharing potential is assumed in this study. We then analyze the complexity of MBR and GBR under such a network model. A reprovisioning algorithm is proposed for MBR which can significantly reduce the connection vulnerability without the knowledge of the location of the next failure. In GBR, both integer linear program (ILP) and heuristic-based approaches are proposed. We compare capacity requirement and computational complexity of MBR to that of GBR through numerical examples. MBR demonstrates a good tradeoff between complexity and capacity efficiency to handle multiple concurrent failures
31253731
Explicit Routing for Traffic Engineering in Labeled Optical Burst-Switched WDM Networks
Optical burst switching (OBS) is a promising technique for supporting high-capacity bursty data traffic over optical wavelength-division-multiplexed (WDM) networks. A label-switched path can be established to forward a burst control packet (BCP) if each OBS node is augmented with an IP/MPLS controller. Such a network is called a labeled OBS (LOBS) network, and it can exploit the explicit routing and constraint-based routing properties supported in the MPLS framework to perform traffic and resource engineering. In this paper, we consider the traffic-engineering problem in a LOBS network, using explicit routing to balance network load and to reduce the burst-loss probability. We model the traffic-engineering problem in a LOBS network as an optimization problem and propose two new objective functions to minimize network congestion. Our illustrative numerical examples show that the burst-loss probability can be significantly reduced using optimization technique, when compared with shortest-path routing.
606471
A dynamic scalable service model for SIP-based video conference
As an extensible signaling protocol, SIP (session initiation protocol) can be applied in developing video conference system. Traditionally, for SIP-based centralized video conference system, conferencing scale is limited by both the capability of conference server and the availability of bandwidth. The paper focuses on how to keep conferencing when the number of conference users increases. Based on the study of the SIP protocol, we analyze the drawback of the existing video conference model, and propose a dynamic scalable service model for SIP-based video conference. By this model, the extra service requests can be transferred and served in the cooperated conference servers. The paper presents the conferencing control policy of the model in detail. We developed a prototype of video conference system based on the above model. Experimental results show this service model works well.
1034257
A Web Service Adapter with Contract-Oriented Methodology
Loose coupling is a cornerstone for Service-Oriented Architecture (SOA). Service contracts enable loose coupling, because they conceal internal details of services from the outside world behind the facade. However, current works on service oriented analysis and design (SOAD) largely focus on defining processes for developing business processes and services without considering variability in details. In this paper, a Web Service adapter of service-contract oriented is presented in order to enhance the applicability and reusability of such services. We also introduce some critical issues about service contract analysis engine, skeleton code generate engine and web-based WSDL editor in the Web Service adapter. Additionally, the Web Service adapter designed in this paper is compared with related tools, and the results indicate that our methods demonstrate a more desirable interactivity and stability.
14662457
Framework for Performance Evaluation of Face, Text, and Vehicle Detection and Tracking in Video: Data, Metrics, and Protocol
Common benchmark data sets, standardized performance metrics, and baseline algorithms have demonstrated considerable impact on research and development in a variety of application domains. These resources provide both consumers and developers of technology with a common framework to objectively compare the performance of different algorithms and algorithmic improvements. In this paper, we present such a framework for evaluating object detection and tracking in video: specifically for face, text, and vehicle objects. This framework includes the source video data, ground-truth annotations (along with guidelines for annotation), performance metrics, evaluation protocols, and tools including scoring software and baseline algorithms. For each detection and tracking task and supported domain, we developed a 50-clip training set and a 50-clip test set. Each data clip is approximately 2.5 minutes long and has been completely spatially/temporally annotated at the I-frame level. Each task/domain, therefore, has an associated annotated corpus of approximately 450,000 frames. The scope of such annotation is unprecedented and was designed to begin to support the necessary quantities of data for robust machine learning approaches, as well as a statistically significant comparison of the performance of algorithms. The goal of this work was to systematically address the challenges of object detection and tracking through a common evaluation framework that permits a meaningful objective comparison of techniques, provides the research community with sufficient data for the exploration of automatic modeling techniques, encourages the incorporation of objective evaluation into the development process, and contributes useful lasting resources of a scale and magnitude that will prove to be extremely useful to the computer vision research community for years to come.
1234512
HOS-Miner: A System for Detecting Outlying Subspaces of High-dimensional Data
We identify a new and interesting high-dimensional outlier detection problem in this paper, that is, detecting the subspaces in which given data points are outliers. We call the subspaces in which a data point is an outlier as its Outlying Subspaces. In this paper, we will propose the prototype of a dynamic subspace search system, called HOS-Miner (HOS stands for High-dimensional Outlying Subspaces), that utilizes a sample-based learning process to effectively identify the outlying subspaces of a given point.
31337744
Information Strategies to Support Full Information Product Pricing: the Role of Trust
In this paper, we report the importance of trust in the development and operation of distribution networks that attach non-price information to products to mitigate market dynamics introduced by information asymmetries. Often this non-price information is transmitted from producers to consumers through trusting networks or under certifiable labels such as Organic or Fair Trade. We are calling such networks Full Information Product Pricing (FIPP) Networks. This study is part of a larger project aimed at understanding the characteristics of FIPP networks. This initial exploration on four cases in Canada and Latin America indicated that trust, in the forms of institutional trust, calculative trust, and relational trust, plays key roles in FIPP operations and expansion. It is critical for building collaboration, coordinating network activities, and mitigating the risks associated with information asymmetry.