1701823
Dynamic checking of temporal constraints for concurrent workflows
At present, workflow management systems have not sufficiently dealt with the issues of time, involving time modelling at build-time and time management at run-time. They are lack of the ability to support the checking of temporal constraints at run-time. Although some approaches have been devised to tackle this problem, they are limited to a single workflow and use only static techniques to verify temporal constraints. In reality, there are multiple workflows executing concurrently in a workflow management system. There may well exist resource constraints between these concurrent workflows, which affect significantly the verification of temporal constraints at run-time. This paper proposes a novel approach for dynamic verification of temporal constraints for concurrent workflows. We first investigate resource constraints in workflow management systems, and then define concurrent workflow executions. Based on these definitions, we propose a verification method by analysing the temporal relationship and resource constraints between activities among concurrent workflows.
2679071
A generic operation transformation scheme for consistency maintenance in real-time cooperative editing systems
In real-time cooperative editing systems, independent operations on any part of the shared document may be generatedfrom multiple cooperatingsites. It is very important and technically challenging to ensure that the effect of executing an operation at remote sites, in the presence of concurrent execution of independent operations, achieves the same effect aa executing this operation at the local site at the time -of ita generation, thuspreaeruing its intention and maintainingsystern consistency. In this paper, we investigate the technical issues involved in preserving intentions of concurrent operuCons, explain the reaaons why traditional serialization-based concurrency control strategies and existing operational transformation strategies failed to solve these problems, and propose a generic operation transformation scheme for intention preservation and consistency maintenance in real-time cooperative editing systems. The proposed scheme has been implemented in an Internet-based prototype REDUCE (REaLtime Distributed Unconstrained Cooperative Editing) system. is quick (idealy as quick as a single-user editor) and the latency for remote user actions is low (determined by external commkkation latency only). (2) Distributed environments cooperating users may reside on different machines connected by different communication networks. (3) Unconstrained collaboration mdtiple users may concurrently and freely edit, any part of the document at any time, as advocated in [2, 8, 91.
43250103
An Agent-Based Ontological Approach for Information Reorganisation
This paper presents a novel approach for information reorganisation which is particularly suitable for distributed computing, such as Web services. An agent-based architecture is developed to cope with service agents' on and off and provide semantic support for implementation of complex e-business applications that may span diverse enterprises. A frame-based ontology representation is discussed. The representation is well suited for representing complex relationships that are unavailable in current ontology related work. Our approach aims to support dynamic information reorganisation in the Internet based e-business applications. The obtained information can serve for the knowledge acquisition purpose.
2707132
Resource constraints analysis of workflow specifications
A workflow specification is a formal description of business processes in the real world. Its correctness is critical to the workflow execution and hence the realisation of business objectives. In addition to structural and temporal constraints, resource constraints are also implied in workflow specifications. Therefore, they should be analysed to ensure that the workflow specification is resource consistent at build-time. In this paper, we first identify the problem of resource constraints in a workflow specification. Then we propose an innovative approach with corresponding algorithms to the checking of resource consistency for a workflow specification. Furthermore, we extend our analysis work to timed workflow specifications, where time information is taken into consideration for the checking of the resource consistency of a workflow specification. The work reported in this paper provides a theoretical foundation for workflow modeling and analysis in workflow management.
14000419
Using an experimental study to develop group awareness support for real-time distributed collaborative writing
Supporting group awareness is vital for the success of real-time, distributed, collaborative writing systems. Many awareness mechanisms have been introduced, but highly effective solutions are few. The research presented in this paper focuses on the development of awareness mechanisms using an experimental study of synchronous distributed collaborative writing. Our study has made two major contributions to research on group awareness. First, the study compares the importance of different awareness elements in supporting group awareness for collaborative writing. The results of our Wilcoxon test on awareness elements identify the five most important elements, including ‘‘Being able to comment on what other users have done,’’ ‘‘Knowing what actions other users are currently taking,’’ ‘‘Providing a communication tool when audio is not available,’’ ‘‘Knowing other user’s working areas in the document,’’ and ‘‘Knowing other user’s tasks.’’ Second, the research proposes mechanisms corresponding to the above-mentioned five awareness elements. The mechanisms include Dynamic Task List (DTL), Modification Director (MD), Advanced Chat (AC) and Split Window View (SWV). These mechanisms provide support for various aspects of group awareness, and add many enhanced features to existing awareness mechanisms. For example, DTL presents high-level information about authors’ responsibilities and the correlation between their work allocations. MD notifies users instantaneously whenever their work is modified by other authors. AC enhances communication between users by allowing them to attach document objects such as text and diagrams to a conversation message. And, SWV provides the views of other authors’ working areas and viewing areas simultaneously. � 2005 Elsevier B.V. All rights reserved.
4917474
Effective Visualisation of Workflow Enactment
Although most existing teamwork management systems support user-friendly interface to some extent, few of them have take into consideration of the special requirements of workflow visualisation. This paper realises the unique features of visualisation for run-time workflow, i.e., workflow enactment and execution. We present a detailed discussion of the emerging problems against the general aesthetic criteria for drawing the workflow layout. In order to support most essential workflow enactment facilities, the following three mechanisms are provided. Firstly, Sugiyama algorithm has been systematically incorporated into our prototype to create well structured workflow layout initially. Secondly, when the workflow process dynamically changes, we can adjust workflow layout by our force-scan algorithm to retain the mental maps created earlier among team members. Thirdly, we have also applied the technique of the fisheye view to offer a context focus mechanism for workflow users and to utilise the screen size more effectively. With these visualisation techniques, a better atmosphere may be facilitated for teamwork.
306973
A Loss Function Analysis for Classification Methods in Text Categorization
This paper presents a formal analysis of popular text classification methods, focusing on their loss functions whose minimization is essential to the optimization of those methods, and whose decomposition into the training-set loss and the model complexity enables cross-method comparisons on a common basis from an optimization point of view. Those methods include Support Vector Machines, Linear Regression, Logistic Regression, Neural Network, Naive Bayes, K-Nearest Neighbor, Rocchio-style and Multi-class Prototype classifiers. Theoretical analysis (including our new derivations) is provided for each method, along with evaluation results for all the methods on the Reuters-21578 benchmark corpus. Using linear regression, neural networks and logistic regression methods as examples, we show that properly tuning the balance between the training-set loss and the complexity penalty would have a significant impact to the performance of a classifier. In linear regression, in particular, the tuning of the complexity penalty yielded a result (measured using macro-averaged F1) that outperformed all text categorization methods ever evaluated on that benchmark corpus, including Support Vector Machines.
14988023
Modeling the Effect of Transmit Power and Physical Carrier Sense in Multi-Hop Wireless Networks
In this paper, we extend both Bianchi's and Kumar's models and characterize the channel activities governed by IEEE 802.11 DCF in multi-hop wireless networks from the perspective of an individual sender. In particular, we incorporate the effect of PHY/MAC attributes (such as transmit power and physical carrier sense) that need not be considered in WLANs but become extraordinarily important in multi-hop wireless networks, and derive the throughput attained by each sender. With the use of the analytical model derived, we investigate the impact of transmit power and carrier sense threshold on network capacity, and identify a simple operating condition under which the network may attain throughput that is close to its optimal value.
891317
Translingual Information Retrieval: A Comparative Evaluation
Translingual information retrieval TIR con sists of providing a query in one language and searching document collections in one or more di erent languages This paper introduces new TIR methods and reports on comparative TIR experiments with these new methods and with previously reported ones in a realistic setting Methods fall into two categories query trans lation based and statistical IR approaches es tablishing translingual associations The re sults show that using bilingual corpora for au tomated extraction of term equivalences in con text outperforms other methods Translin gual versions of the Generalized Vector Space Model GVSM and Latent Semantic Indexing LSI perform relatively well as does translin gual pseudo relevance feedback PRF All showed relatively small performance loss be tween monolingual and translingual versions Query translation based on a general machine readable bilingual dictionary heretofore the most popular method did not match the per formance of other more sophisticated methods Also the previous very high LSI results in the literature were discon rmed by more realistic relevance based evaluations
7974265
A Probabilistic Model for Online Document Clustering with Application to Novelty Detection
In this paper we propose a probabilistic model for online document clustering. We use non-parametric Dirichlet process prior to model the growing number of clusters, and use a prior of general English language model as the base distribution to handle the generation of novel clusters. Furthermore, cluster uncertainty is modeled with a Bayesian Dirichlet-multinomial distribution. We use empirical Bayes method to estimate hyperparameters based on a historical dataset. Our probabilistic model is applied to the novelty detection task in Topic Detection and Tracking (TDT) and compared with existing approaches in the literature.
17079123
Applying CLIR Techniques to Event Tracking
Cross-lingual event tracking from a very large number of information sources (thousands of Web sites, for example) is an open challenge. In this paper we investigate effective and scalable solutions for this problem, focusing on the use of cross-lingual information retrieval techniques to translate a small subset of the training documents, as an alternative to the conventional approach of translating all the multilingual test documents. In addition, we present a new variant of weighted pseudo-relevance feedback for adaptive event tracking. This new method simplifies the assumption and the computation in the best-known approach of this kind, yielding a better result than the latter on benchmark datasets in our evaluations.