Web Service System Research Articles

SWS: accessing SRS sites contents through Web Services

BackgroundWeb Services and Workflow Management Systems can support creation and deployment of network systems, able to automate data analysis and retrieval processes in biomedical research. Web Services have been implemented at bioinformatics centres and workflow systems have been proposed for biological data analysis.New databanks are often developed by taking into account these technologies, but many existing databases do not allow a programmatic access. Only a fraction of available databanks can thus be queried through programmatic interfaces. SRS is a well know indexing and search engine for biomedical databanks offering public access to many databanks and analysis tools. Unfortunately, these data are not easily and efficiently accessible through Web Services.ResultsWe have developed ‘SRS by WS’ (SWS), a tool that makes information available in SRS sites accessible through Web Services. Information on known sites is maintained in a database, srsdb. SWS consists in a suite of WS that can query both srsdb, for information on sites and databases, and SRS sites. SWS returns results in a text-only format and can be accessed through a WSDL compliant client. SWS enables interoperability between workflow systems and SRS implementations, by also managing access to alternative sites, in order to cope with network and maintenance problems, and selecting the most up-to-date among available systems.ConclusionsDevelopment and implementation of Web Services, allowing to make a programmatic access to an exhaustive set of biomedical databases can significantly improve automation of in-silico analysis. SWS supports this activity by making biological databanks that are managed in public SRS sites available through a programmatic interface.

Computational origami environment on the web

We present a computing environment for origami on the web. The environment consists of the computational origami engine Eos for origami construction, visualization, and geometrical reasoning, WebEos for providing web interface to the functionalities of Eos, and web service system Scorum for symbolic computing web services. WebEos is developed using Web2.0 technologies, and provides a graphical interactive web interface for origami construction and proving. In Scorum, we are preparing web services for a wide range of symbolic computing systems, and are using these services in our origami environment. We explain the functionalities of this environment, and discuss its architectural and technological features.

A novel intelligent service selection algorithm and application for ubiquitous web services environment

It is one of most important problems to choose a most appropriate service for user from all the useable services regardless of user’s location and heterogeneous architecture of underlying software and hardware infrastructure in ubiquitous computing. In order to overcome the shortcomings of blindness and randomicity in traditional service selection algorithm, we propose a novel ANN-based (Artificial Neural Network) service selection algorithm (called the ANNSS algorithm). We adopt a novel method that according to the earlier information of the cooperation between the devices and the context information, an ANN-based evaluation standard for the service quality of service provider is given out so that user can acquire an effective guidance and choose the most appropriate service. At the same time, we improved the traditional BP algorithm based on three-term method (called the TTMBP) consisting of a learning rate (LR), a momentum factor (MF) and a proportional factor (PF) in order to satisfy the requirements of time issue in real-time system. The convergence speed and stability were enhanced by adding the proportional factor. The self-adjusting architecture method is adopted so that a moderate scale of neural network can be obtained. We have implemented the ANNSS algorithm in an actual ubiquitous web services system and fulfilled various simulations. The results of simulation show that the proposed service selection scheme is not only scalable but also efficient, and that the novel BP algorithm based on three-term has high convergence speed and good convergence stability. The novel service selection scheme superior to the traditional service selection scheme without ANNSS. The novel algorithm can exactly choose a most appropriate service in ubiquitous web services environment.

A Best Practice Guide to Resource Forecasting for Computing Systems

Recently, measurement-based studies of software systems have proliferated, reflecting an increasingly empirical focus on system availability, reliability, aging, and fault tolerance. However, it is a nontrivial, error-prone, arduous, and time-consuming task even for experienced system administrators, and statistical analysts to know what a reasonable set of steps should include to model, and successfully predict performance variables, or system failures of a complex software system. Reported results are fragmented, and focus on applying statistical regression techniques to monitored numerical system data. In this paper, we propose a best practice guide for building empirical models based on our experience with forecasting Apache web server performance variables, and forecasting call availability of a real-world telecommunication system. To substantiate the presented guide, and to demonstrate our approach in a step by step manner, we model, and predict the response time, and the amount of free physical memory of an Apache web server system, as well as the call availability of an industrial telecommunication system. Additionally, we present concrete results for a) variable selection where we cross benchmark three procedures, b) empirical model building where we cross benchmark four techniques, and c) sensitivity analysis. This best practice guide intends to assist in configuring modeling approaches systematically for best estimation, and prediction results.

Dynamic replication of web contents

The phenomenal growth of the World Wide Web has brought huge increase in the traffic to the popular web sites. Long delays and denial of service experienced by the end-users, especially during the peak hours, continues to be the common problem while accessing popular sites. Replicating some of the objects at multiple sites in a distributed web-server environment is one of the possible solutions to improve the response time/latency. The decision of what and where to replicate requires solving a constraint optimization problem, which is NP-complete in general. In this paper, we consider the problem of placing copies of objects in a distributed web server system to minimize the cost of serving read and write requests when the web servers have limited storage capacity. We formulate the problem as a 0–1 optimization problem and present a polynomial time greedy algorithm with backtracking to dynamically replicate objects at the appropriate sites to minimize a cost function. To reduce the solution search space, we present necessary conditions for a site to have a replica of an object in order to minimize the cost function. We present simulation results for a variety of problems to illustrate the accuracy and efficiency of the proposed algorithms and compare them with those of some well-known algorithms. The simulation results demonstrate the superiority of the proposed algorithms.

Automation of in-silico data analysis processes through workflow management systems

Data integration is needed in order to cope with the huge amounts of biological information now available and to perform data mining effectively. Current data integration systems have strict limitations, mainly due to the number of resources, their size and frequency of updates, their heterogeneity and distribution on the Internet. Integration must therefore be achieved by accessing network services through flexible and extensible data integration and analysis network tools. EXtensible Markup Language (XML), Web Services and Workflow Management Systems (WMS) can support the creation and deployment of such systems. Many XML languages and Web Services for bioinformatics have already been designed and implemented and some WMS have been proposed. In this article, we review a methodology for data integration in biomedical research that is based on these technologies. We also briefly describe some of the available WMS and discuss the current limitations of this methodology and the ways in which they can be overcome.

웹 서비스의 서버 구조 단순화를 통한 웹 2.0 웹서비스 성능향상

본 논문은 웹서비스의 성능 향상을 위해 Servlet 컨테이너를 제거함으로써 전형적인 웹 서비스 구현의 필수 구성요소로 요구되는 SOAP 처리를 향상시킨 모바일 웹 서비스 구조 (SMSP)를 제안한다. HTTP 상에서 SOAP을 존재하게 하여 구현 실험에 의거한 지연 수행 평가를 보여주고, 웹2.0 표준 웹서비스 시스템의 성능 평가를 하였다. 본 논문에서 제안하는 모델은 웹 2.0 의 웹서비스 시스템의 통신 오버헤드와 메시지를 처리하는 시간, 서버 오버헤드를 감소시키면서, 표준 웹 서비스 프로토콜을 완전하게 지원할 수 있다. In this paper, we are to overcome the latency problem of current Web 2.0 Web Services system. To overcome the standard mobile web services implementation, a SOAP message processing system (SMSP) was proposed in which the SOAP request and response messages are directly processed without using Servlet engine. Our system can completely support standard Web Services protocol, reducing communication overhead, message processing time, and server overload.

Biowep: a workflow enactment portal for bioinformatics applications

BackgroundThe huge amount of biological information, its distribution over the Internet and the heterogeneity of available software tools makes the adoption of new data integration and analysis network tools a necessity in bioinformatics. ICT standards and tools, like Web Services and Workflow Management Systems (WMS), can support the creation and deployment of such systems. Many Web Services are already available and some WMS have been proposed. They assume that researchers know which bioinformatics resources can be reached through a programmatic interface and that they are skilled in programming and building workflows. Therefore, they are not viable to the majority of unskilled researchers. A portal enabling these to take profit from new technologies is still missing.ResultsWe designed biowep, a web based client application that allows for the selection and execution of a set of predefined workflows. The system is available on-line. Biowep architecture includes a Workflow Manager, a User Interface and a Workflow Executor. The task of the Workflow Manager is the creation and annotation of workflows. These can be created by using either the Taverna Workbench or BioWMS. Enactment of workflows is carried out by FreeFluo for Taverna workflows and by BioAgent/Hermes, a mobile agent-based middleware, for BioWMS ones. Main workflows' processing steps are annotated on the basis of their input and output, elaboration type and application domain by using a classification of bioinformatics data and tasks. The interface supports users authentication and profiling. Workflows can be selected on the basis of users' profiles and can be searched through their annotations. Results can be saved.ConclusionWe developed a web system that support the selection and execution of predefined workflows, thus simplifying access for all researchers. The implementation of Web Services allowing specialized software to interact with an exhaustive set of biomedical databases and analysis software and the creation of effective workflows can significantly improve automation of in-silico analysis. Biowep is available for interested researchers as a reference portal. They are invited to submit their workflows to the workflow repository. Biowep is further being developed in the sphere of the Laboratory of Interdisciplinary Technologies in Bioinformatics – LITBIO.

Modeling the Measurements of QoS Requirements in Web Service Systems

The new technology of Web services is beginning to impact the global business approaches and trends in which the services are being offered and consumed. The advancement of Web services and its wide spread use require that its quality of service (QoS) components to be highly dependable and robust. It is clear that one of the major inevitable challenges facing the business organizations today is to provide adequate QoS aspects for Web services. This paper gathers together the various techniques that can be used for measuring and optimizing the major QoS requirements for Web services proposed by the World Wide Consortium (W3C), while presenting a methodology to build QoS-aware Web services. A software model was designed and implemented to test a Web service and perform the experiments to quantitatively measure the QoS requirements involved in a Web service. Various modeling tests and experiments were designed and conducted to illustrate the proposed QoS measurement metrics. The techniques discussed in this paper can be incorporated into the planning, design, implementation, deployment, operational and maintenance phases during a Web service development lifecycle.

An XML-Based Networking Method for Connecting Distributed Anthropometric Databases

Anthropometric data are used by numerous types of organizations for health evaluation, ergonomics, apparel sizing, fitness training, and many other applications. Data have been collected and stored in electronic databases since at least the 1940s. These databases are owned by many organizations around the world. In addition, the anthropometric studies stored in these databases often employ different standards, terminology, procedures, or measurement sets. To promote the use and sharing of these databases, the World Engineering Anthropometry Resources (WEAR) group was formed and tasked with the integration and publishing of member resources. It is easy to see that organizing worldwide anthropometric data into a single database architecture could be a daunting and expensive undertaking. The challenges of WEAR integration reflect mainly in the areas of distributed and disparate data, different standards and formats, independent memberships, and limited development resources. Fortunately, XML schema and web services provide an alternative method for networking databases, referred to as the Loosely Coupled WEAR Integration. A standard XML schema can be defined and used as a type of Rosetta stone to translate the anthropometric data into a universal format, and a web services system can be set up to link the databases to one another. In this way, the originators of the data can keep their data locally along with their own data management system and user interface, but their data can be searched and accessed as part of the larger data network, and even combined with the data of others. This paper will identify requirements for WEAR integration, review XML as the universal format, review different integration approaches, and propose a hybrid web services/data mart solution.

Object Grouping and Replication on a Distributed Web Server System

Object replication is a well-known technique to improve performance of a distributed Web-server system. This article first presents an algorithm to group correlated Web objects that are most likely to be requested by a given client in a single session so that they can be replicated together, preferably, on the same server. A centralized object replication algorithm is then proposed to replicate the object groups to a cluster of Web-server systems in order to minimize the user’s perceived latency, which is subject to certain constraints. Due to the dynamic nature of Web content and users’ access patterns, a distributed object replication algorithm also is proposed where each site locally replicates the object groups based on the local access patterns. The performance of the proposed algorithms is compared with three well-known algorithms, and the results are reported. The results demonstrate the superiority of the proposed algorithms.

An auxiliary server threshold queueing model and its application to the operational characteristics of web server system

This paper analyzes an auxiliary server queueing model in which secondary servers are added to the main server(s) when the queue length exceeds some predetermined threshold value at the main queue. We model this system by the level-dependent quasi-birth-death (QBD) process and develop computation algorithms. We apply this model to the web-server system to explore some specific operational characteristics and draw some useful conclusions.

Intention Interpretation for Service Request Using User Models

A method to extract user intention from the service request string entered by the user is proposed and applied in semantic Web service systems. Imprecise user intentions are modeled with computable goal models. Three kinds of background knowledge are used when extracting the user intention: domain ontology, goal structure, and user profiles. Domain ontology is constructed to represent the concepts in the application domain, the goal structure indicates the system capabilities, and the user profiles are for the intelligent system to infer the user's preference. The input terms will be parsed into different word sense sets. With the domain ontology, possible senses of the terms will be identified. The goal structure is used for mapping the user's requests to system capabilities. The user models will be used to aid the selection of a personalized candidate goal model for representing the user intention. The system can base on the selected goal model to generate and perform a series of actions for achieving the goal model.

Web-based interactive visualization of 3D video mosaics using X3D standard

We present a method of 3D image mosaicing for real 3D representation of roadside buildings, and implement a Web-based interactive visualization environment for the 3D video mosaics created by 3D image mosaicing. The 3D image mosaicing technique developed in our previous work is a very powerful method for creating textured 3D-GIS data without excessive data processing like the laser or stereo system. For the Web-based open access to the 3D video mosaics, we build an interactive visualization environment using X3D, the emerging standard of Web 3D. We conduct the data preprocessing for 3D video mosaics and the X3D modeling for textured 3D data. The data preprocessing includes the conversion of each frame of 3D video mosaics into concatenated image files that can be hyperlinked on the Web. The X3D modeling handles the representation of concatenated images using necessary X3D nodes. By employing X3D as the data format for 3D image mosaics, the real 3D representation of roadside buildings is extended to the Web and mobile service systems.

An expert system approach to improving stability and reliability of web service

In recent years, Internet service has become an important issue that attracts the researchers from both computer science and communication fields. Although many systems were proposed to support network-based e-activities, e.g., e-learning and e-commerce, few of them took into consideration web server management issues that are critical to the stability and reliability for providing Internet service. To cope with these problems, this study proposes a novel approach to eliciting and integrating system management knowledge from experienced system managers. An expert system for monitoring web servers has been implemented based on the novel approach; moreover, an experiment on an educational system has shown the superiority of the expert system in predicting and handling possible malfunctions or anomalies of web service systems.

Assessing the Health of Open Source Communities

Before contributing to a free or open source software project, understand the developers, leaders, and active users behind it. The computing world lauds many Free/Libre and open source software offerings for both their reliability and features. Successful projects such as the Apache httpd Web server and Linux operating system kernel have made FLOSS a viable option for many commercial organizations. While FLOSS code is easy to access, understanding the communities that build and support the software can be difficult. Despite accusations from threatened proprietary vendors, few continue to believe that open source programmers are all amateur teenaged hackers working alone in their bedrooms. But neither are they all part of robust, well-known communities like those behind Apache and Linux.

News: data-driven enterprise - slouching toward the semantic Web

Many organizations are still trying to figure out how to build a mostly object-oriented Web services system. In explaining the semantic Web's enterprise possibilities, the author emphasizes the benefits of direct access to the data within applications rather than integrating the applications themselves. Some industry observers still see the semantic Web as a theoretician's dream. Enterprises are still trying to figure out how to integrate applications via Web services and service-oriented architectures, so asking them to begin drawing up semantic Web capable taxonomies anytime soon isn't realistic. The knowledge sharing that would entice enterprises would allow relational databases to directly import ontologies and rules just as easily as they use standard SQL insert, update, and delete statements. Ontologies can act as the glue between multiple information sources, providing a consistent view of all the information, augmenting it and filling in the gaps. The best route for success will be to stop emphasizing what the semantic Web might do in the future and work instead on practical steps to improve the architecture.

Fault tolerance in web services

This paper demonstrates how to design a fault tolerant web application that relies on an affordable redundancy in data and function using Simple Object Access Protocol (SOAP). The proposed approach relies on a Single-Version fault tolerance model without using multiple versions or the N-Version fault tolerance model. The work aims to design a more dependable and reliable Web Service system at no extra cost on multiple versions.

Fault tolerance in web services

This paper demonstrates how to design a fault tolerant web application that relies on an affordable redundancy in data and function using Simple Object Access Protocol (SOAP). The proposed approach relies on a Single-Version fault tolerance model without using multiple versions or the N-Version fault tolerance model. The work aims to design a more dependable and reliable Web Service system at no extra cost on multiple versions.

Performance management for cluster-based web services

We present an architecture and prototype implementation of a performance management system for cluster-based web services. The system supports multiple classes of web services traffic and allocates server resources dynamically so to maximize the expected value of a given cluster utility function in the face of fluctuating loads. The cluster utility is a function of the performance delivered to the various classes, and this leads to differentiated service. In this paper, we will use the average response time as the performance metric. The management system is transparent: it requires no changes in the client code, the server code, or the network interface between them. The system performs three performance management tasks: resource allocation, load balancing, and server overload protection. We use two nested levels of management. The inner level centers on queuing and scheduling of request messages. The outer level is a feedback control loop that periodically adjusts the scheduling weights and server allocations of the inner level. The feedback controller is based on an approximate first-principles model of the system, with parameters derived from continuous monitoring. We focus on SOAP-based web services. We report experimental results that show the dynamic behavior of the system.