원격 감시제어를 위한 웹 서비스 S/W 플랫폼 설계 및 구현

Native Web communication protocols are the pivotal components of Web services, applications and systems. In particular, HTTP is a de facto protocol standard used in almost all Web services and systems. Consequently, it is one of the crucial protocols responsible for the performance of Web services and systems. HTTP/1.1 has been successfully deployed in Web services and systems for the last two decades. However, one of the most significant issues with HTTP/1.1 is the Round Trip Time and Web latency. To resolve this issue, two successor protocols SPDY and HTTP/2 have been developed recently, with some studies suggesting that SPDY improved the performance of Web services and systems, whilst some did not find significant improvements in the performance. HTTP/2 is a relatively new protocol and has yet to be tested with any rigour. Therefore, it is important to investigate the effects of these two enhanced protocols SPDY and HTTP/2 on the performance of Web services and systems. This paper conducts a number of practical investigations to evaluate the performance of Web services and systems with and without the support of SPDY and HTTP/2 protocols at the client and server. This study investigates the impact of SPDY and HTTP/2 on the overall performance of Web services and systems from the end-user's perspective.

High-performance Web servers are essential to meet the growing demands of the Internet and large-scale intranets. Satisfying these demands requires a thorough understanding of key factors affecting Web server performance. This paper presents empirical analysis illustrating how dynamic and static adaptivity can enhance Web server performance. Two research contributions support this conclusion. First, the paper presents results from a comprehensive empirical study of Web servers (such as Apache, Netscape Enterprise, PHTTPD, Zeus, and JAWS) over high-speed ATM networks. This study illustrates their relative performance and precisely pinpoints the server design choices that cause performance bottlenecks. Once network and disk I/O overheads are reduced to negligible constant factors, the main determinants of Web server performance are its protocol processing path and concurrency strategy. Moreover no single strategy performs optimally for all load conditions and traffic types. Second, we describe the design techniques and optimizations used to develop JAWS, our high-performance adaptive Web server. JAWS is an object-oriented Web server that was explicitly designed to alleviate the performance bottlenecks we identified in existing Web servers. The performance optimizations used in JAWS include adaptive prespawned threading, fixed headers, cached date processing, and file caching. In addition, JAWS uses a novel software architecture that substantially improves its portability and flexibility, relative to other Web servers.

Towards a context-based multi-type policy approach for Web services composition

Background/Objectives: The primary objective of the study is to evaluate the performance of Composite Web Service based on the parameters relating to Quality of Service by using statistical methodologies. Methods/Statistical Analysis: By using Web Service Crawler Engine we have collected data on eleven parameters of interest from a more number of Web Services. Among the eleven parameters we have selected six parameters of importance using the sampling of thirty Web Services. We have constructed the weight matrix for the parameters. By using Web Services Relevancy Function ranking has been done for three different scenarios. Using Spearman's Rank Correlation Coefficient we have compared the scenarios. Findings: The graphical representation of the three scenarios shows varying pattern. The Spearman's Rank Correlation coefficient of the Web Services Relevancy Function varied widely among the sampled Web Services. F-Test revealed that there are no significant differences in respect of weights of Quality of Web Services for three different scenarios. We concluded that weight assigned for Quality of Service parameters in Scenario I is preferred than the scenarios II and III through the evaluations. Application/Improvements: The technique developed in this research paper can be applied for the comparison of Web Services during discovery to enhance the performance of the Composite Web Service.

Data Acquisition and Interface Technology is a compulsory course for the major of measurement and control technology and instrument in Southwest Petroleum University, and it is a basic course combining theory and practice closely. The traditional experiment teaching is limited by various conditions. Students can only complete the specific experiment content with limited experiment equipment in limited time and place. It is an effective way to solve the above problems by introducing virtual simulation technology to construct the remote measure and control experiment platform to carry on the reform of the traditional experiment teaching mode. The remote measurement and control platform uses virtual technology to form the test function into a software module with image-realistic panel controls, to complete the test and processing tasks as if doing experiments in the laboratory, to move the experiment teaching into the classroom, to move into the network and life, and to realize the perfect fusion of theory and practice. It has been proved that the application of the remote measurement and control platform in the experimental teaching of the course of Data Acquisition and Interface Technology can improve the teaching effect. Moreover, the cost is low and the efficiency is high, so that students cannot be limited by time and space, improve their self-learning ability and practical innovation ability, which is of great significance in the teaching of the course of measurement and control technology.

PurposeWeb services promise a step change in business‐to‐business application models and practices. But how do we measure web services' performance? Because web services are so new, and implementations so few, the purpose of this paper is to take internet performance as a proxy for web services performance.Design/methodology/approachThe authors surveyed 106 e‐business SMEs to identify key drivers for internet performance, and then predicted web services performance.FindingsSurprisingly, it was found that while business resources and IT resources positively impact internet performance, dynamic capabilities do not. Also, there appear to be significant firm size effects.Originality/valueThe implications of these findings for the strategic management of web services are discussed, and in particular, managers' need to balance resources and capabilities in volatile business environments.

On the performance of web services, google cloud messaging and firebase cloud messaging

Background: The COVID-19 pandemic created an urgent need to act to reduce the spread of the virus and alleviate congestion from healthcare services, protect healthcare providers, and help them maintain satisfactory quality and safety of care. Remote COVID-19 monitoring platforms emerged as potential solutions.Objective: The purpose of this study was to evaluate the capacity and contribution of two different platforms used to remotely monitor patients with COVID-19 to maintain quality, safety, and patient engagement in care, as well as their acceptability, usefulness, and user-friendliness from the user's perspective. The first platform is focused on telecare phone calls (Telecare-Covid), and the second is a telemonitoring app (CareSimple-Covid).Methods: We performed a cross-sectional study. The data were collected through a phone survey from May to August 2020. Data were analyzed using descriptive statistics and t-test analysis. Participants' responses and comments on open-ended questions were analyzed using content analysis to identify certain issues and challenges and potential avenues for improving the platforms.Results: Fifty one patients participated in the study. Eighteen participants used the CareSimple-Covid platform and 33 participants used the Telecare-Covid platform. Overall, the satisfaction rate for quality and safety of care for the two platforms was 80%. Over 88% of the users on each platform considered the platforms' services to be engaging, useful, user-friendly, and appropriate to their needs. The survey identified a few significant differences in users' perceptions of each platform: empathy toward users and the quality and safety of the care received were rated significantly higher on the CareSimple-Covid platform than on the Telecare-Covid platform. Users appreciated four aspects of these telehealth approaches: (1) the ease of access to services and the availability of care team members; (2) the user-friendliness of the platforms; (3) the continuity of care provided, and (4) the wide range of services delivered. Users identified some technical limitations and raised certain issues, such as the importance of maintaining human contact, data security, and confidentiality. Improvement suggestions include promoting access to connected devices; enhancing communications between institutions, healthcare users, and the public on confidentiality and personal data protection standards; and integrating a participatory approach to telehealth platform development and deployment efforts.Conclusion: This study provides preliminary evidence that the two remote monitoring platforms are well-received by users, with very few significant differences between them concerning users' experiences and views. This type of program could be considered for use in a post-pandemic era and for other post-hospitalization clienteles. To maximize efficiency, the areas for improvement and the issues identified should be addressed with a patient-centered approach.

Two networked embedded systems for existent power equipment are designed in this paper to achieve the goal of remote control and monitoring. Since the basic requirement of industrial control and monitoring systems is the response time; therefore, time constraint is the first consideration in designing networked embedded systems. Telnet and Web server are the commonly used Internet functions for embedded systems. The embedded Web server based system is definitely the better choice for power equipment control and monitoring. However, due to the response time constraint, memory capacity and processing power of embedded systems, a Telnet based system is also presented in this paper. Since RS232 is the most popular communication media for existent power equipment; the developed embedded system is deigned to communicate with the existent power equipment by RS232. After the data retrieved from the power equipment, the designed system can transmit those data to remote control center via the Internet. The experimental platform shown in this paper is a Samsung S3C4510-based embedded system. The embedded system features uCLinux operating system; therefore, the design and implementation of these proposed networked systems could be more effective. Experimental results show that the designed networked embedded systems can be integrated into power equipment effectively.

In modem industrial and agricultural production, the working temperature change reflects the operating status of equipments and change of many physical characteristics, so the temperature is an important parameter, which needs to be monitored, especially in the severe environment. The workers can make right judgments and operation by a temperature monitor. So it is the most effective and most economical means of equipment safety monitoring. A temperature remote monitoring embedded system platform is designed in the paper. And the embedded microprocessor AT91SAM7X256 is used as CPU of the system. The system realizes real-time remote data collection monitoring and storage through protocol data conversion of the CAN bus and RS232 bus of the distributed temperature acquisition node. At the same time, the system realizes the remote temperature monitoring and control through TCP/IP Industrial Ethernet Web. The system platform can be applied to certain equipments of the power system, intelligent agriculture remote monitoring, intelligent furniture monitoring, intelligent warehouse monitoring and so on. The temperature measurement accuracy is within 0.5°C. The system is reliable and stable. And there are not communication failures. So it has very good social prospects.

The advent of Web technology has made Web servers core elements of future communication networks. Although the amount of traffic that Web servers must handle has grown explosively during the last decade, the performance limitations and the proper tuning of Web servers are still not well understood. In this paper we present an end-to-end queueing model for the performance of Web servers, encompassing the impacts of client workload characteristics, server harware/software configuration, communication protocols, and interconnect topologies. The model has been implemented in a simulation tool, and performance predictions based on the model are shown to match very well with the performance of a Web server in a test lab environment. The simulation tool forms an excellent basis for development of a Decision Support System for the configuration tuning and sizing of Web servers.

Current software has more flexibility and generality in the design for the distributed application, unfortunately, which gives rise to some efficiency problems in the implementation. In order to improve the performance of Web services, this paper introduces partial evaluation into distributed environments. Partial evaluation specializes generic programs into specific realization. We propose the partial evaluation for object-oriented programs and implement the distributed partial evaluation based on the specialization of Java Byte Code. The experiment results show that partial evaluation is effective to optimize Web services. The integration of partial evaluation with Web services facilitates programs more generality and scalability.

Ajax-based web applications are designed to mimic more traditional desktop applications and require quick response times from the underlying Web services. However, since availability and performance of Web services cannot be guaranteed, response time and overall performance of Ajax-based applications can vary. In this paper we describe a framework for developing autonomic self-healing Web service-based applications that rely on the notion of differentiated services (i.e., services that provide common behavior with variable quality of service) in order to maintain required performance characteristics. We present the expected impact of the framework through the use of a theoretical QN model, demonstrate the framework with an example, and provide an evaluation of the technique.

The exponential growth of Web service makes building high-quality service-oriented systems an urgent and crucial research problem. Performance of the service-oriented systems highly depends on the remote Web services as well as the unpredictability of the Internet. Performance prediction of service-oriented systems is critical for automatically selecting the optimal Web service composition. Since the performance of Web services is highly related to the service status and network environments which are variable over time, it is an important task to predict the performance of service-oriented systems at runtime. To address this critical challenge, this chapter proposes an online performance prediction framework, called OPred, to provide personalized service-oriented system performance prediction efficiently. Based on the past usage experience from different users, OPred builds feature models and employs time series analysis techniques on feature trends to make performance prediction. The results of large-scale real-world experiments show the effectiveness and efficiency of OPred.

Chapter 11 - Web Services