On the Design of Web Services: SOAP vs. REST

The purpose of this thesis is to compare the performance characteristics of Simple Object Access Protocol (SOAP) and Representational State Transfer (REST), which are methods of supporting interactions among Web services. They differ in both context and usage; SOAP is a protocol while REST is architecture. SOAP is a well-developed protocol used in the Web industry and is standardized by the World Wide Web Consortium (W3C). REST is the outcome of Dr. Roy Thomas Fielding’s 2000 PhD dissertation, “Architectural Styles and the Design of Network-Based Software Architecture.” REST is gaining in popularity due to its simplicity, scalability, and architectural dependence on the World Wide Web. Major software companies, such as Google and Amazon, among others, have started using REST. The main difference between the two methods is SOAP is a tightly coupled system, whereas REST is a loosely coupled system; both have advantages and disadvantages. We built SOAP and REST based Web services that performed the GET, POST, PUT, and DELETE functions on a database. We utilized response time and throughput metrics to compare the performance of these Web services. In comparing the two technologies, we found REST was considerably faster, compared to SOAP, because the response times of REST were better than those of SOAP. As an ancillary outcome, we found building Web services using SOAP was easier, due to considerable tool support, whereas developing Web services using REST was time consuming, as it provides no tool support

Towards area-wide traffic monitoring-applications derived from probe vehicle data

Comprehensive, up-to-date traffic monitoring is the basis for mobility information and traffic management systems. However, conventional stationary traffic data measurements are hardly able to provide the necessary data for an area-wide monitoring and cannot deliver enough information for many traffic related services. Therefore an al-ternative approach using positioning data of commercial vehicle fleets for traffic monitoring issues has been established. This paper surveys differnt prototype applications based on this probe vehicle data. Continuous monitoring and information of traffic situation via the World Wide Web accomplished by jam detection and highlighting is the basic service. Further on, vehicle route guidance systems using current and historic data achieve superior performance. Such guidance systems have been tested as modules for dynamic navigation and fleet disposition system. Finally a method to derive digital road maps and street characteristics from positioning data is presented

WASEF: Web Acceleration Solutions Evaluation Framework

The World Wide Web has become increasingly complex in recent years. This complexity severely affects users in the developing regions due to slow cellular data connectivity and usage of low-end smartphone devices. Existing solutions to simplify the Web are generally evaluated using several different metrics and settings, which hinders the comparison of these solutions against each other. Hence, it is difficult to select the appropriate solution for a specific context and use case. This paper presents Wasef, a framework that uses a comprehensive set of timing, saving, and quality metrics to evaluate and compare different web complexity solutions in a reproducible manner and under realistic settings. The framework integrates a set of existing state-of-the-art solutions and facilitates the addition of newer solutions down the line. Wasef first creates a cache of web pages by crawling both landing and internal ones. Each page in the cache is then passed through a web complexity solution to generate an optimized version of the page. Finally, each optimized version is evaluated in a consistent manner using a uniform environment and metrics. We demonstrate how the framework can be used to compare and contrast the performance characteristics of different web complexity solutions under realistic conditions. We also show that the accessibility to pages in developing regions can be significantly improved, by evaluating the top 100 global pages in the developed world against the top 100 pages in the lowest 50 developing countries. Results show a significant difference in terms of complexity and a potential benefit for our framework in improving web accessibility in these countries.Comment: 15 pages, 4 figure

Development of a Novel Media-independent Communication Theology for Accessing Local & Web-based Data: Case Study with Robotic Subsystems

Realizing media independence in today’s communication system remains an open problem by and large. Information retrieval, mostly through the Internet, is becoming the most demanding feature in technological progress and this web-based data access should ideally be in user-selective form. While blind-folded access of data through the World Wide Web is quite streamlined, the counter-half of the facet, namely, seamless access of information database pertaining to a specific end-device, e.g. robotic systems, is still in a formative stage. This paradigm of access as well as systematic query-based retrieval of data, related to the physical enddevice is very crucial in designing the Internet-based network control of the same in real-time. Moreover, this control of the end-device is directly linked up to the characteristics of three coupled metrics, namely, ‘multiple databases’, ‘multiple servers’ and ‘multiple inputs’ (to each server). This triad, viz. database-input-server (DIS) plays a significant role in overall performance of the system, the background details of which is still very sketchy in global research community. This work addresses the technical issues associated with this theology, with specific reference to formalism of a customized DIS considering real-time delay analysis. The present paper delineates the developmental paradigms of novel multi-input multioutput communication semantics for retrieving web-based information from physical devices, namely, two representative robotic sub-systems in a coherent and homogeneous mode. The developed protocol can be entrusted for use in real-time in a complete user-friendly manner

The Network Effects of Prefetching

Prefetching has been shown to be an effective technique for reducing user perceived latency in distributed systems. In this paper we show that even when prefetching adds no extra traffic to the network, it can have serious negative performance effects. Straightforward approaches to prefetching increase the burstiness of individual sources, leading to increased average queue sizes in network switches. However, we also show that applications can avoid the undesirable queueing effects of prefetching. In fact, we show that applications employing prefetching can significantly improve network performance, to a level much better than that obtained without any prefetching at all. This is because prefetching offers increased opportunities for traffic shaping that are not available in the absence of prefetching. Using a simple transport rate control mechanism, a prefetching application can modify its behavior from a distinctly ON/OFF entity to one whose data transfer rate changes less abruptly, while still delivering all data in advance of the user's actual requests