The classification and synthesis for load characteristics is the effective way of settling the time-variation problem in composite load modeling. Based on the random process correlation theory, a new ...classification and synthesis method for dynamic load characteristics is presented. It uses the measured response space as the character vector space of load characteristics. Firstly, the measured response of each sample is standardized in time coordination; secondly, the correlation coefficients between every two samples in measured response space are computed; thirdly, the system clustering method is used to make the load characteristics classification according to the value of correlation coefficients; at last, the clustering center of each classification is gained by computing the gravity center of all the samples in this classification, and by identifying the clustering center of each load characteristics classification, the synthetic load model of each classification is gained. With a project instance, the correctness, effectiveness and convenient realization of the new method are proved.
Hybrid Columnar Compression (HCC) is probably one of the least understood of the features that are unique to Exadata. The feature was originally rolled out in a beta version of 11gR2 and was enabled ...on both Exadata and non-Exadata platforms. The production release of 11gR2 restricted the feature to Exadata platforms only. Ostensibly this decision was made because the additional processing power available on the Exadata storage servers. Because the feature is restricted to Exadata, the recent documentation refers to it as Exadata Hybrid Columnar Compression (EHCC).
Web Testing Practices Sacks, Matthew
Pro Website Development and Operations
Book Chapter
Testing a web application requires not only testing the site itself, but also looking at the various application metrics at every layer of the stack. It’s like building an aircraft: each part of the ...aircraft has to be engineered and tested for safety before it is made a part of the whole. Once each subsystem has been developed and tested, they can all be assembled into the finished product for a test flight. With such a complex system, it only makes sense to be sure you can trust the individual parts before you assume the finished product will get you off the ground.
There are many aspects to consider in appraising how well a tool accomplished the goal it was designed for. A web site is, in its base form, just such a tool. In previous chapters, we’ve discussed ...how web sites perform in accomplishing their goals in terms of technical capability (what CSS can do). In this chapter, we’ll switch gears and discuss performance in terms of how efficiently and speedily CSS can do the things you want to do with it.
All of the code we have developed so far in this book has been self-contained with no reliance on any outside services. Frequently in your web development endeavors you will need to integrate ...features that you don’t necessarily have the resources to provide. Or it simply may be that an outside service provides you with access to data you wouldn’t otherwise be able to access.
Understanding website complexity Butkiewicz, Michael; Madhyastha, Harsha V.; Sekar, Vyas
Proceedings of the 2011 ACM SIGCOMM conference on Internet measurement conference,
11/2011
Conference Proceeding
Over the years, the web has evolved from simple text content from one server to a complex ecosystem with different types of content from servers spread across several administrative domains. There is ...anecdotal evidence of users being frustrated with high page load times or when obscure scripts cause their browser windows to freeze. Because page load times are known to directly impact user satisfaction, providers would like to understand if and how the complexity of their websites affects the user experience.
While there is an extensive literature on measuring web graphs, website popularity, and the nature of web traffic, there has been little work in understanding how complex individual websites are, and how this complexity impacts the clients' experience. This paper is a first step to address this gap. To this end, we identify a set of metrics to characterize the complexity of websites both at a content-level (e.g., number and size of images) and service-level (e.g., number of servers/origins).
We find that the distributions of these metrics are largely independent of a website's popularity rank. However, some categories (e.g., News) are more complex than others. More than 60% of websites have content from at least 5 non-origin sources and these contribute more than 35% of the bytes downloaded. In addition, we analyze which metrics are most critical for predicting page render and load times and find that the number of objects requested is the most important factor. With respect to variability in load times, however, we find that the number of servers is the best indicator.
Vroom Ruamviboonsuk, Vaspol; Netravali, Ravi; Uluyol, Muhammed ...
Proceedings of the Conference of the ACM Special Interest Group on Data Communication,
08/2017
Conference Proceeding
The existing slowness of the web on mobile devices frustrates users and hurts the revenue of website providers. Prior studies have attributed high page load times to dependencies within the page load ...process: network latency in fetching a resource delays its processing, which in turn delays when dependent resources can be discovered and fetched.
To securely address the impact that these dependencies have on page load times, we present Vroom, a rethink of how clients and servers interact to facilitate web page loads. Unlike existing solutions, which require clients to either trust proxy servers or discover all the resources on any page themselves, Vroom's key characteristics are that clients fetch every resource directly from the domain that hosts it but web servers aid clients in discovering resources. Input from web servers decouples a client's processing of resources from its fetching of resources, thereby enabling independent use of both the CPU and the network. As a result, Vroom reduces the median page load time by more than 5 seconds across popular News and Sports sites. To enable these benefits, our contributions lie in making web servers capable of accurately aiding clients in resource discovery and judiciously scheduling a client's receipt of resources.
Web-QOE under real-world distractions: Two test cases Guse, Dennis; Egger, Sebastian; Raake, Alexander ...
2014 Sixth International Workshop on Quality of Multimedia Experience (QoMEX),
2014-Sept.
Conference Proceeding
Real-world usage of web browsing differs considerably from typically employed laboratory tests on single or multiple page views. Especially when using mobile devices such as smartphones or tablets, ...several sources of distraction are prevalent while browsing. In the mobile scenario, users are exposed to distracting factors like other people, traffic, announcements etc., whereas at home parallel use of TV or radio services might distract the user. To assess the impact due to context and distractions, this paper presents two studies of web browsing Quality of Experience. The studied factors of possible influence on QoE include one specific browsing task, the environment and a dedicated distraction task. The results show that, in contrast to ratings for multimedia sessions containing audio, video or speech, QoE ratings for web browsing are not affected by the considered contexts or distractions. However, it was found that the primary task for the browsing session had a significant influence on the QoE ratings regardless of the environment or distracting task.
There are many challenges in building mobile Web applications today. One of the critical challenges that the developers face is on the "performance" of the mobile Web application. With the ever ...boosting hardware on the mobile phones and tablets, the demand for the best performance on the mobile is something that the developers cannot ignore. Studies after studies have indicated that the probability of the user putting up with the mediocre performing application is very less. This paper illustrates the different techniques that the developers need to bring in to measure and optimize the performance of the mobile Web application in different layers like HTML, CSS, and Java script and also during deployment. The paper takes up a use case application, measures and baselines the performance and then applies various techniques to measure the gain/loss in performance after application of each technique.
