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CLEAR: a Credible Live Evaluation Method of Website Archivability, iPRES2013

Abstract: Web archiving is crucial to ensure that cultural, scientific and social heritage on the web remains accessible and usable over time. A key aspect of the web archiving process is optimal data extraction from target websites. This procedure is difficult for such reasons as, website complexity, plethora of underlying technologies and ultimately the open-ended nature of the web. The purpose of this work is to establish the notion of Website Archivability (WA) and to introduce the Credible Live Evaluation of Archive Readiness (CLEAR) method to measureWA for any website. Website Archivability captures the core aspects of a website crucial in diagnos-
ing whether it has the potentiality to be archived with com-
pleteness and accuracy. An appreciation of the archivability of a web site should provide archivists with a valuable tool when assessing the possibilities of archiving material and influence web design professionals to consider the implications of their design decisions on the likelihood could be archived.
A prototype application,, has been established to demonstrate the viabiity of the proposed method for assessing Website Archivability.

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CLEAR: a Credible Live Evaluation Method of Website Archivability, iPRES2013

  1. 1. CLEAR: a Credible Live Evaluation Method of Website Archivability Vangelis Banos1, Yunhyong Kim2, Seamus Ross2, Yannis Manolopoulos1 1Department of Informatics, Aristotle University, Thessaloniki , Greece 2University of Glasgow, United Kingdom ARCHIVEREADY.COM
  2. 2. 2 Table of Contents 1. Problem definition and related work, 2. Our contributions, 3. Website Archivability, 4. CLEAR: A Credible Live Method to Evaluate Website Archivability, 5. Demonstration:, 6. Limitations and Future Work.
  3. 3. Problem definition • Web content acquisition is a critical step in the process of web archiving; • If the initial Submission Information Package lacks completeness and accuracy for any reason (e.g. missing or invalid web content), the rest of the preservation processes are rendered useless; • There is no guarantee that web bots dedicated to retrieving website content can access and retrieve it successfully; • Web bots face increasing difficulties in harvesting websites. 3
  4. 4. 4 • After web harvesting, administrators review manually the content and endorse or reject the harvested material. • Web harvesting is automated while Quality Assurance (QA) is manual. • Efforts to deploy crowdsourced techniques to manage QA provide an indication of how significant the bottleneck is. Problem definition
  5. 5. Inspired by our work at 5 There is a need for a method to assess website archive readiness in order to support web archiving workflow. building a blog preservation software platform
  6. 6. 6 1. the introduction of the notion of Website Archivability, 2. the definition of the Credible Live Evaluation of Archive Readiness (CLEAR) method to measure Website Archivability 3., a web application which implements the proposed method. Our Contributions
  7. 7. 7 1. Mechanism to improve the quality of web archives. 2. Expand and optimize the knowledge and practices of web archivists, supporting them in their decision making, and risk management. 3. Standardize the web aggregation practices of web archives, especially QA. 4. Foster good practices in web development, make sites more amenable to harvesting, ingesting, and preserving. 5. Raise awareness among web professionals regarding preservation. Our Aims
  8. 8. Website Archivability ? What is Website Archivability captures the core aspects of a website crucial in diagnosing whether it has the potentiality to be archived with completeness and accuracy. Attention! it must not be confused with website dependability, reliability, availability, safety, security, survivability, maintainability.
  9. 9. CLEAR: A Credible Live Method to Evaluate Website Archivability • An approach to producing on-the-fly measurement of Website Archivability, • Web archives communicate with target websites via standard HTTP, • Information such as file types, content and transfer errors could be used to support archival decisions, • We combine this kind of information with an evaluation of the website's compliance with recognised practices in digital curation, • We generate a credible score representing the archivability of target websites. 9
  10. 10. 10 Accessibility Cohesion Standards Compliance Performance Metadata CLEAR: A Credible Live Method to Evaluate Website Archivability
  11. 11. 11 Website attributes evaluated using CLEAR
  12. 12. 12 C L E A R • The method can be summarised as follows: 1. Perform specific Evaluations on Website Attributes, 2. In order to calculate each Archivability Facet’s score, • Scores range from (0 – 100%), • Not all evaluations are equal, if an important evaluation fails, score = 0, if a minor evaluation fails, score = 50% 3. Producing the final Website Archivability as the sum all Facets’ scores.
  13. 13. Accessibility 13
  14. 14. Accessibility • A website is considered accessible only if web crawlers are able to visit its home page, traverse its content and retrieve it via standard HTTP requests. 14
  15. 15. Accessibility 15 Facet Evaluation Rating Total Accessibility No RSS feed 50% 50% No robots.txt 50% No sitemap.xml 0% 6 links, all valid 100% Website Archivability evaluation on 23rd April 2013
  16. 16. Cohesion 16
  17. 17. Cohesion • Relevant to: • Efficient operation of web crawlers, • Management of dependancies with digital curation. • If files constituting a single website are dispersed across different web locations, the acquisition and ingest is likely to risk suffering if one or more web locations fail. • Changes that occur outside the website are not going to affect it if it does not use 3rd party resources. 17
  18. 18. Cohesion 18 Facet Evaluation Rating Total Cohesion 1 external and no internal scripts 0% 70% 4 local and 1 external images 80% No proprietary (Quicktime & Flash) files 100% 1 local CSS file 100% Website Archivability evaluation on 23rd April 2013
  19. 19. Metadata 19
  20. 20. Metadata • The adequate provision of metadata has been a continuing concern within digital curation. • The lack of metadata impairs the archive’s ability to manage, organise, re trieve and interact with content effectively. 20
  21. 21. Metadata 21 Facet Evaluation Rating Total Metadata Meta description found 100% 87% HTTP Content type 100% HTTP Page expiration not found 50% HTTP Last-modified found 100% Website Archivability evaluation on 23rd April 2013
  22. 22. Performance 22
  23. 23. Performance Performance is an important aspect of web archiving. The throughput of data acquisition of a web spider directly affects the number and complexity of web resources it is able to process. 23 Facet Evaluation Rating Total Performance Average network response time is 0.546ms 100% 100% Website Archivability evaluation on 23rd April 2013
  24. 24. Standards Compliance 24
  25. 25. Standards Compliance • Compliance with standards is a recurring theme in digital curation practices. It is recommended that for digital resources to be preserved they need to be represented in known and transparent standards. 25
  26. 26. Standards Compliance 26 Facet Evaluation Rating Total Standards Compliance 1 Invalid CSS file 0% 87% Invalid HTML file 0% Meta description found 100% No HTTP Content encoding 50% HTTP Content Type found 100% HTTP Page expiration found 100% HTTP Last-modified found 100% No Quicktime or Flash objects 100% 5 images found and validated with JHOVE 100% Website Archivability evaluation on 23rd April 2013
  27. 27. iPRES 2013 Website Archivability Evaluation 27 Facet Rating Website Archivability Accessibility 50% 77% Cohesion 70% Standards Compliance 77% Metadata 87% Performance 100%
  28. 28. Demonstration - Web application implementing CLEAR, - Web interface & also Web API in JSON, - Running on Linux, Python, Nginx, Redis, Mysql. 28
  29. 29. 29
  30. 30. Impact 30 1. Web professionals - evaluate the archivability of their websites in an easy but thorough way, - become aware of web preservation concepts, - embrace preservation-friendly practices. 2. Web archive operators - make informed decisions on archiving websites, - perform large scale website evaluations with ease, - automate web archiving Quality Assurance, - minimise wasted resources on problematic websites.
  31. 31. 31 Limitations & Future Work 1. Not optimal to treat all Archivability Facets as equal. 2. Evaluating a single website page, based on the assumption that web pages from the same website share the same components and standards. Sampling would be necessary. 3. Certain classes and specific types of errors create lesser or greater obstacles to website acquisition and ingest than others. The method needs to be enhanced to reflect this differential valuing of error classes and types.
  32. 32. THANK YOU Vangelis Banos Web: Email: ANY QUESTIONS? 32 The research leading to these results has received funding from the European Commission Framework Programme 7 (FP7), BlogForever project, grant agreement No.269963.