Wednesday, November 12, 2008
week 10 muddiest point
Is there any chance that we could have some sort of lab session and go over how to use Greenstone in the lab?
Friday, November 7, 2008
reading notes, week 10
Arms ch. 8
In discussing the usability of a computer system, it is easy to focus on the design of the interface between the user and the computer, but usability is a property of the total system. All the components must work together smoothly to create an effective and convenient digital library, for both the patrons, and for the librarians and systems administrators.
In any computer system, the user interface is built on a conceptual model that describes the manner in which the system is used.
The introduction of browsers, notably Mosaic in 1993, provided a stimulus to the quality of user interfaces for networked applications.
Mobile code gives the designer of a web site the ability to create web pages that incorporate computer programs
Interface design is partly an art, but a number of general principles have emerged from recent research. Consistency is important to users, in appearance, controls, and function. Users need feedback; they need to understand what the computer system is doing and why they see certain results. They should be able to interrupt or reverse actions. Error handling should be simple and easy to comprehend. Skilled users should be offered shortcuts, while beginners have simple, well-defined options. Above all the user should feel in control.
Research into functional design provides designers with choices about what functions belong on which of the various computers and the relationships between them.
A presentation profile is an interesting concept which has recently emerged. Managers of a digital library associate guidelines with stored information. The guidelines suggest how the objects might be presented to the user. For example, the profile might recommend two ways to render an object, offering a choice of a small file size or the full detail.
Few computer systems are completely reliable and digital libraries depend upon many subsystems scattered across the Internet
Kling and Elliott
"Systems usability" refers to how well people can exploit a computer system's intended functionality. Usability can characterize any aspect of the ways that people interact with a system, even its installation and maintenance.
wo key forms of DL usability - interface and organizational. The interface dimensions are centered around an individual's effective acclimation to a user interface, while the organizational dimensions are concerned with how computer systems can be effectively integrated into work practices of specific organizations.
interface usability dimensions:
"Design for usability" is a new term that refers to the design of computer systems so that they can be effectively integrated into the work practices of specific organizations.
The usability engineering life cycle model includes these stages proposed as a paradigm for companies to follow:
Saracevic:
Usability has been used widely in digital library evaluation, but there is no uniform definition of
what does it cover in digital library context. Usability is a very general criterion that covers a lot
of ground and includes many specific criteria – it is a meta term. ISO defines usability “as the
extent to which a product can be used by specified users to achieve specified goals with
effectiveness, efficiency and satisfaction in a specified context of use"
users have many difficulties with digital libraries, such as:
– they usually do not fully understand them
– they hold different conception of a digital library from operators or designers
– they lack familiarity with the range of capabilities, content and interactions
provided by a digital library.
– they often engage in blind alley interactions
in use, more often than not, digital library users and digital libraries are in an
adversarial position
The ultimate evaluation of digital libraries will revolve around assessing transformation of their
context – determining possible enhancing changes in institutions, learning, scholarly publishing,
disciplines, small worlds and ultimately society due to digital libraries.
Sheiderman and Plaisant
Human-Computer Interaction
Requirements analysis:
1- ascertain user needs
2- ensure proper readability
3-context of use & appropriate standardization, integration, consistency, portability
evaluation:
1- time to learn
2- speed of performance
3- rate of errors by user
4- retention over time
5- subjective satisfaction
motivations:
1- life-critical systems
2- industrial/commercial
3- office/home/entertainment
4- exploratory/creative/collaborative
5- sociotechnical
Universal Usability:
1- Variations in physical abilities & physical workplaces
2- diverse cognitive & perceptual abilities
3- personality differences
4- cultural & international diversity
5- users with disabilities
6- older adult users
7- designing for/with children
8- hardware and software diversity
In discussing the usability of a computer system, it is easy to focus on the design of the interface between the user and the computer, but usability is a property of the total system. All the components must work together smoothly to create an effective and convenient digital library, for both the patrons, and for the librarians and systems administrators.
In any computer system, the user interface is built on a conceptual model that describes the manner in which the system is used.
The introduction of browsers, notably Mosaic in 1993, provided a stimulus to the quality of user interfaces for networked applications.
Mobile code gives the designer of a web site the ability to create web pages that incorporate computer programs
Interface design is partly an art, but a number of general principles have emerged from recent research. Consistency is important to users, in appearance, controls, and function. Users need feedback; they need to understand what the computer system is doing and why they see certain results. They should be able to interrupt or reverse actions. Error handling should be simple and easy to comprehend. Skilled users should be offered shortcuts, while beginners have simple, well-defined options. Above all the user should feel in control.
Research into functional design provides designers with choices about what functions belong on which of the various computers and the relationships between them.
A presentation profile is an interesting concept which has recently emerged. Managers of a digital library associate guidelines with stored information. The guidelines suggest how the objects might be presented to the user. For example, the profile might recommend two ways to render an object, offering a choice of a small file size or the full detail.
Few computer systems are completely reliable and digital libraries depend upon many subsystems scattered across the Internet
Kling and Elliott
"Systems usability" refers to how well people can exploit a computer system's intended functionality. Usability can characterize any aspect of the ways that people interact with a system, even its installation and maintenance.
wo key forms of DL usability - interface and organizational. The interface dimensions are centered around an individual's effective acclimation to a user interface, while the organizational dimensions are concerned with how computer systems can be effectively integrated into work practices of specific organizations.
interface usability dimensions:
1. Learnability - Ease of learning such that the user can quickly begin using it.
2. Efficiency - Ability of user to use the system with high level of productivity.
3. Memorability - Capability of user to easily remember how to use the system after not using it for some period.
4. Errors - System should have low error rate with few user errors and easy recovery from them. Also no catastrophic errors.
organizational usability dimensions include:
1. Accessibility - Ease with which people can locate specific computer systems, gain physical access and electronic access to their electronic corpuses. This dimension refers to both physical proximity and administrative/social restrictions on using specific systems.
2. Compatibility - Level of compatibility of file transfers from system to system.
3. Integrability into work practices - How smoothly the system fits into a person or group's work practices.
4. Social-organizational expertise - The extent to which people can obtain training and consulting to learn to use systems and can find help with problems in usage.
A great deal of people's satisfaction is influenced by the size and content of the corpus of a DL service"Design for usability" is a new term that refers to the design of computer systems so that they can be effectively integrated into the work practices of specific organizations.
The usability engineering life cycle model includes these stages proposed as a paradigm for companies to follow:
1. Know the user - Study intended users and use of the product. At a minimum, visit customer site to study user's current and desired tasks, and to understand the evolution of the user and the job.
2. Competitive analysis - Analyze existing products according to usability guidelines and perform user tests with products.
3. Setting usability goals - Establish minimal acceptable level of usability and estimate the financial impact on cost of users' time.
4. Parallel design - Use several designers to explore different design alternatives before deciding on one final design.
5. Participatory design - Include end-users throughout design phase.
6. Coordinated design of the total interface - Maintain consistency across screen layouts, documentation, on-line help systems, and tutorials.
7. Apply guidelines and heuristic analysis - Select user interface guideline appropriate for situation.
8. Prototyping - Build prototype to pretest on end-users.
9. Empirical testing - Test end-users on specific usability attributes.
10. Iterative design - Capture design rationale through iterative testing and design.
11. Collect feedback from field use - Gather usability work from field studies for future design.
The organizationally sensitive model of "design for usability" is a new model. It refers to the design of computer systems so that they can be effectively integrated into the work practices of specific organizations. It goes beyond the focus on user interfaces. "Design for usability" includes the infrastructure of computing resources which are necessary for supporting and accommodating people as they learn to maintain and use systems. "Design for usability" encourages system designers either to accommodate to end-users' mix of skills, work practices, and resources or to try to alter them
Saracevic:
Usability has been used widely in digital library evaluation, but there is no uniform definition of
what does it cover in digital library context. Usability is a very general criterion that covers a lot
of ground and includes many specific criteria – it is a meta term. ISO defines usability “as the
extent to which a product can be used by specified users to achieve specified goals with
effectiveness, efficiency and satisfaction in a specified context of use"
users have many difficulties with digital libraries, such as:
– they usually do not fully understand them
– they hold different conception of a digital library from operators or designers
– they lack familiarity with the range of capabilities, content and interactions
provided by a digital library.
– they often engage in blind alley interactions
in use, more often than not, digital library users and digital libraries are in an
adversarial position
The ultimate evaluation of digital libraries will revolve around assessing transformation of their
context – determining possible enhancing changes in institutions, learning, scholarly publishing,
disciplines, small worlds and ultimately society due to digital libraries.
Sheiderman and Plaisant
Human-Computer Interaction
Requirements analysis:
1- ascertain user needs
2- ensure proper readability
3-context of use & appropriate standardization, integration, consistency, portability
evaluation:
1- time to learn
2- speed of performance
3- rate of errors by user
4- retention over time
5- subjective satisfaction
motivations:
1- life-critical systems
2- industrial/commercial
3- office/home/entertainment
4- exploratory/creative/collaborative
5- sociotechnical
Universal Usability:
1- Variations in physical abilities & physical workplaces
2- diverse cognitive & perceptual abilities
3- personality differences
4- cultural & international diversity
5- users with disabilities
6- older adult users
7- designing for/with children
8- hardware and software diversity
Wednesday, October 22, 2008
Friday, October 17, 2008
muddiest point - week 7
no real muddiest point, just still haven't been able to install apache/greenstone
Reading Notes - Week 8
Miller - Federated Searching: Put it in it's Place
The overwhelming success of Google offers powerful evidence as to which search model users prefer.
the universe of available content is no longer limited to that stored within the library walls. Moreover, the type of content required by users is often not cataloged by most libraries.
Providing books and other cataloged material is only one aspect of the modern library's charter.
Google has taught us, quite powerfully, that the user just wants a search box. Arguments as to whether or not this is "best" for the user are moot—it doesn't matter if it's best if nobody uses
Hane - The Truth about federated searching
Federated searching is a hot topic that seems to be gaining traction in libraries everywhere
It's very difficult to manage authentication for subscription databases, particularly for remote users
It's impossible to perform a relevancy ranking that's totally relevant.
You can't get better results with a federated search engine than you can with the native database search. The same content is being searched, and a federated engine does not enhance the native database's search interface. Federated searching cannot improve on the native databases' search capabilities. It can only use them.
Lossau - Search Engine TEchnology and Digital LIbraries
Libraries see themselves as central information providers for their clientele, at universities or research institutions. But how do they define academic content?
Libraries still see themselves as a place of collections rather than as an information "gateway". Other concerns of libraries are grounded in the fact that there is no guarantee that a remote host will maintain its resources in the long-term.
paper from Michael Bergman on the "Deep Web" [2], highlights the dimensions we have to consider. Bergman talks about one billion individual documents in the "visible" [3] and nearly 550 billion documents on 200,000 web sites in the "deep" web
Libraries are increasingly hesitant to support big, monolithic and centralised portal solutions equipped with an all-inclusive search interface which would only add another link to the local, customer-oriented information services.
particularly at universities, libraries deal with a range of users with often different usage behaviours. It almost goes without saying that an undergraduate has other demands for information than a qualified researcher, and their usage behaviours can vary substantially. Young undergraduates will try much harder to transfer their general information seeking behaviour (using internet search engines) to the specific, academic environment, while established researchers have better accommodated the use of specific search tools
Current digital library systems integrate predominantly online library catalogues and databases with some full text repositories (e.g. e-journal
The continual exponential growth in the volume of online web content as described above makes it unrealistic to believe that one library can build one big, all-inclusive academic web index. Even to provide a substantial part, such as indexing the academic online content of one country, would mean a major challenge to one institution. Thus, collaboration is required among libraries
Lynch - Z39.50 Information Retrieval
Z39.50 is one of the few examples we have to date of a protocol that actually goes beyond codifying mechanism and moves into the area of standardizing shared semantic knowledge. The extent to which this should be a goal of the protocol has been an ongoing source of controversy and tension within the developer community
"Information Retrieval (Z39.50); Application Service Definition and Protocol Specification, ANSI/NISO Z39.50-1995" -- is a protocol which specifies data structures and interchange rules that allow a client machine (called an "origin" in the standard) to search databases on a server machine (called a "target" in the standard) and retrieve records that are identified as a result of such a search
Z39.50 has its roots in efforts dating back to the 1970s to allow standardized means of cross-database searching among a handful of (rather homogeneous) major bibliographic databases hosted by organizations such as the Library of Congress, the Online Computer Library Center (OCLC), and the Research Libraries Information Network
Z39.50 becomes linked to the semantics of the databases being searched in two primary areas: the attribute sets used to describe the access points being searched, and the record syntax (and related record composition control parameters in PRESENT) that are used to actually transfer records back from server to client.
OAI-PMH
designed to enable greater interoperability between digital libraries. simpler than Z39.50
works with structured data, specifically XML
document-like objects
primary purpose is to define a standard way to move metadata from point a to point b within the virtual information space of the www
OAI formed 1999
OAI-PMH 2000
formal public opening 2001 "open day"
NOT inherently open access, nor traditional ARCHIVES
The overwhelming success of Google offers powerful evidence as to which search model users prefer.
the universe of available content is no longer limited to that stored within the library walls. Moreover, the type of content required by users is often not cataloged by most libraries.
Providing books and other cataloged material is only one aspect of the modern library's charter.
Google has taught us, quite powerfully, that the user just wants a search box. Arguments as to whether or not this is "best" for the user are moot—it doesn't matter if it's best if nobody uses
Hane - The Truth about federated searching
Federated searching is a hot topic that seems to be gaining traction in libraries everywhere
It's very difficult to manage authentication for subscription databases, particularly for remote users
It's impossible to perform a relevancy ranking that's totally relevant.
You can't get better results with a federated search engine than you can with the native database search. The same content is being searched, and a federated engine does not enhance the native database's search interface. Federated searching cannot improve on the native databases' search capabilities. It can only use them.
Lossau - Search Engine TEchnology and Digital LIbraries
Libraries see themselves as central information providers for their clientele, at universities or research institutions. But how do they define academic content?
Libraries still see themselves as a place of collections rather than as an information "gateway". Other concerns of libraries are grounded in the fact that there is no guarantee that a remote host will maintain its resources in the long-term.
paper from Michael Bergman on the "Deep Web" [2], highlights the dimensions we have to consider. Bergman talks about one billion individual documents in the "visible" [3] and nearly 550 billion documents on 200,000 web sites in the "deep" web
Libraries are increasingly hesitant to support big, monolithic and centralised portal solutions equipped with an all-inclusive search interface which would only add another link to the local, customer-oriented information services.
particularly at universities, libraries deal with a range of users with often different usage behaviours. It almost goes without saying that an undergraduate has other demands for information than a qualified researcher, and their usage behaviours can vary substantially. Young undergraduates will try much harder to transfer their general information seeking behaviour (using internet search engines) to the specific, academic environment, while established researchers have better accommodated the use of specific search tools
Current digital library systems integrate predominantly online library catalogues and databases with some full text repositories (e.g. e-journal
The continual exponential growth in the volume of online web content as described above makes it unrealistic to believe that one library can build one big, all-inclusive academic web index. Even to provide a substantial part, such as indexing the academic online content of one country, would mean a major challenge to one institution. Thus, collaboration is required among libraries
Lynch - Z39.50 Information Retrieval
Z39.50 is one of the few examples we have to date of a protocol that actually goes beyond codifying mechanism and moves into the area of standardizing shared semantic knowledge. The extent to which this should be a goal of the protocol has been an ongoing source of controversy and tension within the developer community
"Information Retrieval (Z39.50); Application Service Definition and Protocol Specification, ANSI/NISO Z39.50-1995" -- is a protocol which specifies data structures and interchange rules that allow a client machine (called an "origin" in the standard) to search databases on a server machine (called a "target" in the standard) and retrieve records that are identified as a result of such a search
Z39.50 has its roots in efforts dating back to the 1970s to allow standardized means of cross-database searching among a handful of (rather homogeneous) major bibliographic databases hosted by organizations such as the Library of Congress, the Online Computer Library Center (OCLC), and the Research Libraries Information Network
Z39.50 becomes linked to the semantics of the databases being searched in two primary areas: the attribute sets used to describe the access points being searched, and the record syntax (and related record composition control parameters in PRESENT) that are used to actually transfer records back from server to client.
OAI-PMH
designed to enable greater interoperability between digital libraries. simpler than Z39.50
works with structured data, specifically XML
document-like objects
primary purpose is to define a standard way to move metadata from point a to point b within the virtual information space of the www
OAI formed 1999
OAI-PMH 2000
formal public opening 2001 "open day"
NOT inherently open access, nor traditional ARCHIVES
Friday, October 10, 2008
Reading Notes - Week 7
Henzinger et. al.
users of web search engines tend to examine only the first page of search results. for commercially-oriented web sites whose income depends on their traffic, it is in their interest to be ranked within the top 10 results for a query relevant to the content of the web site.
to achieve high rankings, authors either use a text-based approach, a link-based approach, a cloaking approach, or a combination thereof.
traditional research in information retrieval has not had to deal with this problem of malicious content in the corpora.
the web is full of noisy, low-quality, unreliable, and indeed contradictory content. In designing a high-quality search engine, one has to start with the assumption that a typical document cannot be "trusted" in isolation, rather it is the synthesis of a large number of low-quality documnets that provides the best set of results.
layout information in HTML may seem of limited utility, especially compared to information contained in languages like XML that can be used to tag content, but in fact it is a particularly valuable source of meta-data.
There are two way to try to improve ranking. one is to concentrate on a small set of keywords, and try to improve perceived relevance for that set of keywords. another technique is to try and increase the number of keywords for which the document is perceived relevant by a search engine.
a common approach is for an author to put a link farm at the bottom of every page in a site, where a link farm is a collection of links that points to every other page in that site, or indeed to any site that the author controls.
doorway pages are web pages that consist entirely of links. they are not intended to be viewed by humans; rather, they are constructed in a way that makes it very likely that search engnes will discover them.
cloaking involves serving entirely different content to a search engine crawler than to other users.
while there has been a great deal of research on determining the relevance of documents, the issue of document quality of accuracy has not been received much attention.
another promising area of research is to combine established link-analysis quality judgments with text-based judgments.
three assumed web conventions:
1) anchor text is meant to be descriptive
2) assume that if a web page author includes a link to another page, it is because the author believes that readers of the source page will find the destination page interesting and relevant.
3) META tags: currently the primary way to include metadata within HTML. content META tag used to describe the content of the document.
duplicate hosts are the single largest source of duplicate pages on the web, so solving the dupicate hosts problem can result ina significantly improved web crawler.
vaguely-structured date: information on these web pages is not structured in a database sense, typically it's much closer to prose than to data, but it does have some structure, often unintentional, exhibited through the use of HTML markup. not typically the intent of the webpage author to describe the documents semantics.
Hawking, pt. 1
search engines cannot and should not index every page on the web.
crawling proceeds by making an HTTP request to fetch the page at the first URL in the queue. when the crawler fetches the page, it scans the contents for links to other URLs and adds each previously unseesn URL to the queue.
even hundredfold parallelism is not sufficient to achieve the necessary crawling rate.
robots.txt file to determine whether the webmaster has specified that some or all of the site should not be crawled.
search engine companies use manual and automated analysis of link patterns and content to identify spam sites that are then included in a blacklist.
crawlers are highly complex parallel systems, communication with millions of different web servers, among which can be found every conceivable failure mode, all manner of deliberate and adcidental crawler traps, and every variety of noncompliance with published standards.
Hawking, pt. 2
search engines use an inverted file to rapidly identify indexing terms - the documents that contain a particular word or phrase.
in the first phase, scanning, the indexer scans the text of each input document.
in the scond phase, inversion, the indexer sorts the temporary file into term number order, with the document number as the secondary sort key.
the scale of the inversion problem for a web-sized crawl is enormous.
there is a strong economic incentive for serach engines to use caching to reduce the cost of answering queries.
Lesk, ch. 4
users of web search engines tend to examine only the first page of search results. for commercially-oriented web sites whose income depends on their traffic, it is in their interest to be ranked within the top 10 results for a query relevant to the content of the web site.
to achieve high rankings, authors either use a text-based approach, a link-based approach, a cloaking approach, or a combination thereof.
traditional research in information retrieval has not had to deal with this problem of malicious content in the corpora.
the web is full of noisy, low-quality, unreliable, and indeed contradictory content. In designing a high-quality search engine, one has to start with the assumption that a typical document cannot be "trusted" in isolation, rather it is the synthesis of a large number of low-quality documnets that provides the best set of results.
layout information in HTML may seem of limited utility, especially compared to information contained in languages like XML that can be used to tag content, but in fact it is a particularly valuable source of meta-data.
There are two way to try to improve ranking. one is to concentrate on a small set of keywords, and try to improve perceived relevance for that set of keywords. another technique is to try and increase the number of keywords for which the document is perceived relevant by a search engine.
a common approach is for an author to put a link farm at the bottom of every page in a site, where a link farm is a collection of links that points to every other page in that site, or indeed to any site that the author controls.
doorway pages are web pages that consist entirely of links. they are not intended to be viewed by humans; rather, they are constructed in a way that makes it very likely that search engnes will discover them.
cloaking involves serving entirely different content to a search engine crawler than to other users.
while there has been a great deal of research on determining the relevance of documents, the issue of document quality of accuracy has not been received much attention.
another promising area of research is to combine established link-analysis quality judgments with text-based judgments.
three assumed web conventions:
1) anchor text is meant to be descriptive
2) assume that if a web page author includes a link to another page, it is because the author believes that readers of the source page will find the destination page interesting and relevant.
3) META tags: currently the primary way to include metadata within HTML. content META tag used to describe the content of the document.
duplicate hosts are the single largest source of duplicate pages on the web, so solving the dupicate hosts problem can result ina significantly improved web crawler.
vaguely-structured date: information on these web pages is not structured in a database sense, typically it's much closer to prose than to data, but it does have some structure, often unintentional, exhibited through the use of HTML markup. not typically the intent of the webpage author to describe the documents semantics.
Hawking, pt. 1
search engines cannot and should not index every page on the web.
crawling proceeds by making an HTTP request to fetch the page at the first URL in the queue. when the crawler fetches the page, it scans the contents for links to other URLs and adds each previously unseesn URL to the queue.
even hundredfold parallelism is not sufficient to achieve the necessary crawling rate.
robots.txt file to determine whether the webmaster has specified that some or all of the site should not be crawled.
search engine companies use manual and automated analysis of link patterns and content to identify spam sites that are then included in a blacklist.
crawlers are highly complex parallel systems, communication with millions of different web servers, among which can be found every conceivable failure mode, all manner of deliberate and adcidental crawler traps, and every variety of noncompliance with published standards.
Hawking, pt. 2
search engines use an inverted file to rapidly identify indexing terms - the documents that contain a particular word or phrase.
in the first phase, scanning, the indexer scans the text of each input document.
in the scond phase, inversion, the indexer sorts the temporary file into term number order, with the document number as the secondary sort key.
the scale of the inversion problem for a web-sized crawl is enormous.
there is a strong economic incentive for serach engines to use caching to reduce the cost of answering queries.
Lesk, ch. 4
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