User:Tim Lebo
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Contents |
Advanced Semantic Web (Fall 2008)
Overview of participation
Of the 42 paper presentations, Tim Lebo presented 3, attended 25, and did not attend 3.
While attending CSCI 6966 Advanced Semantic Web (Fall 2008), Tim Lebo gave four presentations:
- a summary of his current "Accountable Visualization" research,
- an overview of two conference papers, and
- an overview of one journal article.
Tim Lebo made 47 posts containing comments and questions regarding presented papers. Many of these posts pose multiple questions.
Tim Lebo also contributed to the organization of the course wiki. The Course wiki contributions section lists these contributions.
Presentation attendance
| Presentations Tim Lebo did not attend | Speaker | Date |
|---|---|---|
| Ankesh Sep11 | Ankesh Khandelwal | 245472111 September 2008 |
| NSPARQL Jesse Weaver 20080911 | Jesse Weaver | 245472111 September 2008 |
| Debbie Rank Typed Graph Walks Presentation | Debbie Heisler | 245476323 October 2008 |
Tim left early on 11 September for a business trip and was at VisWeek for the week of 23 October.
Papers presented
Tim Lebo gave the following paper presentations for this course:
| Presentation Page | Title of paper | Paper has author |
|---|---|---|
| Abel2007enabling presented by Tim Lebo 25 sept 2008 | Enabling Advanced and Context-Dependent Access Control in RDF Stores | Fabian Abel Juri Luca De Coi Nicola Henze Arne Wolf Koesling Daniel Krause Daniel Olmedilla |
| Theoharis2008graph presented by Tim Lebo 4 dec 2008 | On Graph Features of Semantic Web Schemas | Yannis Theoharis Yannis Tzitzikas Dimitris Kotzinos Vassilis Christophides |
| Zhao2004using presented by Tim Lebo 9 oct 2008 | Using Semantic Web Technologies for Representing E-science Provenance | Jun Zhao Chris Wroe Carole A. Goble Robert Stevens Dennis Quan Mark Greenwood |
Questions posed
Tim Lebo posted the following in preparation for attending paper presentations for this course:
| About | Text |
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| Anyanwu2005semrank | The authors propose a few interesting metrics for ranking a set of semantic paths. A semantic path is an instance of a Semantic Association, which is a sequence of (RDF) properties. In the Background/Motivation section, the authors illustrate and define three example Property Sequences: rho-pathAssociation, rho-joinAssociation, and rho-isoAssociation.
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| Anyanwu2005semrank | The information content I(ps) is the addition of three terms: a ROC-aware min, a ROC-aware avg, and a non-ROC-aware max. The refraction count RC(PS) relies on the Semantic Summary, which in turn relies on the ROCs. The S-Match(property,keyword) metric relies on a property hierarchy. The final SEMRANK metric involves a (modulated) composition of five terms, four of which rely on a schema to be defined.
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| Carroll2005named | When comparing TriX to RDF/XML, the authors state, "The URI at which an RDF/XML document is published is used for three different purposes: as a retrieval address, with an operational semantics; as a means of identifying the document; and as a means of identifying the graph described by the document. There is potential for confusion between these three uses." The URIRef for a named graph performs only the latter function (identifying the graph).
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| Cattuto2008semantic | |
| Cattuto2008semantic | The introduction motivates the investigation of relatedness measures: "We believe that a deeper insight into the semantic properties of relatedness measures is an important prerequisite for the design of ontology learning procedures..." Although relatedness measures may be necessary for a "Ontology Learning" capability, they are arguably insufficient on their own.
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| Cattuto2008semantic | The paper compares five relatedness metrics. We could sit down and make up ten more.
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| Cattuto2008semantic |
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| Cattuto2008semantic | Notation nit: <math>R^T</math> and <math>R^n</math> seem to be used synonymously -- what is the distinction? Shouldn't <math>R^T</math> be <math>R^ |
| Cattuto2008semantic | I don't understand the statement "The reason for giving weight zero between a node and itself is that we want two tags to be considered related when they occur in a similar context, and not when they occur together.
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| Cattuto2008semantic | The description of FolkRank mentions "random surfer vector" but does not introduce the term or it's purpose.
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| Eiter2008combining | The paper describes a "conservative extension" to the combination of DL's first-order semantics and logic programming's answer set semantics, where knowledge can be transferred between a DL knowledge base and a logic programming program. When describing how dl-programs can express the closed-world assumption "on top" of an external DL knowledge base, negation is asserted despite its DL provability.
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| Fokoue2006summary | The summary of an Abox takes advantage of redundant assertions w.r.t consistency checking by collapsing individuals that are members of the same concept sets and are /not/ explicitly asserted to be different from each other. The authors note, "Any explicit assertions that two individuals are different from each other are maintained in the summary Abox."
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| Gil2007towards | The results of the simulation compare the Mean Squared Error, k-sum, and Edit Distance to a 'baseline', which is "a ... search engine ... that ranks search results by topic and popularity, ... without taking trust into account." A lot of assumptions are made to model the trust users have for associations and resources, and the simulation used 1,000 queries generated from 1,000 generated resources, 10,000 generated associations, and 1,000 generated users.
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| Grau2007history | The authors open the abstract by stating, "The development of ontologies involves continuous but relatively small modifications." A reasonable first step to reduce the ontology development cycle is to tackle the problem addressed in the paper: classify ontology O^2 by reusing the "evidences" from the classification of O^1, the set of added axioms, and the set of removed axioms. Their "module" technique can then be applied at each committed change. This addresses the relatively small modifications aspect of ontology development,
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| Gutierrez2007introducing |
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| Gutierrez2007introducing | According to Footnote 3, the authors "chose not to ((use the standard reification vocabulary of RDF)) to stress the fact that the notions presented in this paper are independent of any view one may have about the concept of reification in RDF." Yet the "temporal label" is constructed in the exact same way the standard reification vocabulary would do it (:tsubj rdfs:subPropertyOf rdf:subject . :tpred rdfs:subPropertyOf rdf:predicate . :tobj rdfs:subPropertyOf rdf:object.).
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In Definition 3, a mapping m is a 5-tuple <id,u,v,t,f>, where u is an element of the relational schema, v is an element of the ontology, t is a relationship (e.g., equivalence or subsumption), and f is a confidence measure. Phase II of the matching process views each element of the relational schema and ontology as a "virtual document" that is compared to the other elements' "virtual documents" using the the TF/IDF cosine measure. In a mapping m, id, u, v, and f are providing in this process.
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| Janik2005brahms |
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| Janik2005brahms |
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| Lin2008discovering | The authors make a very good point regarding the "ill defined" nature of using probabilistic measures for a deterministic graph structure. The two Random Experiments that they propose are unique, intuitive, and probabilistically sound methods for obtaining probabilistic measures. But from the time that they propose the method, they do not discuss the methods' computational expense until the last paragraph of the paper, "an important future direction is to improve the scalability of the system. What is most expensive is the computation of feature values, since it requires the system to count a potentially large number of paths."
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| Moreau2007open | It is clear that the intent of this paper is to introduce the start of a common model for provenance and NOT to motivate the use of provenance systems. The need for a common model for any mutual interest is self-evident. However, some motivation for the use of provenance would be helpful.
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| Noy2008collecting | The ability to provide a "One-stop shopping for ontology resources" remains overdue.
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| Noy2008collecting |
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| Noy2008collecting | The authors state "One mapping can depend on another: 'If X is Y, then A is B'."
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| Noy2008collecting | (diagram nit) Fig. 2 is great for illustrating the connectivity between ontologies. Making the nodes' size proportional to the size of the ontologies they represent might be more communicative, since the cardinality between two ontologies could usefully be considered with respect to the sizes of each ontology. |
| Noy2008collecting | Claims of "complete domain-independence" are often overstatements.
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| Perez2008nsparql | The "path-like" nature resembles Fresnel Selector Language (FSL) http://www.w3.org/2005/04/fresnel-info/fsl/.
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| Perez2008nsparql | (just a comment) The "axis-like" nature, along with the "forward-backward" directionality, resembles Ted Nelson's zzStructure http://www.nongnu.org/gzz/gi/gi.html. The zzStructure incorporates a layout that facilitates visual navigation. It would be interesting to compare this work from a different discipline in a different era (he was decades ago). |
| Perez2008nsparql | The authors note "the occurrence of variables in the predicate position of triple patterns is forbidden in nSPARQL." This limitation resembles another that was described in the DARQ paper: "The matching compares the predicate in a triple pattern with the predicate defined for a capability and evaluated the constraint for subject and object. Because matching is based on predicates, DARQ currently only supports queries with bound predicates."
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| Perez2008nsparql |
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| Quilitz2008querying | The authors state, "There is no other need for cooperation except of the support of the SPARQL protocol." Yet later, "To find the relevant information sources for the different triples in a query and to decompose the query into sub-queries the query engine needs information about the data sources." DARQ relies on the service descriptions to determine how to decompose the query.
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| Quilitz2008querying |
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| Quilitz2008querying |
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| Quilitz2008querying |
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| Quilitz2008querying | It is not clear how the dbpedia data were split across the two servers.
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| Quilitz2008querying |
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| Quilitz2008querying |
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| Rahwan2007laying | The authors chose to model their argument ontology in RDFS.
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| Schenk2008networked | The extension of named graphs that the authors describe looks like it will be very useful in Semantic Web applications. A couple of pragmatic questions.
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| Schenk2008networked | In the Related Work section, the authors compare Networked Graphs to ActiveXML: "The semantics of ActiveXML documents is also defined using a fixpoint, but unlike NGs, ActiveXML documents are infinite in general."
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| Schenk2008networked | In the Related Work section, the authors compare Networked Graphs to NRL: "NEPOMUK Representation Language NRL ... allows for various ways to specify 'views', which are defined with a procedural semantics in contrast to the declarative semantics of NGs."
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| Schmidt2008experimental | The only place the ratios of usr, sys, and total response times are mentioned is in the discussion for Q1 ("Return the year of publication of 'Journal 1 (1940)'", where the authors state, "The gap between total and usr+sys for 25M indicates that much time is spent in waiting for data being read from or written to disk". The choice to use different vertical scales in Figures 1-3 leads to an investigation of these ratios while obscuring a natural consideration of the more important issue: the relative response times between triple store approaches. Regardless, the ratio usr/sys falls within one of three categories: minority/majority, all/none, and none/none -- and the ratio's category transitions from none/none, to all/none, to minority/majority as the data size increases within a condition.
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| Schueler2008querying | When describing their design choices, the authors state, "For compliance with existing applications that access the repository in a common way (e.g. using SPARQL queries), we do not modify existing user data." The preservation of user data is clearly a important. But they disregard RDF reification as an option, saying "This requirement does not allow us to use mechanisms like RDF reification, which decompose existing triples and fully change the representation model."
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| Schwitter2008controlled | The Controlled Natural Language presented in this paper seems to be useful for pedagogical purposes, but little more. Although hiding a more obscure syntax /may/ increase the approachability and/or "explainability", it seems that a novice would still require a background understanding of OWL Lite^minus to do anything useful. The novice is at risk for establishing a greater expectation for the language based on the assumption that the English-like sentences are English; these expectations will be unfulfilled by the restricted ("focused"?) capabilities of a logic-based system. On the other hand, the verbosity that provides approachability for the novice would hinder use by "knowledge engineers" who prefer a more concise syntax. However, these issues are most concerning only when authoring the TBox and ABox. When posing questions to the system, the interaction seems more natural. This is done by generating a satisfying model with SATCHMO, which includes all entailed statements.
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| Szomszor2008semantic | The authors claim that "Tagging ... (is a) knowledge management mechanism that users find easy to use and understand."
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| Szomszor2008semantic | The authors claim that their "results show that far richer interest profiles can be generated."
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| Udrea2007grin | It would seem that the method used to determine cluster centers would drastically influence query performance. The selected clustering algorithm (e.g., PAM) and the inter-cluster metric (e.g., single, complete, or average link) would both be factors of performance. The authors do not commit to an inter-cluster distance metric d_c and devote one sentence discussing the results of the comparison: They all "performed" the same within 5%.
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Course wiki contributions
- Created the Template:CSCI 6966 Advanced Semantic Web (Fall 2008) - Lesson index template to provide overview and navigational capabilities.
- Contributed to the wording, selected attributes, and ordering of CSCI 6966 Advanced Semantic Web (Fall 2008) All Presentations.
- Created the CSCI 6966 Advanced Semantic Web (Fall 2008) announcements page.
- Moved syllabus section to CSCI 6966 Advanced Semantic Web (Fall 2008) syllabus
- Illustrated how we could use the wiki to explain/describe the topics that we discuss (see Named graph and Reification). This is especially useful when we discuss multiple papers that discuss similar notions (see s).
Other
He also likes ice cream, and cookies, and ate chocolate at least one time in his life.
[ p:s Tim Lebo; p:p ate; p:o chocolate; date "2008/12/3"; ] .
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