1. The Graph Structure of RDF Sentences
瞿裕忠（Yuzhong Qu）
计算机科学与技术系

2. 引言
An empirical study on the graph structure of RDF Sentences in the Web of Data
The structural nature of RDF sentences in the Linked Data

3. Terminology
RDF sentence, G

4. Terminology Statistics
Cumulative distribution of RDF sentences over RDF docs
包含  k 个RDF句子的文档 （百分数）
Cumulative distribution of non-trivial RDF sentences over RDF docs
包含  k 个非平凡RDF句子的文档 （百分数）
Black nodes over（non-trivial）RDF sentences
包含  k 个black nodes 的（非平凡）句子 （百分数）
RDF triples over non-trivial RDF sentences
包含  k 个triples的非平凡句子 （百分数）

5. Terminology
A digraph is called "simple" if it has no loops, and no multiple arcs (arcs with same starting and ending nodes)
A directed graph is an oriented simple graph if and only if it has neither self-loops nor 2-cycles.
Simple, oriented simple
Self-loop?
Multiple arcs?
Cycles of length 2?

6. Terminology Skeleton subgraph, GS Black node subgraph, GB
removing literal nodes
Black node subgraph, GB
induced subgraph by black nodes

7. Terminology
A digraph is called "simple" if it has no loops, and no multiple arcs (arcs with same starting and ending nodes)
A directed graph is an oriented simple graph if and only if it has neither self-loops nor 2-cycles.
Self-loop in GB
Multiple arcs in GB/GS/G?
Cycles of length 2 in GB/GS?

8. Terminology Start point: all other vertices are reachable from it
Start points in G = Start points in GS
? # start points in GS
? # start points in GB

9. Terminology U(GS): Underlying graph of GS
U(GB): Underlying graph of GB
Linear, Tree, Graph with cycles

10. Q&A