Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Geog 119 LE 2 > Module 3 > Flashcards

Module 3 Flashcards

1
Q

} system of roads, streets, pipes, aqueducts, power lines, or nearly any structure which
permits either vehicular movement or flow of some commodity
} figure made up of points (vertices) connected by non-intersecting curves (arcs)
} Model-based definition of ____

A

Networks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

} simplified version of a slice of reality
} Pattern, plan, representation (especially in miniature), or description designed to show
the main object or workings of an object, system, or concept
} Building blocks of theories, foundations of a science

A

Model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Importance of Models:

A

} Possible to deliberately eliminate real world complexities
} Enabling greater comprehension
} Enable abstraction
} Possible to manipulate data and test relationships among the components of the
problem
} Allow generalizations
} Constitute a common language of scientific discourse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Types of Models:

A

Iconic Models
Analog Models
Symbolic Models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

} all the properties and relationships of the original phenomenon are represented at a
reduced scale
} Examples : Model trains; Aerial photographs

A

Iconic Models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

} only those characteristics of the real world considered to be significant are
incorporated.
} Certain level of abstraction
§ (from the Latin abs, meaning away from and trahere, meaning to draw)
§ certain things are eliminated, others are shown in stylized manner
§ analogy is drawn between phenomena in apparently disparate fields
} Example: Topographic Map; Globe

A

Analog Models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

} relationships are expressed usually by mathematical symbols in equation form
} Example: E=mc2

A

Symbolic Models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

} set of systematically organized points and lines
} a collection of vertices or nodes and a collection of edges that connect pairs of
vertices
} a set of vertex (nodes) v connected by edges (links) e. Thus G=(v , e).

A

Graphs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Major properties of ordinary graphs:

A

} A network has a finite number of places
} Each route is a set consisting of two places
} Each route joins two different places
} At the most, only one route may join a pair of places
} No distinctions are made between the initial and the terminal places or
routes
} Routes are two-way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The origins of graph theory can be traced to ____ who devised in 1735
a problem that came to be known as the “_____”.

A

Leonhard Euler, Seven Bridges of Konigsberg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

} branch of combinatorial topology
} Allows us to disentangle the basic structure of transportation

A

Graph Theory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A ____ is a terminal point or an intersection point of a graph. It is the
abstraction of a location such as a city, an administrative division, a road intersection or a
transport terminal (stations, terminuses, harbors and airports).

A

Vertex (Node)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

An ___ is a link between two nodes. The link (i , j) is of initial
extremity i and of terminal extremity j. A link is the abstraction of a transport infrastructure
supporting movements between nodes. It has a direction that is commonly represented as
an arrow. When an arrow is not used, it is assumed the link is bi-directional.

A

Edge (Link)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

A ___ is a subset of a graph G where p is the number of ___. For instance G’ = (v’, e’) can be a distinct ___ of G. Unless the global transport system is considered in its whole, every transport network is in theory a ___ of
another. For instance, the road transportation network of a city is a ___ of a regional
transportation network, which is itself a ___ of a national transportation network.

A

Sub-Graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A link that makes a node correspond to itself is a ___.

A

Buckle (Loop or Self-Edge)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A graph that includes only
one type of link between its nodes. A road
or rail network are ____?

A

Simple Graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A graph that includes several
types of links between its nodes. Some
nodes can be connected to one link type
while others can be connected to more than
one that are running in parallel. A graph
depicting a road and a rail network with
different links between nodes serviced by
either or both modes is a ____?.

A

Multigraph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

____ have nodes connected by only one link type, such as road or rail links. A ___ can contain more than one link type between the same two nodes (a combination of two ____ graphs).

A

Simple Graph, Multigraph, Simple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A ____ enables flows of people, freight or information, which are
occurring along its links.

A

Transportation Network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Graph theory must thus offer the possibility of representing
movements as linkages, which can be considered over several aspects:

A

Connection
Path
Chain
Length of a Link, Connection, or Path
Cycle
Circuit
Clique
Cluster
Ego Network
Nodal Region
Dual Graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A set of two nodes as
every node is linked to the other. Considers
if a movement between two nodes is
possible, whatever its direction. Knowing
connections makes it possible to find if it is
possible to reach a node from another node
within a graph.

A

Connection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

A sequence of links that are
traveled in the same direction. For a ____ to
exist between two nodes, it must be
possible to travel an uninterrupted
sequence of links. Finding all the possible
paths in a graph is a fundamental attribute
in measuring accessibility and traffic flows.

A

Path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A sequence of links having a connection in common with the other. Direction
does not matter.

A

Chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Refers to the label associated with a
link, a connection or a path. This label can be distance, the amount of traffic, the capacity or
any relevant attribute of that link. The ? of a path is the number of links (or
connections) in this path.

A

Length of a Link, Connection, or Path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Refers to a chain where the initial and terminal node is the same and that does
not use the same link more than once is a ___.

A

Cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

A path where the initial and terminal node corresponds. It is a cycle where all
the links are traveled in the same direction. ____ are very important in transportation
because several distribution systems are using ____ to cover as much territory as possible
in one direction (delivery route).

A

Circuits

27
Q

A maximal complete subgraph where all vertices are connected

A

Clique

28
Q

Also called ____, it refers to a group of nodes having denser
relationships with each other than with the
rest of the network. A wide range of methods
are used to reveal ____ in a network,
notably they are based on modularity
measures (intra- versus inter-cluster variance).

A

Cluster, Community, Clusters

29
Q

For a given node, the
____ corresponds to a sub-graph
where only its adjacent neighbors and their
mutual links are included.

A

Ego Network

30
Q

Refers to a subgroup (tree) of nodes polarized by an
independent node (which largest flow link connects a smaller node) and a number of
subordinate nodes (which largest flow link connects a larger node). Single or multiple
linkage analysis methods are used to reveal such regions by removing secondary links
between nodes while keeping only the heaviest links.

A

Nodal Region

31
Q

A method in space syntax that considers edges as nodes and nodes as
edges. In urban street networks, large avenues made of several segments become single
nodes while intersections with other avenues or streets become links (edges). This method
is particularly useful to reveal hierarchical structures in a planar network.

A

Dual Graph

32
Q

} Entails a certain amount of abstraction,
simplification and generalization
} Not scaled, spatial sequence is
maintained
} Focus is on the connections between
places
} Island boundary was eliminated
} Forks in the road network where
settlement nodes do not exist have
been eliminated
} Information loss acceptable
} Graph eliminates the flesh and blood
but retains the skeleton of the network
} Links join specific places
} Definite arrangement

A

Martinique Network

33
Q

By reducing the complex transportation network to its fundamental elements of
nodes and links, it is possible to evaluate alternative structures; this can be done
using ____.

A

Graph Theory

34
Q

This is the intersection of 2 edges which is always a vertex such as an Interstate Highway System. However, it is not always the
case in ____ graph such as an Airline Network.

A

Planar, Non-Planar

35
Q

Distance between vertices is measured by counting the
number of ___ separating them

A

Edges

36
Q

} degree of connection between all nodes in a system
} Measure of the robustness of the network
} Index of the relative simplicity or complexity of the network

A

Connectivity

37
Q

Two kinds of Connectivity:

A

§ Connectivity relating to individual vertices
§ Connectivity relating to the fineness and coarseness of the network as a whole

38
Q

k = max dij
} maximum number of distances from vertex I to each of the other vertices
} ____ – number of intervening edges between two vertices, measured along the
shortest path, regardless of the actual mileage involved

A

Konig Index, Distance

39
Q

} Topological distance from a vertex to all others in the network
} Based on the presence or absence of actual links
} Most accessible place
} can be reached with the shortest total topological distance than from any other
nodes
} does not follow that the geometric center of a region is the most accessible node

A

Accessibility Index

40
Q

} Measure the number of ways in which the ith node in a network can be reached
from the jth node in a number of steps, assuming there is no direct connections
between i and j
subjourneys, connecting flights
» (Japan Airlines ) MLA – NRT – LAX (2 steps)
»(Hawaiian Airlines ) MLA – HNL – LAX (2 steps)
»(Continental Airlines) MLA – GUM – HNL – LAX (3 steps)

A

Multi-Step Connections

41
Q

Evaluating Vertex Connectivity:

A

} Connections are reciprocal
} Some are better connected than others
} Presence of intermediaries
} Just as not all places are connected directly, so are individuals
} Necessary to go through intermediaries
} Connectivity matrix becomes useful to understand connections
} Graph theoretic measures are useful in understanding not only accessibility but the connectivity of networks
} Measures that have higher degree of utility in understanding transportation
networks

42
Q

e/v
} Number of linkages per place or nodes
} Linkage intensity
} Values of >1 suggests ___ routings
} BI is high in developed countries, low in underdeveloped regions
} Index value increases as alternative routings are constructed

A

Beta Index, Alternative

43
Q

e/(3(v-2))
} Ratio between the actual maximum possible number of edges in a graph
} Planar graph; Non Planar Graph: [2e] / [v(v-1)]
} Direct correlation with levels of economic development
} Well connected networks are characterized with the presence of loops

A

Gamma Index

44
Q

} g – ____
} disjointed entities
} evaluating network connectivity by counting loops
} almost always __?

A

Cyclomatic Number, Subgraph, 1

45
Q

} –α= e –v + g or α= _μ_2v –5 2v –5
} Measuring ratio between the actual number of loops in a graph and the maximum
possible number
} Range: 0 – 1 for both planar and non-planar graphs

A

Alpha Index

46
Q

v n
–D(G) = Σ Σ dij
i= 1 j = 1
} Measures total distances between all vertices along the shortest paths
} Evaluates the compactness of a network
} Function of the spatial arrangement of vertices with reference to the network
} i= 1 j = 1
} Measures total distances between all vertices along the shortest paths
} Evaluates the compactness of a network
} Function of the spatial arrangement of vertices with reference to the network
} The value of the S.I. Is ___ related to the degree of compactness of a
network

A

Dispersion or Shimbel Index (S.I.), Inversely

47
Q

Network Connectivity Summary
} Number of linkages per place or nodes
} Ratio between the actual and the maximum possible number of
edges in a graph
} Evaluating network connectivity by counting loops
} Measures ratio between the actual number of loops in a graph and
the maximum possible number
} Measures total distances between all vertices
along the shortest paths

A

} Beta Index
} Gamma Index
} Cyclomatic Number
} Alpha Index
} Dispersion/Shimbel Index

48
Q

Higher value,
less connected (more
peripheral (e.g. Optimal location for a train
station)

A

Konig Index

49
Q

Low value, more
connected (e.g. More places can be reached
directly from particular node)

A

Accessibility Index

50
Q

Higher value, higher
number of linkages
per node (e.g. Developed countries have
high values of ____.
Alternative links may exist.)

A

Beta Index

51
Q

Higher value, higher
accessibility between
nodes (e.g. Richer countries have higher
values due redundant links)

A

Gamma Index

52
Q

Higher value, higher
connectivity of
network (e.g. Richer countries have higher
values due redundant links.)

A

Alpha Index

53
Q

Higher value, more
connected network (e.g. Subgraphs may indicate
early economic development stage

A

Cyclomatic Number

54
Q

Transport networks are functional (why and how?):

A

o Related to physical & socioeconomic context of a nation
o Relatively advanced countries have higher index values than less developed
ones
o Technological innovation would help explain the reasons behind the index
values

55
Q

Network Regionalization:
}
}
}

A

} Certain pair of nodes are better connected than others
} Nodes relatively close to one another may tend to be highly connected
} Networks have hierarchical structure

56
Q

Nodes are linked in a variety of ways

A

Alternative Network Configuration

57
Q

Essential properties common to all hierarchies:

A

} Existence of two or more levels
} Pyramidal structure
} Number of objects at any one level decreases as we go up the hierarchy

58
Q

Nodal and Route Hierarchies Benefits:
}
}
}

A

} Advantage of considering a network as a graph
} Reduce it to its fundamental properties as nodes and links
} All are of unit size and unit length

59
Q

*Smaller towns are ___ distances apart
*As the size of the settlement increases, the average spacing between settlements of the
same size also ____

A

Lesser, Increases

60
Q

*Two prime determinants of the volume of spatial interaction:
*
*

A
  • Size of nodes
  • the distance between an origin & destination
61
Q

} Appropriate measure is the number of miles of different classes of routes
} ____ evaluated according to their capacity to accommodate traffic
} Large proportion of the total mileage consists of low-order, single track links of
relatively short lengths
} Relationships are not haphazard or random but occur in a patterned way which suggests
functional order and spatial organization
} ____ between transportation networks and drainage system

A

Route Hierarchies, Route Sizes, Isomorphism

62
Q

____ as independent variable contributing to variations in number, length, flow, and
area.

A

Path Order

63
Q

Correspondence of Nodal and Route Hierarchies:
} Large nodes, ___ order routes
} ___that are fortuitously located are also connected by these routes
} Smaller routes connect large nodes with ____
} In the real world, ____ are likely to be upgraded and low order nodes will also be served by ____

A

} High Order
} Smaller Nodes
} Smaller Nodes
} Lower-order Routes, Higher order Links

Geog 119 LE 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions