=Paper= {{Paper |id=Vol-2000/paos2017_paper1 |storemode=property |title=Action Planning based on Open Knowledge Graphs and LOD |pdfUrl=https://ceur-ws.org/Vol-2000/paos2017_paper1.pdf |volume=Vol-2000 |authors=Seiji Koide,Fumihiro Kato,Hideaki Takeda,Yuta Ochiai,Kenki Ueda |dblpUrl=https://dblp.org/rec/conf/jist/KoideK0OU17 }} ==Action Planning based on Open Knowledge Graphs and LOD== https://ceur-ws.org/Vol-2000/paos2017_paper1.pdf
      Action Planning based on Open Knowledge
                  Graphs and LOD

       Seiji Koide1 , Fumihiro Kato1 , Hideaki Takeda12 , Yuta Ochiai3 , and
                                  Kenki Ueda3
1
    National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430,
                                          Japan,
                                   takeda@nii.ac.jp,
        WWW home page: http://www-kasm.nii.ac.jp/~takeda/index.html
            2
              SOKENDAI (The Graduate University for Advanced Studies)
                               3
                                 Toyota Motor Corporation



        Abstract. In this preliminary report, we show how action planning is
        realized by using LOD datasets, e.g., Linked Geo Data, DBpedia, Word-
        Net, etc. To make a recommendation for car drivers and passengers, we
        combine these existing open datasets with newly constructed ontologies
        of facilities and services. We develop the inference procedure to translate
        user requests into SPARQL queries to obtain a recommendation on ap-
        propriate facilities for users. Common sense knowledge is also required
        in the reasoning process.

        Keywords: DBpedia, LinkedGeoData, Knowledge-based system


1     Introduction
While Linked Data is now gradually growing to be the infrastructure of coming
Knowledge Society, we are still struggling to show the potential of Linked Data
to most people in the society including basic industries. To cope with this sit-
uation and propel the deployment of Semantic Web technology, it is needed to
demonstrate the performance of linking distinct datasets and show the usefulness
of outbound and inbound linking data beyond enterprise data in diverse applica-
tions. Yet there is no linking data among large linked datasets such as DBpedia,
Freebase, and OpenCyc from the viewpoint of LOD applications, although each
collection of them are a kind of isolated showcase of LOD with internally linked
data within their own territories and objectives.
    In our use-case, the system accepts ambiguous requests from car drivers and
passengers, plans driver actions to achieve goals that satisfies the requests, in-
cluding alternatives, and makes a recommendation for the drivers and passen-
gers.
    In this preliminary work, we have found that it is required more goal-oriented
linked datasets and common sense knowledge as bridge between isolated LOD
datasets existing. We have also found that Semantic Web technology or specif-
ically RDF stores and SPARQL engines are enough as enabling technology to
create and demonstrate new applications based on heterogeneous and diverse
datasets.
    To obtain driving destinations as goal, we arranged Linked Geo Data and
DBpedia Japanese[1] with newly constructed facility ontology and service ontol-
ogy, which make links among such existing datasets. Japanese WordNet[2] is also
utilized as general knowledge, because it was necessary to make the inference
with common sense to discover destinations from user requests. We developed
the inference procedure to translate user requests into SPARQL queries to obtain
a recommendation on appropriate facilities for users.
    The purpose of this preliminary report is to make a clear direction for devel-
opment of LOD applications in order to deploy linked data as the infrastructure
of society in future. The structure of this preliminary paper is as follows. We
describe the detail of the use-case in Section 2. Section 3 reports the related work
from the viewpoint of the long-term research activity on artificial intelligence.
In Section 4, we show how we realize new ontologies on facilities and services
in order to utilize open knowledge-bases and LOD. Section 5 describes the sys-
tematization of multiple linked datasets and the SPARQL endpoint. Section 6
describes the inference procedure for the purpose of getting recommendations
by using SPARQL queries. We show how we can realize action planning by using
open knowledge-bases and LOD. Section 7 reports a simple example of execution
by this prototype system that realizes a new purpose-oriented inference engine
with SPARQL and large-scale open knowledge-bases. Section 8 provides discus-
sions. In the last section, we summarize the results and address the future work
toward the new era of Knowledge Society based on Open Data and Linked Data.


2    Problem Setting for the Use Case
In setting of the use-case, we firstly made more than ten scenarios of conversation
between users and this system. In each case, a user in a car speaks a single or
a number of requests to do something with driving a car. Then, the system
analyzes the requests under the consideration of current contexts such as time,
location, driving time, etc. At last, the system makes concrete action proposals
to visit specific points (shop, facility, etc.) or areas (sightseeing area, good place
for time-consuming, etc.) with a reasonable visiting order. Basically, the request
may be vague and complex, but the recommendation is specific and concrete.
However, every recommendation is a sequence of actions, and proposed actions
are quite limited within these scenarios, for example, drive somewhere, buy or
eat something, do some sport, and so on. One of the simplest scenarios is as
follows.
    Child passenger(hereafter C): I want to see a lion.
    System(hereafter S): How about Ueno Zoo. A baby lion was born re-
    cently.
    C: It sounds good, but I was there last month.
    S: Well, how about Kinoshita Circus. You can see a lion show there.
    C: OK. That’s fine.
    In this scenario, the system must discover the knowledge that a lion is a
kind of animal and a zoo is a public entertainment facility for seeing animals.
The system must find out a nearest zoo, that is Ueno Zoo in this case, from
the current location, and must reason that users have enough time to drive to
the destination and walking around the zoo. Furthermore, due to the negative
response of the user, the system must discover a neighboring circus that presents
a lion show as an alternative.


3   Related Work

Planning was one of the most popular AI research area in the 1970s through the
1980s, where the research efforts focused on reasoning mechanisms on making
plans [3][4][5], but the role of knowledge in inference was not regarded. Around
the 1980s, the reasoning with knowledge was well studied in problem solving,
and the efforts how to use human experts’ knowledge with inference engines
amounted to expert systems. Even after that, we have no remarkable innovation
to solve information-rich planning problems, as expert systems was confronted
with. Note that scheduling problems in project management, production man-
agement, and delivery management are rare successes by domain specific knowl-
edge and algorithms.
    The recent success of IBM Watson in TV show Jeopardy! seems to promise
knowledge graph approach for problem solving and decision making[6]. How-
ever, we should note that Watson system for Jeopardy! did not use common
sense for combining multiple knowledge graphs. Basically, the system model for
Jeopardy! game is categorized into a Q&A system for trivial knowledge. Multi-
ple knowledge graphs and selection of the most probable answer candidates are
key technique in Watson for Jeopardy!, and common sense knowledge is used
only in WATSONPATHS for breaking down the top level question into subques-
tions based on unstructured text corpus, and not used as bridge for multiple
knowledge graphs [7].
    To endow computers with common sense is one of the major long-term goals
of artificial intelligence. Common sense reasoning widely ranges over a number
of different fields from taxonomic reasoning, geographic reasoning, temporal rea-
soning, reasoning about actions and changes, qualitative reasoning [8] to naive
physics, interpersonal interaction theory, and social relationship theory. Mueller
[7] described common sense reasoning based on event calculus. The knowledge-
based approach of common sense reasoning is categorized by Davis [8] into five
types as i) Math-based, ii) Informal, iii) Large-scale, iv) Web mining, and v)
Crowd Sourcing, then he discussed pros and cons of each approach. In this re-
search, our approach is classified as Informal and Large-scale, while DBpedia
can be classified into the approach of Crowd Sourcing.
    The role of verb is not seriously regarded in action planning so far. Action
is just called operator in the context of old AI planning. Cognitive Linguistics
pays more careful attention on the relation between verbs and objectives. In
this research work, we picked up several verbs such as ‘see’, ‘eat’, and ‘buy’ in
order to plan actions according to the use-case scenarios, and the relation of
such verbs to objectives is realized in our facility ontology and service ontology.
See the details in the following section.
    Schank addressed eleven primitive actions in Conceptual Dependency the-
ory [9]. He suggested us verbs may be categorized in hierarchy structure. Schank
also invented the idea of script that explains typical stereotyped human behav-
iors at restaurants or fast food shops or other facilities [10]. We also defined
typical behavior for users in our facility ontology and service ontology, where a
noodle shop as food facility provides noodle food service, and the noodle food
service is composed of eat action and food noodle as objective.
    Frame theory by Fillmore is a theory for Natural Language Understand-
ing [11]. In Filmore’s semantic frame, verb ‘buy’ is described by other frames
such as ‘goods’ as object, ‘buyer’ as subject, in addition to other frames ‘seller’
and ‘money’. Extending semantic frame theory, Fillmore developed Case Gram-
mar, in which a sentence is analyzed with two type cases, surface cases and
deep cases. Fillmore addressed several deep cases, Agent, Object, Instrumental,
Result, Locative, etc. In this work, we also adopted case grammar for text pro-
cessing, because Japanese is very compatible to Case Grammar, and it is easy
to apply surface cases to Japanese particles. See the details in Section 6.
    Levin [12] published a resource materials on the English verb lexicon, in which
verbs in English are classified into a number of verb classes (by attributes), but
there is no hierarchy of classes and no ontological or taxonomic description about
verbs, and less descriptions on the relationship to objectives.
    Generally, we have a number of aspects in dialogue. Searle described the
mechanism of human speech interaction and addressed the Speech Act theory
[13]. In his theory, he follows the idea of John L. Austin and elaborated ten
speech aspects of illocutionary act, that is a terminology for intensive action by
speech, i.e., request, question, assert, state, affirm, thank, advice, warn, greet, and
congratulate. Today, chat should be taken account of in addition. In this prelim-
inary work, we took account of only request. See the details of text processing in
Section 6.


4     Ontologies for Facility, Action Target, and Service
4.1    How to Make Facility Ontology
Instead of directly searching individual facilities like Ueno Zoo or individual
shops like Yodobashi Akiba store (a home electric appliance mass retailer in
Japan), we considered classes of facilities like zoo or home electric appliance
mass retailer to make the system scalable, then made a facility ontology that
contains typical facilities and we defined typical users’ behavior at such facilities
like “a user sees animals in a zoo” or “a user buys a household appliance at
a home electric appliance mass retailer.” Even if we accidentally fail to guide
an actual facility that satisfies user’s special requests, such a problem will be
solved with the development of richer and more specific datasets that includes
individual facilities.
    The facility ontology is constructed mainly by extracting facility classes re-
lated to leisure and meals in Linked Geo Data (LGD). LGD constructs a shallow
class hierarchy from tags attached to the nodes and ways of OpenStreetMap
(OSM). Therefore, LGD classes makes it easy to incorporate new facilities and
new facility types.
    On the other hand, as a result of adopting LGD / OSM, duplicates of classes
due to notation fluctuation of tags and the low coverage rate of actual facilities
at the instance level could be a big problem. However, we think this approach
is the best for our purpose in our best knowledge, because the LGD / OSM is
the largest facility data that is freely available at the present. Also note that
actually it is impossible to measure how much the existing facilities are covered
in reality. Regarding duplicates of classes in LGD, we select an entity as primary
class that has both the most information-rich descriptions on the OSM and a
large number of instances, then the rest are associated with owl:equivalentClass
to the primary class.
    The following shows an example of zoo class in the facility ontology. The
meanings of Japanese words are added here in English as turtle comments for
readers. Both a service of “see animal” and “pay admission fee for cultural facil-
ity” are actually described in the service ontology as subclasses of “see” service
and “admission-viewing-gaming” service. Note that each service is described as a
pair of an action and an action target, which users can perform. In this paper, we
manually acquired and created service knowledge of facilities within the scenarios
as necessary. See the statistic numbers in Table 1. As shown below, the lgdo:Zoo
class is linked to the dbo:Zoo class in DBpedia Ontology to make possible to
search related facility instances in DBpedia Japanese. The dbo:Zoo already has
a link to Wikidata’s wikidata:Q43501. Thus, it can be easily expanded when
Wikidata is added.

lgdo:Zoo a owl:Class;
  servicevoc:dbpediaClass dbo:Zoo ;
  servicevoc:provideService [ servicevoc:hasService [
      servicevoc:action action:払う;                   # pay
      servicevoc:target target:文化施設入場料 ], [ # admission fee
                                            # for cultural facility
      servicevoc:action action:見る;                   # see
      servicevoc:target target:動物 ]] ;               # animal
  rdfs:subClassOf servicevoc:Facility .

4.2   How to Make Service Ontology
In the facility ontology, a number of services corresponding to distinct facilities
come up with common abstract services. For example, both museums and art
museums have the same service of “paying entrance fee for cultural facilities”. In
addition, there are hierarchical relationships among users’ action targets, then
we have a similar relationship between services. For example, “seeing animals”
can be regarded as the top of “looking at a lion”. We constructed an ontology of
services apart from facility classes, so that services are independently recogniz-
able, and it enabled us to expand the performance of inference by applying the
hierarchy of services. In this paper, the part of service ontology is constructed
by using the Classification in the Household Survey of the Ministry of Internal
Affairs and Communications. The top of service ontology is the ‘facility service’
and it is related to aspects of two types of behaviors, namely, ‘purchase service’
focused on purchasing behavior, and an ‘activity service’ focused on the other
behaviors at facilities. The following shows an example of ‘purchase service’ on-
tology entries.

      service:食料_サービス a owl:Class;        # food service
        rdfs:label "食料_サービス";
        servicevoc:action action:買う;      # buy
        servicevoc:target target:食料;      # food
        rdfs:subClassOf service:購買_サービス . # purchase service

      service:肉類_サービス a owl:Class;        # meat service
        rdfs:label "肉類_サービス";
        servicevoc:action action:買う;      # buy
        servicevoc:target target:肉類;      # meat
        rdfs:subClassOf service:食料_サービス . # food service


4.3   How to Make Target Ontology

For the sake of systematical description of actions and action targets, we used
the Household Income Balance Item Classification List (January, 2015) of the
Statistics Bureau of the Ministry of Internal Affairs and Communications, of
which items of statistics data are used to describe purchasing behavior at facili-
ties. User’s behavior at facilities can be divided into purchasing behavior (such
as buying something or paying for some benefits as service) and the other actions
(see, eat, drink, etc.). This classification is based on a hierarchical structure of
action targets as users’ behavior as consumer, so it is possible to consider cooper-
ation with statistical data in future, starting with purchase actions. For actions
and action targets other than purchasing behavior, we used Japanese WordNet,
because we want to use WordNet’s knowledge on the relationship between each
verb as action and each noun as an action target. For instance, we made Action
Target Ontology as follows.

target:動物 rdfs:label "動物";                    # animal
  servicevoc:wordnet wnja11instances:word-動物 .

target:食料 a owl:Class; rdfs:label "食料";       # food
  servicevoc:wordnet wnja11instances:word-食料 ;
  rdfs:subClassOf target:購買対象 .               # purchase object
4.4   LOD, Ontologies, and Statistics
All LOD datasets and ontologies in this study and their statistics data are de-
scribed in Table 1.

             Table 1. Outline of Prepared Datasets and Used Datasets

                 Dataset                Version Num. triples Num, classes used
               Fact Dataset
      DBpedia core+en                2016-04-01 1,131,657,931     -        △
      DBpedia Japanese               2017-02-20 113,299,748       -        ○
      LinkedGeoData                  2015-11-02 1,216,560,762     -        ○
             General Ontology
      DBpedia Ontology               2016-11-01         30,793        758 ○
      LGD Ontology                   2014-09-09         24,530      1,200 ○
      Japanese WordNet               2013-06-26      4,003,288     57,238 ○
      Japanese Wikipedia Ontology 2013-11-07        21,863,327   166,397 -
      YAGO                                 3.0.2 1,001,461,792 5,130,031 -
      OpenCyc                        2012-05-10      5,783,451   233,644 -
      UMBEL                                  1.5       392,728     33,686 -
             Service Ontology
      Facility Ontology              2017-02-20          3,257        418 ○
      Service Ontology               2017-02-20          3,933        750 ○
      Action Target Ontology         2017-02-20          2,030        622 ○
      Action Ontology                2017-02-20            153         55 ○
      subtotal of Service Ontologies                     9,373      1,845
      Total                                      3,495,087,723 5,624,799




    The service ontology at the bottom of the table is the ontology we constructed
this time, as explained in the above.
    While the number of data with longitude and latitude were respectively
26,351,904, 100,139, and 1,014,836 for LinkedGeoData, DBpedia Japanese, and
DBpedia respectively, the number of geodata, of which each is close to rectan-
gle, in domestic portion excluding Hokkaido, is respectively 538,878, 67,199, and
15,409.


5     Building Knowledge Graphs
We have collected a number of open knowledge resources as shown at the upper
part of Table 1, and all of them are stored in one RDF store. However, at the time
of this writing, we have actually used only DBpedia Japanese, LinkedGeoData,
Japanese WordNet, and DBpedia Ontology as open datasets. Wikidata is not
stored because of the capacity.
    The system used one endpoint built with one dedicated RDF store.
6     Reasoning and Q&A Process
In this preliminary research, we process natural sentences only within the range
expected at use-cases. Furthermore, in this paper it is assumed that the input
is transcribed as text instead of speech.

6.1   Process Flow and Reasoning
Work flow of this system is described as follows (see, Figure 1).
1. Input a text of user’s requests.
2. Perform the morphological analysis for the input text.
3. Perform the case analysis starting with surface cases to deep cases.
4. Translate the requests into SPARQL queries.
5. Obtain the reply of SPARQL queries.
6. Generate the answering text from the obtained reply.
7. Output the recommendation.




                         Fig. 1. Data Flow in Processing



   Japanese is a kind of agglutinative languages and a Japanese sentence is
written without a space left among phrases and words. A noun phrase is com-
posed of a noun and a particle, a verb phrase is composed of a stem of verb and a
grammatical conjugation. So, morphological analysis is requisite in Japanese text
processing in order to separate a sentence into phrases and words. Furthermore,
particles attached to nouns decide the grammar case. For example, in response
to an user’s input “ライオンが見たいな (I want to see a lion)”, the morphological
analysis and shift-reduce method changes the Japanese sentence into the form of
((な (pos info) 8) ((たい (pos info) 6) (見 (pos info) 5)) ((が (pos info) 4) (ラ
イオン (pos info) 0))), here (pos info) stands for a Part-of-Speech information
of each, then case analysis produces the result such as Subject:NIL, Verb:(見
る (pos info) 5), Object:(ライオン (pos info) 0), toPlace:NIL, fromPlace:NIL,
Tool:NIL. Part-of-speech information obtained from morphological analysis is
effectively used in various ways. For example, if there is an auxiliary verb ‘たい
(want)’ next to a form of a behavioral verb such as ‘見る (see)’ or ‘食べる (eat)’,
the whole sentence is interpreted as request. Thus, a request of seeing a lion is
captured and transformed into a SPARQL query to the endpoint.
    From the interpretation of request (see lion), the system searches facilities
that can see a lion, using action target ontology and facility ontology. However,
we have no common sense as LOD that a lion is in a zoo. When searching fails
here, WordNet is used to generalize the target to more abstract ones by searching
hypernym relations in WordNet until animal is found.
    The SPARQL search picks up a number of facilities that are located near the
current location, and the closest one to the current location is chosen outside of
SPARQL search.


6.2   Inference with SPARQL

Initially, we attempted to make a plan by introducing IS-A logic function into
planning based on classical state space reasoning and backward reasoning [14].
However, more than it, searching combined ontologies using one SPARQL query
easily enabled us to retrieve acceptable instances of appropriate facility from
the action target ontology and the facility ontology without any problems in
execution speed. The LGD class according to the user’s request from the facility
ontology can be found, and once the LGD class is known, SPARQL allows direct
retrieval of the facility instance within the LGD. If there is a DBpedia class linked
from LGD, DBpedia Japanese is also automatically searched in SPARQL queries.
The current system consists of RDF Store search and inference for interpretation
of user’s requests. This configuration is beneficial at usability and re-usability.
Based on SPARQL search and open resources, it is possible to expand and
refine ontology without touching the inference engine of the planning system
in applications. It is meaningful for practical application of reasoning by large
amount of data.


7     Example of Execution

The following shows an example of execution by this prototype system, see the
added comments translated into English for readers.
SYSTEM(4): (eliza)
system> スポーツがしたいな。そのあと、温泉に行きたい。
;; I want to enjoy some sport, after that, I want to go to hot spring.
現在地はトヨタ東富士研究所です。
;; the current location is Toyota Higashfuji Institute.
スポーツをする場所を探します。; searching a location for sports
......
一番近くの場所を案内します。 ; guiding the nearest place
距離は 13.37621km です。         ; the distance is 13.37621km
場所:沼津市営球場                 ; place: Numazu City Ball Park
緯度:35.1125                 ; longitude
経度:138.863                 ; latitude
URL:"http://linkedgeodata.org/triplify/node2877270449"
現在地は (35.1125 . 138.863) です。; the current location is (35.1125 . 138.863)
温泉に入る場所を探します。              ; searching a location for hot spring
......
一番近くの場所を案内します。 ; guiding the nearest place
距離は 10.426165km です。        ; the distance is 10.426165km
場所:伊豆長岡温泉                 ; place: Izu-Nagaoka Hot Spring
緯度:35.0353                 ; longitude
経度:138.929                 ; latitude
URL:"http://ja.dbpedia.org/resource/伊豆長岡温泉"

    Searching for a facility in the vicinity of the current location, the Toyota
Higashifuji Institute, the system made a recommendation to go to Numazu City
Ball Park, then go to Izu-Nagaoka Hot Spring, in response to a request to go to
a hot spring after enjoying some sport.
    Here the command ‘eliza’ is named for just representing a mimic of Eliza
dialog system [15], that is the first dialog system in AI history. While this proto-
type of action planning by using open knowledge sources and SPARQL queries
is widely applicable to various kind of applications, yet there is not enough as
intelligent agent, because it has neither short-term nor long-term memory like
original Eliza. Making more intelligent agent remains in future work.


8   Discussion

In this work, we captured knowledge about our world into three layers, i,e.,
factual knowledge, general knowledge, and empirical knowledge. The factual
knowledge includes objective information on individual events and matters. On
the other hand, the general knowledge is not information on individual events
and things, but rather description of relationships among them in addition to
the abstract descriptions of events and things. It is regarded as objectively valid
by most people or as social agreement. The empirical knowledge is a specific
knowledge that does not go into general knowledge in society, such as personal
knowledge which are agreed only by less people. For example, suppose a very
delicious hamburger made by a fast food shop located at a place, the information
on this shop’s address is factual knowledge, the knowledge of classification on
fast food shop is general knowledge, and knowledge such as a hamburger made
by this hamburger shop is delicious is empirical knowledge.
    As shown in Table 1, most of LGD / OSM is factual knowledge and it is
categorized to factual dataset, but a part of LGD / OSM is categorized into
general knowledge. DBpedia contains both fact data and general knowledge.
However, WordNet contains general and empirical common knowledge.
    In this preliminary research, the following issues are suggested.

1. It is necessary to understand data characteristics of coverage and granularity
   of each dataset, but it is generally hard for large datasets. At this time, we
   firstly made a utilization plan on the whole data set, after we examined the
   availability of actual data on the premise of these use-case scenarios.
2. Generally, it is tough work to find out correct relations between datasets.
   While simple string matching allows us an automatic matching process, the
   ontology mapping cannot be avoid human power at the present. While the
   accuracy of this mapping greatly affects the result, mechanical matching pro-
   cessing is difficult. In addition, we built intermediate ontologies and mapped
   them to LOD datasets, but building ontology is generally not easy for a
   novice.
3. Since DBpedia and LGD are datasets made by crowd sourcing, we cannot
   expect the completeness and validity of them. Missing or biased data is still
   problematic at reasoning. Actually, we found a closed food shop as results.
   At this time we attempted to eliminate errors as soon as it was found, but
   we need to think about some tools for (semi) automated error checking.
4. The inference procedure was designed according to these use-case scenarios.
   For other problems, different datasets and different work flows may be used.
   For example, it depends on features of a target problem about how the
   balance should be taken between general knowledge and fact data to solve
   the problem.


9   Conclusion

In this preliminary research, we made a prototype of action planning system for
events of everyday life and world, based on open knowledge of LOD as fact data
and taxonomy as common knowledge. We utilized a number of large-scale open
databases and knowledge-bases. We found that we had already abundant knowl-
edge about the everyday life and world as diverse open knowledge resources. This
condition is very different at the era of Good-Old-Fashioned-AI (GOGAI) before
the Web age and LOD. However, we also found that we needed the additional
general and common knowledge that connects such different open resources in
reasoning action plans with SPARQL endpoints. It is obvious that it will be
necessary to make open knowledge more available not only in the verification
and validation for each, but also in the combinations of them for applications.
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