Informatica 40 (2016) 285–289 285 
Virtual Assistant Platform 
Damjan Kužnar, Aleš Tavčar and Jernej Zupančič 
Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 
E-mail: damjan.kuznar@ijs.si 
 
Mihai Duguleana 
Transylvania University of Brasov Brasov, Romania 
  
Keywords: virtual assistant, SaaS, cloud application 
Received: June 15, 2016 
In this paper a novel virtual assistant platform is presented. The platform allows for easy creation, 
administration, and use of virtual assistants as additional services on websites and as a stand-alone 
application on mobile platforms. The implementation is based on the principle of Software as a Service, 
which significantly eases the installation and maintenance of the system and consequently reduces costs. 
Povzetek: Prispevek predstavlja platformo za virtualne asistente s poudarkom na spletni aplikaciji.  
 
1 Introduction 
Websites of major companies, various institutions, 
ministries and local administrations are often very large 
and have a very complex navigation structure, which 
makes it difficult for visitors to find the information they 
need. This problem is addressed by using the virtual 
assistant that helps the visitors find the information in 
natural language interaction. This kind of interaction 
hides the complex structure of the website in the 
background by providing the answers to the questions 
asked by the users. The use of virtual assistant allows 
visitors to search for information in a more natural way, 
which is especially important for less technically 
experienced users.  
In this paper we describe a virtual assistant platform 
that has been developed within the project Assistant [1] 
and is currently running more than 200 virtual assistants. 
Modern guidelines for development and software 
distribution were taken into account during the 
development and, therefore, the platforms was developed 
as a web service that runs in the cloud. The assistant 
represents the core for several ongoing projects dealing 
with tourists, municipalities and smart cities. 
2 Virtual assistant platform 
The service, which supports the creation, management 
and use of virtual assistants, has been developed on the 
principle of Software as a Service (SaaS) [2], which 
brings a number of benefits to customers. For example 
there is no need for the customer to purchase and 
maintain hardware, as software runs in the cloud, and no 
need for installing and maintaining the software. The 
system consists of the following components (Figure 1): 
 Web service in the cloud, which allows 
subscribers and end-users ease of use through 
the SaaS principle. 
 Web client that offers visitors of a website (end-
users) a rich graphic interface for 
communication with a virtual assistant. 
 Mobile clients in the form of mobile 
applications for the Android, iOS, BlackBerry 
and Windows Phone 8 platform, which enable 
for easy communication with a virtual assistant 
through mobile phones. 
 Administrative tools for managing virtual 
assistants, which allow customers to adapt their 
assistant to their individual needs. Tools are 
accessible through browser and are password 
protected. 
 
 
 
Figure 1: Virtual assistant platform overview. 
3 Web service 
Modularity, based on the principles of multi-agent 
systems [3], is an essential feature of the system. This is 
reflected in such a way that all system functions are 
implemented as independent modules (i.e. agents) and 
are able to communicate to each other. The system core, 
Web service 
[Saas] 
Administrative 
tools 
Web client 
[HTML5] 
Mobile clients 
[iOS, Android] 
End-users Customers 
286 Informatica 40 (2016) 285–289 D. Kužnar et al. 
which plays a similar role as the platform in multi-agent 
systems, provides the mechanism for communication 
between modules. The components of the system (Figure 
2) will be described below. 
 
Figure 2: The modular design of the system. 
3.1 Core 
The system core implements the following functions, 
allowing the modules to extend the basic functionality of 
the system: 
 Module management, including discovery, 
installation, updating, starting and stopping of 
the modules. The virtual assistant platform has a 
broad collection of modules available, which 
can be stopped if desired and thus speed up the 
system. 
 Registration and triggering of events, and 
registration of listeners that receive triggered 
events. The modules that trigger the events also 
define an arbitrary message structure that 
facilitates communication between modules. 
 RESTful API endpoints [4] definitions. Each 
module can define a function that can be used 
by end-users (through clients such as web client 
or mobile application). 
 Relational database access. The modules can 
store the necessary data into a relation database. 
 File system access. The modules that need to 
write and read files are provided with the 
required access rights. 
 
3.2 Modules 
The modules are independent functional components that 
extend the basic set of system capabilities. The core 
modularity allows the system to be extended to perform 
any task, however, this article describes the modules for 
the virtual assistant. Among the most important modules 
are: 
 qa: a module that receives questions from the 
user, forwards it to the answering modules 
(*_kb modules) and chooses the most 
appropriate response on the basis of a 
predefined procedure. 
 *_kb (eg. static_answer_kb): are modules for 
question answering that obtain answers in 
various ways. For instance rss_kb obtains 
answers from RSS feeds. 
 html5gui: a module that implements a web 
based graphical interface of a virtual assistant 
that users can interact with on websites. 
 applications: a module for managing 
applications (each module can define its own 
application) that virtual assistant provides to 
end-users in addition to the basic functionality 
of question answering. 
 
The existing system also hosts a number of other 
modules that provide answers to questions, facilitate the 
administration of the system, record the conversations 
between users and virtual assistant, etc. 
3.3 Messages 
Messages between the modules are transmitted when 
events occur within the system (e.g. when a question is 
received). Events can be registered and defined by the 
system core or by the modules that also define the 
structure of messages that will be sent when the event is 
triggered. The modules that have registered to that 
certain event receive the message. Those modules can 
then return the results of their processing back to the 
module that triggered the event. This enables the creation 
of complex processing procedures. 
3.4 REST API 
It is essential for the system to be able to communicate 
with the outside world. The REST specification [5] is 
used to create the API in the form of web services. All 
communication between users and the system goes 
through this interface, usually by the means of various 
graphical clients such as HTML5 client for websites and 
apps for mobile platforms. 
The most important functions provided by the API 
for virtual assistants are: 
 / ask (HTTP GET method) 
o Input parameters: 
 question: a question that we 
want the assistants to answer. 
 context (optional): the context 
within which the question was 
stated (eg. in applications and 
Virtual Assistant Platform Informatica 40 (2016) 285–289 287 
forms of municipal 
administration). Available 
contexts are obtained through 
the function / applications. 
o Response: 
 answer: answer of a virtual 
assistant in HTML format. 
 id: serial number of the 
answer, used for storing the 
evaluation and comments on 
the answer. 
 URL (optional): a website that 
is associated with the 
response. In the case of using 
a web client, the page will 
automatically open in the 
background, in the case of 
mobile applications the user 
can open a link in the 
integrated browser. 
 / vote / id / Up (HTTP POST method) 
o Input parameters: 
 id part of the route replaced 
with the value we received as 
part of the response of the 
function call / ask. It 
represents the number of the 
answer. Example: a call to / 
vote / 42 / up corresponds to 
the positive assessment of the 
response with the serial 
number 42. 
o This end point has no response 
 / vote / id / down (HTTP POST method) 
o similar to / vote / id / up, only that in 
this case a negative rating is recorded. 
In the case of multiple ratings for the 
same answer the most recent rating is 
stored. 
 / comment / id (HTTP POST method) 
o Input parameters: 
 id: number of the answer, 
which refers to a comment. 
 comment: comment on the 
answer. 
 name_and_surname: name 
and surname of the 
commentator. 
 email (optional): E-mail of the 
commentator. 
o This end point has no response 
 
All functions return the answers in JSON notation 
[6], unless the client defines the callback input 
parameter, in which case the answer is returned in 
JSONP notation [7]. 
4 Web client 
Web client is used to integrate the virtual assistant in the 
customer’s website. The assistant can appear 
automatically when the user visits a website or when the 
users clicks on a link that starts the assistant. 
On launch the web client (Figure 3) hovers over the 
content of the website and can be freely moved, allowing 
the user to continue browsing the web page in the 
background. Upon entering a question into the text box, 
the web client calls the web service to obtain an answer, 
displays it in the box below the input field and, if 
provided by the administrator, opens a webpage in the 
background that is related to the answer. In this way the 
web client displays a summary of the response and the 
visitor is invited to obtain more detailed information 
from the website in the background if he or she is 
interested. The Slovenian text in Figure 3: Who is the 
mayor? The major of Pivka municipality is Mr. Robert 
Smrdelj … 
 
Figure 3: Example of a virtual assistant for the Pivka 
municipality. 
In addition to the common virtual assistant 
functionality our platform also introduces the concept of 
applications or apps (accessible via the menu). Apps 
extend the basic functionality by enabling the use of 
specific services, e.g. ticket booking, or by focusing the 
search for answers on specific areas, e.g. the municipality 
contact information. Every customer can configure its 
own set of applications that it wants to offer to the 
visitors. 
5 Mobile apps 
Communication with the virtual assistant is also possible 
via mobile devices. The interface was adjusted for small 
screens, since the use of the web interface on mobile 
288 Informatica 40 (2016) 285–289 D. Kužnar et al. 
devices is awkward, especially for technically unskilled 
users. The mobile applications are important for several 
reasons. Mobility is the most important reason, since the 
user can use the assistant from anywhere, for example 
the user can ask “Where can I find a pharmacy?” when 
on the move in a municipality. In this case the assistant 
would find the information and offer to the user a list of 
pharmacies in a given municipality with the associated 
opening time. 
We have developed mobile applications for the two 
most popular mobile platforms: Android and iOS. Both 
mobile applications have the equivalent functionality to 
the web client graphical interface. Figure 4 shows the 
mobile applications screen design for Android platform. 
On the upper side of the screen is an input box where the 
user enters a question. Below the input field is the area 
for the answer, and underneath is the toolbar, where the 
user can find all the additional functionalities. The 
Slovenian text in Figure 4 corresponds to: Municipality 
Pivka; Do you have any question for me?; Ask me 
anything regarding municipality such as …. 
  
Figure 4: The main screenshot of the Android app. 
The functionality of mobile application is identical to 
the one in the web interface. The user enters the question 
in the search box and the application sends a query to the 
server that returns the most appropriate response. In the 
bottom toolbar there are additional assistant’s features 
such as: voting on a particular response (positive or 
negative); posting a comment on a particular answer; 
enabling speech synthesis; and allowing the users to 
select one of the applications offered by the assistant. 
Due to smaller screen sizes and data transfer 
restrictions on mobile devices some specific functionality 
is changed and adapted for mobile devices. The website 
that which contains more detailed information is 
accessible by clicking the "more…" button (in contrast to 
the web client that displays the website in the 
background). The app also contains the list of all 
available assistants and the user can select which 
assistant it wants to connect to. The list of assistants 
appears when the user opens the app for the first time but 
is also accessible via the app settings. Further mobile 
applications are adapted for the elderly and visually 
impaired, because in addition to speech synthesis it is 
also possible to increase the font size of the entire 
graphic interface. 
With the development of mobile applications we 
wanted to bring our virtual assistant platform even closer 
to users and to allow its use on a daily basis. 
6 Conclusion 
In this paper we presented a virtual assistant platform – 
framework for the creation and maintenance of virtual 
assistants. 
The service operates on the advanced web 
technology principles. The modular design enables to 
easily extended the service and add new functionality. 
Therefore, this service is suitable for a wide range of 
customers from municipalities and associations to public 
and private companies, which have their own specific 
requirements. 
7 Future work 
Due to its extensibility the developed virtual assistant 
platform can be used in various domains. We will exploit 
the modular architecture in several upcoming projects. 
Some of the existing modules will be reused, however, 
additional modules, specific to each project, will also be 
developed. In the following paragraphs the important 
projects will be described and their contribution to the 
virtual assistant platform will be presented. 
7.1 AS-IT-IC 
Austrian-Slovenian intelligent tourist information center 
(AS-IT-IC) project was accepted in the cross-border 
Cooperation Programme Interreg V-A Slovenia-Austria 
in the programme period 2014-2020. The project 
addresses the problem of not getting the desired 
information about natural and cultural heritage sites in 
the Slovenian-Austrian cross-border area in an integrated 
way. The goal of the project is to create a joint Austrian-
Slovenian center - an ICT supported network of service 
providers and tourist offices, municipalities, tourists and 
citizens to enhance continuous cooperation between 
them. Virtual assistant will be one of the ICT tools that 
will support the AS-IT-IC center. It will provide 
automatic answering in natural language to the questions 
related to the heritage sites and various other relevant 
tourist information, therefore, relieving the tourist 
information officers from providing answers to repetitive 
questions. The system will, in cooperation with human 
operators (tourist information officers), provide all the 
relevant tourist information and help the tourists plan a 
Virtual Assistant Platform Informatica 40 (2016) 285–289 289 
multiday trip in the Slovenian-Austrian cross-border 
area. 
During the project several new modules will be 
added to the platform: path planning interface; intelligent 
search over the content on natural and cultural heritage; 
automatic information extraction of knowledge from 
existing websites with relevant content, etc.  
7.2 eHeritage 
The goal of the project is the preservation and restoration 
of nation’s cultural heritage in electronic form. With the 
advancements in the field of virtual reality, intelligent 
systems, and AI methods, experts can now use 
augmented and virtual reality, 3D immersive graphics 
and intelligent GUIs to restore and reproduce historical 
sites. Interested individual can experience the historical 
sites in novel interactive and informative ways. 
Virtual assistant platform will provide the means for 
information retrieval from existing heritage sources in a 
natural language. During the project the following new 
modules will be added to the platform: natural language 
museum navigation; automatic extraction and intelligent 
content analysis of existing heritage databases, etc. 
 
8 Acknowledgement 
The work was co-funded by: the Slovenian Ministry of 
Education, Science and Sports through a public call for 
funding the development of e-services and mobile 
applications for public and private non-profit 
organizations 2012-2013 (JR ESMA JZNO 2012-2013); 
Cooperation Programme Interreg V-A Slovenia-Austria 
2014-2020, project AS-IT-IC; European Union’s 
Horizon 2020 research and innovation programme under 
grant agreement No. 92103, project eHERITAGE 
(Expanding the Research and Innovation Capacity in 
Cultural Heritage Virtual Reality Applications). 
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