HAKONIWA- Application Development Environment forInternet CAR systemHitoshi Haruta

Tetsuji Hino, Masaaki Sato, Keisuke
UeharaNEC Soft,Ltd.
1-18-6 Shinkiba, Koutou-ku Tokyo 186-8680,
JAPAN
Phone:+81-3-5569-3225 FAX:+81-3-5569-3289
E-Mail: haruta@mxf.nes.nec.co.jp

Keio University Graduate School of Media andGovernance5322 Endo, Fujisawa Kanagawa 252-8520,
JAPAN
Phone: +81-466-49-1100 Fax:
+81-466-49-1395
E-Mail:{zenigata|saikawa|kei}@sfc.wide.ad.jp

Ryota Horiguchi
i-Transport Lab. Co., Ltd.
2-12-404, Ageba-cho, Shinjuku-ku, Tokyo
162-0824, JAPAN
Phone: +81-3-5261-3077
FAX:+81-3-5261-3077
E-mail: horiguchi@i-transportlab.jp

Kei Imamura
Mitsubishi Research Institute, Inc.
2-3-6, Otemachi, Chiyoda-ku, Tokyo 100-8141,
JAPAN
Phone: +81-3-3277-0780 Fax:
+81-3-3277-3462
E-Mail: kei@mri.co.jp

Hideki Sunahara
Nara Institute of Science and Technology
8916-5 Takayama-cho, Ikoma, Nara 630-0101,
JAPAN
Phone: +81-743-72-5150 FAX:
+81-743-72-5149
E-Mail: suna@wide.ad.jp

Hirokazu Akahane
Chiba Institute of Technology
2-17-1 Tsudanuma, Narashino, Chiba275-8588, JAPAN
Phone: +81-474-78-0444 FAX:+81-474-78-0474

ABSTRACTInternet CAR system is a common ITS platform which connects a human, a road anda vehicle on the Internet. Vehicle Environmental Applications will have more importancein Internet CAR. Vehicle Environmental Applications can make use of environmental
ﬂuctuations of vehicles. With this feature, developments of Vehicle Environmental Applications are far more diﬃcult. Application developers need environmental information
during their development process. So far, no eﬀective method is developed. This paper
proposes the application development environment for Vehicle Environmental Applications. In this development environment, applications can virtually obtain environmental
information and behave as it is in the real situations.

INTRODUCTION
In this paper, we propose Application Development Environment for Internet CAR
system, which called HAKONIWA.
The Internet CAR Porject [1] and Internet ITS Consortium[2], is working to connect
roads, vehicles and humans by the Internet.

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And their goal is creating the ITS platform which all vehicles were connected by theInternet. The main feature of the Internet is end-to-end communication on widely deployed network infrastructure on open platforms. By constructing road-vehicle-human
network by the Internet, new application and sevices can be developed in open platform.
Deploying Internet devices in vehicles should make application development costs
cheaper since these applications and devices would not only be developed for telematics. Any applications which exist on current internet can be applied for Internet CAR
system. Existing internet applications, however, do not consider to behave in vehicle
environment. Applications which can perform in vehicle environmet will gain more importance in Internet CAR system. In this paper, these applications are called Vehicle
Environmental Applications.
In this paper, we propose HAKONIWA, the application development environment
for applications on the Internet CAR. In HAKONIWA applications can obtain environmental ﬂuctuations virtually.
The following sections are organized as follows; we ﬁrst outline in Section 2 theassumed environment for Internet CAR system, and requirements for HAKONIWA.
Then, Section 3 details the system overview of HAKONIWA. Section 4 describes theevaluation of HAKONIWA.

VEHICLE ENVIRONMENTAL APPLICATIONSIN INTERNET CAR
This section illustrates the overview of vehicle environmental application and its development. We show the diﬃculty in developing the vehicle environmental applications.

Vehicle Environmental Applications
Currently about 120 sensors are equipped on vehicles in order to collect ﬂuctuationsof environment around vehicles(e.g., GPS, Velocity sensor, Temperature sensor and soon). Moreover, network condition can be obtain from communication devices.
Vehicle Environmental Applications will make use of these ﬂuctuations of environemntal information.Vehicle Environmental Applications obtain environmental information,and behave accordingly. Vehicle Environmental Applications are categorized as follows.
• Observation Applicatons
Observation Applications will behave on the Internet side and observe the motionof vehicles. For example, the Probe Car system collect velocity information andgeographical location, and then generate traﬃc information without any roadsidedevices.
• In-Vehicle Applications
In-Vehicle Applications will behave in the vehicle. Main purpose of In-Vehicle
Applications is assistance of drivers and delighting the passengers. For exsample,
video streaming application which dynamically adopt its quality according to thecondition of communication network.
Figure 1 illustrates the abstract of Vehicle Environmental Applications. Any Vehicle
Environmental Application, whether Observation one or In-Vehicle one, behave accordingly to the environmental information. Vehicle Environmental Applicaions can obtain2

Figure 1: Vehicle Environmental Application
environmental information from sensing devices in the vehicle(Wiper, Break, GPS andso on) .
For example, the Probe Information systems[3], one of the Observation Vehicle Environmental Applications, collect information of vehicle environment from travelling
vehicles and creates new information;traﬃc infomations weather information and so on.

Development Processes of Vehiclne Environmental Applications
In the developement process of Vehicle Environmental Applications, special development environment is indispensable to application developers.
For a development of any internet applications including Vechicle Environemtal Applications, application developers usually take 3 steps , 1)Design and Implementation,2)Decision of Parameters, 3)Veriﬁcation by Field Tests. In the ﬁrst step, developers
ﬁgure out the system overview and detailed application behaviors, and then implement
these behavior accordingly. As the second step, they decide various parameters of its
behavior. For example, initial data sending bit rate or limit wave strength for handover have to be decided. At the last step, an application behavior is tested in real but
restricted situation.
Although these steps can be taken on the desk, development of Vehicle Environmental Applications 2nd and 3rd steps are more diﬃcult than existing applications. Because
behavior in Vehicle Environmental Application depends on vehicle environmental information. Thus, development environments for Vehicle Environmental Applications isrequired.
In the development environment, vehicle environments are simulated and application
behavior is emulated. The development environment provides easier and more close-toreal testing environment for vehicle environemntal application developers.

CONCEPT OF HAKONIWA
In this section, we propose overview of HAKONIWA. HAKONIWA is our developemnt environment for Internet CAR system.

Overview of HAKONIWA

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As mentioned earlier, development of Vehicle Environmental Application is morediﬃcult than ordinary internet application. Thus, we propose development environment
which is called “HAKONIWA”, meaning small boxed garden in Japanese.
In real situation, Vehicle Environmental Applications obtain environmental information from sensing devices equipped to the vehicle, and behave accordingly to theseinformation. In the development environment, developing applications also require environmental information and should behave accrodingly.
Figure 2 shows the relation between Vehicle Environmental Applications and Environmental Informations. In HAKONIWA, an environmental information can be obtained from simulation modules instead of sensing devices, so that applications canbehave accrodingly to the information.
With HAKONIWA, applications can be developed in the close-to-real situations,because vehicle situations are simulated and emulated in HAKONIWA.

Figure 2: Vehicle Environmental Application and Environmental Information
In Figure 2, environmental information are stored in Vehicle Information Database.
This is just a example of a interface between environmental information and applications. Other style of interface also could be applied. But interface should be stardarized
in future for applications to access every vechiles equally.

Requirements
HAKONIWA must meet the following three requirements, “In-Vehicle Consistency”,“In-Traﬃc Consistency” and “Flexible Conﬁguration”.
• In-Vehicle Consistency
The environmental information generated by simulation modules should be consistent in the vehicle. For example, when a velocity is 70km/h, geographic information must be changing by that velocity.
• In-Traﬃc Consistency
Environmental information of vehicles in the same traﬃc must not contradict eachother. When one vehicle turn on its wiper for the rain, other vehicles in the sametraﬃc must also turn on thier wiper. Otherwise wipers are assumed to be out oforder.
• Flexible Conﬁguration
In order to support any developments of Vehicle Environmental Application,
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HAKONIWA should simulate any possible environments. There could be a various situation, for example, driving on a highway, or at a parking lot, or driving
under heavy traﬃc jam.
If HAKONIWA does not meet these requirements, it is hard for developers to use
HAKONIWA. Moreover applications which were developed in HAKONIWA will not
behave as developers had expected.

DESIGN AND IMPLEMENTATIONThis section describes system design of HAKONIWA and its implementation.

Design approach for HAKONIWA
There is two approach to facilitating the development of Virtual EnvironmentalApplicaitions. One approach is to setup the special device which can generate environmental information as a real vehicle. And second approach is to provide application
running environment with environmental information.
Figure 3 illustrates the two approaches for HAKONIWA. In the ﬁrst approach(inthe right), an application connects to the special device and obtain environmental information from the device. The special device include some simulation modules. In thesecond approach(in the left), HAKONIWA is the development environment for vehicle
environmental applications. Applications can behave on the environment. In this development environment, applications can behave like as real situation, because vehicle
behaviors and environmental ﬂuctuations are simulated and emulated.

Figure 3: Two approaches for HAKONIWA

We compare these two approachs and, choose the second approach. The ﬁrst approach require one PC for one application. When we develop system with many vehicles behaving simultaneously, we must setup many PCs. In development environment
approach, we only need a PC. Currently, we cannot develop applcations on diﬀerent
architecture at the same time.

DesignHAKONIWA consists of two modules. One is for simulating the vehicle environment,
and another is for emulating the application behavior in the vehicle.
To meet requirements, we propose Virtual Vehicle Model. In Virtual Vehicle Model,
the vehicles are abstracted as a Virtual Vehicle and vehicle surroundings are abstracted5as Environment Map. Virtual Vehicle represents a single vehicle in HAKONIWA. A
developing application is installed to and running on the Virtual Vehicle and obtainsvehicle environmental information through Virtual Vehicle. Environmental informationof each Virtual Vehicle is simulated by Environmental Maps.

Development of Virtual Vehicle
Virtual Vehicle has 2 feature, ﬁrst one is “Emulator of environmental information”
and second one is “Running environment for application”.
Emulation
Environmental information of vehicles is generated by other simulation modules (detailed in later). In order for applications on the vehicle to obtain environmental information of the vehicle, all information belongs to the vehicle is identiﬁed by the VirtualVehicle. And also, Virtual Vehicle oﬀers the interface between applications and information. Applications obtain environmental information of its vehicle through theinterface. Detail of the interface depends on the standard interface in a real situation.
Figure 4 shows the system structure of Virtual Vehicle. In the ﬁgure, some simulation modules generates the environment information. And applications obtain theseinformation through Application Interface(API). Applications on the Virtual Vehicle
sends and receives data through the virtual interfaces(I/F). Detail of the virtual interface is described in next part.

Figure 4: System Structure of Virtual Vehicle

Running Environment
In HAKONIWA, applications are installed to the Virtual Vehicle so that many vehicles could be simultaneously developed. Each vehicle have various applications, fromstreaming application to electoric toll collection applicaton. These applications must
behave independently. In the implementaion of this research, each Virtual Vehicle has
its own Java VM(Virtual Machine) to enable these application behavior.
Moreover, running environment must provide communication network to the Internet. When applications on the Virtual Vehicle communicate via the Internet, a commu6

Bandwith:
5Mbps
Delay:+50ms
Packet Loss Rate: 10%

VirtualI/F 1
VirtualI/F 2

NetworkFilter
Bandwith:
10MbpsDelay:+20ms
Packet Loss Rate: 5%

REAL I/FInternet

VirtualI/F 3

Figure 5: Communication Network Filter
nication network must be emulated as its environment. Emulation of a communication
network is achieved by a communication network ﬁlter.
Virtual Vehicles have functions to sending and receiving application data via its
virtual network interfaces. Because these virtual network interfaces are originally underconstant condition, network condition also be emulated in HAKONIWA.
Figure 5 illustrate the Communicatin Network Filter. In this ﬁgure, some virtualnetwork interface is attached to the real network interface and Network Filter stands
between virtual interface 1, 2 and real interface. When Virtual Vehicle sends data to
the Internet using virtual interface 1, Network Filter modiﬁes communication quality.
Concretely, data is queuing in the ﬁlter so that delay is modiﬁed or the amount ofpassing data is suppressed to the limited bandwidth. Kinds of items which can be
modiﬁed in Network Filter are depending on the implementation of Network Filter.
In the implementaion, we use DUMMNET[4] as a network communication ﬁlter. InDUMMYNET, bandwidth, delay and data loss rate can be emulated.

Development of Simulation Modules
The vehicle environmental information are generated by simulation modules, suchas traﬃc simulator or weather simulator, developed in their own research ﬁelds. Thus,
accuracy of simulation in HAKONIWA is beyond our scope. If developer needs moreaccuracy in HAKONIWA, more accurate simulator is required.
Travel information of vehicles is simulated by traﬃc simulator. In this paper weuse the traﬃc simulator based on SOUND(developed in University of Tokyo.). SOUND
simulate the travel of each virtual vehicle. Travel information consists of Longitude,Latitude, Speed and Direction.
Communication Environment is simulated by the relation of position of vehicles andwireless access points. Communication Environment is consisted of 3 parameters, 1)
Bandwidth, 2) Round Trip Time, 3) Packet Loss Rate.
Each simulation result is transferred to the map. Information can be identiﬁed bygeographical position(Longitude, Latitude and Altitude). As for the weather simulation
map, weather condition can be obtain at every geographical position. By transferringto the map, removing and adding of environmental information becomes far easier
because all diﬀerent simulator results can be treated by geographical position. Therefore
conﬁguration of HAKONIWA is easy and can be available at many situation.

EVALUATIONAs an evaluation, a sample application is developed in HAKONIWA to evaluate theeﬀectiveness. As a sample application, we have developed the primitive application,7

just communicate to the server on the Internet. In this application, 100 vehicles and 15
Wi-Fi access points are conﬁgured as left side of Figure 6.
Then we have measured the ﬂuctuation of round trip time between vehicles andthe server. Right side of Figure 6 shows the ﬂuctuation of round trip time, and thisﬂuctuation indicates that the movements of virtual vehicles are simulated and emulated.
Thus, application developers can develop application with these ﬂuctuations. Again,
accuracy of measured round trip time is beyond our research.
(msec)

80(degree)
35.25
35.24

70

35.23

60

35.21

RTT

Latitude(N)

35.22

50

35.20
35.19

40
35.18
35.17

30
35.1635.15
136.84(degree)
136.86136.88136.90136.92136.94136.96136.98

20137.00

0100

200

Longitude(E)

300

400

500
600
Sequence Number

700

800

900

1000

Figure 6: Conﬁguration of Evaluation Environment and Evaluation Result

CONCLUSION
In this paper, we described the overview of HAKONIWA, application development
environment for Internet CAR systems. We have seen the diﬃculty in developmentsof Vehicle Environmental Application in Internet CAR system, especially on testingprocess. To facilitating the development, we propose HAKONIWA which simulate andemulate the vehicle environment and oﬀers the useful testing platform of application
behaviors.
By HAKONIWA, developments of application in Internet CAR can be more eﬀective,
since applications can be tested and validated only with HAKONIWA without need fora real testbed nor special hardware.

References[1] Keisuke UEHARA, Yasuhito WATANABE, Hideki SUNAHARA, Osamu NAKAMURA, and Jun MURAI. InternetCAR -Internet Connected Automobiles-, 1998.
[2] Internet ITS Project. http://www.internetits.org/.
[3] Koji Wada. Research, Development and Field Testing of The Probe Car Information
System(III), Nov 2003. ITS World Congress 2004.
[4] Luigi Rizzo. Dummynet: a simple approach to the evaluation of network protocols.
ACM Computer Communication Review, 27(1):31–41, 1997.

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