Search in Publications

Found 6289 publications

Method for benchmarking single board computers for building a mini supercomputer for simulation of telecommunication systems

Sándor Répás Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 246-251

Description:

Parallel Discrete Event Simulation (PDES) with the conservative synchronization method can be efficiently used for the performance analysis of telecommunication systems because of their good lookahead properties. For PDES, a cost effective execution platform may be built by using single board computers (SBCs), which offer relatively high computation capacity compared to their price or power consumption and especially to the space they take up. A benchmarking method is proposed and its operation is demonstrated by benchmarking six different SBCs, namely Banana Pi, Beaglebone Black, Cubieboard2, Odroid-U3+, Radxa Rock Lite and Raspberry Pi Model B+. Their benchmarking results are compared to find out which one should be used for building a mini supercomputer for parallel discrete-event simulation of telecommunication systems. The SBCs are also used to build a heterogeneous cluster and the performance of the cluster is tested, too.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296261

Modelling of virtualized servers

Akos Kovacs Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 421-425

Description:

The virtualized systems are one of the key elements of the next generation IT infrastructures. Modeling it will prevent mistakes, and oversized management. Opennebula is one of the most current open source cloud management solutions. Together with Haizea, they are a powerful tool to model and manage a virtualized infrastructure trough the API of Openebula. Haizea has multiple scheduler algorithms that are more effective than that of Opennebula. We performed several experiments to compare simulation and measurement capabilities of Haizea and we highlighted some difference between them which can be reduced if required.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296296

Stability analysis and performance comparison of three 6to4 relay implementations

Sándor Répás Viktor Horváth Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 82-87

Description:

During the IPv6 deployment there is a frequently occurring situation where two IPv6 enabled hosts need to communicate with each other over a network that supports only IPv4. Application of the 6to4 IPv6 transition method can solve this problem. The performance and stability of the different 6to4 relay implementations is a very important subject. We measured the performance and tested the stability of three open source 6to4 relay implementations under Debian Linux, OpenBSD and OpenWRT platforms. We present and discuss our results, analyze the stability of the 6to4 relay implementations and compare their performance metrics. Our measurements methods may be useful for other researchers, and our results may help the system architects to choose the appropriate solution.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296228

Modelling of virtualized servers

Akos Kovacs Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 241-245

Description:

The virtualized systems are one of the key elements of the next generation IT infrastructures. Modeling it will prevent mistakes, and oversized management. Opennebula is one of the most current open source cloud management solutions. Together with Haizea, they are a powerful tool to model and manage a virtualized infrastructure trough the API of Openebula. Haizea has multiple scheduler algorithms that are more effective than that of Opennebula. We performed several experiments to compare simulation and measurement capabilities of Haizea and we highlighted some difference between them which can be reduced if required.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296260

Application compatibility of the NAT64 IPv6 transition technology

Sándor Répás Tamas Hajas Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The proliferation of smart phones and other Internet capable devices together with the depletion of the global IPv4 address pool will be a huge driving force for the deployment of IPv6 in the forthcoming years. The communication of an IPv6 only client with an IPv4 only server is a typical practical task to be solved among the many issues of the co-existence of IPv4 and IPv6. The usage of DNS64+NAT64 may be a good solution if our applications can flawlessly work with it. As for NAT64 implementations, TAYGA running under Linux and Packet Filter (PF) of OpenBSD were tested with the following application level protocols: HTTP, HTTPS, SMTP, POP3, IMAP4, Telnet, SSH, FTP, OpenVPN, RDP, Syslog, BitTorrent, Skype and SIP. The client-server application protocols could traverse through the NAT64 gateway flawlessly but the peer to peer ones failed. In contrast to the results of other researchers, OpenVPN worked perfectly with NAT64.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296383

Port number consumption of the NAT64 IPv6 transition technology

Sándor Répás Tamas Hajas Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Due to the depletion of the global IPv4 address pool, the internet service providers will be able to supply their new clients with IPv6 addresses only in the near future. The application of the DNS64 and NAT64 technologies can enable the IPv6 only clients to communicate with the still dominant IPv4 only servers. However, the clients of certain applications such as HTTP and FTP use multiple sessions and thus they consume multiple ports. This phenomenon may cause a lack of ports situation at the NAT64 gateway. Therefore the port consumption of the different applications is an important design parameter of the NAT64 gateways. In this paper, the port consumption of different NAT64 compatible applications was measured. It was also determined what factors can influence the port consumption of a web or an ftp client. The detailed description of our measurement method is given. Our results can give a valuable help for careful design and configuration of a NAT64 gateway.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296411

Edge finite element method in case of high frequency simulations

Miklós Kuczmann Gergely Friedl

Publication Name: Pollack Periodica

Publication Date: 2015-10-01

Volume: 10

Issue: 3

Page Range: 59-70

Description:

The paper deals with high frequency simulations with edge finite element method realized with PETSc functions. The weak formulations of the high frequency simulations are derived from Maxwell's equations in frequency domain. To reduce the calculation time, the finite element method was implemented in PETSc environment. The realized simulation environments were validated with simple examples, which analytically can be calculated.

Open Access: Yes

DOI: 10.1556/606.2015.10.3.7

Closed loop control of finite element model in magnetic system

Miklós Kuczmann Daniel Marcsa

Publication Name: Pollack Periodica

Publication Date: 2015-10-01

Volume: 10

Issue: 3

Page Range: 19-30

Description:

This paper presents an axisymmetric formulation of the circuit-coupled finite element method embedded in closed loop control system. The controller checks the current of the coil of the magnetic system after each time step and controls the applied voltage to reach the steady state faster. The results of the voltage driven finite element model are compared with the results from the analytical model. The control parameters for the proportional-integral-derivative controller were estimated using the step response of the system. Furthermore, the results of the closed loop system simulation show why the model accuracy is important in the controller design.

Open Access: Yes

DOI: 10.1556/606.2015.10.3.4

Spatial stability analysis and global stability checks according to DIN EN 1993-1-1

Achim Rubert Ferenc Papp J. Szalai

Publication Name: Bauingenieur

Publication Date: 2015-10-01

Volume: 90

Issue: October

Page Range: 469-477

Description:

This paper presents the spatial stability analysis and global stability checks according to the "General Method" of DIN EN 1993-1-1/clause 6.3.4 for complete steel structures of thin walled open sections. This is a software based design procedure for evaluating the global eigen-solutions (eigenvalue acrop and eigen- shape) using integrated stability analysis and standard check. It is compared to the classical method using different calculation models as well as suitable software for stress analysis and the global spatial stability analysis and check. For the numerical analysis (as it is the crucial point of the method) the 14 DOF beam-column finite element of ConSteel is used. The two examples demonstrate the very safe and uneconomic restrictions of the German NA of clause 6.3.4. According the author's experiences and [16] it is not recommended to use them.

Open Access: Yes

DOI: DOI not available