• Journal of the Korea Society of Computer and Information
• /
• v.11 no.1 s.39
• /
• pp.157-165
• /
• 2006

This paper proposes a new output-buffered multicast ATM switch with tandem crosspoints switching fabric, named the MTCOS(Multicast Tandem Crosspoint Output-buffered Switch). The MTCOS consists of multiple simple crosspoint switch fabrics, named TCSF(Tandem Crosspoint Switch Fabric) , and concentrated output buffers for efficient multicasting. The TCSF resolves the cell delay deviation problem which the self-routing crossbar switches inherently have. Further, it offers multiple concurrent pathes from one input to multiple output ports. It also provides multi-channel switching by easy software configuration and has several desirable characteristics such as scalability, high Performance, and modularity. A shared traffic concentration and output queuing strategies of the MTCOS results in lower cell loss as well as lower cell delay time over a wide range of multicast traffic. Furthermore, it has lower hardware complexity than that of the SCOQ and Knockout multicast switch to achieve the same Knockout concentration rate as the conventional switches. It is shown that the proposed switch can be easily applied to design high performance for any multicast traffic by analytic analysis and computer simulation.

• Journal of Satellite, Information and Communications
• /
• v.5 no.2
• /
• pp.25-28
• /
• 2010

The need for multiband RF front-end in modern communication system is growing rapidly. For example, satellite system always uses a complex arrangement of frequency plans and consequently needs filters for each communication channel and it will be ideal to have a single filter module that does jobs of all those channel filters to reduce the size and payload of the system. In this paper, a new method to transform four-port self-feedback balanced dual-band bandpass filter into two-port is proposed. The two-port balanced dual-band bandpass filter which has baluns at the input and output ports and the fundamental frequency at 2.5 GHz and the first harmonic frequency at 5.7 GHz is fabricated and measured. Good agreement between measured and simulated results was achieved.

• The Journal of the Korea Contents Association
• /
• v.13 no.7
• /
• pp.1-8
• /
• 2013

As yet the use of 3D projection mapping facade has been limited to advertising and performance in the outside. And interactive elements are lacking. In this paper, propose a interaction system which control of projection mapping facade for multi-audience participation using smart devices. The system can be interaction for the multi-façade. And single or multiple can participate in the game. A user test based on the result confirmed an effectiveness of the proposed method. This research showed a practical method in which interaction of projection facade system can be used to user devices. The results of this study can be used as a base module for projection facade interaction system. In addition, It can be utilized for converged content development such as performances, games, education and various applications services.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.2
• /
• pp.287-294
• /
• 2017

Recently, many kinds of TV contents based on multimedia need transmission systems without the saved. In this study, we develop the streaming device and smart app to transmit and play without store for multimedia contents such a broadcasting, internet, VOD, video, and animation. To do this, we compare and analysis main CPU products, broadcasting tuners and interfaces for streaming sources, and memory products. We then design and implement the streaming device which supports 30fps@FHD H.264 decoding and streaming, and multimedia sources with more than three. We develop the software for these requirements. Thissystemis useful to support billing service for multimedia contents.

• The KIPS Transactions:PartD
• /
• v.15D no.6
• /
• pp.803-814
• /
• 2008

Product line architectures include variable parts to be selected according to product specific requirements. In order to derive architectures that are valid for a particular product from product line architectures, variabilities of product line architectures must be systematically managed. In this paper, we adopt an approach to variability management of product line architectures through an explicit mapping between a feature model and product line architecture models. If this mapping is incorrect or there exists inconsistency among product line architectural elements, variabilities of product line architectures cannot be managed correctly. Therefore, this paper formally defines product line architectural models in terms of conceptual, process, deployment, and module views, and mapping relationships between the feature model and the architectural models. Consistency rules for correct variability management of product line architectures are defined in terms of consistency in each of product line architecture model, consistency between different architectural view models, and consistency between a feature model and product line architectural models. These consistency rules provide a theoretical foundation for deriving valid product architecture from product line architectures.

• Elastomers and Composites
• /
• v.42 no.3
• /
• pp.151-158
• /
• 2007

MWNTs have been widely investigated due to unique properties of such as good electrical conductivity and thermal stability in polymer composites industries. This paper established the procedure to fabricate PMMA/MWNT composites by a modular intermeshing co-rotating twin screw extruder with L/D ratio of 42. The electrical properties of PMMA/MWNT composites with different content of MWNT have been investigated. A sheet resistance percolation was observed at 4 wt% of MWNT for the melt processed composites. Sheet resistance of PMMA/MWNT composite film containing 4 wt% of MWNT was nearby $10^4{\Omega}/sq$ and this shows the possibility of potential application to EMI (Electronic Magnetic Interference) shielding materials. The characteristics of composites were analyzed by TGA, DSC, and SEM. In addition, MFI (Melt Flow Index) has been measured to analyze the rheological property.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.6 s.360
• /
• pp.31-39
• /
• 2007

In this paper, a system for real-time or periodic measurement and analysis of RF parameters such as forward transmit power and pilot power in CDMA base station systems is proposed. Such RF characteristic parameter measurement can be prevented from system fault and used to achieve optimal service quality and maximum investment return through cell coverage expansion, subscriber capacity increase and so on. For forward power measurement, the local oscillator frequency for the detector is varied so that the transmit power for all channels can be measured. The channel power measurement can be used to analyze the variation in transmit power for changes in voice traffic. By comparing to forward $E_c/I_o$, the pilot channel power can be deducted, which can be used to determine uy degradation in transmit section modules such as the high dover amplifier. Since an accurate analysis of carefully measured data using the CDMA level detector must be made, the system is designed so that measurement errors due to changes in crest factor with modulation method can be overcome.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39C no.11
• /
• pp.1185-1191
• /
• 2014

An integrated ship area network has functionality of remote control and autonomous management of various sensors and instruments embedded or boarded in a ship. For such environment, a wireless bridge is essential to transmit control and/or managing information to sensors or instruments from a central integrated ship area network station. In this paper, one of reliable schemes of In-ship sensor networks using a Grid-based WPAN is proposed. The proposed scheme is based on a novel grid network which allows a multi-path communication, and is robust, energy efficient. The results demonstrate that the proposed Grid-based WPAN outperforms the IEEE 802.15.4 based network in terms of success ratio and power efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.4
• /
• pp.313-319
• /
• 2017

Fiber optics sensors that have been mainly applied to aerospace areas are now finding applicability in other areas, such as transportation, including railways. Among the sensors, the fiber Bragg grating (FBG) sensors have led to a steep increase due to their properties of absolute measurement and multiplexing capability. Generally, the FBG sensors adhere to structures and sensing modules using adhesives such as an epoxy. However, the measurement errors that occurred when the FBG sensors were used in a long-term application, where they were exposed to environmental thermal load, required calibration. For this reason, the thermal curing of adhesives needs to be investigated to enhance the reliability of the FBG sensor system. This can be done at room temperature through cyclic thermal load tests using four types of specimens. From the test results, it is confirmed that residual compressive strain occurs to the FBG sensors due to an initial cyclic thermal load. In conclusion, signals of the FBG sensors need to be stabilized for applying them to a long-term SHM.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.3B
• /
• pp.183-190
• /
• 2003

The explosion of the Internet has brought an acute need for efficient operation, which becomes to develop several technologies based on optical networks. By matching merging technology using wavelength multiplexing, an efficient administration with limited wavelength can provide scalability of network. The merging in optical layer has limitation of devices since the merging can not be performed in this layer. Hence the merging must be implemented in electronic layer. When the merging is implemented, the delay time would be increased in OXC (Optical Cross Connection), but the improvement of throughput rate will be expected in the process of explosive traffic due to reduction of optical channel supporting large bandwidth. In this thesis, we proposed an OXC of dual module having a merging function. We considered the optimum merging point with the largest in system performance and confirmed results using the simulation.