• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1164-1170
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• 2002

In the ACE2000 MPLS system, MPLS Interface Module(MIM) is composed of an ATM Interface Module and a HFMA performing a packet forwarding. In the MIM, the HFMA RSAR receive cells from the Physical layer and reassemble the cells. And the IP Lookup controller perform a packet forwarding after packet classification. Forwarded packet is segmented into cells in the HFMA TSAR and transfer to the ALMA for the transmission to an ATM cell switch. When the MIM make use of an ATM Interface Module, it directly connect the ALMA with a PHY layer using the UTOPIA Level2 interface. Then, an ALMA performs Master Mode. Also, the HFMA TSAR performs the Master Mode in the MIM. Therefore, the UTOPIA-L2 Controller of the Slave Mode require for interfacing between an ALMA and a HFHA TSAR. In this paper, we implement the architecture and cell control mechanism for the UTOPIA-L2 Controller supporting Multi-ports.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.355-368
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• 2006

This paper introduces a new split-TCP approach for improving TCP performance over IEEE 802.11-based wireless LANs. TCP over wireless LANs differently from wired networks is not aggressive, which is a fundamental reason for poor performance. Therefore, we propose TAS (TCP-Aware Sub-layer) to migigate this problem. Our scheme extends the split-connection approach that divides a connection into two different connections at a split point such as an access point (AP). Using TAS, a wireless node emulates TCP ACK packets using MAC ACK frames, instead of receiving real TCP ACK packets. We compared TAS with both normal TCP and I-TCP (Indirect TCP) by NS2 simulation. Results show that TAS achieves higher throughput, more fair resource allocation and, in power-saving mode, shorter delays.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.188-194
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• 2007

We propose a new ad hoc multicast routing protocol for based on the ontology scheme called inference network. Ontology knowledge-based is one of the structure of context-aware. We will have developed an algorithm that will design multi-hierarchy Layered networks to simulate a desired system.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.304-312
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• 2010

This paper presents the design of alert message and message segmentation method for the Terrestrial DMB Automatic Emergency Alert Service Standard. This paper begins with the introduction of the standard and some background. The alert message contains the essential information of the alert. Structured information is represented as coded fields and the unstructured as short sentences. Design factors of each field are analyzed first. Next each field’s semantics and syntax are described. The message segmentation method is presented next. The previous study selected FIDC as the message delivery channel. However, in most cases, the size of the alert message exceeds the maximum size of FIG, which is the basic unit packet for the channel. The current T-DMB standard does not support the segmentation method for FIDC. To solve the problem, this paper proposes an elegant segmentation method that garantees reliable, flexible, and fast receiver characteristic. This paper concludes with some additional tasks that should be resolved before the full-time alert service.

• Journal of Broadcast Engineering
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• v.18 no.6
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• pp.884-894
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• 2013

In this paper, we investigate the characteristics of power amplifiers and simplified memoryless non-linear power amplifier models for energy efficient communication system. First, we present the transfer function of GaAs FET (Gallium Arsenide Field Effect Transistor) that is widely used for high power amplifier. From those investigations, we introduce the instantaneous efficiencies and methods of amplification by assuming that the saturated current is constant, while perfect linearity is exploited under knee voltage. Then, we discuss four non-linear power amplifier models in a baseband signal processing. Finally, we explain the specified total power consumption model in a base station to achieve the resonable analysis for energy efficient communication.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.4
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• pp.191-197
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• 2005

Biped walking is the main feature of a humanoid robot. In a biped walking robot, there are many actuators to be controlled and many sensors to be interfaced. In this paper, we propose a DSP-based controller for a miniature biped walking robot with 21 RC servo motors. The proposed controller has a hierarchical structure; a host PC, a DSP-based main controller, and an auxiliary controller with an FPGA chip. The host PC generates and transmits the robot walking data for given walking parameters such as stride, walking period, etc. The main controller implemented with a TMS320LF2407A controls 21 RC servo motors via the auxiliary controller. We also perform some experiments for balancing motion and walking on a slope terrain with interfacing a 2-axis acceleration sensor and a TMS320LF2407A.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1607-1617
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• 2010

In this paper we propose MA-CBRP, mesh adaptive algorithm for wireless mesh networks. MA-CBRP is a hybrid algorithm based on ad-hoc CBRP protocol. In MA-CBRP, the mesh router periodically sends the ANN message as like Hello-message in CBRP. ANN message allows to all clients periodically store a route towards the mesh-router and renewal information in their routing cache. While CBRP periodically reply Hello-message, MA-CBRP does not reply to achieve less overhead. After receiving ANN message, mesh client send JOIN message to mesh router when the route towards mesh router changed. at the same time Register the entry to mesh router, it can achieve to reduce overhead of control the route and shorten the time to find route. consequently, MA-CBRP shows 7% reduced overhead and shortened time to find route than CBRP with regardless of clients number.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.81-87
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• 2020

In this paper, proposes a health status monitoring system for socially marginalized elderly households living alone. This system is implemented by collecting various PHR biometric signals and residential environment information through IoT devices. In addition, the company aims to establish a basic infrastructure that can understand the situation of lonely deaths and implement prevention programs by strengthening the predictive ability through data analysis of the DB server based on PHR and information collected from IoT sensors. The sensor consists of an environmental information collection sensor and a noncontact and wearable sensor for biometric signal collection. A gateway is required to transmit the collected data to the server, and the prototype is presented in this paper. The paper has a discussion purpose of policy task for expanding medical welfare service. The results of this study are believed to help expand services to the socially marginalized and improve the medical environment of the people.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.141-150
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• 2008

In this mobile computing environment, data broadcasting is widely used to resolve the problem of limited power and bandwidth of mobile equipments. Most previous broadcast indexing methods concentrate on flat data. However. with the growing popularity of XML, an increasing amount of information is being stored and exchanged in the XML format. We propose a novel indexing method. called TOP tree(Tree Ordering based Path summary tree), for indexing XML document on mobile broadcast environments. TOP tree is a path summary tree which provides a concise structure summary at group level using global IDs and element information at local level using local IDs. Based on the TOP tree representation, we suggest a broadcast stream generation and query Processing method that efficiently handles not only simple Path queries but also multiple path queries. We have compared our indexing method with other indexing methods. Evaluation results show that our approaches can effectively improve the access time and tune-in time in a wireless broadcasting environment.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.105-113
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• 2008

While the wireless sensor network has a strong point which does not have effect on whole activities of network even though neighboring sensor nods fail activities of some sensor nod or make some functions disappear by the characteristic of similar information detection, it has problems which is slowing down of wireless medium, transfer character with severe error, limited power supply, the impossibility of change by optional arrangement of sensor nods etc. This paper proposes PRML techniques which performs the fittest course searching process to reduce power consumption of entire nods while guarantees the scalability of network organizing sensor nods hierarchically. The proposed technique can scatter the load of cluster head by considering the connectivity with surplus energy of nod and reduce the frequency of communication among the nods. As a result of the analysis in comparison with LEACH-C and HEED technique, PRML technique get efficiency of average 6.4% in energy consuming respect of cluster head, efficiency of average 8% in entire energy consuming respect, and more efficiency of average 7.5% in other energy consuming distribution of network scalability than LEACH-C and HEED technique.