• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1069-1076
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• 2007

DOCSIS 3.0 protocol are proposed to support high-speed cable network DOCSIS 3.0 MAC protocol regulates CM and CMTS channel transfer times through MAP message. So MAP Inter-arrival time is primary factor of network performance. However, standards does not include the details of MAP Inter-arrival Time affecting the performance of MAC protocols for DOCSIS 3.0. In this paper, we evaluated the performance of DOCSIS 3.0 protocol follow in MAP Inter-arrival Time. Based on the evaluation results, we propose the optimal MAP Inter-arrival Time. We found that the protocol shows best performance when the MAP Inter-arrival Time is 0.05sec. The research results can apply to performance element which important for the construction of DOCSIS 3.0 base cable networks.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.277-281
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• 2013

Modern speaker verification systems based on support vector machines (SVMs) use Gaussian mixture model (GMM) supervectors as their input feature vectors, and the maximum a posteriori (MAP) adaptation is a conventional method for generating speaker-dependent GMMs by adapting a universal background model (UBM). MAP adaptation requires the appropriate amount of input utterance due to the number of model parameters to be estimated. On the other hand, with limited utterances, unreliable MAP adaptation can be performed, which causes adaptation noise even though the Bayesian priors used in the MAP adaptation smooth the movements between the UBM and speaker dependent GMMs. This paper proposes a sparse MAP adaptation method, which is known to perform well in the automatic speech recognition area. By introducing sparse MAP adaptation to the GMM-SVM-based speaker verification system, the adaptation noise can be mitigated effectively. The proposed method utilizes the L0 norm as a regularizer to induce sparsity. The experimental results on the TIMIT database showed that the sparse MAP-based GMM-SVM speaker verification system yields a 42.6% relative reduction in the equal error rate with few additional computations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.572-577
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• 1996

Stereolithography is a process used to rapidly produce stereolithographic parts directly from three dimensional CAD models. However, design methodologies necessary to create components to be built by stereolithography are different from those required by conventional machining processes. A case in point is the nescessity of support structures, which are used to support a component during the building the build but are removed once building and curing are complete. Support structures are required to anchor the component to the platform and to prevent sagging or disortion. This paper deals with the specially maintained SupportMap data structure to find some region which need support structures. Interferences between support structures and parts, as well as among support structures are checked and statically stable regions are searched to remove the surplus support structures. Cross shaped tooth profiles are designed for easy eliminating the support structures.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.108-114
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• 2015

Automated driving systems require a high level of performance regarding environmental perception, especially in urban environments. Today's on-board sensors such as radars or cameras do not reach a satisfying level of development from the point of view of robustness and availability. Thus, map data is often used as an additional data input to support these systems. An accurate digital map is used as a powerful additional sensor. In this paper, we propose a new approach for vehicle localization using a lane map and a single-layer LiDAR. The maps are created beforehand using a highly accurate DGPS and a single-layer LiDAR. A pose estimation of the vehicle was derived from an iterative closest point (ICP) match of LiDAR's intensity data to the lane map, and the estimated pose was used as an observation inside a Kalmanfilter framework. The achieved accuracy of the proposed localization algorithm is evaluated with a highly accurate DGPS to investigate the performance with respect to lateral vehicle control.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.16-21
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• 2006

Internet Engineering Task Force(IETF) proposed the Hierarchical Mobile IPv6(HMIPv6) to support mobility efficiently. The HMIPv6 was developed to reduce the signaling overhead and delay concerned with Binding Update in Mobile IPv6. However, the HMIPv6 still need a further enhancement for supporting the real-time application because HMIPv6 only concerns with the latency resulted within a MAP For providing seemless handoff we propose a scheme that can reduce latency when Mobile Node changes a MAP. Also we compare the HMIPv6 with the proposed scheme through a analysis model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.597-602
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• 2005

This paper proposes an efficient multicast scheme for the hierarchical mobile IPv6(HMIPv6). If a mobility anchor point(MAP) in a new domain does not support multicasting, an entering group member cannot join the multicast group through the new MAP The group member thus keeps receiving multicast packets from its home agent(HA) using Mobile IPv6 (MIPv6). This increases the propagation delay of binding update (BU) messages. However, our scheme enables an entering group member to keep receiving packets from the old multicast MAP. It can also reduce tunneling costs, total delivery costs and handover latency. We simulated the performance of our scheme by comparing it with the seamless multicast handover in a hierarchical mobile Pv6 (M-HMIPv6) using the delivery cost and handover latency factors.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.223-230
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• 2006

A MMORPG(Massively Multiplayer Online Role-Playing Game) is an online role-playing game in which a large number of players can interact with each other in the same world at the same time. Most of them require significant hardware requirements(e.g., servers and bandwidth), and dedicated support staff. Despite the efforts of developers, users often cite overpopulation, lag, and poor support as problems of games. In this paper, a dynamic load balancing method for MMORPGS is proposed. It tries to adapt to dynamic change of population by using dynamic map-partition method with VML(Virtual Map Layer) which consists of fields, sector groups, sectors, and cells. From the experimental results, our approach achieves about $23^{\sim}67%$ lower loads for each field server. By the modification to Virtual Area Layer, we can easily manage problems that come from changes of map data, resources' status, and users' behavior pattern.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1256-1262
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• 2008

In mobile broadcasting networks, handover is an important issue to support seamless mobility. DVB-H(Digital Video Broadcasting for Handheld) standard was developed to enhance mobile features for DVB-T(Digital Video Broadcasting -Terrestrial) standard. This paper proposes new approaches for improving handover performance in the DVB-H networks. The proposed handover schemes are targeted to two different DVB-H receivers: One is for the receivers equipped with GPS devices. The other is for ones without GPS support. The first handover approach modifies the cell description table (CDT) proposed in the literature [1]. The second proposes a novel estimation technique of predefined handover region based on a new handover map table (HMT). This new handover approach estimates a predefined handover region with the measured RSSI(Received Signal Strength Indication) signal patterns. Using proposed handover algorithm, we can reduce time and power consumption. Through the computer simulations, we evaluate the performance of handover algorithm.

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.20-26
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• 2007

A low-resolution national wind map, which is a prerequisite for setting up the national dissemination target and strategy of wind energy development, has been established by numerical wind simulation using the synoptic wind map, developed at the first stage, as an upper boundary condition. Based on the wind map, Wind Resource Information System has been composed in order to support scientific and systematic wind resource assessment and analysis.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.17-20
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• 2004

The purpose of this study is to arrange the digital maps of Hamamatsu City and to construct the map information system to support the prediction and restoration of Tokai earthquake disasters. The authors arrange the land condition map and compute the populations of each land surface conditions and revealed that $37\%$ of the whole population lives in the safe land, but $63\%$ lives in the rather unsafe surface condition. The authors also arrange the digital map of the main lines of water supply pipe lines in corporation with the Hamamatsu City Water Supply Department and revealed the rather dangerous pipe line area in case of Tokai earthquake.