• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.141-144
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• 2008

기존의 네트워크 환경에 이동성을 지원하기 위하여 Internet Engineering Task Force (IETF)에서는 Mobile IP(MIP)와 Mobile IPv6 (MIPv6)를 순차적으로 제안하였다. 그러나 MIP나 MIPv6는 유저가 요구하는 이동성을 지원하기에 많은 문제점을 나타내었고 이런 문제를 해결하기위해 Hierarchical MIPv6(HMIPv6)를 제안하였다. HMIPv6는 Home Agent (HA)를 향한 Binding Update (BU)를 줄이기 위해 Mobility Anchor Point (MAP) 라는 새로운 개념을 제안했다. 그러나 HMIPv6 역시 이동노드가 빠르게 이동하는 환경에서는 잦은 MAP BU로 인해 큰 오버헤드가 발생하는 문제점이 나타났다. 본 논문에서는 HMIPv6 환경에서 노드가 빠르게 이동할 때 발생하는 불필요한 MAP BU를 줄이기 위한 선택적 MAP 등록 기법을 제안한다. 이 기법은 기존에 제안되었던 계층적인 MAP 선택 기법들과는 다르게 상황에 따라 불필요한 MAP BU를 회피하는데서 차별성을 갖는다. 또한 OPNET을 이용한 시뮬레이션을 통해 기존의 HMIPv6에 비해 제안된 기법의 성능을 비교한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.535-537
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• 2000

자원을 예약하는 매커니즘은 IP를 기반으로 한 통합 서비스 네트워크(Integrated Service Network)에서 QoS(Quality of Service)를 지원하는데 필수적인 요소이다. 자원 예약 프로토콜인 RSVP는 수신자 지향의 자원 예약 프로토콜로, 이미 IETF(Internet Engineering Task Force)에 의해 표준으로 제정되었다. 하지만 RSVP는 고정된 네트워크를 위해 설계된 프로토콜이기 때문에 이동 환경에서 그대로 사용하기에는 적합하지 않다. 또한 이동 환경에서의 자원 예약 매커니즘에 대한 기존의 대부분의 연구들은 Mobile IPv4를 기반으로 수행되었기 때문에 IPv6를 기반으로 할 차세대 네트워크 환경에는 적합하지 않다. 따라서 본 논문에서는 기존 연구의 많은 문제점들을 해결하고 Mobile IPv6 기반 무선 네트워크에서 보다 효율적으로 QoS를 보장할 수 있는 새로운 프로토콜 모델을 제시한다.

• Journal of information and communication convergence engineering
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• v.22 no.1
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• pp.56-63
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• 2024

Despite the rapid strides in content-based image retrieval, a notable disparity persists between the visual features of images and the semantic features discerned by humans. Hence, image retrieval based on the association of semantic similarities recognized by humans with visual similarities is a difficult task for most image-retrieval systems. Our study endeavors to bridge this gap by refining image semantics, aligning them more closely with human perception. Deep learning techniques are used to semantically classify images and retrieve those that are semantically similar to personalized images. Moreover, we introduce a keyword-based image retrieval, enabling automatic labeling of images in mobile environments. The proposed approach can improve the performance of a mobile device with limited resources and bandwidth by performing retrieval based on the visual features and keywords of the image on the mobile device.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.6
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• pp.1620-1634
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• 2023

This paper studies the task of embedding nodes with multiple graphs representing multiple information channels, which is useful in a large volume of network clustering tasks. By learning a node using multiple graphs, various characteristics of the node can be represented and embedded stably. Existing studies using multi-channel networks have been conducted by integrating heterogeneous graphs or limiting common nodes appearing in multiple graphs to have similar embeddings. Although these methods effectively represent nodes, it also has limitations by assuming that all networks provide the same amount of information. This paper proposes a method to overcome these limitations; The proposed method gives different weights according to the source graph when embedding nodes; the characteristics of the graph with more important information can be reflected more in the node. To this end, a novel method incorporating a multi-channel gate layer is proposed to weigh more important channels and ignore unnecessary data to embed a node with multiple graphs. Empirical experiments demonstrate the effectiveness of the proposed multi-channel-based embedding methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1963-1978
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• 2015

With the advancement of mobile web environments, identification and analysis of the user behavior play a significant role and remains a challenging task to implement with variations observed in the model. This paper presents an efficient method for mining optimized user behavior prediction model using genetic algorithm on mobile web structure. The framework of optimized user behavior prediction model integrates the temporary and permanent register information and is stored immediately in the form of integrated logs which have higher precision and minimize the time for determining user behavior. Then by applying the temporal characteristics, suitable time interval table is obtained by segmenting the logs. The suitable time interval table that split the huge data logs is obtained using genetic algorithm. Existing cluster based temporal mobile sequential arrangement provide efficiency without bringing down the accuracy but compromise precision during the prediction of user behavior. To efficiently discover the mobile users' behavior, prediction model is associated with region and requested services, a method called optimized user behavior Prediction Model using Genetic Algorithm (PM-GA) on mobile web structure is introduced. This paper also provides a technique called MAA during the increase in the number of models related to the region and requested services are observed. Based on our analysis, we content that PM-GA provides improved performance in terms of precision, number of mobile models generated, execution time and increasing the prediction accuracy. Experiments are conducted with different parameter on real dataset in mobile web environment. Analytical and empirical result offers an efficient and effective mining and prediction of user behavior prediction model on mobile web structure.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1887-1891
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• 2005

Despite significant advances in multimedia transferring technologies in various fields of robotics, it is sometimes quite difficult for the operator to fully understand the context of 3D remote environments from 2D image feedback. Particularly, in the remote control of mobile robots, the recognition of the object associated with the task is very important, because the operator has to control the robot safely in various situations not through trial and error. Therefore, it is necessary to provide the operator with 3D volumetric models of the object and object-related information as well such as locations, shape, size, material properties, and so on. Thus, in this paper, we propose a vision-based human interface system that provides an interactive, information-rich map through network-based information brokering. The system consists of an object recognition part, a 3D map building part, a networked knowledge base part, and a control part of the mobile robot.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.35-43
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• 2006

In this paper we have presented a network based high-speed handover protocol using NetLMM(Network based Localized Mobility Management) WG protocol in IETF(Internet Engineering Task Force). We use IEEE 802.21 MIHS(Media Independent Handover Services) for improving handover latency and we analysis proposed Fast NetLMM protocol performance using Fluid Flow Mobility Model. Evaluation results show that the Fast NetLMM protocol performance is better than other mobility management protocols.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.17-17
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• 1996

An experimental research is a useful approach for realizing autonomous mobile robots to work in real environment. We are developing an autonomous mobile robot platform named "Yamabico" as a tool for experimental real world robotics research. The architecture of Yamabico is based on the concept of centralized decision making and functionally modularization. Yamabico robot has two level structure with behavior and function levels, and its hardware and software are functionally distributed for providing incremental development and good maintenancibility. We are using many Yamabico robots in our laboratory to realize the robust navigation technology for autonomous robots. The methodology for experimental and task-oriented approach of mobile robotics will be presented. And some experimental results of real world navigation in indoor and outdoor environment will be shown. be shown.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.395-399
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• 2006

A method to recognize unpaved road region using a 3D depth measurement system is proposed for mobile robots. For autonomous maneuvering of mobile robots, recognition of obstacles or recognition of road region is the essential task. In this paper, the 3D depth measurement system which is composed of a rotating mirror, a line laser and mono-camera is employed to detect depth, where the laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The obtained depth information is converted into an image. Such depth images of the road region represent even and plane while that of off-road region is irregular or textured. Therefore, the problem falls into a texture identification problem. Road region is detected employing a simple spatial differentiation technique to detect the plain textured area. Identification results of the diverse situation of unpaved trail are included in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.818-829
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• 2003

A cooperating control algorithm for two nonholonomic mobile robots is proposed. The task is composed of collision avoidance against obstacles and carrying a ladder. The front robot and the rear robot are called the leader and the follower, respectively. Each robot has a nonholonomic constraint so it cannot move in perpendicular directions. The environment is initially supposed to be unknown except target position. The torque that drives leader is determined by distance between the leader and the target position or the distance between it and the obstacles. The torque by target is attractive and the torque by obstacles is repulsive. The two mobile robots are supposed to be connected by link that can be expanded and contracted. The follower computes its torque using position and orientation information from the leader by communication. Simulation results show that the robots can drive to target position without colliding into the obstacles and maintain the distance in the allowable range.