• Journal of Ubiquitous Convergence Technology
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• v.2 no.1
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• pp.1-11
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• 2008

An effective solution to the problems caused by the explosive growth of World Wide Web is a web caching that employing an additional server, called proxy cache, between the clients and main server for caching the popular web objects near the clients. However, a single proxy cache can easily become the bottleneck. Deploying groups of cooperative caches provides scalability and robustness by eliminating the limitations caused by a single proxy cache. Two common architectures to implement the cooperative caching are hierarchical and distributed caching systems. Unfortunately, both architectures suffer from performance limitations. We propose an efficient hybrid caching architecture eliminating these limitations by using both the hierarchical and same level caches. Our performance evaluation with our investigated simulator shows that the proposed architecture offers the best of both existing architectures in terms of cache hit rate, the number of query messages from clients, and response time.

• ETRI Journal
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• v.35 no.4
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• pp.666-676
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• 2013

With the recent growth in smartphone services, the "mobile" environment has become a key factor to consider in the design of the future Internet. In this paper, we propose Mobile-Oriented Future Internet (MOFI), which is a new architecture for the future Internet for mobile-oriented environments. The MOFI architecture is designed with three functional features: global identifier and local locator in the identifier-locator separation, query-first data delivery for route optimization, and distributed control of identifier-locator mapping. The proposed architecture and functional operations are implemented and tested using the Linux platform. From the experiment results, we see that the MOFI architecture performs better than the existing identifier-locator separation schemes, such as Proxy Mobile IP and Host Identity Protocol, in terms of data throughout, mapping control overhead, and handover delay.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.577-594
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• 2020

Service Function Chaining (SFC) supports services through linking an ordered list of functions. There may be multiple instances of the same function, which provides a challenge to select available instances for all the functions in an SFC and generate a specific Service Function Path (SFP). Aiming to solve the problem of SFP selection, we propose an architecture consisting of distributed SFP algorithm and central control mechanism. Nodes generate distributed routings based on the first function and destination node in each service request. Controller supervises all of the distributed routing tables and modifies paths as required. The architecture is scalable, robust and quickly reacts to failures because of distributed routings. Besides, it enables centralized and direct control of the forwarding behavior with the help of central control mechanism. Simulation results show that distributed routing tables can generate efficient SFP and the average cost is acceptable. Compared with other algorithms, our design has a good performance on average cost of paths and load balancing, and the response delay to service requests is much lower.

• Journal of Information Processing Systems
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• v.13 no.1
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• pp.184-195
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• 2017

In recent decades, the ad hoc network for vehicles has been a core network technology to provide comfort and security to drivers in vehicle environments. However, emerging applications and services require major changes in underlying network models and computing that require new road network planning. Meanwhile, blockchain widely known as one of the disruptive technologies has emerged in recent years, is experiencing rapid development and has the potential to revolutionize intelligent transport systems. Blockchain can be used to build an intelligent, secure, distributed and autonomous transport system. It allows better utilization of the infrastructure and resources of intelligent transport systems, particularly effective for crowdsourcing technology. In this paper, we proposes a vehicle network architecture based on blockchain in the smart city (Block-VN). Block-VN is a reliable and secure architecture that operates in a distributed way to build the new distributed transport management system. We are considering a new network system of vehicles, Block-VN, above them. In addition, we examine how the network of vehicles evolves with paradigms focused on networking and vehicular information. Finally, we discuss service scenarios and design principles for Block-VN.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.694-701
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• 2013

This paper deals with the problem of accurately tracking a single target moving through UWSNs (Underwater Wireless Sensor Networks) by employing underwater acoustic sensors. This paper addresses the issues of estimating the states of the target, and improving energy efficiency by applying a Kalman filter in a distributed architecture. Each underwater wireless sensor nodes composing the UWSNs is battery-powered, so the energy conservation problem is a critical issue. This paper provides an algorithm which increases the energy efficiency of each sensor node through WuS (Waked-up/Sleeping) and VM (Valid Measurement) selecting schemes. Simulation results illustrate the performance of the distributed tracking filter.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.343-350
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• 1999

This study introduce how distributed object technology can be applied effectively to use in a integrated structural design systems environment with the rapid increasement in the use of network technology. The architecture and management models of the developed systems are described by the CORBA(Com mon Object Request Broke Architecture) distribution standard and objects in Java language. The proposed system can be used for communicating with data between remote designers, regardless of the H/W or S/W platforms they use. Introduction of distributed objects methodologies to a Integrated structural design systems provide advanced levels of integration in structural design environment.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.532-539
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• 2001

In robot teleoperation, much research has been carried out to control the slave robot from remote site. One of the essential devices for robot teleoperation is the masterarm, which is a path command generating device worn on human arm. In this paper, a new masterarm based on human kinematics is proposed. Its controller is based on the distributed controller architecture composed of two controller parts: a host controller and a set of satellite controllers. Each satellite controller measures the corresponding joint angle, while the host controller performs forward and inverse kinematics calculation. This distributed controller architecture can make the data updating faster, which allows to implement real-time implementation. The host controller and the satellited controllers are networked via three-wire daisy-chained SPI(Serial Peripheral Interface) protocol, so this architecture makes the electrical wiring very simple, and enhances maintenance. Analytical method for finding three additional unknown joint angles is derived using only three measured angles for each shoulder and wrist, which makes th hardware implementation very simple by minimizing the required number of satellite controllers. Finally, the simulation and experiment results are given to demonstrate the usefulness and performance of the proposed masterarm.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.678-681
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• 2002

In this paper, we propose a block LMS algorithm using distributed arithmetic (BDA) and a multi-memory block structured BDA (MBDA). Moreover, we propose an effective VLSI architecture of adaptive digital filter using MBDA, and evaluate the sampling rate and output latency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.703-706
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• 2001

This paper presents a component-based integration framework and its software component architecture for supporting the rapid integration of legacy design supporting systems in the distributed environment. Also, using standard interface, this software component architecture provides flexibility, extensibility and compatibility which ensure software components to be independent of the integration middleware and systems to be integrated.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.295-297
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• 2005

This paper uses our proposed model for connecting ubiquitous physical objects over the web using URI, while utilizing the already developed frameworks, for ubiquitous service discovery like JINI, UPnP, and RDF/OWL for semantic web. By using this proposed scheme, we have presented architecture of a service oriented modular distributed ubiquitous middleware i.e. MDMA