• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.32-40
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• 2001

In this paper, we propose a high-speed modular multiplication algorithm which revises conventional Montgomery's algorithm. A hardware architecture is also presented to implement 1024-bit RSA cryptosystem for digital signature based on the proposed algorithm. Each iteration in our approach requires only one addition operation for two n-bit integers, while that in Montgomery's requires two addition operations for three n-bit integers. The system which is modelled in VHDL(VHSIC Hardware Description Language) is simulated in functionally through the use of $Synopsys^{TM}$ tools on a Axil-320 workstation, where Altera 10K libraries are used for logic synthesis. For FPGA implementation, timing simulation is also performed through the use of Altera MAX + PLUS II. Experimental results show that the proposed RSA cryptosystem has distinctive features that not only computation speed is faster but also hardware area is drastically reduced compared to conventional approach.

• Journal of KIISE:Information Networking
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• v.41 no.4
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• pp.167-176
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• 2014

In this paper, we discuss the implementation and experimentations of a new future Internet architecture for mobile-oriented environments, named Mobile Oriented Future Internet (MOFI). The MOFI architecture is featured by the host identifier and local locator for identifier-locator separation, Query-First Data Delivery (QFDD), and Distributed Mapping System (DMS) for identifier-locator mapping control. In the existing study on MOFI, we examined the intra-domain mobility control, the implementation of MOFI over Linux platform, and the performance analysis over the small-scale testbed. In this paper, we describe how to implement the MOFI architecture for inter-domain mobility control by using the OpenFlow and Click Modular Router platform. From the experimentations over the KOREN testbed, we can see that the MOFI scheme can give better performance than the existing Proxy Mobile IP scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.115-121
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• 2006

The efficiency of the multiplier largely depends on the representation of finite filed elements such as normal basis, polynomial basis, dual basis, and redundant representation, and so on. In particular, the redundant representation is attractive since it can simply implement squaring and modular reduction. In this paper, we propose an efficient bit-parallel multiplier for GF(2m) defined by an irreducible all-one polynomial using a redundant representation. We modify the well-known multiplication method which was proposed by Karatsuba to improve the efficiency of the proposed bit-parallel multiplier. As a result, the proposed multiplier has a lower space complexity compared to the previously known multipliers using all-one polynomials. On the other hand, its time complexity is similar to the previously proposed ones.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.139-146
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• 2002

The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent's dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to choose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input-output pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless these algorithms can learn the optimal policy if the agent can visit every state-action pair infinitely. However, the biggest problem of monolithic reinforcement learning is that its straightforward applications do not successfully scale up to more complex environments due to the intractable large space of states. In order to address this problem, we suggest Adaptive Mediation-based Modular Q-Learning (AMMQL) as an improvement of the existing Modular Q-Learning (MQL). While simple modular Q-learning combines the results from each learning module in a fixed way, AMMQL combines them in a more flexible way by assigning different weight to each module according to its contribution to rewards. Therefore in addition to resolving the problem of large state space effectively, AMMQL can show higher adaptability to environmental changes than pure MQL. In this paper we use the AMMQL algorithn as a learning method for dynamic positioning of the robot soccer agent, and implement a robot soccer agent system called Cogitoniks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.17-23
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• 2020

This paper proposes a simulation model using an equivalent circuit for the development of an MMC system. The MMC has been chosen as the most suitable topology for high voltage power transmission, such as a voltage-type HVDC, and it has dozens to hundreds of sub-modules in the form of a half-bridge or full-bridge connected in series. A simulation study is essential for the development of an MMC algorithm. On the other hand, it is virtually impossible to construct and implement MMC simulation models, including hundreds or thousands of switching devices. Therefore, this paper presents an MMC equivalent model, which is easily expandable and implemented by modeling the dynamic characteristics. The voltage and current equation of the equivalent circuit was calculated using the direction of the arm current and switching signal. The model was implemented on Matlab/Simulink. In this paper, to show the validity of the model developed using Matlab/Simulink, the simulation results of a five-level MMC using the real switching element and the proposed equivalent model are shown. The validity of the proposed model was verified by showing that the current and voltage waveform in the two models match each other.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.534-546
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• 2009

Query by humming is an effective and intuitive querying mechanism when a user wants to find a song without knowing lyrics. The query by humming system takes a user-hummed melody as input, compares it with melodies in a music database, and returns top-k similar melodies to the input. In this paper, we propose a novel algebra for query by humming, and design and implement a real query by humming system called HummingBase by exploiting the algebra. By analyzing existing similarity search techniques, we derive 10 core operators for the algebra. By using the well-defined algebra, we can easily implement such a system in a extensible and modular way. With two case studies, we show that the proposed algebra can easily represent the query processing processes of existing query-by-humming systems.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.411-420
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• 2005

World leading company and research centers have invested much cost and effort into a PLM and digital manufacturing field to obtain their own competitiveness. We have been trying to apply a digital manufacturing, especially simulation to ship production process as a part of PLM implementation for a shipyard. A shipbuilding production system and processes have a complexity and a peculiarity different from other kinds of production systems. So, new analysis and modeling methodology is required to implement digital shipyard. which is a digital manufacturing system for a shipbuilding company. This paper suggests an analysis and simulation modeling methodologies for an implementation of a digital shipyard. New methodologies such as a database-merged simulation, a distributed simulation, a modular simulation with a model library and a 3-tire simulation framework are developed.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.249-255
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• 2002

Since the stationary alignment process of the SDINS is not completely observable, some furls of the aided alignment have been applied. The purpose of this paper is to propose a new initial alignment algorithm, which utilizes the attitude output from the AGPS(Attitude Determination GPS) receiver and to demonstrate the feasibility of the proposed algorithm with several experimental results. A Kalman filter is designed for utilizing the attitude output as well as the zero velocity information. Also analyzed is the observability of the SDINS error model. To show the feasibility of the proposed scheme, we implement an alignment system where HG1700AE IMU (Inertial Measurement Unit) from Honeywell and an AGPS receiver designed at Chungnam National University are used. Test trials are done to evaluate the performance of the proposed alignment scheme. The proposed algorithm provides as good initial alignment performance as a high accurate navigation system, MAPS(Modular Azimuth Positioning System) INS.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.3
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• pp.157-163
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• 2014

This paper demonstrates the benefit of using MOOS-IvP in the development of control system for Unmanned Underwater Vehicles(UUV). The demand for autonomy in UUVs has significantly increased due to the complexity in missions to be performed. Furthermore, the increased number of sensors and actuators that are interconnected through a network has introduced a need for a middleware platform for UUVs. In this context, MOOS-IvP, which is an open source software architecture, has been developed by several researchers from MIT, Oxford University, and NUWC. The MOOS software is a communication middleware based on the publish-subscribe architecture allowing each application to communicate through a MOOS database. The IvP Helm, which is one of the MOOS modules, publishes vehicle commands using multi-objective optimization in order to implement autonomous decision making. This paper explores the benefit of MOOS-IvP in the development of control software for UUVs by using a case study with an auto depth control system based on self-organizing fuzzy logic control. The simulation results show that the design and verification of UUV control software based on MOOS-IvP can be carried out quickly and efficiently thanks to the reuse of source codes, modular-based architecture, and the high level of scalability.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.41-47
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• 2013

In this paper, for this open system-based virtual resource monitoring system was designed. Virtual resources, CPU, memory, disk, network, each subdivided into parts, each modular implementation. Implementation results in real time CPU, memory, disk, network information, confirmed the results of monitoring. System designed to implement the Windows, Linux, Xen was used for the operating system, implementation language, C++ was used, the structure of the system, such as the ability to upgrade and add scalability and modularity by taking into account the features available in cloud computing environments applicable to cloud computing, virtual resource monitoring system has been implemented.