• Journal of the Korean Society of Systems Engineering
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• v.15 no.1
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• pp.9-15
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• 2019

DIRCM is a device that deception missiles by directing the light source to missile seeker with infra-red laser based turret. The effectiveness of the device is affected by changes of the turret's Field of View (FoV), and also influence of the interference devices determines the effect of the DIRCM's effectiveness. Therefore finding mounting location for DIRCM is critical parameter for the DIRCM's effectiveness. so we applied stiffness review, interference analysis, FoV analysis and simulation analysis method to Multi-purpose helicopter for the find DIRCM location. As a result, in case of 1 DIRCM mounted at helicopters bottom shows 30~40% survivability. case of 2 DIRCM mounted at both side shows 70~80% survivability.

• Journal of information and communication convergence engineering
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• v.20 no.2
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• pp.73-78
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• 2022

Based on experimental measurements conducted on many different practical wireless communication systems, ambient noise has been shown to be decidedly non-Gaussian owing to impulsive phenomena. However, most multiuser detection techniques proposed thus far have considered Gaussian noise only. They may therefore suffer from a considerable performance loss in the presence of impulsive ambient noise. In this paper, we consider a large-scale multiuser multiple-input multiple-output system in the presence of non-Gaussian noise and propose a genetic algorithm (GA) based detector for large-dimensional multiuser signal detection. The proposed algorithm is more robust than linear multi-user detectors for non-Gaussian noise because it uses a multi-directional search to manipulate and maintain a population of potential solutions. Meanwhile, the proposed GA-based algorithm has a comparable complexity because it does not require any complicated computations (e.g., a matrix inverse or derivation). The simulation results show that the GA offers a performance gain over the linear minimum mean square error algorithm for both non-Gaussian and Gaussian noise.

• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.37-46
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• 2010

In an IPTV system, the rights of the content and service provider can be protected by using Conditional Access System (CAS) and Digital Right Management (DRM). In case of the CAS, only the authorized user who has structured authentication keys can decrypt the encrypted content. However, since the CAS establishes a secure channel only between content provider and Smart Card (SC), it cannot protect the system against McCormac Hack attack which eavesdrops on unsecure channel between SC and Set-Top Box (STB) and SC cloning attack. In this paper, we propose a robust multi-STB assisted SC / STB authentication protocol which can protect the IPTV system against not only McCormac Hack attack, but also SC cloning attack. The previous works which bind a STB and a SC during the SC registration phase against the SC cloning attack does not support multi-STB environments. The proposed system which dynamically updates the STB information in subscriber management system using the bi-directional channel characteristic of IPTV system can support the user's multi-STB device effectively.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.215-220
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• 2005

Nowadays, various speech processing systems are being introduced in the fields of robotics. However, real-time processing and high performances are required to properly implement speech processing system for the autonomous robots. Achieving these goals requires advanced hardware techniques including intelligent software algorithms. For example, we need nonlinear amplifier boards which are able to adjust the compression radio (CR) via computer programming. And the necessity for noise reduction, double-buffering on EPLD (Erasable programmable logic device), simultaneous multi-channel AD conversion, distant sound localization will be explained in this paper. These ideas can be used to improve distant and omni-directional speech recognition. This speech processing system, based on embedded Linux system, is supposed to be mounted on the new home service robot, which is being developed at KIST (Korea Institute of Science and Technology)

• International Journal of Aeronautical and Space Sciences
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• v.2 no.2
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• pp.95-107
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• 2001

This paper is devoted to the parameter optimization of unmanned aerial vehicle's (UAV) flight control laws. Optimization procedure is based on the ideas of mixed $H_2/H_{\infty}$ control of multi-model plants. By using this approach, some partial $H_2$-terms defining the performance of nominal and parametrically perturbed Flight Control System (FCS) responses to deterministic command signals in stochastic atmosphere as well as $H_{\infty}$-terms defining robustness of the FCS can be incorporated in the composite cost function. Special penalty function imposed on the location of closed-loop system's poles keeps the speed of response and oscillatory properties for both nominal and perturbed FCS in reasonable limits. That is the reason why this procedure may provide reasonable trade-off between the performance and robustness of FCS that are very important especially for UAV. Its practical importance is illustrated by case studies of lateral and longitudinal control of small UAV.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1203-1208
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• 2010

Recently, there are environmental issues for sustainable transportation system to pursue the energy-efficient and environment-friendly public urban transit. These transportation system needs to offer demand-oriented high-quality service being on the same level with cab service for urban space. PRT(Personal Rapid Transit), small track-guided vehicle, is repeatedly mentioned as a possible alternative for the new urban public transportion system, but but there are not many researches on the operational optimal routing for PRT network. In this paper, the concept of PRT and general optimal routing methods are reviewed. And we suggest the optimal routing method for city-wide PRT network with multi-vehicles and stations, junctions and directional arcs. Futher research directions for PRT routing are presented.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.315-320
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• 2010

Recently, there are environmental issues for sustainable transportation system to pursue the energy-efficient and environment-friendly public urban transit. These transportation system needs to offer demand-oriented high-quality service being on the same level with cab service for urban space. PRT(Personal Rapid Transit), small track-guided vehicle, is repeatedly mentioned as a possible alternative for the new urban public transportion system, but but there are not many researches on the operational optimal routing for PRT network. In this paper, the concept of PRT and general optimal routing methods are reviewed. And we suggest the optimal routing method for city-wide PRT network with multi-vehicles and stations, junctions and directional arcs. Futher research directions for PRT routing are presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.402.1-402.1
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• 2014

Photonic force microscopy (PFM) is an optical tweezers-based scanning probe microscopy, which measures the forces in the range of fN to pN. The low stiffness leads proper to measure single molecular interaction. We introduce a novel photonic force microscopy to stably map various chemical properties as well as topographic information, utilizing weak molecular bond between probe and object's surface. First, we installed stable optical tweezers instrument, where an IR laser with 1064 nm wavelength was used as trapping source to reduce damage to biological sample. To manipulate trapped material, electric driven two-axis mirrors were used for x, y directional probe scanning and a piezo stage for z directional probe scanning. For resolution test, probe scans with vertical direction repeatedly at the same lateral position, where the vertical resolution is ~25 nm. To obtain the topography of surface which is etched glass, trapped bead scans 3-dimensionally and measures the contact position in each cycle. To acquire the chemical mapping, we design the DNA oligonucleotide pairs combining as a zipping structure, where one is attached at the surface of bead and other is arranged on surface. We measured the rupture force of molecular bonding to investigate chemical properties on the surface with various loading rate. We expect this system can realize a high-resolution multi-functional imaging technique able to acquire topographic map of objects and to distinguish difference of chemical properties between these objects simultaneously.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.911-918
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• 2008

In this paper, we propose new cell structures using multi-hop Relay Station(RS) based on IEEE802.16j in Narrow-Beam Trisector Cell (NBTC) and Wide-Beam Trisector Cell (WBTC), which are two methods for cell sectorization using 3-sector directional antennas. Then, we analyze our proposed structures compared with the existing system which does not use any RS about the numbers of optimized Base Station (BS) and multi-hop relay, the extended BS coverage, and the deployment cost according to the traffic density using optimization model. According to the results, we know the reduction of total deployment cost of the proposed systems and that WBTC is suitable when the traffic density is high and NBTC is suitable when the traffic density is low in our proposed multi-hop based NBTC and WBTC structures.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.3
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• pp.136-142
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• 2007

Recent researches in the recognition system have shown that SVM (Support Vector Machine) classifiers often have superior recognition rates in comparison to other classifiers. In this paper, we present the handwritten numeral recognition algorithm using SVM classifiers. The numeral features used in our algorithm are mesh features, directional features by Kirsch operators and concavity features, where first two features represent the foreground information of numerals and the last feature represents the background information of numerals. These features are complements each of the other. Since SVM is basically a binary classifier, it is required to construct and combine several binary SVMs to get the multi-class classifiers. We use two strategies for implementing multi-class SVM classifiers: "one against one" and "one against the rest", and examine their performances on the features used. The efficiency of our method is tested by the CENPARMI handwritten numeral database, and the recognition rate of 98.45% is achieved.