• Current Optics and Photonics
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• 제5권6호
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• pp.641-651
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• 2021

To handle the servo delay in a real-time adaptive optics system, a linear subspace system identification algorithm was employed to model the system, and the accuracy of the system identification was verified by numerical calculation. Experimental verification was conducted in a real test bed system. Through analysis and comparison of the experimental results, the convergence can be achieved only 200 times with prediction and 300 times without prediction. After the wavefront peak-to-valley value converges, its mean values are 0.27, 4.27, and 10.14 ㎛ when the communication distances are 1.2, 4.5, and 10.2 km, respectively. The prediction algorithm can effectively improve the convergence speed of the peak-to-valley value and improve the free-space optical communication performance.

• 소성∙가공
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• 제19권3호
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• pp.185-190
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• 2010

Application of CAE analyses are wide spread in shaping processes and structural safety verification of plastic products. The importance of CAE analysis and its contributions are getting increase since the processibility and structural safety of product can be predicted. CAE analysis for complex shaped product need a lot of time for modeling and computation compare with simpler one. Therefore careful simulation modeling is required for complex shaped product. Structural analysis for plastic door handle of automobile has been performed and structural safety has been investigated for various load directions and modeling cases. Large stress occurred at the hinge in handle regardless of load direction and modeling case. Consequently hinge is considered structurally very weak among the parts in plastic door handle. It is concluded that simple modeling rather than total modeling with adequate boundary condition equivalent to real situation gives reasonable computational results with saving modeling effort and computation time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1074-1079
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• 2007

We will introduce speech/speaker recognition algorithm for the isolated word. In general case of speaker verification, Gaussian Mixture Model (GMM) is used to model the feature vectors of reference speech signals. On the other hand, Dynamic Time Warping (DTW) based template matching technique was proposed for the isolated word recognition in several years ago. We combine these two different concepts in a single method and then implement in a real time speaker/speech recognition system. Using our proposed method, it is guaranteed that a small number of reference speeches (5 or 6 times training) are enough to make reference model to satisfy 90% of recognition performance.

• Journal of information and communication convergence engineering
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• 제20권4호
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• pp.273-279
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• 2022

Owing to the need to establish a cooperative-intelligent transport system (C-ITS) environment in the transportation sector locally and abroad, various research and development efforts such as high-tech road infrastructure, connection technology between road components, and traffic information systems are currently underway. However, the current central control center-oriented information collection and provision service structure and the insufficient road infrastructure limit the realization of the C-ITS, which requires a diversity of traffic information, real-time data, advanced traffic safety management, and transportation convenience services. In this study, a network construction method based on the existing received signal strength indicator (RSSI) selected as a comparison target, and the experimental target and the proposed intelligent edge network compared and analyzed. The result of the analysis showed that the data transmission rate in the intelligent edge network was 97.48%, the data transmission time was 215 ms, and the recovery time of network failure was 49,983 ms.

• 자동차안전학회지
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• 제15권2호
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• pp.42-48
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• 2023

In recent years, automated vehicles have garnered attention in the multidisciplinary research field, promising increased safety on the road and new opportunities for passengers. High-Definition (HD) maps have been in development for many years as they offer roadmaps with inch-perfect accuracy and high environmental fidelity, containing precise information about pedestrian crossings, traffic lights/signs, barriers, and more. Demonstrating autonomous driving requires verification of driving on actual roads, but this can be challenging, time-consuming, and costly. To overcome these obstacles, creating HD maps of real roads in a simulation and conducting virtual driving has become an alternative solution. However, existing HD maps using high-precision data are expensive and time-consuming to build, which limits their verification in various environments and on different roads. Thus, it is challenging to demonstrate autonomous driving on anything other than extremely limited roads and environments. In this paper, we propose a new and simple method for implementing HD maps that are more accessible for autonomous driving demonstrations. Our HD map combines the CARLA simulator and OpenStreetMap (OSM) data, which are both open-source, allowing for the creation of HD maps containing high-accuracy road information globally with minimal dependence. Our results show that our easily accessible HD map has an accuracy of 98.28% for longitudinal length on straight roads and 98.42% on curved roads. Moreover, the accuracy for the lateral direction for the road width represented 100% compared to the manual method reflected with the exact road data. The proposed method can contribute to the advancement of autonomous driving and enable its demonstration in diverse environments and on various roads.

• Agribusiness and Information Management
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• 제6권2호
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• pp.32-39
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• 2014

The goal of this research was to develop a portable system that could be used to evaluate the quality of milk in real time at a raw milk production site. A real-time portable quality evaluation system for raw milk was developed to enable non-destructive quality evaluation of somatic cell count (SCC), fat, protein, lactose, and total solid (TS) in milk samples. A prediction model of SCC, fat, protein, lactose, and TS was constructed using partial least squares (PLS) and 200 milk samples were used to evaluate the prediction performance of the portable quality evaluation system and high performance spectroscopy. Through prediction model development and verification, it was found that the accuracy of high performance spectroscopy was 90% for SSC, 96% for fat, 96% for protein, 91% for lactose, and 97% for TS. In comparison, the accuracy of the portable quality evaluation system was relatively low, at 90% for SSC, 95% for fat, 92% for protein, 89% for lactose, 92% for TS. However, the measurement time for high performance spectroscopy was 10 minutes for 1 sample, while for the portable quality evaluation system it was 6 minutes. This means that the high performance spectroscopy system can measure 48 samples per day (8 hours), while the portable quality evaluation system can measure 80 (8 hours). Therefore, it was found that the portable quality evaluation system enables quick on-site quality evaluation of milk samples.

• 한국정보통신학회논문지
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• 제21권9호
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• pp.1718-1724
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• 2017

최근 IoT기반으로 가전제품을 실시간 모니터링을 하는 스마트 플러그가 활성화 되고 있다. 이를 통해 상시 실시간 에너지 소비 모니터링을 통한 소비자의 에너지 절약 유도를 하고, 소비자 설정 기반의 알람 기능을 통해 소비전력을 절감하는 효과를 보고 있다. 본 논문에서는 이러한 실시간 모니터링을 위해 벽 전원 콘센트에서 나오는 교류 전류를 측정한다. 이때, 가전제품마다의 전류 패턴을 분류하고 어떤 제품이 동작하는지 판단을 위해 딥러닝(Deep learning)으로 실험하였다. 전류 패턴의 학습으로 제품의 종류에 따른 인식 성능을 검증하기 위하여, 교차 검증 방법과 붓스트랩(Bootstrap) 검증 방법을 이용하였다. 또한 Cost function과 학습 성공률(Accuracy)이 Train 데이터와 Test 데이터가 동일함을 확인하였다.

• 한국항행학회논문지
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• 제5권1호
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• pp.1-10
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• 2001

음성은 차량 운행시 여러 가지 조작으로 분주한 운전자에게 간편한 장비 입력 및 조작을 위한 수단으로 유용한 특성을 지니고 있다. 본 논문에서는 이런 음성의 특성을 이용하여 차량 도난이나 중요한 온라인 서비스 접근시 신원을 증명할 수 있는 화자증명 방식을 제안한다. 이 방식에서는 음성의 언어정보를 이용하는 지속음 인식 기법과 함께 확률적 인식 방식에 비해 몇 가지 이점을 갖는 MLP(multi-layer perceptron)를 사용한다. 하지만 MLP를 사용하는 인식 기법은 학습에 많은 계산량을 요구하므로 실시간으로 화자를 등록해야 하는 화자증명에서는 적용하기가 쉽지 않다. 이 문제를 해결하기 위해 본 논문에서는 기존의 화자점수 평준화 방법에서 화자군집 모델 기법을 도입하여 배경화자를 사전에 여러 개의 작은 화자군집으로 분리하는 방법을 제안한다. 등록화자를 이렇게 나눈 화자군집 중 하나로 분류한 뒤 해당 화자군집에 대해서만 등록 학습과정을 거치는 방법으로 계산량을 큰 폭으로 줄일 수 있다.

• 한국항공우주학회지
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• 제37권7호
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• pp.701-708
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• 2009

개발된 비행제어컴퓨터(DFLCC: Developed Flight Control Computer)의 비행제어법칙은 고등훈련기급 항공기의 시제 최종 형상의 비행제어소프트웨어(OFP: Operation Flight Program)를 기반으로 개발되었다. 비행제어법칙은 상용 개발 툴을 이용하여 GUI(Graphic User Interface) 환경에서 설계되며, C 코드로 변환되어 OFP 에 반영된다. 그리고 OFP는 정형화된 검증절차를 통하여 검증되는데, 검증과정을 거치기 전에 비실시간 환경에서 C코드로 변환된 비행제어법칙과 기반이 되는 비행제어법칙의 상사성(similarity)을 검증하고, 구성된 HILS(Hardware In-the-Loop Simulator) 환경의 신뢰성(reliability)을 사전에 검증하는 절차가 필요하다. 비행제어법칙의 상사성은 비실시간 환경에서 고등훈련기급 항공기의 시제 최종 버전의 비행제어법칙과 개발된 비행제어법칙의 응답특성을 상호 비교하여 검증된다. 또한, 구성된 HILS 환경의 신뢰성은 비실시간 시뮬레이션 툴을 기반으로 HILS 결과와 항공기 응답특성을 비교하여 검증된다. 본 논문에서는 항공기 응답을 직접 비교함으로써 개발된 비행제어법칙의 상사성과 HILS 환경의 신뢰성을 검증하였다.

• 한국시뮬레이션학회논문지
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• 제27권3호
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• pp.53-63
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• 2018

미래 전장 환경이 복잡하고 다양화됨에 따라 조직에 적절한 구조 및 편성을 작성하는 것도 간단하지 않은 일이 되었다. 이에 본 연구에서는 육군의 미래 제대별 참모부 편성을 시스템 다이내믹스를 활용하여 검증하는 방법론을 제시한다. 참모부 구조 및 편성 검증을 위한 SD 활용 절차는 입력 DB값 산출, 인과지도 작성 및 모델 구축, 모의 및 분석 순으로 진행된다. 시스템 다이내믹스를 활용한 모의분석의 취약점은 입력 값에 따라 결과가 달라질 수 있고 모의인원의 관점에 따라 분석이 달라질 수 있다는 것이다. 본 연구에서는 이에 대한 보완책으로 연구 분석, 설문 등을 병행하여 종합분석에 포함하는 방법을 적용하였다. 본 연구의 의의는 군조직의 구조 및 편성을 검증하기 위한 과학적인 방법으로 조직편성의 적절성을 정량화하여 판단할 수 있는 전투실험 방법을 제시함으로써 그 활용 가치가 크다고 판단된다.