• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.45-50
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• 2001

An approach of composing a performance optimized computational code is suggested for latest microprocessors. The approach named as localization is a concept of minimizing the access to system's main memory and maximizing the utilization of second level cache that is common to all the latest computer system. The localized compositions of LU-SGS scheme for fluid dynamics were made in three different levels and tested on three different microprocessor architectures most widely used in these days. The test results of localization concept showed a remarkable performance, that is the showing gain up to 4.5 times faster solution than the baseline algorithm $450\%$ for producing an exactly the same solution.

• 기술사
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• 제45권3호
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• pp.23-27
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• 2012

This tractate inform that the localization of equipment has led to strong competitiveness through enact a provision of electricity(KEC : Korea Electrical Code) made by Korea Electric Association.

• 대한전자공학회논문지TC
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• 제45권4호
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• pp.9-21
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• 2008

이 논문은 위성항법시스템의 문제점들을 해결하기 위하여 GNSS 기반의 RF 수신단과 고정밀 측위 아키텍처 그리고 고감도 측위 아키텍처를 제안하였다. GNSS 기반의 RF 수신단 모델은 기존 GPS와 향후 사용되어질 갈릴레오의 항법정보데이터를 동시에 수신할 수 있는 구조를 가져야 한다. 따라서 GPS의 L1대역인 1575.42MHz와 갈릴레오의 El대역인 1575.42MHz, E5A대역인 1207.1MHz 그리고 E5B대역인 1176.45MHz를 동시에 수신할 수 있는 다중 밴드로 구성하였다. 고정밀 측위 아키텍처는 기존 상관기 구조가 가지고 있는 Early코드, Prompt코드, Late코드를 사용하는 1/2칩 이격 구조가 아닌 Early_early코드, Early_late코드, Prompt코드, Late_early코드, Late_late 코드 구조의 상관기를 제안하였다. 이렇듯 1/4칩 이격의 상관기 구조를 제안하여, 위성항법시스템으로부터 송신되는 신호의 부정확성으로 인해 생기는 C/A코드와의 동기 문제를 해결하였다. C/A코드와의 동기 문제는 차량용 항법시스템의 동기 획득 지연 시간 문제가 발생되어, 수신기의 성능 저하를 가져온다. 다음으로 고감도 측위 아키텍처는 20개의 코럴레이터(correlator)를 사용하여 비대칭 구조로 설계하여 수신 증폭률을 최대화하고, 잡음을 최소화하여 수신율을 향상시키도록 하였다. 위성항법시스템은 동일한 C/A코드를 20번 반복하여 전송한다. 따라서 동일한 C/A코드를 모두 사용할 수 있는 구조를 제안하였고, 적응형 구조를 가지고 있어, 주변 환경에 따라 코럴레이터의 수를 제한할 수 있어, 불필요한 시스템의 동작 지연 시간을 줄일 수 있다. 이러한 구조의 사용으로 동기 획득 지연 시간을 줄일 수 있고, 동기 추적의 연속성을 보장할 수 있다. 이는 위성항법시스템의 수신기 성능을 향상시키는 결과를 가져온다.

• 한국항공우주학회지
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• 제30권7호
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• pp.68-80
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• 2002

최신 마이크로프로세서에서 성능 최적화된 수치 코드를 작성하는 접근법을 제시하였다. 국소화로 지칭한 이 코드 최적화 방법은 모든 최신 마이크로프로세서에서 채용되는 2차 캐시의 사용을 최대화하고 시스템의 주기억장치에 대한 접근을 최소화하는 개념이다. 본 연구에서는 유체역학 문제의 해결을 위한 LU-SGS 해법을 3 단계에 걸쳐 국소화 하였으며, 요즈음 널리 이용되고 있는 여러 가지 마이크로프로세서들에 대해 시험을 수행하였다. 국소 최적화 개념의 시험 결과는, 컴퓨터 시스템에 따라서는, 같은 컴퓨터에서 완전히 동일한 해를 기본 알고리즘에 비해 7.35배까지 빨리 얻을 수 있는 주목할 만한 성능을 보여 주었다.

• 로봇학회논문지
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• 제12권3호
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• pp.350-355
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• 2017

UWB (Ultra Wide Band) refers to a system with a bandwidth of over 500 MHz or a bandwidth of 20% of the center frequency. It is robust against channel fading and has a wide signal bandwidth. Using the IR-UWB based ranging system, it is possible to obtain decimeter-level ranging accuracy. Furthermore, IR-UWB system enables acquisition over glass or cement with high resolution. In recent years, IR-UWB-based ranging chipsets have become cheap and popular, and it has become possible to implement positioning systems of several tens of centimeters. The system can be configured as one-way ranging (OWR) positioning system for fast ranging and TWR (two-way ranging) positioning system for cheap and robust ranging. On the other hand, the ranging based positioning system has a limitation on the number of terminals for localization because it takes time to perform a communication procedure to perform ranging. To overcome this problem, code multiplexing and channel multiplexing are performed. However, errors occur in measurement due to interference between channels and code, multipath, and so on. The measurement filtering is used to reduce the measurement error, but more fundamentally, techniques for removing these measurements should be studied. First, the TWR based positioning was analyzed from a stochastic point of view and the effects of outlier measurements were summarized. The positioning algorithm for analytically identifying and removing single outlier is summarized and extended to three dimensions. Through the simulation, we have verified the algorithm to detect and remove single outliers.

• IEIE Transactions on Smart Processing and Computing
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• 제4권3호
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• pp.173-182
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• 2015

A real-time, Indoor navigation systems utilize ultra-wide band (UWB), radio-frequency identification (RFID) and received signal strength (RSS) techniques that encompass WiFi, FM, mobile communications, and other similar technologies. These systems typically require surplus infrastructure for their implementation, which results in significantly increased costs and complexity. Therefore, as a solution to reduce the level of cost and complexity, an inertial measurement unit (IMU) and quick response (QR) codes are utilized in this paper to facilitate navigation with the assistance of a smartphone. The QR code helps to compensate for errors caused by the pedestrian dead reckoning (PDR) algorithm, thereby providing more accurate localization. The proposed algorithm having IMU in conjunction with QR code shows an accuracy of 0.64 m which is higher than existing indoor navigation techniques.

• 동력기계공학회지
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• 제17권5호
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• pp.100-111
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• 2013

Indoor real-time positioning for multiple targets is required to realize human-robot symbiosis. This study firstly presents positioning accuracy on an autonomous mobile robot controlled by 3-D coordinates that is obtained by a real-time indoor positioning system with spread spectrum (SS) ultrasonic signals communicated by code-division multiple access. Although many positioning systems have been investigated, the positioning system with the SS ultrasonic signals can measure identified multiple 3-D positions in every 70 ms with noise tolerance and error within 100 mm. This system is also robust to occlusion and environmental changes. However, thus far, the positioning errors in an autonomous mobile robot, controlled by these systems using the SS ultrasonic signals, have not been evaluated as an experimental study. Therefore, a positioning experiment for trajectory control is conducted using an autonomous mobile robot and our positioning system. The effectiveness of this positioning method for robot self-localization is shown, from this experiment, because the average control error between the target position and the robot's position at 29 mm is obtained.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.423-428
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• 2005

This paper proposes a new edge detection method using a $3{\times}3$ ideal binary pattern and lookup table (LUT) for the mobile robot localization without any parameter adjustments. We take the mean of the pixels within the $3{\times}3$ block as a threshold by which the pixels are divided into two groups. The edge magnitude and orientation are calculated by taking the difference of average intensities of the two groups and by searching directional code in the LUT, respectively. And also the input image is not only partitioned into multiple groups according to their intensity similarities by the histogram, but also the threshold of each group is determined by fuzzy reasoning automatically. Finally, the edges are determined through non-maximum suppression using edge confidence measure and edge linking. Applying this edge detection method to the mobile robot localization using projective invariance of the cross ratio. we demonstrate the robustness of the proposed method to the illumination changes in a corridor environment.

• 반도체디스플레이기술학회지
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• 제10권2호
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• pp.31-38
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• 2011

This paper introduces a video based traffic monitoring system for detecting vehicles and obstacles on the road. To segment moving objects from image sequence, we adopt the background subtraction algorithm based on the local binary patterns (LBP). Recently, LBP based texture analysis techniques are becoming popular tools for various machine vision applications such as face recognition, object classification and so on. In this paper, we adopt an extension of LBP, called the Diagonal LBP (DLBP), to handle the background subtraction problem arise in vision-based autonomous parking systems. It reduces the code length of LBP by half and improves the computation complexity drastically. An edge based shadow removal and blob merging procedure are also applied to the foreground blobs, and a pose estimation technique is utilized for calculating the position and heading angle of the moving object precisely. Experimental results revealed that our system works well for real-time vehicle localization and tracking applications.

• 한국멀티미디어학회논문지
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• 제21권11호
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• pp.1305-1316
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• 2018

Graphical user interface(GUI) has a very important role to interact with software users. However, designing and coding of GUI are tedious and pain taking processes. In many studies, the researchers are trying to convert GUI elements or widgets to code or describe formally their structures by help of domain knowledge of stochastic methods. In this paper, we propose the GUI elements detection approach based on object detection strategy using deep neural networks(DNN). Object detection with DNN is the approach that integrates localization and classification techniques. From the experimental result, if we selected the appropriate object detection model, the results can be used for automatic code generation from the sketch or capture images. The successful GUI elements detection can describe the objects as hierarchical structures of elements and transform their information to appropriate code by object description translator that will be studied at future.