• 한국정보과학회논문지:데이타베이스
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• 제32권2호
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• pp.129-141
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• 2005

시공간 데이타베이스는 최근에 많은 주목을 받았지만, 영역 합 질의에 대한 연구는 그 중요성에 비하여 많이 부족하다. 영역 합 질의를 처리하기 위하여, 많은 양의 데이타에 대한 직접적인 접근은 엄청난 계산 비용을 야기하기 때문에, 최근에 기존 색인 기법을 활용한 materialization 방법이 제안되었다. 간단하면서 효과적인 방법은 시공간 조건을 가지는 윈도우 질의를 효율적인 처리하는 MVR-tree에 materialization 방법을 적용하는 것이다. 그러나, MVR-tree는 노드들 사이의 존재하는 원형 경로 때문에, 중간 노드에 미리 계산된 합을 유지하는 것이 불가능하다. 다른 색인 구조들에 기초한 집합적 구조(aggregate structures)는 만족스러운 질의 성능을 제공하지 못 한다. 본 논문에서는 적응적 분할 기법을 사용하는 새로운 색인 기법(Adaptive Partitioned Aggregate R-Tree, APART)과 다양한 환경에서 영역합 질의를 효율적으로 처리하는 질의 처리 알고리즘을 제안한다. 실험 결과는 APART의 성능이 다양한 상황에서 기존의 집합적 색인 기법들보다 2배 이상 우월하다는 것을 보여준다.

• 대한안전경영과학회지
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• 제8권4호
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• pp.195-204
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• 2006

This paper deals with a batch processor model in which the batch processing speed depends on the jobs assigned to the batch. Each job is completed by accomplishing its required job processing quantity which is calculated as job speed product processing time. Its speed is given as not the exact value but the range. Thus the batch sets are constructed by the jobs which hold the speed in common. And the batch sets are processed as soon as possible. We developed the model to described the problem situation and adopt the total tardiness as the decision criterion.

• 한국수산과학회지
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• 제54권4호
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• pp.561-567
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• 2021

The edible sargasso seaweed hijiki Sargassum fusiforme is known to have high concentration of arsenic, which is a threat to human health, particularly due to inorganic arsenic. In this study, various methods were used to remove inorganic arsenic from steamed hijiki concentrate. The highest concentration of arsenate [As(V)] in both raw and processed hijiki during steamed hijiki manufacturing process was within the range of 8.213-14.356 mg/kg, and it is a potential source of inorganic arsenic, which can result in re-contamination and cause environmental pollution. The removal efficiencies of the various removal methods were within the range of 57.3-83.4%, and 19.0% reduction was achieved using activated carbon and alginate bead. Further, activated carbon showed the best adsorption effect of inorganic arsenic. Therefore, we suggest that activated carbon is a suitable efficient method for removing inorganic arsenic and has low operational costs in field applicability.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2359-2364
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• 2017

This paper proposes a scale factor based range estimation method using a sum of squares (SOS) method. Many previous studies measured distance by using a camera, which usually required two cameras and a long computation time for image processing. To overcome these disadvantages, we propose a range estimation method for an object using a single moving camera. A SOS-based Luenberger observer is proposed to estimate the range on the basis of the Euclidean geometry of the object. By using a scale factor, the proposed method can realize a faster operation speed compared with the previous methods. The validity of the proposed method is verified through simulation results.

• 한국군사과학기술학회지
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• 제13권1호
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• pp.140-146
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• 2010

The multi-function radar can detect and track the low RCS targets. For this purpose the multi-function radar uses the pulse train waveform. because this waveform has high dynamic range and good SNR(Signal to Noise Ratio). But the spurious signals can also be detected by processing the pulse train waveform. Thus the multi-function radar signal processor must have the high SFDR(Spurious Free Dynamic Range). This paper describes the development of the multi-function radar signal processor having the high SFDR.

• 한국전자파학회논문지
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• 제13권8호
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• pp.777-782
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• 2002

일반적인 시간 영역에서의 레이더 신호들은 표적의 관측각에 민감하게 변화한다. 따라서 대표적인 시간영역 레이더 신호인 1차원 range profile을 이용하여 구분실험을 하는 경우에 있어서 central moments와 PCA를 결합하여 먼저 특성벡터를 추출한 후 clustering 기법에 기반한 subclass concept을 사용하는 구분기를 사용하여 넓은 관측각에서의 표적인식 성능을 향상시킨 결과들을 보여준다.

• 한국전자통신학회논문지
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• 제19권2호
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• pp.335-343
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• 2024

본 논문은 FMCW LiDAR의 실시간 표적 신호처리 기법에 관해 기술하고 있다. FMCW LiDAR는 높은 검출민감도를 가져 낮은 출력만으로 장거리 측정이 가능하면서도 눈, 비, 안개 등 열악한 환경에서 강건한 검출성능을 가져 자율주행자동차용 차세대 LiDAR로 주목받고 있다. 본 논문은 주파수 영역의 신호처리를 위해 필요한 고속 데이터 획득, 전송 및 병렬 신호처리를 위한 하드웨어 구조에 대해 기술하였다. 획득된 시계열 신호로부터 주파수 특성을 분석하기 위하여, 푸리에 변환 연산을 FPGA로 구현하였다. 변환된 주파수영역 데이터로부터 강건한 표적검출 성능을 확보하기 위한 C-FAR 알고리즘에 대해 기술하였다. 표적의 스펙트럼 신호로부터 주파수 측정값의 해상도를 향상하고, 측정된 주파수 값을 표적의 거리 및 속도 정보로 변환하는 과정에 대해 상세히 기술하였다. 스캐너 2D 위치 및 표적의 거리 정보를 활용하여 3차원 영상으로 변환하고 이를 전시하였다. 제안된 FPGA 구조의 병렬 신호처리 알고리즘 적용을 통하여 FMCW LiDAR의 실시간 표적 신호처리 및 고해상도 영상획득 성능을 확인하였다.

• Design & Manufacturing
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• 제18권2호
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• pp.23-28
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• 2024

The automobile industry is a wide range of related industries, including parts manufacturing and vehicle assembly, press processing is an essential element in making automobiles. Press processing is a processing method for metal sheets that has relatively high dimensional and shape precision and is suitable for mass production. It refers to processing by attaching a special tool, a mold, to a press machine. Recently, the automobile industry is attempting to reduce the weight of automobiles in order to reduce carbon emissions due to global warming, and the use of high-strength steel sheets, which are lighter than general structural steel sheets, is a natural trend. Shear processing is required to use high-strength steel, and the shape of the shear surface created by shear processing has a significant impact on the quality of the automobile. Therefore, various methods are being attempted to improve the share surface during shear processing. Among them, shaving processing is a method of shearing the primary shearing area again, and it is difficult to obtain an accurate answer because complex deformation occurs in the microscopic shear area. Therefore, in this study, the effect of machining allowance on shaving processing was analyzed using the finite element method using high-strength steel plate (SPFH590), and the differences were compared and examined through actual experiments under the same conditions.

• 전자공학회논문지S
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• 제34S권10호
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• pp.59-70
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• 1997

Until now, considerable progress has been made in the application of range finding techanique performing direct 3-D measurement from the object. However, ther are few use of the method in the area of the application of material handing. We present a range finding vision system consisting of static and dynamic range finders to automate a reclaimer used for material handling. A static range finder detects range data of the front part of the piles of material, and a height map is obtained from the proposed image processing algorithm. The height map is used to calculate the optimal job path as features for required information for material handling function. A dynamic range finder attached on the side of the arm of the reclaimer detects the change of the local properties of the material with the handling function, which is used for avoiding collision and detecting the ending point for changing direction. the developed vision systm was applied to a 1/20 simulator and the results of test show that it is appropriate to use for automating the material handling.

• International Journal of Advanced Culture Technology
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• 제6권4호
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• pp.190-194
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• 2018

The runway visual range is one of the important factors that decide the possibility of taking offs and landings of the airplane at local airports. The runway visual range is affected by weather conditions like fog, wind, etc. The pilots and aviation related workers check a local weather forecast such as runway visual range for safe flight. However there are several local airfields at which no other forecasting functions are provided due to realistic problems like the deterioration, breakdown, expensive purchasing cost of the measurement equipment. To this end, this study proposes a prediction model of runway visual range for a local airport by applying convolutional neural network that has been most commonly used for image/video recognition, image classification, natural language processing and so on to the prediction of runway visual range. For constituting the prediction model, we use the previous time series data of wind speed, humidity, temperature and runway visibility. This paper shows the usefulness of the proposed prediction model of runway visual range by comparing with the measured data.