• 기술사
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• 제22권2호
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• pp.19-25
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• 1989

Utilizing a cosine transform in image compression has several recognized performance benefits, resulting in the ability to attain large compression ratio with small quality loss. Also, various models incorporating Human Visual System (HVS) to Discrete Cosine Trans-form (DCT) scheme are considered. Using the exact frequency components of DCT basis function, the optimum modulation transfer function (MTF) is obtained analytically. The errors at a block boundary which is important factor in transform coder are criteria for error measurement. The HVS weight coding results in perceptually higher quality images compared with the unweighted scheme.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.10-15
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• 2004

A machining processes for flange panel has been introduced. Contrary to the conventional methods like forming and welding, roll-seaming method has been utilized for better quality and less cost. Several measurement methods including digital image processing have been used to confirm the product quality assurance.

• 한국안전학회지
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• 제34권4호
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• pp.15-21
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• 2019

In order to secure the safety of various machinery, it is very important to develop a technique for accurately and quickly measuring the cracks generated in the mechanical equipment and evaluating the mechanical characteristics. The evaluation of the mechanical properties is accompanied by an appropriate strain measurement according to the material and crack occurrence of the target structure. Especially, when micro cracks are generated, the evaluation method is very important. Digital image correlation is an optical full field displacement measuring method which is using currently with speckles in the interested area. However the evaluation method and conditions of image distributions have to be considered carefully to measure the crack occurrence because the images of the speckle patterns affect the quality of displacement results. In this study, the speckle pattern density is characterized to improve the accuracy of the measurement method. And also the micro crack initiation is detected by the measured displacement in the adopted speckle pattern distribution. It is shown that the proposed method is useful to determine the density pattern distribution for the accurate measurement and crack detection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2241-2243
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• 2005

Although the boundary image sticking is one of major factors to determine display quality in AC PDP, a reliable measurement method has not reported so far. The boundary image sticking is recognized clearly by our eyes, but it is difficult to compare with adjacent cells by using a measurement method. However, the boundary image sticking can be analyzed by CCD DSLR camera method because this method can distinguish between the boundary cell and the adjacent cells. Moreover, we suggested new driving waveform for the reduction of the boundary image sticking.

• 마케팅과학연구
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• 제20권1호
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• pp.98-109
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• 2010

对于品牌资产的组成, 测量和管理的研究开始于David A.Aaker (1991) 和Kevin Lane Keller(1993). 最近, 很多的研究都集中于品牌资产的组成: 品牌意识, 质量预期, 产品形象和品牌忠诚度. 本文主要针对于这些成分间相互关系, 而且特别主意产品种类(实用或者享受)的调节作用. 基于以上所提及的关系所建立的模型可以参看图1. 本文的假设如下: 顾客的品牌意识对于顾客的忠诚度和品牌形象有积极的影响; 顾客的质量预期对于品牌忠诚度和品牌形象有积极的影响; 品牌形象对于品牌忠诚度有积极影响; 这些品牌资产成分间的关系可以被产品种类所调节. 具体说明就是, 对于实用性产品, 质量预期对于品牌忠诚度的作用会增强, 而对于享受产品品牌形象对于品牌忠诚度的作用会更强. 为了确定适用于本研究的产品, 58名首尔的大学生参加了前测. 结果是计算机被选择成为实用性产品, 而牛仔裤被选定成为享受产品. 每一种产品各选择了两个品牌: 三星和惠普以及李维斯和NIX. 在研究中, 首尔地区的237名大学生回答了问卷. 研究对象被划分为两组: 一组(121名)回答关于计算机的问卷, 其他的116名回答关于牛仔裤的问卷. 搜集的数据通过AMOS 7来验证可信度, 效度以及变量间的相互关系. 验证性因子分析证明本研究的模型是可以用来进一步研究的. 品牌资产成分间的相互关系也通过AMOS 7 来验证. 结果模型的结果展现在图2中. 质量预期对于品牌的形象有积极的影响, 但是品牌意识却没有. 但是品牌意识, 质量预期, 以及品牌形象都对品牌忠诚度有积极的影响. 并且, 这些关系受到产品种类的调节. 本文的研究结果可以增进我们对于品牌资产成分间相互关系的了解, 并且可以支撑对于品牌资产的测量. 本文也对于产品种类的作用进行了阐述. 在现实的营销管理中, 这些结果可以提供一些建议来有效保持品牌资产.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4043-4064
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• 2021

Night-time image quality evaluation is an urgent requirement in visual inspection. The lighting environment of night-time results in low brightness, low contrast, loss of detailed information, and colour dissonance of image, which remains a daunting task of delicately evaluating the image quality at night. A new blind quality assessment metric is presented for realistic night-time scenario through a comprehensive consideration of contrast, texture, and colour in this article. To be specific, image blocks' color-gray-difference (CGD) histogram that represents contrast features is computed at first. Next, texture features that are measured by the mean subtracted contrast normalized (MSCN)-weighted local binary pattern (LBP) histogram are calculated. Then statistical features in Lαβ colour space are detected. Finally, the quality prediction model is conducted by the support vector regression (SVR) based on extracted contrast, texture, and colour features. Experiments conducted on NNID, CCRIQ, LIVE-CH, and CID2013 databases indicate that the proposed metric is superior to the compared BIQA metrics.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권2호
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• pp.91-96
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• 2004

In darkroom condition, it was observed that a white picture pattern lasted several minutes leaves a recognizable trace in subsequent black background picture. Although this is not a serious problem for the most current public display or home TV applications, the image sticking should be minimized for future high quality multimedia display applications. In order to characterize this picture memory effect having relatively long time scale, spatially resolved luminance measurement and light waveform measurement have been performed. Pixels located at the outer boundary of white pattern previously displayed shows highest luminance. These cells also shows fastest ignition at the ramp up reset sequence. The luminance and ignition voltage differences between boundary cells and the other cells are increased with display duration and number of sustain-pulse. It is speculated that image sticking observed at the boundary cell is originated from the transport of charged particles and re-deposition of reactive species such as Mg, O provided from strong sustain discharge region.

• Computers and Concrete
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• 제10권4호
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• pp.409-417
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• 2012

The quality of high performance concrete largely depends on water cement ratio, porosity, material composition and mix methods. The uniformity of color, texture and compressive strengths are quality indicators commonly used to assess the overall characteristics of concrete mixes. The homogeneity and share of coarse aggregates play a key role in concrete quality and must be analyzed in a microscopic point of view. This research studies the quality of high performance concrete by taking drilled cores in both horizontal and vertical directions from a 1.0 $m^3$ specimen. The coarse aggregate, expressed in digitized $100{\times}116$ dpi resolution images are processed based on brightness in colors through commercial software converted into text files. With the image converting to text format, the share of coarse aggregate is quantified leading to a satisfactory assessment of homogeneity - a quality index of high performance concrete. The compressive strengths of concrete and the shares of coarse aggregate of the samples are also compared in this research study to illustrate its correlation in concrete quality. It is concluded that a higher homogeneity of aggregate exists in the vertical plane than that of the horizontal planes of the high performance concrete. In addition, the concrete specimen showing denser particle packing has relatively higher compressive strengths. The research methodology provides an easy-to-use, direct measurement of high performance concrete when conducting quality assessment in the construction site.

• Journal of Welding and Joining
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• 제12권3호
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• pp.109-117
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• 1994

Spot welding has wide used with a high work efficiency in the automotive and aerospace industries. Up to the present, the technique mainly used to test spot welds on production lines has been entirely depended upon destructive chisel or peel testing. Therefore, it's being very important assignment to secure the NDE technique which can be evaluate spot weld quality with more efficiency and high reliability. This paper discusses the feasibility of UNDE techniques to evaluate spot weld quality. For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of a the corona bond from nugget, ultrasonic c-scan image and distribution of reflective echo amplitude was measured by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). As the results of this study, corona bond which is the most dangerous types of interface defects can be successfully detected, as well as expulsion and voids. Ultrasonic testing results were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be successfully measured with the accuracy of 0.8 mm.

• 한국산업정보학회논문지
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• 제5권3호
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• pp.65-70
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• 2000

일반적으로 농산물의 품질은 무게나 크기 등을 직접 측정하여 판정하거나 간접 또는 비파괴방법을 이용하여 판정하게 된다. 본 논문에서는 비파괴를 이용한 판정방법인 칼라 영상처리를 이용하여 농산물의 품질과 등급을 결정하는 알고리즘을 개발하여, 이를 실시간 귤 분류시스템에 적용하였다. 개발된 시스템은 귤의 크기와 색상을 칼라 영상처리 하여 초당 최대 6개를 실시간 분류 할 수 있는 성능을 가지고 있다. 또한 다른 농산물의 품질판정을 위한 제어기를 설계할 경우에도 본 논문에서 개발한 알고리즘이 적용될 수 있을 것으로 기대된다.