• Title/Summary/Keyword: Large-area measurement

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Refractive media flatness measurement by phase shifting digital holography (위상천이 디지털 홀로그래피를 이용한 평판의 표면 평면도 측정)

  • Jeon, Sung-Bin;Kim, Do-Hyung;Cho, Jang-Hyun;Park, No-Cheol;Yang, Hyun-Seok;Park, Kyoung-Su;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.8 no.2
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    • pp.44-49
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    • 2012
  • We measured the surface flatness of both sides for refractive media using the transmitted digital holography method. To enhance the accuracy of the result, phase-shifting system was used. With two different phase modulation of reference beam, the phase profile of object can be easily obtained. Thus, we proposed the surface measurement method which can measure large area fast, compared with conventional methods. To guarantee the reliability of obtained result, we compared with Zygo measurement system. With the proposed method, the surface flatness of $3.45{\mu}m$ resolution could be obtained.

Measuring plagiarism in the second language essay writing context (영작문 상황에서의 표절 측정의 신뢰성 연구)

  • Lee, Ho
    • English Language & Literature Teaching
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    • v.12 no.1
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    • pp.221-238
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    • 2006
  • This study investigates the reliability of plagiarism measurement in the ESL essay writing context. The current study aims to address the answers to the following research questions: 1) How does plagiarism measurement affect test reliability in a psychometric view? and 2) how do raters conceive the plagiarism in their analytic scoring? This study uses the mixed-methodology that crosses quantitative-qualitative techniques. Thirty eight international students took an ESL placement writing test offered by the University of Illinois. Two native expert raters rated students' essays in terms of 5 analytic features (organization, content, language use, source use, plagiarism) and made a holistic score using a scoring benchmark. For research question 1, the current study, using G-theory and Multi-facet Rasch model, found that plagiarism measurement threatened test reliability. For research question 2, two native raters and one non-native rater in their email correspondences responded that plagiarism was not a valid analytic area to be measured in a large-scale writing test. They viewed the plagiarism as a difficult measurement are. In conclusion, this study proposes that a systematic training program for avoiding plagiarism should be given to students. In addition, this study suggested that plagiarism is measured reliably in the small-scale classroom test.

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Similarity measurement based on Min-Hash for Preserving Privacy

  • Cha, Hyun-Jong;Yang, Ho-Kyung;Song, You-Jin
    • International Journal of Advanced Culture Technology
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    • v.10 no.2
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    • pp.240-245
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    • 2022
  • Because of the importance of the information, encryption algorithms are heavily used. Raw data is encrypted and secure, but problems arise when the key for decryption is exposed. In particular, large-scale Internet sites such as Facebook and Amazon suffer serious damage when user data is exposed. Recently, research into a new fourth-generation encryption technology that can protect user-related data without the use of a key required for encryption is attracting attention. Also, data clustering technology using encryption is attracting attention. In this paper, we try to reduce key exposure by using homomorphic encryption. In addition, we want to maintain privacy through similarity measurement. Additionally, holistic similarity measurements are time-consuming and expensive as the data size and scope increases. Therefore, Min-Hash has been studied to efficiently estimate the similarity between two signatures Methods of measuring similarity that have been studied in the past are time-consuming and expensive as the size and area of data increases. However, Min-Hash allowed us to efficiently infer the similarity between the two sets. Min-Hash is widely used for anti-plagiarism, graph and image analysis, and genetic analysis. Therefore, this paper reports privacy using homomorphic encryption and presents a model for efficient similarity measurement using Min-Hash.

Measurement of wave propagation environment in Korean terrain and comparison with the environments(models) of the other nations in pager system (무선호출 주파수 전파환경측정 및 외국 환경과의 비교)

  • 이형수;조삼모;정진욱
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.6 no.3
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    • pp.15-23
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    • 1995
  • The antenna height of the mobile communications lower than its typical surroundings causes multipath fading usually resulting in fast fluctuations of both signal strength and wave length in mobile radio communications. Therefore, there have been developed and used various wave be- havior prediction models, in some other foreign countries, based on the measurement data rather than on theoretical derivation. The main purpose of this paper is to examine the wave propagation characteristics particularly in Korean terrain with the measurements made in four types of different areas - a large city area, a small city area, a flat terrain area, and a mountain area. Those areas have been classified according to the terrain characteristics with which the particular area contains, such as scale and number of buildings, highways, trees, and so on. With the measured data of the field strength in the frequency band of pager system obtained from those four different areas, we compared the calculated ones from both Hata's and TIREM prediction models which are often applied in Korea.

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Development of a Smartphone-based Pupillometer

  • Kim, Tae-Hoon;Youn, Jong-In
    • Journal of the Optical Society of Korea
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    • v.17 no.3
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    • pp.249-254
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    • 2013
  • In ophthalmology, a pupillometer, a device to measure the diameter of the pupil of the eye, can provide information on the function of the autonomic nervous system. The current pupillometers on the market are either too large to be a handheld instrument, or relatively expensive. In this study, a pupillometer based on a smartphone was designed. Both white and infrared LEDs and a 3M pixel camera of a smartphone were applied for the visual stimuli to an eye and for the acquisition of the eye images, respectively. Contrary to the existing method of pupil measurement that usually observe the variation of pupil diameter, the proposed algorithm in this study was applied to calculate the constriction ratio of the pupillary area in response to pupillary light reflex. The results showed that the constriction ratio of the pupillary area were all in the normal range (above 4.0) from the sixteen healthy participants. It is believed that the approach to pupil measurement used in this study is suitable for a mobile interface, and this system can be applied to clinical research, home-use healthcare, and distributed to some areas which suffer from problems like a lack of medical support.

3D scanner's measurement path establishment automation by robot simulator

  • Jang, Pyung-Su;Lee, Sang-Heon;Chang, Min-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2179-2182
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    • 2005
  • Recently, optical 3D scanners are frequently used for inspection of parts, assembly and manufacturing tooling. One of the advantages is being able to measure a large area fast and accurately. Owing to recent advances in high-resolution image sensing technology, high power illumination technology, and high speed microprocessors, the accuracy and resolution of optical 3D scanners are being improved rapidly. In order to measure the entire geometry of objects, multiple scans have to be performed in various setups by moving either the objects or the scanner. This paper introduces novel methods to measure the entire geometry of objects by automatically changing the setups and then aligning the scanned data in a single coordinate system.

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A Study on Automatic Measurement of Pronunciation Accuracy of English Speech Produced by Korean Learners of English (한국인 영어 학습자의 발음 정확성 자동 측정방법에 대한 연구)

  • Yun, Weon-Hee;Chung, Hyun-Sung;Jang, Tae-Yeoub
    • Proceedings of the KSPS conference
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    • 2005.11a
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    • pp.17-20
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    • 2005
  • The purpose of this project is to develop a device that can automatically measure pronunciation of English speech produced by Korean learners of English. Pronunciation proficiency will be measured largely in two areas; suprasegmental and segmental areas. In suprasegmental area, intonation and word stress will be traced and compared with those of native speakers by way of statistical methods using tilt parameters. Durations of phones are also examined to measure speakers' naturalness of their pronunciations. In doing so, statistical duration modelling from a large speech database using CART will be considered. For segmental measurement of pronunciation, acoustic probability of a phone, which is a byproduct when doing the forced alignment, will be a basis of scoring pronunciation accuracy of a phone. The final score will be a feedback to the learners to improve their pronunciation.

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The Improved Joint Bayesian Method for Person Re-identification Across Different Camera

  • Hou, Ligang;Guo, Yingqiang;Cao, Jiangtao
    • Journal of Information Processing Systems
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    • v.15 no.4
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    • pp.785-796
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    • 2019
  • Due to the view point, illumination, personal gait and other background situation, person re-identification across cameras has been a challenging task in video surveillance area. In order to address the problem, a novel method called Joint Bayesian across different cameras for person re-identification (JBR) is proposed. Motivated by the superior measurement ability of Joint Bayesian, a set of Joint Bayesian matrices is obtained by learning with different camera pairs. With the global Joint Bayesian matrix, the proposed method combines the characteristics of multi-camera shooting and person re-identification. Then this method can improve the calculation precision of the similarity between two individuals by learning the transition between two cameras. For investigating the proposed method, it is implemented on two compare large-scale re-ID datasets, the Market-1501 and DukeMTMC-reID. The RANK-1 accuracy significantly increases about 3% and 4%, and the maximum a posterior (MAP) improves about 1% and 4%, respectively.

Measurement and Compensation of Synchronization Error in Offset Printing Process (오프셋 인쇄에서의 동기화 오차 정밀 계측 및 보정 연구)

  • Kang, Dongwoo;Kim, Hyunchang;Lee, Eonseok;Choi, Young-Man;Jo, Jeongdai;Lee, Taik-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.6
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    • pp.477-481
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    • 2014
  • Flexible electronics have been to the fore because it is believed that flexibility can add incredible value such as light weight and mobility into the existing electronic devices and create new markets of large-area and low-cost electronics such as wearable eletronics in near future. Offset printing processes are regarded as major candidates for manufacturing the flexible electronics because they can provide the patterning resolution of micron-size effectively in large-area. In view of mechanics, the most important viewpoint in offset printing is how to achieve the synchronized movement of two contact surfaces in order to prevent slip between two contact surfaces and distortion of the blanket surface during ink transfer so that the high-resolution and good-overlay patterns can be printed. In this paper, a novel low-cost measurement method of the synchronization error using the motor control output signals is proposed and the compensation method is presented to minimize the synchronization error.

Connectivity and Effectiveness of Marine Protected Areas on the West Coast of Korea within the Yellow Sea Large Marine Ecosystem

  • Lee, Eun-Kyung;Lee, Junseok;Lee, Chang-Rae;Choi, Keun-Hyung
    • Ocean and Polar Research
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    • v.44 no.3
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    • pp.249-260
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    • 2022
  • This mini review examines the habitat connectivity and effectiveness of Korean Marine Protected Areas (MPAs) in the Yellow Sea Large Marine Ecosystem (YSLME) region. We first reemphasize that the Korean region of the YSLME is a single ecosystem (ecoregion) given the biophysical distribution patterns. The MPAs within the YSLME contribute about 50% to the total MPAs in Korea, accounting for about 10% of the territorial sea waters of Korea and 20% of the waters of YSLME on the Korean side. By area, national parks account for nearly 45% of the MPAs, followed by the wetland protected areas at 25%, with other types of MPA comprising the remaining 30%. Large MPA (> 100 km2) is the dominant type of MPA, accounting for 90% of the total area. We find that MPAs in the region are connected physically and perhaps also genetically. However, the level of protection was found to be low, and a no-take zone is rarely implemented. In addition, interrupted freshwater discharge caused by river-mouth dams poses a major hindrance to the physical connectivity of the MPAs. Restoration of the river-mouth dams and strengthened regulation on MPAs, with further expansion of MPAs in line with the current development of post-2020 global biodiversity frameworks, should be priorities for better management of marine resources. The newly revised law incorporating the concept of "Marine Ecosystem Axis Management" would reinforce the processes, and their effectiveness together with overall management of MPAs in Korea should be evaluated by designing appropriate measurement tools.