• Title/Summary/Keyword: TOF(Time Of Flight Method)

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Preliminary study of time-of-flight measurement for 3D position sensing system based on acoustic signals

  • Kim, Heung-Gi;Park, Youngjin
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.79.4-79
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    • 2002
  • Our goal is the development of a system that estimates the location of interested point in a room with accuracy and low cost. Non-contacting position estimating method is widely used in various areas. Among these methods, acoustic signal-based method is the cheapest and provides reasonably accurate estimation as a result of many research efforts. Most of the acoustic-signal-based three-dimensional location estimators such as 3D sonic digitizer are using the ultrasound, and are organized with two procedures; time-of-flight (TOF) estimation and localization estimation. Since the errors in estimating the TOF could be accumulated with that of localization estimate, accuracy of TOF estimate is as...

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Low Resolution Depth Interpolation using High Resolution Color Image (고해상도 색상 영상을 이용한 저해상도 깊이 영상 보간법)

  • Lee, Gyo-Yoon;Ho, Yo-Sung
    • Smart Media Journal
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    • v.2 no.4
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    • pp.60-65
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    • 2013
  • In this paper, we propose a high-resolution disparity map generation method using a low-resolution time-of-flight (TOF) depth camera and color camera. The TOF depth camera is efficient since it measures the range information of objects using the infra-red (IR) signal in real-time. It also quantizes the range information and provides the depth image. However, there are some problems of the TOF depth camera, such as noise and lens distortion. Moreover, the output resolution of the TOF depth camera is too small for 3D applications. Therefore, it is essential to not only reduce the noise and distortion but also enlarge the output resolution of the TOF depth image. Our proposed method generates a depth map for a color image using the TOF camera and the color camera simultaneously. We warp the depth value at each pixel to the color image position. The color image is segmented using the mean-shift segmentation method. We define a cost function that consists of color values and segmented color values. We apply a weighted average filter whose weighting factor is defined by the random walk probability using the defined cost function of the block. Experimental results show that the proposed method generates the depth map efficiently and we can reconstruct good virtual view images.

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Identification of Salmonella spp. from porcine salmonellosis by matrix-assisted laser desorption ionization-time of flight mass spectrometry

  • Yang, Hyoung-Seok;Kim, Jae-Hoon
    • Korean Journal of Veterinary Service
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    • v.41 no.2
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    • pp.105-110
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    • 2018
  • A total of 41 Salmonella (S.) strains were isolated from pigs suffered with severe watery diarrhea and were tried to identify by both matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction (PCR) analysis. Fibrinous exudate and ulceration in the large intestine were prevalent in gross observation, and variable degrees of enteritis were observed in the histology of large intestines. Subsequent polymerase chain reaction (PCR) analyses demonstrated that 41 strains were identified as S. Typhimurium (39 strains), though 2 stains were failed to identify. Further identification was performed using both direct smear and protein extraction method by MALDI-TOF MS analyses. In terms of extraction methods, 100% (41/41) of isolates were identified to species level of S. spp. Whereas only 43.9% (18/41) were identified to species level using the direct method. These results thus suggest that rapid and accurate diagnosis of porcine salmonellosis can be guaranteed by MALDI-TOF MS combined with protein extraction method.

Rapid Identification of Staphylococcus Species Isolated from Food Samples by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

  • Kim, Eiseul;Kim, Hyun-Joong;Yang, Seung-Min;Kim, Chang-Gyeom;Choo, Dong-Won;Kim, Hae-Yeong
    • Journal of Microbiology and Biotechnology
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    • v.29 no.4
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    • pp.548-557
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    • 2019
  • Staphylococcus species have a ubiquitous habitat in a wide range of foods, thus the ability to identify staphylococci at the species level is critical in the food industry. In this study, we performed rapid identification of Staphylococcus species using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight mass spectrometry (MALDI-TOF MS). MALDI-TOF MS was evaluated for the identification of Staphylococcus reference strains (n = 19) and isolates (n = 96) from various foods with consideration for the impact of sample preparation methods and incubation period. Additionally, the spectra of isolated Staphylococcus strains were analyzed using principal component analysis (PCA) and a main spectra profile (MSP)-based dendrogram. MALDI-TOF MS accurately identified Staphylococcus reference strains and isolated strains: the highest performance was by the EX method (83.3~89.5% accuracy) at species level identification (EDT, 70.3~78.9% accuracy; DT, less than 46.3~63.2% accuracy) of 24-h cultured colonies. Identification results at the genus level were 100% accurate at EDT, EX sample preparation and 24-h incubation time. On the other hand, the DT method showed relatively low identification accuracy in all extraction methods and incubation times. The analyzed spectra and MSP-based dendrogram showed that the isolated Staphylococcus strains were characterized at the species level. The performance analysis of MALDI-TOF MS shows the method has the potential ability to discriminate between Staphylococcus species from foods in Korea. This study provides valuable information that MALDI-TOF MS can be applied to monitor microbial populations and pathogenic bacteria in the food industry thereby contributing to food safety.

Estimation of the Axial Stress in High-Tension Bolt by Acoustoelastic Method (음탄성법을 이용한 고장력 볼트의 축응력 평가)

  • Chun, Hae-Hwa;Lee, Tae-Hoon;Jhang, Kyung-Young;Kim, Noh-Yu
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.5
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    • pp.285-290
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    • 2006
  • The evaluation of clamping condition has been regarded as the main issue in the safety-maintenance of the clamped high-tension bolts. For this, this paper proposes a method to estimate the axial stress by measuring the TOF (Time-Of-Flight) of ultrasonic wave, which is based on the acoustoelasticity or the dependency of sound speed on the stress. In this method, however, the variation of sound speed within the range of stress induced under the field condition is very small, and thus the accuracy of the TOF measurement is important. We adopted the phase detection method using tone-burst ultrasonic wave to measure the precise TOF. In order to verify the usefulness of the proposed method experiments are carried out and the results were compared with the stress measured by the strain gage. The results show good agreement with each other, and from these we can conclude that the proposed method is highly useful fnr the evaluation of clamping condition in the clamped high-tension bolts.

Characterization of Poly(ethylene oxide)-b-Poly(L-lactide) Block Copolymer by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

  • Jeongmin Hong;Donghyun Cho;Taihyun Chang;Shim, Woo-Sun;Lee, Doo-Sung
    • Macromolecular Research
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    • v.11 no.5
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    • pp.341-346
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    • 2003
  • A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

Applications of MALDI-TOF Mass Spectrometry in Clinical Microbiology

  • Shin, Kyeong Seob;Yum, Jonghwa
    • Biomedical Science Letters
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    • v.28 no.3
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    • pp.145-156
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    • 2022
  • Over the past few decades, few technologies have had a greater impact on clinical microbiology laboratories than matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS). The MALDI-TOF MS is a fast, accurate, and low-cost and efficient method of microbial identification. This technology generates characteristic mass spectral fingerprints that is a unique signature for each microorganism, making it an ideal method for accurate identification at the genus and species levels of both bacterial and fastidious microorganism such as anaerobes, mycobacterium and fungi etc. In addition, MALDI-TOF MS has been successfully used in microbial subtyping and susceptibility tests such as determination of resistance genes. In this study, the authors summarized the application of MALDI-TOF MS in clinical microbiology and clinical research and explored the future of MALDI-TOF MS.

Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

  • Jeong, Young-Su;Lee, Jonghee;Kim, Seong-Joo
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2635-2639
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    • 2013
  • The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field.

MALDI TOF MS for the identification of Salmonella spp. from swine (돼지유래 Salmonella속 균의 동정을 위한 MALDI TOF MS 활용)

  • Sohn, Jun Hyung;Jeon, Woo Jin;Lee, Young Mi;Kim, Seon Soo
    • Korean Journal of Veterinary Service
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    • v.39 no.4
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    • pp.247-251
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    • 2016
  • Salmonella is one of the most common bacteria that causes heavy losses in swine industry and major causative pathogen of food poisoning in public health. Various methods for the identification of Salmonella such as Gram staining, agglutination test, enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR) have been used. Several studies have demonstrated that Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI TOF) Mass Spectrometry (MS) identification is an efficient and inexpensive method for the rapid and routine identification of isolated bacteria. In this study, MALDI TOF MS could provide rapid, accurate identification of Salmonella spp. from swine compared with end point PCR and real time PCR.

A Computation Method for Time of Flight in the Anti-Aircraft Gun Fire Control System (대공화기 탄자비행시간 계산 기법)

  • Kim, Jaehun;Kim, Euiwhan;Yu, Sukjin;Kim, Sungho
    • KIPS Transactions on Computer and Communication Systems
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    • v.4 no.11
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    • pp.361-368
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    • 2015
  • In AAGFCS the effective range is regarded as a range for the bullet's speed exceeding the speed of sound to damage the stationary target. Hence the real engagement range might be extended over the effective range for the approaching target since bullet's relative speed to the target increases depending on the approaching speed. However previous TOF equations have good computation accuracy within the effective range only, and they can not be used above that range due to their bad accuracy. We propose an accurate TOF computation method which can be used both within and above the effective range in real time. Some simulation results are shown to demonstrate usefulness of our algorithm for the 30mm projectile.