• Journal of Mechanical Science and Technology
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• 제15권2호
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• pp.232-238
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• 2001

Fast Fourier Transformation is employed to convert the head variation of a pipeline in the time domain to the amplitude of the frequency domain. Applying method of characteristics to a pipeline provides a significant frequency range for a surge introduced from the valve modulation. Inverse Fast Fourier Transformation and a Finite Impulse Response Filter can be used to remove any possible noise existing from the significant frequency range of an unsteady condition. A filtered signal shows higher potential for the inverse calculation of leakage detection than the noise-added signal does. The respective performances of Inverse Fast Fourier Transformation and a Finite Impulse Response Filter are compared in terms of leakage detection capability. Characteristics of the frequency range for multiple leakages were investigated to validate the effectiveness of the noise control method in the frequency domain.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.73-82
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• 2004

The deaerator of a power plant is one of feedwater heaters in the secondary system, and it is located above the feedwater pumps. The feedwater pumps take the water from the deaerator storage tank, and the net positive suction head(NSPH) should always be ensured. To secure the sufficient NPSH, the deaerator tank is equipped with the level control system of which level sensors are critical items. And it is necessary to ascertain the sensor state on-line. For this, a model-based fault detection and diagnosis(FDD) is introduced in this study. The dynamic control model is formulated from the relation of input-output flow rates and liquid-level of the deaerator storage tank. Then an adaptive state estimator is designed for the fault detection and diagnosis of sensors. The performance and effectiveness of the proposed FDD scheme are evaluated by applying the operation data of Yonggwang Units 3 & 4.

• 선박안전
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• 통권36호
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• pp.71-78
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• 2014

If we don't know the intention of altering course of a target ship when being in a head-on or a crossing situation, we may be confused about our decision making to change our course for collision avoidance and be in a danger of collision. In order to solve these problems, we need to develop an automatic detection system on altering course of a target ship for efficient collision avoidance. In this paper, we proposed an early detection system on altering course of a target ship using the steering wheel signal. This system will contribute to the reduction of collision accidents and also be used to the VTS system and the analysis of marine accidents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.610-630
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• 2020

A large number of people suffered from traffic accidents each year, so people pay more attention to traffic safety. However, the traditional methods use laser sensors to calculate the vehicle distance at a very high cost. In this paper, we propose a method based on deep learning to calculate the vehicle distance with a monocular camera. Our method is inexpensive and quite convenient to deploy on the mobile platforms. This paper makes two contributions. First, based on Light-Head RCNN, we propose a new vehicle detection framework called Light-Car Detection which can be used on the mobile platforms. Second, the planar homography of projective geometry is used to calculate the distance between the camera and the vehicles ahead. The results show that our detection system achieves 13FPS detection speed and 60.0% mAP on the Adreno 530 GPU of Samsung Galaxy S7, while only requires 7.1MB of storage space. Compared with the methods existed, the proposed method achieves a better performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권8호
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• pp.2199-2213
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• 2024

To enhance the quality of defect detection for Printed Circuit Board Assembly (PCBA) during electronic product manufacturing, this study primarily focuses on optimizing the YOLOv7-based method for PCBA defect detection. In this method, the Mish, a smoother function, replaces the Leaky ReLU activation function of YOLOv7, effectively expanding the network's information processing capabilities. Concurrently, a Squeeze-and-Excitation attention mechanism (SEAM) has been integrated into the head of the model, significantly augmenting the precision of small target defect detection. Additionally, considering angular loss, compared to the CIoU loss function in YOLOv7, the SIoU loss function in the paper enhances robustness and training speed and optimizes inference accuracy. In terms of data preprocessing, this study has devised a brightness adjustment data enhancement technique based on split-filtering to enrich the dataset while minimizing the impact of noise and lighting on images. The experimental results under identical training conditions demonstrate that our model exhibits a 9.9% increase in mAP value and an FPS increase to 164 compared to the YOLOv7. These indicate that the method proposed has a superior performance in PCBA defect detection and has a specific application value.

• Journal of Acupuncture Research
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• 제24권6호
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• pp.187-193
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• 2007

Objectives : The objectives of this study were to investigate the relationship between electrical detection of ear acupuncture points and musculoskeletal pain. Methods : 18 adults who have musculoskeletal pain without trauma factorsparticipated in this study. They answered the questionnaire and their ear acupuncture points were examined with electrical detectors. We analyzed the relationship between electrical detection of ear acupuncture points and musculoskeletal pain with concordance rate and validity. Results : Total concordance rates of the head region was 68.00%(questionnaire) 32.08%(investigation), that of vertebral region was 67.86%, 59.38%, that of both upper limbs was 86.67%, 39.69%, and that of both lower limbs was 50.00%, 23.46%. The true positive rate was 0.704, the true negative rate was 0.492, the false positive rate was 0.508, and the false negative rate was 0.296 in the validity test. In the head, two concordance rates of the temporal and occipital regions were relatively higher than those of the parietal and frontal regions. In the vertebral region, two concordance rates of the cervical and lumbar regions were relatively higher than those of the thoracic and sacrum regions. In the upper limb, two concordance rates of the shoulder and shoulder joints were relatively higher than those of the others. In the lower limb, concordance rates of investigation were relatively low at all areas. The right lower limb was relatively higher than the left in concordance rates of the questionnaire. Conclusions : The results suggest that electrical detection of ear acupuncture points can be used in the diagnosis and treatment of musculoskeletal pain.

• 대한의용생체공학회:의공학회지
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• 제25권2호
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• pp.145-150
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• 2004

시각장애인의 시각보조를 위하여 공간 및 방향감각 보조시스템으로 초음파거리계 및 전자나침반을 개발하였다. 초음파거리계는 40 KHz 초음파의 반사를 이용하여 장애물까지 거리 정보를 거리에 비례하는 시간간격의 가청음 자극을 제공하며, 전자나침반은 자기저항브리지를 이용하여 지구자기장을 검출하고 자북 방향 정보를 이마주위의 진동모터를 통하여 촉각자극을 제공하도록 설계하였다. 초음파저리계의 측정범위는 0.065-3.26미터이며 전자나침반의 방향 분해능은 22.5도이다. 그리고 초음파거리계와 전자나침반을 통합한 일체형 시각보조시스템을 구현하였으며 이때 거리정보는 두부에서 진동모터의 위치로 전달하도록 하였다. 본 연구의 목표는 시각장애인의 공간 및 방향감각을 위한 실용적인 보조시스템을 구현하는 것이며, 본 보조시스템을 반복 사용함에 따라 시각장애인의 공간 및 방향감각 기능이 향상될 것으로 추측된다.

• 정보처리학회논문지B
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• 제14B권4호
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• pp.311-320
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• 2007

본 논문에서는 강건한 얼굴 포즈 추정과 실시간 표정제어가 가능한 비전 기반 3차원 얼굴 모델의 자동 표정 생성 방법 및 시스템을 제안한다. 기존의 비전 기반 3차원 얼굴 애니메이션에 관한 연구는 얼굴의 움직임을 나타내는 모션 추정을 반영하지 못하고 얼굴 표정 생성에 초점을 맞추고 있다. 그러나, 얼굴 포즈를 정확히 추정하여 반영하는 작업은 현실감 있는 얼굴 애니메이션을 위해서 중요한 이슈로 인식되고 있다. 본 연구 에서는 얼굴 포즈추정과 얼굴 표정제어가 동시에 가능한 통합 애니메이션 시스템을 제안 하였다. 제안된 얼굴 모델의 표정 생성 시스템은 크게 얼굴 검출, 얼굴 모션 추정, 표정 제어로 구성되어 있다. 얼굴 검출은 비모수적 HT 컬러 모델과 템플릿 매칭을 통해 수행된다. 검출된 얼굴 영역으로부터 얼굴 모션 추정과 얼굴 표정 제어를 수행한다. 얼굴 모션 추정을 위하여 3차원 실린더 모델을 검출된 얼굴 영역에 투영하고 광류(optical flow) 알고리즘을 이용하여 얼굴의 모션을 추정하며 추정된 결과를 3차원 얼굴 모델에 적용한다. 얼굴 모델의 표정을 생성하기 위해 특징점 기반의 얼굴 모델 표정 생성 방법을 적용한다. 얼굴의 구조적 정보와 템플릿 매칭을 이용하여 주요 얼굴 특징점을 검출하며 광류 알고리즘에 의하여 특징점을 추적한다. 추적된 특징점의 위치는 얼굴의 모션 정보와 표정 정보의 조합으로 이루어져있기 때문에 기하학적 변환을 이용하여 얼굴의 방향이 정면이었을 경우의 특징점의 변위인 애니메이션 매개변수(parameters)를 계산한다. 결국 얼굴 표정 복제는 두 개의 정합과정을 통해 수행된다. 애니메이션 매개변수 3차원 얼굴 모델의 주요 특징점(제어점)의 이동은 획득된 애니메이션 매개변수를 적용하여 수행하며, 정점 주위의 부가적 정점의 위치는 RBF(Radial Basis Function) 보간법을 통해 변형한다. 실험결과 본 논문에서 제안된 비전기반 애니메이션 시스템은 비디오 영상으로부터 강건한 얼굴 포즈 추정과 얼굴의 표정변화를 잘 반영하여 현실감 있는 애니메이션을 생성함을 입증할 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4957-4961
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• 2014

Background: Head and neck cancer without distant metastases is amenable to various modalities of treatment. However, the stage at presentation is a very important determinant for treatment success. The present study was conducted to determine the stage-wise presentation of non-metastatic head and neck cancer patients from the hilly regions in Kumaon division of Uttarakhand, India. Materials and Methods: The hospital records for non-metastatic head and neck cancer patients from the only functional cancer centre of the region for the period of two-years (January 2012-December 2013) were included. Nasopharyngeal carcinoma was excluded due to its staging system being different. Non-squamous histopathologies were also excluded. Patients hailing from nearby regions of Uttar Pradesh and Nepal were excluded, as were patients from non-hilly regions of Kumaon. Results: Of the 271 patients of head and neck cancer, 27 with distant metastases at diagnosis were excluded from the analysis. Of the 244 eligible patient records, 90.1% (n=222) were male, and 9.9% (n=22) were female. The proportions of patients with carcinoma of the larynx, oropharynx, oral cavity, hypopharynx and maxillary antrum were 31.9% (n=78), 27.9% (n=68), 20.5% (n=50), 12.7% (n=31) and 1.2% (n=3). A further 5.7% (n=14) were diagnosed as having secondary involvement of neck nodes with unknown primaries. The proportion of patients presenting in stages I, II, III, IVA and IVB were 0.8% (n=2), 2.5% (n=6), 9.4% (n=23), 51.6% (n=126) and 35.7% (n=87) respectively. Conclusions: An abysmally low proportion (3.3%) of non-metastatic head and neck cancer patients presented in the early stages (I and II). A vast majority of the patients (88.1%) presented with stages IVA and IVB. Not only does this reflect a poor therapeutic outlook, but also exposes the dire need for programmes focusing on cancer awareness and early detection in the region.

• 대한두경부종양학회지
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• 제12권2호
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• pp.201-205
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• 1996

이상의 성적에서 레이저 성대 절제술은 초기 성문암종에 대한 일차 치료법으로 유용하다고 생각되었으며, 일차 절제가 가장 중요하고 그후 성대를 포함한 전체 후두점막에 대하여 주기적으로 현수후두경하에 수술현미경을 이용한 추적관찰과 원격전이 및 이차암의 발생 유무에 대하여 적극적인 추적검사가 필요할 것으로 사료된다.