• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.25-28
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• 2004

Photocurrent spectrum, photoresponse, and I-V measurements were made for close-packed HgTe nanoparticles without organic capping materials to investigate their photocurrent characteristics in the infrared range. In absorption and photoluminescence (PL) spectra taken for the close-packed nanoparticles film, the wavelengths of exciton peaks was red-shifted, compared with organic capped HgTe nanoparticles dispersed in solution. This red-shift is caused by the lessening of the exciton binding energy. The I-V curves and photoresponse for the close-packed nanoparticles film reveal their dark current and fast photoresponse with no current decay, respectively. The observation suggests that the HgTe nanoparticles are a very prospect material applicable for photodetectors in the whole IR range.

• Journal of Korean Neurosurgical Society
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• v.63 no.2
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• pp.248-260
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• 2020

Objective : To investigate the efficiency of diffusion tensor imaging (DTI) fiber-tracking based neuronavigation and assess its usefulness in the preoperative surgical planning, prognostic prediction, intraoperative course and outcome improvement. Methods : Seventeen patients with cerebral masses adjacent to corticospinal tract (CST) were given standard magnetic resonance imaging and DTI examination. By incorporation of DTI data, the relation between tumor and adjacent white matter tracts was reconstructed and assessed in the neuronavigation system. Distance from tumor border to CST was measured. Results : The sub-portion of CST in closest proximity to tumor was found displaced in all patients. The chief disruptive changes were classified as follows : complete interruption, partial interruption, or simple displacement. Partial interruption was evident in seven patients (41.2%) whose lesions were close to cortex. In the other 10 patients (58.8%), delineated CSTs were intact but distorted. No complete CST interruption was identified. Overall, the mean distance from resection border to CST was 6.12 mm (range, 0-21), as opposed to 8.18 mm (range, 2-21) with simple displacement and 2.33 mm (range, 0-5) with partial interruption. The clinical outcomes were analyzed in groups stratified by intervening distances (close, <5 mm; moderated, 5-10 mm; far, >10 mm). For the primary brain tumor patients, the proportion of completely resected tumors increased progressively from close to far grouping (42.9%, 50%, and 100%, respectively). Five patients out of seven (71.4%) experienced new neurologic deficits postoperatively in the close group. At meantime, motor deterioration was found in six cases in the close group. All patients in the far and moderate groups received excellent (modified Rankin Scale [mRS] score, 0-1) or good (mRS score, 2-3) rankings, but only 57.1% of patients in the close group earned good outcome scores. Conclusion : DTI fiber tracking based neuronavigation has merit in assessing the relation between lesions and adjacent white matter tracts, allowing prediction of patient outcomes based on lesion-CST distance. It has also proven beneficial in formulating surgical strategies.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.27-32
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• 2015

This paper describes a distance measurement system with high accuracy that utilizes a stereo-based camera and a pan-tilt unit for automatically maintaining the positional relationship between a vessel and a target on the side of a facility at a close range. The measurement system offers an advantage in that it can measure the distance to a target while tracking it. In order to improve the ability to control the position of a vessel between it and a target while maintaining the distance especially at a close range, the accuracy of the measurement system has to be improved. The accuracy of the distance measured by our system is increased with revisions of the conclusively generated data of distance measurement. We verified the accuracy of our system from an experiment, which generated results that had an accuracy of 30 mm for distances in the range between 2-8 m.

• Journal of Information Processing Systems
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• v.15 no.5
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• pp.1082-1095
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• 2019

Camera calibration is an important part of machine vision and close-range photogrammetry. Since current calibration methods fail to obtain ideal internal and external camera parameters with limited computing resources on mobile terminals efficiently, this paper proposes an improved fast camera calibration method for mobile terminals. Based on traditional camera calibration method, the new method introduces two-order radial distortion and tangential distortion models to establish the camera model with nonlinear distortion items. Meanwhile, the nonlinear least square L-M algorithm is used to optimize parameters iteration, the new method can quickly obtain high-precise internal and external camera parameters. The experimental results show that the new method improves the efficiency and precision of camera calibration. Terminals simulation experiment on PC indicates that the time consuming of parameter iteration reduced from 0.220 seconds to 0.063 seconds (0.234 seconds on mobile terminals) and the average reprojection error reduced from 0.25 pixel to 0.15 pixel. Therefore, the new method is an ideal mobile terminals camera calibration method which can expand the application range of 3D reconstruction and close-range photogrammetry technology on mobile terminals.

• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.59-67
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• 2018

As high-rise buildings came in, the landscape of rural areas and natural landscapes often got damaged. Therefore, this study aims to prevent this, grasp the extent of the influence of the surrounding landscape, to grasp the range of height that can be permitted and present the direction of landscape management of agriculture and natural landscape. This study tried to grasp the range of height by using price sensitivity analysis method for two apartment and apartment complex which entered DangJin city and SeoSan city. First, in the case of a two apartment, the range of the height allowable section was from the 6th floor to the 11th floor in close range view, and it was a section from the 7th floor to the 12th floor in medium range view. In the case of the apartment complex, the range of the height allowable range was from the 10th floor to the 17th floor in close range view, the 9th floor to the 16th floor in medium range view. The stress index was found to be positive in a two apartment in close range view, and in the apartment complex case. therefore it was better to set it to a lower in the Range of Acceptable Height(RAH). Second, it showed no difference in the sensitivity of landscape to gender. Thirdly, the results of the landscape sensitivity analysis of major and non-major showed the difference in the medium range view picture of the apartment complex. Majors are lower than the point of minimum height(PMinH) than non-Majors. In the case of major, the stress index was 1.4. it turned out that it was better to make a decision closer to point of minimum height (PMinH). In the case of non-major, the stress index was -1.3. it was also able to accept decision close to the point of maximum height (PMaxH). Since the results of the above research gave changes only in the variable of the height of the landscape, we can not grasp the point of interaction with other variables, and future research is considered necessary.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.644-662
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• 2023

There are still outbreaks of COVID-19 across the world. Ships increase the risk of worldwide transmission of the virus. Close contact tracing remains as an effective method of reducing the risk of virus transmission. Therefore, close contact tracing in ship environments becomes a research topic. Exposure Notifications API (Application Programming Interface) can be used to determine the encountered location points of close contacts on ships. Location points of close contact are estimated by the encountered location points. Risky areas in ships can be calculated based on the encountered location points. The tracking of close contacts is possible with Bluetooth technology without the Internet. The Bluetooth signal can be used to judge the proximity among detecting devices by using the feature that Bluetooth has a strong signal at close range. This Bluetooth feature makes it possible to trace close contacts in ship environments. In this paper, we propose a method for close contact tracing and showing the risky area in a ship environment by combining beacon and Exposure Notification API using Bluetooth technology. This method does not require an Internet connection for tracing close contacts and can protect the personal information of close contacts.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.561-568
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• 2011

The purpose of this study is to measure displacements that occurs on a surface and interior of slope model and the shape when the slope is destroyed at vibration experiment of the slope model using close range photogrammetry. The circle targets and sphere targets are installed on a chamber and a slope model, while the earthquake wave are applied in regular time interval. The close range photogrammetric images are acquired in each displacements step until the slope model is destroyed. Those photos are processed by image processing method and the center points of targets are automatically extracted. Furthermore, the three-dimensional coordinates of targets are calculated by image orientation and bundle adjustment processing. As a result, amount of displacement at each level is precisely measured and provided the basic information for assessing the slope stability using three-dimensional measurement of the target movement and slope destruction.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.23-29
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• 1990

Non-metric camera is more profitable than metric camera for geometric analysis of small and elaborate structures, because focal length control of non-metric camera is flexible while generally metric camera has limited focal length. And if the problem of conventional method requiring much time and endeavor to measure three dimensional positions of control points will be solved effectively, it is possible to analyze very close-range photogrammetry more easily and quickly. The purposes of this study are to propose the efficiency of non-metric camera and to reduce difficulty of control survey sharply by introducing self-control survey method. For these, very close-range photographs of the small object were obtained by using non-metric camera calibrated for systematic errors and then bundle adjustment is used for analysis procedure. As a result, the superiority of non-metric camera in analyzing very close-range photographs and the application proptriety of self-control survey were proved, therefore it is expected to be able to apply to precise analysis of small structures or spearhead parts.

• Journal of the Korean Geotechnical Society
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• v.24 no.2
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• pp.59-65
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• 2008

Digital close-range photogrammetric technique can measure and describe 3D geometric farm from 2D image. This technique is increasingly applied in the field of sciences. In the fields of civil and mechanical engineering, which need precise measurements for design, expensive measuring equipments are widely used. In occasions where visual inspection is required in addition to other forms of measurements, appropriate measuring equipments have not been yet available. This study utilizes digital close-range photogrammetric technique to quantitatively analyze behavior patterns before and after destruction from test model of reinforced-soil wall. Then the results are compared with the measurements obtained using digital theodolite to verify the reliability of the proposed method.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.123-133
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• 2005

This study has made photographing respectively by changing the converging angle by use of d7 $metric^5$ that is a measurement digital camera. And also in order to minimize the errors happened at the relative orientation, we have sorted out the round target that the relative orientation is automatically on the programming and have calculated RMSE by carrying out the bundle adjustment. We think that such a study could be used as very important basic data necessary in deriving the optimal photographic conditions by the close-range digital photogrammetry and in judging such a degree.