• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.62-67
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• 2000

Modern people stay at indoor places about 90% of a day. Radon-222 is a gas produced by the radioactive decay of the element radium. And, radon is one of the major indoor air pollutants. Radon moves into the underground space through various routes and is considered to cause lung cancer by hurting the lung tissues. In this study, we measured the subway radon level at 9 stations of 3 lines. According to test results, we can figure out the concentration of radon by lines, times, and measuring points. So, it was found that ventilation conditions are the most important factors in the subway air quality. Finally, we suggested effective and economic management methods of air pollution in the subway.

• International Journal of Contents
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• v.9 no.3
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• pp.9-14
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• 2013

In this paper, we will examine single face tracking algorithms with scaling function in a mobile device. Face detection and tracking either in PC or mobile device with scaling function is an unsolved problem. Standard single face tracking method with particle filter has a problem in tracking the objects where the object can move closer or farther from the camera. Therefore, we create an algorithm which can work in a mobile device and perform a scaling function. The key idea of our proposed method is to extract the average of skin color in face detection, then we compare the skin color distribution between the detected face and the tracking face. This method works well if the face position is located in front of the camera. However, this method will not work if the camera moves closer from the initial point of detection. Apart from our weakness of algorithm, we can improve the accuracy of tracking.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.145-148
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• 2000

Nowadays there are lots of researches on robot systems working on danger environments and control led remotely. In this paper, we describe a virtual robot interface system based on Internet In the system, a client can order scanning for range finding, then server detects a 3D profile data from the objects by using robot controlling and a range finder automatically. If one clicks the original position of object and destination on virtual space, the robot moves the object to the new position in real space. The proposed interface system supports advanced virtual 3D interface and makes it possible one to manage the objects remotely more conveniently.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.201-206
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• 2003

In clinical practice, CT Angiography is a powerful technique for the visualziation of blood flow in arterial vessels throughout the body. However CT Angiography images of blood vessels anywhere in the body may be fuzzy if the patient moves during the exam. In this paper, we propose a novel technique for removing global motion artifacts in the 3D space. The proposed methods are based on the two key ideas as follows. First, the method involves the extraction of a set of feature points by using a 3D edge detection technique based on image gradient of the mask volume where enhanced vessels cannot be expected to appear, Second, the corresponding set of feature points in the contrast volume are determined by correlation-based registration. The proposed method has been successfully applied to pre- and post-contrast CTA brain dataset. Since the registration for motion correction estimates correlation between feature points extracted from skull area in mask and contrast volume, it offers an accelerated technique to accurately visualize blood vessels of the brain.

• Journal of Drive and Control
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• v.18 no.3
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• pp.16-22
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• 2021

The variable structure controller has the characteristic that while in sliding mode, the system moves along the switching plane in the vicinity of the switching plane, so it is robust to the parameter fluctuations of the plant. However, a controller based on a variable structure may not meet the desired performance when it is commanded to track any input or exposed to disturbances. To solve this problem, a sliding mode controller based on the IVSC approach excluding an integrator is proposed in this study. The proposed sliding mode control was applied to the position control of a hydraulic cylinder piston. The sliding plane was determined by the pole placement and the control input was designed to ensure the existence of the sliding mode. The feasibility of the modeling and controller was reviewed by comparing it with a conventional proportional control through computer simulation using MATLAB software and experiment in the presence of significant plant parameter fluctuations and disturbances.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.64-71
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• 2022

Various types of attendance management systems are being introduced in a remote working environment and research on using face recognition is in progress. To ensure accurate worker's attendance, a face recognition-based attendance management system must analyze every frame of video, but face recognition is a heavy task, the number of the task should be minimized without affecting accuracy. In this paper, we proposed a search model using time interval variation to minimize the number of face recognition task of recorded videos for attendance management system. The proposed model performs face recognition by changing the interval of the frame identification time when there is no change in the attendance status for a certain period. When a change in the face recognition status occurs, it moves in the reverse direction and performs frame checks to more accurate attendance time checking. The implementation of proposed model performed at least 4.5 times faster than all frame identification and showed at least 97% accuracy.

• Journal of the Korea Safety Management & Science
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• v.26 no.3
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• pp.115-121
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• 2024

The forklift carry cargo and move to various places. When a forklift moves to various places, a forklift accident occurs due to a number of factors,such as speed, safe distance. Forklift accidents occur at the logistic site and there are many studies on the causes of accident such as jamming, falling, collisions, etc. However, safety operation for accident prevention is necessary before operating a forklift. Pre-accident safety precautions may prevent accidents. In this study, precautionary factors for safe operation were analyzed to prevent forklift safety accidents through the AHP technique. As a result of the study showed that safety management was the priority in the terminal group and the logistics warehouse group.

• Journal of IKEEE
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• v.28 no.3
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• pp.465-468
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• 2024

In this paper, we propose a synthetic aperture radar based on FMCW using a nonlinear radar platform. we construct a nonlinear radar platform with different transmit and receive frequencies using FMCW signals. The platform moves along a 1.5 m path to acquire second harmonics signals, implementing a nonlinear SAR (synthetic aperture radar). Multiple nonlinear targets were placed in an indoor multipath environment with linear objects to detect weak second harmonics. After undergoing the SAR focusing precess, a 2D hamming window was applied to enhance the focusing performance.

• Kyungpook Mathematical Journal
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• v.64 no.3
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• pp.511-518
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• 2024

A 2n-move is a local change for knots and links which changes 2n-half twists to 0-half twists or vice versa for a natural number n. In 1979, Yasutaka Nakanishi conjectured that the 4-move is an unknotting operation. This is still an open problem. It is known that the Γ-polynomial is an invariant for oriented links which is the common zeroth coefficient polynomial of the HOMFLYPT and Kauffman polynomials. In this paper, we show that the 4k-move is not an unknotting operation for any integer k(≥ 2) by using the Γ-polynomial, and if Γ(K; -1) ≡ 9 (mod 16) then the knot K cannot be deformed into the unknot by a single 4-move. Moreover, we give a one-to-one correspondence between the value Γ(K; -1) (mod 16) and the pair (a₂(K), a₄(K)) (mod 2) of the second and fourth coefficients of the Alexander-Conway polynomial for a knot K.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.177-182
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• 2015

Nevertheless 3D printer is propagated fast, it is difficult for us of using 3D printer at the same time because of 3D printer's slow velocity. Existing solution is to print using SD card which moves files and on PC but this method is spend too much time and can not be showed status of printing. Yet we have no 3D printer software solution which is controlled and printed remotely. Therefore, this 3D printer software solution makes 3D printer be connected on internet networks and selected to use it on smart App. And it is controlled and printed remotely. In my paper, to build an Android App. which can execute these functions, an effective analysis & design using UML and implementation method will be presented.