• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.121-125
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• 2004

The effectiveness of the pogo suppression device (PSD) installed at the piping system simulating the fuel supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $(0,\;0.5,\;1,\;2\times10^{-6}\;m^3)$. Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, though the fluctuations of the main tube pressure and the flow rate damped down considerably

• Journal of Korean Gerontological Nursing
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• v.20 no.3
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• pp.167-176
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• 2018

Purpose: Post Stroke Depression (PSD) is one of the most common complications for stroke survivors and is associated with negative health outcomes such as disability, death. The purpose of this study was to investigate the prevalence and predictors of PSD among older Korean adults living in the community. Methods: Data collection was done using the 2014 Survey of Living Conditions and Welfare Needs of Korean Older Adults. Participants were 706 older adults who had a stroke. Logistic regression analysis was used to determine the predictors of PSD. Results: The prevalence of PSD which was assessed by the short form of the geriatric depression scale was 49.4%. In a logistic regression model, the predictors of PSD were self-rated health (OR=5.90, CI=3.70~9.40), economic state (OR=2.97, CI=2.07~4.24), independent activities of daily living (IADL) (OR=2.17, CI=1.30~3.63), Activities of Daily Living (ADL) (OR=2.02, CI=1.07~3.80), and education (OR=1.53, CI=1.05~2.24). Conclusion: PSD was common among older Korean adults living in the community. Poor self-rated health status, lower economic state, lower levels of Instrumental Activities of Daily Living (IADL) and ADL, lower levels of education should be considered when conducting activities related to prevention and management of PSD in older adults.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1051-1058
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• 2018

This paper propose image processing algorithm to prevent safety accidents near by subway platform screen door(PSD). First, edges of the subway PSD images are detected and the boundary line between PSD and subway platform is detected to decide people's approach to the PSD using Hough transform. To do this, we draw the boundary line between the PSD and platform, to detect the boundary line and to decide the people's approach to the detected line is completely connected or not. Generally, edge is the basic characteristic of image; thus, edge detection is very important in image processing applications and computer vision area. The conventional edge detection methods such as Roberts, Sobel, Prewitt, and Laplacian etc, which are using a fixed value of mask, and morphological gradient from the structuring element of view and Canny edge detector are widely used. In this paper, we propose the detection algorithm about the people's approach to the subway PSD to prevent the safety accidents by using Canny edge detector and Hough transform and the computer simulation shows the results.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.158-162
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• 2010

PSD is automatically opened and closed when subway train arrive on the station. This system was designed to control electric automatic system. These doors will provide passenger safety, energy saving and a good environment in subway. The monitoring and control systems of PSD are configured so that they can be operated in automatic mode in connection with ATO through the composite control panel in the station control room. The objective of this paper is to obtain high reliability that is essential for monitoring and control systems of PSD. The power supply is based on protection circuit using DC power bridge from two UPS. Also, stable communication system consists of CAN communication line redundancy and RF cross protection algorithm. Monitoring state display results show the validity of the proposed high reliability monitoring and control systems of PSD.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1587-1593
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• 2008

After the incendiary fire accident at Daegu subway, discussion of PSD installation started to prevent accident from fall. safety accident and big accident. Following these paradigm, the purpose of the study is to analyze the present condition of current installation of PSD in our country and suggest an improvement scheme for the future PSD operation extension. Using the SWOT analysis and we analyze the inner and outer capability of PSD installation. We try to find a counter plan strategy for PSD installation improvement scheme through the analysis.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.223-231
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• 2018

Since the introduction of PSD in 2005, the number of accidents involving passengers falling onto the tracks accidentally or intentionally have drastically decreased, but the number of PSD related passenger accidents is increasing. While existing papers on PSD have been devoted to systemic introduction and system improvement, papers on passenger casuality accidents due to deteriorated PSD have been limited. This paper proposes revising of the scenario model for passenger accidents using classified hazard sources of PSD.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1025-1026
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• 2008

This paper describes a monocular PSD-based motion capture sensor to employ with commercial video game systems such as Microsoft's XBOX and Sony's Playstation II. The system includes a PSD(Position Sensitive Detector) and active infrared (IR) LED markers that are placed on the object to be tracked. The micro-controller calculates the 3D position of the markers using only the measured intensity and the 2D position on the PSD. A series of experiments were performed to evaluate the performance of our prototype system. From the experimental results we see that the proposed system has the advantages of the compact size, the low cost, the easy installation, and the high frame rates to be suitable for high speed motion tracking in games.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.10-18
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• 2003

In the present study, several different types of PSD performance test systems were reviewed. Basically there are two methods to pulsate the system; whole-feeding-system pulsation and working-fluid pulsation. The latter method adopts either a piston-type pulsator or a restrict-type pulsator The working-fluid pulsation using a restrict-type pulsator was considered to be the most appropriate experimental system to study the effects of the primary parameters, and a practical design of the system was proposed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1951-1962
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• 1993

The creation process of a typical machined surface is treated here as a dynamic system. An investigation is carried out to establish a relationship between the characteristics of cutting force fluctuations that cause vibration response of the tool-workpiece system and the formation of surface in face cutting by sintered carbide cutting tool. Cutting force is measured and analyzed in frequency domain. The power spectral densities of cutting force give a useful information in surface generation and it can be used to find out the control factor of surface roughness. The terms, PSD ratio & Normalized spindle frequency PSD, are defined and when the value of power in spindle frequency is absolutely little but relatively large, it is obtained high accuracy surface roughness. The aim of this research is to find surface profile by measured and analyzed cutting force signals. The simulation of surface generation gives the comprechension of its mechanism and help to predict and control the surface quality. In this study, it is suggested what informations about surface generation can be acquired from the cuttuing force signal and an way of generating a better surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.839-840
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• 2010