• Journal of Astronomy and Space Sciences
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• 제19권1호
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• pp.25-30
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• 2002

Black hole binary candidates are known to be composed of a black hole with 10 $M_{\odot}$ and a K or M type companion. Because the companion is believed to fill the Roche lobe that is very aspherical, the light curves of black hole binaries are characterized by an ellipsoidal variation. It has been known that the ellipsoidal light curves exhibit asymmetric maximum brightness at the orbital phases 0.25 and 0.75, which has been attributed to star spots or the hot impact points of the accretion flow on to the accretion disk around the black hole. In this paper, it is pointed out that the special relativistic beaming effect contributes to the asymmetry of several percent often observed in the light curves. The typical orbital velocity 400 km $s^{-1}$ observed in black hole binaries may induce the temperature difference $\DeltaT/T$ ~ 1/400 of the late type companion star in the observer`s rest frame, because of the special relativistic Doppler beaming effect. This difference in temperature can result in several per cent of brightness sensitively dependent on the wavelength band, which is comparable to what has been observed in most black hole binary candidates. Considering the significant contribution of the special relativistic Doppler beaming effect, we conclude that the estimation of the sizes and temperatures of the star spots or the hot impact point needs serious revision.

• Journal of Korean Academy of Nursing
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• 제8권2호
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• pp.39-49
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• 1978

The present research set out to further validate the results that Stromborg (1976) obtained in which a correlation (r= .22, p < .001) was found between the femininity of woman nursing students and their image of nursing. In addition the experimenter set out to elucidate any possible differences in the image of nursing according to (a) religion, (b) the motivation for choosing nursing as well as, (c) the particular area in which the students hoped to work after graduating. The research was conducted by presenting questionnaire type scales including a femininity scale and a nursing image scale, to 301 graduating students attending 4 Three-year nursing schools located within Seoul from November 21st, 1978 to November 30th. The results: 1. There was clearly no relation between femininity and the image of nursing as such (r= .01, p > .43). But upon analyzing the results along five subdimensions of the nursing image variable it was discovered that : (a) if femininity is low, the nursing student tend to view the educational preparation for becoming a nurse in a more positive light (r= -.10, p < .05), and (b) if femininity is high, the students tend to perceive their social role with a positive frame of mind (r= .15, p < .005). 2. There was a significant difference found in the image of nursing as related to the religion of the nursing students, The means ranked as follows (high scores indicate a positive image of the nursing profession). Catholic > Protestant > no religion > Buddhist 3, The difference in the nursing image according to motivation for sellecting the profession emerged as quite significant (F=6.92, p < .001). The rank of the means when the subject group is divided along the dimension of motive is as follows (ranking begins with the most positive nursing image): (a) The profession itself seemed good; (b) after marriage one can do a social type of activity; (c) significant others’advice: (d) the profession matches their high school grade record; (e) it matches the economic situation of the student; (f）no particular reason for their choice: (g) it's easy to get a nursing job after graduation. 4. The particular area of nursing one intended to go into after graduation varied significantly in terms of the image of nursing (F=3.03, p < .005). The means when ranked starting with those having the most positive image of the profession: (a) nurses helping deliveries; (b) hospital nurses: (c) nursing education; (d) school nurses: (e) government nurse supervisors: (f）public health nurses: (g) (students not going into any profession); (h) (students not going into the nursing profession but into some other area).

• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권8호
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• pp.1-11
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• 1998

One of the desired features for the realizations of high quality Information and Telecommunication services in future is "the Sensation of Reality". This will be achieved only with the visual communication based on the 3- dimensional (3-D) moving images. The main difficulties in realizing 3-D moving image communication are that there is no developed data transmission technology for the hugh amount of data involved in 3-D images and no established technologies for 3-D image recording and displaying in real time. The currently known stereoscopic imaging technologies can only present depth, no moving parallax, so they are not effective in creating the sensation of the reality without taking eye glasses. The more effective 3-D imaging technologies for achieving the sensation of reality are those based on the multiview 3-D images which provides the object image changes as the eyes move to different directions. In this paper, a multiview 3-D imaging system composed of 8 CCD cameras in a case, a RGB(Red, Green, Blue) beam projector, and a holographic screen is introduced. In this system, the 8 view images are recorded by the 8 CCD cameras and the images are transmitted to the beam projector in sequence by a signal converter. This signal converter converts each camera signal into 3 different color signals, i.e., RGB signals, combines each color signal from the 8 cameras into a serial signal train by multiplexing and drives the corresponding color channel of the beam projector to 480Hz frame rate. The beam projector projects images to the holographic screen through a LCD shutter. The LCD shutter consists of 8 LCD strips. The image of each LCD strip, created by the holographic screen, forms as sub-viewing zone. Since the ON period and sequence of the LCD strips are synchronized with those of the camera image sampling adn the beam projector image projection, the multiview 3-D moving images are viewed at the viewing zone.

• Journal of Navigation and Port Research
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• 제39권1호
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• pp.77-82
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• 2015

Slamming means that the hull hits the waves and receives impact pressure. This slamming effect may cause harm to people and when you put the hull at risk. so it is very harmful for cargo safety. Therefor slamming impact pressure should be fully considered in ship designing. In this study the model of wedged type structure are produced aimed to simulate a free fall that the experiments were carried out on different weight and free fall height. The flow field has been obtained by 2-frame grey level cross correlation PIV(Particle Image Velocimetry) method and experiment was divided into water entry and water exit. The impact pressure of free fall structure by a pressure acquisition system apply to dewetron system. The angles between a model and the water surface are adapted $15^{\circ}$ respectively. The weight change of models was given as 1.5, 1.8 and 2.0kg. To study slamming phenomenon for free fall height the experiments were carried out by the free fall height of 100, 200 and 300mm. The experimental value of the impact pressure according to the changes in weight was increase impact pressure in proportion to the increase in weight and higher free falling height has also influenced the increase in impact pressures.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제32권2A호
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• pp.85-95
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• 2012

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.

• Journal of the Korea institute for structural maintenance and inspection
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• 제19권5호
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• pp.56-66
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• 2015

This study aims at developing a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. Seismic resistant test of anchored and welded steel plate connections manifested an average of 2.8 times increase in the maximum loading (average 591.8 kN) in comparison to unreinforced beam-column specimen. The maximum drift ratios were also shown between 1.4% and 2.7%. An analytical study was performed while assuming the RC column on the right side and the vertical element of the reinforced PC panel to behave in completely composite manner and the RC column on the left side and PC panel to behave in completely non-composite manner when loading was exerted from upper right end of RC frame of specimen to its left side. It was found with the assumptions that the overall flexural behavior in principle agreed with the experimental result.

• Journal of Ocean Engineering and Technology
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• 제33권2호
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• pp.168-177
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• 2019

KRISO (Korea Research Institute of Ship & Ocean Engineering) started a project to develop the core algorithms for autonomous intervention using an underwater robot in 2017. This paper introduces the development of the robot platform for the core algorithms, which is an ROV (Remotely Operated Vehicle) type with one 7-function manipulator. Before the detailed design of the robot platform, the 7E-MINI arm of the ECA Group was selected as the manipulator. It is an electrical type, with a weight of 51 kg in air (30 kg in water) and a full reach of 1.4 m. To design a platform with a small size and light weight to fit in a water tank, the medium-size manipulator was placed on the center of platform, and the structural analysis of the body frame was conducted by ABAQUS. The robot had an IMU (Inertial Measurement Unit), a DVL (Doppler Velocity Log), and a depth sensor for measuring the underwater position and attitude. To control the robot motion, eight thrusters were installed, four for vertical and the rest for horizontal motion. The operation system was composed of an on-board control station and operation S/W. The former included devices such as a 300 VDC power supplier, Fiber-Optic (F/O) to Ethernet communication converter, and main control PC. The latter was developed using an ROS (Robot Operation System) based on Linux. The basic performance of the manufactured robot platform was verified through a water tank test, where the robot was manually operated using a joystick, and the robot motion and attitude variation that resulted from the manipulator movement were closely observed.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• 제36권4호
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• pp.28-38
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• 2018

The purpose of this study is to clarify what is the unique garden making methods of Enshu Kobori by surveying and analyzing that existing garden of Enshu Kobori is different from the existing Japanese garden that had been built up to such a period. Enshu Kobori breaks away from the conventional frame that was established with the gardens of existing Karesansui style(枯山水樣式) with the materials of rocks and sands. Enshu Kobori is produced to make harmony with the rocks by trimming the Rhododendron indicum and this type of making method of Enshu was originated from the aesthetic principle of kireisabi. Due to this type of cause, the garden of Enshu Kobori displays splendid and yet a simple beauty of gardening. With respect to the establishment of a garden unique to Enshu Kobori as such, it seemed to have the cultural background expanded with the cultural perception and official family class of the edo period where it strived for new things. Therefore, Enshu Kobori was designed as the ornament-oriented garden rather than the garden that requires direct ceremonial act. The subject sites for this study are Raikyuji, Daichiji, Shodenji, Nanzenji Hojo and Konchiin as intended by Enshu Kobori. Contents of the study contemplate the location of garden, factors to introduce the garden, structure of garden, background of garden, use of stones, plants and scenic views to clarify the uniqueness of the Enshu Kobori garden.

• Journal of the Korea institute for structural maintenance and inspection
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• 제26권1호
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• pp.81-88
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• 2022

In the NRC (New paradigm Reinforced Concrete) beam, steel forms, main angles used as main reinforcements, and shear angles used as basic shear reinforcements are welded and assembled in the form of vierendeel truss structures in a steel factory. After the NRC truss frame is installed at the site, additional main reinforcement and shear reinforcement are distributed. In this study, the shear performance evaluation of the NRC beam was conducted through shear tests in accordance with the type of shear reinforcement of the NRC beam (shear angle, inclined shear reinforcing bar, and U-type cover bar). As a result of the test, the initial stiffness was similar before the initial cracking of each specimen, and all specimens were shear fractured.The shear reinforcements of the specimens exhibited a yielding behavior at the time of the maximum sheat force, and the shear strengths of the specimens increased as the amount of reinforcement of the shear reinforcement increased. These results show that NRC shear reinforcements exhibit shear performance corresponding to their shear strength contribution. As a result of calculating the nominal shear strengths according to KDS 14 20 22, the experimental shear strengths of the NRC beam specimens with shear reinforcement was 37~146% larger than the nominal shear strengths, so It was evaluated as a safety side.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제42권5호
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• pp.599-606
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• 2022

Strain gauges and the bridge weigh-in-motion (BWIM) method are the representative field measurement methods used for fatigue evaluationsof a steel bridge-in-service. For a fatigue reliability evaluation to assess fatigue damage accumulation, the effective stress range and the number of stress cycles applied as the fatigue details can be estimated based on the AASHTO Manual for Bridge Evaluations with the field measurement data of the target bridge. However, the procedure for estimating the effective stress range and the stress cycles from field measurement data has not been explicitly presented. Furthermore, studies that quantitatively compare differences in fatigue evaluation results according to the field measurement data type or processing method used are still insufficient. Here, a fatigue reliability evaluation is conducted using strain and BWIM data that are measured simultaneously. A frame model and a shell-solid model were generated to examine the effect of the accuracy of the structural analysis model when using BWIM data. Also, two methods of handling BWIM data when estimating the effective stress range and average daily cycles are defined. As a result, differences in evaluation results according to the type of field measurement data used, the accuracy of the structural analysis model, and the data handling method could be quantitatively confirmed.