• Journal of The Korean Astronomical Society
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• v.51 no.6
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• pp.207-214
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• 2018

A coelostat is often used for solar observations, because it corrects the image rotation automatically by guiding sunlight into a fixed telescope with two plane mirrors. For the purposes of education and spectroscopic observation, the solar group at Seoul National University (SNU) plans to develop the SNU coelostat (SNUC) and install it in the SNU Astronomical Observatory (SAO). Requirements of the SNUC are < 1" positioning accuracy with 30 cm beam size on the entrance pupil in the compact dome. To allow for installation in the small dome, we design a compact slope type coelostat with a 45 cm primary plane mirror and a 39 cm secondary plane mirror. The motion of the SNUC is minimized by fixing the position of the slope frame. Numerical simulations of the available observational time of the designed coelostat shows that the sun can be observed ay all times from June to early August and at least three hours in other months. Since the high accuracy driving motors installed in the SNUC can be affected by external environment factors such as humidity and temperature variations, we design a prototype to test the significance of these effects. The prototype consists of a 20 cm primary plane mirror, a 1 m slope rail, a direct drive motor, a ballscrew, a linear motion guide, an AC servo motor, a reduction gear and a linear encoder. We plan to control and test the accuracy of the prototype with varying atmospheric conditions in early 2019. After testing the prototype, the SNUC will be manufactured and installed in SAO by 2020.

• English & American cultural studies
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• v.14 no.1
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• pp.27-51
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• 2014

Doris Lessing describes a band of revolutionaries who become involved in terrorist activities far beyond their level of competence in The Good Terrorist. Alice Mellings who is from a middle-class family has organized a squat house in London and seems capable of controlling everyone around her and anything about the house. She is seemingly like a housekeeper or a breadwinner. She also likes to be on the battlefront, for instance, demonstrating, picketing and spray-painting slogans. Such is able to easily exploit the others and she increasingly becomes the leader in the house. Recently some critics have focused on the political and social roles of the protagonist who represents a voice of terrorists in the 1980s England. Based on this, The Good Terrorist is read with the concept of the subject of feminism that Gillian Rose adopts in order to show that this subject tries to avoid the exclusion of the master subject. This subject imagines spaces which are not structured through masculinist claims to exhaustiveness. Alice as the subject of feminism shows different roles; she extorts or steals money for the maintenance of the house from her affluent parents; she spends all her time cleaning, fixing, decorating the deserted house; and she looks after the official affairs related to the house with her skills and experiences. She is systematically in charge of the house and sits at the head of the table in the kitchen. But when their activities turn into disaster and their plans fail, Alice willingly decides to close down the house after ousting the members. Here in her extorted gaze it is revealed that she takes control over the working class members of the house who are unable to lead a revolution because of their own problems and thereby the working class are dominated by the middle class. That is, the place is paradoxically recreated based on class differences, which the revolutionaries try to break. By representing the deconstruction and recreation of the place through squat houses, Lessing reveals her implicit feminism in which a new place should be produced crossing the principle of the dichotomy of gender and class.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.435-444
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• 2001

WC-( $Ti_{1-x}$ A $l_{x}$) N coatings of constant changing Al concentration were deposited on S45C substrates by high-ionization sputtered PVD method. The Al concentration could be controlled by using evaporation source for Al and fixing the evaporation rate of the metals (i.e, WC- $Ti_{0.86}$A $l_{0.14}$N, WC- $Ti_{0.72}$A $l_{0.28}$N, and WC- $Ti_{0.58}$A $l_{0.42}$N). The corrosion behavior of WC-( $Ti_{1-x}$ A $l_{x}$)N coatings in a deaerated 3.5% NaCl solution was investigated by electrochemical corrosion tests and surface analyses. The measured galvanic corrosion currents between coating and substrate indicated that WC- $Ti_{0.72}$A $l_{0.28}$N coating showed the best resistance of the coating tested. The results of potentiodynamic polarization tests showed that the WC- $Ti_{0.72}$A $l_{0.28}$N coating deposited with 32W/c $m^2$ of Al target revealed higher corrosion resistance. This indicated that the WC- $Ti_{0.72}$A $l_{0.28}$N coating is effective in improving corrosion resistance. In EIS, the WC- $Ti_{0.72}$A $l_{0.28}$N coating showed one time constant loop and increased a polarization resistance of coating ( $R_{coat}$) relative to other samples. Compositional variations of WC-( $Ti_{1-x}$ A $l_{x}$)N coatings were analyzed by EDS and XRD analysis was performed to evaluate the crystal structure and compounds formation behavior. Surface morphologies of the films were observed using SEM and AFM. Scratch test was performed to measure film adhesion strength.strength. adhesion strength.strength.

• Journal of Korea Trade
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• v.27 no.1
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• pp.79-100
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• 2023

Purpose - The purpose of this study is to analyze the market power of the Korea Container Shipping Market (Intra Asia, Korea-Europe, and Korea-U.S.) to verify the existence of collusion empirically, and to answer whether the joint actions of liner market participants in Korea have formed market dominance for each route. Precisely, it will be verified through the Lerner index as to whether the regional market of Asia is a monopoly, oligopoly, or perfect competition. Design/methodology - This study used a Lerner index adjusted with elasticity presented in the New Imperial Organization (NEIO) studies. NEIO refers to a series of empirical studies that estimate parameters to judge market power from industrial data. This study uses B-L empirical models by Bresnahan (1982) and Lau (1982). In addition, NEIO research data statistically contain self-regression and stability problems as price and time series data. A dynamic model following Steen and Salvanes' Error Correction Model was used to solve this problem. Findings - The empirical results are as follows. First, λ, representing market power, is nearly zero in all three markets. Second, the Korean shipping market shows low demand elasticity on average. Nevertheless, the markup is low, a characteristic that is difficult to see in other industries. Third, the Korean shipping market generally remains close to perfect competition from 2014 to 2022, but extreme market power appears in a specific period, such as COVID-19. Fourth, there was no market power in the Intra Asia market from 2008 to 2014. Originality/value - Doubts about perfect competition in the liner market continued, but there were few empirical cases. This paper confirmed that the Korea liner market is a perfect competition market. This paper is the first to implement dynamics using ECM and recursive regression to demonstrate market power in the Korean liner market by dividing the shipping market into Deep Sea and Intra Asia separately. It is also the first to prove the most controversial problems in the current shipping industry numerically and academically.

• Women's Health Nursing
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• v.2 no.2
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• pp.182-201
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• 1996

The purpose of this study is to examine a married nurse's experience of child rearing through being applied to phenomenological research method. By exchanging their experiences, helping and understanding one another, married nurses can work with delight considering their own present job as their lifelong job. In addition this study can help single nurses overcome the female crises such as marriage, childbirth, and child rearing they will experience in the future. The subjects of this research was 26 married nurses who work for a university hospital in affiliation in Seoul and have children. The period of materials collection was from Feb. 1st to Mar. 3, 1995. The method of materials collection was primarily to write down a questionary with openhearted contents. In collecting it, the respondents were allowed to say at their pleasure through further interview. The materials were analyzed by Giorgi's phenomenological analysis method. The findings of this study are as follows ; 1) The responses of married nurses' experience of child rearing-[pleasure] [family solidarity] [maternal-infant attachment] [understanding] [toilsome]-were induced. That is, at once affirmative experience and hard experience coexisted. 2) The method of married nurses' child rearing-[rearing politely] [raising understanding] [having the sense of family community] [rearing with praying the heart] [careless]-were induced. 3) The support system of married nurses' child rearing-[having help family] [having help from others]-were induced. According to the above findings, the married nursed showed affirmative responses about their experience of child rearing, but at the same time they expressed painful when stayed apart from their children on account of their job or when their children were sick. In the method of child rearing, they tried to grow their children polite because there was much time for them to stay apart from their children. And they tried to give a better explanation in order that their children can have an independence spirit. They tended to compensate through frequent physical touch with their children. As the support system of married nurses' child rearing, they asked their parents or their parents-in-law to take care of their children, hired a nursery governess in their houses, or used a children's home, if they can't afford to. That is, the only one who has a firm sense of her profession, tries to inspire her accomplishment, and is receiving her husband' love and understanding is considered to perform two things simultaneously with harmony, having an recognition of lifelong job. Suggestions 1. The method to solve mental troubles on child rearing should be groped. 2. Their economical burden should be reduced by establishing children's home in their working places, and the increase of maternal-infant interaction should be contrived. 3. The chance of education should be offered in order that married nurses themselves might inspire self-conceit and professionalism on clinical nursing. 4. The familiar mood should be created through planning the programs to be accompanied with children as an annual event in hospital. 5. The part-time nurse system should be suggested to utilize. 6. The system of circulation working should be converted into the system of fixing working according to the characteristic of each department. 7. Programs for special activities such as learning foreign languages and computer should be supported positively.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.9-14
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• 2021

Recently, magnetic resonance imaging (MRI), which can acquire images with good contrast without exposure to radiation, has been widely used for diagnosis. However, noise that reduces the accuracy of diagnosis is essentially generated when acquiring the MR images, and by adjusting the parameters, the noise problem can be solved to obtain an image with excellent characteristics. Among the parameters, the number of excitation (NEX) can acquire images with excellent characteristics without additional degradation of image characteristics. In contrast, appropriate NEX setting is required since the scan time increases and motion artifacts may occur. Therefore, in this study, after fixing all MRI parameters through the MRiLab simulation program, we tried to evaluate the tendency of image characteristics according to changing NEX through quantitative evaluation of brain T2 weighted images acquired by adjusting only NEX. To evaluate the noise level and similarity of the acquired image, signal to noise ratio (SNR), contrast to noise ratio (CNR), root mean square error (RMSE) and peak signal to noise ratio (PSNR) were calculated. As a result, both noise level and similarity evaluation factors showed improved values as NEX increased, while the increasing width gradually decreased. In conclusion, we demonstrated that an appropriate NEX setting is important because an excessively large NEX does not affect image characteristics improvement and cause motion artifacts due to a long scan.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.31-39
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• 2015

This paper presents the static and kinematic positioning accuracy by the real-time GPS positioning modes of the low-cost GPS receivers using NTRIP-based augmentation service. For this, acquires both the raw measurements data of the field tests by LEA 6T GPS module of u-blox AG, and correction communication via NTRIP caster with RTKLIB as an open source program for GNSS solution. With computing the positions of the check points and road tracks by six kinds of GPS positioning modes which are Single, SBAS, DGPS, PPP, RTK, and TCP/IP_RTK, compared these results to the reference position of the check points. The position error average and rmse of the static test by GPS L1 RTK surveying showed $N=0.002m{\pm}0.001m$, $E=0.004m{\pm}0.001m$ in horizontal plane, and $h=-0.116m{\pm}0.003m$ in vertical, these results are very closed to the coordinates with the geodetic receiver. Especially, in case of the kinematic test with obstacles located on both sides of road, the computed track with ambiguity fixing showed very similar trajectory considerably from VRS network RTK mode. And also, evaluate and verify the performance of the TCP/IP_RTK mode developed based on TCP/IP protocol.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.139-153
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• 2003

The purpose of the study was to present technical guidance about the field goal kicking motion in American football for novices. For this purpose, kinematic analysis on the field goal kicking motion of two skilled players and two unskilled players was carried out. The following conclusions were made: 1. In comparison on the total elapsed time of the kicking, there were no significant differences between two groups. The progressing time from BP event to impact among experts group, however, took 0.141 second less than that of novices group. 2. The experts group showed right hip rotatier horizontally toward the targeted ball fixing left hip as the axis. On the other hand, the novices group didn't use the left hip as the axis in the kicking motion. 3. At the impact of kicking the ball, regarding with the distance of the ball and the supporting leg, the right and left distance of experts was 3.45cm longer than that of novices, the front and the rear distance of experts was 5.14cm shorter than novices. 4. At the impact, experts' initial velocity of the targeted ball was $5.27^m/s$ faster than novices', besides experts' incidence angular displacement was $3.78^{\circ}$ larger than novices'. 5. After BP event, experts showed a stable movement maintaining flexion and extension at left hip joint and knee joint. On the other hand, for novices, the angle of the left lower extremities became larger. 6. Experts showed the efficient flexion and extension of the hip joint and the knee joint during following procedure in the whole event of the kicking motion. At the BP event, the right knee joint angle of novices was $11.46^{\circ}$ larger than that of experts. However, the duration of the impact event and FT event among, novices had less extension of knee joint than experts. 7. At the 2nd phase, for both of the groups, the angular velocity of the knee joint drastically increased as the angular velocity of hip joint decreased. However, only novices showed the largest negative angular velocity at the impact.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.25-30
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• 1998

Time-lapse crosswell seismic data, recorded before and after the cavity filling, showed that the filling increased the velocity at a known cavity zone in an old mine site in Inchon area. The seismic response depicted on the tomogram and in conjunction with the geologic data from drillings imply that the size of the cavity may be either small or filled by debris. In this study, I attempted to evaluate the filling effect by analyzing velocity measured from the time-lapse tomograms. The data acquired by a downhole airgun and 24-channel hydrophone system revealed that there exists measurable amounts of source statics. I presented a methodology to estimate the source statics. The procedure for this method is: 1) examine the source firing-time for each source, and remove the effect of irregular firing time, and 2) estimate the residual statics caused by inaccurate source positioning. This proposed multi-step inversion may reduce high frequency numerical noise and enhance the resolution at the zone of interest. The multi-step inversion with different starting models successfully shows the subtle velocity changes at the small cavity zone. The inversion procedure is: 1) conduct an inversion using regular sized cells, and generate an image of gross velocity structure by applying a 2-D median filter on the resulting tomogram, and 2) construct the starting velocity model by modifying the final velocity model from the first phase. The model was modified so that the zone of interest consists of small-sized grids. The final velocity model developed from the baseline survey was as a starting velocity model on the monitor inversion. Since we expected a velocity change only in the cavity zone, in the monitor inversion, we can significantly reduce the number of model parameters by fixing the model out-side the cavity zone equal to the baseline model.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.76-82
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• 2011

Purpose: Lymphoscintigraphy is absolutely being used standard examination in lymphatic diagnosis, evaluation after treatment, and it is useful for lymphedema to plan therapy. In case of lymphoscintigraphy of lower-extremity lymphedema, it had an effect on results if patients had not pose same position on the examination of 1 min, 1 hour and 2 hours after injection. So we'll study the methods to improve confidence with minimized quantitative analysis errors by influence factors. Materials and Methods: Being used the Infinia of GE Co. we injected $^{99m}Tc$-phytate 37 MBq (1.0 mCi) 4 sylinges into 40 people's feet hypodermically from June to August 2010 in Samsung Medical Center. After we acquired images of fixed and unfixed condition, we confirmed the count values change by attenuation of soft tissue and bone according to different feet position. And we estimated 5 times increasing 2 cm of distance between $^{99m}Tc$ point source and detector each time to check counts difference according to distance change by different feet position. Finally, we compared 1 and 6 min lymphoscintigraphy images with same position to check the effect of quantitative analysis results owing to difference of amounts of movement of the $^{99m}Tc$-phytate in the lymphatic duct. Results: Percentage difference regarding error values showed minimum 2.7% and maximum 25.8% when comparing fixed and unfixed feet position of lymphoscintigraphy examination at 1 min after injection. And count values according to distance were 173,661 (2 cm), 172,095 (4 cm), 170,996 (6 cm), 167,677 (8 cm), 169,208 counts (10 cm) which distance was increased interval of 2 cm and basal value was mean 176,587 counts, and percentage difference values were not over 2.5% such as 1.27, 1.79, 2.04, 2.42, 2.35%. Also, Assessment results about amounts of movement in lymphatic duct within 6 min until scanning after injection showed minimum 0.15%, and maximum 2.3% which were amounts of movement. We can recognize that error values represent over 20% due to only attenuation of soft tissue and bone except for distance difference (2.42%) and amounts of movement in lymphatic duct (2.3%). Conclusion: It was show that if same patients posed different feet position on the examination of 1 min, 1 hour and 2 hours after injection in the lymphoscintigraphy which is evaluating lymphatic flow of patients with lymphedema and analyzing amount of intake by lymphatic system, maximum error value represented 25.8% due to attenuation of soft tissue and bone, and PASW (Predictive Analytics Software) showed that fixed and unfixed feet position was different each other. And difference of distance between detector and feet and change of count values by difference of examination beginning time after injection influence on quantitative analysis results partially. Therefore, we'll make an effort to fix feet position and make the most of fixing board in lymphoscintigraphy with quantitative analysis.