• The KSFM Journal of Fluid Machinery
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• v.4 no.1 s.10
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• pp.7-13
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• 2001

In developing a multistage compressor, the stage matching is one of the critical design issues. The mismatching can be often observed even if each stage has been proven good and then used as part of a compression system. A good matching among the stages can be achieved by changing various design parameters (i.e., passage cross sectional areas, blades angles, stagger angles, curvature, solidity, etc.). Therefore, designers need to find out what parameters must be changed and how much. In this study, a method to search the design parameters for optimum stage matching has been used based on an 1-D mathematical model of a compressor, which uses the data obtained from the preliminary test to identify the design parameters. This methodology is applied with a two-stage axial compressor, which was originally designed for a helicopter gas turbine engine. After identifying design parameters using preliminary test data, an optimization process has been employed to achieve the best matching between the stages (i.e., maximum efficiency of the compressor at its operation modes within a given range of the rotor speed under given restrictions for required stall margins and mass flow). 3-D flow calculations have been performed to confirm the usefulness of the corrections based on the 1-D mathematical model. Calculational results agree well with the experimental data in view of the performance characteristics. Some promising results were produced through the methodology proposed in this paper in conjunction with flow calculations.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.179-187
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• 2010

For the user-centered interior space design, a designer needs to carefully focus on the details from which the user must keenly observe or concentrate on the space and how to deliberately check the image of the space. Following this view, for the user-centered interior space design this study analyzes the way which the space is represented from the perspective of the image assessment. The results obtained from this study are summarized as follows: First, this study analyzed the characteristic of space image change in the form of cross-comparison between one space and a rotated space. With analyzing of an eye fixation by showing the space, the space images of "concentration-dispersion" and "strengthening-weaken "have an important role in the analysis of the perception of space. it confirmed that the method of space perception was changed by rotated the space. Second, With changing quantities of image and extraction of deviation from adjective in survey, it quantitatively graps that respondents of feel in space perception by changing the space and "concentration" and 'dispersion" for process of space choice. The results of the research can provide important basis to judge the changing of space perception by visual perception. Third, through the analysis of image change rate and deviation rate, the characteristics of image change with space change can be analyzed. The results derived from the study provide the evidence to support the image change by space rotating.

• Journal of Advanced Navigation Technology
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• v.20 no.2
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• pp.134-140
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• 2016

This paper analyzed flight trajectory characteristics of ballistic missiles considering effects of drag forces. It is difficult to intercept ballistic missiles which fly over atmosphere with supersonic speeds and small radar cross section (RCS). In particular, the velocities in the phases of boost and terminal are changed significantly due to the steep variation of the drag force. Therefore, in order to build up a successful ballistic missile defense systems, the effects of the drag forces should be considered in the analysis of ballistic missile trajectory characteristics. In this point of view, this work analyzed the effects of drag forces and derived the flight trajectory characteristics of Scud B, C and Nodong missiles. Model of the ballistic missile flight trajectory is considered the effects of Coriolis and centrifugal forces, and specifications of the missiles are open sources.

• International Journal of Costume and Fashion
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• v.5 no.1
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• pp.1-13
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• 2005

Two hundreds of female aged 19 years old and up were recruited to evaluate the postural changes and bilateral variation of asymmetry over age. To find out the differences among the age group, subjects were classified into 5 groups, early young age(19-29), late young age(30-39), early middle age(40-49), late middle age(50-59), and old age(60-). 35 body measurements were taken by the 3-D body scanner which allowed us to take measurements which cannot be measured using traditional methods, including the shape of a cross section, slice area surface are, and volume. Bilateral variations were observed as a function of age; Depth of scapular point level, scapular point to center back, and blade angle. Postural change of anterior cervical angle, upper anterior thoracic angle, upper posterior thoracic angle, posterior cervical angle, and center back/center front ratio were also exhibited. In each measurements, subjects were classified into normal, and abnormal group. Percentiles of abnormal in shoulder line angle, blade angle, neck point $\∼$ acromial point $\∼$ scapular point, posterior cervical angle, and upper posterior thoracic angle were increased over age group. The upper body of lateral view was classified into 3 types of posture based on the previous research; straight, erect(leaning back), and stooped(bent forward). The percentiles of subjects who have straight postures were decreased as a function of age, but those of stooped postures were increased. Subjects who have erect postures did not so. The stooped posture group shows the big cervical fossa angle, anterior cervical angle, posterior cervical angle, upper posterior thoracic angle, and the small upper anterior thoracic angle comparing to the straight and erect posture group. These results could be apply for clothing construction reflecting the changes in back, shoulder, neck, and the bilateral asymmetry according to the target age group.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.9 no.1
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• pp.15-19
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• 2013

The auxiliary feedwater is an important to remove the heat from the reactor core when the main feedwater system is unavailable. In most initiating events in Probabilistic Safety Assessment(PSA), the operaton of this system is required to mitigate the accidents. For one of domestic nuclear power plants, a design change of a turbine-driven auxiliary feedwater pump(TD-AFWP), pipe, and valves in the auxiliary system is implemented due to the aging related deterioration by long time operation. This change includes the replacement of the TD-AFWP, the relocation of some valves for improving the system availability, a new cross-tie line, and the installation of manual valves for maintenance. The design modification affects the PSA because the system is critical to mitigate the accidents. In this paper, the safety effect of the change of the auxiliary feedwater system is assessed with regard to the PSA view point. The results demonstrate that this change can supply the auxiliary feedwater from the TD-AFWP in the accident with the motor-driven auxiliary feedwater pump(MD-AFWP) unavailable due to test or maintenance. In addition, the change of MOV's normal position from "close" to "open" can deliver the water to steam generator in the loss of offsite power(LOOP) event. Therefore, it is confirmed that the design change of the auxiliary feedwater system reduces the total core damage frequency(CDF).

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.463-470
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• 2015

When a camera installed on a vehicle is used, estimation of the camera pose including tilt, roll, and pan angle with respect to the world coordinate system is important to associate camera coordinates with world coordinates. Previous approaches using huge calibration patterns have the disadvantage that the calibration patterns are costly to make and install. And, previous approaches exploiting multiple vanishing points detected in a single image are not suitable for automotive applications as a scene where multiple vanishing points can be captured by a front camera is hard to find in our daily environment. This paper proposes a camera pose estimation method. It collects multiple images of lane markings while changing the horizontal angle with respect to the markings. One vanishing point, the cross point of the left and right lane marking, is detected in each image, and vanishing line is estimated based on the detected vanishing points. Finally, camera pose is estimated from the vanishing line. The proposed method is based on the fact that planar motion does not change the vanishing line of the plane and the normal vector of the plane can be estimated by the vanishing line. Experiments with large and small tilt and roll angle show that the proposed method outputs accurate estimation results respectively. It is verified by checking the lane markings are up right in the bird's eye view image when the pan angle is compensated.

• Applied Microscopy
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• v.31 no.4
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• pp.315-323
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• 2001

In situ TEM heating experiments utilizing kaolinite powder samples result in the following facts. (1) The water recirculation system adopted in the Gatan's heating holder is required to prevent specimen drift above $500^{\circ}C$. (2) Since the degree of phase changes depends on the thickness of powders below $600^{\circ}C$, examinations of both thin and thick specimens are required. (3) Sample preparation using Mo-grids is required for TEM heating experiments above $900^{\circ}C$. At these temperature ranges the effect of heating rate and holding time on the phase transition process increases drastically, so that a programmed temperature control is required. (4) TEM heating experiments of the embedded powders by epoxy for the cross-sectional view was limited due to the severe epoxy movement during heating above $300^{\circ}C$. Better methods of sample preparation are required to overcome this problem.

• The Journal of the Korea Contents Association
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• v.17 no.8
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• pp.560-569
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• 2017

This study was a cross-sectional study done to determine the relevance and impact factors of gender role attitude and self-esteem on attitude toward homosexuality among college students. A survey was conducted 201 college students with self-report questionnaire in one university of Ulsan. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation, and linear multiple regression with SPSS/WIN(21.0). Factors affecting attitude toward homosexuality included gender, former middle${\cdot}$high schools. Attitude toward homosexuality had a negative correlation with gender role attitude. And gender and gender role attitude accounted for 31.0% of the variance in attitude toward homosexuality. The major factors influencing attitude toward homosexuality were gender and gender role attitude. The more males than females and the more traditional gender role attitude were more negative toward homosexuality. Therefore, it is necessary to provide education program and establish a service program according to gender in order to develope and accept healthy identity of college students for the positive view on homosexuality.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.464-486
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• 2008

Purpose. Electronic intermediaries (e-intermediaries) are gaining significance in international marketing with the rapid development of e-commerce. The goal of this study is to explain empirically what leads to a higher use of this relatively new exportation alternative. Relying on a resource-based view as our research foundation, we focus on information technology (IT) and non-IT factors as possible determinants. Further, this study brings arguments offered by transaction cost theorists to explain the other non-IT determinants. Methodology/Approach. Data are collected from small and medium-sized enterprises (SMEs) in the electronic industry in Korea and the U.S to ensure generalizability. Ordinary least square (OLS) regression is utilized to analyze the data. Findings. This study raises new issues regarding a relatively new type of exporting channel, e-intermediary. Exporting is regarded as the most appropriate strategy for SMEs in international commerce. A number of SMEs stay away from exporting due to limited resources or lack of knowledge regarding foreign markets. The findings in this study should help SMEs use e-intermediaries more widely by developing appropriate IT-related resources (IT-related human and relationship assets) and dealing with non-IT factors (international competence, environmental uncertainty, and duration of relationship) effectively. Originality/Value/Contribution. This study illustrates the significant role of e-intermediaries, which may help SMEs to penetrate the global market effectively. Finding relevant sources in the global e-marketplace is a challenge for non-experienced users like SMEs. This study proposes e-intermediaries as an effective alternative for them. Another contribution of this study is to show how the use of indirect exporting channels, e-intermediaries, decrease costs in exporting transactions. This study suggests an e-intermediary as a hybrid exporting channel to balance risk and profit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.219-226
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• 2012

We investigated the performance of a visible light communication (VLC) transceiver applicable to both of illumination and wireless communication. we considered the visibility of VLC, the easy connection for wireless communication and high-speed transmission and implemented VLC transceiver based on edge-emitting laser diode and silicon photodiode. The proposed VLC transceiver is designated to operate in a full duplex mode at high speed of 120 Mbit/s. The shielding method that is employed as a means to reduce the light cross coupling effect inside the VLC transceiver is proposed and its performance is experimentally measured. We also applied optical antenna to have the larger angle of field of view (FOV) to novel structure of VLC transceiver and examined and analyzed their bit error rate performance, photometric result with respect to the transmission distance, the coverage range and the tilt degree as transmission link characteristic between two transceivers without optical antenna and with optical antenna.