• MALSORI
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• no.37
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• pp.73-85
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• 1999

The prosodic characteristics of Korean particles in read speech were examined in this paper based on K-ToBI labeling system in order to see whether they are prosodically weak form like functions words in English. Acoustic measurements and statistical analysis were done focusing on the distribution of particles over a variety of prosodic positions, prosodic positional effects on the phonetic realization of particles, and acoustic strength of particles compared to those of their surrounding syllables. The panicles were distributed rather equally over all 4 prosodic positions with the highest frequency at IP-medial/AP-final position and the lowest at IP-medial/AP-medial position except that topic marker 'Un/nUn' showed preference for IP-final/AP-final position. There was a significant prosodic positional effect on the duration and F0 of the particles. Duration was the longest at IP-final/AP-final position and interestingly, at IP-medial/AP-medial position while F0 was the highest at IP-final/AP-medial Position as expected. The comparison of the acoustic properties of the particles with those of neighbor syllables showed that duration was generally significantly longer and energy also showed larger values, if not significant, in particles suggesting that the particles in Korean are not prosodically weaker like function words in English.

• Journal of the Optical Society of Korea
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• v.17 no.3
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• pp.262-268
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• 2013

We study the focusing properties of a two-dimensional square-lattice photonic crystal (PC) comprising silica and germanium partitioned cylinders in air background. The finite difference time domain (FDTD) method with periodic boundary condition is utilized to calculate the dispersion band diagram and the FDTD method incorporating the perfectly matched layer boundary condition is employed to simulate the image formation. In contrast to the common square PCs in which the negative refraction effect occurs in the first photonic band without negative phase propagation, in our suggested model system, the frequency with negative refraction exists in the second band and in near-infrared region. In this case, the wave propagates with a negative phase velocity and the evanescent waves can be supported. We also discuss the dependency of the image resolution and its location on surface termination, source location, and slab thickness. According to the simulation results, spatial resolution of the proposed PC lens is below the radiation wavelength.

• The Research Journal of the Costume Culture
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• v.9 no.6
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• pp.818-829
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• 2001

The purposes of this study were to segment the men in twenties and thirties according to clothing benefits sought, and to develop a profile of each segment concerning shopping orientation, self·image, and importance of store attributes. The questionnaire was administered to men in twenties and thirties living in Seoul and data were analyzed by frequency, percentage, factor analysis, cluster analysis, and MANOVA(multivarite analysis of variance). By cluster analysis of clothing benefits sought, three groups were identified and labeled as: (1) the group of focusing the influence of other people and comfort clothing(31.7%): (2) the group of pursuing the fashion trend (48.1%); the group of pursuing the individuality(20.1%). Three groups were then compared through MANOVA on shopping orientation, importance of store attributes, and self-image. Significant differences were found among three groups on three variables. In general, the group of focusing the influence of other people and comfort clothing tended to be ostentatious and tended to wear comfortable clothing. The group of pursuing the fashion trend didn't show specific shopping orientation and just liked to follow the current fashion trend. The group of pursuing the individuality enjoyed the shopping and liked to buy the clothing which enhances the personal character.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.5
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• pp.741-749
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• 2001

An inhomogeneous hyperbolic electric field is established among two-dimensional quadrupole electrodes to which an ac voltage is applied. Conditions under which charged particles are focused into a narrow axis region of the plug laminar flow are discussed. The aerodynamic forces influence the behavior of the charged particles in the quadrupole electric field. We derived the dimensionless equations of motion of a charged particle in the alternating quadrupole electric field, and discussed particle trajectories and focusing performance in terms of two dimensionless parameters, which are functions of particle size, operating pressure, and the amplitude and frequency of applied AC voltage, with the results of numerical simulations and experiments.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.190-194
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• 2005

There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile camera phones. However, conventional magnetic coils of electromagnetic motors are a major obstacle for miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM (ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 1.52 mm/s at 10 kHz input signal in 5 V.

• Transactions of the Society of Information Storage Systems
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• v.2 no.4
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• pp.251-256
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• 2006

There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile phone cameras. However, the magnetic coils used in conventional electromagnetic motors are a major obstacle for the miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM(ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 5.4 mm/s at 10V saw signal of 41 kHz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.620-628
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• 2005

Spatial control of sound is essential to deliver better sound to the listener's position in space. As it can be experienced in many listening environments, the quality of sound can not be manifested over every position in a hall. This motivates us to control sound in a region we select. The primary focus of the developed method has to do with the brightness and contrast of acoustic image in space. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to make two different kinds of zone - the zone of quiet and the zone of loud sound - at the same time. The other perspective of this study is on the direction of sound. It is shown that we can control the direction of perceived sound source by focusing acoustic energy in wavenumber domain. To begin with, the proposed approaches are formulated for pure-tone case. Then the control methods are extended to a more general case, where the excitation signal has broadband spectrum. In order to control the broadband signal in time domain, an inverse filter design problem is defined and solved in frequency domain. Numerical and experimental results obtained in various conditions certainly validate that the acoustic brightness, acoustic contrast, direction of wave front can be manipulated for some finite region in space and time.

• Journal of Oriental Neuropsychiatry
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• v.29 no.4
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• pp.231-238
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• 2018

Objectives: To evaluate the psychological characteristics of Korean medical students focusing on the Holland types and the MMPI-2. Methods: A survey was conducted on 81 Korean medicine students to investigate psychological characteristics focusing on the Holland types and the MMPI-2. Results: The orders of frequency of the Holland type in Korean medicine students were S>I>C>A=E>R (all), I>S>C>R=E>A (male) and S>A>C>I>E>R (female). The relationships between the Holland types and the MMPI-2 were R type (Mf negative), A type (Mf Pa Ma positive, Si negative), S type (Mf positive, D Pt Sc Si negative) and E type (Ma positive, D Si negative). Conclusions: From personality tests for male and female Korean medical students, there were differences on some scales of the Holland types. The Holland types are related to the specific scales of the MMPI-2.

• The Journal of Economics, Marketing and Management
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• v.8 no.4
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• pp.37-45
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• 2020

Purpose: This study aims to clarify the concept of entrepreneurial leadership by reviewing the relevant existing studies, and to examine changes in entrepreneurial leadership research through review and statistical analysis on the articles published in Korean and international journals. Research Design, Data, and Methodology: Among the papers published between 2010 and 2020, 8 Korean studies and 42 international studies (UK and US) that clearly identify entrepreneurial leadership as research topic were analyzed. Results: Examinations on the yearly trends, keywords, and research methods reveal that research on entrepreneurial leadership is increasing recently with the emphasis on the statistical analysis. Keyword analysis shows high frequency of team and innovation for domestic research, while overseas research focuses on entrepreneurship, leadership, and gender associated keywords. Conclusions: This study has confirmed that overseas studies employ various methodologies, focusing on statistical analysis and that the effect of entrepreneurial leadership are in progress. For domestic cases, studies on entrepreneurial leadership are limited in number. Research topics and methods are areas that need further improvements. Research on entrepreneurial leadership has recently begun, requiring diversity in the subjects and methods for future development

• Journal of Technologic Dentistry
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• v.44 no.3
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• pp.104-110
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• 2022

Purpose: This study analyzes the difficulty and discrimination of the paper-based test (PBT) and the computer-based test (CBT) according to item response theory, focusing on the National Dental Technician Examination. Methods: A mock test was conducted from September 15 to 23, 2020, and the final 179 (1 out of 180 absentees)people were the subjects of this study. Both frequency analysis and factor analysis were performed. The collected data were analyzed using IBM SPSS Statistics ver. 18.0 (IBM) and jMetrik programs. The significance level was set to 0.05. Results: The difficulty of the mock test was more easily responded to in CBT. It was also predicted that the CBT could better measure the ability of test takers than the PBT could. Conclusion: The difficulty, discrimination, and reliability of the questions were not affected by the examination method through the mock test. The feasibility of a future change to the CBT was confirmed by the National Dental Technician Examination.