• Magazine of korean Tunnelling and Underground Space Association
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• v.1 no.1
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• pp.81-87
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• 1999

Effects of blasting vibrations on curing concrete have not been well studied. As a result, unrealistic and costly blasting vibration constraints have been placed on blasting when it occurs in the vicinity of curing concrete. To study the effects of blasting, concrete blocks of $30\times20\times20cm$ were molded and placed on the quarry Different sets of concrete blocks were subjected to peak vibrations of 0.25, 0.5, 1.0, 5.0, and 10cm/sec. The impulses of blasting vibrations were applied at thirty minutes intervals . Along with unvibrated concrete blocks, the vibrated concrete samples with 60.3mm in diameters were measured for elastic moduli, sonic velocity and uniaxial compressive strength. Test results can be summarized as follows : 1) The blasting vibrations between 6 and 8 hours after pour generally have exerted bad influences on the uniaxial compressive strength of the concrete 2) Under low vibration of 0.25cm/sec variations of the uniaxial compressive strength were not shown. As the magnitudes of blasting vibration increased, compressive strength of concrete decreased. But under the vibrations between 5 and 10cm/sec decreases in strength were almost same. 3) Physical properties of the p-wave velocity, Young's modulus, and Poisson's ratio appeared to decrease for the concrete blocks subjected to vibration for 6 to 8 hours.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.84-90
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• 2004

A performance evaluation is made in terms of thrust, impulse bit. and specific impulses for a set of mono-propellant hydrazine thrusters producing 0.95 lbf of nominal thrust at an inlet pressure of 350 psia. With a brief description on the hot-firing test configuration and procedures. a typical data obtained from steady-state firing mode is given directly showing the variational behavior of propellant supply pressure, mass flow rate, vacuum condition, and thrust. The performance features are successfully compared to the reference criteria of 1-lbf standard mono-propellant rocket engine. Additionally. a statistical inter-thruster treatment is concisely depicted for the justification of selected thrusters as a grouped member of flight model for spacecraft propulsion system.

• English Language & Literature Teaching
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• v.9 no.1
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• pp.205-225
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• 2003

This study attempts to survey the moral growth through prison motif. Malamud deals with the theme of suffering deeply. To learn love accompanied by suffering is the way to be moral and therefore suffering becomes Malamud's main concern. The hardship from suffering and love by trial leads Frank and Yakov to guest of selves. Through this their erotic impulses are changed into caritas. Malamud portrays Frank as a schlemiel. Like Malamud's other heroes he is also born to suffering, conditioned by it, and ultimately finds the meaning of his life in learning to deal with it. At last he carries the burden of supporting Helen and Ida. As a result, Frank becomes a social failure but a moral success as traditional American Adam. The prison motif is a rather strong function of setting symbolism in The Fixer. Yakov is imprisoned for a heinous crime that he did not commit. Yakov experiences hard physical and spiritual pains in prison for two and half years. His bitter suffering has matured him, changed him into a man with love, sacrifice and responsibility for others. At last he returns a true Jew and good man with perfect spirit.

• Research in Community and Public Health Nursing
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• v.28 no.2
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• pp.118-128
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• 2017

Purpose: The purpose of this study is to measure health-related quality of life (HRQoL) and to investigate the affecting factors according to gender in older adults by using the 2012 Korea Health Panel data. Methods: The Korea Health Panel data 2012 were collected from February to August 2012 by Korea Institute for Health and Social Affairs and National Health Insurance Corporation and the number of respondents were 1,921. The data were analyzed by t-test, chi-square, Pearson correlation coefficient and multiple regression using SPSS/WIN program. Results: The limitation of activity was the most influential factor for health-related quality of life of both male and female. For male, the affecting factors on HRQoL were hearing problems and frustration. For female, the affecting factors on HRQoL were eating problems, depression and suicidal impulses. Drinking, moderate physical activities, vision problems and stress had a significant effect on HRQoL for both male and female. Conclusion: Health care providers should consider the differences between male and female when they design a program in order to improve HRQoL of older people.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.4
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• pp.311-318
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• 2020

This study investigates the performance and blade airloads for a rigid coaxial rotor of high-speed compound unmanned rotorcrafts. The present compound unmanned rotorcraft uses not only a rigid coaxial rotor, but also wings and propellers for high-speed flights. For the rigid coaxial rotor in this work, CAMRAD II, a rotorcraft comprehensive analysis code, is used to study the performance at a flight speed of up to 250 knots and blade section lift forces at 230 knots. As the flight speed increases, the rotor power decreases; however, the power of propellers increases to overcome the drag force of a rotorcraft in high-speed flight. The effective lift-to-drag ratio of a rotor has the maximum value of about 11.6 which is much higher than the value of the conventional helicopter. The blade section lift forces of the upper and lower rotors at 230 knots show the similar variation trends for one rotor revolution, and the impulses because of the aerodynamic interaction between both rotors are observed.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1326-1336
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• 2018

This paper proposes a numerical approach to predict the critical flashover voltages of air gaps under lightning impulses. For an air gap, the impulse voltage waveform features and electric field features are defined to characterize its energy storage status before the initiation of breakdown. These features are taken as the input parameters of the predictive model established by support vector machine (SVM). Given an applied voltage range, the golden section search method is used to compute the prediction results efficiently. This method was applied to predict the critical flashover voltages of rod-rod, rod-plane and sphere-plane gaps over a wide range of gap lengths and impulse voltage waveshapes. The predicted results coincide well with the experimental data, with the same trends and acceptable errors. The mean absolute percentage errors of 6 groups of test samples are within 4.6%, which demonstrates the validity and accuracy of the predictive model. This method provides an effectual way to obtain the critical flashover voltage and might be helpful to estimate the safe clearances of air gaps for insulation design.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.239-246
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• 2019

Teenagers in multicultural families are more prone to depression and problem behaviors caused by violence such as bullying in schools due to their appearance, language presentation skills, and poor learning abilities compared to teenagers in general families. This study is meaningful in that it provides basic information for prevention measures in intervening with damage caused by school violence such as depression, anxiety, suicidal impulses and emotional and social. For this purpose, a survey of 300 elementary school students from 4 to 6 grade, junior high school, and high school students was conducted. A total of 400 questionnaires were distributed and of thos e 385 were used for the final analysis. The results of the study are as follows. First, the psychological factors of suicidal ideation were higher in the victimized group than school violence. Second, there was a significant difference in the relationship between emotional - social isolation and school violence experience. Third, there was a significant difference in the relationship between experience of suicide ideation and depression as well as anxiety of emotional - social isolation with psychological maladjustment. In conclusion, we plan to find ways to stabilize the multicultural society by providing prevention and protection measures against school violence.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.95-101
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• 2007

Recently, two phase scheme for removing impulse noise in images is proposed. This algorithms first detect the noise candidates based on the adaptive median filter, and then apply optimizing techniques recursively only to those noise candidates to restore image. Thus the noise detector with high accuracy is important role on this algorithm, In this paper, novel noise detector is proposed, which can detect impose noise with high accuracy while reducing the probability of false detecting image details as impulses. And the method for reducing computational cost of regularization phase is presented also.

• English & American cultural studies
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• v.14 no.1
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• pp.287-310
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• 2014

While Janis Joplin is generally known as a hippie rock star of an untimely death to Korean audience, she is more strongly evoked in the image of blues mama in American context. Blues, definitely based on African-American vernacular tradition, is defined as a matrix, which is "a point of ceaseless input and output, a web of intersecting, crisscrossing impulses always in productive transit," to borrow Houston A. Baker's expression. This article explores how her life and music can be understood in blues tradition, especially in terms of personal and social transgression for which she was criticized, focusing on her blues performance. First of all, born and growing up in southern Texas between 1940s and 1960s, she expressed her innate suspicion against segregation and white supremacy, actively embracing rich black musical heritage of the area. Second, against the normative social and moral expectation of a middle class white woman to be a suburban housewife, she sought her own desire, whether it was professional ambition or sexual possibility. Third, beyond the selling image of a heterosexually lascivious blues mama, she dared to be a homosexual and bisexual, while it was not publically acknowledged. Along with her alcohol and drug dependence, such transgressions against normative social expectation were not made without her inner conflict, leaving a trace of trauma, hesitation, and the blues. While she was "buried alive in the blues," as a sacrifice at the altar of the 1960s, she still remains "alive" provoking "fire inside of everyone of us."