• The Korean Journal of Applied Statistics
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• v.35 no.2
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• pp.189-201
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• 2022

In this study, we propose factor augmentation to improve forecasting power of cryptocurrency return. We consider financial and economic variables as well as psychological aspect for possible factors. To be more specific, financial and economic factors are obtained by applying principal factor analysis. Psychological factor is summarized by news sentiment analysis. We also visualize such factors through impulse response analysis. In the modeling perspective, we consider ARIMAX as the classical model, and random forest and deep learning to accommodate nonlinear features. As a result, we show that factor augmentation reduces prediction error and the GRU performed the best amongst all models considered.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.47-59
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• 2022

Liquid hydrogen/liquid oxygen rocket engines with highest specific impulse have been developed since the 1950s and used until now to maximize the capability of space launch vehicles. Domestic liquid hydrogen infrastructures for the production, transportation and distribution are being expanded at world-class level with the rise of hydrogen economy, which is a great opportunity for the performance enhancement for indigenous space launch vehicles. In this paper, feasibility of applying liquid hydrogen as a propellant is investigated in various aspects. The status of domestic liquid hydrogen infrastructure, the technologies required for liquid hydrogen engines, and operational aspects for safe handling of hydrogen are reviewed. In addition, test facilities for developing hydrogen engines are introduced briefly.

• Journal of Audiology & Otology
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• v.23 no.2
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• pp.103-111
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• 2019

Background and Objectives: Dizzy patients with abnormal otolith function tests, despite a normal caloric response, are defined as having specific (isolated) otolith organ dysfunction. This study was performed to compare the differences in clinical presentation between isolated otolith dysfunction (iOD) patients with lab- and Sx-based iOD group and lab-based iOD symptoms. Subjects and Methods: The medical records of 23 iOD patients with normal caloric response but abnormal cervical vestibular evoked myogenic potential (VEMP), ocular VEMP, or subjective visual vertical were reviewed. Non-spinning vertigo was considered as otolith-related symptoms. The patients' age, onset of dizziness, Numeric Rating Scale on the severity of dizziness, and concomitant vestibular disorders were analyzed. Results: Patients in the lab-based iOD group were significantly older than those in the lab- and Sx-based iOD group. Known vestibular disorders were significantly more common in the lab-based iOD group (83.3%) compared to the lab- and Sx-based iOD group (18.2%). Despite the normal caloric response, catch-up saccade was found in the video head impulse test in more than half (54.5%) of the lab-based iOD group patients. There was no catch-up saccade in the lab- and Sx-based iOD group. There were no significant differences in gender ratio, frequency of dizziness attacks, and duration of illness. Conclusions: We propose new definitions of definite iOD (lab- and Sx-based iOD) and probable iOD (lab- or Sx-based iOD). These new definitions may help researchers to identify patients who are more likely to have true iOD, and facilitate comparisons of results between different studies.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.6
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• pp.86-100
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• 2022

In this paper, the concept and characteristics of the nuclear propulsion system were introduced and the state of the art for the nuclear-powered space propulsion in abroad were summarized. Since uranium used in nuclear propulsion has a very high energy density per unit mass, it has exceptional specific impulse performance compared to the existing chemical propulsion method and can reduce the amount of fuel loaded, thereby having advantage for long-distance exploration. For this reason, advanced countries in space development are recently spurring to the research of nuclear propulsion technology, and it is judged that the development of a propulsion engine using nuclear power is absolutely necessary in order to gain an competitive edge on the space development.

• Korean Journal of Audiology
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• v.23 no.2
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• pp.103-111
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• 2019

Background and Objectives: Dizzy patients with abnormal otolith function tests, despite a normal caloric response, are defined as having specific (isolated) otolith organ dysfunction. This study was performed to compare the differences in clinical presentation between isolated otolith dysfunction (iOD) patients with lab- and Sx-based iOD group and lab-based iOD symptoms. Subjects and Methods: The medical records of 23 iOD patients with normal caloric response but abnormal cervical vestibular evoked myogenic potential (VEMP), ocular VEMP, or subjective visual vertical were reviewed. Non-spinning vertigo was considered as otolith-related symptoms. The patients' age, onset of dizziness, Numeric Rating Scale on the severity of dizziness, and concomitant vestibular disorders were analyzed. Results: Patients in the lab-based iOD group were significantly older than those in the lab- and Sx-based iOD group. Known vestibular disorders were significantly more common in the lab-based iOD group (83.3%) compared to the lab- and Sx-based iOD group (18.2%). Despite the normal caloric response, catch-up saccade was found in the video head impulse test in more than half (54.5%) of the lab-based iOD group patients. There was no catch-up saccade in the lab- and Sx-based iOD group. There were no significant differences in gender ratio, frequency of dizziness attacks, and duration of illness. Conclusions: We propose new definitions of definite iOD (lab- and Sx-based iOD) and probable iOD (lab- or Sx-based iOD). These new definitions may help researchers to identify patients who are more likely to have true iOD, and facilitate comparisons of results between different studies.

• Research in Community and Public Health Nursing
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• v.12 no.3
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• pp.755-772
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• 2001

The specific purpose of this study was as follows: 1) To identify the level of sexual awareness and demand for sex education of teenagers, their parents and teachers. 2) To investigate the attitude toward and acceptance of heterosexual friendships by teenagers, their parents and teachers. 3) To identify the experience and direction of sex education of parents and teachers. For this purpose, this study selected 341 male and female teenagers at three high schools located in a city, 119 parents with high school students and 243 elementary/middle/high school teachers. The structured questionnaire was distributed to each of them and returned by them. This study was conducted over the period between June 1. 2001 and Aug 31. 2001. A total of 720 questionnaires were distributed to them and 703 were returned. Data analysis was conducted to obtain percentage and frequency using the SAS program. As a result, the following findings were obtained: Parents and teachers showed a similar attitude about sexual awareness, but teenagers showed a different attitude. In terms of the level of feeling of and interest in 'sex', teenagers, parents and teachers were comfortable in accepting it. As for sexual curiosity in puberty, 84.8% of the parents and 95.5% of the teachers responded that it was natural, whereas only 14.7% of teenagers responded that it was natural. But As for the item that 'sex is natural as one of human needs', 3.6% of the teenagers, 16.8% of the parents and only 1.2% of the teachers responded that it was not. As for the item that 'A man has a stronger sexual impulse than a woman', 6.1% of the teenagers, 16.8% of the parents and 17.3% of the teachers responded that it was not. 64.2% of the teenagers and 90.2% of the teachers responded that it was impossible to overcome the sexual impulse, whereas only 8.4% of the parents responded that it was possible. As for the item of masturbation, 64.5% of the teenagers responded that it was possible for male students and not possible for female students. 67.2% of the parents and 91.1% of the teachers responded that it was possible regardless of sex. As for the item of an attitude toward virginal purity, both the parents and teachers showed that virginal purity was important for both man and woman, but teenagers showed a weak awareness of virginal purity. As for the item, 'It is possible to have sexual intercourse with a lover during adolescence', 20.2% of the teenagers, 79% of the parents and 87.7% of the teachers responded that it was impossible. As for the item 'It is necessary to keep premarital virginal purity for a happy married life', 21.1% of the teenagers, 74.8% of the parents and 55.1% of the teachers responded that it was necessary, which shows that teenagers had a different opinion than parents and teachers. In case of pregnancy in adolescence, most of the responding teenagers, parents and teachers chose abortion. As for the item 'female refusal on male sexual approach', respondents accepted female refusal as they did for orders of teachers, parents and adolescents. As for item 'An assaulter is entirely to blame for sexual assault', all of three groups responded in the affirmative.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.299-304
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• 2013

The HAN which is an ionic liquid is a non-toxic monopropellant with high storability, and its specific impulse can be increased by blending methanol, thereby it can substitute the hydrazine. The HAN was synthesized by acid-base reaction of hydroxylamine and nitric acid, and the blending ratio of HAN and methanol is 8.2:1. The iridium catalyst was used to decompose the HAN, and 1 N class thruster with shower head type injector having one orifice was used to evaluate the HAN/Methanol propellant. The thermal stability of distributor was increased by using ceramic material to endure the high temperature of product gas. The preheating temperature of catalyst should be $400^{\circ}C$ at least for the complete decomposition. The feeding pressure should be increased to increase the $C^*$ efficiency, thereby the decomposition performance was decreased upstream catalyst, and the performance of thruster was decreased. The fine metal mesh was inserted after the injector to improve the atomization of propellant, thereby it can settle the performance decrease problem. The phenomenon of performance decrease was remarkably improved owing to the insertion of fine metal mesh.

• Korean Security Journal
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• no.10
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• pp.293-322
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• 2005

The culpability of a person, as determined by due process of law, for any of his actions that are defined as criminal. Determination of such responsibility is a legal function, not a psychiatric one, although a psychiatrist may be called upon to present evidence to the court in order to aid the judge or jury in reaching a decision as to responsibility. Determination of responsibility varies with the laws of the state in which the accused is being tried, but in general all states base their laws on three famous judicial decisions concerning criminal responsibility. 1. the M'Naghten(McNaughton) rule(a. to establish such a defense the accused, at the time the act was committed, must be shown to have been laboring under such defect of reason as not to know the nature and quality of the act he was doing, b. if he did know it, he did or know that what he was doing was wrong). 2. the irresistible impulse test. 3. the Durham decision. Under the Durham test, however, the psychiatrist may give any relevant testmony concerning the mental illness at issue. The psychological and behavioral appearance of a person, in clinical psychiatry this term is commonly used to refer to the results of the mental examination of a patient. The written report of the mental status usually contains specific references to the following areas: I. Attitude and General Behavior (1)General health and appearance. (2)General habits of dress. (3)Personal habits. (4)General mood. (5)Use of leisure time. (6)Degree of sociability. (7)Speech. II. Attitude and Behavior during interview (1)Co-operativeness. (2)Poise. (3)Facial expression. (4)Motor activity. (5)Mental activity. (6)Emotional reactions. (7)Trend of thought. III. Sensorium, mental grasp, and capacity (1)Orientation. (2)Memory and retention. (3)Estimate of intelligence. (4)Abstraction ability. (5)Tests of absurdity, interpretation of proverbs. (6)Judgment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.120-125
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• 2002

In the preceding tests using the KSR-III Sub.(I) engines, it was observed that the heat resistant capability of the engines was not enough for the mission. So Sub.(I) Mod. engines were designed and tested. The Sub.(I) Mod. engines have three major design parameters - the arrangement of main injectors, the impinging angle of main injectors and thermal barrier coating. More than twenty experiments were carried on to evaluate engine performance and heat resistance capability with respect to design parameters. In this study, the test results are introduced. Analysing the result of Sub.(I) engine tests, it is found that decreasing the impinging angle, adopting the H-type arrangement(rather than radial type arrangement) and adopting the thermal barrier coating can increase heat resistance capacity substantially. Also, engine performance evaluation is conducted using specific impulse and characteristic velocity parameter. The results show that the performance variation is small(about 5%) and the performance is better in the case of radial arrangement. It is suspected that these phenomena are caused by the change of flame structure atomization mixing characteristic of sprays and the distortion of recirculation zone. Also from the low frequency instability point of view, it is observed that reducing the impinging angle and adopting the H type arrangement can increase the instability characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.52-60
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• 2015

Operation area of corps was expanded under military reformation, and extending range of 155 mm howitzer became important issue. New approach is needed to extend range to 80 kim. Ramjet engine is air breathing engine, and it can provide specific impulse several times more than solid rocket motor so that range is extended using same weight of propellant. If the ramjet engine is gun-launched system, it does not require any other booster because muzzle velocity is near Mach 3. Especially solid fuel ramjet (SFRJ) does not have any moving part so that it is favorable for gun-launching system which is under high stress during launching. In this paper, we design air intake, combustion chamber, and nozzle of 155 mm gun launched ramjet propelled artillery shell with inviscid flow assumption. We conduct parameter study to have range more than 80 km, and maximum high explosive volume.