• Journal of the Korean Institute of Navigation
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• v.6 no.2
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• pp.57-63
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• 1982

This paper deals with a mathematical model which explains process of aquisition or skillfulness of human. Especially, in the case of determinating a ship's position, a degree of aquisitiion or skillfulness has a significant meaning in the view point of reliability of a data because it is closely connected with the position error. In this paper, the authors have obtained the following mathematical model, who analyzed quantitavely the data obtained by a process of measuring the horizontal sextant angles and extracted the factors or parameters affecting the process of aquisition or skillfulness of human. Namely, $H=Me^{-iN}$ M : the coefficiency which represent the degree of difficulty in measuring the object i : personal parameter N : the number of measurements

• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.307-316
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• 2006

Incomplete LU factorization preconditioning techniques often have difficulty on indefinite sparse matrices. We present hybrid reordering strategies to deal with such matrices, which include new diagonal reorderings that are in conjunction with a symmetric nondecreasing degree algorithm. We first use the diagonal reorderings to efficiently search for entries of single element rows and columns and/or the maximum absolute value to be placed on the diagonal for computing a nonsymmetric permutation. To augment the effectiveness of the diagonal reorderings, a nondecreasing degree algorithm is applied to reduce the amount of fill-in during the ILU factorization. With the reordered matrices, we achieve a noticeable improvement in enhancing the stability of incomplete LU factorizations. Consequently, we reduce the convergence cost of the preconditioned Krylov subspace methods on solving the reordered indefinite matrices.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.4
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• pp.320-328
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• 1994

In 1980 s to 1990 s the marine propulsion diesel engines have been developed into lower speed and longer stroke for the enegy saving (small S.F.O.C). As these new trends the conventional mechanical-hydraulic governors were not adapted to the new requirements and the digital governors have been adopted in the marine use. The digital governors usually use the control algorithms such as the PID control, optimal control, adaptive control and etc. While the engine has delay time and parameter variations these control algorithms have difficulty in considering the stability and the robustness for the model uncertainty. In this study, the $H_{\infty}$ controller design method are applied in order to design the feedback controller K(s) to the speed control of the low speed marine diesel engine, and the two-degree-of-freedom control system is constituted with $H_{\infty}$controller. By comparison of responses of the two-degree-of-freedom control system under the delay time and parameter variations is confirmed.

• Communications for Statistical Applications and Methods
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• v.19 no.4
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• pp.619-628
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• 2012

Noise reduction is an important issue in the field of image processing because image noise lowers the quality of the original pure image. The basic difficulty is that the noise and the signal are not easily distinguished. Simple smoothing is the most basic and important procedure to effectively remove the noise; however, the weakness is that the feature area is simultaneously blurred. In this research, we use ways to measure the degree of noise with respect to the degree of image features and propose a Bayesian noise reduction method based on MAP (maximum a posteriori). Simulation results show that the proposed adaptive noise reduction algorithm using Bayesian MAP provides good performance regardless of the level of noise variance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.395-398
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• 2001

In this paper, we consider to apply of 2-DOF (Degree of Freedom) PID controller at D.C servo motor system. Many control system use I-PD, PID control system but the position control system have difficulty in controling variable load and changing parameter. We propose neural network 2-DOF PID control system haying feature for removal disturbances and tracking function in the target value point. Experiment result for 2-DOF PID controller with neural network are illustrated.

• Journal of the Korean Dietetic Association
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• v.26 no.4
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• pp.254-268
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• 2020

This study examined the awareness, satisfaction, and usage patterns of 257 elementary school teachers for food labeling in Busan. The survey was conducted from April 15 to June 20, 2020, by questionnaires. The perception degree of food labeling was higher in female teachers than in male teachers and did not differ significantly among age groups. The score of the understanding degree was highest in their 20s and lowest in their 30s. The degree demand in their 50s was higher than in their 30s and 40s. The reliability degree in their 20s was higher than that of those in their 40s and 50s. The verification degree and satisfaction degree did not differ significantly with age or gender. The primary reason to check food labeling was 'to confirm harmful additives (31.9%)'. Among those in their 20s and 30s, the major reason for reviewing nutrition labeling was 'nutrient', while it was 'health improvement' was most important in those in their 40s and 50s. Of the subjects, 31.1% reported that the reason for the difficulty in understanding the label was 'various forms and the small letters'. The demand for the content was highest in trans fats. Apporximately 32.3% of the teachers were educated for food labeling; 42.4% of them taught food labeling, and 62.7% of them recognized the necessity of food labeling teaching. A correlation was observed between the demand for food labeling and understanding (r=0.586). Therefore, preparing education programs for teachers according to gender and age group and developing food additives-related programs will be necessary for strengthening the teachers' ability to manage their dietary life and educate students.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.89-94
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• 2020

This study attempted to investigate cognitive load, vividness, and cybersickness in nursing students, in the last year of nursing college, who used a 360-degree video content for studying intravenous fluid infusion, one of the core fundamental nursing skills. The aim was to determine the correlation between the variables, and to decide whether the 360-degree video content can be used as an effective supplementary educational material in the regular curricula. This study, a descriptive research, was conducted from October 31, 2019 to November 14, 2019. The participants in this study were 64 students in the 4th year of nursing college at a university located in B City, South Korea. They were instructed to watch a 360-degree video content for intravenous infusion using a Samsung Head Mounted Display (HMD) while ensuring the safety of the students. The results showed that the scores, out of 7 points, for material design, self-evaluation, and physical effort for cognitive load in nursing students were 5.93±0.71, 5.92±0.71, and 5.64±0.74 points, respectively. In addition, the scores, out of 7 points, for mental effort and task difficulty were 2.55±1.08 and 1.94±0.75 points, respectively, and the scores for vividness and cybersickness in the participants were 5.82±0.84, and 2.57±0.98 points, respectively. Physical effort, self-evaluation, and material design for cognitive load in the participants were positively correlated with vividness (r=.379, r=.458, r=.507). In addition, mental effort for cognitive load was positively correlated with cybersickness (r=.684), whereas self-evaluation and material design were negatively correlated with cybersickness (r=-.388, r=-.343). Based on the results of this study, we believe that the 360-degree video content for intravenous fluid infusion can be used as an educational medium in regular and non-regular curricula. In addition, future studies are needed to specifically develop and verify teaching and learning methods on how to apply 360-degree video contents..

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.600-610
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• 2022

While Korean piano pedagogy has seen a remarkable growth, the relatively weak attention to intermediate level has emerged as a pending problem. The limited literature review, specifically the lack of playing Korean original works, has been considered as a serious issue. To emphasize the usefulness of Kim Kukjin's "Pieces of Korean Melody for Piano" as an intermediate work, this study presents practical teaching guidelines by classifying of difficulty in his 25 pieces and providing step by step learning goals and teaching plan. The difficulty stage was based on Jane Magret's 10-step classification table for comparison with other intermediate piano literature, and this study more specifically classified Kim's pieces according to Korean melody, rhythm, and texture. As a result of the difficulty classification, it was found that the pieces from stages 4 to 10 was organized to systematically and comprehensively learn step by step from the most basic progression to Korean 'Jangdan' rhythm patterns, various articulations and decorations that express 'Sigimsae' of Korean Traditional Music, and heterophony texture. In addition, this study proposed the order of pieces for the effective teaching according to the characteristics and difficulty of the pieces. This study suggests that the findings lead to the expansion of Korean intermediate literature study and the revitalization of Korean original works teaching method.

• Journal of The Korean Association For Science Education
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• v.14 no.1
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• pp.85-102
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• 1994

The purpose of this study was to analyze students' physics problem solving processes and to find the patterns of their problem spaces when high school and university students solved the physics problems. A total of 51 students in a high school and in two universities participated in this study. Their thinking processes in solving 5 physics problems on electric circuit were recorded by using 'thinking aloud' method and were transferal into protocols. 'The protocols were analyzed by the coding system of problem solving process. One of the major theoretical contributions of the computer simulation approach to problem solving is the idea of problem space. Such a concept of problem space was applied to physics problems on electric circuit in this study, and students' protocols were analyzed by the basic problem spaces which were made up from the item analysis by the researcher. The results are as follows: 1) On the average 4.0 test items among 5 ones were solved successfully by all subjects, and all of the items were solved correctly by only 19 persons among all of them. 2) In regard to the general steps of problem solving process, there was little difference for each item between the good solvers and the poor ones. But according to the degree of difficulty of task there was a good deal of difference. For a complex problem all of 4 steps were used by most of students, but for a simple one only 3 steps except evaluating step were used by most of them. 3) It was found in this study that most of students used mainly the microscopic approach, that is, a method of applying Ohm's law on electric circuit simply and immediately, not using the properties of electric circuits. And also it was observed that most of students used the soloing tom below, that is, a solving path in which they were the first to calculate physical Quantities of circuit elements, before they caught hold of the meaning of the given problem regardless of the degree of difficulty.

• Physical Therapy Korea
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• v.10 no.2
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• pp.71-84
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• 2003

The purpose of this study was to provide information on driving characteristics in persons with spinal cord injury through basic statistic analysis of the survey results. The survey was administered to 44 drivers with spinal cord injury. The subjects' general, neurologic and driving characteristics were analyzed, as well as the degree of difficulty in using their vehicles between tetraplegia and paraplegia. The results were as follows: thirty-five (79.6%) of forty-four respondents was men. The average age was 35.0 years old and the age at the time of injury was 29.0 years old. Their neurologic characteristics were tetraplegics 12 (27.3%) and paraplegics 32 (72.2%). Among complete lesions, the highest level those who could drive independently was C7. All the vehicles were equipped with special devices, including "power steering", "automatic transmission" and "hand controls". The vehicles for cervical cord injury were equipped with "grip bars" as well as for the degree of difficulty in using their vehicles, all the subjects felt that "moving the wheelchair in and out of their vehicles" was too difficult for them to do. We suggest that the driver training should be an essential part of the rehabilitation program for patients with spinal cord injuries to maximize their mobility in the community. This training seems to be essential in order to modify the standards of the Handicapped Drivers Ability Test and to aid the driver rehabilitation program in the health insurance payment system. Also, the driver rehabilitation training program should include instruction in that moving wheelchairs in and out of vehicles.