• Communications of Mathematical Education
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• v.34 no.3
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• pp.235-256
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• 2020

The purpose of this study was to investigate the experience of pre-service mathematics teachers who attended at a university course combined with teaching practicum based on design thinking process to identify the change of their awareness of its activities. For the research, 8 pre-service mathematics teachers participated in a mathematics major course, consisting of 5 phases of design thinking formed by Stanford d.school. In the end of the course, qualitative data were collected through individual and focus group interviews and the course activities. By data analysis, the results of this study were as follows. Firstly, the participants' perspectives of design thinking activities were changed from the difficulty and ambiguity of its activity in the beginning of the process to positiveness with competence of solving authentic problem in terms of teaching practicum over time. Secondly, the participating pre-service teachers emphasized that design thinking activities helped them prepare well teaching practicum and raise understanding of students they met in the school fields. Thirdly, some research participants went through the difficulty in utilizing their products drawn from 4th phase (prototyping) of design thinking process depending on the acceptance of their guidance teachers. Fourthly, the research participants also pointed out that the design thinking was a significant activity in that they learned how to understand and communicate with their students and how to collaborate with team members and it gave an insight about the preparation for a class. Through these results, this study identified the possibility of using the design thinking process for pre-service mathematics teachers' teaching practicum. In addition, the research put forward some implications for better use of design thinking in teacher education.

• Korean Journal of Digital Imaging in Medicine
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• v.5 no.1
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• pp.32-44
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• 2002

The role of radiology department has been greatly increased in the past few years as the technology in the medical imaging devices improved and the introduction of PACS (Picture Archiving and Communications System) to the conventional film-based diagnostic structure is a truly remarkable factor to the medical history. In addition, the value of using digital information in medical imaging is highly expected to grow as the technology over the computer and the network improves. However, the current medical practice, using PACS is somewhat limited compared to the film-based conventional one due to a poor image quality. The image quality is the most important and inevitable factor in the PACS environment and it is one of the most necessary steps to more wide practice of digital imaging. The existing image quality control tools are limited in controlling images produced from the medical modalities, because they cannot display the real image changing status. Thus, the image quality is distorted and the ability to diagnosis becomes hindered compared to the one of the film-based practice. In addition, the workflow of the radiologist greatly increases; as every doctor has to perform his or her own image quality control every time they view images produced from the medical modalities. To resolve these kinds of problems and enhance current medical practice under the PACS environment, we have developed a program to display a better image quality by using the ROI optical density of the existing gray level values. When the LUT is used properly, small detailed regions, which cannot be seen by using the existing image quality controls are easily displayed and thus, greatly improves digital medical practice. The purpose of this study is to provide an easier medical practice to physicians, by applying the technology of converting the H-D curves of the analog film screen to the digital imaging technology and to preset image quality control values to each exposed body part, modality and group of physicians for a better and easier medical practice. We have asked to 5 well known professional physicians to compare image quality of the same set of exam by using the two different methods: existing image quality control and the LUT technology. As the result, the LUT technology was enormously favored over the existing image quality control method. All the physicians have pointed out the far more superiority of the LUT over the existing image quality control method and highly praised its ability to display small detailed regions, which cannot be displayed by existing image quality control tools. Two physicians expressed the necessity of presetting the LUT values for each exposed body part. Overall, the LUT technology yielded a great interest among the physicians and highly praised for its ability to overcome currently embedded problems of PACS. We strongly believe that the LUT technology can enhance the current medical practice and open a new beginning in the future medical imaging.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.64-69
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• 2007

Motion control of the system is a position control of motor. Motion control of an uncertain robot system is considered as one of the most important and fundamental research directions in the robotics. Some distinguished works using linear control, adaptive control, robust control strategies based on computed torque methodology have been reported. However, it is generally recognized within the control community that these strategies suffer from the following problems : the exact robot dynamics are needed and hard to implement, the adaptive control cannot guarantee the performance during the transient period for adaptation under the variation, the robust control algorithms such as the sliding mode control need information on the bounds of the possible uncertainty and disturbance. And it produces a large control input as well. In this dissertation, a motion control for the unmanned intelligent robot system using disturbance observer is studied. This system is affected with an impact vibration disturbance. This paper describes a stable motion control of the system with the consideration of external disturbance. To obtain the stable motion independently against the external disturbance, the disturbance rejection is strongly required. To address the above issue, this paper presents a Disturbance OBserver(DOB) control algorithm. The validity of the suggested DOB robust control scheme is confirmed by several computer simulation results. And the experiments with a motor system is performed to give the validity of applicability in the industrial field. This results make the easier implementation of the controller possible in the field.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.484-494
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• 2002

This study was conducted to validate the semi-quantitative food frequency questionnaire that was developed to assess the intakes of fatty acids, as well as energy, carbohydrates, fat, protein, minerals and vitamins in Korean adults. The validity of the semi-quantitative food frequency questionnaire was tested on 78 subjects (31 men,47 women) aged 34 to 66 years. The semi-quantitative food frequency questionnaire included 93 food items and was validated on two 3-day dietary records. The mean intakes and the Spearman Correlation Coefficients between the semi-quantitative food frequency questionnaire and the two 3-day dietary records were analyzed for each nutrient and food group level. The mean nutrient intakes obtained from the semi-quantitative food frequency questionnaire were estimated to be greater than those of the two 3-day dietary records. The Spearman Correlation Coefficients between the energy-adjusted nutrient intakes from the semi-quantitative food frequency questionnaire and the two 3-day dietary records ranged from 0.24 for polyunsaturated fatty acids to 0.55 for fat in men and from 0.29 for polyunsaturated fatty acids to 0.55 for saturated fatty acids in women, respectively. The Spearman Correlation Coefficients for food intake ranged from 0.11 for teas and beverages to 0.58 for grains and their products in men,-0.04 for potatoes and starches to 0.73 for milk and dairy products in women. Foods consumed regularly had lower intra-person variation and tended to have higher observed correlation coefficients. These results indicate that the semi-quantitative food frequency questionnaire is a useful tool for estimating nutrient intakes, particularly of total fat and saturated fatty acid intakes.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.209-215
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• 2003

In this paper. We tested and fabricated the error amplifier for the 15 Watt linear power amplifier for the IMT-2000 baseband station. The error amplifier was comprised of subtractor for detecting intermodulation distortion, variable attenuator for control amplitude, variable phase shifter for control phase, low power amplifier and high power amplifier. This component was designed on the RO4350 substrate and integrated the aluminum case with active biasing circuit. For suppression of spurious, the through capacitance was used. The characteristics of error amplifier measured up to 45 dB gain, $\pm$0.66 dB gain flatness and -15 dB input return loss. Results of application to the 15 Watt feedforward Linear Power Amplifier, the error amplifier improved with 27 dB cancellation from 34 dBc to 61 dBc IM$_3$.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.131-136
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• 2008

Silica- or titania-filled poly (vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes were prepared by phase inversion technique using N-methyl-2-pyrrolidone and dimethyl acetamide as solvent and water as non-solvent. The polymer electrolytes were adopted to the lithium metal polymer battery using high-capacity cathode $Li[Ni_{0.15}Co_{0.10}Li_{0.20}Mn_{0.55}]O_2$ and lithium metal anode. After the repeated charge-discharge test for the cell, it was proved that the cell adopting the polymer electrolyte based on the phase-inversion membrane containing 40~50 wt% silica showed the highest discharge capacity (180 mAh/g) until 80th cycle and then abrupt capacity fade was just followed. The capacity fade might be due to the deposition of lithium dendrite on the polymer electrolyte, in which the capacity retention was no longer sustainable.

• Journal of the Korean Dietetic Association
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• v.15 no.4
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• pp.335-342
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• 2009

Forty-two percent of the patients with renal failure that requires continuous renal replacement therapy (CRRT) have been reported to have severe malnutrition, and preexisting malnutrition is a statistically significant and independent predictor of negative hospital outcomes. We performed this study to evaluate the appropriateness of the calorie and protein provided for the critically ill patients who require CRRT. One hundred forty-nine patients who received CRRT were enrolled. The demographic data, the length of the ICU stay and the mortality were recorded. The calorie/protein intake and the blood urea nitrogen (BUN), albumin and creatinine levels were used as nutritional parameters. The mean daily calorie intake during CRRT was 16.1${\pm}$7.4 kcal/kg, which was 64% of the recommended intake. Only 10% of the patients received the recommended caloric intake and the ratio of the enteral and parenteral calories was 26%/74%. The mean protein intake was 0.58${\pm}$0.34 g/kg, which was 38% of the recommended intake. The calorie and protein intakes at the termination of CRRT were significantly increased compared to the initial day of treatment, but they stayed under the recommended intake. The BUN, creatinine and albumin levels were significantly increased in the survival group (odds ratio for albumin: 2.73; creatinine: 2.43). A strategy to increase the nutrition provision is needed to improve the nutritional statuses and clinical outcomes of the critically ill patients who require CRRT.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.437-442
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• 2013

Objective: The objective of this study was to investigate the effects of drive-assisting system in a shower carrier on the upper body muscle activities of caregivers through drivability tests. Background: In care facilities, one of the major ADL (Activities of Daily Living) factors is bathing/showering. Recently, bath/shower-assisting equipment is actively being introduced in care facilities to reduce caregivers' muscle burden. In particular, it is desirable to utilize a shower carrier equipped with drive-assisting system to effectively care for the elderly. However, there were few systematic studies on the relationship between muscle activities and drive-assisting speeds. Method: For the drivability tests to study the effects on the muscle activities according to the drive-assisting speeds(corresponding drive-voltages: 0.0V, 2.0V, 2.1V, 2.3V), 6 females in their 40s($43{\pm}4yrs$, $157{\pm}5cm$, and $54.5{\pm}1.5kg$) were selected. To measure muscle activities of caregivers through drivability tests, 7 muscles in the upper body(TM/Trapezius Muscle, DM/Deltoid Muscle, BBM/Biceps Brachii Muscle, TBM/Triceps Brachii Muscle, ECRLM/Extensor Carpi Radialis Longus Muscle, FCUM/Flexor Carpi Ulnaris Muscle, and ESM/Erector Spinae Muscle) were selected. Results: In the TM, muscle activities were decreased as 21% compared to 0.0V, when drive-voltage 2.0V was applied, as 57% by 2.1V, and 62% by 2.3V(p<0.05), whereas 40%, 56%, and 69% of muscles activities were decreased respectively from the DM(p<0.05). Also, from the UL(BBM+TBM+ECRLM+FCUM), muscle activities were decreased by 17% with 2.0V as against 0.0V, by 47% with 2.1V, and 52% with 2.3V, whereas decreases in muscle activities from the ESM were found by 20%, 34%, and 42% respectively by 2.0V, 2.1V, and 2.3V(p<0.05). Conclusion: The muscle activities were decreased in the order of the DM, TM, ESM, and UL. As muscle activities were remarkably reduced as drive voltage were increased, it was expected to reduce the upper body muscle burden on the caregivers when using shower carriers equipped with driving-assist system. Applications: The results from this study can be applied for the development of a shower carrier including other equipment to possibly reduce the muscle burden of the caregivers.

• Journal of Korean Clinical Nursing Research
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• v.19 no.3
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• pp.432-442
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• 2013

Purpose: The purpose of this study was to describe restraint use in care of patients with psychiatric disorders in an attempt to avoid unnecessary restraint use and provide information for developing standards regarding restraint use as a therapeutic maneuver. Methods: For this descriptive study, discharge records from N National Mental Hospital in the year 2009 were reviewed by trained nurses during Dec. 24, 2010 and Mar. 31, 2011. There were 596 restrains applied on 232 of 1,322 discharges. Data collected include general characteristic of patients, the frequency of restraint use, time since admission when restraint was applied, time of the day when restraint was applied, duration of restraint application, place of occurrence, reasons for restraint use, and degree of damage to the patent. Work experience of nurses who applied restraints, number of workforce at the time of restraint, and season of the year was also identified. Descriptive statistics, Chi-square test, t-test, ANOVA, $Scheff{\grave{e}}$ and Jonckheere-Terpstra were applied using SPSS 14.0 to analyze the data. Results: There were 596 restraint uses among 232 patients. Restraints were applied most frequently on males in their 40s, patients diagnosed with schizophrenia, and patients repeating admissions more than 6 times. Restraints were frequently applied within first week following admission, between 16:00 and 20:00, and the average duration of restraint was 5 hours. There were significant differences according to diagnoses of patients in the season restraint occured, time, place of occurrence, reason for restraint, and duration of restraint. Patients with alcoholism received longer restraint application. Conclusion: In order to avoid unnecessary restraint use in patients with psychiatric disorders, nurses and other health care team members need to acknowledge a group of patients such as patients with schizophrenia and alcoholism who relatively frequently restrained or receiving longer restraint. Reasonable and careful decision need to be made when applying restraint in the care of patients with alcohol problem.

• Polymer(Korea)
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• v.33 no.4
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• pp.389-395
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• 2009

To develop the carrier of hydrophobic antifungal agents based on low molecular weight water-soluble chitosan (LMWSC), LMWSC was chemically modified with deoxycholic acid (DA) which is one of the bile acid as a hydrophobic group. The nanoparticles (WSCDA) using DA conjugated LMWSC were characterized using dynamic light scattering (DLS) and transmittance electron microscope (TEM). The particle size of WSCDA ranged from 250 to 350 nm and increased with the number of DA substitution. The loaded itraconazole as an antifungal agent WSCDA nanoparticles (WSCDA-ITCN) were prepared by solvent evaporation method. The drug content and the loading efficiency were investigated approximately $9{\sim}10%$ and $61{\sim}68%$ by UV spectrophotometer, respectively. The release of drug from nanoparticles was slow and showed sustained release characteristics. Based on the results of release study that the higher DA contents in WSCDA, the slower the releasing rate, the WSCDA-ITCN could be used as an excellent antifungal agent.