• Communications of Mathematical Education
• /
• v.32 no.3
• /
• pp.297-314
• /
• 2018

This article aims at providing implication for teacher preparation program through interpreting pre-service teachers' knowledge by using Shulman-Fischbein framework. Shulman-Fischbein framework combines two dimensions (SMK and PCK) from Shulman with three components of mathematical knowledge (algorithmic, formal, and intuitive) from Fischbein, which results in six cells about teachers' knowledge (mathematical algorithmic-, formal-, intuitive- SMK and mathematical algorithmic-, formal-, intuitive- PCK). To accomplish the purpose, five pre-service teachers participated in this research and they performed a series of tasks that were designed to investigate their SMK and PCK with regard to students' misconception in the area of geometry. The analysis revealed that pre-service teachers had fairly strong SMK in that they could solve the problems of tasks and suggest prerequisite knowledge to solve the problems. They tended to emphasize formal aspect of mathematics, especially logic, mathematical rigor, rather than algorithmic and intuitive knowledge. When they analyzed students' misconception, pre-service teachers did not deeply consider the levels of students' thinking in that they asked 4-6 grade students to show abstract and formal thinking. When they suggested instructional strategies to correct students' misconception, pre-service teachers provided superficial answers. In order to enhance their knowledge of students, these findings imply that pre-service teachers need to be provided with opportunity to investigate students' conception and misconception.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.2
• /
• pp.85-91
• /
• 2016

The Positive Temperature Coefficient (PTC) is used for cabin air heating of a battery electric vehicle, which is different from conventional vehicles. Since the PTC heater consumes a large quantity of power in a parasitic manner, many valuable studies have been reported in the field of alternative heat pumps. In this study, a model for an R134a heat pump taking into account the thermal environment of the cabin was developed for a MATLAB/SIMULINK(R) platform. Component and cabin models are validated with reference values. Results show that the heat pump is more competitive for parasitic power consumption over all ambient temperature conditions. Additionally, the method of waste heat recovery to overcome disadvantages when temperatures are below zero is applied to efficiently operate the heat pump.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.5
• /
• pp.289-296
• /
• 2016

The availability of NMP, a solvent used in the manufacturing process of cathode material for lithium ion battery, depends on importation, and the price remains high because of the monopoly of BASF and ISP. For these reasons, most Lithium ion battery manufacturers reuse NMP after recovering it from the exhaust air in the drying process. In Korea, absorption method is mainly used for recovering NMP from the absorption tower using the hydrophilicity of NMP. However, this system has a few disadvantages, such as low purity (80％) of the recovered NMP and 100％ emission due to high water content of the treated gas. In this study, we develop a hybrid NMP recovery system by combining cooling condensation method with concentration method, by which it is possible to obtain an NMP recovery rate of 99.6％, and a high purity (96.1％) of the recovered NMP.

• The Journal of the Korea Contents Association
• /
• v.15 no.10
• /
• pp.425-435
• /
• 2015

While managerial coaching has increased popularly as an effective leadership initiative in organization, the relationship between managerial coaching and its effects on performance has not been scholarly well defined. This study examined the role of managerial coaching as a moderator between job characteristics and job performance. Based on the sample of 453 employees in a financial firm, HLM was conducted to test the research model at multiple levels of organizational hierarchies. First, we found that managerial coaching has a direct impact on employee performance. Second, the strength of the relationship between job meaningfulness and job performance is positively related to the level of managerial coaching. Third, managerial coaching positively moderates the association between autonomy and job performance. However, any cross-level moderating effects of managerial coaching on the relationship between feedback and job performance is not observed. These results show that managerial coaching by managers could promote employees' performance through maximizing the impact of job characteristics on employees' motivation.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.269-281
• /
• 2012

The purpose of this study is to analyze effects of medical service quality on the customer satisfaction and intention of revisit in cancer patients. To achieve purpose of the research, the data was collected from 420 patients in university hospitals using a standardized questionnaires. Using the structural equation modeling(SEM), this study examines the relationship among medical service quality, customer satisfaction and intention of revisit. The results show that the medical service quality factors such as medical expertise, administrative service have positive effects on the customer satisfaction which positively relates to intention of revisit. Medical expertise, convenience, administrative service of the medical service quality factors have positive influence upon intention of revisit. Therefore, the results of this study show that the medical service quality factors which are medical expertise, administrative service leading to customer satisfaction are important factors to revisit hospitals.

• Journal of the Korean Society of Radiology
• /
• v.14 no.3
• /
• pp.253-259
• /
• 2020

Mammography has the advantage of being economical, simple and effective in detecting microcalcification, but breast is a highly sensitive organ and is accompanied by the risk of an over-exposure. While accurate dose assessments are important to prevent this, current breast dose assessments are limited to breast implant patients. This purpose of this study was to identify dose variations due to tube voltages by forming a mock-up with breast implants for an accurate dosimetric assessment on breast implant patients. As a result, doses from the presence of breast implants were smaller than those from the absence of the mammal. As the result of the change of the voltage to 26, 28, 30, and 32 kV, the imcreased tube voltage included larger dose regardless of the presence of Breast implant. Therefore, it is believed that diagnosis recommendations for breast implants will be possible if further studies on internal and external bioretical imaging and quality assessment are carried out as the basis for this study.

• Journal of Preventive Medicine and Public Health
• /
• v.29 no.2 s.53
• /
• pp.255-264
• /
• 1996

To study reliability and validity of PWI, this newly developed self-administered questionnaire which measures stress, was given to medical students. All respondent(133) were followed 4 weeks later and 92 were retested. Cronbach's $\alpha$ coefficient of data was 0.93. Test-retest reliability measured by Pearson's correlation coefficient was 0.72(P<0.01). Exploratory factor analysis(EFA) performed by principal axis factor method without iteration and by varimax rotation explored 13 principal components(eigenvalues > 1). After exploring 4 factor structure according to previous study results, factor 1 showed good agreement but other factors did not. Confirmatory factor analysis(CFA) showed poor fit of 4 factor model to data. In the further study, it may be considered to model that has unidimensional factor structure.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.2
• /
• pp.179-185
• /
• 2015

Although an accelerometer is a sensor that measures acceleration, it cannot be used by itself to measure the acceleration when the orientation of the sensor changes. This paper introduces a Kalman filter for the estimation of a sensor acceleration based on a six-axis inertial sensor (i.e., a three-axis accelerometer and three-axis gyroscope). The novelty of the proposed Kalman filter lies in the fact that its state vector includes not only the tilt angle variable but also the sensor acceleration. Thus, the filter can explicitly estimate the latter with a high accuracy. The accuracy of acceleration estimates were validated experimentally under three different dynamic conditions, using an optical motion capture system. It could be concluded that the performance of the proposed Kalman filter was comparable to that of the state-of-the-art estimation algorithm employed by the Xsens MTw. The proposed algorithm may be more suitable than inertial/magnetic sensor-based algorithms for various applications adopting six-axis inertial sensors.

• The Korean Journal of Food And Nutrition
• /
• v.22 no.3
• /
• pp.352-356
• /
• 2009

In this study, we evaluated black pepper seed and white pepper seed for the following compounds: piperine content was determined by HPLC, and volatile oil content was determined via the Soxhlet method in before/after heat-treated samples, and total volatile material contents were determined via the SDE(Linkens-Nikens type simultaneous steam distillation and extraction apparatus) method. As a result, differences were noted in the black and white pepper seeds according to the constituent components, growing district, and whether the species was indigenous to Indonesia or India. We concluded that the differences in taste were attributable to the differences in the volatile material contents in black and white peppers. We also assessed these three determination results, and found that they were directly correlated. The volatile oil contents were determined by the Soxhlet method, which was a rapid, simple, and accurate method. We concluded that this method should prove to be an effective determination method in the quality control of black and white peppers.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.6
• /
• pp.665-674
• /
• 2015

A TSL (Thin Spray-on Liner) which consists of polymers has a higher initial strength, faster construction time and higher waterproofing performance than the conventional cementitious shotcrete. Main supporting mechanism of TSL is the adhesion and tensile strength which is distinct from the conventional shotcrete. Even though highly in demand due to its outstanding characteristics, TSL is not yet well-known support material. In this study, to evaluate contact behavior of TSL, numerical analysis was performed with comparing result from laboratory tests. From the analysis, cohesive behavior at the contact surface between TSL and rock can be evaluated by using combination of cohesive and the damage model. In addition, results show that the cohesive stiffness controled slope between force and displacement, the fracture energy controled level of force at the contact.