• Research in Mathematical Education
• /
• v.17 no.1
• /
• pp.15-27
• /
• 2013

Division of fractions is always a difficult topic for primary school students. Most of the presentations in teaching the topic in textbooks are procedural, asking students to invert the second fraction and multiply it with the first one, that is, $$\frac{a}{b}{\div}\frac{c}{d}=\frac{a}{b}{\times}\frac{d}{c}$$. Such procedural approach in teaching diminishes both the understanding of structure in mathematics and the interest in learning the subject. This paper discussed the formulation of teaching the division of fractions, which based on research lessons in some primary five classrooms. The formulated lessons started with an analogy to division of integers and working with division of fractions with equal denominators and then extended to division of fractions in general. It is found that the using of analogy helps students to invent their procedure in working the division problem. Some procedures found by students are discussed, with the focus on the development of their invention and mathematical thinking.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.1
• /
• pp.157-163
• /
• 2012

Objective: This study is to understand medical management method in shipbuilding industry. Background: In shipbuilding industry, medical management for prevention of work-related musculoskeletal diseases due to limitations of engineering measures may be important measure. Results: Medical management of musculoskeletal diseases can be divided into primary, secondary, tertiary preventions. Primary preventions consist of symptom survey, appropriate work placement with work capacity evaluation, health promotion. Second preventions are early detection of symptomatic patient and appropriate treatment. Tertiary preventions are rehabilitation treatment and early return-to-work by return-to-work evaluation. In addition, patients with psychological counseling for emotional problems are needed. Conclusion: Medical management measures such as improving the work environment to be made are expected to exert greater effects.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.4
• /
• pp.645-653
• /
• 2003

Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to tie brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas tile second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.

• Journal of Chest Surgery
• /
• v.23 no.2
• /
• pp.396-401
• /
• 1990

This report is an review of 5 cases of congenital esophageal atresia associated with tracheoesophageal fistula which were treated in the Department of Thoracic and Cardiovascular Surgery, Chonnam University Hospital from January, 1987 to February, 1989. First patient that was associated with VATER’s syndrome and moderate pneumonia, i.e., Waterston Category C was treated by gastrostomy, colostomy and primary anastomosis, but expired. Second patient that was weighed 2.2 Kg, suffered from moderate pneumonia was treated by gastrostomy, but died from asphyxia. The other patients were treated by primary repair. Any anastomotic leakage or gastroesophageal reflux was not found in these cases, but mild anastomotic strictures were found in these patients by postoperative esophagography. However, esophageal dilatation of anastomotic strictures was successful using the Griintzig balloon catheter.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1994.10a
• /
• pp.200-204
• /
• 1994

Low temperature associated damage mechanism is not well known for asphalt concrete. Many studies have related the thermal cracking of pavement in the roadway in cold region with overall shrinkage of the pavement surface under assumption of homogeneous material. This study, however, was intiated based on the assumption that thermal incompatibility of materials (heterogeneous) in asphalt concrete mixture would be the primary cause of the damages. Acoustic emission technique and microscopic obsevation were employed to evaluate damage mechanism of asphalt concrete due to low temperature. The first method showed the sufficient evidence that asphalt concrete could be damaged by lowered temperature only. The second method showed that the damage by temperature resulted in micro-cracks at the interface between asphalt matrix and aggregate particle. It was concluded that these damage mechanisms were the primary cause of major thermal cracking of asphalt pavement in cold region.

• Journal of the Korean Society of School Health
• /
• v.1 no.1
• /
• pp.148-159
• /
• 1988

For the evaluation of physical assessment by school nurses, this study was designed in two steps physical assessment. The first step is the primary health screening by school health nurses. The second step is the Physicians' physical examination of ill health students selected by school nurses. This study was conducted on a total of 3,525 students of three primary schools located in urban, township, and rural area during the period from May to June, 1987, all data were collected through direct observation & survey method. The main findings are as follows 1. The number of ill health students selected by two step method was more than that of one step method by the physician. 2. The types of ill health students selected by two step method had more diversity than that of one step method by the physician. 3. Budgets and time consumption for two step method were more reductive than that of one step method by the physician.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.16 no.4
• /
• pp.12-19
• /
• 2008

GIOVE-B is the second experimental Galileo satellite for the Galileo In-Orbit Validation, which was launched by a Soyuz/Fregat rocket departing from the Baikonur cosmodrome in Kazakhstan on 27 April and now operated successfully. This paper presents the results obtained from processing of the E5a signal transmitted from the GIOVE-B. The acquisition and tracking of the data and pilot channels are performed by the E5a software receiver implemented by ETRI. Moreover, the paper suggests the GIOVE-B E5a-I/E5a-Q secondary code, which is determined by analyzing the correlation output of the primary correlator using the primary code.

• Journal of the Korean Society of Combustion
• /
• v.18 no.4
• /
• pp.21-28
• /
• 2013

HCCI engines have mainly focused on achieving low temperature combustion in order to obtain higher efficiency and lower emission. One of practical difficulties in HCCI combustion is to control the start of combustion and subsequent combustion phasing. The choice of primary reference fuels in HCCI strategy is one of various promising solutions to make HCCI combustion ignition-controlled. The behavior of ignition delay to the frequency variation of sinusoidal velocity oscillation is computationally investigated under HCCI conditions of PRF75 using a reduced chemistry in a counterflow configuration. The second-stage ignition is more delayed as the higher frequency is imposed on nozzle velocity fluctuation whereas the first-stage ignition is not much influenced.

• KIEAE Journal
• /
• v.14 no.4
• /
• pp.47-52
• /
• 2014

The problem of energy consumption is more serious in university buildings than primary, middle and high school buildings. Because university buildings have generally heating and cooling systems, and various incidental facilities. In university, the library is one of the building that many people use and the most energy is spent. So, investigation on energy saving is very important and urgent. This study aims finally to present the guideline for low-energy design of University library by aiding a designer to select best solution in the side of energy-saving. In this paper, composition of space, utilization schedule and performance of construction materials are grasped, some primary factors that effect to energy saving are analyzed by energy simulation. The result of this study is as follows; First, the subject library has more cooling load than heating load because of cooling load generated during middle season. Second, green roofs is the most effective to heating load saving, but not to cooling energy. Third, outdoor air cooling is the most effective to cooling energy saving among the investigated strategies included in this study.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2001.10a
• /
• pp.123-130
• /
• 2001

At present, the virtual prototyping technology for complex product is one of the research and application hotspots in current simulation technology. In authors viewpoint, the virtual prototype development for complex product has become a systematic engineering, which can be called the complex product virtual prototyping engineering (CPVPE). In this paper, the architecture, key technologies and its supporting environment of CPVPE are primary discussed firstly. Combined with the research project and primary practice undertaken by the authors, a typical application demonstration of the aerospace complex product virtual prototyping engineering (including mechanism, dynamics, software and control system) is also introduced based on the virtual prototype supporting environment developed by the authors. Finally, some further research works on CPVPE are also presented in this paper.