• Korean Journal of Cognitive Science
• /
• v.18 no.2
• /
• pp.113-138
• /
• 2007

The effects of schema on accurate and false memories of items in a scene were investigated in two experiments: Recognition of items in a scene was tested immediately in Experiment 1 and three days later in Experiment 2. In both experiments, the following three variables were manipulated: Exposure time (250ms or 10000ms), picture mode (completed pictures or scrambled pictures), and manipulation mode (missing item or substituted item). Experiment 1 had yielded three important results: First, although accurate memory for presented items got increased when the exposure time was longer, false memory of the critical lures was not changed. Second, false memory of critical lures in the missing condition, where there was not any conflict between verbatim information and gist information, was higher than that of the substituted condition, where verbatim information of the item that replaced the lure was in conflict with the gist information. Third, accurate memory for atypical items in the substituted rendition, which had replaced the critical lures and in conflict with the schema, was higher than that in the missing condition. In Experiment 2, recognition test were administered 72 hours after the participants saw the picture. The three effects mentioned in Experiment 1 had disappeared in Experiment 2. The results of Experiment 2 might be due to the selective weakening of verbatim information compared to the persistence of the gist (or schematic) information. The results of Experiments 1 and 2 showed that false memory of critical lures is more persistent than the accurate memory of non-critical information. Theoretical implications of the results were considered in terms of the function of the verbatim and gist information.

• 유체기계공업학회:학술대회논문집
• /
• 2003.12a
• /
• pp.167-173
• /
• 2003

For the measurement of mass flow rate at a wide range of operation conditions, it is required that the critical nozzle gas different diameters, since the mass flow rate through the critical nozzle depends on the nozzle supply conditions and the nozzle throat diameter. In the present study, both computational and experimental investigations are performed to explore the variable critical nozzle. Computational work using the 2-dimensional, axisymmetric, compressible Navier-Stokes equations are carried out to simulate the gas flow through variable critical nozzle. In experimnet, a cylinder with several different diameters is inserted into the critical nozzle to vary the nozzle throat diameter. Computational results are compared with the experimented ones. The computed results are in close agreement with experiment. It is found that the displacement and momentum thickness of variable critical nozzle are given as a function of Reynolds numbers. The discharge coefficient of the variable critical nozzle is predicted using an empirical equation.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.10
• /
• pp.1419-1426
• /
• 2002

An experimental study was made to elucidate critical heat flux(CHF) characteristics in a two-phase concentric-tube thermosyphon. The experiment was performed by using saturated water, over the experimental range of configuration: inner diameter of heated outer tube D=12mm, outer diameter of unheated inner tube do=3 to 10mm and heated tube length L=100 to 1000mm. The experiment shows that the CHF is enhanced with increase in the inner tube diameter, and that the CHF decreases beyond a certain diameter of the inner tube. There is an optimum diameter for inner tube that maximizes the CHF, for each tube length and test liquid. The CHF maximum is about two to eight times as large as that without an inner tube. For a large inner tube, the CHF characteristics is similar to that for natural convective boiling in a vertical annular tube.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.613-616
• /
• 2006

The purpose of the this study of to define the critical corrosion amount of the steel cause the cracking of concrete cover. The major variables of the critical corrosion amount are concrete strength and thick of the concrete cover. In this experiment, the constant of stress concentration is added by a new variable. As a result of the experiment, it is confirmed to less decrease in the critical corrosion amount following the constants of stress concentration increased. Besides, electric currents were measured through a generator of constant voltage. When connecting constant voltage with corrosion circuit, it was discovered that magnitude of the change come out similarly between displacement on the concrete cover and electric current according to time.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.11
• /
• pp.1970-1975
• /
• 2008

Critical current of the superconducting machines is limited by the magnetic field. When the magnetic field is not uniform, it is difficult to estimate the magnetic field and the critical current. This paper proposed a method for the estimation of the magnetic field and the critical current of the HTS pancake windings which can be used to generate the high field magnet. A parameter which was needed to calculate the critical current of a BSCCO magnet with 10 pancake windings was obtained by the experiment. Test which was carried out by using single pancake winding and magnet consisting of 10 pancake windings shows the proposed method can be an effective method for the estimation of the critical current of pancake windings.

• Journal of Welding and Joining
• /
• v.1 no.2
• /
• pp.53-60
• /
• 1983

COD test based on fracture mechanics concept was used in this study to evaluate the fracture toughness quantitatively. Effects of specimen sizes on critical COD value for ABS EH 36 steel and its submerged arc weldments, and the variation of critical COD value depending on metallurgical/mechanical heterogeneities caused by weld thermal cycles were investigated. Experiment was performed by using specimens made from base metal and submerged arc weldments according to BS 5762. Obtained results are summarized as follows; 1) Critical COD value for base metal decreases with increasing thickness of specimen. On hand, as the reduction ratio of critical COD decreases with increasing specimen thickness, critical COD value becomes constant above a thickness of specimen. 2) Critical COD value for weldment decreases with increasing thickness of specimen and was also affected by metallurgical states of base metal. 3) Size effects for weldment was greater at the hardened region. 4) Critical COD value was affected by microstructural change due to weld thermal cycles in weldments; that is, accicular ferrite formation is favorable for increasing of COD value.

• The Mathematical Education
• /
• v.50 no.1
• /
• pp.69-87
• /
• 2011

The aim of this research is to develop a 'program which improves critical thinking' to improve elementary school students' mathematical thinking, and investigate the effect of program by applying and verifying the program. In order to achieve the objective, the author determined the factors of critical thinking capabilities matched to the discipline of mathematics, and accordingly designed relevant programs and test questions for critical thinking skills which contributes to improving the critical thinking of elementary school students, and thus applied the program the developed program of improving the critical thinking to both preliminary and main experiments, which verified the effects of the test method. The following results have been acquired through this research : In the preliminary inspection that this researcher has developed, it was able to predict that 'the program which improves critical thinking' would have a positive influence on the students' critical thinking. In the main experiment which was performed after modifying and supplementing it, the result showed that the program had a positive influence on the students' critical thinking.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.484-489
• /
• 2003

The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle.

• Journal of Korean Elementary Science Education
• /
• v.28 no.2
• /
• pp.105-120
• /
• 2009

Critical Experiments (CE) in science classrooms mean, tentatively, critical situations as comparable to anomalous cases in scientific revolutions where the results of science experiments in schools are unclear, differ from the theory, or students misunderstand the purpose of the experiments. The purpose of this research is to identify what CE occurred during science classes and to investigate how elementary teachers handled them. To analyze how teachers recognized and handled CE, we selected nine typical CE from the $7^{th}$ Korean science curriculum. 125 teachers were selected from 8 districts' elementary schools in a local city. A questionnaire with photos of the nine CE above-mentioned was distributed to these teachers. The focus in this research was the way that each teacher handled the CE. We discovered that there were three basic ways in which teachers handled CE. When CE occurred, 51% of elementary teachers explained the correct result of the experiment (what should have happened) to the students while 40.7% of the teachers repeated to get the correct results. The focuses of handling CE varied. 57 % of the teachers focused on the 'materials' while 30% of the teachers focused on the 'theory'. The other focus was 'thinking'. Only 7.6% of the teachers answered that they gave students a chance to think about the reasons why the CE happened. By analyzing our survey results, we could determine what each teacher did as a follow up to the CE and their focus and reasoning for handling the CE this way. When the CE happened in the science class, few handled the CE with the point of view about purpose of doing experiment. As a result, students could not gain educational experience from the CE. If we use CE as a new method to teach science, it will be a good subject incorporating the nature of science in science education.

• Journal of Korea Water Resources Association
• /
• v.53 no.3
• /
• pp.167-179
• /
• 2020

Recently, new levee material has been developed to enhance natural soil strength and vegetation growth using biopolymer. In the study, critical tractive force of vegetated mats mixed with biopolymer mixed soil has been evaluated to apply the mixed soil to levee construction material. The mixed soil has been produced by mixing beta-glucan, clay, and sand. Full scale test bodies have been constructed with 3 cm thick of the mixed soil. Total 4 test bodies have been constructed and experimented. Critical tractive forces have been evaluated by observation and measurement of failure conditions and soil loss. Although performance of the vegetated revetments are affected by vegetation coverage conditions, the critical tractive forces are shown about 40 N/㎡ and the critical velocities are shown about 4 m/sec by full scale experiment. Erosion resistance is also enhanced by combination of root and net with mat materials.