• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.2 no.2
• /
• pp.63-68
• /
• 2009

We study on the transient response in non-uniform microstrip lines with optically controlled microwave pulses. The transient response of the microwave pulses in plasma layer has been evaluated by reflection function of dielectric microstrip lines. The variation of characteristic response in plasma layer with localized pulses has been evaluated analytically. Reflection the change of the reflection amplitude has been observed.

• Journal of Magnetics
• /
• v.6 no.2
• /
• pp.43-46
• /
• 2001

The reflection-amplitude approximation is used to calculate the interlayer exchange coupling in (001) Co/Cu/Co multilayers. The dependence of the phase factor of the reflection amplitude on the energy and wave vector is included. The contribution of each period is calculated and the results are compared with those from asymptotic behavior. It is shown that the energy and wave-vector dependence of the phase factor may affect the interlayer exchange coupling significantly.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.16 no.4
• /
• pp.438-448
• /
• 2009

Purpose: To examine the results of PBL classes for sophomore nursing students during one semester. Method: Self-reflection journals and class evaluation questionnaires were collected from 121 nursing students and analyzed. Results of class evaluation questionnaires were analyzed using mean scores, SD, frequencies and percentages. Significant statements were derived by repeated review of the self-reflection journals by the researchers. Results: The statements, 'Understanding of PBL' 'Improvement of human relationships' 'Expansion of nursing knowledge' 'Excellency in nursing class and application of nursing skills in nursing practices' and 'Improvement of learning ability and attitude during classes' were derived from the self-reflection journals. Analysis of class evaluation questionnaires showed the following scores: prerequisite of PBL (3.0/4), role of facilitator (3.48/4) and satisfaction with PBL learning (3.31/4). Also some complaints such as lack of adequate references in the library, and confusion in at the beginning of PBL were noted. Conclusion: PBL was effective. Using the results of the study for planning a more effective PBL class syllabus is recommended.

• Journal of Engineering Education Research
• /
• v.11 no.1
• /
• pp.5-14
• /
• 2008

The purpose of this study is to analyze how a well-structured cognitive reflection journal can affect a learner's metacognition and learning achievement in the area of Engineering Education. The objects of this study were 143 students in total (experimental group: 52, control group: 91) who are taking the 'Fundamental Semiconductor Engineering' course in the Engineering Department at D college in the metropolitan area. For his particular study, we undertook three steps as follows. First, we verified that the two groups of students were equal in areas of metacognition and learning achievement. Second, the experimental group was asked to keep writing the well-structured reflection journal for four weeks and the control group was not. Third, we evaluated the metacognition and learning achievement. This study used a questionnaire to measure metacognition by Sperling(2002) in a Korean translation as well as a well-structured cognitive reflection journal. As a result, we found that the well-structured cognitive reflection journal affects learners positively in the sense of metacognition ability, continuity as well as learning achievement.

• Journal of The Korean Association of Information Education
• /
• v.20 no.5
• /
• pp.465-474
• /
• 2016

The present study is aimed to find the effect of the activity of writing a structured reflection journal in the learning process of PBL-based programming on the logical thinking of elementary school students. To achieve the objective, this study carried out an experiment with 59 elementary school students in the 5th grade. They were divided into an experimental group and a control group. The experimental group was applied with PBL-based programming classes by learning step, including learning of the contents, its procedure, and the activities of writing a critical reflection journal while the control group received learning of PBL-based programming including unstructured reflection journal. And then the difference in their logical thinking was compared and analyzed before and after th experiment. The results demonstrated that the experimental group showed a significant difference in logical thinking before and after writing structured reflection journal (ANCOVA) at the significance level of .05, which evidenced writing a structured reflection journal has learning effect. Intergroup comparison of logical thinking also showed that there was learning effect. Those findings suggest that writing a structured reflection journal in the PBL-based programming learning for 5th grade elementary school students has a positive effect on the learners' logical thinking.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.14 no.4
• /
• pp.274-281
• /
• 2002

Numerical analysis for the Bragg reflection due to a sinusoidally and a doubly-sinusoidally varying seabeds was performed by using a couple of ordinary differential equations derived from the Boussinesq equations. Incident waves are a train of cnoidal waves. The effects of the dispersion and shape of seabed were investigated. It is shown that the reflection of a sinusoidally varying seabed is enhanced by increasing the dispersion and the amplitude of a seabed. The reflection of waves over a doubly-sinusoidally varying seabed can also be enhanced by increasing the amplitude of seabed decreasing the difference of wave numbers of seabed components.

• Korean Journal of Optics and Photonics
• /
• v.23 no.1
• /
• pp.36-41
• /
• 2012

Total external reflection (TER), which does not occur on a dielectric interface, is a unique feature of surface plasmon-polaritons (SPP). We propose an SPP-TER waveguide structure consisting of low-index dielectric nanocore covered with high-index dielectric on a flat metal surface. The SPP mode confined in the nanocore by the TER effect has a mode size much smaller than wavelength scale. Numerical comparison of mode characteristics between the SPP-TER waveguides and other total-internal-reflection-based waveguides such as metal or high-index dielectric nanowires show that the SPP-TER structures can possess higher modal gain for applications of nanocavity lasers.

• Journal of Korea Water Resources Association
• /
• v.33 no.6
• /
• pp.805-814
• /
• 2000

A numerical model based on the boundary element method is employed to describe diffraction of monochromatic water waves due to varying topographies. The model is firstly verified by comparing obtained reflection and transmission coefficients of waves over a trench to those of the eigenfunction expansion method. The model is then used to investigate the Bragg reflection of waves over sinusoidally varying topographies. Calculated reflection coefficients are compared to available laboratory measurements and semi-theoretical results. A reasonably good agreement is observed.served.

• Journal of Korea Water Resources Association
• /
• v.36 no.3 s.134
• /
• pp.413-422
• /
• 2003

Numerical analysis for the Bragg reflection due to sinusoidally varying seabeds tying on a sloping beach was performed by using a couple of ordinary differential equations derived from the Boussinesq equations. Incident waves were wane groups generated by two short waves with slightly different phases. Effects of the slope of a seabed to the reflection were investigated in detail. It is shown that the reflection of long waves enhanced by increasing the slope of a seabed. This phenomenon caused by increase of wave amplitude due to increase of nonlinearity and shoaling.

• Journal of Korea Water Resources Association
• /
• v.36 no.3 s.134
• /
• pp.447-454
• /
• 2003

The Bragg reflection of monochromatic waves propagating over a rectangular-typed impermeable submerged breakwaters is numerically investigated by using the finite element method. The reflection coefficients calculated from the present model are compared with those of laboratory measurements and the eigenfunction expansion method. A good agreement is observed. The finite element model is also applied to calculate reflection coefficients according to variations of length and width of submerged breakwater.