• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.22-22
• /
• 2009

The silver thick film has been used in many industries such as display, chip, solar cell, automobile, and decoration with conventional heating. The silver thick film is fired with optimal time and temperature. However, decreasing the fabrication time is required due to high production power. Furthermore, there is a problem that silver in electrode is diffused throughout any substrates. For inhibiting the Ag diffusion and long fabrication time we considered a microwave heating. We investigated firing of silver thick film with conventional and microwave heating. The temperature of substrate was measured by thermal paper and the temperature of substrate was under $100\;^{\circ}C$ The shrinkage of electrode was measured with optical microscopy and optical profilometry. The shrinkage of electrode heat treated with microwave for 5min was similar to the that fired by the conventional heating for several hours. After firing by two types of heating, the diffusion of silver was determined using a optical microscope. The microstructure of sintered silver thick film was observed by SEM. Based on our results, the microwave heating should be a candidate heating source for the fabrication electronic devices in terms of saving the tact time and preventing the contamination of substrate.

• Wind and Structures
• /
• v.34 no.1
• /
• pp.59-72
• /
• 2022

In this work the numerical results of the flow around a 5:1 rectangular cylinder at Reynolds numbers 3 000 and 40 000, zero angle of attack and smooth incoming flow condition are presented. Implicit Large Eddy Simulations (ILES) have been performed with a high-order accurate spatial scheme and an implicit high-order accurate time integration method. The spatial approximation is based on a discontinuous Galerkin (dG) method, while the time integration exploits a linearly-implicit Rosenbrock-type Runge-Kutta scheme. The aim of this work is to show the feasibility of high-fidelity flow simulations with a moderate number of DOFs and large time step sizes. Moreover, the effect of different parameters, i.e., dimension of the computational domain, mesh type, grid resolution, boundary conditions, time step size and polynomial approximation, on the results accuracy is investigated. Our best dG result at Re=3 000 perfectly agrees with a reference DNS obtained using Nek5000 and about 40 times more degrees of freedom. The Re=40 000 computations, which are strongly under-resolved, show a reasonable correspondence with the experimental data of Mannini et al. (2017) and the LES of Zhang and Xu (2020).

• Journal of Communications and Networks
• /
• v.1 no.3
• /
• pp.145-152
• /
• 1999

A new switch architecture is presented to enhance out-put queuing in photonic packet switches. Its appkication is for a packet switching enviroment based on the optical transport of fixed length packets. This architecture consists of a couple of cas-cading switching elements with output queuing, whose buffer ca-pacity is limited by photonic technology. The introduction of a suitable buffer management allows a very good and balanced ex-ploitation of the available optical memories, realized with fiber de-lay lines. In particular, packet loss performance is here evaluated showing the improvement with respect to the single switch and a way to design large optical switches is shown in order to meet broadband network requirements.

• Journal of the Korean Geographical Society
• /
• v.35 no.1
• /
• pp.95-120
• /
• 2000

구성주의 수업은 삶의 경험 혹은 나의 문제로 전환된 문제를 학습주제로 하여, 교사와 학습자, 학습자간에 상호성과 상보성이 전제된 대화화 협력을 통해, 맥락에 적합한 지식을 구성하는 활동이라 할 수 있다. 구성주의 지리교육은 지리학을 위해 지리적 지식을 구성하는 것이 아니라, 지리적 삶을 위해 지리적 지식을 구성하는 것이다. 이것은 지리적 맥락과 맥락의 구성에 충실할 때 가능해 진다. 방법론적으로는 생활 주변에서 볼 수 있는 지리적 사상을 학습대상으로 하여, 이들을 그림이라는 상징을 통해 학습자 스스로 맥락에 따라 구성, 재구성하는 과정 속에 지리적 지식이 구성되게 하는 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.8
• /
• pp.1368-1387
• /
• 2011

In recent years, ubiquitous and pervasive scenarios have emerged as a complex ecosystem where differentiated software/hardware components interoperate wirelessly and seamlessly. The goal is to enable users to continuously access services and contents, and to always get the best out of their current environment and available resources. In such dynamic and flexible scenarios, the need emerges for flexible and general solutions for continuous runtime self-reconfiguration and self-optimization of ubiquitous support software systems. This paper proposes a fully reconfigurable middleware approach that aims at reconfiguring complex software systems made up of heterogeneous off-the-shelf components from both functional and non-functional perspectives. Our middleware can also extend already existing and non-reconfigurable middleware/applications in an easy and flexible way, with no need to re-design them. The proposed design principles have been practically applied to the implementation of a runtime self-reconfigurable middleware called Off-The-Shelf Ready To Go (OTS-RTG), implemented on top of iPOJO. The reported experimental results both exhibit a limited overhead and show the wide applicability of the proposed solution to many application scenarios, including complex, industrial, Enterprise Service Bus-based ones.

• Korean Institute of Interior Design Journal
• /
• no.39
• /
• pp.100-107
• /
• 2003

The purpose of this study is to help create environments for early childhood education according to the principles of Constructivism. Generally, preschools in Ulsan Metropolitan City were used as samples for this study More particularly, 116 kindergartens were surveyed by telephone to evaluate their education programs. Four kindergartens that completely or partially used Constructivism in their programs were chosen as primary subjects for this study The results of this study were as follows: First, it was discovered that preschool education in Ulsan uses an integrated education model based on activities and Montessorie. Constructivist programs were also present using Project Approach, Reggio Emilia and Piaget. Second, the number of infants per class averaged 29.3. The average infants per playroom was 2.38$m^2$. It seems, therefore, that there is a lack of sufficient space for activities. Playroom furniture is primarily used for storage and it lacks variety and flexibility of use. The interior of preschools in related to materials, color and images also showed little difference among schools. Third, it was found that virtually every play space did not have adequate water playing and sand playing sections. Instead, the space for the large-muscle activities of big groups was used for this purpose. Fourth, kindergartens that use the principles of Constructivism plan to specialize their activities. Those only partially using Constructivism showed conventional tendencies and small play spaces that would be defined as inadequate according to Constructivism. This study, therefore, demonstrates that preschool education based on Constructivism are not being well-implemented in concert with other programs.

• International Journal of Computer Science & Network Security
• /
• v.22 no.7
• /
• pp.123-130
• /
• 2022

Researchers had theorized that the earliest years' experiences were extremely critical to a child's future development (Jung, 2008; Liu et al., 2020), and parental involvement was a key character (Lamb et al., 2002; Liu, 2020). Though the critical role of parental involvement in education has been confirmed, less attention has been paid to its influence on infants' development. For the sake of infants' appropriate development, infant teachers always met barriers to finding, designing, and implementing age-appropriate activities. This case study aims at exploring the role of parental involvement in the development in infancy by surveying one director, four infant teachers, and six early childhood pre-service teachers' perspectives and practices regarding parental involvement in infant rooms within a Reggio Emilia-inspired child development center. Findings revealed that all participants: (1) thought parental involvement was essential to their decision-making process; (2) were aware of the benefits of implementing parental involvement in infants' rooms; (3) gained an opportunity to reflect on their practices regarding parental in-volvement and reprocess their previous perspectives. This study recommends that, in order to facilitate infants' development appropriately, child-care centers need to take into account parental involvement and work with parents collaboratively.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.7
• /
• pp.1104-1110
• /
• 1999

We condicted two experiments to evaluate the interaction among fumaric acid (FA), protected acids (PA), or no additional acid (NO) and two different levels of acid buffering capacity (BC) in diets for 14-d-old weaned pigs. BC was varied substituting mono-calcium phosphate and calcium sulfate for dicalcium phosphate and calcium carbonate. In the high BC diet plus PA, FA was also added. In Exp. 1, 48 gilts were raised for 31 days on the six diets, evaluating growth performance and fecal digestibility. In Exp. 2, 42 gilts were raised. With each diet three subjects were sacrificed after 19 days and four after 38 days. In addition, six subjects were sacrificed at weaning. Growth and carcass performance, ileal digestibility, bacterial populations and pH in the gut were assessed. The piglet performance and stomach, ileal and cecal pH, and empty body composition were not affected by the diets. Empty body composition other than ash content was affected by piglet age (p<0.01). The BC did not influence digestibility. The dietary inclusion of PA improved fecal digestibility of protein (p<0.05) compared to the addition of FA and NO. Ileal digestibility slightly increased with both acid additions (p<0.10), the groups receiving PA showing the higher values. Piglets fed diets with low BC had lower Lactobacillus and E. coli counts in the ileum (p=0.07) and higher Lactobacillus in the colon (p=0.08). Acidified diets tended to reduce E. coli counts in the ileum (p=0.10) and increased Lactobacillus in the colon (p=0.09). The addition in the diet of PA increased Lactobacillus in the ileum compared to the sole addition of free fumaric acid (p=0.07). The addition of protected acids, combined with free fumaric acid in the case of high BC diets, increased protein digestibility and Lactobacillus counts and reduced E.coli counts. Only some changes in the concentration of bacterial population can be expected with a diet of low BC.

• Korean Journal of Radiology
• /
• v.2 no.4
• /
• pp.210-215
• /
• 2001

Objective: To investigate the efficacy of gadobenate dimeglumine (GdBOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. Materials and Methods: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of GdBOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. Results: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. Conclusion: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.1
• /
• pp.343-351
• /
• 2021

The aim of this study is to explore the role of teachers in the 2019 revised Nuri curriculum, to suggest the role of appropriate early childhood teachers, and to explore the possibility of developing as an emerging curriculum. It was clarified that the role of teachers in the 2019 revised Nuri curriculum is the applicant, compared to the Nuri curriculum by age 3~5. It could be compared with the role of teachers in the emergent curriculum. Based on the emerging curriculum, the roles of teachers that can be practiced in the 2019 revised Nuri curriculum are teachers who use scaffolding, flexible teachers in curriculum management, and teachers with autonomy and faith in young children. As a conclusion of the study, first, teachers should be experts who can provide optimal play materials to individual young children and multiple young children. Second, teachers must faithfully observe and record so that appropriate scaffolding can be established. Third, teachers must constantly perform questions suitable for development so that they can sustain the interests of young children. Fourth, teachers should operate the 2019 revised Nuri curriculum based on their understanding of the emergent curriculum.