• Journal of The Korean Association of Information Education
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• v.20 no.2
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• pp.189-196
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• 2016

The PATROL instructional model only uses digital textbooks. PATROL is an acronym for Planning, Action, Tracking, Recommending, Ordering, and Leading. Teachers have a difficult time using current digital textbooks to determine how much time students spend using course materials. This is because current digital textbooks can only show the content of paper textbooks and display additional multimedia materials. In this study, digital textbook functions were designed based on the PATROL model in order to analyze students' learning situations, diagnose problems, and offer solutions. Digital textbook are based on learning analytics named SEE-PAD. SEE-PAD is composed of the following: Social network analysis; Evaluation and assEssment analysis; Predictive analysis; Adaptive learning analysis; and the analysis Dashboard. I drew and showed the use case and sequence diagrams of SEE-PAD to help design digital textbook functions.

• Journal for History of Mathematics
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• v.21 no.2
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• pp.71-80
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• 2008

From the ancient Korea, our ancestor had designed the unique pattern which is Dan-chung, in architectures such as palace and Buddhist temple. In Dan-chung pattern, there are many various kinds, that is geometric pattern, arabesque pattern, plant pattern, flower pattern, animal pattern, Buddhist pattern and living pattern. So, we can see the tessellations in the Dan-chung pattern, moreover we can find the beauty of tessellation in the Korean traditional architectures and crafts. In this paper, I'll show you Korean traditional tessellations via GSP 4.0. which means geomeric program Geometer's SkechPad.

• Journal of the Korea Computer Industry Society
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• v.9 no.2
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• pp.93-98
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• 2008

In this study, analyzed principle about stream cipher that is formed to Cellular Automata foundation. Cellular Automata can embody complicated and various principle with simple identifying marks that is State, Neighborhood, Transition Rules originally. Cellular Automata is hinting that can handle encipherment smoothly using transition rule. Create binary pad (key stream) by Cellular Automata's transition rule 30 applications in treatise that see therefore, and experimented ability of encryption and decryption because using stream cipher of symmetric key encryption way of password classification.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.761-769
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• 2022

Pads with high dielectric materials have been used in a variety of applications to locally improve the field sensitivity and homogeneity of RF pulses in clinical MRI studies. In this study, we aimed to improve such pads in consideration of the practical problems associated with the application of actual clinical images. A high permittivity pad to increase the attenuated B1 field strength was fabricated and tested in 7T MRI. Sim4Life simulation and experimental results show stronger and relatively uniform B1 near field. In order to improve the image quality in the whole cerebellum, known as a region with low sensitivity, a guide was made to reduce the mechanical change of the pad. In order to improve the wearing comfort, the pad was designed by dividing it into upper and lower parts. The facial pad showed an overall signal increase effect in areas such as the turbinate in the nasal cavity. Signal increase was expected in areas such as the frontal lobe and eyes, but the effect was either insignificant or it was difficult to see the effect in the imaging protocol. In conclusion, this paper showed a cerebellar-optimized pad with an improved nasal signal while maintaining its effectiveness.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.692-696
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• 2011

A clutch is a very important component when engine starts and gear shifting is needed. The clutch the most commonly used is the dry clutch. This type of clutch has pads, and they are worn after disengagement of clutch little by little. The characteristics of the clutch changes as these pads wear, so wear needs to be measured, and the clutch should be controlled for proper operation. In this study, the clutch contact point estimation algorithm has been developed. From this algorithm, clutch force map changes depending on wear, and the clutch operates properly. We also see the shifting transient of a vehicle for drivability with throttle valve position control and synchronizer movement.

• Elastomers and Composites
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• v.35 no.2
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• pp.138-148
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• 2000

In order to investigate the possibility of EPDM micro cellular pad (MCP) as an impact sound insulation product, we studied static/dynamic properties and vibration transfer characteristics of EPDM MCP depending on shape, thickness, degrees of foaming by using material test system (MTS) and lab scale mock-up test apparatus. Static/dynamic rigidity is increased when shape is simple. thickness and degrees of foaming low. We could see that dynamic stiffness is proportional to the transmissibility of EPDM MCP. When dynamic stiffness is increased, characteristic peak at transmissibility curve moves high frequency range or snows increase of maximum value of transmissibility. For lab scale mock-up test and finite element method, EPDM MCP shows low vibration velocity and superior mode shape to just concrete plus slab structure. We could confirm that possibility of EPDM MCP as a impact sound insulation product is high.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.31-36
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• 2018

This research scrutinizes the reason of failure after pressure cooker test (PCT) for DRAM device. We use the physical inspecting tools, such as microscope, SEM and TEM, and finally find the discolor phenomenon, corrosion of Al and delamination of inter-metal dielectric (IMD) in the failed devices after PCT. Furthermore, we discover the abnormal $Al_XO_Y$ layer on Al through the careful additional measurements. To find the reason, we evaluate the effect of package ball size and pinhole in passivation layer. Unfortunately, those aren't related to the problems. We also estimate halide effect of Al. The halogens such like Cl are contained within EMC material. Those result in the slight improving of PCT characteristics but do not perfectly solve the problems. We make a hypothesis of Galvanic corrosion. We can find the residue of Ti at the edge of pad open area. We can see the improving the PCT characteristics by the time split of repair etch. The possible mechanism of the PCT failure can be deduced as such following sequence of reactions. The remained Ti reacts on the pad Al by Galvanic corrosion. The ionized Al is easily react with the $H_2O$ supplied under PCT environment, and finally transfers to the abnormal $Al_XO_Y$ layer.

• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.121-131
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• 1999

Recently our educational methodologies have been changed to an open, student-centered structure. Mathematics is now learned through experiential interaction and less emphasis is placed on abstract theories. For example, the axioms of the geometry in the middle school curriculum have been expressed by using symbolic letters. Students find these abstractions very difficult and it hinders their ability to grasp the significance of geometrical concepts. In an effort to simplify these abstract concepts and enhance the students interest and ability to learn, the GSP (Geometry Sketchpad) is proving to be a useful and effective tool. First, Second and third grade students have found the GSP to be extremely useful. While the pad has no sound function it still enables the students to freely change diagrams without disrupting the integrity of the program. There is also a running order of instructions at the bottom of the screen to facilitate the step by step understanding of mathematical procedures. This function makes the program ideal for use by teachers, students and even beginners. Anyone experiencing difficulty can get immediate assistance from the guidebook which is located at the back of each program. Allowing individuals to manipulate and actually see the changing deductions and axiom proofs on the computer screen provides them with immediate feedback and reinforcement. It also enhances their overall interest in learning geometry. The use of the GSP is proving to be an innovative and effective tool in facilitating the transition of mathematics into an open, student-centered educational forum.

• Toxicological Research
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• v.34 no.2
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• pp.163-172
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• 2018

Air pollution is increasing, along with consumption of fossil fuels such as coal and diesel gas. Air pollutants are known to be a major cause of respiratory-related illness and death, however, there are few reports on the genotoxic characterization of diverse air pollutants in Korea. In this study, we investigated the mutagenic activity of various particles such as diesel exhaust particles (DEP), combustion of rice straw (RSC), pine stem (PSC), and coal (CC), tunnel dust (TD), and road side dust (RD). Ultra-fine particles (UFPs) were collected by the glass fiber filter pad. Then, we performed a chemical analysis to see each of the component features of each particulate matter. The mutagenicity of various UFPs was determined by the Ames test with four Salmonella typhimurium strains with or without metabolic activation. The optimal concentrations of UFPs were selected based on result of a concentration decision test. Moreover, in order to compare relative mutagenicity among UFPs, we selected and tested DEP as mutation reference. DEP, RSC, and PSC induced concentration-dependent increases in revertant colony numbers with TA98, TA100, and TA1537 strains in the absence and presence of metabolic activation. DEP showed the highest specific activity among the particulate matters. In this study, we conclude that DEP, RSC, PSC, and TD displayed varying degrees of mutagenicity, and these results suggest that the mutagenicity of these air pollutants is associated with the presence of polycyclic aromatic hydrocarbons (PAHs) in these particulate matters.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.3
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• pp.169-183
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• 2004

This study attempts to understand women's underwear culture in the Later Chosun Dynasty, by investigating the kinds and constructions of them, which formed bulky and puffed silhouette of the lower half of the body. In the middle 17th century in Chosun, Confucianism settled down as fundamental idea of society, while whole country achieved considerable economic growth. As a result for upperclass women, female virtues was demanded more than any other period in Chosun. On the other hand, lower-class women including Kisaengs, had more freedom on their clothing behaviors. According to the literature on women's dress institutions and restrictions of the extravagance, the use of kinds of high-quality silk and false hair was criticized, compared to women's clothes in China. From this, one can see the luxury and affluence of women's clothes at that time, which also reflected in luxurious underclothes. Also, the movement of class, by economic development, led to changes in the costumes of middle-to-lower class women, relaxing restrictions on clothes. Underclothes included Bosomband(가슴띠; long sashes for bosom to wrap), Sokjucksam(속적삼), and Sokchogori(속저고리; Korean blouse, worn under the chogori) for upper garment, and Darisokkok(다리속곳; basic underwear like the panty), Soksokkot(속속곳; underwear paji to be wide of hem), Sokpaji(속바지;trouser front and back opening), Tansokkok(단속곳; large size underwear like Soksokkot), Noronpaji(너른바지; paji like the skirt or paji bulky than tansokkot,), Mujigi무지기; tiered skirt for underwear), and Daeshumchi'ma(대슘치마; Korean underskirt, shape hem as a pad into form) for lower clothes.