• The Journal of Advanced Prosthodontics
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• v.2 no.3
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• pp.81-87
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• 2010

PURPOSE. The purpose of this study was to compare the linear sintering behavior of presintered zirconia blocks of various densities. The mechanical properties of the resulting sintered zirconia blocks were then analyzed. MATERIALS AND METHODS. Three experimental groups of dental zirconia blocks, with a different presintering density each, were designed in the present study. Kavo $Everest^{(R)}$ ZS blanks (Kavo, Biberach, Germany) were used as a control group. The experimental group blocks were fabricated from commercial yttria-stabilized tetragonal zirconia powder (KZ-3YF (SD) Type A, KCM. Corporation, Nagoya, Japan). The biaxial flexural strengths, microhardnesses, and microstructures of the sintered blocks were then investigated. The linear sintering shrinkages of blocks were calculated and compared. RESULTS. Despite their different presintered densities, the sintered blocks of the control and experimental groups showed similar mechanical properties. However, the sintered block had different linear sintering shrinkage rate depending on the density of the presintered block. As the density of the presintered block increased, the linear sintering shrinkage decreased. In the experimental blocks, the three sectioned pieces of each block showed the different linear shrinkage depending on the area. The tops of the experimental blocks showed the lowest linear sintering shrinkage, whereas the bottoms of the experimental blocks showed the highest linear sintering shrinkage. CONCLUSION. Within the limitations of this study, the density difference of the presintered zirconia block did not affect the mechanical properties of the sintered zirconia block, but affected the linear sintering shrinkage of the zirconia block.

• Bulletin of the Korean Mathematical Society
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• v.43 no.3
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• pp.619-626
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• 2006

Let m be any positive integer, R be a ring with identity, $M_m(R)$ be the matrix ring of all m by m matrices eve. R and $G_m(R)$ be the multiplicative group of all n by n nonsingular matrices in $M_m(R)$. In this pape., the following are investigated: (1) for any pairwise coprime ideals ${I_1,\;I_2,\;...,\;I_n}$ in a ring R, $M_m(R/(I_1{\cap}I_2{\cap}...{\cap}I_n))$ is isomorphic to $M_m(R/I_1){\times}M_m(R/I_2){\times}...{\times}M_m(R/I_n);$ and $G_m(R/I_1){\cap}I_2{\cap}...{\cap}I_n))$ is isomorphic to $G_m(R/I_1){\times}G_m(R/I_2){\times}...{\times}G_m(R/I_n);$ (2) In particular, if R is a finite ring with identity, then the order of $G_m(R)$ can be computed.

• Journal of Fashion Business
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• v.13 no.4
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• pp.178-190
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• 2009

The purpose of this study is to make reference for geometric fashion by investigating geometric patterns by linear types and to propose high value added print and fashion design by designing and producing geometric prints and apparel with them focusing on digital textile printing. As a method of the study, visual and textural data were investigated for theory of geometric pattern and fashion design samples were illustrated. The geometric pattern could be defined as abstract pattern which was crossed with straight line or curve. We could group it into three classes such as straight linear, curved, and mixed type. Images varied with linear types. The image of straight linear type was sharp and modern, that of curved one was soft and feminine and that of mixed one was gorgeous and artistic. And then, 3 geometric prints and 3 one-pieces were designed. The concept of design was simple optimism which was based on sixties. Target was young optimistic women group from the mid teens to the mid twenties who continued to seek after their unique individuality keeping their modern lifestyle. Geometric patterns with straight linear, curved, and mixed type were designed and dresses which went well with them were designed and produced. According to the result of this study, images of geometric fashion can be represented diversely by varying linear type, digital textile printing is good method for high value added geometric fashion because of its high quality and degree of sensitivity, and geometric pattern is a good source for contemporary fashion.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.121-129
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• 2013

PURPOSES : This study deals with the traffic accidents of rotary in Korea. The objective of this study is to develop the accident models by age group based on the various data of rotaries. METHODS : In pursuing the above, this study gives particular attentions to classifying the accident data of 17 rotaries by age, collecting the data of geometric structure, traffic volume and others, and developing the models using SPSS 17.0 and EXCEL. RESULTS : First, 3 multiple linear regression models which were all statistically significant were developed. The value of model of under 30-49 age group were, however, evaluated to be 0.688 and be less than those of other models. Second, the most powerful variables were analyzed to be traffic volume in the model of under 30 age group, circulatory roadway width in the model of 30-49 age group, and the number of approach lane in the model of above 50 age group. Finally, the test results of accident models using RMSE were all evaluated to be fitted to the given data. CONCLUSIONS : This study propose install streetlights, speed humps and widen Circulatory as effective improvements for reduction of accident in rotary.

• East Asian mathematical journal
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• v.6 no.2
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• pp.223-230
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• 1990

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.4
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• pp.71-80
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• 2007

The purpose of this study is to suggest the criteria for the damaged mountainous landscape based on the shape, location and ratio of damaged landscape. For the study, the preference and landscape adjectives were analyzed on visual images and simulations. The variables for analysis were the amount of the damaged ratio(10%, 30%, 50%), the location of the damage (upper, middle, lower) and the various forms of the damage(spot, line, area). According to the results of this study, in accordance with the amount of damage, the visual preference recorded its lowest with the a rate of 50%. As for the location of the damage, the lower-ridge of the mountain showed the highest preference, and the upper-ridge was recorded as the lowest. The linear damage type showed the highest preference. On the other hand, the spotted damage type showed lowest. The results indicate that the visual preference increases when there is a lower ratio of damage, as the damage locates at the lower-ridge, and also when there is a presence of linear formation development. The group of linear formation-the lower ridge-10% showed the highest preference, and the group of linear formation-the mid ridge-50% was the lowest with the results of 3-way ANOVA. The group of linear formation-lower ridge-10% in particular had virtually no differences of visual preference when it was compared with the original scene. The damage with the spotted formation, on the mid-upper location and the high ratio of damage were analyzed as factors that give negative influence on the mountainous landscape. The main features of mountainous landscape were reduced into two factors, 'total estimation' and 'spatial scale' by the factor analysis with total variance of 65.96%.

• Journal of the Korean Society of Safety
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• v.25 no.2
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• pp.84-88
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• 2010

The main point of this study is to find ways to prevent accidents at complex linear sections in advance by improving geometric structure elements that can be considered from the designing stage. Complex linear roads are consisted of sections where straight sections connect with curved sections or sections where curved sections connect with curved sections with relatively high possibility of accidents and accidents can be reduced through improving designing elements in these sections. Therefore, this study aims to develop accident forecasting model in complex linear roads and to clarify major elements affecting traffic accidents. The results of analysis showed that the groups are divided into a group less than 355m based on curve radius of 355m, a group whose curve radius exceeds 355m and a group whose incline exceeds -0.79 and a group whose curve radius is below 355m and incline exceeds -0.79 for straight section + curved section, and for curved section + curved section, it is divided into a group whose first curved section is less than 410m based on curve radius of 410m and the first curve is turning right and a group exceeding 410m and the first curve is turning left. The major variables common in 2 models are front curve radius and curve types(left, right), road surfaces, weather.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.965-969
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• 2003

In this paper, the implementation technique of digital crossover network using perfect linear phase IIR filters is presented. This system has various advantages which cannot be obtained from analog crossover network such as linear phase response, flat group delay and sharp cut-off at low-order over audio frequency band. The simulation results show that the group delay response is maximally flat and twice more attenuation in stop-band than the prototype elliptic IIR filter at all desired frequency.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.4
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• pp.168-173
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• 2012

The aggregation of group loads, which consists of the linear and the non-linear systems, yields the error involved in the reactive power aggregation, which is greater than the active power aggregation in the component based load modeling. Each individual reactive power in a group load affects the aggregated load different from composition rate. This paper proposes a new method that determines the degree of impacts by adjusting the coefficient of weight factors of each load using the least squares error method. The effectiveness of proposed algorithm is demonstrated by simulating three aggregation cases.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.47.1-47.1
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• 2019

We report the design and vibration analysis for the optomechanical structures of Linear Astigmatism Free - Three Mirror System (LAF-TMS). LAF-TMS is the linear astigmatism free off-axis wide-field telescope with D = 150 mm, F/3.3, and FOV = 5.51° × 4.13°. The whole structure consists of four optomechanical modules. It can accurately mount mirrors and also can survive from vibration environments. The Mass Acceleration Curve (MAC) is adapted to the quasi-static analysis. Modal, harmonic, and random vibration analysis have been performed under the qualification level of the launch system. We evaluate the final results in terms of von Mises stress and Margin of Safety (MoS).