• Journal of the Korea Computer Graphics Society
• /
• v.17 no.4
• /
• pp.31-40
• /
• 2011

Projector-based visual systems are widely used for VR and experience display applications. But the illumination irregularity on the screen surface due to the screen material and its light reflection properties sometimes deteriorates the user experience. This phenomenon is particularly troublesome when the participants of the head tracking VR system such as CAVE or the motion generation experience system continually move around the system. One of reason to illumination irregularity is projector-screen specular reflection component to participant's eye's position and it's analysis needs high computation complexity. Similar to calculate specular lighting term using GPU's programmable shader, Our research adjusts every pixel's brightness in runtime with given 3D screen space model to reduce illumination irregularity. For doing that, Angle-based brightness compensate function are considered for specific screen installation and modified it for GPU-friendly compute and access. Two aspects are implemented, One is function access transformation from angular form to product and the other is piecewise linear interpolate approximation.

• Journal of the Korea Concrete Institute
• /
• v.23 no.5
• /
• pp.667-674
• /
• 2011

This paper discusses the analysis method of prestressed concrete girder integral abutment bridges for a 75-year bridge life and the development of prediction models for abutment displacements under thermal loading due to annual temperature fluctuation and time-dependent loading. The developed nonlinear numerical modeling methodologies considered soil-structure interaction between supporting piles and surrounding soils and between abutment and backfills. Material nonlinearity was also considered to simulate differential rotation in construction joints between abutment and backwall. Based on the numerical modeling methodologies, a parametric study of 243 analysis cases, considering five parameters: (1) thermal expansion coefficient, (2) bridge length, (3) backfill height, (4) backfill stiffness, and (5) pile soil stiffness, was performed to established prediction models for abutment displacements over a bridge life. The parametric study results revealed that thermal expansion coefficient, bridge length, and pile-soil stiffness significantly influenced the abutment displacement. Bridge length parameter significantly influenced the abutment top displacement at the centroid of the superstructure, which is similar to the free expansion analysis results. Developed prediction model can be used for a preliminary design of integral abutment bridges.

• Journal of the Korean Ceramic Society
• /
• v.19 no.2
• /
• pp.133-138
• /
• 1982

Two kinds of clinker liquid melts, one containing 2.0% of $K_2O$ and the other without $K_2O$, were prepared with the similar composition as those developed during the firing of portland cement clinker. One portion of melt was quenched and found to consist of glass together with traces of proto-$C_3A$, and the other portion was allowed to cool spontaneously to crystallize $C_3A$ and calciumferrite well. The product obtained by crystallization of the melt without $K_2O$showed cubic $C_3A$, while orthorhombic $C_3A$ was formed from the crystallized product containing $K_2O$. Studies on the hydration behavior of the samples made from the melts with 30% of gypsum were carried out for 24 hours by observation at regular intervals ettringite, monosulphate hydrates and gypsum which were formed or consumed during hydration. The samples without $K_2O$ in the melts were hydrated wth addition of proper amount of $K_2SO_4$ in the water for hydration. Hydration behavior of glassified $C_3A$ showed that it has low reactivity relative to crystallized $C_3A$, and also hydration reactivity of orthorhombic $C_3A$ was much lower than that of cubic $C_3A$ in 60 minutes. Potassium sulphate in the solution reduced the hydration reactivity of $C_3A$ . Evolution peaks of hydration heat examined by twin-type conduction micro-calorimeter showed that glassified $C_3A$ without $K_2O$ had secondary peak after 9 hours and $C_3A$ containing $K_2O$ after 12 hours. When crystallized $C_3A$ was hydrated, initial peaks of hydration heat were considerably high and there was no secondary peak for cubic $C_3A$ but the secondary peak of orthorhombic $C_3A$ appeared after 4 hours.

• Journal of the Korean GEO-environmental Society
• /
• v.10 no.4
• /
• pp.41-48
• /
• 2009

A flexible pipe was buried 10cm below the ground formed with standard sand to observe changes in the shape of the pipe according to the behavior of ground at each relative density. Changes in the shape of the pipe in each ground were observed to examine the behavior of the pipe under the state of reinforced ground after installing geogrid under the pipe. Ground reinforced using geogrid formed tensile force on the reinforcement material with increase in the vertical load and showed reduction in settlement under identical vertical load with existence of reinforcement. Distributions of ground deformation of 100% relative density and 70% relative density had clear difference. Reinforced ground with 70% density converged to the ground reaction of final settlement of non-reinforced ground with 100% density at final settlement of 100 mm. Because the shape of lower part strain of the buried pipe is similar to that of un-reinforced ground with relative density of 100%, reinforcement effect by geogrid in soft ground can be anticipated.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.1
• /
• pp.53-59
• /
• 2010

In seawater deposition condition, the corrosion and chemical attack of grouts are similar to those of concrete structure. Used in domestic MSG (Micro Silica Grouting) mixtured large amounts of silicate materials containing as cement powder is $8,000cm^2/g$ of the specific surface area or more due to the high hydration activity and high-strength, high durability, and features, $C_3A$ content of less than 5% to meet the standards chemical attack of seawater was evaluated as a cement material. Therefore, in this paper, with excellent seawater attack resistant MSG in combination with rapid hardening mineral was used, those of seawater characteristics were evaluated experimentally. Typically, sodium-silicate minerals or rapid hardening cements are used in domestic. About the homogel specimens with combination of MSG and rapid hardening agents for compressive strength, weight and length change characteristics were evaluated experimentally, and so we could present the excellent seawater resistant grouts combination.

• Journal of the Korean Geosynthetics Society
• /
• v.11 no.3
• /
• pp.37-42
• /
• 2012

The cement paste is mostly used as the filling materials of bored pile in Korea. The use of filling material based on cement paste is inefficient at field construction because it needs a lot of the charging mass. In addition, it has environmental problem according to the large amount of cement use because its strength is also larger than criterion. The excavated soil with stabilizer can be used as the filling materials when the bored pile is constructed. Therefore, this paper describes field application of solidified soil for economical efficiency and environment-friendly. The injection capacity of solidified soil is compared with cement paste's based on unconfined compressive strength test and field load test, and the appropriate of test results is evaluated by design criterion. The evaluation result shows that the capacity of excavated soil with stabilizer is similar to cement paste and the solidified soil is able to apply as filling materials of bored pile because it is satisfied with design criterion.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2000.11b
• /
• pp.91-95
• /
• 2000

With 106 detached houses where the aged people live alone, this study was conducted to perform a location survey of their residential environment. The result of this study is summarized as follows: While the surveyed houses' safety, sanitation and convenience appeared to be positive, with respect to the conditions of location, 73％ of the surveyed houses did not meet the requirement for comfort. The average area of each space indicated that the bedding room was 12.05$m^2$, the living room 14.71$m^2$, the kitchen 9.06$m^2$, the bathing room 4.05$m^2$, and the rest room 2.59$m^2$. Then, 93.3％ of the bedding rooms had the doorsill. Also, 97.2％ of the surveyed houses had retrievable space. The form of their living room door showed a hinged door(54.5％) and a sliding door(45.5％) which were similar with each other. The finished material was that wood accounted for 42.6％ which was highest. The cooking table form of kitchen was mainly "\ulcorner"-shaped(49.5％) and "\ulcorner"-shaped(48.5％) which were highest, and their average height appeared to be 815mm. The fuel used for kitchen was that gas accounted for 93.3％, while 95.2％ of the surveyed houses was not equipped with any gas-warning device. 75.5％ had an integrated type of bath room and toilet. In addition, the stepped difference between the bath room and other space was that 70.8％ had the difference, but they had no a satisfactory sliding-prevention device(Not for 91.6％) or heating system(Not for 92.9％).stem(Not for 92.9％).

• Journal of the Korea Fashion and Costume Design Association
• /
• v.14 no.3
• /
• pp.23-36
• /
• 2012

The purpose of this study was to identify the status of fashion related subjects in colleges and to utilize it as a basic material to develop a better curriculum. To do this, 43 2-year colleges or 63 majors in Korea were analyzed. From the analysis of the locations of the colleges with fashion related majors, it was found that 51.2% schools with fashion related majors were located in the Capital area. When looking at the division to which fashion related departments belong, it was found that 35.5% belonged to design related division, and 22.6% belonged to Art and Physical Education Division. When analyzing the subjects of the colleges with Fashion Design Department (Major), the subject which took the biggest ratio was Clothing Construction and Pattern Drafting as 32.8% and the next was Design Area as 31.5%. In case of Fashion Stylist Department (Major), the subject area with the biggest share was Design Field (49.5%). If looking into segmented classification, design related subjects were 20.9%, and styling related subjects were 17.9%. In Fabric and Fashion related department, the subject with the biggest ratio was Dying and Textile Design as 40.4%, and Fabric related subjects were the next as 22.3%. In the Broadcasting Stylist related departments, the subjects of with the biggest ratio was Fashion Design related subjects as 37% and the next was Beauty related ones as 30.2%. According to the study result, it could be concluded that Fashion related departments in the colleges located in the Capital area focused on the subjects to nurture a fashion designer and their curricula are not specialized or differentiated but somewhat similar one another.

• The KSFM Journal of Fluid Machinery
• /
• v.10 no.2 s.41
• /
• pp.41-45
• /
• 2007

The shutoff unit was designed to provide rapid insertion of neutron absorbing material into the reactor core to shutdown the reactor quickly and also to withdraw the absorber slowly to avoid a log-rate trip. Four shutoff units were installed on the HANARO reactor but the half-core test facility was equipped with one shutoff unit. The reactor trip or shutdown is accomplished by four shutoff units by insertion of the shutoff rods. The shutoff rod(SOR) is actuated by a directly linked hydraulic cylinder on the reactor chimney, which is pressurized by a hydraulic pump. The rod is released to drop by gravity, when triplicate solenoid valves are de-energized to vent the cylinder. The hydraulic pump, pipe and air supply system are provided to be similar with the HANARO reactor. The shutoff rod drops for 647mm stroke within 1.13 seconds to shut down the reactor and it is slowly inserted to the full down position, 700mm, with a damping. We have conducted the drop test of the shutoff rod in order to show the performance and the structural integrity of operating system of the shutoff unit. The present paper deals with the 647mm drop time and the withdrawal time according to variation of the pool water temperature, the water level and the core flow.

• Journal of Periodontal and Implant Science
• /
• v.32 no.2
• /
• pp.325-338
• /
• 2002

Bone graft using growth factors and guided tissue regeneration have been used for the regeneration of infrabony defects which caused by periodontal disease. Calcium sulfate which is one of the resorbable barrier materials used for guided tissue regeneration. Platelet rich plasma which is a easy method to obtain the growth factors had many common points but, platelet rich plasma was still studying. This study was the comparative study between bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier material in clinical view. For the study, 28 sites(2 or 3 wall infrabony defects) were treated. 14 infrabony defects were received surgical implantation of BBP-calcium sulfate composite with a calcium sulfate barrier and the others received BBP mixed with platelet rich plasma. Clinical outcome was accessed 3 and 6 months of postsurgery. 1. There was no statistical difference between CS group and PRP group in pocket depth, gingival recession, clinical attachment level, and probing bone level at baseline. 2. There was statistically significant reduction in probing depth, clinical attachment level, and probing bone level at 3 and 6 months postsurgery(p<0.05). 3. In the probing depth and clincial attachment level PPR group had less improvement than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 4. In the recession PPR group had less recession than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 5. In the probing bone level PPR group had less improvement than CS group, but there was no statistically difference at 6 months postsurgery. In conclusion bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier showed similar clinical improvement for the treatment of 2 or 3 wall infrabony defects.