• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.3
• /
• pp.89-99
• /
• 1995

In this paper, we ecamined the effect that MCM-L technique influencess on the design and fabrication of multichip memory modules in increasing the packing desity of memory capacity and maximizing its electrical characteristics. For that purpose, we examined the effective methods of reducing the area of module layout and the wiring length with the variation of chip allocation and the number of wiring layers. We fabricated a 256K${\times}$8bit SRAM module with eight 32K${\times}$8bit SRAM chips. The routing experiment showed that we could optimize the area of module layout and wiring length by placing chips in a row, arranging module I/O pads parallel to chip I/O pads, and equalizing the number of terminal sides of module I/O's to that of chip I/O's. The routing was optimized when we used three wire layers in case of one sided chip mounting or five wire layers in case of double sided chip mounting. The fabricated modules showed 18.9 cm/cm$^{2}$ in wiring density, 65 % in substrate occupancy efficiency, and module substrate and functionally tested to find out the module working perfectly.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.04a
• /
• pp.180-184
• /
• 2008

Fire prevention strategies should be aimed at the prevention of structured fire since average annual rates of structured fire have been increased due to economic growth resulted in increasing high rise buildings and multipurpose occupancies over the past ten years. Hence, this study mainly focused on the improve method and problems in the field test of fire detector in compliances with experimental consideration. And it leads us to the flowing conclusions : Firstly, it is necessary to formulate a safety standards on field test. Nowadays, the test enforced in many ways without formulated standard. Therefore it is necessary to be complete the arrangements standardized and how to do the test with formulated safety standards. Second, it is necessary to establish the regal guidance with regard to inspection equipment, ie density, component and temperature of test equipment should be considered. Also the equipment is need to be standardized and improved. Third, fire inspector's competency in their practice should be enhanced. The problems arising from the lack of knowledge and competence regarding inspection could be settled by providing professional education to ensure proficiency in their practice. Specialized training, as has been noted, should be offered in accordance with occupancy type, scale and fire protection system in the fire facilities.

• Journal of the Korean Solar Energy Society
• /
• v.22 no.4
• /
• pp.85-96
• /
• 2002

Recently the number of auditoriums such as theaters, assembly halls, and concert halls is increasing in Korea. Auditoriums have generally large space volume, have a high density of occupancy per unit floor area, compared to other buildings. Since they have relatively high ceilings, some heat may stratify above the occupied zone. The under floor air conditioning system, which is set under seats, is frequently selected in an auditorium, because typical air conditioning system where air is supplied from ceilings often causes drafts and unequal temperature distribution. Therefore, this study aims to suggest basic data for air conditioning system design of a middle-sized auditorium. Features and problems of air conditioning system of an auditorium which has about 500 seats are investigated as a case study. In addition, indoor thermal comfort and cooling energy consumption are analyzed with a CFD program and an energy analysis program.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.49 no.5
• /
• pp.287-291
• /
• 2023

Odontogenic keratocysts (OKCs) located in the maxillae have rarely been reported in the literature. Standard treatment modalities for OKC range from marsupialization to marginal resection. However, most of the studies on OKC treatment have been related to mandibular OKCs. The anatomical structure and loose bone density of the maxillae and the empty space of the maxillary sinus could allow rapid growth of a lesion and the ability to tolerate tumor occupancy in the entire maxilla within a short period of time. Therefore, OKCs of the maxillae require more aggressive surgery, suchas resection. As an alternative, this report introduces a modified Carnoy's solution, a strong acid, as an adjuvant chemotherapy after cyst enucleation. This report describes the clinical outcomes of enucleation using a modified Carnoy's solution in patients with large OKCs on the posterior maxillae. In three cases, application of a modified Carnoy's solution had few side effects or morbidity. Each patient was followed for four to six years, and none showed any signs of recurrence. In conclusion, adjuvant treatment with a modified Carnoy's solution can be considered a treatment option capable of reducing the recurrence rate of OKC in the maxillae.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.7
• /
• pp.691-696
• /
• 2004

The electronic state and chemical bonding of $\beta$-MnO$_2$ with transition metal dopants were theoretically investigated by DV-X$_{\alpha}$ (the discrete variational X$_{\alpha}$) method, which is a sort of the first principles molecular orbital method using the Hartree-Fock-Slater approximation. The calculations were performed with a $_Mn_{14}$ MO$_{56}$ )$^{-52}$ (M = transition metals) cluster model. The electron energy level, the density of states (DOS), the overlap population, the charge density distribution, and the net charges, were calculated. The energy level diagram of MnO$_2$ shows the different band structure and electron occupancy between the up spin states and down spin states. The dopant levels decrease between the conduction band and the valence band with the increase of the atomic number of dopants. The covalency of chemical bonding was shown to increase and ionicity decreased in increasing the atomic number of dopants. Calculated results were discussed on the basis of the interaction between transition metal 3d and oxygen 2p orbital. In conclusion it is expected that when the transition metals are added to MnO$_2$ the band gap decreases and the electronic conductivity increases with the increase of the atomic number of dopants. the atomic number of dopants.

• Journal of Broadcast Engineering
• /
• v.26 no.6
• /
• pp.692-703
• /
• 2021

Recently, with the development of computer graphics technology, research on technology for expressing real objects as more realistic virtual graphics is being actively conducted. Point cloud is a technology that uses numerous points, including 2D spatial coordinates and color information, to represent 3D objects, and they require huge data storage and high-performance computing devices to provide various services. Video-based Point Cloud Compression (V-PCC) technology is currently being studied by the international standard organization MPEG, which is a projection based method that projects point cloud into 2D plane, and then compresses them using 2D video codecs. V-PCC technology compresses point cloud objects using 2D images such as Occupancy map, Geometry image, Attribute image, and other auxiliary information that includes the relationship between 2D plane and 3D space. When increasing the density of point cloud or expanding an object, 3D calculation is generally used, but there are limitations in that the calculation method is complicated, requires a lot of time, and it is difficult to determine the correct location of a new point. This paper proposes a method to generate additional points at more accurate locations with less computation by applying 2D interpolation to the image on which the point cloud is projected, in the V-PCC technology.

• Journal of Korean Society of Transportation
• /
• v.20 no.1
• /
• pp.91-99
• /
• 2002

The purpose of in this paper is to estimate the capacity and to suggest the level of service for pedestrian walkway. To estimate the pedestrian walkway capacity, Pedestrian density and speed were collected at the walkways in the subway station and the sidewalks. The simple linear repression of pedestrian density and speed models were developed for the relationships between the pedestrian flow rate and the pedestrian speed. The analysis results are as follow : First. the ranges of capacity for walkway were found minimum 106p/m/m and maximum 126p/m/m. The capacity of walkway was suggested to 106p/m/m for 2001 KHCM. Second, it found that the range of the critical speeds were between 40m/minute and 43m/minute and the range of the critical densities were between 2.65 p/$m^2$ and 2.85 p/$m^2$. Third, the range of level of service are similar to that of the 2,000 US HCM. This study suggests that occupancy, density and speed at Los E use 0.38$m^2$/p, 2.6 p/$m^2$ and 40m/minute respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.1
• /
• pp.67-74
• /
• 2002

A phosphor for Plasma Display Panel, BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$, showing a blue emission band at about 450nm was prepared by a solid-state reaction using BaCO$_3$, $Al_2$O$_3$, MgO, Eu$_2$O$_3$ as starting materials wish flux AlF$_3$. The study of the behaviour of Eu in BAM phosphor was carried out by the photoluminescence spectra and the Rietveld method with X-ray and neutron powder diffraction data to refine the structural parameters such as lattice constants, the valence state of Eu, the preferential site of Mg atom and the site fraction of each atom. The phenomenon of the concentration quenching was abound 2.25~2.3wt% of Eu due to a decrease in the critical distance for energy transfer of inter-atomic Eu. Through the combined Rietveld refinement, R-factor, R$_{wp}$, was 8.11%, and the occupancy of Eu and Mg was 0.0882 and 0.526 at critical concentration. The critical distance of Eu$^{2+}$ in BAM was 18.8$\AA$ at 2.25% Eu of the concentration quenching. Furthermore, c/a ratio was decreased to 3.0wt% and no more change was observed over that concentration. The maximum entropy electron density was found that the modeling of $\beta$-alumina structure in BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$correct coincided showing Ba, Eu, O atoms of z= 1/4 mirror plane.e.ane.e.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.3
• /
• pp.197-203
• /
• 1993

Greenhouse experiments were conducted to avaluate strain competition, nodulation, patterns of nodule occupancy and population changes of Bradyrhizobium sp. strain HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$ in the rhizosphere of peanut(Arachis hypogaea L.) under different root temperatures. Inoculated with two strains using seed coating with peat slurry under different root temperatures, population of each strain in the rhizosphere increased with plant growth and multiplication rate of inoculum in the unit weight of root were showed the highest from 10 to 15days after sowing. The multiplication rate of inoculum in the rhizosphere was $28^{\circ}C$>$34^{\circ}C$>$22^{\circ}C$. The density of HCR-46 $str^{r}cep^{r}$ was more increased than that of CB756 $str^{r}rif^{r}$ under $22^{\circ}C$ and $28^{\circ}C$. While the density of two strains showed no difference under $34^{\circ}C$. Inoculated with HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$, respectively at 22, 28 and $34^{\circ}C$, nodulation of each strain was dominated in its inoculation portion. Inoculated with the mixture of HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$, occupancy rate of HCR-46 $str^{r}cep^{r}$ was dominated over that of CB756 $str^{r}rif^{r}$ at $22^{\circ}C$ and $28^{\circ}C$, but that was similar between them at $34^{\circ}C$. Dry mass, nodulation, nitrogen content per plant and nitrogenase activity showed higher at $28^{\circ}C$ than at $32^{\circ}C$ and $22^{\circ}C$, while those were higher in HCR-46 $str^{r}cep^{r}$ and mixing HCR-46 $str^{r}cep^{r}$ with CB756 $str^{r}rif^{r}$ than in CB756 $str^{r}rif^{r}$.

• Korean Journal of Environment and Ecology
• /
• v.34 no.1
• /
• pp.18-26
• /
• 2020

Echinosophora koreensis (Nakai) Nakai an endemic plant with limited distribution in some parts of the Korean Peninsula, is designated as "Endangered" species on the IUCN Red List. The species is under the threat of deterioration in nature due to various environmental changes causing loss of natural habitats. We investigated the distribution pattern and population structure of E. koreensis to serve as a basic reference for identifying the dynamics and persistence of natural populations of this species in the future. To determine the characteristics of the E. koreensis population, we laid two to three large plots sized 20m×30m on the ridgeline as the reference in Yanggu, Chuncheon, and Hongcheon and laid four to seven small quadrats sized 1m×1m on the transect. A total of 530 plots were laid, 10 each at 2m interval, to measure the number of the stems, the number of fruiting, height, and other factors. The collected distribution information was compared with the existing IUCN assessed categories by applying IUCN Red List ver 3.1 Criteria B. The average population density of the three surveyed areas was 3.47 stem/㎡; the density of each area was 3.95 stems/㎡ in Yanggu, 3.37 stems/㎡ in Chuncheon, and 2.87 stems/㎡ in Hongcheon. The number of fruiting per stem was 0.0038, indicating only 7 fruits out of 1,837 stems and that vegetative reproduction is likely to be more dominant than sexual reproduction. The distribution tendency of population density in the small plots in three surveyed areas showed that the density of E. koreensis tended to decrease toward the center of the forest with low crown openness and around the mountain ridge with high crown openness. It indicated that the quantity of light could be a very important factor for the growth of individuals of this species. The analysis of the heights of individuals present in the surveyed plots showed a range of 2.3 ~ 68.5cm and an average of 20.1cm. An analysis on the stage-structure of the E. koreensis population based on the sieve height found that the appearance frequency decreased with increasing height above 15 ~ 20cm and that the percentage of individuals lower than 10cm, which were presumed to be seedlings, was severely low, indicating a necessity of study on the population sustainability based on the monitored data. The occupied area calculated with the collected species distribution information was 200㎢, indicating the EN category according to the IUCN Red List Reference B.