• Journal of the Korea Computer Graphics Society
• /
• v.7 no.3
• /
• pp.1-7
• /
• 2001

We present an efficient and robust algorithm to parametrize a perspective silhouette curve of a canal surface. We also detect each connected component of the silhouette. A canal surface is an envelope surface of a moving sphere with varying radii, which is defined by the center trajectory C(t) and radius function r(t) of the moving sphere. A canal surface can be decomposed to a set of characteristic circles. We derive the equations for the silhouette points on each characteristic circle, then parameterize the silhouette curve by using the equation. The sphere $S(t_*)$ with center point $C(t_*)$ and radius $r(t_*)$ intersects with the canal surface at a characteristic circle $K(t_*)$. The perspective silhouette of the sphere $S(t_*)$ from given view point consists of a circle $Q(t_*)$. By finding the values of t at which K(t) and Q(t) tangentially intersect, we detect each connected component of the silhouette curve.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.337-344
• /
• 2012

Today, the number of super tall buildings are under construction or being planed in Middle East and Asian Countries. For example the burj Khalifa, the tallest building in the world, is completed in 2008 and the height of that is about 800m. Also, Lotte World Tower is under construction in Korea. External environmental conditions such as wind speed, air temperature, humidity and solar radiation around the super tall building differs according to the building height due to the vertical micro climate change. However, the meteorological information used for AC design of building is obtained typically from standard surface meterological station data(~2m above the ground). In this paper the effect of the building envelope on heating and cooling load in super tall building considering the meteorological changes with height was analyzed with simulation method. As results of this research, the guideline to select the building envelop alternatives for super tall building will be suggested in this paper.

• Applied Microscopy
• /
• v.27 no.4
• /
• pp.417-432
• /
• 1997

The structures of the fertilized egg envelope in three species of cichlidae, golden severum (Cichlasoma severum var.), convic cichlid (Cichlasoma nigrofasciatum) and discus (Symphysodon aequifasciatus) were investigated by routine light and electron microscopies. The fertilized eggs of all three species were of the non-transparent, ellipsoidal, adhesive and non-floted type. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. In golden severum, an outer surface of egg envelope was covered by a reticular layer, that of convic cichlid was covered by an amorphous reticular layer and that of discus was covered by a branched reticular layer. The fertilized egg envelopes consisted of two distinct layers, an adhesive outer layer and an inner layer, consisted of lamellae alternating with interlamellae of lower electron density, in all three species; an inner layer of golden severum was $15\sim17$ layers, that of convic cichlid was $14\sim16$ layers, and that of discus was $18\sim19$ layers.

• Journal of the Korean Magnetics Society
• /
• v.4 no.2
• /
• pp.142-149
• /
• 1994

The Barkhausen noise was measured as the change of line width(39~1.22 mm) and scratching angle($90^{\circ}~50^{\circ}$) with respect of rolling direction in grain-oriented 3 % Si-Fe of 0.30 and 0.27 mm thickness. The two peak phenomena of the noise envelope observed for non-scratching and scratching of line width 39 mm was explained by large activation energy during $180^{\circ}$ domain wall nucleation and annihilation processes. The amplitudes of the noise envelpoes were decreased as the decrement of scratching line width, but did not almost changed below line width of 9.75 mm. It was explained that the decrease in the envelope with increasing scratching number is associated with lower activation energy of $180^{\circ}$ domain nucleation and annihilation in the vicinity of the scratching area. The noise power was decreased as narrower line width. The dependence of the power on the scratching angle was sharpest decreaded at the 50 angle.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.11a
• /
• pp.190-195
• /
• 2008

The objective of this research is to determine overall heat transfer coefficients (K-value) of exterior wall, floor, and roof of Nakseonjae, a Korean traditional residence via field measurement of transient heat flow and temperature difference across each envelope component. Heat flow sensors and T-type thermocouple were attached on the internal and the external surface of each building component, and real-time measurement data were collected for the three consecutive summer days. The K-values determined in this research showed good agreement with other results from open literature. Peak and annual thermal loads of the traditional residence estimated by a commercial energy simulation program were compared with those for a current apartment house. The traditional house showed lower annual cooling load than that of the current building. It may caused by the fact that the traditional building has less air-tight envelopes and no fenestration passing direct solar radiation into the space.

• Journal of The Korean Astronomical Society
• /
• v.26 no.2
• /
• pp.115-134
• /
• 1993

The light curve and radial velocity curve of multiperiodic dwarf cepheid VI719 Cyg (HD200925) with peculiar light curve have been reanalyzed in order to identify the oscillation modes to confirm the helium settling within the envelope. To do these, through the period search for the photometric and radial velocity data from the literature, two different periods were determined and the oscillation modes corresponding to the first and second periods were identified as the fundamental and first radial overtones. Hence the helium settling within the envelope was confirmed from the period ratio. The color excess, metallicity, effective temperature, and surface gravity corresponding to two different modes were determined and it was found that these parameters almost do not depend upon different oscillation mode. By utilizing the surface brightness method, we investigated the variation of angular diameter and radial displacement and it was found that the angular variation is very peculiar. Also by referring to the stellar models, mass and age were determined as $2.7M_{\bigodot}$ and 0.42 Gyr respectively which make this variable star heavier and younger than other multimode dwarf cepheids. Preliminary spectroscopic CCD observations were carried out and it was found that Mg in VI719 Cygni is nearly solar abundent according to the analysis of $5172.68{\AA}MgI$ line which is inconsistent with the photometric result. It was suggested that VI719 Cyg may be classified as a $\rho$ Pup stars according to the photometric characteristics.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.6
• /
• pp.105-112
• /
• 1999

In this paper we deal with tool interference problem in the case of compound surface machining. A new tool interference detection and correction method based on the envelope of the tool path is suggested to identify and correct the tool interference - not only within the local path of tool movement, but also outside of the tool path. Therefore, the developed strategy can be used to check the possible interference in any region of the surface. In order to analyze quantitatively the milled surface error produced by the tool interference, improved surface prediction model is also suggested in cutting process by general cutters. The effectiveness of the proposed method is demonstrated through simulation study.

• KIEAE Journal
• /
• v.5 no.1
• /
• pp.27-33
• /
• 2005

Global efforts have made to reduce energy consumption and $CO_2$ gas emission. One of the weakest parts for energy loss through the whole building components is building envelopes. Lots of technologies to increase the thermal performance of building envelopes have been introduced in recent year. Transparent Insulation Wall(TIW) is a new technology for building insulation and has been function both solar transmittance and thermal insulation. A mathematical model of a Transparent Insulation Wall equipped with south wall was proposed in order to predict thermal performance under varying climates(summer and winter). Unsteady state heat transfer equations were set up using an energy balance equation and solved using Gauss-Seidel iteration solution procedure. The thermal performance of the TIW determined from a wall surface and air layer temperature, non-airconditioned room temperature and air conditioning load. As a result, this numerical study shows that the TIW is effective in an air conditioning load reduction. Further experimental study is required to establish complete TIW system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.1
• /
• pp.21-27
• /
• 2000

We used the surface photovoltage spectroscopy(SPVS) for characterization of GaAs/Al\ulcornerGa\ulcornerAs multi-quantum well(MQW) structures grown by molecular beam epitaxy(MBE) method. Energy gap related transitions in GaAs and AlGaAs were observed. The Al composition(x=0.3) was determined by Sek's composition formula. Transition energies in MQW were determined using the differential surface photo-volatage spectroscopy)DSPVS) of the measured resonanced. In order to indentify the transitions, the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum well. We have observed and interesting behavior of the temperature dependence(80K~300K) of the 11Hand 11L transition for sample.

• Applied Microscopy
• /
• v.41 no.3
• /
• pp.189-196
• /
• 2011

Histological study on egg envelope and oogenesis of Kichulchoia multifasciata (Pisces, Cobitidae) was carried out by light microscopes and scanning electron microscopes. Various developmental cells appeared in ovary of the specimen catched during November 2010. The cytoplasm of oogonia was acidic and many nucleoli were located at the inner side of nucleus membrane. The size of the oogonia was $103.9{\pm}24.7$ ${\mu}m$ with nucleus size $42.9{\pm}6.9$ (31.1~50.3) ${\mu}m$. Primary oocyte having $277.5{\pm}60.5$ (216.7~354.9) ${\mu}m$ in diameter began to accumulate yolk vesicles. As the developmental stages proceed, secondary oocyte grows larger to $617.6{\pm}85.1$ (503.4~723.6) ${\mu}m$, and eosinophilic yolk granules yolk granules appeared between the yolk vesicles occupying most cytoplasm, and there are some yolk mass formed already. There are some yolk mass formed already. Envelope of fertilized egg investigated by a scanning electron microscope had plenty of microvilli (2~3 ${\mu}m$ in length) over the entire egg surface and a micropyle. Especially, the microvilli surrounding the micropyle were longer than those of egg surface with $5.26{\pm}1.22$ ${\mu}m$.