• KIEAE Journal
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• v.15 no.3
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• pp.15-20
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• 2015

Purpose: Suggesting a working prototype of a kinetic light shelf unit and revealing its energy efficiency by a series of building performance simulations were presented. Recently, kinetic building envelope has been an emerging technology as an innovative way to control exterior building environment, but products from many researches about the facade could not been reached to the industrialization so far. That is because its initial installation, operation and maintenance costs are still too high to use for the practical field, although buildings using kinetic envelopes could decrease their energy consumption significantly. This narrow point of view needs to be reconsidered, since buildings require great amount of energies to run their functions through the whole life and using better building components can lead to achieve much more benefits in aspects of the lifecycle cost (LCC). Method: A series of certified simulation tools like Ecotect and Green Building Studio that are normally used for researches and developments in the field of architecture were utilized. Result: Based on simulation analyses, the result of the study has showed that the proposed system definitely has adaptability to the professions and positively shows practicability as advanced integrative building envelopes with renewable energy association.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.83-90
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• 2009

As a series of 'Performance Assessment of Building Envelopes I: Double Skin Facade', three types (interior, exterior, mixed (int.&ext.)) of lightshelves and RetroLux were examined in terms of $CO_2$ emissions. It is shown that the exterior lightshelf could achieve the most energy savings (9.6-38.7%) in general office buildings due to blocking solar radiation before entering the indoor space. However, the interior lightshelf is the worst (1.4-5.2%) among three of them. The RetroLux has two components: (1) sun-reflector (first louver component), (2) light shelf for improving daylight induction (second louver component). Due to these two components, solar radiation from windows is filtered depending on seasonal variation (solar altitude). Therefore, the RetroLux can reduce 18.0-27.9% of annual energy consumption (both cooling and heating), and $552-3,290Won/m^2{\cdot}yr$ of operation cost is saved.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.846-856
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• 2017

The aim of this study was to develop the details of cross-laminated timber (CLT) envelops for satisfying the design standard for energy saving (DSEA) and passive standard in South Korea. When the same thickness of 180 mm concrete or CLT was used and the same materials for other layers were used for the roof, wall, and interlayer floor, the required insulation thickness for the different building envelopes in central, southern, and Jeju island was evaluated. As a result, compared to the concrete envelop, about 43 mm of insulation thickness was reduced for wall and roof with the CLT envelope. When the CLT envelopes were modified to protect the CLT from moisture based on FPInnovations (2011), the insulation thickness was further reduced by 12 mm. When the modified CLT building envelops satisfied with a passive standard are used for 10-story building, the required insulation was decreased by $40.89m^3$ for a floor ($105.27m^2{\times}2.3m$ in height) compared to concrete building. As the number of floors increases, about 3.58 m3 of insulation per floor was additionally saved.

• Korean Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.60-67
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• 1997

CAD systems offer a variety of techniques for designing and rendering models of static 3D objects and even of mechanisms, but relatively few tools exist for interactively specifying arbitrary movements of rigid bodies through space. Such tools are essential, not only for artistic animation, but also, for planning and demonstrating assembly and disassembly procedure of manufactured products. A rigid body motion is a continuous mapping from the time domain to a set of positions. To relieve the designers from the burden of specifying this mapping in abstract mathematical terms, combinations of simple rigid motion primitives, such as linear translations or constant axis rotations, are often used. These simple motions are planar and thus ill-suited for approximating arbitrary motions in 3D-space. Instead, we propose the screw motion primitive, a special combination of linear translations and constant axis rotations, which has a simple geometric representation that can be automatically and unambiguously computed from the starting and ending positions of the moving body. Although, any two positions may be interpolated by an infinity of motions, we chose the screw motion for its relative generality and its computational advantages. The paper covers original algorithms for computing the screw motions from interpolated positions and envelopes of swept regions to predict collisions.

• Structural Engineering and Mechanics
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• v.18 no.5
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• pp.627-644
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• 2004

In this study, the endochronic theory was used to investigate the collapse of thick-walled tubes subjected to external pressure and axial tension. The experimental and theoretical findings of Madhavan et al. (1993) for thick-walled tubes of 304 stainless steel subjected to external pressure and axial tension were compared with the endochronic simulation. Collapse envelopes for various diameter-to-thickness tubes under two different pressure-tension loadings were involved. It has been shown that the experimental results were aptly described by the endochronic approach demonstrated from comparison with the theoretical prediction employed by Madhavan et al. (1993). Furthermore, by using the rate-sensitivity function of the intrinsic time measure proposed by Pan and Chern (1997) in the endochronic theory, our theoretical analysis was extended to investigate the viscoplastic collapse of thick-walled tubes subjected to external pressure and axial tension. It was found that the pressure-tension collapse envelopes are strongly influenced by the strain-rate during axial tension. Due to the hardening of the metal tube of 304 stainless steel under a faster strain-rate during uniaxial tension, the size of the tension-collapse envelope increases.

• KIEAE Journal
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• v.17 no.1
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• pp.43-48
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• 2017

Purpose: Building owners or residents have concerns to strive for energy-saving and environmental conservation by utilizing with eco-friendlier energy resources for their physical environment. In this paper, an algae façade system is proposed as an energy-friendly building component to improve energy productivity and indoor environmental quality, and this study aims at verifying alternative technologies for implementing building elevations that contain various colors equipped with algae façade systems and suggesting design guidelines to enhance both building performance and design values. Method: The color of algae is basically ranged about the saturation green, and it is hardly converted to other variations. Such a problem can be resolved through the artificial lights like LED (Light Emitting Diode) lamps to mix the color from the algae and buildings could possibly change the elevation in many ways under the influence of daylight. Result: As a result, the suggested system may increase the aesthetic aspect of the building in response to environmental changes. The system cannot possibly be applied for only new construction, but also it can be utilized with the existing buildings as well. The proposed system is expected to be applied not only a new construction and any existing buildings as well, and it will cover from the environmentally friendly energy generation in the industry to a new application system for increasing energy efficiency and the beauty of building envelopes.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.56-60
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• 2010

The Cobitis hankugensis-Iksookimia longicorpa complex from Korea has been presumed to be a unisexual lineage, originating from C. hankugensis and I. longicorpa and having almost all females. Recently, it was confirmed that the complex consisted of one diploid and two triploid complexes. From observation of their oocyte envelopes, three forms could be classified: a villous projection in I. longicorpa, a granular one in C. hankugensis and two triploid complexes, and a granule with villous one in the diploid complex. Even within the same granular projection, they showed specific features in length and density number from each other. These architectures are first observed in cobitid complexes and may playa role in identification of diploids and triploids.

• Wind and Structures
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• v.31 no.5
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• pp.473-482
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• 2020

The first-order method for estimating the extreme wind pressure on building envelopes with consideration of the directionality of wind speed and wind pressure is improved to enhance its computational efficiency. In this improved method, the result is obtained directly from the empirical distribution of a random selection of annual maximum wind pressure samples generated by a Monte Carlo method, rather than from the previously utilized extreme wind pressure probability distribution. A discussion of the relationship between the first- and full-order methods indicates that when extreme wind pressures in a non-typhoon climate with a high return period are estimated with consideration of directionality, using the relatively simple first-order method instead of the computationally intensive full-order method is reasonable. The validation of this reasonableness is equivalent to validating two assumptions to improve its computational efficiency: 1) The result obtained by the full-order method is conservative when the extreme wind pressure events among different sectors are independent. 2) The result obtained by the first-order method for a high return period is not significantly affected when the extreme wind speeds among the different sectors are assumed to be independent. These two assumptions are validated by examples in different regions and theoretical derivation.

• Journal of Astronomy and Space Sciences
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• v.23 no.1
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• pp.11-18
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• 2006

We have modeled dust envelopes around silicate carbon stars using optical properties for a mixture of amorphous carbon and silicate dust grains paying close attention to the infrared observations of the stars. The 4 stars show various properties in chemistry and location of the dust shell. We expect that the objects that fit a simple detached silicate dust shell model could be in the transition phase of the stellar chemistry. For binary system objects, we find that a mixed dust chemistry model would be necessary.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.711-717
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• 2011

In this study, 5 types of PVS(Passive ventilation system) units are made and experimented its ventilation performance, thermal performance according to open rate and hole diameter of perforated aluminum plane. Results are as follows. 1) The ventilation performance increases approximately 50~70% according by the open rate of PVS increasing. Also, the ventilation performance increases about 2%~12% according by the hole diameter of PVS increasing. 2) In winter temperature/pressure condition(in : $20^{\circ}C$, out : $-2^{\circ}C/{\Delta}P$ : 0.2~5.0Pa) the temperature of inflow air decreases according by the open rate of PVS increasing. Heat gain performance decreases 10.1%, 25.6% when open rate increases 3) In the same condition, Heat gain performance decreases 18.3%, 18.8% according by the hole diameter of PVS increasing.