• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.1
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• pp.31-42
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• 2019

In this study, the results of an analytical investigation on the seismic behavior of two residential 4-story bearing wall buildings with pilotis, each of which has symmetric or unsymmetric wall arrangement at their piloti level, are presented. The dynamic characteristics and lateral resistance of the piloti buildings were investigated through linear elastic and nonlinear static analyses. According to the results, the analytical natural period of vibration of the piloti buildings were significantly shorter than the fundamental period calculated in accordance with KBC 2016. In the initial elastic behavior, the walls resisting in-plane shear contributed to the lateral stiffness and strength, while the contribution of columns resisting flexural moments in double curvature was limited. However, after the shear cracking and yielding of the walls occurred, the columns significantly contributed to the residual strength and ductility. Based on those investigations, design recommendations of low-rise bearing wall buildings with piloti configuration are given.

• Steel and Composite Structures
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• v.29 no.5
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• pp.669-680
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• 2018

The rapidly decreasing natural resources and the global variation of the climate push us to find intelligent and efficient structural systems to provide more people with fewer resources. This paper proposed a kinematic cable-strut system to realize sustainable structures in responding to changing environmental conditions. At first, the concept of the kinematic system based on crystal-cell pyramid (CP) cable-strut unit was given. Then the deployment of the structure was studied experimentally. After that, the static behaviors in the fully deployed state under the symmetric and asymmetric load cases were investigated. Moreover, the effects of thermal loading and the initial prestress distribution were also discussed. Comparative studies between the proposed structure and other deployable cable-strut system under three times of design load cases were carried out. Finally, the robustness of the system was studied by removal of one passive cable at one time.

• Earthquakes and Structures
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• v.26 no.5
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• pp.337-348
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• 2024

This paper presents a new seismic isolation design for liquid storage tank (LST). The seismic isolation system includes: LST, flexible membrane, sand mat and rolling seismic isolation devices. Based on the mechanical equilibrium theory, the symmetric concave rolling restoring force model of the isolation device is derived. Based on the elasticity theory and restoring force model of the seismic isolation, a simplified mechanical model of LST with the new seismic isolation is established. The rationality of the seismic isolation design of LST is explored. Meanwhile, the seismic response of the new seismic isolation LST is investigated by numerical simulation. The results show that the new seismic isolation tank can effectively reduce the seismic response, especially the control of base shear and overturning moment, which greatly reduces the risk of seismic damage. The seismic reduction rate of the new seismic isolation storage tanks in Class I, II, and III sites is better than that in Class IV sites. Moreover, the seismic isolation device can effectively control the ground vibration response of storage tanks with different liquid heights. The new seismic isolation LST design provides better isolation for slender LSTs than for broad LSTs.

• Korean Institute of Interior Design Journal
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• v.26 no.2
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• pp.101-109
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• 2017

The food and beverage spaces of modern industrial society have transformed from a simple space for meals into a space of culture, communication and experience as society becomes more complex and diverse along side economic growth. An interior designer who is rapidly rising on this flow of change is Yukio Hashimoto. While working for interior design firm Super Potato, which highlights food and beverage spaces, he was much affected by the expression methods of representative designer Takashi Sugimoto, who makes use of natural elements. By using these expression methods that make use of natural elements in his own creation of spatial ambience and elements of experience and by adding his own differentiated expression methods, he emphasizes an effective spatial expression for food and beverage spaces. The design characteristics of Yukio Hashimoto's food and beverage spaces are as follows. First natural elements like light and water are recreated as memories of nature after being established through a methodology that allows these elements to penetrate his own thoughts. Second, he pursues a hybrid design through the harmony between past tradition and current expressive techniques. Third, he expresses objets of light through a formative sense of shape expressed with light.. Fourth, he establishes an axis in the interior space by light and structure and endows a strong directionality that induces symmetric characteristics, gaze, and movement.. Fifth, he installs lights at the bottom of weighty materials and expresses a sense of floating by light. Sixth, he uses an illusion technique that makes use of the ambiguity and depth of space resulting from reflecting materials like mirrors. The study hopes that such design expression characteristics of food and beverage spaces can be used as data for interior designers to apply and develop a new design vocabulary.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.778-784
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• 2012

A symmetric block cryptosystem uses an identical cryptographic key at encryption and decryption processes. HIGHT cipher algorithm is 64-bit block cryptographic technology for mobile device that was authorized as international standard by ISO/IEC on 2010. In this paper, block cipher HIGHT algorithm is designed using Verilog-HDL. Four modes of operation for block cipher such as ECB, CBC, OFB and CTR are supported. When continuous message blocks of fixed size are encrypted or decrypted, the desigend HIGHT core can process a 64-bit message block in every 34-clock cycle. The cryptographic processor designed in this paper operates at 144MHz on vertex chip of Xilinx, Inc. and the maximum throughput is 271Mbps. The designed cryptographic processor is applicable to security module of the areas such as PDA, smart card, internet banking and satellite broadcasting.

• Journal of computational fluids engineering
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• v.17 no.4
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• pp.49-55
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• 2012

Research has importance in proposing the design of a tunnel with a vertical vent to secure passengers in a comfortable environment and safe against pressure. Using several analysis methods, the magnitude of the pressure induced by the vertical vent in the tunnel can be analyzed. In addition to the 3-dimensional method, the 2-dimensional method and the 2-dimensional axis-symmetric method are also used to analyze the strong and weak points of each so that the optimum analysis method can be obtained. As a result, it appears that the 2-dimensional axis-symmetric method is the most suitable in analyzing tunnel pressure consider to accuracy and time effective aspect. Also, the 3-dimensional method is disadvantageous in that it takes longer in calculating results, but is more effective in predicting phenomena around the vertical vent in the tunnel.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.327-335
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• 2011

This study has two objectives: (1) to evaluate the degradation characteristics of symmetric unbraced steel frames by using analytical approach, and (2) to suggest equation which can approximately estimate the effect of degradation during the schematic design stage. For the analytical approach, the refined plastic hinge method with an arc length algorithm was adopted. The subject of analysis was one story one-bay, multistory one-bay, and multistory three-bay unbraced steel frames. The main parameters of the analytical approach include the stiffness ratio of column to beam and the axial force ratio. The study led to the following conclusions. The normalized stiffness of degradations is affected by both stiffness ratio of column to beam and the axial load ratio; however, the major influence on degradations is the axial force ratio. The equation, which can approximately estimate the effect of degradation, was suggested together with the research results.

• Convergence Security Journal
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• v.19 no.5
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• pp.47-53
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• 2019

Network-based sharing of information has evolved into a cloud service environment today, increasing its number of users rapidly, but has become a major target for network-based illegal attackers.. In addition, IP spoofing among attackers' various attack techniques generally involves resource exhaustion attacks. Therefore, fast detection and response techniques are required. The existing detection method for IP spoofing attack performs the final authentication process according to the analysis and matching of traceback information of the client who attempted the connection request. However, the simple comparison method of traceback information may require excessive OTP due to frequent false positives in an environment requiring service transparency. In this paper, symmetric key cryptography based on traceback information is used as mutual authentication information to improve this problem. That is, after generating a traceback-based encryption key, mutual authentication is possible by performing a normal decryption process. In addition, this process could improve the overhead caused by false positives.

• Wind and Structures
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• v.29 no.6
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• pp.457-469
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• 2019

In this paper, a numerical solution is presented for supersonic flutter analysis of cantilever non-symmetric functionally graded (FG) sandwich plates. The plate is considered to be composed of two different functionally graded face sheets and an isotropic homogeneous core made of ceramic. Based on the first order shear deformation theory (FSDT) and linear piston theory, the set of governing equations and boundary conditions are derived. Dimensionless form of the governing equations and boundary conditions are derived and solved numerically using generalized differential quadrature method (GDQM) and critical velocity and flutter frequencies are calculated. For various values of the yaw angle, effect of different parameters like aspect ratio, thickness of the plate, power law indices and thickness of the core on the flutter boundaries are investigated. Numerical examples show that wings and tail fins with larger length and shorter width are more stable in supersonic flights. It is concluded for FG sandwich plates made of Al-Al₂O₃ that increase in volume fraction of ceramic (Al₂O₃) increases aeroelastic stability of the plate. Presented study confirms that improvement of aeroelastic behavior and weight of wings and tail fins of aircrafts are not consistent items. It is shown that value of the critical yaw angle depends on aspect ratio of the plate and other parameters including thickness and variation of properties have no considerable effect on it. Results of this paper can be used in design and analysis of wing and tail fin of supersonic airplanes.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1158-1168
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• 2005

A shunt from the left ventricle to the left anterior descending artery is being developed for coronary artery occlusive disease, in which the shunt or conduit connects the the left ventricle (LV) with the diseased artery directly at a point distal to the obstruction. To aid in assessing and optimizing its benefit, a computational model of the cardiovascular system was developed and used to explore various design conditions. Computational fluid dynamic analysis for the shunt hemodynamics was also done using a commercial finite element package. Simulation results indicate that in complete left anterior descending artery (LAD) occlusion, flow can be returned to approximately 65% of normal, if the conduit resistance is equal for forward and reverse flow. The net coronary flow can increase to 80% when the backflow resistance is infinite. The increases in flow rate produced by asymmetric flow resistance are enhanced considerably for a partial LAD obstruction, since the primary effect of resistance asymmetry is to prevent leakage back into the ventricle during diastole. Increased arterial compliance has little effect on net flow with a symmetric shunt, but considerably augments it when the resistance is asymmetric. The computational results suggest that an LV-LAD conduit will be beneficial when the resistance due to artery stenosis exceeds 27 PRU, if the resistance is symmetric. Fluid dynamic simulations for the shunt flow show that a recirculating region generated near the junction of the coronary artery with the bypass shunt. The secondary flow is induced at the cutting plane perpendicular to the axis direction and it is in the attenuated of coronary artery.