• Nuclear Engineering and Technology
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• v.38 no.7
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• pp.681-688
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• 2006

This study investigates the dynamic response characteristics of a structure impacted by a high speed projectile. The impact of a 300 kg projectile on a water storage tank is simulated by the general purpose computer codes ANSYS and LS-DYNA. Several methods to simulate the impact are considered and their results are compared. Based upon this, an alternative impact analysis method that is equivalent to an explicit dynamic analysis is proposed. The effect of fluid on the responses of the tank is also addressed.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.159-164
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• 2020

The response analysis of frame structure with open section beams considering warping conditions and short duration load have been performed. When a beam of frame structure is subjected under torsional moment, the cross section will deform a warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. Because of impact or blast loads, the wave propagation effects become increasingly important as load duration decreases. This paper presents that a warping restraint in finite element model effects the behavior of beam deformation, dynamic mode shape and response analysis. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame. A method to estimate the number of normal modes that are important is discussed.

• Journal of Korean Association for Spatial Structures
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• v.6 no.2 s.20
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• pp.131-136
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• 2006

It is important to evaluate energy absorption capacity of frames required during a design earthquake. An inelastic computer analysis based on mathematical modelling of energy absorbing frames and elements makes it possible to evaluate required energy absorption capacity. But such an analysis sometimes consumes much computation time particularly in case of complicated structural system. This paper presents a proposal to predict energy absorption of multi-bent steel frames by simple equivalent linear method.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1412-1414
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• 2009

It is suggested that the light extraction efficiency of the display device can be improved by adoption of periodic array of sub-wavelength scale structures. The relief of the total reflection has been investigated using the rigorous coupled wave analysis (RCWA). Various shape of the sub-wavelength scale structure allowed to have non vanishing transmittance for the light rays with the incident angle bigger than the critical angle.

• Korean Journal of Child Studies
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• v.26 no.4
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• pp.189-207
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• 2005

This study examined the effects of picture storybook making activities with computer plays on children's storytelling ability and creativity. Seventy 5-year-old children from two day-care classes participated in this eight-week program. The experimental class used the computer software of 'Stanley's Sticker Stories.' The comparison class used paper and pencil. Data analysis was implemented by ANCOVA and t-test. Significant differences were found between the experimental and comparison groups in story telling ability by story structure, imagination, vocabulary, sentence structure, and creativity showing that picture storybook making activities with the computer was more effective than traditional picture storybook making activities.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.230-244
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• 1996

We derive analytic expressions for the spontaneous emission spectrum (SES) of a multisection distributed feedback (DFB) structure device employing complex coupled gratings including the effects of both facets reflections. The multisection DFB structure device used in the analysis is a general model which allows the independent phase of a grating in each section, and the sections without gratings. The expressions are the same as those derived by makino and glinski in case the gratings are index coupled and the phase of a grating in each section, ${\varphi}_k$ is '0' which means the phase of gratings in the device is ocntinuous. The expressions for the SES of a phase-shift-controlled (PSC) DFB structure device using tunable devices are derived from the general expressions. The number of parametes of the expressions is reduced by using the parameter of effective phase shift defined by the sum of the phase shift in a PSC region and the difference of the phase of a grating in each active region. Equations showing the effect of both facets reflections and the effective phase shift on the SES are derived. The validaty of the equations is verified by computer simultions. Computer simulation results also show the possibility of evaluating the structure parametes of the device from its SES.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.311-316
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• 2001

The technology for characteristic analysis of device for high integration is changing rapidly. Therefore to understand characteristics of high-integrated device by computer simulation and fabricate the device having such characteristics became one of very important subjects. At devices become smaller from submicron to nanometer, we have investigated MOSFET built on an epitaxial layer(EPI) of a heavily-doped ground plane, and also newEPI MOSFET for improved structure to weak point of LDD structure by TCAD(Technology Computer Aided Design) to develop optimum device structure. We analyzed and compared the EPI device characteristics such as impart ionization, electric field and I-V curve with those of lightly-doped drain(LDD) MOSFET. Also, we presented that TCAD simulator is suitable for device simulation and the scaling theory is suitable at nano structure device.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.79-86
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• 2020

In this paper, we analyzed the case vulnerable to the power analysis attack of the ARIA algorithm and AES algorithm. Through this, we propose an algorithm with a safe structure for power analysis and prove through experiment. The proposed technique is a masking method using LFSR with a cyclic structure. To verify this, 1000, 2000, and 4000 power traces were collected, and the corresponding results are shown and proved. We used ATmega328 Chip for Arduino Uno for the experiment and mounted each algorithm. In order to measure the power consumption, a resistor was inserted and then proceeded. The analysis results show that the proposed structure has a safe structure for power analysis. In the future, we will study ways to lead to performance enhancement.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.101-106
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• 2005

When a underground structure is constructed at the site composed of soft soil, the behavior of a underground structure Is much affected by the motion of soft soil. Therefore, the effect of soil-structure interaction is an important consideration in the design of a underground structure such as tunnel at the site composed of soft soil. This paper presents the results of the study on dynamic response of tunnel structures and soil-structure interaction effects. The computer program SASSI was used in seismic analysis of tunnel structures because it is more capable of analyzing dynamic response or structures considering soil-structure interaction. As regards the results, the flexibility of surrounding soil affects dynamic response characteristics of tunnel structures and response of tunnel structures can be amplified.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.793-810
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• 2015

The TWINE is a new Generalized Feistel Structure (GFS) lightweight cryptosystem in the Internet of Things. It has 36 rounds and the key lengths support 80 bits and 128 bits, which are flexible to provide security for the RFID, smart cards and other highly-constrained devices. Due to the strong attacking ability, fast speed, simple implementation and other characteristics, the differential fault analysis has become an important method to evaluate the security of lightweight cryptosystems. On the basis of the 4-bit fault model and the differential analysis, we propose an effective differential fault attack on the TWINE cryptosystem. Mathematical analysis and simulating experiments show that the attack could recover its 80-bit and 128-bit secret keys by introducing 8 faulty ciphertexts and 18 faulty ciphertexts on average, respectively. The result in this study describes that the TWINE is vulnerable to differential fault analysis. It will be beneficial to the analysis of the same type of other iterated lightweight cryptosystems in the Internet of Things.