• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.629-639
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• 1998

This paper summarizes the results of full-scale cyclic seismic performance tests on three column-tree type steel moment connections. Each test specimen consisted of a $H-600{\times}200$ beam and a $H-400{\times}400$ column of SS41 (SS400). Key parameter included was column PZ (panel zone) strength relative to beam strength. The seismic performance of specimen with stronger PZ tended to be inferior. Total plastic rotations available in the specimens ranged from 1.8 to 3.0 (% rad). The limited test results in this study seem to support the speculation that permitting PZ yielding shall be more beneficial to enhancing total plastic rotation capacity of the moment connection. Beam flange fracture across the heat affected zone and divot-type pullout of the column flange were observed in the tests. A conceptual mechanical model consistent with observed test results was also sought.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.450-460
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• 2005

Today, multimedia information is used on the internet and various social areas by rapid development of computer and communication technology. Therefor, the usage is growing dramatically. Multimedia information analysis system is basically based on text. So, there are many difficult problems like expressing ambiguity of multimedia information, excessive burden of works in appending notes and a lack of objectivity. In this study, we suggest a method which uses color and shape information of multimedia image partitions efficiently analyze a large amount of multimedia information. Partitions use field growth and union method. To extract color information, we use distinctive information which matches with a representative color from converting process from RGB(Red Green Blue) to HSI(Hue Saturation Intensity). Also, we use IMI(Improved Moment Invariants) which target to only outline pixels of an object and execute computing as shape information.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1091-1097
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• 2011

This study aims to develop the plastic suspension assembly which is installed on inside of vehicle seat and supports passenger's back to provide the comfortable feeling. This design is the suspension structure to support the back equally and assemble seat back frame and plastic suspension effectively. The parts of suspension are designed by considering the property of body pressure distribution. As analysis values are approached to measured values by comparing the deformations in the cases of existed spring suspension and developed plastic suspension, the optimum design can be established.

• 대한공업교육학회지
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• v.34 no.2
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• pp.363-378
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• 2009

The objective of the paper is to design and produce a walking robot such as humanoid robot under the given design requirements and constraints. An approach to design and produce walking robot with 2 legs was suggested. It is walking robot of 5 joints which have both of ankles, both of knee joint, and pelvis. It has 5 degrees of freedom and moves by only rotations. We review the key points before the design of the walking robot. The walking robot is consisted of 2 portions : motor and frame, control board. Final goal is to walk stably and if it detects and cognizes a special object, the walking robot avoids it and moves in other direction. The walking robot was made according to design procedures and tested by proposed algorithms. The running test was successful under given 4 modes. The findings of this research could think kinds of technologies concurrently and approach synthetically through process of design and production.

• Journal of KIISE
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• v.44 no.4
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• pp.344-351
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• 2017

An attribute based signature system is a cryptographic system where users produce signatures based on some predicate of attributes, using keys issued by one or more attribute authorities. If a private key is leaked during signature generation, the signature can be forged. Therefore, signing operation computations should be performed using secure hardware, which is called tamper resistant hardware in this paper. However, since tamper resistant hardware does not provide high performance, it cannot perform many operations requiring attribute based signatures in a short time frame. This paper proposes a new attribute based signature system using high performance general hardware and low performance tamper resistant hardware. The proposed signature scheme consists of two signature schemes within a existing attribute based signature scheme and a digital signature scheme. In the proposed scheme, although the attribute based signature is performed in insecure environments, the digital signature scheme using tamper resistant hardware guarantees the security of the signature scheme. The proposed scheme improves the performance by 11 times compared to the traditional attribute based signature scheme on a system using only tamper resistant hardware.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.176-184
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• 2005

In this paper, we implemented an Elliptic Curve Cryptography(ECC) processor for Digital Transmission Contents Protection (DTCP), which is a standard for protecting various digital contents in the network. Unlikely to other applications, DTCP uses ECC algorithm which is defined over GF(p), where p is a 160-bit prime integer. The core arithmetic operation of ECC is a scalar multiplication, and it involves large amount of very long integer modular multiplications and additions. In this paper, the modular multiplier was designed using the well-known Montgomery algorithm which was implemented with CSA(Carry-save Adder) and 4-level CLA(Carry-lookahead Adder). Our new ECC processor has been synthesized using Samsung 0.18 m CMOS standard cell library, and the maximum operation frequency was estimated 98 MHz, with the size about 65,000 gates. The resulting performance was 29.6 kbps, that is, it took 5.4 msec to process a 160-bit data frame. We assure that this performance is enough to be used for digital signature, encryption and decryption, and key exchanges in real time environments.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.275-287
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• 2000

A virtual reality system must provide participants with a natural interaction, a sufficient immersion, and mostly, realistic images. To achieve this, it is crucial to provide a fast and uniform rendering speed regardless of the complexity of virtual worlds, or the complexity of simulation. In this paper, a virtual reality system which offers an improved rendering performance for complex virtual reality applications has been designed and implemented. The key idea of the proposed system is to exploit the multi-thread scheme in system module design, and execute each modules in parallel. Taking such design approach, rendering, simulation, and interaction can be executed independently. Hence, in applications where a simulation is complex or a scene is very large, this system can provide a more uniform and faster frame rates. The proposed method has been experimented under the various application environments in which scenes and simulations are very complex.

• Journal of Korean Society of Steel Construction
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• v.18 no.4
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• pp.481-490
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• 2006

The actual performance of a building during an earthquake depends on many factors. The prediction of the seismic performance of a new or existing structure is complex, due not only to the large number of factors that need to be considered and the complexity of the seismic response, but also due to the large inherent uncertainties and randomness associated with making these predictions. A central issue of this research is the proper treatment and incorporation of these uncertainties and randomness in the evaluation of structural capacity and response has been adopted in the seismic performance evaluation of steel tall buildings to account for the uncertainties and randomness in seismic demand and capacities in a consistent manner. The basic framework for reliability-based seismic performance evaluation and the key factors for statistical studies were summarized. A total of 36 target structures that represent typical tall steel buildings based on national building code (KBC-2005) were designed for the statistical studies of demand factor s and capacity factors. The incremental dynamic analysis (IDA) approach was examined through the simple steel moment frame building in determination of global drift capacity.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.360-366
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• 2017

In commercial vehicles such as frame-based mid-size trucks, it is easy to reduce vibration caused by driveline with the cab mount system. There are no critical driveline vibration problems associated with these vehicles up to now. However, in the case of a similar grade of monocoque type mini-bus, there are no effective vibration isolation components such as a cab mount. Vibration caused by driveline is quite a complex problem to understand in terms of which part governs the phenomenon and how the problem can be solved. Thus, we have to manage the design factor about the driveline and mount system strictly at the early stage of vehicle development. Low frequency vibration caused by the driveline system is investigated in this study. We created the CAE driveline model and analyze low frequency vibration. Then contribution analysis about each design factor of driveline and mount system is performed. Finally, we can obtain the optimized design factor for a driveline system of a mini-bus, which is verified by the vehicle test results.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.268-277
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• 2003

In this paper, we propose a new video watermarking method exploiting the human visual system (HVS) to find effective locations. in the video frames which make the watermark robust and imperceptible simultaneously. In particular, we propose a new HVS-optimized weighting map for hiding the watermark by considering HVS in three different aspects : frequency, spatial, and motion masking effects. The global masking map is modeled by combining the frequency masking, the spatial masking, and the motion masking. In this paper, we use a watermark which is generated by the bitwise exclusive-OR operation between a logo image and a random sequence. The amount of watermarks is weighted by a control parameter. Furthermore, we embed the watermark in the uncompressed video sequence for the general watermarking method available to various coding schemes. Simulation results show that the watermark is imperceptible and the proposed method is good for watermark capacity. It is also demonstrated that the proposed method is robust against various attacks, such as MPEG coding, MPEG re-encoding, and frame attacks.