• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.71-78
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was peformed. The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used. The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• Steel and Composite Structures
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• v.7 no.5
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• pp.391-404
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• 2007

This paper presents push-out tests of stud shear connectors to examine their fatigue behavior for developing a new composite bridge deck system. The fifteen push-out specimens of D16 mm stud welded on 9 mm steel plate were fabricated according to Eurocode-4, and a series of fatigue endurance test and residual strength test were performed. Additionally, the stiffness and strength variations by cyclic loading were compared. The push-out test, when the stiffness reduction ratio of the specimens was 0.95 under cyclic load, resulted in the failure of the studs. The stiffness variation of the push-out specimens additionally showed that the application of cyclic loads reduced the residual strength. The fatigue strength of the shear connectors were compared with the design values specified in the Eurocode-4, ASSHTO LRFD and JSSC codes. The comparison result showed that the fatigue endurance of the specimens satisfies the design values of these codes.

• ETRI Journal
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• v.26 no.1
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• pp.13-20
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• 2004

We propose a new optical code division multiple access (OCDMA) scheme for reducing multiple access interference (MAI) and enhancing performance for optical subscriber access networks using modified pseudorandom noise (PN)-coded fiber Bragg gratings with bipolar OCDMA decoders. Through the bipolar OCDMA decoder and the modified PN codes, MAI among users is effectively depressed. As the data are encoded either by a unipolar signature sequence of the modified PN code or its complement according to whether the data bit is 1 or 0, the bit error ratio (BER) can be more improved with the same signal to interference plus noise ratio over the conventional on-off shift keying-based OCDMA system. We prove by numerical analysis that the BER of the proposed bipolar OCDMA system is better than the conventional unipolar OCDMA system. We also analyze the spectral power distortion effects of the broadband light source.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1019-1025
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• 2006

There are so many related policies to design and construct building mechanical system. Therefore, preferentially in this study, purposes and major contents of related laws are summarized briefly. Subsequently, some points at issue and ways to improve laws and codes for energy conservation are suggested. From the results of this study, some points at issue are as follows : (1) Inconvenience in the application due to dispersion of similar codes. (2) Lack of systems and tools to verify and to evaluate the effect of energy conservation by any policy (3) Lack of the incentive Policy for Participator to conserve of energy.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.55-66
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• 2019

Storage system often applies erasure codes to protect against disk failure and ensure system reliability and availability. Liberation code that is a type of coding scheme has been widely used in many storage systems because its encoding and modifying operations are efficient. However, it cannot effectively achieve fast recovery from single disk failure in storage systems, and has great influence on recovery performance as well as response time of client requests. To solve this problem, in this paper, we present HRSF, a Hybrid Recovery method for solving Single disk Failure. We present the optimal algorithm to accelerate failure recovery process. Theoretical analysis proves that our scheme consumes approximately 25% less amount of data read than the conventional method. In the evaluation, we perform extensive experiments by setting different number of disks and chunk sizes. The results show that HRSF outperforms conventional method in terms of the amount of data read and failure recovery time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.485-488
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• 2009

The class of BCH codes is a large class of error correction codes. HDL implementation of BCH code generator to change code rate. and used System Generator, and implemented hardware to FPGA. Loaded bit stream to a FPGA board in order to verify this design to Hardware co-simulation from these results. Also, compared as investigated the maximum action frequency through timing analysis and resource of logic in order to evaluate performance of BCH code generator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.879-888
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• 2000

In this paper, the performance of IS-95B CDMA system adopting multi-code scheme for data service on the forward link is obtained by theoretical analysis and computer simulation. The wireless channel is assumed to include AWGN, MUI(Multi-User Interference), and MPI(Multi-Path Interference), and multipath Rayleigh fading modeled by TDL(Tapped Delay Line). To obtain actual performance, IS-95B system using PN codes(M-sequence) concatenated with Walsh codes is considered. The BER performance of voice/data service satisfying QoS requirement and the maximum capacity of voice users is derived in terms of various system parameters(voice activity factor, required SNR of voice/data users, the number of multi-codes, the number of voice/data users.,etc.). As a result, under the condition that the maximum allowable number of voice user is 38 in voice only system, as the number of multi-code is decreased by 1, the maximum allowable number of voice user is increased by 5% for system with 1 data user and 22.3% for system with 4 data users. Therefore, it is possible to increase maximum allowable number of users in IS-95B CDMA system by appropriate control of the number of multi-codes and required SNR according to channel environment and traffic characteristic.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.100-106
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• 2006

In this paper, we proposed a TxID(Transmitter Identification) system using ZCD (Zero Correlation Duration) code as interference-cancelled spread codes for single frequency network of ATSC terrestrial DTV broadcasting. ZCD codes are simply implemented and have ZCD characteristics. Then, Proposal system can fundamentally solve interference problems caused by ICI(Inter Code Interference) and MPI(Multi-Path Interference) which happens in TxID system using spread coding method. Also, those can cancel truncated error which happens at watermarking for TxID since those can remove its period. In this paper, we identified the availability of TxID system applying interference-cancelled ZCD codes by analyzing DER (Detection Error Rate) which is simulated in various interference environments such as AWGN, ICI, and MPI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1478-1489
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• 2006

This paper describes system to extract ISO codes in container image. A container ISO code recognition system for real-time processing is made of 5 core parts which are container ISO code detection and image acquisition, ISO code region extraction, individual character extraction, character recognition and database. Among them, the accuracy of ISO code extraction can affect significantly the accuracy of system recognition rate, and also the more exact extraction of ISO code is required in various weather and environment conditions. The proposed system produces binary of the ISO code's template lesions using an adaptive thresholding, extracts candidate regions containing distribution of ISO code, and recognizes ISO codes as detecting a final region through the verifications by using character distribution characteristics of ISO code among the extracted candidates. Experimental results reveal that ISO codes can be efficiently extracted by the proposed method.

• The Transactions of the Korea Information Processing Society
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• v.5 no.3
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• pp.703-714
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• 1998

Translation of a Korean text into a braille text causes no problem under the existing Korean braille-code System that maintains I: I correspondence between Korean characters and braille codes. However, reverse translation of a braille text into a Korean text would cause unavoidable mis-translation due to I : N correspondences between braille codes and Korean characters. The analysis shows that in Korean braille-code System, the major reasons for mis-translation are the conflicts between Korean Chosung (initial consonant) letters and numbers, between Korean Jongsung (final consonant) letters and punctuations, between Korean Jongsung (final consonant) letters and English mode delimiter codes, and overlapping use of the same braille code such as opening and closing parentheses. In this paper, we firstly established a reverse translation rule, that is to use an ordinary braille code unless the braille code causes any conflict in braille code sequences. If any ordinary braille code may cause some conflict during the reverse translation, an extended braille code that we propose in this paper must be used. In the experimentation, we cannot get any translation errors with the newly designed braille-code System compared with 25% of errors with the existing braille-code System.