• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2775-2787
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• 2021

At present, most of the widely used system codes for nuclear safety analysis are one-dimensional, which cannot effectively simulate the flow field of the reactor core or other structures. This is true even for the system codes containing three-dimensional modules with limited three-dimensional simulation function such as RELAP-3D. In contrast, the computational fluid dynamics (CFD) codes excel at providing a detailed three-dimensional flow field of the reactor core or other components; however, the computational domain is relatively small and results in the very high computing resource consuming. Therefore, the development of coupling codes, which can make comprehensive use of the advantages of system and CFD codes, has become a research focus. In this paper, a review focus on the researches of coupled CFD and thermal-hydraulic system codes was carried out, which summarized the method of coupling, the data transfer processing between CFD and system codes, and the verification and validation (V&V) of coupled codes. Furthermore, a series of problems associated with the coupling procedure have been identified, which provide the general direction for the development and V&V efforts of coupled codes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3458-3481
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• 2021

Existing methods for blind identification of linear block codes without a candidate set are mainly built on the Gauss elimination process. However, the fault tolerance will fall short when the intercepted bit error rate (BER) is too high. To address this issue, we apply the reverse algebra approach and propose a novel "two-step-screening" algorithm by solving the linear error equations on the binary Galois field, or GF(2). In the first step, a recursive matrix partition is implemented to solve the system linear error equations where the coefficient matrix is constructed by the full codewords which come from the intercepted noisy bitstream. This process is repeated to derive all those possible parity-checks. In the second step, a check matrix constructed by the intercepted codewords is applied to find the correct parity-checks out of all possible parity-checks solutions. This novel "two-step-screening" algorithm can be used in different codes like Hamming codes, BCH codes, LDPC codes, and quasi-cyclic LDPC codes. The simulation results have shown that it can highly improve the fault tolerance ability compared to the existing Gauss elimination process-based algorithms.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.437-451
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• 2003

With the rapid growth of internet technologies and wide availability of multimedia computing facilities, the enforcement of multimedia copyright protection becomes an important issue. Digital watermarking is viewed as an effective way to deter content users from illegal distributions. In recent years, digital watermarking has been intensively studied to achieve this goal. However, when the watermarked media is transmitted over the channels modeled as the additive white Gaussian noise (AWGN) channel, the watermark information is often interfered by the channel noise and produces a large number of errors. So many error-correcting codes have been applied in the digital watermarking system to protect the embedded message from the disturbance of the noise, such as BCH codes, Reef-Solomon (RS) codes and Turbo codes. Recently, low-density parity-check (LDPC) codes were demonstrated as good error correcting codes achieving near Shannon limit performance and outperforming turbo codes nth low decoding complexity. In this paper, in order to mitigate the channel conditions and improve the quality of watermark, we proposed the application of LDPC codes on implementing a fairly robust digital image watermarking system. The implemented watermarking system operates in the spectrum domain where a subset of the discrete wavelet transform (DWT) coefficients is modified by the watermark without using original image during watermark extraction. The quality of watermark is evaluated by taking Into account the trade-off between the chip-rate and the rate of LDPC codes. Many simulation results are presented in this paper, these results indicate that the quality of the watermark is improved greatly and the proposed system based on LDPC codes is very robust to attacks.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.165-168
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• 2000

The bit error rate(BER)of the data passed through Wideband-Code Division Multiple Access (W-CDMA) system with turbo-codes structure is presented. The performance of turbo-codes under W-CDMA system is estimated for various users and iteration numbers of decoding. The channel model is Additive White Gaussian Noise(AWGN) and Rayleigh fading channel. When iteration number increases, bit error probability of turbo-codes decreases. and when the number of users increase, bit error probability of turbo-codes increases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.504-511
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• 2016

In this paper, MIMO system based on turbo equalization techniques which LDPC codes were outer code and space time trellis codes (STTC) were employed as an inner code are studied. LDPC decoder and STTC decoder are connected through the interleaving and de-interleaving that updates each other's information repeatedly. In conventional turbo equalization of MIMO system, BCJR decoder which decodes STTC coded bits required two-bit wise decoding processing. Therefore duo-binary turbo codes are optimal for MIMO system combined with STTC codes. However a LDPC decoder requires bit unit processing, because LDPC codes can't be applied to these system. Therefore this paper proposed turbo equalization for MIMO system based on LDPC codes combined with STTC codes. By the simulation results, we confirmed performance of proposed turbo equalization model was improved about 0.6dB than that of conventional LDPC codes.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.3
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• pp.1-11
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• 2023

Purpose: This research aims to facilitate a smooth transition from KCD-8 to ICD-11 through the study of ICD-11. Research design, data and methodology: Skilled Health Information Managers (HIMs) in Korea performed manual mapping and conducted a study of the code structure of ICD-11 chapters 11 and 12. Results: When comparing the granularity between ICD-11 and KCD-8, 58.1% of ICD-11 codes showed higher granularity, and 38.6% had similar granularity. The granularity of the circulatory system was higher than that of the respiratory system. When comparing the KCD-8 codes mapped by ICD-11 with the total 924 KCD-8 codes, it was found that about 50% of KCD-8 codes were not mapped to ICD-11. This means that 50% of diseases in the KCD-8 do not have individual codes as they did in ICD-11. Conclusions: ICD-11 demonstrated high granularity, indicating its effectiveness in describing cutting-edge medical technology in modern society. However, we also observed that some diseases were removed from KCD-8, while others were added to ICD-11. To ensure smooth statistics transition from KCD8 to ICD-11, especially for leading domestic diseases, integrated management, including the preparation of KCD-9 reflecting ICD-11 and ICD-11 training, will be necessary through the analysis of new codes and the removal of codes.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.393-401
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• 2000

Objectives : To evaluate the impacts of the DRG payment system on the behavior of medical insurance claimants. Specifically, we evaluated the case-mix index, the numbers of diagnosis and procedure codes utilized, and the corresponding rate of diagnosis codes before, during and after implementation of the DRG payment system. Methods : In order to evaluate the case-mix index, the number of diagnosis and procedure codes utilized, we used medical insurance claim data from all medical facilities that participated in the DRG-based Prospective Payment Demonstration Program. This medical insurance claim data consisted of both pre-demonstration program data (fee-for-service, from November, 1998 to January, 1999) and post-demonstration program data (DRG-based Prospective Payment, from February, 1999 to April, 1999). And in order to evaluate the corresponding rate of diagnosis codes utilized, we reviewed 820 medical records from 20 medical institutes that were selected by random sampling methods. Results : The case-mix index rate decreased after the DRG-based Prospective Payment Demonstration Program was introduced. The average numbers of different claim diagnosis codes used decreased (new DRGs from 2.22 to 1.24, and previous DRGs from 1.69 to 1.21), as did the average number of claim procedure codes used (new DRGs from 3.02 to 2.16, and previous DRGs from 2.97 to 2.43). With respect to the time of participation in the program, the change in number of claim procedure codes was significant, but the change in number of claim diagnosis codes was not. The corresponding rate of claim diagnosis codes increased (from 57.5% to 82.6%), as did the exclusion rate of claim diagnosis codes (from 16.5% to 25.1%). Conclusions : After the implementation of the DRG payment system, the corresponding rate of insurance claim codes and the corresponding exclusion rate of claim diagnosis codes both increased, because the inducement system for entering the codes for claim review was changed.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.845-849
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• 2012

The next-generation wireless communication requires fast transmission speeds with various services and high reliability. In order to satisfy these needs we study MIMO system used layered space time coded system (LST) combining space time trellis codes (STTC) with turbo codes. In LST, two codes that are inner and outer codes are concatenated in the serial fashion. The inner codes are turbo Pi codes suggested in DVB-RCS NG system, and outer codes are STTC codes proposed by Blum. The interleaver technique is used to efficiently combine two codes. And we proposed and simulated that a full iteration method between turbo decoder and BCJR decoder to improve the performance instead of only processing inner-iteration turbo decoder. The simulation results of proposed effective layered method show improving BER performance about 1.3~1.5dB than conventional one.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.147-155
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• 2012

Fountain codes ensure reliability and robustness for time varying channels in wireless communication. In this paper, the concatenated fountain codes for AWGN and slow fading channels are investigated. Wireless system model, which includes the concatenated fountain code and modulation, is proposed. Maximum achievable rate is used for analyzing the performance of the system model for AWGN and fading channels. Belief Propagation (BP) algorithm is used for exploiting the soft information received at the decoder. Simulation results show that, concatenated fountain codes performs significantly better than that of a conventional Fountain codes with large packet lengths for higher Signal to Noise Ratio (SNR) in slow fading channels.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1109-1112
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• 2002

A non-coherent synchronous all-optical code-division multiple-access (CDMA) network is proposed. In this network, symmetric codes derived from prime sequence codes are used. We present the construction of symmetric codes and show that the pseudo-orthogonality of the new codes is the same as that of the original prime-sequence codes while the cardinality of the new codes is larger than that of the prime sequence codes and the modified prime codes in the same field GF(p). Therefore, an optical CDMA LAN using symmetric codes can have a larger number of potential subscribers. The new codes allow designing fully programmable serial all-optical transmitter and receiver suitable for low-loss, high-capacity, optical CDMA LANs. It is also shown that compared to systems using modified prime codes the proposed system can achieve better BER performance for low received chip optical power.